Outside Operator Training PDF

Outside Operator Training Property of SNF Holding Property Company. of SNF. Distribution Distribution orisduplication or duplication is prohibit...

Outside Operator Training Property of SNF Holding Property Company. of SNF. Distribution Distribution orisduplication or duplication is prohibited prohibited without consent. without consent.  Permit Writer 1.) It is important to walk the job out before permitting any work. Walking out the job is a responsibility of BOTH the permit writer (usually an operator) and permit approver who is usually the shift supervisor. 2.) If a job scope change is needed, the Permit Writer must seek approval from Permit Acceptor prior to permitting the work. A review of the job, LOTO, and permit must be completed prior to scope changes. 3.) Generally and especially while the plant is running, board operators should not write permits for jobs in the field for which another operator actually has domain. 4.) Permit Approvers (not Permit Writers) are ultimately responsible for the permit being sufficient for the work; there may be a misconception that the permit writer is ultimately responsible. 2  PPE Matrix 3 10/22/2019 3  PPE Matrix 4 10/22/2019 4  PPE Matrix 5 10/22/2019 5  Plant Safety - Slips We cannot overemphasize the slipperiness of our product once it contacts water. You must avoid all puddles and seek to step on the driest walking surface you possible can. This may mean taking the long way. Work to address wet spots as quickly as possible. Don’t expect the next person to be looking down or even see the spot. Grating can be a most slippery walking surface. Avoid walking on them if at all possible. Step over it without overextending. Keep shoe soles clean. It is good to inspect your soles regularly especially if walking surfaces have any degree of moisture present. 3/12/2018 6  Plant Safety - Slips One Point Lesson Point of Interest: Slips on Walking Surfaces On February 20, 2020, five (5) individuals fell to the work floor as a result of areas with residual PAM powder that had gotten wet. The plant was undergoing an intense cleaning effort in preparation for a customer visit. The falls were as follows: Two (2) SNF operators were working on the margins of a barricaded area where pressure washing was occurring; One (1) Emulsions employee was passing through the Breezeway located between the Powders Building 1 and the Warehouse. One (1) contract employee working to squeegee water toward a vacuum truck hose fell as a second contract employee fell trying to catch the falling employee. Key Reminders Make sure that the barricade tape, which is hung around pressure washing or hydro- blasting, also covers the area that is or could be impacted by overspray. The Breezeway should be avoided when it is wet. Permanent barricades are being considered. Remember the site policy on working in wet areas. These areas must be posted/barricaded and safe work plans established with the Supervisor before entering them. To ensure that safe work practices related to slip prevention are being followed, use safety observers for the pressure wash crews. These include: o wearing rubber boats, o keeping boot treads cleaned of build-up & gunk, o Only walk or work on dry surfaces or a surface that has been thoroughly cleaned of powder/gel build-up, o Lean slightly forward and prepare for the force of the water when triggering a pressure wash machine; sometimes the force is enough to throw you off balance which can cause a fall. If there is a need for pressure washing areas containing PAM, a hydro mower (pressure washes but immediately sucks up the water) or floor grinder is a more preferred option for cleaning. 3/12/2018 7  Working in Liquids Notify Supervisor if you MUST work in liquid –Spill cleanup, sumps overflowing, etc –Routine tasks in hazardous area –More than just a wet floor!! Determine if the task MUST take place and is NECESSARY DO NOT wear leather shoes, chemical boots are required Barricade around the area immediately with Danger tape and install barricade tag indicating hazard and requirements –We have provided specialized barricade tape that states the requirements Clean boots after task 8 3/12/2018 8 Barricade Tapes 9 LOTO and Barricade Tags 10 Quarterly Inspection Color Code 11  Dissolution Tanks The process of charging raw materials to a Dissolution Tank: 1. Confirm with the Board Operator that the Tank is ready for additions 2. Add each raw material in the correct order - 1. Water 2. Acrylamide 3. Urea 4. Acrylic Acid 5. Caustic 6. Salt (If applicable to product) 3. Note – Keep Manual Valves Open only when adding a raw material 12  Dissolution Tank Ingredients Water (Solvent) Acrylamide (Monomer) Acrylic Acid or Sodium AMPS (Monomer) ATN (ATBS 50) (Monomer) Sodium Hydroxide (Caustic) (pH Adj.) Other Additives : Urea, Ammonium Sulfate, Salt 13  Polymer/Polyacrylamide Mono = one Poly = many Polymer = many –mers Polyacrylamide = Many acrylamide monomers. (Charge using Acrylic Acid). 14  Monomers Acrylamide – Neutral Backbone Acrylic Acid – Anionic Backbone Sodium AMPS (JMS50) – Anionic Backbone All are dissolved in water and charged with Caustic (NaOH). 15  Flocculation Colloid – A substance that is microscopically dispersed within another substance. e.g. pond water (dirt in water), milk(fat in water), etc. Floc – The grouping of the dispersed substance (via polymer) to overcome molecular interactions, and settle out (settle the colloid out of the solution). 16  PolyACM Types & Differences Anionic = (-) Charge - Acrylic Acid / Sodium AMPS / Acrylamide Cationic = (+) Charge - Cationic Monomer / Acrylamide Nonionic = ( ) Neutral Charge - Acrylamide 17  Raw Material and Hazards Following slides contains commonly used raw materials and some associated hazards. Always consult SDS for all raw materials for complete list of hazards and handling. Water 18  Raw Material and Hazards ACRYLAMIDE (Most hazard in a solid form)(Carcinogen) TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS INHALATION Cough. Sore throat. Weakness. SKIN MAY BE ABSORBED! Redness. Pain. EYES Redness. Pain. INGESTION Abdominal pain. Weakness. 19  Raw Material and Hazards UREA TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS Causes irritation to the respiratory tract. INHALATION Coughing, shortness of breath. Causes irritation to skin. Symptoms SKIN include redness, itching, and pain. EYES Causes irritation, redness, and pain. Causes irritation to the gastrointestinal INGESTION tract. nausea, vomiting and diarrhea. 20  Raw Material and Hazards ACRYLIC ACID TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS EXPOSURE Cough. Sore throat. Shortness of breath. Burning sensation. Laboured INHALATION breathing. Corrosive. Symptoms may be delayed. MAY BE ABSORBED! Redness. Blisters. SKIN Pain. Redness. Pain. Severe deep burns. EYES Loss of vision. 21  Raw Material and Hazards Caustic TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS Only if it becomes an airborne dust or INHALATION mist. Can cause severe irritation of the nose and throat. CORROSIVE. Contact can cause pain, SKIN redness, burns, and blistering. Severe exposure can cause death. CORROSIVE. Contact causes severe burns with redness, swelling, pain and EYES blurred vision. Permanent damage including blindness can result. Can burn the lips, tongue, throat and stomach. Symptoms may include INGESTION nausea, vomiting, stomach cramps and diarrhea. Can cause death. 22  Raw Material and Hazards Salt TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS No known hazards. No known hazards. 23 ATN Grades Used in Powders Process Plaquemine ATN is currently designated in two grades: XG – Highest quality of ATN and most be conserved for the key designated grades – For use in all ATN-containing Post-Hydro Products – For use in the standard product, AN 125SH/VHM HQ (does not stand for “highest quality – Lower quality of ATN used for standard products such as AN 113SH/VHM, AN 118SH/VHM 24 3/12/2018 24  Inhibitors Acrylamide is inhibited by copper and oxygen. Copper is added when the acrylamide is manufactured. The copper is usually added in an amount of approximately 25 parts per million by weight. The copper inhibits polymerization by reacting with any free radicals before the free radicals can react with monomer molecules. Usually these free radicals come from contamination from various pumps, pipes and tanks. Oxygen is added to the acrylamide by air sparge. Oxygen inhibits polymerization by reacting with free radicals and forming a more stable free radical. The unpaired electron in the new free radical is delocalized which results in a more stable radical which is unable to initiate a polymerization reaction. 25  Inhibitors An inhibitor is anything that interferes with free radical polymerization. – The main inhibitor that we use is MEHQ (Hydroquinone Monomethyl Ether) – MEHQ prevents auto-initiation in the dissolution tanks. 26  Inhibitors Cationic monomer and acrylic acid are inhibited by MEHQ (mono methyl ether of hydroquinone) and oxygen. Cationic monomer also is inhibited by Versenex 80 (20-80 ppm). MEHQ transfers a hydrogen atom to a free radical and forms a stabilized radical which is unable to act as an initiator. 27  Dissolution Tanks 28 28 6/10/2024 Why Should we keep each raw material valve closed when not in use? This line can hold up to 25-30 kg of excess raw material Our product is very pH Sensitive to propagating the polymerization process. This could be the difference in making a Dead/Slow reaction and a Good Reaction 29  BVE BVE is used in the production of A 3338. When BVE is used, more foam is generated. Thus a special anti-foam call Sag 30 is used in conjunction with BVE. 30  Anti-Foam Anti-foam is used to remove the foam from the dissolution tank before its transferred to the reactor. If the foam is not removed from the dissolution tank before the transfer it might get sucked over to the granulator transport fan. Adding to much anti-foam will cause a slow heat up in the reactor. Adding to little anti-foam will allow the foam to regenerate during the transfer causing the catalyst to sit on top of the reaction not allowing it to mix properly. 31  Measurement of Additives in Dissolution Tanks Powders plant utilizes a mass flow meter to calculate the amount of liquid moving through a pipe line and derives a total. Powders plant use both mass flow meters and pressure transmitters to measure the amount of product in a dissolution tank. Pressure transmitters measure the amount of force the solution is pressing on the membrane. The higher the level of the solution in the tank, the greater the pressure at the bottom of the tank. In-Line pH Meters For powders plant there are in-line pH meters on the recirculation lines. The in-line pH probes are useful when acids and bases are being added to the dissolution tank. 32  Adjusting pH The pH of a dissolution tank should be adjusted carefully so that the polymerization pH is reached without “over-shooting” the pH. Raising pH Caustic should be used to raise the pH in a dissolution tank for Non-Ionic and Anionics products. For Cationic products caustic should never be added. If the pH must be raised for Cationic products, the dissolution tank should be split and tanks recharged. “Over-Shooting” the pH can cause hydrolysis which causes an increase in anionicity of the final product. 1: For high anionics (AN 977 and above) the cause should be charged at 80% in two batches. Allow the tank to mix for 10 minutes between caustic charges and check pH. If the pH is below the polymerization pH, caustic should be added slowly. The tank should be mix for 5 to 10 minutes before re-checking the pH. Lower PH If the caustic is overcharged and the pH is less than 12.0 1: Use Sulfuric acid to adjust pH. Add the acid one liter at a time, allowing the dissolution tank to mix 5 to 10 minutes before re-checking the pH. When the pH is close to the target, caustic should be added in 250 to 500 mL increments, until the polymerization pH is reached. If the caustic is overcharged and the pH is between 12 and 13 Note; a supervisor must be called if the pH is overshot to a pH above 12 If the caustic is overcharged and the pH is above 13. Acrylic acid should be immediately added until the pH is dropped below 8.0. The tank should then be split and recharged. A supervisor/technician must be notified after adding acrylic acid. 33  pH probe pH probes are calibrated using buffer solutions with a known pH value. Bench top calibration instructions: EPDM (PAM-COM-005) 34 Acrylic Acid Acrylic gives the product its charge. Anionic have a negative charge. To much acrylic acid will result in high anionicity. To little acrylic acid will result in low anionicity. 35 Acetic Acid Acetic acid is used for pH control in the post hydro process. This type of acid is used so anionicity will not be adversely affected. 36 Salt Tank The biggest issue with the salt tank is oversaturation by the addition of too much salt. Not recording or forgetting how much salt has been added, is a huge concern. The agitators must be checked during shift rounds to ensure they are spinning. Going for relatively short periods of time with no agitation in a salt tank will lead to clogging issues in the pump suction piping or within the tank itself. The most common salt solutions used in Powders production are solutions of NaCl. This is for SHU grade PAM. 37  Sampling a Dissolution Tank All Dissolution Tanks made are required to have a retaining sample. – But Why? Our product is affected by polymerization issues and drying upsets In order to differentiate our process upset, we need to identify our trouble equipment. – When Can I get rid of previous samples? Once a corresponding Reactor sample to QC Silo Blend is Conformed 38  D-Tank Transfer Pump Centrifugal pumps are used to transport aqueous phased solution to the reactors. Centrifugal pumps are used to prevent equipment damage in the event of high back pressure or clogging. This is primarily due to the relatively fragile “tube and shell” glycol heat exchanger. A damaged or leaking exchanger could cause cooling system or batch contamination. Centrifugal pumps can be dead headed for short periods of time without damaging the pump or building excessive pressure. A motor monitor is in place to protect the motor when the pump is dead headed are during pump cavitation. We also have a low level probe on the discharge side of the pump that will shut down the pump when its see no level in 39  Dissolution Tank Temperature The dissolution tank is cooled to prevent auto- polymerization and to provide product consistency by beginning polymerization at the initiation temperature target of 0 degrees C. – -2 degrees C in the dissolution tank equals 0 degrees C in the reactor after transfer. The dissolution tank temperature target is changed according to season in order to maintain 0 degrees C at the Rx. If the dissolution tank was set to -3 degree C opposed to -2 degree C this will cause the reaction to take off a little slower thus lowering the U.L. Caustic additions cause the dissolution tanks to heat up. – If the dissolution tank exceeds 15 degrees C it will alarm and prevent a caustic addition. If the temperature exceeds 25 degrees while a caustic addition is in progress shut down logic will be initiated and shut the caustic addition off. 40  Environmental Aqueous solutions must be stored in a diked area to control and accidental spills. This is to prevent environmental damage and so spilled materials can be recovered. Finish product is bad for aquatic organisms. Any water or condensate that accumulates in a plant sump or dike should be tested for pH before pumping to Wastewater. If the pH is not within 6.0 and 9.0, the liquid must be neutralized with an appropriate acid (if pH is high) or basic/alkaline material (if pH is low). See appropriate site/plant procedures for managing pumping and preparing to pump liquids to Wastewater. 41  Rotation Checks Mechanics & Electricians should be trained on proper direction for everything they work on. Equipment should never be turned over to Operations that is turning backwards. However, Operations personnel should be trained on proper direction for everything they operate. Operations personnel will have ultimate responsibility for direction of rotation. No permit for work involving the dis/reconnection of electrical motors should be signed off as complete until a process person has verified that it is turning in the proper direction. If, for some reason, proper rotation cannot be verified, the Manager must be notified so that he can follow up, through investigation, training, application of a rotation label, etc. 42  Leak Checks Following Line or Equipment Openings/Breaks When possible, equipment should be pressure tested in the shop before installation. That includes pumps, pre- fab’ed manifolds, etc. Systems must be checked for leaks by operations. Hazardous material systems (AN, AA, NaOH, Oleum, etc.) must be pressurized & leak checked prior to return to service. – If that is not possible, the Op’s Manager must develop a contingency plan, possibly including instruction on special PPE and safe monitoring distances during equipment recharge. Non-Haz systems can be pressure checked or monitored, at the discretion of the Supervisor. 43  Environmental – Empty Drum/Tote Management On the exterior, ensure the container is clean of all residues. – Pressure washing may be required. After the container contents are consumed as much as possible (RCRA empty), the container should be rinsed with a few gallons of water. – If the raw material is used in the current D-tank recipe, the rinse can normally be poured into a D-tank or split between two or more D-tanks. – Just as with the exterior, pressure washing may be required to remove the raw material heel/residue (e.g., Anti-foam). 44  Environmental – Empty Drum/Tote Management Emulsions normally manages a empty drum roll-off bin. If we have 4 or less drums, we can normally put them in their roll-off. – The roll-off bin is typically for plastic or metal drums. – The Powders Shift Supervisor should talk to the Emulsions Shift Supervisor on use. They like to track what is put in their and may already have a full load designated for the bin. – Emulsions usually has a Day Operator that loads these drums (e.g., Kandel Bynum); he/she can be called as well. – Do not discard any trash or pallets into this drum bin. Emulsions normally manages empty totes. The majority of these totes are stored on the south wall of the warehouse. – Until a designated area for Powders is provided and posted, use the same communication protocol with Emulsions personnel. 45  Reactor Type SNF has two type of reactors used to make polyacrylamide. The Plaquemine plant uses “Tube Reactors” that have an electro-polished coating on the interior reactor walls. 46  Oil Reactor Before Drawdown Oil prevents the gel from sticking to the internal Rx parts, thus preventing contamination. Oil also improved Rx draining speed as well as reduce equipment strain caused by friction. 47 Dissolution Tank To Reactor Draw Down Diagram Flow Meter H e Glycol out a t E x c Dissolution h a Rx n Tank g e Glycol in r 48  Polymerization Table Color Code Color Category Examples Blue Reducers MBS Orange Oxidizers Ammonium Persulfate TBHP Sodium Hypophosphite Brown Chain Transfer Agents (HYPO) White Metals Mohr Salt MBA Yellow Crosslinkers Versenex Green Chelating Agents 49  Catalyst Handling Mixing of Oxidizing and Reducing catalyst will result in a violent chemical reaction that can cause serious bodily injury including chemical and thermal burns, sever trauma, and even death. Up most care and high housekeeping standards must be maintained at all times while handling catalyst. Properties/Hazards associated with Oxidizers, Reducers and Thermal Catalyst Oxidizers TBHP Chemical Name: Tert-butyl Hydrogen Peroxide Form: Slight yellow liquid with a strong distinct odor Storage Conditions: Below 86 degrees F or 30 degrees C in a dry, well- ventilated area Incompatible with strong acids and reducing agents TBHP is stored in flammable cabinet because it can cause a fire if it comes in contact with a reducer 50  Catalyst Handling Persulfate Chemical Name: Ammonium Persulfate Form: White crystalline with slight odor Storage Conditions: Cool, dry place away from heat Incompatible with acids, bases, halids (chlorine and bromines), most metals (specially copper and lead), reducing agents, and most cleaners Potassium Bromate Chemical Name: Potassium Bromate Form: Storage Conditions: Incompatible with Reducers MBS Chemical Name: Sodium Metabisulfite Form: White crystalline with strong odor Storage Conditions: Cool, dry and well ventilated area Incompatible with Oxidizing agents and acids; also corrosive to aluminum in aqueous solutions Decomposition Products (when heated above 300 degrees F or 148 degrees C): sulfur Dioxide which corrosive to skin, mucous membranes and teeth 51  Catalyst Handling Iron/Mohr’s Salt Chemical Name: Ferrous Ammonium Sulfate Form: Light Green crystalline with no odor Storage Conditions: Cool, dry area Incompatible with Oxidizing agents Decomposition Products (when heated above 212 degrees F or 100 degrees C): Sulfur dioxide, Ammonia and Nitrous Oxide (Laughing Gas) Hypo – used as a chain-transfer agent but has reducer properties Chemical Name: Sodium Hypophosphite Form: White crystalline with slight odor Storage Conditions: Cool, dry, fire-resistant area Incompatible with strong oxidizing agents and bases (such as caustic) Decomposition Products (violently decomposes above 545 degrees F or 285 degrees C): Phosphine gas – Phosphine gas is a colorless, odorless, flammable gas that is highly toxic in low concentrations; it is often used as a pesticide and rat exterminator. 52  Catalyst Handling Thermal Catalysts VA-044 Chemical Name: 2,2’-Azobis(2-(2-o,odazp;om-2-yl) (propane)dihydrochloride Form: White powder with no odor – Dust may form explosive mixture with air Storage Conditions: In temperatures less than 104 degrees F or 40 degrees C, away from direct sunlight, well ventilated, dry area with lightly sealed lid Incompatible with strong oxidizing agents, strong acids and persulfates Decomposition Products (when in temperatures above 104 degrees F or 40 degrees C): Nitrogen gas, carbon monoxide, and ammonia 53  Catalyst Handling AZDN/VAZO 64 Chemical name: 2,2’-Azodi(isobutyronitrile) Form: White powder with medium odor – Dust may form explosive mixture with air Storage Conditions: Cool, dry area below 75 degrees F or 24 degrees C Incompatible with strong oxidizing agents and reducing agents Decomposition Products (when in temperatures above 122 degrees F or 50 degrees C): Nitrogen gas and Terramethyl Succinonitrile – Tetramenthyl Succinonitrile is a gas that is extremely permeable to the skin and mucous membranes; it causes central nervous system shutdown, including dizziness, confusion, in coordination, convulsions and unconsciousness; over-exposure is fatal. – Never over fill the Vazo pot when mixing this catalyst. 54  What is Hypo Doing? Free radicals can also be created by a chain transfer agent. A commonly used chain transfer agent at SNF Flopam is sodium hypophosphite. Chain transfer agents create free radicals when they react with a growing polymer molecule. When a chain transfer agent reacts with a polymer molecule, the growth of that molecule is terminated and a free radical is created. This new free radical will then initiate the growth of another polymer molecule. This is where the term "chain transfer" is derived from since a chain transfer agent terminates one polymer chain and starts the growth of another chain. Slower reaction curve indicate higher hypo weight. Faster reaction curve indicate lower hypo weight. 55  Hypo (DEA List 1 Chemical) Sodium Hypophosphite (DEA List I Chemical), FCC is used as an emulsifier and stabilizer. The FCC grade meets the requirements of the Food Chemical Codex indicates and is suitable for all food, beverage and nutritional supplement applications. All listed chemicals as specified in 21 CFR 1310.02 (a) or (b). This includes supplements which contain a listed chemical, regardless of their dosage form or packaging and regardless of whether the chemical mixture, drug product or dietary supplement is exempt from regulatory controls. For each chemical, its illicit manufacturing use is given in parentheses. Some Special Surveillance List chemicals do not have an exclusive manufacturing use for a specific illicit drug but rather have a broad range of uses in both legitimate and illicit manufacturing operations. 56  Hypo (DEA List 1 Chemical) This chemical should be in a cage under lock and key at all times by both Powders and Emulsion. 57  Catalyst Storage Only store 24 Hrs. worth of catalyst in the plant. 58  MBA in A3338 Too much MBA – lots of crosslinking Undercharging the MBA would cause a low UL. Too much MBA will cause poor solubility which results in a low UL. 59  MBA & MBS Confusion Because both chemicals start with “MB”, MBA can easily be confused with MBS. Remember that MBA is seldom used (currently only in A3338) and should be isolated from MBS. MBA has a much longer dissolution time and does not have the pungent odor that MBS does. – Students should be allowed to smell the two chemicals. So that they can remember the difference. –MBSmells!!! 60  Thermo-Catalyst Thermal catalysts are compounds that decompose between 30 – 40oC producing free-radicals that initiate further reaction of the polyacrylamide solution. Thermal catalysts are from the Azo family of compounds, meaning that they contain a R-C-NΞN-C-R bond. The R-C-NΞN-C-R bond decomposes at high temperatures and produces two identical free radicals (R-C∙) and nitrogen gas (N2). The most common thermal catalysts used at Chemtall are Vazo 67, Vazo 64/AIBN, Vazo 52, AZDN, and ABNR. Also, VA- 044 which is used as an additional catalyst in higher molecular weight products (PG0, VHM). If no thermo- catalyst is not added to the reaction the reaction will peak out at a slower rate. 61  What is Vazo doing? VAZO 64 is the thermal catalyst we use to “finish” polymerization. When exposed to temperatures above 30 °C, the molecules of VAZO 64 will start to decompose and create two free radicals. In polymerization, as the thermal catalyst decomposes, it gives off free radicals which in turn speed up the polymerization process. As polymerization takes place, heat is given off which breaks down more of the VAZO 64 molecules. This process repeats itself until all of the monomer present in a reaction has been polymerized or the thermal catalyst has been used up. 62  What is VA-044 doing VA-044 is another thermal catalyst we use in the polymerization process. VA-044 degrades at a slightly lower temperature than VAZO, and acts as a”bridge” between the redox catalysts and the VAZO. At low temperatures, it is inert, but at higher temperatures it creates free radicals in solution. VA-044 is used more often in higher molecular weight products to prevent reactions from stalling or dying before the VAZO initiates. 63  Catalyst Mix times AZDN – 5 min Mixing times should be followed always. Versenex 80 – 3 min Mixing too long can cause catalysts to lose Hypo – 5 min effectiveness, which can result in slow heat ups or a VA-044 – 5 min dead batch as evidenced in the pictures below. Sodium Persulfate – 5 min Brownish gel color means unreacted catalyst. TBHP – 30 seconds Mohr’s Salt – 1 min (must use RO water only for this catalyst) Good Reaction: Bad Reaction: 64  Catalyst Add Time Catalyst is added on a time basis to assure it mixes properly throughout the reaction before the initiation process. 65 Why do we need to be precise with Hypo weights? Each polymer we make has a different molecular weight. – This is due to our chain transfer agent (“Sodium Hypophosphite”) – So what does that actually mean? We use “Hypo” to regulate the molecular weight for a product and reduce our insolubles Large Amount of Hypo Added Small Amount of Hypo Added Low Molecular Weight Product High Molecular Weight Product 66 I’m done polymerizing my Reactor, Can I discard my catalyst bags? TBHP Waste Receptacle Yes, discard catalyst bag (Verified empty, no residual) – The waste receptacles must be emptied into separate waste bags, tied off, and disposed of in plant trash once a week. Supervisor will audit bag Weights on a random basis. 67  Polymerization Reaction Free Radical Polymerization 1. Thermal Degradation – Thermal Catalysts 2. Redox Reactions – Reducers + Oxidizers There has to be a balance of the two. 3. Chain Transfer Agents – Create free radicals with a growing polymer chain. 68  Polymerization Reaction 1. Redox Reactions – Oxidizers: Sodium Persulfate Tert-Butyl Peroxide (TBHP) Potassium Bromate – Reducers: Sodium Metabisulfate (MBS) Sodium Sulfite Mohr’s Salt (Iron) Sodium Formaldehyde Sulfoxialte (NaFS) 69  Redox Reactions Redox reactions are used to initiate the polymerization. We then measure the induction period to ensure that the reaction has actually started. Induction time is the time between when the reducer is transferred until the reaction temperature changes 0.20C on the temperature panel in the field. – This is usually less than 60 seconds, but can be up to a few minutes. Induction time is usually shorter for lower molecular weight products and longer for higher molecular weight products. Great care must be taken not to mix oxidizers with reducers outside of the reactor, as an explosion can occur. Increasing the redox catalyst will result in a faster kinetic. Decreasing the redox catalyst will result in a slower kinetic. 70  Redox Reactions In general, we use Mohr’s Salt (Iron) as our main reducer to kick off a reaction: – TBHP + Mohr’s Salt Mechanism H2O2 + Fe2+ → HO∙ + -OH + Fe3+ – Amm. Persulfate + Mohr’s Salt Mechanism S2O82- + Fe2+ → S042- + ∙S04- + Fe3+ 71  Polymerization Reactions 2. Thermal Degradation – Thermal Catalysts: Vazo67, Vazo64/AIBN, Vazo52, AZDN, ABNR, VA-044 – Thermal catalysts must be stored in cold storage to keep them chemically stable, and to extend the shelf life up to or past 3 months. If thermal catalysts are not kept in cold storage, they can begin to degrade and form free radicals. This is why following the FIFO (first in, first out) inventory method must be done. A byproduct of the degradation of Vazo64 is TMSN (tetramethylsuccinonitrile) , and is a highly toxic. 72  Thermal Degradation Thermal degradation accelerates the reaction to completion. – Without thermal catalysts to accelerate the reaction, the UL viscosity would build very slowly, and too large; so large as to degrade solubility. – Different thermal catalysts degrade at different temperatures and react for a different amount of time. 73  Polymerization Reactions 3. Chain Transfer Agents – Create free radicals when they react with a growing polymer chain. The polymer chain is terminated and a free radical is created. The new free radical will initiate the growth of a new polymer chain. Molecular weight of the polymer is manipulated by changing the concentration of chain transfer agent used in each reaction. 74  Steps of Polymerization There are three steps to Polymerization Initiation Propagation Termination 75  Polymerization Initiation – Free radicals attack C=C bond in the monomer molecule, creating a free radical on the end. – Initiation occurs when the reducer from the redox package is added to the monomer solution. 76  Polymerization Propagation – The newly formed free radical at the end of the monomer attacks other C=C bonds on other monomers, creating a chain of monomers, or polymer. – The chain will continue to lengthen until there are no more monomers available, or until a chain transfer agent terminates the chain and starts a new chain. – Thermal catalysts and chain transfer agent drive the propagation step. 77  Polymerization Termination (3 Causes) – Absence of monomer – Disproportionation – When another free radical attacks the end of the polymer chain, not allowing a new free radical to form. – Combination – Occurs when two chains with free radicals combine. 78 Reaction Curve Polymerization Steps 79  Auto Initiation Can happen if hot gel is left over from the last reaction. If the solution is not at the set point in the dissolution tank during the transfer to the reactor. If there is left over catalyst in the reactor during the drawdown. 80  Sparging Sparging is a very critical factor in making in-spec polymer. Sparging is the injection of nitrogen at the base of the reactors to displace oxygen in the reactor and dissolve in the polyacrylamide solution. Oxygen is an oxidizer and will inhibit the redox reaction from occurring. If the sparge pressure or flow-rate is too low, not enough oxygen will be removed from the batch during the set sparge time and there will be inadequate mixing of the catalysts. This causes the reaction to be slow to start, resulting in an erratic reaction rate. If the sparge rate is too high, this can lead to poor catalyst mixing and erratic curves resulting in off-spec product. High sparge rates can also cause foaming in the reactor which can cause carry over of monomer into the venting system. If there are leaks in the nitrogen line it is possible to create a Venturi effect resulting in air being sucked into the nitrogen line causing initiation and kinetic problems. If the DCS is reading a low sparge rate the issue could be a clog sparge cone are a closed valve. 81  Why Nitrogen is Required? When nitrogen is injected into the reactors it is called sparging. Sparging displaces the oxygen in the solution and reactor, which inhibits the polymerization reaction from occurring. If the sparge pressure or flow- rate is too low, not enough oxygen will be removed from the batch during the set sparge time. If the sparge rate is too low, there will also be inadequate mixing of catalysts, causing the reaction to be slow to start or causing an erratic reaction rate, leading to off-spec product. If the sparge rate is too high, this can lead to poor catalyst mixing and erratic curves resulting in off-spec product. If there are leaks in the nitrogen lines, air could be pulled into the sparge lines and oxygen will be added to the reaction instead of removed from the reaction, causing a slow start or a dead batch. This phenomenon is called a Venturi effect (sucking outside air into the pipe via a pressure drop inside the line) and occurs when you have a restriction in the nitrogen line (i.e. Valves or Sparges). This it is why it is important to have a good tight fit around the sparges. 82  Nitrogen Hazards SYMPTOMS OF OVER-EXPOSURE BY ROUTE OF EXPOSURE: The most significant route of over-exposure for this product is by inhalation. Nitrogen is a colorless, odorless gas. The main health hazard associated with releases of this gas is asphyxiation, by displacement of oxygen. INHALATION: Due to the small size of an individual cylinder of this product, no unusual health effects from exposure to the product are anticipated under routine circumstances of use. If this product is released in a small, poorly ventilated area (i.e. an enclosed or confined space), an oxygen-deficient environment may occur. Individuals breathing such an atmosphere may experience symptoms which include headaches, ringing in ears, dizziness, drowsiness, unconsciousness, nausea, vomiting, and depression of all the senses. Under some circumstances of over-exposure, death may occur. The following effects associated with various levels of oxygen are as follows: CONCENTRATION SYMPTOM OF EXPOSURE 12-16% Oxygen: Breathing and pulse rate increased, muscular coordination slightly disturbed. 10-14% Oxygen: Emotional upset, abnormal fatigue, disturbed respiration. 6-10% Oxygen: Nausea and vomiting, collapse or loss of consciousness. Below 6%: Convulsive movements, possible respiratory collapse, and death. 83  Chelating Agents When aqueous acrylamide is supplied from anywhere besides SNF Flopam, it is inhibited with copper metal in solution to prevent premature initiation. The copper must be separated from the acrylamide so that we can control the initiation to when we want it to start. We use the chelating agent Versenex 80 to accomplish this. – Versenex 80 has the largest affinity (or desire) for copper. – It also has an affinity for Iron, which we use to start a reaction. To keep the Iron free and available for free radical formation, we must take care to use the correct amount of Versenex 80. 84  Chelating Agents Note: – Versenex 80 can also be used as a catalyst if a large amount is added to a reaction. – Excess Versenex 80 will chelate all the copper and iron. Chelated iron is much more reactive than unchelated iron and will accelerate the reaction, thus acting as a catalyst. 85  Branching and Cross-linking Branching increases molecular weight without increasing the viscosity. – Certain applications can benefit from this characteristic. – Branched products still have good solubility. Cross-linking is extreme branching that decreases solubility. – For our purposes, cross-linking is not desired, and should try to be avoided. 86  Product Solubility Solubility is the measure of a polymers ability to dissolve in water. The primary reason for poor solubility is excessive temperatures in the dryers and during polymerization in the reactors. In either case the issue is caused by crosslinking the polymer. During polymerization the following could cause poor solubility: Primary reasons: – UL too high – Branching agent concentration too high – Residual acrylamide too high 87  Hydrolysis Hydrolysis is a chemical reaction where water with another substance to form two or more new substances. – In polyacrylamide production, hydrolysis occurs when the neutral amine group on the polymer chain is converted to an anionic acrylic acid tail, giving the chain a negative charge. The more hydrolysis that occurs, the higher the charge of the polymer chain. We use caustic for hydrolysis in our reactions. The temperature of the aqueous monomer during the addition of caustic shoots up, so we must make sure to leave the heat exchanger running and not allow the temperature to rise above 12°C. Hydrolysis occur more in lower anionic product causing a blue/green tint 88  Kinetics Is the rate of temperature vs time – Is measured on a x-y chart. Temperature – Most reactions start at 0°C, and heat up to 75-100°C Some products are initiated at higher temperatures, but never above 20°C. If the reaction does not reach a high enough temperature, there will be left over monomer in the form of a liquid. Federal regulation will not allow us to sell polyacrylamide with a monomer content over 1000ppm. A reaction that rises above 100°C will cause the water in the reaction to convert to steam and expand the gel into the vent line. This should be avoided as much as possible. If this occur check the dissolution tnk charge and catalyst package. 89  Kinetics Time – Reactions can take from 30 minutes to over 3 hours to run. The amount of time it takes will depend on the molecular weight of the product. Reactions that run too quickly will likely have a low UL viscosity (off- spec). Reactions that run too long will likely not reach a high enough temperature and have a high monomer content. 90  Free Monomer “Free Monomer” are the unreacted or un-polymerized monomer molecules used to make Polyacrylamide gel. Free monomer is the measure of the amount of acrylamide that has not been converter into polyacrylamide. Free monomer normally happen when the plant have a leaking drain valve. 91  Molecular Weight The molecular mass (m) is the mass of a given molecule: it is measured in unified atomic mass units (u or Da).Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. 92  Reactor Why do we need Reactors? The reactors are vessels where we charge the liquid monomers and change this mix into polymer gel. The process of making gel is called polymerization. Polymerization begins when the Polymerizer removes the oxygen and adds the catalyst. Our products are sold based on the length of the resulting polymer chains and the charge of the chains. The longer the polymer chains the harder it is to dry the polymer without causing solubility problems. 93  Reactor How does the Reactor work? The polymerizer fills the reactors with a mix of monomers (acrylamide, acrylic acid, amps, or cat monomer), water, additives, and pH adjusters. This mix is polymerized by sparging with nitrogen and by the addition of catalyst. Heat is released as the monomers react to form polymer chains. This heat makes the gel hot. The mixture starts at the freezing point of water, 0 ∘C, and can peak out near the boiling point of water, 100 ∘C. The primary characteristics of the products we make are charge and molecular weight (chain length). These are created in polymerization. The charge is created by adding acrylic acid or cat monomer. The molecular weight is increased by decreasing the amount of catalyst and chain transfer agent. The polymerizers record when the gel should be dumped on the dry erase boards located near the dryer control board. The dump time is calculated by determining the peak time and adding the hold time. The peak time is the time at which the temperature of the gel stops increasing. At this point almost all of the monomer has reacted. The hold time is determined by the Lab. This is the time needed to lower the residual monomer within spec. The hold times are usually 1, 2 or 3 hours depending on the product. Low anionic product should not be held longer than the hold times or the anionicity could increase to where the product is out of spec. The process where this happens is called hydrolysis. Hydrolysis happened if the gel is held at high temperature for too long or if the pH is too high or too low. Hydrolysis will cause anionics’ negative charge to increase and the cationics’ positive charge to decreases. Anionics above 923 and most cationic can be held in the reactor without significantly affecting the quality. Holding the gel more than 3 hours has little benefit in reducing the monomer. 94  Reactor How does the Reactor work?( Continued…) Once the dump time is reached the gel is ready to be dumped. The dryer operator should double check to make sure the right reactor is being dumped. Check the temperature read out for the reactor, if the temperature is below 75C the gel may not be ready to dump. Mistakes can be made when one reactor is not used and gels are set to dump out of order. It is important to check that the correct reactor is chosen before it is dumped. Dumping the wrong reactor will spill un-reacted monomer into the pregrinder, granulator, column screw or on the floor. If something does not seem right, it probably isn’t. Ask the polymerizer, team leader or supervisor to verify that the reactor is ready to dump if something seems wrong. Once the reactor is dumped, the Dryer Operator may spray 60/30/10 on the liner of the empty reactor. This will make it easier to dump the gel out of the reactor on the next batch. The amount is listed on the conditions sheet. The tube reactors are dumped by pressurizing the reactor and forcing the gel through a discharge pipe. 95 Reactor Trouble Shooting The polymerizers maintain the reactors. The dryer operators help lubricate the reactors so that they will dump/discharge more easily. If the reactors will not dump/discharge the liners may be bad. The reactors are lined with: a Teflon-like coating, or they are electro- polished. If the gel will not dump and the lubrication is good, the liners may need to be changed. If the reactors peak at too hot of temperature the cause could be too much monomer and not enough water. Or the reaction could have been started at too high a temperature. If the batch peaks above the boiling point of water the gel can be forces violently out of the reactor. Gel forced from the reactor can result in injury to operators or damage to equipment. Different temperatures between the reactor temp probes could be because of a bent are bad probe. BO operator pressure test every reactor before the drawdown to check for leaks. 96  What to Do When Bad/Slow Reaction Detected? Inform supervision and Poly Tech ASAP. Immediately get D-tank sample to Poly Tech for analysis and performance testing. Assist with information gathering. Review Troubleshooting Guide for the condition you are experiencing. Review Bad Reaction Handling/Management protocol to help minimize the potential for downstream processing problems. Technical Staff will need to be involved with ultimate decision-making. Some of the possible actions might include: – Sucking out the reaction using a vacuum truck – Allowing the reactor to sit until it finally peaks. This may take over a week. – Separating the gel via a download/upload/download. 97  Reactor Safety Concerns The safety considerations are that the gel is very hot and can cause burns. Contact with the gel should also be avoided. The surfactant on the gel can cause skin irritations. The gel is also very heavy it is important to make sure a gel is not dumped on someone working in the pregrinder. The liquid monomer is poisonous. It is important not to dump a reactor before the reaction is complete. The reactors nitrogen sparges can leak and cause death from lack of oxygen in closed environment like the reactor or pregrinder. When working in the pregrinder make sure the nitrogen lines are disconnected. Lock-out the reactor before doing any work inside the pregrinders. A line break and confined space permit must be completed before entering the reactor. The reactors are a vital part of the process, and like the other equipment must be used wisely and safely. 98  Reactor Solenoid Panel Solenoid Control panel Authorized employees: Electricians Electricians Supervisor Electrical Specialist (Clint Rogers/Jeremy Poche.) No one else should be inside of the control panel. If possible, try only to work inside boxes which have reactors already gelled or completely empty. Disabling Air to Actuated valves: Two Preferred Methods: Single piece Equipment: Disconnect air supply from actuator in the field. LOTO tag attached as close as possible to the connectible parts to prevent inadvertent re- connection. Multiple piece of equipment – Close air supply valve that feeds the entire solenoid box. 99 Gel Hoppers Why do we need them? The gel hopper is used to maintain a consistent flow of product to the granulator. The product is gravity-fed to the dosing screw, and is then pushed into the granulator through the action of the screw. How does the hopper work? The gel hopper is set to maintain a consistent weight of product on the dosing screw. This set point determines when more product should be added so that the feed is not interrupted. When the gel hopper dips below the set point, the automatic sequences within the DCS will begin the process of filling the gel hopper back up. The gel hopper weight is measured by the load cells. What Are Some Safety Concerns? Follow confined space procedures if you enter the gel hopper. What are the Troubleshooting Issues? If the load cells on the gel hopper are malfunctioning, the DCS will not have a correct weight to initiate sequences. 100  Pre-Grinder Why do we need Pre-Grinders? Some plants have pre-grinders and other do not. The primary purpose of pre-grinding is to tear the gel into smaller pieces so that the feed to the granulator will be consistent. If the feed to the granulator is not consistent, the flow through the dryer will be inconsistent. This will cause non-uniform drying. The pre- grinder is also used to post-treat gel, blend dust, and rework product. 101  Pre-Grinder How does it work? The pre-grinder tears the gel through the use of screws. The weight of the gel forces it against the moving screws. The screws tear away at the gel’s surface. The screws work best when the gel is hot; the colder the gel, the more difficult it is to pre-grind. The type of product also effects how well it grinds. Products like 934SH and 923SH grind very easily. Low UL products like VLM and BPM are more difficult to grind. Very high cationic product can be difficult to grind due to the stickiness of the product. If a product that is normally easy to pre-grind will not grind, there may be a problem with the gel. If the gel is hard to grind, the UL may be too high. If the gel lays flat, the UL may be too low. Gel enters the pre-grinder through the reactors. Once the gel has finished reacting and peaked out, it is held in the reactor to help reduce the un-reacted acrylamide monomer. Once the hold time has elapsed, the gel is dumped into the pregrinder. The gel is dumped by hydraulic cylinders for cubic reactors or by pressure in the tube reactors. When the gel is dumped, the screws should be turning forward. This helps to pull the gel out and reduces the strain on the gear motors. 102  Pre-Grinder How does it work? (Continued..) Once the gel has peaked and the hold time is complete, the pre-grinder should be prepared for dumping the gel. A grinding aid, Lubrhophos PK455, is added to many products to make the gel easier to cut. The first half of the surfactant is added directly to the screws before the gel is dumped. Once the screws have been coated the gel can now be dumped. After the gel is dumped, it is run forward for twenty minutes. After grinding for twenty minutes the gel is reversed. When the gel has been pulled back, the second half of the surfactant is added. Different products and plants have different treatment levels. This information should be on the dryer conditions sheet. Some products do not required surfactants because they pre- grind easily. Adding too much surfactant can cause the gel to become too fine and will plug the granulator and the fan. Surfactant helps to make the gel less sticky because the hydrophilic end of the surfactant attaches to the gel and the lypophilic end of the surfactant is oriented out. The lipophilic end keeps the gel from sticking to surfaces and to itself. 103  Pre-Grinder How does it work? (Continued..) The first half of the post-treatment is added when the gel is pulled back. The post- treatment is MBS for cationics and Sodium Sulfite for anionics. Be careful to check the bag for the right name. We also use Sodium Sulfate in blending. This will not work as a post-treatment additive. The post-treatment reacts with the monomer remaining in the gel. For the post-treatment to be effective, it must be evenly spread over the gel and then well mixed into the gel. For most products the monomer must be less than 1000ppm. For PWG products the monomer must be less than 500ppm. The second half of the post- treatment is added once the gel is returned forward. The gel is then allowed to pre-grind for another ten to fifteen minutes. The better the post-treatment is mixed into the gel, the more effective it will be at lowering the monomer. The amount of post-treatment will be listed on the conditions sheet and written on the pre-grinder board in the control room. Some products are not post-treated because it causes too great of a loss of UL. The technician may decide that the post-treatment should be added to the screws like the surfactant. 104  Pre-Grinder How does it work? (Continued..) Monosodium Phosphate is also added to the pre- grinder. The monosodium phosphate helps to reduce corrosion which can lead to specks in the gel. The monosodium phosphate is thrown at the same time the post-treatment is thrown. The monosodium phosphate is sometimes placed directly on the screws if there are a lot of specks. Monosodium Phosphate is added at 0.1% based on the weight of the gel. For example 6kgs of Monosodium Phosphate would be needed for a 6000 kg batch. Dust can be reworked in the pre-grinder. Dust is reworked by placing it on top of the gel and mixing in water. Enough water should be added to the dust to begin to turn it into gel. If dust is placed directly on the screws, a dam of gel should be left in the pre-grinder's feed and dosing screw. This will prevent dust and water from damaging the pre-grinder and granulator bearings. The dust is generally not reworked into sensitive product like PG products. Product and recycle can also be reworked in the pre-grinders in the same way. While the pre-grinder is in operation, the dryer operator should check to make sure the gel is grinding and moving evenly. Gel can tunnel out on some products when it is run forward for too long. Gel can also get hung up and not move uniformly. Some products require more attention than others. 105  Pre-Grinder Safety Concerns The main safety concerns in operating the pre-grinders are being injured by the turning screws, being overcome by nitrogen, and being injured by the chains. The pre- grinders are a confined space. A vessel entry permit must be completed before entering the pre- grinder. Extreme care should be used to make sure all screws are locked out, that the reactor cannot dump, and that the nitrogen from the reactor is not leaking into the pre-grinder. Extreme care should also be used when working near the chains, sprockets, or gear motors. The motors should be locked out, tagged out, and tested when working in this area. 106  Granulation Why do we need the Granulator? We need the granulator to reduce the gel to uniform particles. The uniform particles dry more evenly. The particle size is determined by the granulator screen size and also by pregrinding. The standard granulator screen sizes are 4.0mm, 4.5mm, 5.0mm, 6.0mm, 7mm, and 8mm. The smaller granulator screens improved drying by increasing the surface area of the particles while reducing the volume. Smaller screen puts more of the load on the granulator. The smaller sizes also reduce the load on the rollermill. The larger sizes are used to help reduce dust and reduce the load on the granulator. The correct granulator screen size for each product should be listed on the dryer conditions sheet per customer specification. 107  Granulation Why do we need the Granulator? (Continued…) The granulator we use was designed to recycle PVC pipe. It is made up of a heavy rotor with blades. There are two types of blades the fly knives which are attached to the rotor and the bed Bed Knives knives which rest in the frame. A 100hp motor turns the rotor and the product is forced between the fly knives and the bed knives. This cuts the gel. When the gel is the right size it is forced through the screen at the bottom of the granulator and is transported to the Fly Knives dryer by the granulator fan. 108  Granulation How can you tell if the blades need to be changed? You know it is time to change blades when you begin loosing the ability to push product to the dryers. This usually shows up on low molecular weight product like VLM or BPM first. The problem could be damaged blades. If the blades become extremely chipped they will no longer cut effectively. Blades can become chipped by metal passing through the granulator. This happens most frequently when recycling gel into the skip or the pregrinder. The granulator can also lose its ability to cut when the gap between the fly knives and the bed knives gets to large. The gap between the blades ranges from 8 to10/1000 inches. The gap must not exceed 25/1000 inch. If the gap increases above the maximum, the granulator will not work properly. The gap is adjusted by moving the bed knives outward toward New the fly knives. The gap increases as the blades wear down through use. Blade s 109  Granulation Before requesting that the blades be changed make sure the oil flow to the granulator is properly set. Check to make sure the oil spay nozzle is clear and the oil filter is not plugged. It is also smart to check the granulator for missing or loose belts. Check also for high granulator amps. Why do we use oil in the granulator? Oil and Alkamuls S-275 are used to help cut the gel. The S-275 is a surfactant which makes the gel less sticky and improves the knives ability to cut the gel. A surfactant is a surface active agent and is the name of the oils we use to help keep the gel from sticking. If too much oil and span are used the resulting product will make a cloudy solution and may not free flow. Too much oil can also cause re- massed clumps and even fires in the Blades need to be dryer. Too little oil and the gel will not grind. If the oil and S-275 flow is stopped Changed the granulator will clog. The oil S-275 mixture is sprayed into the top of the granulator. The spray nozzle must be periodically checked to make sure the flow rate is adequate. The correct percentage and flow rates are listed on the dryer conditions sheet. 110  Granulation Granulator Screens A hole in the granulator screen can result from wear and tear but most frequently results from metal damaging the screen. A hole can be detected by looking at the oversized at the dryer Kason or listening to for a louder than normal in the granulator fan. Proper installation the screen is another potential problem source. If the screen is not properly installed it can easily damage the blades. To change the granulator screens switch the granulator to "OFF". Lock-out/tag-out/test the breaker following plant procedures. Then unscrew the clamps which hold the screen cover plate in position. Remove the plate. Next loosen the lock nuts and unscrew the studs on either side of the cutting chamber. Inspect the studs if the tips are worn or damaged, they should be replaced. The screen may now be removed by screwing the pull handles into the nuts welded to the end of the granulator screen and sliding the screen out. Once the screen has been removed, consult the Plant Conditions Form or see the Supervisor for the correct screen size to be installed. When running post hydro we use a 10mm screen on GR1 and a 6mm on GR2. 111  Granulation Granulator Screens Once the right screen has been selected, make sure the screen 1 2 support in the granulator is free of product. Clean the support if necessary. Slide the new screen into the granulator. Screw in the studs on either side of the cutting chamber. 5 6 Tighten the studs in the order shown in the following diagram: 7 8 Check that the studs are over the screen. If the screen is level with any stud or over any stud, unscrew that stud. Open the hopper door, and using a bar, apply pressure to screen. Screw the stud in and 3 4 check again. If this does not work call maintenance or the supervisor on duty. Screen Plate Cover The stud should securely hold the screen down. If the screen is loose under the bolts call maintenance or the supervisor on duty. Once the side studs are properly installed, slowly turn the rotor. If the rotor knives touch the screen at any point, remove the screen. Mark the defect, and obtain a new screen. Notify maintenance that the damaged screen needs replacing. Repeat the above steps for the new screen. When the rotor turns freely, tighten the lock washers, close the hopper door, replace the cover plate and tighten the screws. Remove the lock out lock and switch on the breaker. The granulator is now ready for use. The screen change should be noted in the dryer logbook. 112  Granulator Trouble Shooting The primary maintenance concerns for the granulator are replacing blades and bearing failure. Blades fail if metal is allowed to go through the granulator. If the sound of metal is heard in the granulator, turn off the granulator immediately. The metal should be located and the blades checked for damage. Metal can enter the granulator from recycling, damaged screws or failed bearings. The blades will also need to be replaced if there is excessive wear. The optimum blade gap is 8/1000 to 10/1000 of an inch, If the gap between the blades is more than 30/1000 of an inch, the blades should be adjusted or changed. Bearings will fail if they are not greased appropriately or if they are damaged by water, dust or dry product. The first sign of blade wear is poor chopping and slow flow through the granulator. If the granulator is constantly shutting off the problem may be a loose safety switch on one of the doors. If the granulator will not start the problem may be a bad motor or switch gear. Another granulator problem could be gel build up on in the discharge hopper. This could result from the liner being worn, not enough oil or from product characteristics. 113  Granulator Safety Concerns The granulator can be very dangerous if it is not operated correctly. Extreme caution must be used when working on or around the granulator. The granulator has safety switches which are designed to stop the granulator when the doors are opened. These safety switches are not designed to replace lock out, tag out, and test. When any of the doors or hatches to the granulator are opened the granulator must be locked out, tagged out and tested. When cleaning the granulator, gloves should be worn to protect the hands not only from the gel but also from the blades. An oil resistance coverall should also be worn. The blades are sharp and can cut even when the granulator is locked out. 114  Granulator Safety Concerns The granulator can be very dangerous if it is not operated correctly. Extreme caution must be used when working on or around the granulator. The granulator has safety switches which are designed to stop the granulator when the doors are opened. These safety switches are not designed to replace lock out, tag out, and test. When any of the doors or hatches to the granulator are opened the granulator must be locked out, tagged out and tested. When cleaning the granulator, gloves should be worn to protect the hands not only from the gel but also from the blades. An oil resistance coverall should also be worn. The blades are sharp and can cut even when the granulator is locked out. 115 Granulator Oil Spray Nozzle Attach the Oil supply to the liquid port. Attach the Air supply to the air port. Proper air pressure is critical to proper atomization of the oil. Installed in the top of the granulator to enable the system to run a lower oil flow rate. 116 Granulator Oil Spray Nozzle (cont’d) See PAM-03-205 for complete instructions how to remove, clean, and replace nozzle. Lines should be properly identified/marked/labeled before disconnection from the nozzle. This is to ensure that they the correct supply line is connected to the corrected nozzle port. This is a primary responsibility of OPR personnel involved with permitting the job. Lines should be properly identified/marked/labeled after any work on the granulator or its oil nozzles. This is a primary responsibility of OPR personnel involved with permitting the job. The air and oil ports should be clearly marked/ID’ed prior to installation. If unsure, consult a SME. 117  Oil Tank The granulator will not work if the oil and surfactant mix is not applied to the gel. The gel will bog down the granulator almost immediately once the oil/surfactant flow stops. If this happened the plant will be on hold until the granulator can be cleared. 118  Oil Tank How does it work? The oil tank is where we mix the oil and surfactant. A surfactant is type of chemical that is used as a surface active agent. They are made up of oily molecules that have a water loving end and an oil loving end. The water loving end sticks to the gel and the oil loving end creates a non- stick surface on the gel. The surfactant we currently use is S-275. The oil we currently use is LPA210. The oil tank is also how we feed oil to the granulator. Once the oil/surfactant mix is right, it is feed to the granulator by means of a micro- pump and tubing. The oil is sprayed into the granulator through a spay nozzle to get a good coating. 119  Oil Mixing The oil needed for the mix is supplied by a pump from the tank farm. The amount of S-275 needed for each product and plant is found on the dryer condition sheet. The S-275 is supplied in totes and is measured volumetrically. As with any material supplied via tote, it is important to compare the amount of S-275 added via the flowmeter versus the amount visually determined by recording the initial and final heights in the totes. Air passing through some flowmeters can be registered as actual liquid which can lead to an inaccurate measurement of the amount added. The tote should also have a minimum liquid height equal to about 15” ( up to the second rung of the tote cage). See “One-Point Lesson - Charging S-275 into Oil Tanks.” A density test is used to determine the how much S-275 needs to be added to the oil in the tank. 120  Past R-9 Screw Problems The gearboxes for the R-9 screws should be the same distance from the side of the tank. If a gearbox protrudes too far from the side, gel transfer efficiency can be lost and damage to the screw and supports have occurred. The alignment of all the screws should be compared to each other as part of operator rounds. 121  Oil Tank Safety Concerns The oil surfactant mixture is a skin irritant. Contact with this mixture should be avoided. The mixture is also combustible. Care should be used when performing hot work around the tanks. 122  Span/Tween 80 Additive This additive coats the Vazo 64 to keep it in a slurry form to allow a good transfer to the reactor. 123  Surfactant Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming agents, and dispersants. 124 When do we need to pull Granulator Samples? When we fail any kind of QC Result and the product becomes non-conformed Blend – You must pull a Gel Sample and Dryer Sample This is what tells us we have off-grade product 125 How do we know a Product is Good for Sale? Each product to be packaged must be Each product will undergo a set testing criteria and is listed here: receive a final “C” 126 Rx to S1 Air atomized oil Granulator Automated injection into transport fan block valve Granulator Screw on/off controlled by RX gel hopper weight Gel hopper on Cyclones to weigh cells reclaim emissions from Dosing Screw S1 To Stack S1 Dryer S2 Dryer S1 Drain screw S1 dryer on automatic weigh cells speed varies to control weights 127  Now lets reduce the particle size of the polymer using a Granulator Our Granulators are designed to eat fridges, so our equipment works very well with polymer So how do we improve the Granulator performance? – We spray a mixture of air/oil to the polymer to soften it for cutting Lower molecular weights product tend to be “sticky” and not cut as well so we need to monitor our granulators for build- up. 128  Fans Why do we need Fans? We use fans to move air. Fans can be used to move air to cool us off or vent hot air out through the walls. Fans can also be used to transport gel from the granulator, or transport product in the dry room piping. Fans are used to create fluidization and to dry the product in the dryers. They are used to vent fumes from the reactors, pre-grinders, and the skip. 129  Fans How do they work? Axial Flow Fans can be either axial flow fans or centrifugal fans. In axial flow fans the air blows straight through the fan. An example would be a floor fan or a wall fan. In centrifugal fans air comes into the front of the fan and exits at 90 degrees through the top. In axial flow fans the turning of pitched blades causes the air to move through the fan. In centrifugal fans the turning of an impeller pulls air into the fan. The specially shaped housing causes the air to build pressure by centrifugal force. The air then exits out the top of the fan. In centrifugal fans the impellers can be either closed or open. Closed impellers have a plate Centrifugal Fan on either side of the blades. This fan impeller is used to move air alone. Examples of a closed impeller type fans would be dryer fans and DCE fans. An open impeller has a plate on only one side of the blades. Open impellers can move both air and powder/gel. An example of this type fan would be a granulator fan or a transport fan. Closed Open Impeller Impellers 130  Fans In The Plant Granulator Fans: Move product from the granulator to dryer 1. On Post Hydro these fans can move product to the M1 are M2 blenders. 2. LP3 dryer 1 cyclone fan moves product from the cyclone to dryer 2. 3. Post hydro vent fan pulls a vacuum on the post hydro system and sent the ammonia to the stack. 4. Dryer burner fans that forces air and heat into the dryers. 5. Dryer combustion fans that are used to get the correct air mixture for the burner. 6. DCE fans are used to pull a vacuum on the system to convey product. 131  Fan Troubleshooting Since fans operate at fairly high speeds the fans have to be in balance. If not the fans will shake apart. An out of balance fan could be the result of product built up on the impeller. Because of the speed of the fan, the condition of the fan bearings has to be watched closely. Check to make sure the bearings are securely mounted onto the housing. Also check that the motor in securely fastened to the motor mounts. A worn impeller can also case vibration. This damage can be the result of the impeller being continually sandblasted by the product as it blows through the fan. This sandblasting effect can also create holes in the fan housing To get good suction the fan belts have to be tight. Missing fan belts can also cause poor suction. Fans can plug if the suction is poor or if they are over- loaded. 132  Fan Troubleshooting – High Amps/Tripping Look for anything that would cause the fan to work harder. These items include: Clog in Piping Bad Motor Windings – Have the motor megged by an electrician Impeller/Shaft Movement – Usually noticeable by noise and vibration 133  Fan Troubleshooting – High Amps/Tripping (cont’d) Look for anything that would cause the fan to work harder. These items include: Bad Motor Bearings – Usually noticeable by noise and vibration – Potentially may not hear or notice vibration but the bearings may be extremely hot. Bad Fan Bearings – See items under “Bad Motor Bearings” 134  Fans Safety Concerns Open Impeller-Cyclone The main safety concern with using fans is getting hands and fingers struck by moving fan blades or Fan impellers. This could cause very serious injury. The fan should not be operated if it is not properly sealed or guarded. When working on a fan it should be locked-out, tag-out and tested. Fans can still move even if locked-out. Air moving in the line from another source can cause the blades or impeller to continue to turn. Make sure the impeller has stopped moving before beginning any work inside the fan. Fans in line with other equipment can cause this equipment to continue to move if the fan is not locked out. An example would be flash dryer paddles. Belts and pulleys can also pose safety concerns. If tools, hands or fingers are caught in the pinch point between the belts and pulleys serious injury can result. Motors are also potentially hazardous due to the risk of electrical shock. Over heated fan bearing can also cause fires. The heat from the bearing can ignite the powder built-up near the bearing. Keeping the bearings serviced will help to prevent these types of fires. Closed Impeller-DCE fan 135  Fan Belt Tension Device Equipment maintenance will be using when checking the belt tension on all motors. 136 Belt tensioner and Laser Alignment When working with the belts on any equipment in Powders, the craftsmen should always have the proper tools to do the job. If changing out a Granulator, Fan, etc. the alignment tool should be used to assure the pulleys are in correct position / properly aligned. Once installing belts for any reason (e.g., due to equipment replacement or due to just changing the belts due to belt wear), the belt tensioner needs to be used to get the tension to the manufacturer’s specs. SAP has all the settings needed so that the craftsmen is not in the dark on what the tension should be. In the past they have not used these tools and it has led to premature belt failures due to incorrect installation. With the tools we now have, we should increase our reliability. When writing permits for these jobs, the operator should have the conversation with the craftsmen to ensure that they are using these tools. If MNT is not using the tools for a job in your area, you must have your supervisor contact the contract MNT supervisor and determine why the correct tools are not being used. o Check to see if these tools are noted in the work order’s instructions or scope of work. o Write the requirements into the safe permit’s scope of work. Example: Replace belts and check alignment and tension with special tools o Ideally, the area operator should be present at the time of these maintenance tasks to witness the use of these two tools. As part of improving job knowledge, all operators should immediately seek to witness these tasks being performed. 137 Laser Alignment The laser alignment should be used on all equipment that has pulley’s. Craftsmen has an easy job of alignment when using laser. 138  Drying Why do we need to Dry? Funny the way it is, we add water in polymerization and then we remove it in drying. We add the water in Poly because it helps to absorb the exothermic heat of reaction. If the water was not added to the batch, the batch would boil out of the reactor. A batch boils out when the water in the gel turns the vapor near 100 ˚C. The batch at first swells but can boil out if the rate of vapor formation is rapid enough 139  Drying Where does the water come from? Some of the water we add directly for heat absorption, the rest of the water comes from the raw materials. Water makes up about half of the acrylamide solution that is charged to the dissolution tanks. Dry acrylamide is not used because it sublimes to vapors and makes it more hazardous to handle. Cat monomer, when used, also contains some water. The caustic added to anionic batches adds more water because it is a fifty percent solution. The remainder of the water in the batch comes from neutralization. Dry polymer fits many applications We sell dry polymer because it is concentrated polymer. Most anionic polymer is about 88% dry content. Cationic poly will have an even lower moisture content. This makes it cheaper to ship especially internationally. Also for customers who use large quantities of polymer powder is the way to go, because it makes storage easier. Emulsions and Liquids are frequently easier to handle and make down but more expensive to ship. Dry Polymer also has a longer shelf life than Emulsions or Liquids. Powder Polyacrylamide is used in wastewater treatment, water treatment, paper manufacturing, mining, sugar processing, oil drilling and enhanced oil recovery. 140  Drying The problem of Drying? Good Solubility Polymer gel is usually about 70 to 60 percent water, high cationics will have less water in the gel. The water content has to be reduced to 12 percent or less for the product no to clump in the package. The problem is it takes a lot of heat to remove all that water and all that heat can damage the product. If the polymer sees too much heat for too long the solubility of the product degrades. One of the characteristics of polyacrylamide is that it is a long straight chain and is soluble in water. If the polymer is over dried it loses its ability to dissolve in water. The first sign of over drying is low moistures, then swollen points, then small cross-links and finally large cross-links. The polymer tends to branch first and then cross-link. The solubility can deteriorate from clear screen, to points that can be easily counted, to more than 20 points, to half- screen covered, screen covered, and bad filtration. Specific customers and industries have differing solubility quality standards. The goal is to dry the product without significantly reducing the product quality due to poor solubility. Over drying the product can lead to filter Bad Solubility ratio issues. Bad solubility can also be a polymerization problem. When the gel is analyzed it frequently will have small cross-links. These can be from cross-linking agents in the raw materials. Poor quality monomer can also cause cross-linking. Additives have been known to create cross- links. Another common problem is exceptionally high UL, when dried the product will cross-link even with mild drying conditions. Batches that auto-initiate can be cross-linked due to high UL. 141  Drying Pre-grinder Sample Particle size and drying The gel particles dry best with a surface to volume ratio of about 1. Pre-grinding and/or granulation are used to get large blocks of gel down to particles small enough that will dry effectively. To get even drying the gel particles need to be in continual contact with air. The more thoroughly the air surrounds the individually particles the better and more even the drying. Granulator Sample If particles are too big, it will be hard to dry the center the particle. If the particles are too small, the particles will dry too fast and can crosslink. 142  Drying Dryer Types There are three powder dryer systems; the original rotary dryers, Original Rotary the fluidized bed dryers, and the new rotary dryers. Included within these Dryers systems are: flash dryers, post dryers, after coolers, fines dryers. The dryers were designed to optimize the removal of water while minimizing damage to the product. The dryers were also designed to Fluidized Bed minimize the cost of construction and Dryers minimize operating cost. New Rotary Dryers 143  Drying Original Rotary Dryer The original rotary dryers use a combination of air flow and mechanical action to fluff the product for drying. The air pressure is created by the dryer fan. This pressurized air moves from the fan through the wind box and enters the dryer through air strips or air injectors. The air injectors force the air down and into the product. The product is fluffed by mechanical rotors with the assistance of the air. These rotors create mechanical agitation of the product. The combined action of the air and the rotors allow the product to be dried evenly. The product exits the dryer through an outlet feeder screw. The level is controlled by the amp reading on the rotor’s motor. 144  Drying Fluidized Bed Dryer The fluidized bed dryers use air alone to fluff or fluidize the product. The air blows from the fan through the wind box and enters the dryer through bubble caps. The air causes the powder to look like a fluid as it moves through the dryer. The product is dried very evenly do to this fluid motion. The product exits the dryer by means of a gate at the end of the dryer. The height of the gate controls the level inside the dryer. The product exits the dryer by overflowing the gate. 145  Drying New Rotary Dryers The new rotary dryers are very much like the original rotary dryers. The air leave the fan, passes through the wind box and enters through air injectors. The pressure transmitter for the fan is located in the fan wind box. Paddle style rotors fluff the product. The air and rotors work together to evenly dry the product. The level is controlled in these new dryers by load cells. The product exits the dryers through exit screws which are similar to the outlet feeders. The product in the new rotary dryer has a chance of remass if the rotor shuts off for a period of time. The dryer pressure transmitter is located in the top side of the dryer shell. The dryer product temperature probe is located in the bed of the dryer that holds the product. 146  Drying Flash Dryer The Flash Dryer operates at high temperatures, usually 170-180 degrees C. Because of the high temperatures the dryer is able to remove about 10-15% of the water off in about 10 minutes. The product is not damaged by the high heat because the product is very wet and it only stays in the dryer for a short period of time. Post Dryers and After Coolers Post dryers and after coolers are used to finish the drying process under cooler conditions than in dryer 2 or the second part of the dryer. This is needed because when the product is dried at too hot a temperature the product will be too hot to bag out. If the product is bagged out at temperatures above 35°C it can re-mass in the bags. Dust and Fines Dryers Dust and fines dryers are used to dry dust that has been removed from the process. It is easy to over dry dust because the particle size is so small. It is also easy for the dust to blow out of the stack again because the particle size is so small. The fines dryers are use to prevent cross- linking and to keep the dust within the process. 147  Drying The Theory Evaporative Drying (Dryer 1) There are two main phases in drying with an intermediate phase in between. The first phase is called evaporative drying. In this phase of drying the particle is wet. The heat from the burners evaporates the water from the surface of the particle. More heat can be used in the flash dryer, in part 1 or in dryer 1 because the water protects the particle. This is like putting two pots on a stove, one with water and the other without water. When the pot with water is heated, the water boils. The temperature of the pot will not exceed the boiling point of the water, 100 C. The pot that is empty will eventually heat up to the same temperature as the burner. The water protects the first pot from getting as hot as the second pot. This same principle protects the polymer in the first phase of drying. Evaporative drying occurs from about 70% moisture down to about 25% moisture. In this range the product still feels wet. Intermediate Drying In the range of about 24% to 22% there is an intermediate phase. In this phase there is still some water on the surface of the particle but most of the water is being pulled from inside the particle. Diffusional Drying (Dryer 2) Below 21% moisture the drying phase is called diffusional drying. In this phase of drying the water is not longer on the surface but is being pulled from inside the particle. In this phase the particles begin to heat up because there is no water on the surface to protect it. In part one the burner is hotter but the product temperatures are relatively lower than in part two where the burner is lower but the product temperature is hotter. The drop in moisture in the evaporative phase is large from 70% to 25%. In the diffusional phase the drop is less, from 21% to 11% or below. The greatest chance for cross-linking and solubility problems is in part two or dryer two. The phases of drying are important. The flash dryers works because of the evaporative drying. The product can handle the high temps because of the water. Without the water the product would cross-link at such high temperatures. Part one and dryer one use this same principle. Part two or dryer two should be watched closely when solubility is important because the product can be easily over dried in the diffusional phase. Cool Down (Dryer 3) A third phase in drying is cool down. Some plants have a third section that allows the product to cool in the dryer and some plants have a post-dryer. The purpose of cool down is to lower the temperature of the product. If the product is bagged out at too high a temperature, it can re-mass in the bags. Cooling the particle helps to prevent this re-mass from occurring. This cool down is especially needed when the temperature in the flash dryer and part one are very high. Understanding the phases of drying can assist in setting good drying conditions and to prevent solubility problems. 148  Drying Temperature The main variables that can be controlled in drying are feed rate, level, airflow, and temperature. The feed rate and level are linked together as residence time. The airflow is related to dryer pressures. Temperature is the most effective means to control drying. The dryers are direct fired natural gas dryers. The heat comes from air heated by the gas burners. The temperature in the dryer is controlled by adjusting the amount of gas supplied to the burners. The burner temperature in the flash dryers is usually set at about 170 - 180 ˚C. The burner in dryer one is set about 140 - 155 ˚C. The burner in dryer two is set at about 120 - 80 ˚C. The gas flow is controlled by two valves. One valve controls based on the burner temperature set point. The other valve controls based on the product temperature set point. In older plants where the dryer one burner is limiting, the dryer is controlled by maximizing the burner and forcing the dryer one product temperature to reach for its set point. In dryer two the product temperature is used to control drying. Maintaining a constant product temperature in dryer two is critical because the product can be easily over dried or under dried. Over dried product will have poor solubility. Under dried product can clog up the grinding and screening equipment in the dry room. If the burner is used for primary control or if the product is used for primary control, the burner must be set so that it does not spike. This spiking happens as the burner responds to changes in the product temperature. Dramatic changes in the burner temperature can cause over drying. Preventing this spiking is especially important with sensitive products. The way to avoid spiking is to set the burner so that it is well matched to the product temperature. 149  Drying Temperature (Continued..) The location of the temperature probes is also noteworthy. The burner probe is in the wind box and gives an instantaneous reading. The product temperate is in the dryer bed and gives a point in time reading. The temperature in the dryer may look correct but it will not show a slug of over dried or under dried product before the probe. Therefore it is essential to run the dryers steady and evenly. It is especially imperative to do this in dryer two. 150  Drying Level The level of the dryer is one of the variables we can change but usually do not. The level in combination with the product feed rate controls the residence time. The higher the level the longer the product stays in the dryer, the lower the level the shorter the time the product stays in the dryer. The average resident time is close to the time it takes to load or down load the dryer at the standard feed rate. For most products we keep the level constant. In the original rotary dryers if the level gets too high the airflow is reduced, this reduces fluidization. Reducing the fluidization hurts drying efficiency. If the level is too low in the rotary dryer, you can blow product into the cyclone system. In the rotary dryers the level should be covering the rotors with a V shaped valley in between the rotors. If the rotors are showing the level is too low. If the level is flat or bulging in the center the level is too high. The level in the rotary dryers is measured by the amp load on the rotor gear motors. The level should be visually checked because the amps reading can change if there are mechanical problems with the rotor, the bearings or the gear motor. In the fluidized bed dryers the air will change as the level changes. But we still try and keep the level constant. The level is controlled by the gate setting. If the seal is bad on the gate it will be difficult to hold the correct level. The adjustment on the gate needs to be checked occasionally to make sure it is accurate. Too high a level in the fluidized bed dryer can cause re-mass. Too low a level can transport product int