OPEX in Crushing
Optimizing Heat Recovery
16th Latin American Congress on Fats & Oil ASAGA
Rosario – ARGENTINA / Oct 31 - Nov 4 (2015)
Desmet Ballestra Group, Zaventem, Belgium Represented by David de Schaetzen
Heat recovery in Crushing : in case of Soya
Soya Seed
Cleaning & Weighing Bean heater/dryer (Jet Dryer) Primary dehulling Secondary dehulling Flaking
Extraction Desolventiser Dryer / Cooler Distillation
PREPARATION EXTRACTION
Soya Flow sheet / Preparation Scale, cleaner, Destoner
Bean-heater
(Jet dryer)
Primary Dehulling
Secondary Dehulling
Bean Heater : tube module
Design for heating steam (0,5 barg)
Width: 3300 mm
Length: 3300 mm
Height: 1000 mm
Surface: 200 m2
New: Plate Modules
Width: 3300 mm
Length: 3300 mm
Height: 1000 mm
Surface: 400 - 500 m2
Optimal for lower temperature streams
… Hot water …
Heat Recovery from Dryer in Extraction : with RTD
29
P29
10
9
8C
Steam
LIC
make-up water
Hexane vapour to 60A
MEAL FROM EXTRACTOR
FINISHED MEAL
14A
8D/ADryer 13A
Cooler 13B
14B
8D/B
Steam
36A
36B
Ambiant air
DIMAX DT
Rotary tube Dryer (RTD)
Rotary tube Cooler (RTC)
Why does it dry so well, versus Stack Dryer ?
94A
8C
Meal Inlet 105°C
Meal Outlet 65 - 75°C
Air Inlet 140°C
Air Outlet 65°C
Steam
Meal Inlet 105°C
Air Outlet 95°C
Air Inlet 20°C
Meal Outlet 65 - 75°C
Steam
Rotary dryer Stack dryer
Counter-Current ! Heated by tubes !
(What reduces air flow requirement)
Psychrometric Chart Psychrometric chart
0
10
20
30
40
50
60
70
80
90
100
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
kg water/ dry air
Tem
pera
ture
°C
100% 80% 60%
Rotary Dryer
1.3
95°C
Vertical Dryer
65°C
0.16 Kg Water / kg Air
Stack Dryer versus Rotary Tube
Rotary dryer Stack dryer
94A
8C
Meal Inlet 105°C
Meal Outlet 65 - 75°C
Air Inlet 140°C
Air Outlet 65°C
Steam
Meal Inlet 105°C
Air Outlet 95°C
Air Inlet 20°C
Meal Outlet 65 - 75°C
Steam
Rotary dryer :
8” x less air requirement ! less KW ! Higher outlet temperature (65C 95°C) !!! possible heatrecovery !!!
1,3 kg water / kg dry air
0,16 kg water / kg dry air
Heat Recovery via Hot water Loop : Soya
705 S
P13/20
85 °C
75 m3/h
95 °C 80 % HR
Expansion vessel
65 °C 100 % HR
P13/29
5 m3/h Effluent 3 m3/h
13/20
Steam
Condens
Condens
705
705
60 °C Steam
Condensate
E-comyzer
Soya Steam consumption
Where Conditions kg steam /T %
1A) Seed Pre Heating From 20 to 65°C 45 17%
1B) Seed Drying From 13 to 10,5% 35 13%
3) Toasting At 72°C 125 46%
4) Distillation 25% miscella 30 11%
5) Meal Drying with Rotary dryer from 18 to 13% 35 13%
Total 270 100%
6) Ecomiser (*) ..30.. ..11..%
Total net 240-235 89-87%
(*) Exact steam saving depends on Seed Temperature and Moisture
Heat recovery in Crushing : in case of Rapeseed
Heatreceovery within preparation between Cooker & Pre-conditioner…
Heat recovery in Crushing : in case of Rapeseed
Rape Seed
Cleaning & Weighing Pre-Conditioning Flaking Cooking Press Cake crisper
Extraction Desolventiser (No dryer) / Cooler Distillation
PREPARATION EXTRACTION
Heat recovery in Crushing : in case of Rapeseed
1
2
From 10°C to 65°C
From 60°C to 105°C and from 8% to 4%
Conditioning
Flaking
Cooking
Pressing
Cake Cooling
Heat Recovery via Hot water Loop : Rapeseed
E-comyzer
705 S
P2720
Steam
Condens
Seeds from
Storage
45 m3/h
95 °C 80 % HR
80 °C
Expansion vessel
60 °C 100 % HR
P2720
5 m3/hEffluent 3 m3/h
Condensate 8 bar from
Cooker 180°C
Condensate 100°C
Hot Oil 23 TPH
95°C
Cold Oil 23 TPH
70°C
SOLEX
40 °C
40 °C
75 °C
1
2
3
Conditioning
Cooking
How to optimize Energy ? : Toaster DT
Efficient DT design to optimize DT Vapor
Temperature.
Use of Pre-Desolventizing Tray
Use of FlashTray = heatrecovery
How to optimize Energy ? : Dimax® DT
Predesolventizing - 55..80°C (No direct steam, steam saving in DC)
Desolventizing - 80 ..100°C (Direct steam, 90% solvent evaporated)
Stripping > 100°C (Direct steam)
Flash Tray (Steam Drying) 7TH TRAY
6TH TRAY
5TH TRAY
4TH TRAY
8TH TRAY
1ST TRAY
3R D TRAY
2ND TRAY
Steam
How to optimize Energy ? : Dimax® DT
Desolventizing & Stripping
Accurate level control with rotary valve Stripping vapour through Screen
DT Vapor Temperature : From 80°C to 75°C = 12,5 kg/T steam saving
7TH TRAY
6TH TRAY
5TH TRAY
4TH TRAY
8TH TRAY
1ST TRAY
3R D TRAY
2ND TRAY
Steam
EFFICIENT Design
Heat recovery : Dimax® DT
FlashTray (Steam Drying)
Purpose is to both : • dry the meal to save DC steam • further reduce hexane residual
Water (& Hexane) vapor captured via steam ejector for heat recovery
7TH TRAY
6TH TRAY
5TH TRAY
4TH TRAY
8TH TRAY
1ST TRAY
3R D TRAY
2ND TRAY
Steam
How to optimize Energy ? : Distillation
Maximize Heat recovery & efficient design ! Big 1st Evaporator (Economiser).
Motive steam of final oil dryer = Oil stripping &
hexane pre-heating
Other steam saving : • Heat recovery Miscella / Hot Oil… • Oil stripper - Sieve tray design • Use of Flash Steam from condensate
Maximize heat recovery : Distillation
1 st Stage evaporator - economiser
DT vapor is used to evaporate hexane in miscella up to outlet concentration :
80-90% Oil / 10-20% Hexane
Important heating surface
DT Vapor
Condensed DT Vapor
Miscella 25% Oil
Miscella >80% Oil
Maximize heat recovery : Distillation
Motive steam of final Oil Dryer
Steam
Oil Stripper
Vacuum Pre-Condenser =
Hexane pre-heater
Hexane (Vapour) Vacuum Condenser
Steam Ejector (Oil Dryer)
Condensate Water
Hexane (Liq)
Hexane Final Heater
Hexane to EXTRACTOR
Steam
Steam + Hexane