Systems and methods for dewatering a slurry that includes lignocellulosic biomass and liquid

Patent metadata

Field	Value
Publication number	US-10919987-B2
Application number	US-201816033705-A
Country	US
Kind code	B2
Filing date	Jul 12, 2018
Priority date	Jul 13, 2017
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

The present disclosure relates to a dewatering systems, and related methods, that are adapted to convey lignocellulosic biomass to separate at least a portion of the water from a lignocellulosic biomass slurry and accumulate the dewatered lignocellulosic biomass. The dewatering system also includes a headspace occupied by a gas that is at a pressure that facilitates transferring the accumulated biomas into a pretreatment reactor having a pressurized headspace. Such a dewatering system can prevent undue mixing and backflow of gas (e.g., steam) from the pretreatment reactor.

First claim

What is claimed is:

1. A system for dewatering a lignocellulosic biomass slurry, wherein the system comprises:
a) a source of a lignocellulosic biomass slurry, wherein the lignocellulosic biomass slurry comprises:
i) lignocellulosic biomass; and
ii) water;

b) a dewatering system in fluid communication with the source of the lignocellulosic biomass slurry, and adapted to receive the lignocellulosic biomass slurry to separate at least a portion of the water from the lignocellulosic biomass slurry, wherein the dewatering system comprises at least a solids transfer device having a housing including an inlet and an outlet, wherein the solids transfer device is adapted to convey and accumulate dewatered lignocellulosic biomass proximal to the outlet of the solids transfer device, wherein the solids transfer device is configured to have a first headspace occupied by a gas is present at least at the inlet of the solids transfer device when conveying and accumulating dewatered lignocellulosic biomass, wherein the first headspace is at a first pressure; and
c) at least one vessel in fluid communication with the outlet of the solids transfer device, wherein the vessel is configured to receive the accumulated dewatered lignocellulosic biomass and process the dewatered lignocellulosic biomass, wherein the vessel has a second headspace that is occupied by a gas that is at a second pressure, wherein the second pressure is greater than atmospheric pressure when receiving the accumulated dewatered lignocellulosic biomass, and wherein the first pressure has a value that inhibits the gas in the vessel from flowing back through the solids transfer device.

2. The system of claim 1 , wherein the first pressure is substantially the same as or greater than the second pressure.

3. The system of claim 1 , wherein the source of the lignocellulosic biomass slurry comprises one or more pumps adapted to pump the lignocellulosic biomass slurry via one or more pipes in fluid communication with the dewatering system, wherein each pump is configured to pressurize the lignocellulosic biomass slurry above atmospheric pressure.

4. The system of claim 3 , further comprising one or more vessels in fluid communication with the one or more pumps, wherein each vessel is adapted to combine lignocellulosic biomass and an aqueous liquid to form the lignocellulosic biomass slurry.

5. The system of claim 4 , wherein the one or more vessels are adapted to have its contents exposed to atmospheric conditions.

6. The system of claim 1 , wherein at least a portion of the gas present at the first pressure in the first headspace at the inlet of the solids transfer device can be supplied from gas entrained in the source of the lignocellulosic biomass slurry.

7. The system of claim 1 , further comprising a source of gas in fluid communication with the dewatering system to provide the gas in the first headspace at the first pressure, wherein the source of the gas comprises one or more gas pipes coupled to the dewatering system.

8. The system of claim 1 , wherein the dewatering system further comprises an enclosed screen device that includes a screen having a plurality of openings and the first headspace above the screen; wherein the plurality of openings permit liquid to pass through to separate at least a portion of the water from the lignocellulosic biomass slurry; wherein the screen has a first end and a second end and is positioned so that the first end is above the second end relative to horizontal and so that the screen is at an angle greater than zero relative to horizontal; wherein the enclosed screen device is adapted to receive the lignocellulosic biomass slurry at the first end of the screen so that the slurry flows down and across the screen to separate at least a portion of the water from the lignocellulosic biomass slurry and form a first dewatered lignocellulosic biomass comprising residual water and lignocellulosic biomass that can be fed to the inlet of the solids transfer device; and wherein the solids transfer device is in fluid communication with the enclosed screen device.

9. The system of claim 8 , wherein the solids transfer device housing comprises a barrel member having the inlet at one end and the outlet at the opposite end, wherein the inlet is adapted to receive the first dewatered lignocellulosic biomass at the first pressure, wherein the solids transfer device is adapted to convey the first, dewatered lignocellulosic biomass through the barrel member to separate at least a portion of the residual water from the first, dewatered, lignocellulosic biomass and accumulate a second dewatered lignocellulosic biomass proximal to the outlet of the solids transfer device.

10. The system of claim 8 , further comprising a source of gas in fluid communication with the enclosed screen device, wherein the enclosed screen device is adapted to receive the gas so that the gas can occupy the first headspace above the screen at the first pressure.

11. The system of claim 8 , wherein the enclosed screen device comprises a gravity screen having a screen opening size of about 0.25 inches or less.

12. The system of claim 9 , wherein the barrel member comprises:
a) a screw section proximal to the barrel inlet;
b) a rotatable screw disposed within the screw section; and
c) an accumulation section proximal to the barrel outlet.

13. The system of claim 12 , further comprising a screen positioned at least in the screw section between the barrel member and the screw, wherein the screen is adapted to permit at least a portion of the residual water to be separated from the first, dewatered lignocellulosic biomass as the screw conveys the first, dewatered lignocellulosic biomass through the barrel member.

14. The system of claim 1 , wherein the lignocellulosic biomass comprises ground corn stover.

15. The system of claim 14 , wherein the ground corn stover has an average particle size such that at least 80 percent of the ground corn stover passes through a screen having one inch openings.

16. The system of claim 1 , wherein the first and second pressure are in the range from 20 to 200 psig; wherein first pressure is the same as or greater than the second pressure.

17. The system of claim 16 , wherein the first pressure is greater than the second pressure, and wherein the difference between the first pressure and the second pressure is 5 psi or less.

18. The system of claim 1 , wherein the at least one vessel is a pretreatment reactor.

19. The system of claim 18 , wherein the pretreatment reactor comprises a hydrolysis reactor operating at conditions to hydrolyze one or more polysaccharides in the lignocellulosic biomass.

20. The system of claim 19 , wherein the conditions comprise exposing the lignocellulosic biomass to an aqueous liquid at a temperature in the range from 245° F. to 350° F. and a pH in the range from 0.5 to 3.0 for a time period in the range from 0.5 to 5 hours.

Assignees

• Poet Res Inc

Inventors

• Carlson David Charles

Classifications

• C13K1/02 Primary

  obtained by saccharification of cellulosic materials (manufacture of fodder A23K10/32) · CPC title

• Y02E50/10

  Biofuels, e.g. bio-diesel · CPC title

• C02F11/125

  using screw filters · CPC title

• C02F11/121

  by mechanical de-watering · CPC title

• C02F2103/26

  from the processing of plants or parts thereof · CPC title