Chapter 1 : Introduction of Oleochemistry(Spheres of environmental chemistry)

By: Miss Noraishah Binti Abdullah

Oleochemistry

• Oleochemicals are chemicals derived from biological oils or fats.

• The hydrolysis or alcoholysis of oils or fats form the basis of the oleochemical industry.

• basic oleochemical substances are:-– fatty acids – fatty acid methyl esters (FAME), – fatty alcohols, – fatty amines and – Glycerols

• Intermediate chemical substances produced from these basic oleochemical substances include

alcohol ethoxylates alcohol ether sulfates

diacylglycerols (DAG), alcohol sulfates

quaternary ammonium substances

monoacylglycerols (MAG),

triacylglycerols (TAG) sugar esters.

Application of oleochemistry

• The most common application of oleochemicals is biodiesel production.

• Another common application is in the production of detergents; lauric acid is used to produce sodium lauryl sulfate, the main ingredient in many personal care products.

• Other applications include the production of lubricants, green solvents, and bioplastics.

Introduction to oleochemical industry in Malaysia• The oleochemical industry in Malaysia started

in the early 1980s. It comprise the basic oleochemicals and oleochemical derivatives sub-sectors. Malaysia is one of the world's leading basic oleochemicals producers and net exporters.

• The oleochemical industry is almost totally dependent on indigenous raw materials, i.e. palm oil and its derivatives and palm kernel oil as feedstocks in the various basic oleochemical products.

• The industry comprises manufacturers of both local and several joint-venture companies with multinationals.

Emergence of palm oil industry

Chapter 2 : Fat SplittingMiss Noraishah Binti Abdullah

2.0 Fat splitting

• Fatty acids are obtained by hydrolysing the fats or what is popularly known of fat splitting process.

• Fat + water Glycerol + Fatty acids

• The mixed fatty acid from fat splitting is separated from glycerine and further purified by pressing or distillation to gets desirable cuts for particular uses.

2.1 Pre-treatment

• Before coming to fat splitting, it will be desirable to consider the various impurities present in the various fatty raw-materials and their purification.

• These impurities should be removed before proceeding with the main process, as they interfere and cause difficulties with the process of fatty acids.

Why we need pre-treatment?

• land animals containing 60±90 per cent fat,

• whole fish with 10±20 per cent oil, • or vegetable seeds and soft plant

tissue with 20±70per cent oil.

In order to get pure products of fatty acids, impurities need to be extracted from fats and oils

Extraction

• Animal fats, from whole animals, depot fats, contain active enzymes, so the fat should be extracted as quickly as possible

• highly unsaturated nature of fish oils also make them liable to rapid oxidation.

• Vegetable fruits, such as those from the oil palm, have a high moisture content and here also the oil should be extracted as quickly as possible to minimise enzymic hydrolysis.

• Pre-treatment process includes:-a) Refiningb) Degummingc) Neutralizationd) Bleaching

a) Refining

• removal of undesirable components and will usually result in a product with minimal colour and flavour

• The compounds removed by refining include phospholipids, free acids, mono- and di-acylglycerols, colour, trace metals, oxidation products and environmental contaminants.

b) Degumming

• Degumming is the treatment of crude oils with water or dilute acid (phosphoric or citric) to remove phospholipids, lecithin, cephalin.

• The popular method- hydrolytic degumming process

• Oil+water- heated with additive such as Ba(OH) or H3PO4 refine and emulsified, removed hydrated gum.

c) Neutralization

This is effected by treatment with alkali

soapstock is separated and can beacidified to give fatty acids.

Soapstock- cheap acidic oil -Soapstock contains free acids

as sodium salts (usually) contaminated with triacylglycerols

and phospholipids.

Traditionally, this has been acidified with sulfuric acid to provide crude fatty acids for soap making or as additives to animal feeds

d) Bleaching

• Bleaching is carried out mainly to reduce colour (carotenes, chlorophyll) and involves heating the oil at 80±180°C (mainly at 90±120°C) in the absence of oxygen with a bleaching earth such as bentonite, fullers' earth, activated carbon, or amorphous silica

• There are at least four known methods of fat splitting:-(1) Twitchell process(2) batch autoclave process(3) continuous process(4) enzymatic process.

(1) Twitchell process• one of the earliest processes developed

for fat splitting low initial• cost and simplicity of installation and

operation-no commercial value

Method.• sulfuric acid to catalyze the hydrolysis.• reagent is a sulfonated mixture of oleic

or other fatty acid and naphthalene

• The operation is carried out in a wooden, lead-lined, or acid-resistant vad

• the fat, water amounting to approximately half the fat, 1–2% sulfuric acid, and

• 0.75–1.25% Twitchell reagent are boiled at atmospheric pressure for 36–48 h, using open steam.

• The process is usually repeated two to four times, drawing off the glycerine–water solution after each stage.

• At the last stage, water is added and the mixture boiled to wash off any remaining acid.

• The long reaction period, high-steam consumption, and discoloration of the fatty acids are disadvantages of the process and are the reasons for its limited use today.

(2) batch autoclave process

• The batch autoclave process is the oldest commercial method used for splitting higher grade stock to produce light-colored fatty acids.

• more rapid than the Twitchell process, taking about 6–10 h to complete.

Method

• process uses a catalyst, usually zinc, magnesium,or calcium oxides.-zinc is the most active.

• 2–4% catalyst is used, and a small amount of zinc dust is added to improve the color of the fatty acids.

• The autoclaves are tall cylinders, 1220–1829 mm in diameter and 6–12 m high made of corrosion-resistant alloy and fully insulated. An injection of live steam provides the agitation, although some, in addition, use mechanical agitators.

• In operation, the autoclave is charged with the fat, water amounting to about half the fat, and the catalyst.

• Steam is blown through to displace any dissolved air, and the autoclave is closed.

• Steam is admitted to raise the pressure to 1135 kPa and is injected continuously at the bottom while venting a small amount to maintain the desired agitation and operating pressure.

• More than 95% conversion is achieved after 6–10 hour.

• The contents of the autoclave are transferred to a settling tank

• two layers are formed: the fatty acid upper layer and the glycerine (sweetwater) lower layer. The fatty acid layer is drawn off, treated with mineral acid to split the soap formed, and finally washed to remove traces of the mineral acid.

(3) continuous process• The continuous countercurrent, high-

pressure fat-splitting process, knownly as the Colgate–Emery process.

• The high temperature and pressure used permit short reaction time.

• Full countercurrent flow of oil and water produces a high degree of splitting without the need of a catalyst. However, a catalyst may be used to increase reaction rate.

• The splitting tower is the heart of the process.

• Most splitting towers have the same configuration and basically operate the same way.

• Depending on the capacity,the tower can be 508–1220 mm in diameter and 18–25 m high and is made of corrosion-resistant material such as stainless steel 316 or Inconel alloy

• designed to operate at a pressure of about 5000 kPa.

• The deaerator fat is introduced by means of a sparge ring, around 1 m from the bottom with a high-pressure pump.

• Water is introduced near the top at a ratio of 40–50% of the weight of the fat.

• The high splitting temperature (250–260°C) ensures adequate dissolution of the water phase into the fat

• so that mechanical means for bringing thetwo phases into contact are not required.

• The empty volume of the tower is used as the reaction compartment.

• The crude fat passes as a coherent phase from the bottom to the top through the tower,

• whereas the heavier splitting water travels downward as a dispersed phase through the mixture of fat and fatty acid.

• Degrees of splitting up to 99% can be reached• reaction time of only 2–3 h. • Little discoloration of the fatty acids occur. • Reaction produce efficient internal heat

exchange, this process affords high steam economy.

• The utilities consumption per ton of feed is as follows.

• Steam (6000 kPa) 190 kg• Cooling water (20°C) 3 m3

• Electrical energy 10 kWh• Process water 0.6 m3

Method.

(4) enzymatic process.• Fat splitting through the use of lipolytic

enzymes had been carried out in experimental trials. However, at present, this process is of doubtful importance because of its high cost and long reaction time.

• The enzymatic splitting of fats and oils by lipase from Candida Rugosa, Aspergillus niger, and Rhizopus arrhizus had been studied at a temperature range of 26–46C for a period of 48–72 h.

• About 98% splitting is possible

Purification and fractionation of FA

• The FAs obtained by the fat-splitting unit are in a crude state and require purification, which is accomplish by distillation.

• The boiling points of most of the fatty acids are above 300°C and most of the unsaturated fatty acids decompose at this temperature.

• In order to purify them without decomposition, distillation should be carried out at lowest possible temperature and hence at the lowest possible pressure.

Fatty Acid Distillation and Fractionation Operations

• Fatty Acid Distillation. Distillation of crude fatty acids removes both the low and high boiling impurities as well as odor bodies.

• Fatty acids are extremely sensitive to heat, oxidation, and corrosion effects-due to the reactive acid group at the end of the long carbon chain.

• These factors are taken into consideration in thedesign of the distillation unit and its operating parameters.

Distillation is carried out under high vacuum and lower temperatures and shorter time.

• Technical design of most distillation units features high vacuum

• NO Allowance for air leakage, effective heating to achieve short contact time, good circulation for effective mass transfer between vapor and condensate, and steam economy.

• Crude fatty acid is predried and degassed under vacuum and fed to the distillation unit, which is operated at a vacuum of 1.2 kPa or less and a temperature of approximately 200°C.

Fatty Acid Fractionation.• developments in fractionation technology

can now readily meet this challenge. Purities of 99.5% can be achieved for pure cuts of C12 or C14 fraction.

• The detergent-grade feedstock C12–C18 fraction is separated from the whole cut by

topping off the C8–C10 fraction. • middle cut, C12–C14, can be further

fractionated from the C12–C18 cut through the use of multistage fractionation employing two or more columns.

• Basically, each process uses a deaerator, heat source, fractionation column, condensing system, and vacuum source