Optimizing Continuous Deodorization for Quality and Energy

Transcription

1 106th AOCS Annual Meeting Update on New Technologies and Processes in Oils and Fats Optimizing Continuous Deodorization for Quality and Energy Jim Willits, Sr. Consultant Desmet Ballestra North America

2 Brief Deodorization History 2

3 History of Deodorization Pre-deodorization Oil chosen for how it smelled, tasted, and its consistency, durability and availability The demand for a extender for butter/lard resulted in the development of margarine, which in turn created the need to be able to reduce the flavor in available oils and fats. 3

4 History of Deodorization 1850s First patents on atmospheric, directly heated, no sparge gases and carbon steel construction 1890s First batch deodorizers with sparge gasses and direct heat. Still carbon steel construction 4

5 History of Deodorization 1920s French engineers added: Vacuum Higher temperatures Non-oxidizing materials of construction There was a need developing in the US to replace animal fat in shortening with cottonseed oil 5

6 History of Deodorization 1920s David Wesson developed a deodorizer which used: Indirect heat High temperature under vacuum This unit offered capability to reduce the strong flavor of cottonseed oil 6

7 History of Deodorization c.1948 Around 1948 the Girdler/Votator Companies developed a true Semi Continuous Deodorizer A. E. Bailey developed a deodorizer with vertical stacked trays that could hold very good vacuum in the presence of sparge steam Dowtherm was introduced which allowed indirect heating with a low pressure vapor 7

8 History of Deodorization Benjamin Thurman of Humko Products developed a deodorizer with seven horizontal cylinders (four to deodorize and three for cooling) 1960s Votator developed the steam lift pump which allowed the use of deeper trays and reduced the deodorization time from 90 minutes to 30 minutes 8

9 History of Deodorization 1970s Simon-Rosedowns introduced the thermosyphon, which offered the ability to exchange heat within the deodorizer vessel The growing palm oil industry gave rise to the continuous deodorizer 9

10 History of Deodorization 1970s Frank Sullivan developed scrubbers to remove fatty material from the vapor stream P & G developed thin film strippers 1980s Alfa Laval championed the use of packed columns in palm oil deodorization 10

11 History of Deodorization 1990s Desmet brought the ice condensing vacuum system into the market, which allowed economical low vacuum High pressure steam started to replace terminal and Dowtherm as heating media for deodorization 11

12 History of Deodorization 2010s Desmet Ballestra adds flexibility to generation of hot water for sharing the BTU s generated in deodorization with other refinery and seed preparation processes. Improvements made in the recovery of Tocopheral as price's for this products increase significantly. 12

13 Deodorization Equipment 13

14 R&D Science behind Technology Bench/Pilot/Full Scale 14

15 Objectives of Deodorization Deodorization is a crucial refining stage with a big impact on the refined oil quality. Its has three main objectives: 1. Stripping of volatile components such as free fatty acids (in case of physical refining), valuable minor components (tocopherols, sterols, etc.) and contaminants (pesticides, light PAH, etc.); 2. Actual deodorization by removal of different offflavors; 3. Thermal destruction of pigments (so-called heat bleaching). 15

16 Factors Affecting Oil Quality Seed Variety Growing Conditions Harvesting Conditions Extraction Conditions Degumming and Neutralizing Bleaching Deodorizing Storage 16

17 Factors Affecting Deodorizing Quality Temperature Time Pressure Steam rate Air Leaks Heating and Cooling under vacuum Quality of incoming oil 17

18 Selection Process We start with 3 base deodorizer designs: Continuous flow Continuous flow Packed Stripper Semi-continuous flow From these three base designs, we add options to meet specific needs 18

19 Three Base Deodorizer Designs Qualistock+ TM Qualistock+ FS TM Multistock TM 19

20 Deodorizer Designs: Qualistock+ Continuous flow deodorizer Deodorization in trays (deep or shallow) Up to three stock changes per day Ideal for internal oil/oil heat recovery Internal spray/packing vapor scrubber Low-temp, long-time deodorizing, or High-temp, short-time deodorizing High-Low or Low-High temp deodorizing 20

21 Qualistock + New Configuration All major sections combined into single vessel Reduced losses and improved distillate quality Splash oil eliminated Low energy consumption 21

22 Deodorizer Designs: Qualistock+ FS Continuous flow deodorizer Fatty acid stripping in packing, then deodorization and heat bleach in tray Up to three stock changes per day Ideal for internal oil/oil heat recovery Internal packing-type vapor scrubber Popular for palm/soy/canola physical refining Popular in North America for high-temp, short deodorization-time, soy/canola oil deodorization 22

23 Deodorizer Designs: Qualistock+ FS 23

24 Deodorizer Designs: Multistock Semi-continuous flow deodorizer Deodorization in deep tray (s) Multiple stock changes per day (10 or more possible) Minimum stock change contamination Thermosyphon heat recovery (Single or Double) Internal or external spray vapor scrubber Popular at multiple feedstock plants 24

25 Deodorizer Designs: Multistock 25

26 Deodorizing Options 26

27 Deodorizing Options: Packed Columns Utilizes very high surface area of structured packing to create a thin film for excellent steam stripping Minimizes time at high temp for heat sensitive oils Allows high or low tocopherol stripping (soy) Deodorizing steam can be re-used for stripping Insufficient time, if used alone, to remove less volatile compounds Insufficient time, if used alone, for thorough heat bleaching Pressure drop needs to compensated in scrubber and vacuum system design 27

28 Deodorizing Options: Packed Columns 28

29 Deodorizing Options: Deep Trays Utilize steam lift pumps to continuously expose a thin film of oil to the vacuum Excellent steam stripping mechanism Long residence time for removing less volatile compounds that reduce oil stability Long residence time for heat bleach effect Most cost effective residence time Long residence time can increase trans formation 29

30 Deodorizing Options: Deep Trays 30

31 Deodorizing Options: Shallow Trays Utilizes sparge steam pipes to regenerate the surface in contact with vacuum Multiple shallow trays can add residence time for removing less volatile compounds that reduce oil stability More shallow trays are more expensive than fewer deep trays 31

32 Deodorizing Options: Shallow Trays 32

33 Deodorizing Options: Dual-Tem Packing/Tray High-Low Packing section operates at high temp (500 F) and tray operates at low temp (446 F) after a quick quench Minimizes trans fatty acid formation Provides high tocopherol removal (soy) Reduced heat bleach effect 33

34 Deodorizing Options: Dual-Temp to reduce trans fatty acids FORMATION OF TRANS ISOMERS IN SOYBEAN OIL AT DIFFERENT TEMPERATURES %Trans isomer minutes 0 20 minutes Temperature deg C minutes 0 minutes Time 34

35 Deodorization Conditions Conditions Chemical Physical U.S. Europe Europe Temperature ( C) Pressure (mbar) Sparge steam (%) Time (min) Final FFA (%)

36 Chemical versus Physical Refining Pressure Stripping Steam Booster Steam Fuel Booster Deodorizer (kg/tone oil) (kg/tone oil) (kg) Chemical Refining 2.5 mbar 3 mbar mbar 2 mbar Physical Refining 2.5 mbar 3 mbar mbar 2 mbar

37 Heat Recovery Options 37

38 Heat Recovery Options: Oil/Oil Internal Used with continuous deodorizers Excellent heat recovery (80-90%) Heat exchange under vacuum Reduced installation cost No need for an outside heat sink 38

39 Heat Recovery Options: Oil/Oil Internal 39

40 Heat Recovery Options: Oil/Oil External Used with continuous deodorizers Excellent heat recovery (80-90%) No need for an outside heat sink Shorter stock change time (1 hour) Potential oxidation of oil (not under vacuum) Higher installation & maintenance costs Less of a turn down potential 40

41 Heat Recovery Options: Oil/Oil External Plate-type Huge Shell & Tube-type 41

42 Heat Recovery Options: Thermosyphon (single or double) Used with semi-continuous deodorizers Simple no pumps required No external heat sink required Single has low heat recovery (single: 40-45%) Double has medium heat recovery (double: 60-65%) Heat exchange under vacuum Rather high capital cost for heat exchanged 42

43 Heat Recovery Options: Thermosyphon (single or double) 43

44 Heat Recovery Options Low Pressure Steam Generation Used with semi-continuous deodorizers Produce heat recovery oil/oil (high-low dual-temp quench) Produce 30 psig steam after thermosyphon Heat exchange under vacuum Good heat recovery (80-85%) 44

45 Heat Recovery Options: Hot Water Generation Used with semi-continuous deodorizers Produce 195 F water for heating tanks, boiler feed water, seed heating Excellent heat recovery (90-95%) Requires a hot water utilization system 45

46 Vapor Scrubbing Options 46

47 Vapor Scrubbing Options: External Spray Contact Low fatty acid carry-over Minimizes deodorizer tower height Works with any deodorizer design Requires expensive external ducting and added installation cost Increase in size of vacuum system due to increased pressure loss 47

48 Vapor Scrubbing Options: External Spray Contact Booster steam Vacuum unit Scrubber water LC Fatty acids 48

49 Vapor Scrubbing Options: Internal Spray Low fatty acid carry-over Eliminates expensive external ducting and installation cost Works well at the base of the deodorizer Increases deodorizer tower height 49

50 Vapor Scrubbing Options: Internal Spray Vacuum connection FA Scrubbing 823 Demister 814 FAD 50

51 Vapor Scrubbing Options: Internal Packing Low fatty acid carry-over Eliminates expensive external ducting and installation cost Works well at the top of the deodorizer Increases deodorizer tower height 51

52 Vapor Scrubbing Options: Internal Packing m m m m

53 Deodorizer Distillates Composition Chemical Refining Physical Refining Neutral Oil 25-33% 5 10% Fatty Acids 33 50% 80 85% Unsaponifiable matter % 5 10 % Tocopherols 6 15% 2 5 % Tocopherols / Sterol Recovery 53

54 Vacuum System Options 54

55 Vacuum System Options: Dirty Water / Steam Jet System Least expensive initial cost Optimizes cooling water temperature High motive steam (approx. 9:1 ratio) High waste water discharge Dirty cooling water fouling & odor problem at tower 55

56 Vacuum System Options Dirty Water / Steam Jet System 56

57 Vacuum System Options Clean Water / Steam Jet System Relatively low initial cost Clean cooling water little fouling or odor Cooling temperature higher than cooling water Highest motive steam (approx. 10:1 ratio) Highest waste water discharge 57

58 Vacuum System Options: Clean Water / Steam Jet System 58

59 Vacuum System Options: Chilled Water / Steam Jet System Reduced motive steam (approx. 5:1 ratio) Reduced waste water discharge No ammonia required Additional energy to chill water Higher initial cost 59

60 Vacuum System Options: Chilled Water / Steam Jet System 60

61 Vacuum System Options: Sublimax Ice Condensing System Very low operating pressures made practical Motive steam reduced below 1:1 ratio Lowest net operating energy Lowest waste water volume Low ammonia hold-up in patented Sublimax system Higher electrical power for ammonia compressor Highest initial cost 61

62 62

63 Vacuum System Options: Sublimax Ice Condensing System From FA scrubber Condenser Cooling water Freeze condenser Compressor To de-aeration Separator Valve, open Valve, closed LP steam Vapour (vacuum) Refrigerant (ammonia) Condensate Non-condensable gases process vapor Melt vessel water ammonia 63

64 106th AOCS Annual Meeting Update on New Technologies and Processes in Oils and Fats Thank you for your attention! Jim Willits, Sr. Consultant Desmet Ballestra North America 64