Efficient methods and compositions for recovery of products from organic acid pretreatment of plant materials

1. A method for producing a desolventized cellulosic pulp containing less than 2% organic acids, the method comprising the steps of:

a) drying a cellulosic pulp produced from organic acids pretreatment of plant material in a dryer to remove the organic acids to a content of 3% to 18%, calculated from the total weight of the dried cellulosic pulp, and

b) capturing vapor released from the dryer for use in the extraction liquor concentration system and other organic acids pretreatment operational systems as a source of thermal energy, and

c) condensing the captured vapor in the extraction liquor concentration system to form a first phase of the organic acids solution of the organic acids pretreatment process, or optionally, using the vapor to provide thermal energy to additional operational steps within the organic acids pretreatment process, and

d) using direct steam in a desolventizer to further remove the organic acids from the cellulosic pulp, and

e) condensing the organic acids in the vapor released from the desolventizer, to obtain a second phase of organic acids solution of the organic acids pretreatment process.

2. The method according to claim 1 , wherein the organic acids of the process comprise a mixture of formic acid, acetic acid and water.

3. The method according to claim 1 , wherein the organic acids of the process comprise a mixture of formic acid, acetic acid, furfural and water.

4. The method according to claim 1 , wherein the organic acids of the process comprise a mixture of formic acid, furfural and water.

5. The method according to claim 1 , wherein the organic acids of the process comprise a mixture of formic acid and water.

6. The method according to claim 1 , wherein the dryer of the process is a bulk dryer.

7. The method according to claim 6 , wherein the bulk dryer is selected from the group consisting of tube dryer, pneumatic dryer and rotary disc dryer.

8. The method according to claim 7 , wherein the bulk dryer is a tube dryer.

9. The method according to claim 1 , wherein the dryer of the process is operated at a temperature of 80° C. to 160° C.

10. The method according to claim 1 , wherein the first phase of the organic acids solution of the organic acids pretreatment process comprises an organic acids content of 50% to 95%, total weight relative to the first phase of organic acids solution recovered in step c) of the process.

11. The method according to claim 1 , wherein the first phase of organic acids solution recovered in step c) of the process is reused in the organic acids pretreatment process.

12. The method according to claim 1 , wherein the desolventizer uses direct steam at a temperature of 90° C. to 130° C.

13. The method according to claim 1 , wherein the second phase of organic acids solution of the organic acids pretreatment process comprises an organic acids content of 5% to 60%, total weight relative to the second phase of organic acids solution in step e) of the process.

14. The method according to claim 1 , wherein the second condensation system to recover the organic acids in step e) of the process comprises 1 to 3 condensers.

15. The method according to claim 1 , wherein the second condensation system to recover the organic acids in step e) of the process comprises 2 condensers.