chemical refining of oils in solvent phase - results...
TRANSCRIPT
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
GEA Mechanical Equipment
• 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
GEA Mechanical Equipment
• 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 3
GEA Mechanical Equipment
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
Renewable Resources - Chemical Refining of oils in solvent phase 4
GEA Mechanical Equipment
• 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?
Renewable Resources - Chemical Refining of oils in solvent phase 5
GEA Mechanical Equipment
Density meter
Miscella Refining
Miscella from Extractor Press Oil
Hexane
Optional: Miscella mixing
Renewable Resources - Chemical Refining of oils in solvent phase 6
GEA Mechanical Equipment
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
Renewable Resources - Chemical Refining of oils in solvent phase 7
GEA Mechanical Equipment
• 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
Renewable Resources - Chemical Refining of oils in solvent phase 8
GEA Mechanical Equipment
• 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
Renewable Resources - Chemical Refining of oils in solvent phase 9
GEA Mechanical Equipment
• 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 10
GEA Mechanical Equipment
• 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
Renewable Resources - Chemical Refining of oils in solvent phase 11
GEA Mechanical Equipment
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
Renewable Resources - Chemical Refining of oils in solvent phase 12
GEA Mechanical Equipment
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
Renewable Resources - Chemical Refining of oils in solvent phase 13
GEA Mechanical Equipment
• 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
Renewable Resources - Chemical Refining of oils in solvent phase 14
GEA Mechanical Equipment
• 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
Renewable Resources - Chemical Refining of oils in solvent phase 15
GEA Mechanical Equipment
• 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 in case of solvents
• Requirements for the use of equipment for explosive products
Overview
Renewable Resources - Chemical Refining of oils in solvent phase 16
GEA Mechanical Equipment
Explosion Triangle
Burning Substance
Explosive
Oxidator - Air atmosphere Burning Substance - Explosive gas dust Ignition Source - Equipment
Renewable Resources - Chemical Refining of oils in solvent phase 17
GEA Mechanical 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
Renewable Resources - Chemical Refining of oils in solvent phase 18
GEA Mechanical Equipment
Avoid Explosive Atmosphere
Explosive safe
operation
Burning Substance Non-Explosive Atmosphere
change process conditions
Burning Substance
Explosive safe
operation
remove oxygen by inert gas
Renewable Resources - Chemical Refining of oils in solvent phase 19
GEA Mechanical Equipment
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
Renewable Resources - Chemical Refining of oils in solvent phase 20