Multi-reaction process for forming a product gas from solid carbonaceous material

Patent metadata

Field	Value
Publication number	US-2017301938-A1
Application number	US-201715637253-A
Country	US
Kind code	A1
Filing date	Jun 29, 2017
Priority date	Jun 2, 2009
Publication date	Oct 19, 2017
Grant date	—

Abstract

A direct carbonaceous material to power generation system integrates one or more solid oxide fuel cells (SOFC) into a fluidized bed gasifier. The fuel cell anode is in direct contact with bed material so that the H 2 and CO generated in the bed are oxidized to H 2 O and CO 2 to create a push-pull or source-sink reaction environment. The SOFC is exothermic and supplies heat within a reaction chamber of the gasifier where the fluidized bed conducts an endothermic reaction. The products from the anode are the reactants for the reformer and vice versa. A lower bed in the reaction chamber may comprise engineered multi-function material which may incorporate one or more catalysts and reactant adsorbent sites to facilitate excellent heat and mass transfer and fluidization dynamics in fluidized beds. The catalyst is capable of cracking tars and reforming hydrocarbons.

First claim

What is claimed is:

1 . A method of producing a final product gas from solid carbonaceous material, comprising:
(a) providing a first stage gasifier having a plurality of feedstock inlets and a fluidized bed maintained at a temperature ranging from 600° C. to 1,000° C., the fluidized bed including an enhanced char conversion zone proximate to the base of the gasifier, a drying and devolatilization zone located above the char conversion zone, and a dense fluid bed zone above the drying and devolatilizing zone; (b) shredding and initially drying said solid carbonaceous material; (c) after step (b), introducing, through said plurality of feedstock inlets, the solid carbonaceous material into the drying and devolatilizing zone of the fluidized bed; (d) introducing superheated steam, CO2, and O2 into the fluidized bed; (e) drying and devolatilizing a portion of the solid carbonaceous material within the fluidized bed to produce char, H2O, initial H2, initial CO, initial CO2, CH4, C2+condensable vapors, and tars; (f) forming a product gas comprising char, H2O, H2, CO, CO2, CH4, C2+condensable vapors, and tars by:
(f1) reacting a first portion of the superheated steam with a first portion of carbon contained within the solid carbonaceous material to produce first additional H2 and first additional CO;
(f2) reacting a second portion of the superheated steam with the first additional CO produced in step (f1) to produce second additional H2 and first additional CO2;
(f3) reacting a portion of the first additional H2 and/or a portion of the second additional H2 with a second portion of carbon contained within the solid carbonaceous material to produce second additional CO2;
(g) removing char from the product gas to thereby produce a first stage product gas comprising:
(g1) H2O, H2, CO, CO2, CH4, C2+condensable vapors, and tars produced in step (e),
(g2) first additional H2 and first additional CO produced in step (f1),
(g3) second additional H2 and first additional CO2 produced in step (f2), and
(g4) second additional CO2 produced in step (f3);
(h) gasifying the char that has been removed, to produce second stage product gas and ash; (i) separating the ash from the second stage product gas; and (j) combining the first stage product gas and the second stage product gas to form said final product gas.

2 . The method according to claim 1 , comprising:
in step (b), shredding the solid carbonaceous material to a top size of 25 mm.

3 . The method according to claim 3 , comprising:
in step (b), drying the solid carbonaceous material to a moisture content of about 10%.

4 . The method according to claim 3 , comprising:
in step (b), drying the solid carbonaceous material with flue gas.

5 . The method according to claim 1 , comprising operating the first stage gasifier at a pressure ranging from 1 to 15 bar gauge.

6 . The method according to claim 1 , wherein the first stage gasifier also outputs H2S, COS, HCl, NH3, HCN, and metal vapors.

7 . The method according to claim 1 , further comprising providing a fluidized bed of bed particles within the first stage gasifier.

8 . The method according to claim 7 , wherein the bed particles are comprised of one or more from the group consisting of porous bed particles, ceramic bed particles, and alumina bed particles.

9 . The method according to claim 7 , wherein the bed particles are comprised of engineered multi-function particles including alumina having catalytic properties configured to crack tars and reform hydrocarbons.

10 . The method according to claim 1 , comprising:
introducing one or more from the group consisting of superheated steam, air, CO2, and O2 into the first stage gasifier, via a distributor provided at the base of the first stage gasifier.

11 . The method according to claim 1 , further comprising:
introducing the product gas into a freeboard area occupying an upper portion of the first stage gasifier above the fluidized bed; and evacuating the product gas from the first stage gasifier, via the freeboard area.

12 . The method according to claim 11 , comprising:
introducing the product gas into a cyclone located in the freeboard area, the cyclone configured to separate or recover solids from the product gas; and returning solids separated out from the product gas within the cyclone, to the fluidized bed.

13 . The method according to claim 1 , comprising:
starting up fluidized bed operations and/or controlling dense fluid bed temperature, using at least two indirect heating elements which protrude into the fluidized bed of the first stage gasifier from a sidewall.

14 . The method according to claim 13 , wherein the indirect heating elements are comprised of pulse combustion heaters and/or electrical heaters.

15 . The method according to claim 1 , comprising:
in step (h), gasifying the char with oxygen or air.

16 . The method according to claim 1 , further comprising:
after step (j), removing tars from the final product gas using a solvent.

17 . The method according to claim 1 , further comprising:
after step (j), burning at least a portion of the final product gas to form flue gas.

18 . The method according to claim 1 , further comprising:
after step (j), cooling the final product gas to generate steam.

19 . The method according to claim 1 , further comprising:
after step (j), removing CO2 from final product gas.

20 . The method according to claim 1 , further comprising, after step (j):
removing tars from the final product gas using a solvent; burning at least a portion of the final product gas to form flue gas; cooling the final product gas to generate steam; and removing CO2 from final product gas.

Assignees

• Thermochem Recovery Int Inc

Inventors

• Chandran Ravi

Classifications

• C01B3/42

  using moving solid particles, e.g. fluidised bed technique · CPC title

• C10J3/466

  Entrained flow processes · CPC title

• C01B2203/0283

  containing a CO-shift step, i.e. a water gas shift step · CPC title

• C01B3/12

  by reaction of water vapour with carbon monoxide · CPC title

• C01B2203/0811

  by combustion of fuel · CPC title