Oilseed crushing heat recovery process
An oilseed crushing process wherein the oilseeds are preheated to generate warm, soft oilseeds, then flakes are generated by flaking the warm, soft oilseeds. The flakes are then cooked by generating a hot vapor stream and hot flakes. The hot flakes are then prepressed to generate oil and a partially de-oiled cake. The partially de-oiled cake is solvent extracted to generate solvent laden oil and solvent laden meal. The hot, wet meal is then dried to generate oilseed meal and an additional hot vapor stream. The at least part of the preheating step to generate warm, soft oilseeds is accomplished using a hot liquid medium. The hot liquid medium is heated by a heat transfer mechanism that condenses at least one of the hot vapor streams generated during the flake-cooking step or the meal-drying step.
1. An oilseed crushing process including the steps of:
a) preheating the oilseeds to generate warm, soft oilseeds,
b) flaking the warm, soft oilseeds to generate flakes,
c) cooking the flakes, said cooking generating a first hot vapour stream and hot flakes,
d) prepressing the hot flakes to generate oil and a partially de-oiled cake,
e) solvent extracting the partially de-oiled cake to generate solvent laden oil and solvent laden meal,
f) desolventizing the solvent laden meal to generate hot, wet meal,
g) drying the hot, wet meal to generate oilseed meal and a second hot vapour stream, characterised in that at least a part the preheating of the oilseeds in step (a) is realised in a preheating mechanism using a hot liquid medium having a temperature of about 60- about 85° C., with said hot liquid medium being heated by a heat transfer mechanism forming a condensate from hot vapour from at least one of said hot vapour streams from step (c) or (g) to generate said hot liquid medium wherein said hot liquid medium is water.
2. The process according to claim 1 wherein said heat transfer mechanism comprises a tubular condenser, said tubular condenser being erected vertically.
3. The process according to claim 2 in which said tubular condenser comprises a plurality of tubes said hot vapour being condensed in said tubes.
4. The process according to claim 3 in which said hot vapour is introduced at the top of said tubes.
5. The process according to claim 4 in which the velocity of said hot vapour inside said tubes is at least 10 m/sec.
6. The process according to claim 3 in which at least a fraction of said condensate is recycled inside said tubes.
7. The process according to claim 6 in which said recycled condensate is introduced at the top of said tubes.
8. The process according to claim 1 in which the hot liquid medium is further heated by one or more heat exchangers.
9. The process according to claim 1 in which the oilseed is rapeseed.
10. The process according to claim 1 wherein said preheating mechanism comprises a plurality of cavities wherein said hot liquid medium flows through said cavities to heat said oilseeds via conductivity.
11. The process according to claim 10 wherein said cavities comprise hollow plates.
12. The process according to claim 10 further comprising recycling said hot liquid medium from said cavities to said heat transfer mechanism.
13. The process according to claim 12 wherein said heat transfer mechanism comprises a tubular condenser.