Subcritical water assisted oil extraction and green coal production from oilseeds
Provided herein are methods of optimizing energy recovery from oilseeds. The methods disclosed provide at least the ability to swell oilseeds and disrupt the cell walls (hulls) without changing the functionality and quality of oil; the process integration of oil extraction and green coal production to maximize the energy recovery in the form of crude oil and green coal from oilseeds; and heat integration during processing stages including subcritical water pretreatment, oil extraction, and subcritical water carbonization to minimize the process heat requirement.
1. A process for optimizing energy recovery from an oilseed comprising:
pretreating whole oilseeds with subcritical water at a pretreatment temperature;
separating pretreated oilseeds from a pretreated liquid phase; and
extracting oil from the pretreated oilseeds using an organic solvent.
2. The process of claim 1 , wherein the pretreatment temperature is between about 180° C. and 220° C.
3. The process of claim 1 , wherein pretreating occurs for a period between 5 minutes and 60 minutes.
4. The process of claim 1 , wherein the whole oilseeds are one or more of cotton seeds, rapeseeds, mustard seeds, jathopha seeds, sunflower seeds, safflower seeds, tobacco seeds, sesame, soybeans, flaxseeds, and canola seeds.
5. The process of claim 1 , wherein the organic solvent is selected from n-hexane, ethanol, methanol, chloroform, acetone, dichloromethane, and petroleum ethers.
6. The process of claim 1 further comprising:
separating a solid phase from the oil after extraction;
producing green coal from the solid phase with subcritical water carbonization of the solid phase at a carbonization temperature.
7. The process of claim 6 further comprising:
producing green coal also from the pretreated liquid phase with subcritical water carbonization of the liquid phase at the carbonization temperature.
8. The process of claim 6 , wherein the pretreatment temperature is between about 180° C. and 220° C.
9. The process of claim 6 , wherein pretreating occurs for a period between 5 minutes and 60 minutes.
10. The process of claim 6 , wherein the whole oilseeds are one or more of cotton seeds, rapeseeds, mustard seeds, jathopha seeds, sunflower seeds, safflower seeds, tobacco seeds, sesame, soybeans, flaxseeds, and canola seeds.
11. The process of claim 6 , wherein the carbonization temperature is between about 220° C. and 300° C.
12. The process of claim 1 further comprising:
separating a solid phase from the oil after extraction;
producing green coal from the solid phase and from the pretreated liquid phase with subcritical water carbonization of the solid phase and the pretreated liquid phase at a carbonization temperature and a carbonization pressure.
13. The process of claim 12 , wherein the carbonization temperature is between about 220° C. and 300° C.
14. The process of claim 12 , wherein the carbonization pressure is about 1220 psi.