Two-stage biomass pyrolysis

Patent metadata

Field	Value
Publication number	US-10174258-B2
Application number	US-201715435990-A
Country	US
Kind code	B2
Filing date	Feb 17, 2017
Priority date	Feb 23, 2016
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

The present disclosure relates generally to a two-stage biomass pyrolysis processes that maximize pyrolysis vapor yield from a lignocellulosic biomass while being conducive to commercial-scale throughput of biomass. A lignocellulosic feedstock is first pyrolyzed in a reactor first stage comprising at least one auger at a temperature and residence time that produces pyrolysis vapors derived predominantly from cellulose and hemi-cellulose fractions of the feedstock. Partially-pyrolyzed feedstock from the reactor first stage is then pyrolyzed in a reactor second stage at a higher temperature for an additional residence time to produce additional pyrolysis vapors that are predominantly derived from lignin. Certain embodiments arrange multiple reactor first stages around a single reactor second stage.

First claim

We claim:

1. A process for pyrolyzing lignocellulosic biomass in a two-stage pyrolysis reactor, comprising the steps of:
a) pyrolyzing a lignocellulosic feedstock in a reactor first stage that is maintained at a temperature from 315° C. to 400° C., wherein the reactor first stage comprises at least one auger that conveys the lignocellulosic biomass feedstock through the reactor first stage from a first end portion toward a second end portion, for a lignocellulosic feedstock residence time ranging from 5 to 20 seconds, thereby producing a first product comprising a first condensable pyrolysis vapors and a first solids comprising partially-pyrolyzed feedstock and char;
b) passing the first product out of the reactor first stage via an interface located near the second end portion of the reactor first stage and directly into a reactor second stage that is maintained at a temperature in the range from 401° C. to 700° C.;
c) pyrolyzing the partially-pyrolyzed feedstock in the reactor second stage for a second feedstock residence time in the range from 30 seconds to 120 seconds to form a second condensable pyrolysis vapors that mixes with the first condensable pyrolysis vapors, and to form a second solids comprising char that mixes with the first solids to form combined solids;
d) separating the first and second condensable pyrolysis vapors from the combined solids in a space located within the top of the reactor second stage, wherein the first condensable pyrolysis vapors are removed from the pyrolysis reactor within five seconds after being produced by the pyrolyzing of step a), and the second condensable pyrolysis vapors are removed from the pyrolysis reactor within five seconds after being produced by the pyrolyzing of step c).

2. The process of claim 1 , wherein the terminal falling velocity of particles in the combined solids becomes greater than the upward local velocity of the first and second condensable pyrolysis vapors in the space at the top of the reactor second stage, thereby causing at least 99.5 wt. % of the combined solids to be retained in the reactor second stage.

3. The process of claim 1 , wherein the second pyrolysis reactor comprises a bed containing at least one catalyst that facilitates pyrolysis of the un-pyrolyzed biomass, facilitates upgrading of the second condensable pyrolysis vapors to a transportation fuel or fuel intermediate, or combinations thereof.

4. The process of claim 2 , wherein the at least one catalyst is added to the bed either continuously or intermittently via at least one catalyst inlet.

5. The process of claim 1 , wherein the first condensable pyrolysis vapors is derived predominantly from the pyrolysis of one or more of hemicellulose and cellulose, and the second condensable pyrolysis vapors is derived predominantly from the pyrolysis of lignin.

6. The process of claim 1 , further comprising contacting the combined first and second condensable pyrolysis vapors with at least one upgrading catalyst downstream from the reactor second stage to produce a biofuel, or an intermediate thereof.

7. The process of claim 1 , wherein the reactor first stage is maintained at a temperature in the range from 325° C. to 400° C.

8. The process of claim 1 , wherein the reactor second stage is maintained at a temperature in the range from 450° C. to 700° C.

9. The process of claim 1 , wherein the reactor second stage is maintained at a temperature in the range from 500° C. to 700° C.

10. The process of claim 1 , wherein the reactor second stage is maintained temperature that is at least 50° C. higher than the reactor first stage.

11. The process of claim 1 , wherein the reactor second stage is maintained temperature that is at least 100° C. higher than the reactor first stage.

12. The process of claim 1 , wherein the first condensable pyrolysis vapors are removed from the pyrolysis reactor within 3 sec after being produced by the pyrolyzing of step a), and the second condensable pyrolysis vapors are removed from the pyrolysis reactor within 3 sec after being produced by the pyrolyzing of step c).

13. The process of claim 1 , wherein the first condensable pyrolysis vapors are removed from the pyrolysis reactor within 1 sec after being produced by the pyrolyzing of step a), and the second condensable pyrolysis vapors are removed from the pyrolysis reactor within 1 sec after being produced by the pyrolyzing of step c).

14. The process of claim 1 , wherein more than one reactor first stage directly interfaces with the reactor second stage, each reactor first stage passing the first product directly into the reactor second stage.

Assignees

• Phillips 66 Co

Inventors

• Dalluge Dustin L
• Lusk Steven E
• Jones Samuel T
• Gorke Johnathan T

Classifications

• C10B57/06

  containing additives · CPC title

• Y02E50/14

  Cross-Sectional Technologies · mapped topic

• C10B53/02 Primary

  of cellulose-containing material (production of pyroligneous acid C10C5/00) · CPC title

• Y02P20/145

  the feedstock being materials of biological origin · CPC title

• C10B49/16

  with moving solid heat-carriers in divided form · CPC title