Chemical Refining of Oils in Solvent Phase - Results Directaocs.files.cms-plus.com/Meetings/ChinaPresentation/Zeldenrust... · Top Degumming Crude oil. Condensate. Steam. M . Acid

GEA Mechanical Equipment

Fundamentals of Oilseed and Edible Oil Processing and Refining Short Course, Shanghai, 2014 Robert Zeldenrust

Chemical Refining of Oils in Solvent Phase


• Miscella Refining • Chemical neutralisation of edible fats and oils in the miscella phase

• Alcohol Neutralisation

• Chemical neutralisation of fats and oils with the alkaline glycerin / alcohol phase from a transesterification process as pre-treatment in biodiesel plants

• Safety issues

• Requirements for the use of equipment for explosive products

Overview

Renewable Resources - Chemical Refining of oils in solvent phase 2





• Safety issues


Overview



Integration of Miscella Refining into the extraction plant

Extraction

Miscella Refining

Stripping stage

2nd hexane evaporation stage

Degummed and neutralised oil

1st hexane evaporation stage

Soapstock

Press oil

Toaster Pressing/Flaking

Steam

Hexane Seed Meal

Soapstock Desolventizer

15-20% Oil content

60-70% Oil content



• Separators can handle liquid mixtures of a certain specific gravity difference • The specific gravity difference of the unconcentrated miscella after the

extractor and the soapstock is too large • The specific gravity difference of the miscella after the 2nd hexane

evaporation stage and the soapstock is too small – no advantage to standard alkaline neutralisation

• The flowrate of pre-concentrated miscella is lower

• The miscella concentration can be adjusted by the first hexane evaporator or by adding press oil to the crude miscella

Why is the miscella refining done after the first hexane evaporation?



Density meter

Miscella Refining

Miscella from Extractor Press Oil

Hexane

Optional: Miscella mixing



Miscella Refining – Standard process

• Process conditions: • Miscella concentration: min. 60 %, max. 70% • Process temperature: 50 - 55 °C • Caustic soda concentr.: 14 – 20 % • Caustic soda excess: 10 - 40 % • Retention time: 10 - 12 min.

M caustic soda steam

condensate

N2

N2

N2

refined miscella

operating water

crude

miscella

soapstock



• Only a 1-stage refining process necessary • Low soap content in the neutralised oil (<100 ppm) without washing • No waste water • Higher yield compared to conventional alkali refining • Optimal gossypol removal in case of cottonseed oil • Less fouling of the hexane evaporators • Only bleaching and deodorisation after extraction

Advantages of Miscella Refining



• Soapstock Desolventizer before splitting (if the soapstock cannot be added into the desolventizer/toaster)

• Higher fat content of the meal • Grey color of the meal (instead of white) • Adopted design of the desolventizer / toaster and the hexane

distillation columns • Special design centrifuges for safety reasons

Disadvantages of Miscella Refining





• Chemical neutralisation of fats and oils with the alkaline glycerin/alcohol phase from a transesterification process as pre-treatment in biodiesel plants

• Safety issues


Overview



• Easy integration in biodiesel process

• Use of the alkaline of the glycerin phase after the first transesterification stage

• Alcohol (Methanol) for breaking emulsions and higher selectivity

• Glycerin for getting has a higher density difference to the oil phase – better separation and higher selectivity

• Glycerin is hygroscopic - drying of the oil

• Very good oil quality (low Phosphor content)

Reasons for alcohol neutralisation



Integration of pre-degumming and alcohol refining in the transesterification process

Degumming

Trans- esterification

Soap Splitting

Heavy Phase

Glycerol- processing

Alcohol Neutralisation

Methylester

glycerol phase from 1st reaction of transesterification

heavy phase from alc. neutralisation

FFA

Crude oil

Gums



Pre-treatment: TOP Degumming/ Alcohol Neutralization

Top Degumming

Crude oil

Condensate

Steam

M

Acid

M

Lye Water

Separator Clarifier

Sludge

Holding tank

Glycerin / Alkohol/Alkali Glycerine / Alcohol /Alkaline

Glycerine / Methanol / Water/Soap / Gums

Neutral Oil Methanol

Lauge Lye

Methanol M

M

Alcohol Neutralisation: Westfalia Patent

Top Degumming plus Alcohol Neutralisation ensures perfect glycerine quality



• Less investment costs compared with physical refining and combination of alkaline refining plus soap splitting

• No high contaminated waste water • No water wash • No acid water from soapstock splitting

• Higher yield

• Less steam consumption

• Same temperature in Pre-treatment and transesterification ( 60°C) • No high pressure steam necessary

(no physical refining and vacuum drying)

Alcohol Neutralization in combination with a pre-degumming



• No bleaching earth/ absorbent use • No caustic soda necessary up to 1.5 % FFA content of the crude oil • Full recovery of the FFA of the degummed oil in the soap splitting of

the glycerin treatment section • High availability, even in case of dirty oils, whole system can be CIP

(Cleaning in Place) • High glycerin quality, Phosphatides are reduced in the pre-

degumming stage.

Alcohol Neutralization in combination with a pre-degumming






• Safety issues in case of solvents


Overview



Explosion Triangle

Burning Substance

Explosive

Oxidator - Air atmosphere Burning Substance - Explosive gas dust Ignition Source - Equipment



Ignition Sources of Centrifuges

hot surface • gas friction of the fast rotating bowl • un-balance of the bowl • damaged bearings or gaskets • damaged V-belts

mechanically induced sparks • un-balance of the bowl • heavily damaged bearings • no proper adjusted or any broken parts

electrostatic loading • high flow rates in small gabs • spraying mist (aerosol) • damaged belts or rubbing gaskets



Avoid Explosive Atmosphere

Explosive safe

operation

Burning Substance Non-Explosive Atmosphere

change process conditions

Burning Substance

Explosive safe

operation

remove oxygen by inert gas



Westfalia Centrifuges for Explosion Proof Areas

• Simplified installation of a gear driven N2 machine:

operating water

10 to 20 mbar N2

Vent system

10-15 mbar N2

Nitrogen Control

Unit 25-30 mbar N2


Documents

Chemical Refining of Oils in Solvent Phase - Results Directaocs.files.cms-plus.com/Meetings/ChinaPresentation/Zeldenrust... · Top Degumming Crude oil. Condensate. Steam. M . Acid