Organic Industrial Chemical Industries Part I

• Organic Industrial Chemical Industries Part I covers:
  • Petroleum Processing
  • Synthetic Polymers

Petroleum Processing Introduction

• "Petroleum" comes from the Latin stems meaning "rock" and "oil".
• Petroleum describes gases, liquids, or solids made of hydrocarbons beneath the Earth's surface.

Common Forms of Petroleum

• Natural gas is a mixture of hydrocarbons accumulating in porous rocks.
• Contents of natural gas include methane (80%), ethane (7%), propane (6%), butane and isobutane (4%), and pentane (3%).
• Most hydrocarbons are extracted before natural gas is sold.
• Commercial natural gas is a mixture of mostly methane.
• Liquefied petroleum gas is natural gas liquefied under pressure.
• Crude oil is a composite that occurs naturally, accounting for 50-95% by weight.
• Distillation is the process used to separate crude oil into different hydrocarbon fractions.
• Non-fuel applications include use as petroleum solvent, greases and waxes, or as raw materials for petrochemical synthesis.

Oil Extraction

• Petroleum is found in oilfields or reservoirs beneath the Earth's surface.
• Oil can sometimes be in underground reservoirs and flow to the surface on its own.
• CO2, H2O, and natural gas or steam may be used to induce well pressure to pump oils on the surface.

Evolution of Petroleum Refining

• Petroleum refining evolved to meet consumer demands for better and different products.
• Development of the internal combustion engine led to increased petroleum production.
• The invention of airplanes and jets created an initial need for cleaner burning fuels.

Refining History

• 1862: Atmospheric distillation produced kerosene and naphtha/tar as by-products.
• 1870: Vacuum distillation originally produced lubricants, then cracking feedstocks in the 1930s, asphalt/residual, and coker feedstocks.
• 1913: Thermal cracking increased gasoline yield by producing residual bunker fuel.
• 1916: Sweetening reduced sulphur and odors.
• 1930: Thermal reforming improved the octane number to get residual.
• 1932: Hydrogenation removed sulfur and created gasoline basestock, sulfur, and coke.
• 1933: Solvent extraction improved lubricant viscosity index to form aromatics.
• 1935: Solvent dewaxing improved pour point to form waxes.
• 1935: Catalytic Polymerization improved gasoline yield and octane numbers, forms petrochemical feedstocks.
• 1937: Catalytic cracking improved octane numbers, forms petrochemical feedstocks.
• 1939: Visbreaking reduced viscosity to produce increased distillate and tar.
• 1940: Alkylation increased gasoline octane number to yield high-octane aviation gasoline.
• 1940: Isomerization created alkylation feedstock to form naphtha.
• 1942: Fluid catalytic cracking increased gasoline yield/octane and produced petrochemical feedstocks.
• 1950: Deasphalting increased cracking feedstock for asphalt. – 1952: Catalytic reforming converts low-quality naphtha into aromatics.
• 1954: Hydrodesulfurization removed sulphur.
• 1956: Inhibitor sweetening removed mercaptan to form disulfides

Continued Refining History

• 1957: Catalytic Isomerization converts molecules for better octane number to form alkylation feedstocks.
• 1960: Hydrocracking improves quality and reduces sulphur to form alkylation feedstocks.
• 1974: Catalytic Dewaxing improves pour point to create Wax.
• 1975: Residual Hydrocracking increases gasoline yield from residual to heavy residuals.

Characteristics of Crude Oil

• Crude oil ranges in color and consistency from water-like to tar-like.
• 84% of crude oil composition is carbon.
• 14% of crude oil composition is hydrogen.
• 1-3% of crude oil composition is sulphur.
• Less than 1% of crude oil composition is N, O, metals, and salts.

Hydrocarbons in Crude Oil

• Paraffins are hydrocarbon compounds found in crude oil with formula CnH2n+2.
  • Paraffins can be straight chain or branched (isomers).
  • Paraffin molecules are found in gases and paraffin waxes.
  • Paraffins can be found in the fraction of crude oil and highly affect octane.
• Aromatics include simple compounds such as benzene and naphthalene, as well as complex aromatics.
  • Aromatics have high anti-knock value and good storage stability.
• Naphthenes are saturated hydrocarbon groupings and arranged in a cyclic form.
  • Found in all fractions of crude oil, except for the lightest naphtha.
  • Contain five to six carbons such as cyclohexane.
  • Double-ringed naphthene is found in heavier ends of naphtha.
• Alkenes are commonly formed by cracking.
  • Alkenes don't naturally occur in unprocessed crude oil.
  • Examples of alkenes include ethylene, butene, and isobutene.
• Dienes and Alkynes are obtained in processing of crude oil through cracking.
  • 1,2-butadiene and 1,3-butadiene are examples of dienes (diolefins).
  • Acetylene is a typical alkyne.

Non-Hydrocarbons in Crude Oil

• Sulfur compounds such as H2S, mercaptans, sulfides, disulfides, thiophenes, and elemental sulfur may be present.
  • H2S corrodes refinery units.
  • Combustion of petroleum containing sulphur leads to undesirable by products.
  • Processes are done to remove sulfur during refinery processing steps.
• Oxygen compounds include phenols, ketones, and carboxylic acids.
• Nitrogen compounds are found in crude oil.
  • The products of the decomposition of nitrogen compounds during catalytic cracking in crude oil include nitrogen.
  • NH3 and CN- can cause corrosion.
• Trace metals such as V, Ni, and Fe are found in crude oil.
  • Traces of metals are removed during refining.
• Salts includes NaCl, MgCl2, and CaCl2 in suspension or dissolved in water/brine that form emulsion.
  • Salts are removed by mechanical or electrical desalting
  • Hydrolysis of metal chlorides may result in the production of HCl, which can react with ammonia and thus cause corrosion.
• CO2 may result from the decomposition of molecules or is added to crude oil or from steam used during distillation.

Petroleum Refining Processes

• The petroleum industry began by drilling the first commercial oil well in 1859.
• Petroleum refinery products include gasoline, kerosene, propane, fuel oils, lubricating oil, wax, and asphalt.
• 2 kinds of processes are involved in petroleum refining:
  • Physical processes refine crude oil without altering its molecular structure. Process of separating crude oil in atmospheric and vacuum distillation towers of hydrocarbon compounds, “fractions” or “cuts”.
  • Chemical conversions alter the hydrocarbon molecules to produce products. includes thermal and catalytic cracking, alkylation, isomerization, catalytic reforming, polymerization.
• Treatment processes prepare HCs streams for additional processing and to prepare finished products such as dissolving, absorption and precipitation.
• These processes are performed in combination with hydrodesulfurization and sweetening.
• Formulation and blending is mixing and combining hydrocarbon fractions, additives, to produce finished product.

Cracking and Reforming

• About 10% of the product of distillation of crude oil is straight-run gasoline.
• Modern cars run at a compression ratio of 9:1.
• Because straight-run gasoline burns unevenly in high compression engines, they often lead to shock wave and engine knocking.
• Branched alkanes and cycloalkanes burn more evenly than straight-run gasoline.
• Short alkane (C4H10) burns more evenly than C7H16.
• Alkenes burn more evenly than alkanes.
• Aromatic HCs burn more evenly than cycloalkanes.

Octane Numbers

• Octane Numbers measure the ability of a gasoline type to burn without knocking.
• Octane number compares a gasoline's tendency to knock against the tendency to knock of a blend of heptane and isooctane.
• Isooctane is more resistant to knocking, its rating is compared to heptane.
• 87% isooctane and 13% heptane has an octane number of 87.

How to Increase Octane Numbers

• Thermal Reforming is carried out at high temperature (500-600°C) and high pressure (25-50 atm).
  • Straight-chain alkanes isomerize to form branched alkanes and cycloalkanes that increases the octane number.
• Catalytic Reforming is carried in the same conditions as thermal reforming:
  • Catalyst used for catalytic reforming includes silica (SiO2) and alumina (Al2O3).

Catalytic Reforming

• Catalytic reforming is used to convert low-octane naphthas into high-octane gasoline.
  • Blending components called "reformates".
• Reformates have very high concentrations of toluene, benzene, xylene, and other aromatics useful in gasoline blending and petrochemical processing.
• Platinum is often used as the active catalyst.

Catalytic Cracking

• Catalytic cracking uses catalysts to break long-chain HCs into smaller fragments for gasoline.
• Cracking long-chain HCs leads to increased gasoline yield.
• Catalytic cracking increases the quality and quantity of lighter products and decrease number of residuals.
• The most important organic chemical feedstocks are Ethylene and Propylene, accounting for over 50-60% of all organic chemicals.
• These olefins (alkenes) are high reactive, and few can be found in natural gas or crude oil.
• Must be made in a cracking process.
• Decomposition of heavy HCs take place by catalytic action or heating.
• Catalysts commonly used in refinery cracking are Zeolite, Aluminum hydrosilicate, Treated bentonite clay, Bauxite, and Alumina-silicate.
• Key functions for Catalytic Cracking:
  • Reaction: feedstock reacts with catalyst and cracks into different hydrocarbons
  • Regeneration: catalyst is reactivated by burning off coke
  • Fractionation: cracked HC stream is separated into various products

Additional Refining Processes

• Polymerization joins up low molecular masses to form high molecular weight components.
• Propylene and iso-butylene are common olefins polymerized in the vapor phase reaction.
• Alkylation combines an olefin with aromatic HC.
• Process used for converting gaseous HCs to gasoline in the presence of HF or H2SO4.

Synthetic Polymers: Introduction

• The industrial use of polymers started when Goodyear discovered the vulcanization of rubber in 1839.
• Polymer research led to the development of many synthetic polymer such as nylon, polyethylene, and polyvinyl chloride.
• The word “Polymer” came from two Greek words: "polys" meaning "many", and "meros" meaning "parts".
• Polymers are high molecular mass compounds of hundreds or thousands of identical basic units (monomers).

Classifications of Polymers

• Linear polymers have repeating units like the links in a very long chain (e.g., polyethylene).
• Branched polymers have some molecules attached to the linear chain as side chains.
• Three-dimensional cross-linked polymers contain branched chains joined together by cross-linking called "curing".
  • Vulcanization of rubber is an example of curing.

Polymer Properties

• Molecular weight (MW) of polymers is not fixed, but varies with chain length.
• Varying MW and chain length of polymers influences crystallinity.
  • Most polymers are amorphous and only-semicrystalline.
• Glass Transition temperature refers to the temperature when polymers lose their rigid state.
  • At glass transition temperature, polymers soften, become more elastomeric, and do not melt

Types of Polymer

• Plastics contain an essential ingredient.
  • These are usually amorphous or crystalline polymers that are hard and brittle at ordinary temperatures.
• Thermoplastics soften and mold on heating.
  • Elastic and flexible above a certain glass transition temperature
  • Nylon was the first commercial polymer, used as a substitute for silk
  • Special grades of Nylon 6-6 and Nylon 6 are available
• Thermosetting Plastics involve considerable crosslinking, so manufactured product cannot melt or be dissolved.
  • Materials are made rigid through curing, the addition of sulphur.
  • Curing yields a cross-linked polymer that creates a 3D rigid structure that makes thermosets suitable for high temperature applications up to the decomposition temperature of these materials.
  • Examples include products made of vulcanized rubber, polyester resin, epoxy resin, and bakelite.
• Elastomers
  • Materials that can return to original shape when a force or stress is removed
  • Are amorphous polymers with considerable cross-linkage.
  • Elastomers are mainly thermosets that require vulcanization, although some are thermoplastic.
  • Examples include Silicone rubber, Nitrile rubber, Styrene-butadiene, Polyurethane rubber, Tetrafluoropropylene, and Tetrafluoroethylene.
• Adhesives are alternatives to traditional glue that contains animal products.
  • Polyvinyl acetate, PVA, or Epoxide resin are the common components of adhesives or sealants.
• Synthetic fibers include cellulose acetate, nylon, acrylic and polyester.
  • Natural fibers include wool or silk, vegetable fibers (cotton).
• Surface finishes can replace naturally "dying" oils such as linseed.
  • These polymer products are made as water-based polymer emulsion.

Uses of Thermoplastic Materials

• Low-density polyethylene (LDPE) is used in: packaging films, wire and cable insulation, toys, flexible bottles, houseware.
• High-density polyethylene (HDPE) is used in: bottles, drums, pipes, films, sheets, wire and cable insulation.
• Polypropylene PP is used in: automobile and appliances parts, furniture, cordage, carpets, film packaging.
• Polyvinyl chloride PVC is used in: Construction, rigid pipes, flooring, wire and cable insulation, film and sheet.
• Polystyrene is used in: Packaging (foam and film), foam, insulation, appliances, houseware.

Thermoset Material Uses

• Phenol-formaldehyde (PF) is used for: electrical and electronic equipment, automobile parts, utensils, handles, plywood adhesives, particle board binder.
• Urea-formaldehyde (UF) is similar to PF in textile treatments.
• Unsaturated polyester (UP) is used for: construction, automobile parts, marine accessories.
• Epoxy is used for: protective coating, adhesives, electrical/electronics, material composites in industrial flooring.
• Melamine-formaldehyde (MF) is similar to UF, used in: decorative panels, counter and table tops, dinnerware.

Polyethylene Industry Introduction

• Ethylene monomer of polyethylene is derived from either of two methods:
  • Modification of natural gas (CH4, C2H6, C3H8 mix).
  • Catalytic cracking of crude oil.
• Commercial PE monomers range from 1,000–10,000, with a MW ranging from 28,000–280,000.

Manufacturing of PE

• Categorized under into "high-pressure” or “low-pressure” methods by product type:
  • High-density PE (HDPE)
  • Low-density PE (LDPE)
  • Linear low-density PE (LLDPE)
• High pressures yields low-density PE (LDPE) Low Pressure, created first PE with Aluminum at 10-80bar, and temperatures around 70 °C to 300 °C
• PE produced is stiffer with better density and high-density PE (HDPE).
• DuPont Canada made in the 1950's Linear low-density PE (LLDPE)
• Fluidized bed reactors are commonly used in the PE manufacturing industry.
  • C2H4 gas is pumped from the bottom of the reactor.
  • This gas is compressed and heated prior to entering the reactor bed.
  • The fluidized bed contains a metallic catalyst that is "fluidized" by the flow of ethylene gas.
  • Pressure ranges 100 300 psi, with temperatures around 100°C.
  • Unreacted ethylene gas is recycled back into the reactor.