Crown Iron Works Company

Transcription

1 Crown Iron Works Company AOCS FUNDAMENTALS OF OILSEED AND EDIBLE OIL PROCESSING AND REFINING Fundamentals of Oils and Fats Processing- Deodorizer Design and Optimization Shanghai, China November 2014 Greg Waranica 1

2 Crown Contacts USA Greg Waranica or Derek Masterson Crown Iron Works Company Phone: Web: 2

3 Crown Contacts China Crown Asia Engineering (Wuhan) Co., Ltd Phone: +86 (27) Web: 3

4 Oils & Fats Refining Roadmap 4

5 Purpose of Deodorizing Improve odor, flavor, color and stability of oils and fats by removing or inactivating: Materials causing unpleasant odors or flavors (FFA, aldehydes & ketones) Unsaponifiables (tocopherol and sterols) Oxidative materials (peroxides) Color bodies (carotenoids) Toxic substances (pesticides & herbicides) Recovery of: Fatty acid Tocopherol 5

6 Typical Deodorizing Feedstock Quality Free Fatty Acid (FFA): 0.07% - 4% 0.07% to 0.1% for neutralized oils and fats 3% to 4% for palm oil and edible fats Phosphatides: 2-10 ppm P Moisture: < 0.1% Iron (Fe): < 0.2 ppm Unsaponifiables: 1.0% Soap: zero Impurities: zero 6

7 Types of Deodorizers Batch Semi-Continuous Continuous Trays Packed column (PC) 7

8 Batch Deodorizing Criteria Small capacity (< 30 tpd) Small batches of valuable oil Pilot plant Single vessel with one compartment for heating, deaerating, stripping, deodorizing and cooling 10 Ton Batch Deodorizer with Scrubber 8

9 Batch Deodorizing System 9

10 Semi-continuous Deodorizing Criteria Capacity ranging from 50 tpd to 800+ tpd Frequent stock changes (> 4 per day) Minimize cross contamination Single vessel; batches continuously in minute increments with separate compartments for deaerating heat recovery heating stripping deodorizing cooling with each batch flowing by gravity to the next compartment DiFlow Deodorizer with Ice Condensation Vacuum System DiFlow Deodorizer with Dual Thermo-Siphon Heat Recovery 10

11 Semi-continuous Tray Design-Deodorizing Single tray with deep oil bed for Deaerating Heat Recovery Heating Cooling FFA stripping Stripping and deodorizing done in the same tray Short packed column between heating and deodorizing tray Deodorizing trays Single tray with deep oil bed Multiple trays with shallow oil depth Oil is circulated within the deodorizing tray using eductor pumps Oil is agitated with steam in all trays 11

12 Semi-continuous Deodorizing System 12

13 Continuous Deodorizing Criteria Capacity ranging from 50 tpd to tpd Occasional stock changes (< 4 per day) Single vessel with multiple compartments or multiple vessels for deaerating heat recovery heating stripping deodorizing cooling a continuous, uninterrupted feed 600 TPD Tray Deodorizer 1200 DSPC Deodorizer 13

14 Continuous Deodorizer Many design options Tray Packed Column Single shell Single shell with bypass Double shell Number of vessels Single Multiple Heating/Cooling Under vacuum Under pressure 14

15 Continuous Tray Deodorizing System Heating and Cooling Under Vacuum 15

16 Continuous Packed Column Deodorizing System Heating and Cooling Under Vacuum 16

17 Continuous Packed Column Deodorizing System Heating and Cooling Under Pressure 17

18 Packed Column vs. Tray Advantages: Less stripping steam Smaller vacuum system (lower capital cost and less motive steam) Stripping steam does not increase as FFA increases (physical refining) Faster removal of FFA and other volatiles (possible to control tocopherol removal) Less transisomers formed at high temperature stripping of FFA or FFA stripped at lower temperatures more effectively (thin film) Independent stripping and heat bleaching sections allow stripping at a high temperature and heat bleaching at a lower temperature (additional heat exchanger required) Packed Column Tray 18

19 Packed Column vs. Tray Disadvantages: More sensitive to air infiltration (may be minimized) Increased co-mingling with residual oil during stock change (greater surface area) Packing fouls over time (cleaning frequency depends on oil quality to deodorizer and presence of air) Packed Column Tray 19

20 Bypassing Vapor Around the Packed Column Advantages Lower pressure (higher vacuum) in heat bleaching/heat recovery/cooling section(s) of deodorizer below packed column (Δ 2-3 mbar) Protects oil and packing from air Clean stripping steam Slightly lower heat loss from PC section with double shell (lower radiant loss) Disadvantages Slightly higher vessel or installation cost How? Separate duct from heat bleaching to scrubber Double shell Bypass around PC Double Shell PC 20

21 Design Topics Influence of Air on Product Quality Heating under Vacuum Cooling under Vacuum Post Deodorizing vs. Cooling under Vacuum External vs. Internal Heating & Cooling 21

22 Influence of Air on Product Quality How air affects deodorizing Reduces finished oil quality and increases fouling Oxidation and fouling increase exponentially as temperature increases More critical for packed column type designs if the packed column is not protected How to protect the oil and deodorizer Maximize phosphatide removal in neutralizing and bleaching Maximize air removal in deaeration Bypass vapor from heat bleaching around the packed column Separate stripping steam for the packed column No air in stripping steam Steam sealed manways to minimize air infiltration from leaking flanges 22

23 Maximizing Heat Recovery Type of Deodorizer Design Heat Loss ΔT Heat Recovery Semi- Continuous Single Thermosyphon 8ºC 14ºF 95ºC 203ºF 47% Semi- Continuous Double Thermosyphon 10ºC 18ºF 60ºC 140ºF 63% Continuous Internal Heat Recovery Coils 10ºC 18ºF 40ºC 104ºF 73% Continuous External Heat Recovery Plate Heat Exchangers 8ºC 14ºF 24ºC 75ºF 82% Assumptions: Energy required for deodorizing: 580 MJ/MT / 250 MBTU/Mlbs (30 240ºC / 86 80% efficiency) System radiation loss: 5-15ºC / 9-27ºF (varies with design & size) Net operating temperature: ºC / ºF 23

24 External HE s vs. Internal Coils Advantages: Higher heat recovery Design not limited by the deodorizer diameter or oil depth Each component designed for optimum performance of the system Plate heat exchangers (PHE) and spiral heat exchangers (SHE) require less surface area per unit of heat recovered and require less space No production down time for cleaning or service (standby PHE or SHE) Easier to service and clean straight tubes in external vessels or clean plate heat exchangers (CIP) than pigtail heating/cooling coils. No advantage if bayonet/u-tube style internal coils are used. 24

25 External HE s vs. Internal Coils Disadvantages: Efficiency decreases quickly as heat exchange surface of PHE or SHE is fouled; more gradual with S&T Larger floor space requirements (foot print) when compared to internal trays with pigtail or bayonet coils More piping and higher installation cost 25

26 Post Deodorizing vs. Cooling under Vacuum Advantages: Lower gas/oil/electrical consumption (greater heat recovery) No downtime for cleaning of coils or tubes (in-line spare) Disadvantages: Additional equipment with controls Larger floor space requirement (foot print) vs. internal cooling trays Post Deodorizing Internal Cooling Under Vacuum External Cooling Under Vacuum 26

27 Scrubbers Single scrubber FFA and tocopherol combined discharge Dual scrubber separate FFA and tocopherol discharges (concentrated byproducts) Tocopherol FFA 27

28 Vacuum System Considerations Vacuum Systems 4 stage direct contact (barometric) with dirty cooling tower 4 stage direct contact with closed loop 4 stage indirect contact (surface condenser) 3 or 4 stage direct contact with chilled loop 4 stage direct or indirect contact with ice condensing Considerations Capital cost Steam cost Electrical cost Effluent cost Cooling water cost Maintenance cost Equipment life & replacement cost Safety (ammonia) 28

29 Vacuum System Cost Comparison 29

30 4-Stage Direct Contact (Barometric) Vacuum Systems 30

31 4-Stage Indirect (Surface Cond) Vacuum System 31

32 Chilled Loop 3-Stage Direct Contact Vacuum System 32

33 Ice Condensing System for 4-Stage Vacuum System 33

34 What is Optimizing? Optimizing = Optimizing = Balancing Constantly Changing Demands to Maximize Profit Energy Quality Maintenance Production Optimizing Maximizing Each Parameter 34

35 Optimizing Deodorizing Begin at the beginning (seed, not crude oil) Deodorizing removes only some contaminants in the oil Deodorizing cannot overcome poor Seed quality Seed storage Preparation Extraction Oil storage Degumming Neutralizing Bleaching 35

36 How to Optimize Any Oilseed Process Understand the process and related operating costs Define targets Test process and establish product quality limits in Lab Start optimizing the process from the incoming seed or crude oil storage and handling Work on one parameter at a time Install the proper automation for your situation Keep records Be patient Make the necessary changes to operating conditions and equipment Review continuously 36

37 THANK YOU FOR YOUR ATTENTION 37