Basics of Mills PDF
Document Details
Uploaded by GentleViolin
Tags
Related
Summary
This document provides a basic overview of sugar cane mills, covering topics such as sugar cane composition, parts of a sugar cane plant, and various processes involved in extracting juice. The focus is on the practical aspects of the operations and the different factors involved in quality sugar extraction.
Full Transcript
MILLS SUGAR CANE (Saccharum officinarum) Sugar cane are perennial tropical giant grass belonging to the genus “saccharum”. They have stout, jointed fibrous stalks 2-6 m tall and sap rich in sugar. Sugar cane is cultivated...
MILLS SUGAR CANE (Saccharum officinarum) Sugar cane are perennial tropical giant grass belonging to the genus “saccharum”. They have stout, jointed fibrous stalks 2-6 m tall and sap rich in sugar. Sugar cane is cultivated in over 100 countries and the amount of sugar from sugar cane is approximately 6 times higher than of beet sugar. COMPOSITION OF SUGAR CANE SUGAR CANE 75% 25% WATER SOLIDS 13% FIBER 12% SOLUBLE SOLIDS 10.5% 1.5% SUGAR NON-SUGAR 0.7% 0.7% 9.8% 0.8% INVERT MINERAL SUCROSE ORGANIC NON-SUGARS SUGAR MATTER 0.5% 0.2% 0.1% UNIDENTIFIED NITROGENOUS SUBSTANCES NITROGEN FREE SUBSTANCES SUBSTANCES 0.03% 0.02% 0.06% 0.14% STARCH, WAX, CARBOXYLIC PROTEINS AMINO ACIDS FATS, ACIDS PHOSPHATIDES Source: Industrial Utilization of Sugar Cane and its Co-products. P.J. Manohar Rao Parts of a Sugar Cane Plant Tops FOR A TYPICAL PHILIPPINE CANE VARIETY CLEAN STALKS - Stalks cut just above the ground and topped below the level of the cane top - Have internodes and soft centers with nodes in between - Free of adhering leaves and other foreign materials - Not dried out - 15-24% Brix - 78-90% Purity - 11-14% Fiber - 13,000-18,000 ICU - Considered as ideal canes for milling Clean Stalks + Good Factory Operation = Optimum Sugar Extraction and Recovery Source: Sugar Cane Milling Manual Vol.1 FOR A TYPICAL PHILIPPINE CANE VARIETY CANE TOPS - Part of the stalks above the natural breaking point including all the green leaves and sheaths attached to that part of the stalk - Natural breaking point is where the stalk will break fairly easily when bent manually - 7-11% Brix - 26-40% Purity - 8-16% Fiber - 32,000-100,000 ICU If there are a lot of tops included in milling, the factory recovery will be below optimum since tops have low purity juices and high color juices. Source: Sugar Cane Milling Manual Vol.1 FOR A TYPICAL PHILIPPINE CANE VARIETY CANE TRASH - Leaves and sheaths delivered with the clean stalk - 2-5%Brix - 14-32% Purity - 28-33% Fiber - 356,000-640,000 ICU - Reduces Extraction since leaves and sheaths have practically no sucrose and have very high fiber content Source: Sugar Cane Milling Manual Vol.1 FOR A TYPICAL PHILIPPINE CANE VARIETY EXTRANEOUS MATERIALS - Any solids delivered with the cane excluding leaves and sheath - Examples: - Dried out stalks or deteriorated canes - Mud - Weeds - Roots - Adhering soil - Rocks - Reduces Factory Recovery as these materials have no sucrose - Source of Dextran - Unnecessary wear on equipment - Clarification problems Source: Sugar Cane Milling Manual Vol.1 MILLS BASIC PROCESS FLOW DIAGRAM Cane Cane Handling Extraction Preparation BASIC PROCESS FLOW DIAGRAM CANE HANDLING CANE PREPARATION EXTRACTION CANE HANDLING MAIN OBJECTIVES To receive and unload the canes from the hauling units To convey the canes to the cutting and/or shredding units in a continuous and regulated manner Prior Cane Sugar Cane Truck Scale Handling Measures the gross and tare weights of trucks Uses Load cells How do these load cells work? The load cell converts a load or force acting on it into an electronic signal. This electronic signal can be a voltage change, current change or frequency change depending on the type of load cell and circuitry used. Where would this load or force come from? A force is an interaction between two bodies or between a body and its environment. A force is a vector quantity, with magnitude and direction. Resistive load cells work on the principle of piezoresistivity. When a load/force/stress is applied to the sensor, it changes its resistance. This change in resistance leads to a change in output voltage when a input voltage is applied. Capacitive load cells work on the principle of change of capacitance which is the ability of a system to hold a certain amount of charge when a voltage is applied to it. Example: Capacity: 80 tons Cane CANE FEEDING Handling LEVELER TABLE GANTRY FEEDING CARRIER The cane handling station setup looks like this. There are truck tippers, dumper, and a gantry DUMPER area with a travelling crane. CANE CANE KICKER KICKER From the gantry, bundle of canes are dumped at the feeding table. From the tippers, the canes are CANE dumped into the cross conveyor and ultimately, LEVELER the canes from the feeding table and the cross conveyor converges to the feeding carrier. CROSS CONVEYOR TIPPER 2 To facilitate a regulated and even/smooth flow of canes from one conveyor to another, there are TIPPER 1 cane levelers and cane kickers. SAMPLE LAYOUT Cane Handling Cane Truck Dumper/Tipper A platform that tips trucks end-wise Cane Handling Gantry Crane Canes are unloaded per bundle via steel cables and a crane Type: Travelling crane Motion: Lateral direction Cane Handling Cross Conveyor A moving apron in a pit which conveys the cane to the Feeding Carrier The apron is steel slat plate-type This conveyor is an inclined lateral table, rising towards the front so that it discharges the cane into the carrier high enough, as not to interfere with the cane being conveyed by the Feeding Carrier. Also: Side Cane Carrier, Auxiliary Carrier, Cross Cane Carrier Cane Handling Feeding Carrier A moving apron in a pit (much deeper than the cross conveyor) which conveys the cane to the First Cane Carrier The only carrier that is not inclined The apron is steel slat type, steel roller chain. Cane Handling Cane Leveler A contra-rotating equipment needed to level or shave off the irregular height cane in the table or carrier BACK Cane Handling Cane Kicker A rotating shaft designed to ensure that the cane is being pushed down to the next carrier rotates along the same direction as that of carrier Also: Tumbler CANE PREPARATION MAIN OBJECTIVES To reduce the stalks of cane into shredded tissues with the maximum broken cells but maintaining a reasonable length of fiber to facilitate feeding and extraction of juice To feed extraction station with continuous, regulated and even flow of shredded canes Cane Preparation The cane mat travels from the 1st cane carrier to the 1st cane cutter then goes to the 2nd cane carrier to pass through the 2nd cane carrier until it goes into the shredder. Cane Preparation Note: These pics were taken on a random Monday shutdown. The cutters are already in poor condition. The shredder hammers were being built up. Cane Preparation Cane Cutter Clearance and Blade Spacing Clearance, in Spacing, in 1st Set 6 - 14 1.5 – 2.0 2nd Set 1.5 - 3 0.75 – 1.0 Cane cutters are blades arranged on a rotating shaft designed to cut the cane stalks in smaller pieces prior to their entry to the shredder. The difference between the 1st and the 2nd set can be seen on the cutter clearance and their blade spacing. Cane Preparation Examples of Cane Cutters Single-bladed Knife Unit Double-bladed Knife Unit Cane Preparation Cane Shredder To tear open and disintegrate the cane cells How? By forcing the pieces of cut cane to pass through a very narrow space, and as the cane passes through this area, the cane is then blocked one side (by an anvil), and the rotating hammer will strike it on the other side. Why? Tissue of cane cells is very resistant: simple crushing between rollers, even under very high H pressure, is not sufficient to break all the cells and A extract the juice. So when the cane cells are M sufficiently torn open and disintegrated, juice is M liberated, making it more accessible and more easily Sugar Cane E extracted. R ANVIL ANVIL Cane Preparation Examples of Cane Shredders Walkers Heavy Duty Shredder Tongaat Heavy Duty Shredder Fives Cail and Fletcher Heavy Duty In-Line Shredder In-line shredder does need any preparatory equipment (cane cutters/knives) Cane Preparation Tramp Iron Separators Because of the nature of the preceding processes and the varying conditions of cane deliveries, a very important auxiliary installation (tramp iron separator) is needed to protect the next equipment from tramp iron. Tramp Iron - stray metallic particles or objects (pieces of knife-blades, sling-hooks, broken pieces of slings, monkey wrenches, bolts and nuts Suspended Magnet Separator MONITORING AND DETERMINATION OF PERFORMANCE CANE PREPARATORY EQUIPMENT CANE PREPARATION INDEX (CPI) Measure of the extent of rupture of cells in prepared canes Typical PI values range from 80% to 94% This established by mixing the cane and water for a preset time and measuring the concentration of the dissolved solids in the extract. B (Brix by leaching) Preparation Index = B2 (by disintegration) EXTRACTION MAIN OBJECTIVE To extract the optimum juice content in the shredded or prepared cane by successive squeezing producing bagasse that has minimal moisture content TOP VIEW Extraction SIDE VIEW Extraction CONVENTIONAL MILL CONVENTIONAL 3 ROLLER MILL Rollers compress the TOP prepared canes to squeeze ROLL the juices from the cane FEED ROLL DISCHARGE ROLL mat and expel the bagasse The plate between the feed and the discharge roll is called the trash plate Extraction MILL CONFIGURATION As the sugar processing industry progressed, the mills roller setup have also changed. TOP ROLL UNDERFEED ROLL The 4 roller mill has an additional roller on top of the FEED DISCHARGE ROLL ROLL feed roll and is called the underfeed roll. The underfeed roll helps for 3 ROLLER MILL 4 ROLLER MILL better feeding of the bagasse. Extraction MILL CONFIGURATION Five roll mills were Six-roller mills have developed to enhance an underfeed roll PRESSURE feeding and throughput. FEEDERS positioned on the PRESSURE In this configuration, the FEEDERS pressure feeder to UNDERFEED three roll mill is ROLL give a better preceded by a two-roll geometry of entry, pressure feeder running especially with at a higher speed than gravity (Donnelly) the mill rolls. The two chutes. roll pressure feeder is any of the following: toothed pusher rolls or light duty 5 ROLLER MILL 6 ROLLER MILL feeders medium duty roll heavy duty roll Extraction MILL GROOVING Originally, mill rollers were smooth. However, the capacity of a mill with smooth rollers is much less than that of a mill of the same dimensions, but with grooved rollers. Furthermore, the grooved rollers break up the bagasse more completely, and thus facilitate the extraction of the juice. Extraction MILL GROOVING V-Groove or Radial Dimension: Pitch – 6mm to 76mm Angle – 35˚ to 55˚ V-Groove Profile Extraction MILL GROOVING Pitch – distance which separates the axes of two successive teeth Height (depth) – distance from the top to the bottom of the teeth, measured perpendicular to the axis of the roller V-Groove Profile The pitch and the depth is used to specify the grooving. Ex.: grooving of 10 x 13 mm means a grooving that is 10 mm deep and 13 mm pitch. Extraction MILL GROOVING V-Groove or Radial Steep-angled grooves – usually about 35˚ angle, provide better drainage and extraction due to lower reabsorption, can also decrease bagasse moisture by 3% Coarse or large grooves – 45o to 55o and have more than 38mm pitch, used to further shred and tear the cane, generally found in the 1st to 3rd mills Small grooves – no more than 38mm pitch, effective for juice drainage and work better with well-prepared canes, found on the 4th to the last mills Extraction MILL GROOVING Messchaert Groove Also known as “juice grooves”; used to facilitate draining of extracted juice. These are usually provided in the feed rollers Dimension: width of 3 - 6.5 mm, depth of at least 20 mm but generally 25 mm, pitch is a multiple of the main grooving There is no advantage to be obtained by making them wider; the pressure succeeds in forcing bagasse into Messchaerts which are too wide, and drainage is less effective. Extraction MILL GROOVING Messchaerts may be provided in two ways: (1) By eliminating a tooth and locating the Messchaert in the position of the tooth eliminated (2) By leaving all the teeth, and cutting the Messchaert between two teeth The latter system has the advantage that it does not lose a tooth, and consequently avoids creating a zone of lower pressure in the layer of compressed bagasse. On the other hand, lateral drainage of the juice is not so easy, and the teeth next to the Messchaerts have a greater tendency to fracture along the line ab. Thus the second system is reserved for coarse grooving in which the width of the tooth compensates for the proximity of the Messchaert Extraction MILL GROOVING At the feed roller, it is in the zone AB that the bagasse undergoes the maximum pressure, and the juice is extracted. TOP ROLL But this juice has only two ways of escape: forward with the roller, beyond the trashplate to point D, or backward in the direction of the DISCHARGE point C. FEED ROLL ROLL In either direction, it encounters a thick layer of bagasse, already compressed, so the probability of reabsorption of the juice into the bagasse is high. Action of Messchaerts at the Feed Roller Extraction MILL GROOVING Chevron Grooves Cut on the v-groove rollers to aid in gripping the bagasse for better feeding Extraction MILL GROOVING Lotus Roll Perforated Rolls The drilled holes at the bottom of the grooves are connected to longitudinal cylindrical drains that terminate on the side of the roll. Used to enhance drainage (top rolls); Suited for the 1st and 2nd mills Extraction Variation of Grooving The size of the grooves generally decreases from the first to the last mill. Why? a.The bagasse becomes finer and finer as it proceeds from the crusher to the last mill. It is logical to proportion the grooving to the size of the bagasse particles which it was designed to handle. b.One of the objectives of grooving is to break up the bagasse to facilitate the extraction of juice. It is in the early mills, therefore, that the greatest disintegrating effect must be sought (hence the coarsest grooving), in order that the later mills should profit from it. Extraction Criteria for Choosing Roll Grooves Fine Grooves 7 mm to 38 mm DIMENSIONS PITCH Rough Grooves 56 mm to 76 mm Fine Grooves Better drainage PITCH Rough Grooves Better tearing action PERFORMANCE Small Angle Better drainage GROOVE ANGLES Large Angle Less wear Pitch of 76 mm for 1st two mills, then 26 Knifed Cane mm, groove of 40˚ to 55˚ QUALITY OF CANE PREPARATION Shredded Cane Pitch of 38 mm, groove of 35˚ to 55˚ Tooth strength is a concern Small Pitch and Small Angle Breaks easily when hard objects are accidentally milled OTHERS Large Pitch and Large Angle Stronger tooth Higher reabsorption Typically grooved at 38 mm to 56 mm Pressure Feeder Rolls with angles of 35˚ to 45˚ INTERMEDIATE CARRIERS & CHUTES Extraction INTERMEDIATE CARRIERS & CHUTES Extraction Intermediate Carriers Conveyors moving the bagasse from the discharge of one mill to the feed of the next mill Types: Slat or Apron Conveyor and Rake or Drag Type Conveyor INTERMEDIATE CARRIERS & CHUTES Extraction Slat or Apron Conveyor Rake or Drag Type Conveyor Uses slats or plates made of steel, wood, Chains are fitted with angle iron with welded tines that forms the rakes or other materials typically mounted on Drags the bagasse by using rakes roller chains to convey product. The slats Minimal cane spillage are not interlocked or overlapping. Maintenance cost is minimal INTERMEDIATE CARRIERS & CHUTES Extraction Donnelly Chute Vertical chute of sufficient height (not less than 1.5m) positioned to guide the bagasse mat in the feed openings of feeder rolls Extraction MILL DRIVES Typical Drives for Milling: Electric Motors Steam Turbines Hydraulic Motors Steam Engines Extraction MILL DRIVES PARAMETER STEAM TURBINES ELECTRICAL DRIVE HYDRAULIC DRIVE 1. Sensitivity to Environment No Yes No 2. Characteristic Speed Range Very Poor Wide Wide Start/Stop Frequency Poor Limited No Limit Speed Accuracy Limited Very Good Very Good Torque Limitation Poor Good Very Good Ease of Control Difficult Good Good 3. Installation Wiring Negligible Extensive Little Foundation Needed Yes Yes No Alignment Yes Yes No Adaptability to Complex System Difficult Good Good 4. Performance Power to Weight Ratio Very Less 0.35 1.00 Space Requirement Large Area Less than steam turbine Very Less Monitoring of Power Consumption Not Possible By Metering By metering Overall Efficiency 27% 43% 53% 5. Maintenance & Lubrication Heavy Medium Very Less NOTE: This is based on the experience in India. SHREDDED Extraction CANE IMBIBITION WATER BAGASSE TO BOILER MILL 1 MILL 2 MILL 3 MILL 4 MILL 5 TO MUD MIXER FIRST EXPRESSED JUICE (FEJ) JUICE PAN 2 JUICE PAN 3 JUICE PAN 4 JUICE PAN 1 UNSCREENED MIXED JUICE MATERIAL FLOW Extraction IMBIBITION Even when bagasse is subjected to high and Minimum moisture of 45% repeated pressures, it never gives up all the juice which it contains. It approaches a minimum moisture up to 45% in general; BAGASSE BAGASSE that is, it retains a high proportion of juice, amounting roughly to half its weight. IMBIBITION CANE JUICE WATER CANE JUICE In order to extract as much as possible of IMBIBITION WATER the sugar which it retains, since this moisture content cannot be reduced further, the juice has to be replaced with something else. It is called "imbibition“. Extraction IMBIBITION SYSTEM Simple Imbibition Compound Imbibition SHREDDED Extraction CANE IMBIBITION WATER MACERATION WATER MACERATION WATER MACERATION WATER BAGASSE TO MUD MIXER MILL 1 MILL 2 MILL 3 MILL 4 MILL 5 TO BOILER FIRST EXPRESSED JUICE (FEJ) JUICE PAN 2 JUICE PAN 3 JUICE PAN 4 JUICE PAN 1 UNSCREENED MIXED JUICE IMBIBITION VS. MACERATION Extraction IMBIBITION SYSTEM Hot Imbibition (Advantages) Action of temperature in the destruction of the cell walls. The material of the cell walls, which is impermeable, would be softened, and water thus would have direct access to the juice contained in the cells. It provides an excellent use for the hot condensate returned from the last vessels of the multiple effect evaporators Extraction IMBIBITION SYSTEM Hot Imbibition (Disadvantage) WAXES! Most of the waxes melt between 60 and 80°C The optimum imbibition temperature is 80-85˚C At these temperatures, microorganisms present in the juice can be killed. SHREDDED Extraction CANE IMBIBITION WATER MACERATION WATER MACERATION WATER MACERATION WATER BAGASSE TO MUD MIXER MILL 1 MILL 2 MILL 3 MILL 4 MILL 5 TO BOILER FIRST EXPRESSED JUICE (FEJ) JUICE PAN 2 JUICE PAN 3 JUICE PAN 4 JUICE PAN 1 CUSH CUSH UNSCREENED ROTARY MIXED JUICE SCREENED MIXED JUICE SCREEN TANK MIXED JUICE TO RAW HOUSE Extraction Juice Screen Installed above the milling train to facilitate return of bagasse back to the tandem 0.1m2 of metallic cloth/TCH should be provided The screened bagasse is returned to the 2nd mill; it is also known as cush cush Extraction FACTORS AFFECTING EXTRACTION 1. The quality of cane a.) Variety of cane and its quality like trash content and extent of and its preparation deterioration b.) Level of cane preparation 2. The equipment a.) The number of mills in the tandem b.) Mill configuration e.) Feeding devices c.) Mill rolls f.) Trash plate d.) Roll grooving g.) Mill drives 3. The operating a.) Mill settings e.) Juice drainage from the rolls parameter of the mill b.) Hydraulic pressure f.) Extent of imbibition c.) Mill speed g.) Sanitation d.) Condition of roll grooves Extraction CANE DETERIORATION Cane deteriorates rapidly once cut. Knife to knife time should be at most 24hrs. High temperature and sunlight speeds up the drying of stalk and accelerates inversion of sucrose in the cane. In effect, cane not only loses weight but also sucrose. GENERALITIES ON EFFECT OF DELAY IN MILLING HARVESTED CANES Knife to Knife time % loss in % loss in Lkg/TC measured in days cane weight 1 0.5-1.0 0.5-1.0 2 3.5-4.5 3.0-5.0 3 6.0-7.5 11.0-13.0 4 8.5-10.0 15.0-18.0 5 12.0-14.0 20.0-22.0 6 15.0-17.0 25.0-27.0 7 18.0-20.0 29.0-31.0 Canes that are not milled for 24 hours after harvesting can lose 3.5% of its juice purity. After 100 hours, the purity drops by as much as 35%. Source: Sugar cane Milling Manual Vol.1 Extraction CANE DETERIORATION Other causes of and contributory factors in cane deterioration are: Invasion of microorganisms such as dextran-forming bacteria that consume sucrose Inversion of sucrose by enzyme Acid hydrolysis of sucrose Uncontrolled burning of canes Cut cane ends Canes laid down in wet and muddy areas Extraction SUCROSE INVERSION RECALL C12H22O11 C6H12O6 C6H12O6 SUCROSE GLUCOSE FRUCTOSE Extraction POLARIMETRY RECALL Sucrose – dextrorotatory (clockwise) Fructose/Glucose – levorotatory (counterclockwise) Milling CANE DETERIORATION Uncontrolled Burning of Canes Microorganisms rapidly infect badly burnt canes! Burning removes protecting surface wax causing the rind to crack. The split in the rind facilitates entry of bacteria thus increasing the susceptibility of cane to infection. If burn is intense, the juice oozes from damaged stalk and acts as medium for growth of bacteria. Extraction CANE DETERIORATION Post Harvest Deterioration frequently results in polysaccharide formation. SOUR CANES – canes that deteriorate through bacterial action -> Dextran STALE CANES – canes that have been stored without being infected by bacteria -> Sarkaran These may cause delays in processing due to excessively high viscosity and losses due to modification of crystal growth. Extraction CANE DETERIORATION Leuconostoc Mesenteroides - Lactic bacteria - causes souring of cane and converts sucrose to fructose and dextran Extraction CANE DETERIORATION Dextran Glucose polymer Molecular weight ranges from 15,000 – 2,000,000 or higher and is a gummy substance (why it causes high viscosity) Formation is increased by duration of cane storage Inflates polarization reading of sample to artificially high AP as it has the same rotation as sucrose Increases viscosity of the juice, which leads to a decrease in factory capacity Decreases sucrose crystallization rate Formation of needle-shaped sucrose crystals Interference with analyses (false positive AP reading) Poor clarification Greater loss of sucrose to final molasses Extraction CANE DETERIORATION Phaeocytostroma sacchari - An ascomycete fungus which infects sugar cane and produces sarkaran Sarkaran - A polysaccharide that increases viscosity - May cause decreased heat transfer and poor crystallization rates Fungal spores of P. sacchari Source: Boil, P.G. & Wienese, S. & Muir, Barbara. (2006). The cause of sarkaran in sugarcane. International Sugar Journal. 108. 317-326. Extraction FACTORS AFFECTING EXTRACTION 1. The quality of cane a.) Variety of cane and its quality like trash content and extent of and its preparation deterioration b.) Level of cane preparation 2. The equipment a.) The number of mills in the tandem b.) Mill configuration e.) Feeding devices c.) Mill rolls f.) Trash plate d.) Roll grooving g.) Mill drives 3. The operating a.) Mill settings e.) Juice drainage from the rolls parameter of the mill b.) Hydraulic pressure f.) Extent of imbibition c.) Mill speed g.) Sanitation d.) Condition of roll grooves Extraction MILL SANITATION Impact of Poor Mill Sanitation Sucrose losses can go up to 25kg/TC Signs: acidic odor around the mill, presence of slime, abnormal purity drop between FEJ and MJ Extraction MILL SANITATION - WAYS 1. STEAMING 2. BIOCIDE MONITORING AND DETERMINATION OF MILL PERFORMANCE MONITORING AND DETERMINATION OF MILL PERFORMANCE VICLOMAC This system is for sampling First Expressed Juice from individual planter. The control turntable is calibrated such that the travel of the steel ball representing the sample is equivalent to the travel of the actual cane bundle. The crusher lab and the turntable are part of the viclomac system. MONITORING AND DETERMINATION OF MILL PERFORMANCE WET MILLING TEST Reliable guide for mill adjustments as it approximates the true milling condition Juice and Bagasse from the discharge roller of each mill tandem are analyzed for Bx, Pol and AP (Juice) and Pol and Moisture (Bagasse) Extraction of each mill is calculated using Mittal’s Whole Reduced Extraction formula SHREDDED CANE Pol Pol Pol Pol Pol Moisture Moisture Moisture Moisture Moisture MILL 1 MILL 2 MILL 3 MILL 4 MILL 5 Brix Brix Brix Brix Brix Pol Pol Pol Pol Pol AP AP AP AP AP WET MILLING TEST WET MILLING TEST There should be enough canes Speed, capacity and imbibition should be the same as in normal operation No mill trouble (choking, cut off imbibition, etc.) Operating conditions should be noted down (cane variety, steam pressure – live and exhaust, milling rate) Simultaneous taking of juice and bagasse samples OVERALL MASS BALANCE SUGARCANE BAGASSE IMBIBITION WATER MILLS MIXED JUICE 𝑆𝑈𝐺𝐴𝑅𝐶𝐴𝑁𝐸 + 𝐼𝑀𝐵𝐼𝐵𝐼𝑇𝐼𝑂𝑁 𝑊𝐴𝑇𝐸𝑅 = 𝑀𝐼𝑋𝐸𝐷 𝐽𝑈𝐼𝐶𝐸 + 𝐵𝐴𝐺𝐴𝑆𝑆𝐸 EXTRACTION 𝑇𝑜𝑛𝑠 𝑃𝑜𝑙 𝑖𝑛 𝑀𝐽 𝐸𝑥𝑡𝑟𝑎𝑐𝑡𝑖𝑜𝑛 = × 100 𝑇𝑜𝑛𝑠 𝑃𝑜𝑙 𝑖𝑛 𝐶𝑎𝑛𝑒 𝑇𝑜𝑛𝑠 𝑃𝑜𝑙 𝑖𝑛 𝐶𝑎𝑛𝑒 = 𝑇𝑜𝑛𝑠 𝑃𝑜𝑙 𝑖𝑛 𝑀𝐽 + 𝑇𝑜𝑛𝑠 𝑃𝑜𝑙 𝑖𝑛 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 𝑃𝑜𝑙 % 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 𝑇𝑜𝑛𝑠 𝑃𝑜𝑙 𝑖𝑛 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 = × 𝑇𝑜𝑛𝑠 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 100 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 % 𝐶𝑎𝑛𝑒 𝑇𝑜𝑛𝑠 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 = × 𝑇𝑜𝑛𝑠 𝐶𝑎𝑛𝑒 100 𝐹𝑖𝑏𝑒𝑟 % 𝐶𝑎𝑛𝑒 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 % 𝐶𝑎𝑛𝑒 = × 100 𝐹𝑖𝑏𝑒𝑟 % 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 𝐹𝑖𝑏𝑒𝑟 % 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 = 100 − 𝑀𝑜𝑖𝑠𝑡𝑢𝑟𝑒 % 𝐵𝑎𝑔𝑔𝑎𝑠𝑠𝑒 − 𝐵𝑟𝑖𝑥 % 𝐵𝑎𝑔𝑎𝑠𝑠𝑒 REDUCED EXTRACTION 100 − 𝐸 100 − 𝐹 𝐸12.5 = 100 − 7𝐹 Where: E12.5 = Reduced extraction E = % Extraction F = % Fiber in cane This is the extraction of existing condition if the fiber were 12.5%, hence this figure can be used for comparison of work of different mills or of the same mill at different periods. This formula is by Noel Deer. WHOLE REDUCED EXTRACTION 12.5 𝑃𝑏𝑐 𝑊𝑅𝐸𝑀𝑖𝑡𝑡𝑎𝑙 = 100 × (1 − 𝑃𝑐 × 𝐹𝑐 Where: Pbc = Pol in Bagasse%Cane Pc = Pol%Cane Fc = Fiber%Cane