OIL AND FAT OIL AND FAT TECHNOLOGY TECHNOLOGY

LECTURES LECTURES IV IV

(Refined Oil Production)(Refined Oil Production) Prof.Dr.Aytaç SAYGIN GÜMÜŞKESENProf.Dr.Aytaç SAYGIN GÜMÜŞKESEN

Yrd.Doç.Dr.Fahri YEMİŞÇİOĞLUYrd.Doç.Dr.Fahri YEMİŞÇİOĞLU

Refining of crude oilRefining of crude oilCrude oils as received from the extraction

plant contain several non-triglyceride components which must be removed.

Refining consists of several processes which accomplish this aim.

A refining process is carried out following extraction of A refining process is carried out following extraction of crude edible oils by means of screw presses and/or crude edible oils by means of screw presses and/or solvent extraction. solvent extraction.

In refining, physical and chemical processes are In refining, physical and chemical processes are combined to remove undesirable natural as well as combined to remove undesirable natural as well as environmental-related components from the crude oil. environmental-related components from the crude oil.

These components comprise for example These components comprise for example phosphatides, free fatty acids, pigments (such as phosphatides, free fatty acids, pigments (such as chlorophyll), odors and flavors (including aliphatic chlorophyll), odors and flavors (including aliphatic aldehyde and ketone), waxes as well as heavy metals, aldehyde and ketone), waxes as well as heavy metals, pesticides etc. pesticides etc.

Depending on the requirements, the following basic processes are implemented:

degumming for removal of phosphatides, degumming for removal of phosphatides, neutralization for removal of free fatty acids, neutralization for removal of free fatty acids, bleaching for removal of color, bleaching for removal of color, deodorization to distill odors and flavors as deodorization to distill odors and flavors as

well as free fatty acids and well as free fatty acids and winterization for separation of waxes. winterization for separation of waxes.

Refining MethodsRefining MethodsChemical Refining DegummingDegumming NeutralizingNeutralizing BleachingBleaching DeodorizationDeodorizationPhysical RefiningPhysical Refining DegummingDegumming BleachingBleaching Steam distillationSteam distillation

DegummingDegummingThe aim of degumming operation;The aim of degumming operation; The emulsifying action of phospholipids The emulsifying action of phospholipids

increases oil losses during alkali refining.increases oil losses during alkali refining. Gums lead brown discoloration of oil after Gums lead brown discoloration of oil after

heating during deodorization.heating during deodorization. Salts may be formed with cooper, Salts may be formed with cooper,

magnesium,calcium and iron, accelerating magnesium,calcium and iron, accelerating oxidative degredation of oil.oxidative degredation of oil.

Certain phospholipids, such as lecithin, find Certain phospholipids, such as lecithin, find widespread industrial application.widespread industrial application.

Gums•Two main types –Hydratable Phosphatides-easy to remove –Non-Hydratable Phosphatides(NHP) -hard to

remove from oil •some NHP removed with hydratables in water degumming •requires the use of a acid to convert to hydratable for complete removal

Model of phospholipidsModel of phospholipids

Phosphatidic cholin P.inositol P.ethanolamin P.acid

The groups on the phosphor differ in size and sturcture. The larger the group the more hydratable is the phospholipids

Hydrolysis of phospholipidsHydrolysis of phospholipids

oil oil

water water

PCPA

hydrolysis

When phospholipids is hydrolyzed to lyso-form they become hydratable.

PC

PA

Objectives of Refining 1. Removal of undesired products from crude oils •free fatty acids (FFA) •phospholipids (gums) •oxidised products •metal ions •colour pigments •other impurities 2.Preservation of valuable vitamínes. (vitamina E ortocopherol–natural anti-oxidants) 3.Minimize oil losses 4.Protection of the oil against degradation

Different degumming processes are carried out Different degumming processes are carried out to remove phosphatides. For efficient and to remove phosphatides. For efficient and economic application of this procedure economic application of this procedure appropriate machines and equipments are appropriate machines and equipments are used.used.

1.1. Water degummingWater degumming2.2. Acid degumming Acid degumming 3.3. Enzymatic degummingEnzymatic degumming4.4. Membrane degummingMembrane degumming

Water degumming A large part of the phosphatides (gums) can be A large part of the phosphatides (gums) can be

hydrated quickly and easily. If the pressed or hydrated quickly and easily. If the pressed or extracted oil contains a considerable quantity of extracted oil contains a considerable quantity of gums the oil is subjected to the water degumming gums the oil is subjected to the water degumming process immediately following extraction. In this process immediately following extraction. In this process, water is added to the oil. After a certain process, water is added to the oil. After a certain reaction period the hydrated phosphatides can be reaction period the hydrated phosphatides can be separated either by decantation (settling) or separated either by decantation (settling) or continuously by means of centrifuges. continuously by means of centrifuges.

In this process step a large part of hydratable and In this process step a large part of hydratable and even a small proportion of the non-hydratable even a small proportion of the non-hydratable phophatides are removed. The extracted gums can phophatides are removed. The extracted gums can be processed into lecithin for food, feed or for be processed into lecithin for food, feed or for technical purposes. technical purposes.

Water Degumming Process Steps

• Heat oil to 60 -70 °C• Water addition and mixing• Hydration mixing 30 minutes• Centrifugal separation of hydrated gums• Vacuum drying of degummed oil• Gums -dried for edible lecithin or

recombined in meal

water

heatersteam

reactor

seperator

mixer

gums

vacuum

Vacuum dryer

to storage

Water DegummingPhosphorous in degummed oil -50 to 200 ppm max

Moisture in dried and degummed oil -< 0.1%.

Acid degummingAcid degummingDry acid degumming:Dry acid degumming: Dry acid degumming is particularly suit- Dry acid degumming is particularly suit-

able for processing oils with low gum contents such as palm able for processing oils with low gum contents such as palm oil, coconut oil, palm kernel oil or animal fats. Intensive mixing oil, coconut oil, palm kernel oil or animal fats. Intensive mixing is implemented following addition of acid to the pre-heated is implemented following addition of acid to the pre-heated crude oil. The conditioned gums are absorbed into the crude oil. The conditioned gums are absorbed into the bleaching earth and are separated by filtration. bleaching earth and are separated by filtration. The benefits of the dry acid degumming process are:The benefits of the dry acid degumming process are:

Efficiency as a result of Efficiency as a result of low energy consumption, low energy consumption, low operation and maintenance costs (sturdy and reliable control low operation and maintenance costs (sturdy and reliable control

system),system), long service life (the components are acid proof), long service life (the components are acid proof), low investment costs, low investment costs, environmental-friendly as no wastewater or soap stock occur. environmental-friendly as no wastewater or soap stock occur.

Wet acid degumming :Initially oils with higher gum :Initially oils with higher gum contents (e.g. corn oil) are similarly processed as in contents (e.g. corn oil) are similarly processed as in dry acid degumming. However, to achieve gum dry acid degumming. However, to achieve gum hydration water is added following acid apportioning. hydration water is added following acid apportioning. The gums are removed by a separator prior to The gums are removed by a separator prior to bleaching. This process is beneficial asbleaching. This process is beneficial as

centrifuges enable easy separation of gums in oil centrifuges enable easy separation of gums in oil types with higher non-hydratable gums contents (e.g. types with higher non-hydratable gums contents (e.g. rape oil and soybean oil), rape oil and soybean oil),

the consumption of bleaching earth is reduced the consumption of bleaching earth is reduced because the oil has already been extensively because the oil has already been extensively degummed. degummed.

Dry or wet acid degumming are not always sufficient to Dry or wet acid degumming are not always sufficient to reduce gums to the value required in the oil prior to reduce gums to the value required in the oil prior to the combined deodorization and distillation process. the combined deodorization and distillation process. Thus, a special degumming process is developed.Thus, a special degumming process is developed.

Acid Degumming Process Steps

• Heat oil to 60 -70 °C• Acid addition and mixing• Hydration mixing 30 minutes• Centrifugal separation of hydrated gums• Vacuum drying of degummedoil• Gums -recombined in meal

Acid Degumming

Crude oil heater acid

mixer

water

reactor

mixer To drying / storage

gums

Phosphorous in degummed oil -20 to 50 ppmmax.Moisture in dried and degummed oil -< 0.1%

Alfa Laval Special Degumming

•Heat oil to 60 oC•0.05-0.2 % Phosphoric Acid with intensive mixing•Partially neutralise with dilute lye (hydration water)•Gentle mixing and holding for 60 minutes•Gums centrifugation•Optional water wash step for lower phosphorous •Oil drying

Alfa Laval Special DegummingPhosphorous in oil -20 to 30 ppmmax.

Phosphorous in oil -8 to 10 ppmmax. with washingMoisture in dried oil -< 0.1%

crude oil heater

reactor

mixer mixer

acid

lye

waterOil temperature trimmer seperator

steam

cooling water

Degummed oil

Gums

Enzymatic degummingEnzymatic degumming was first introduced by the German

Lurgi Company as the »Enzy Max process« .The EnzyMax process can be divided into four different steps:

(i) the adjustment of the optimal conditions for the enzyme reaction, i.e. optimal pH with a citrate buffer and the optimal temperature; (ii) the addition of the enzyme solution; (iii) the enzyme reaction; (iv) the separation of lysophosphatide from the oil at about 75 °C.

Enzymes for enzymatic degumming; Lecitase® 10L (pancreatic phospholipase A2) Lecitase® Novo (microbial lipase) Lecitase® Ultra (microbial lipase)

The enzyme solution (Aqueous solution of

citric acid, caustic soda and enzymes) is dispersed into filtered oil at mild temperature, a high speed rotating mixer used for effective mixing of enzyme and oil. The conversion of non-hydratable phospholipids (NHPs) into hydratable phospholipase (HPs) is attained by the effect of enzyme, the enzyme treated oil is sent to mechanical separation and the degummed oil received is dried under vacuum and suitable for further process.

Enzymatic degumming

Enzymatic degummingEnzymatic degumminghttp://www.novozymes.com/NR/rdonlyres/66481D20-BE7E-4C12-ADD2-http://www.novozymes.com/NR/rdonlyres/66481D20-BE7E-4C12-ADD2-

DC2C3E4D53CD/0/degumming.swfDC2C3E4D53CD/0/degumming.swf

NEUTRALISATION Objective:Removal of free fatty acids Two different refining principles: 1.Chemical Refining:Removal by a

chemical reaction with alkali(caustic soda)

2. Physical Refining:Removal by distillation at higher temperature and low vacuum

Batch Neutralization:Batch Neutralization: Refining of vegetable oils is essential to ensure Refining of vegetable oils is essential to ensure

removal of gums, waxes, phosphatides and removal of gums, waxes, phosphatides and free fatty acid (F. F.A.) from the oil; to impart free fatty acid (F. F.A.) from the oil; to impart uniform colour by removal of colouring uniform colour by removal of colouring pigments and to get rid of unpleasant smell pigments and to get rid of unpleasant smell from the oil by removal of odiferous matter.from the oil by removal of odiferous matter.

Refining is carried out either on batch Refining is carried out either on batch operation or as continuous operation. With operation or as continuous operation. With certain oils even physical refining can be certain oils even physical refining can be carried out instead of chemical. carried out instead of chemical.

For processing less than thirty tones of For processing less than thirty tones of oil per 24 hours, and when oil has oil per 24 hours, and when oil has F.F .A. content of 1 % or less normally F.F .A. content of 1 % or less normally batch process is recommended. Batch batch process is recommended. Batch process involves low capital process involves low capital investment, simplicity of operation and investment, simplicity of operation and low maintenance, making refining low maintenance, making refining economically a viable proposition even economically a viable proposition even at capacity as low as 10 tonnes per 24 at capacity as low as 10 tonnes per 24 hours.hours.