Method of purification of biomass syngas under negative pressure

Patent metadata

Field	Value
Publication number	US-9409775-B2
Application number	US-201414314011-A
Country	US
Kind code	B2
Filing date	Jun 24, 2014
Priority date	Dec 29, 2011
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A method for purifying biomass syngas, including: a) introducing syngas out of a gasifier, through a water-cooling flue to a water-cooling quench tower; b) introducing the syngas from the water-cooling quench tower to a waste heat boiler of a water-tube type and a waste heat boiler of a heat-tube type; c) washing the syngas from the waste heat boiler of the heat-tube type in a Venturi scrubber in the absence of a filler to remove dust; d) introducing the syngas from the Venturi scrubber to a wet electrical dust precipitator for conducting dust removal and tar mist removal; and e) extracting the syngas by a coal gas draft fan, and transporting the syngas to a wet gas tank for storage or to a downstream process for use.

First claim

The invention claimed is:

1. A method for purifying biomass syngas, comprising:
a) introducing syngas out of a gasifier via a top of the gasifier, through a water-cooling flue to a water-cooling quench tower, where water is sprayed into the syngas for quenching slag;
b) introducing the syngas from the water-cooling quench tower to a waste heat boiler of a water-tube type to yield a first vapor and a first cooled syngas having a temperature of 450±20° C.; introducing the first cooled syngas to a waste heat boiler of a heat-tube type to yield a heavy tar, a second vapor, and a second cooled syngas having a temperature of 200±10° C.; and supplying the first vapor and the second vapor to external devices;
c) washing the second cooled syngas in a Venturi scrubber in the absence of a filler to yield a first purified syngas;
d) introducing the first purified syngas from the Venturi scrubber to a wet electrical dust precipitator to yield a second purified syngas for conducting dust removal and tar mist removal; and
e) extracting the second purified syngas by a coal gas draft fan, and transporting the second purified syngas to a wet gas tank for storage or to a downstream process for use.

2. The method of claim 1 , wherein
the syngas produced in the gasifier has a temperature of between 1000 and 1100° C., a dust content of lower than 20 g/Nm 3 , and a tar content of lower than 3 g/Nm 3 ;
the syngas is introduced out of the gasifier via the top of the gasifier, through the water-cooling flue, and into the water-cooling quench tower, where the syngas is cooled to be at 800±20° C.;
the first purified syngas has a temperature of 45±2° C.; and
a flare is in parallel connection with the wet gas tank for combusting waste gas.

3. The method of claim 2 , wherein both the water-cooling flue and the water-cooling quench tower comprise membrane water-cooling pipes.

4. The method of claim 2 , wherein a design pressure in the waste heat boiler of the water-tube type is equal to or larger than 1.6 MPa.

5. The method of claim 2 , wherein the temperature of the second cooled syngas is controlled at less than 200° C. to condense the heavy tar.

6. The method of claim 2 , wherein a design pressure in the waste heat boiler of the heat-tube type is 0.5 MPa, and the second vapor is supplied to the wet electrical dust precipitator.

Assignees

• Wuhan Kaidi General Res Inst Of Eng & Tech Co Ltd
• Wuhan Kaidi Eng Tech Res Inst

Inventors

• Zhang Yanfeng
• Nie Hongtao
• Xia Minggui
• Liu Wenyan
• Zhang Liang

Classifications

• C10K1/02 Primary

  Dust removal · CPC title

• C01B3/506 Primary

  at low temperatures · CPC title

• C10K1/101

  with water only · CPC title

• C01B2203/0465

  Composition of the impurity · CPC title

• Y02P20/129

  Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines · CPC title