Process for fixed bed coal gasification

• US 5,145,490 A
• Filed: 12/26/1991
• Issued: 09/08/1992
• Est. Priority Date: 08/09/1990
• Status: Expired due to Fees

• Current Assignee: Riley Stoker Corporation (Babcock Power Incorporated)
• Original Assignee: CRS Sirrine Engineers, Inc.
• Inventors: Sadowski, Richard S.
• Primary Examiner(s): KRATZ, PETER F
• Application Number:
  US07/814,102
• Time in Patent Office: 257 Days
• Field of Search: 48/63, 48/64, 48/76, 48/77, 48/68, 48/66, 48/DIG. 4, 48/203, 48/206, 48/67, 48/69, 48/62 R, 48/87, 48/197 R, 48/209, 48/210
• US Class Current: 48/197.00R
• CPC Class Codes: C10J 2300/093 Coal
• CPC Class Codes: C10J 2300/0956 Air or oxygen enriched air
• CPC Class Codes: C10J 2300/0976 as steam
• CPC Class Codes: C10J 3/20 Apparatus; Plants
• CPC Class Codes: C10J 3/42 Rotary grates
• CPC Class Codes: C10J 3/485 Entrained flow gasifiers
• CPC Class Codes: C10J 3/58 combined with pre-distillation of the fuel
• CPC Class Codes: C10J 3/66 by introducing them into the gasification zone
• CPC Class Codes: C10J 3/721 Multistage gasification, e.g. plural parallel or serial gasification stages
• CPC Class Codes: C10K 3/008 by cracking

Abstract

The combustion of gas produced from the combination of coal pyrolysis and gasification involves combining a combustible gas coal and an oxidant in a pyrolysis chamber and heating the components to a temperature of at least 1600° F. The products of coal pyrolysis are dispersed from the pyrolyzer directly into the high temperature gasification region of a pressure vessel. Steam and air needed for gasification are introduced in the pressure vessel and the materials exiting the pyrolyzer flow down through the pressure vessel by gravity with sufficient residence time to allow any carbon to form carbon monoxide. Gas produced from these reactions are then released from the pressure vessel and ash is disposed of.

Claims

1. A method of gasifying solid carbonaceous fuel, comprising the steps of:

(a) introducing solid carbonaceous fuel, an oxidant, and a combustible gas under pressure into a first end of an open-ended entrained bed pyrolyzer tube, said tube housed within a fixed bed pressure vessel with the tube extending through the fixed bed;

(b) igniting the combustible gas in order to devolatilize the fuel within the pyrolyzer tube and form ash, char, and volatiles;

(c) discharging the devolatilized fuel comprising char, ash, and volatiles from a second end of the pyrolyzer tube directly into the pressure vessel at a location above the fixed bed and passing the char, ash, and volatiles downwardly through a high temperature region of the fixed bed pressure vessel;

(d) introducing gasifying agents into the pressure vessel at a point adjacent to the second end of the pyrolyzer tube to crack any tar present;

(e) allowing said pressure vessel to heat to a temperature sufficient to oxidize the ash and char to carbonaceous gases, the ash and char descending by gravity;

(f) allowing unreacted char and ash to cool;

(g) removing ash, char, and volatiles from the pressure vessel.

2. A method of gasifying coal, comprising the steps of:

(a) introducing coal, a combustible gas, and oxidant into one end of an open-ended entrained-bed pyrolyzer tube housed within a fixed bed coal gasifier, with the tube extending through the fixed bed;

(b) igniting the combustible gas to about 1600°

F. in order to devolatilize the coal;

(c) discharging devolatilized coal, gaseous volatiles and char from the other end of the pyrolyzer tube directly into the fixed-bed coal gasifier at a location above the fixed bed;

(d) introducing gasifying agents into the fixed bed-coal gasifier near the pyrolyzer other and in order to crack tar and asphalt fractions of coal;

(e) conveying char, ash, and unreacted coal by gravity feed into a heated zone of the fixed bed gasifier and passing the gaseous volatiles therewith through the heated zone of the gasifier;

(f) allowing the gasifier to heat to about 1900°

F. in order to produce carbonaceous gases from the char, ash, and unreacted coal;

(g) removing gases from the gasifier;

(h) allowing ash to cool and to become deposited on a rotating grate;

(i) rotating the grate to remove ash, and char from the gasifier.