Method for using fast fluidized bed dry bottom coal gasification
First Claim
1. A process for gasifying particulate hydrocarbon feed materials to produce a fuel gas product, having low-to-medium heating value, comprising:
- (a) introducing the hydrocarbon feed material with steam and oxygen into a gasification zone containing a fast fluidized bed of char particles for gasification therein, said zone being maintained at temperature of 1500°
-1850°
F., at pressure exceeding about 30 psig, and at upward superficial gas velocity exceeding about 5 ft/sec to heat and gasify the feed and produce a gaseous material;
(b) withdrawing said gaseous material along with char particles from the upper portion of the gasification zone and passing the materials to a primary gas-solids separation step for char solids removal;
(c) withdrawing a first gas stream from said primary gas-solids separation step and returning particulate char solids to the gasification zone;
(d) passing said first gas stream to a secondary gas-solids separation step and removing fine char solids therefrom;
(e) returning the fine particulate char solids from the secondary gas-solids separation step to the lower end of a fluidized bed oxidation zone located immediately below the fast fluidized bed gasification zone;
said oxidation zone having temperature maintained within the range of 1600°
-2000°
F.; and
(f) withdrawing a fuel gas product stream from the secondary gas-solids separation step.
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Accused Products
Abstract
Carbonaceous solid material such as coal is gasified in a fast fluidized bed gasification system utilizing dual fluidized beds of hot char. The coal in particulate form is introduced along with oxygen-containing gas and steam into the fast fluidized bed gasification zone of a gasifier assembly wherein the upward superficial gas velocity exceeds about 5.0 ft/sec and temperature is 1500°-1850° F. The resulting effluent gas and substantial char are passed through a primary cyclone separator, from which char solids are returned to the fluidized bed. Gas from the primary cyclone separator is passed to a secondary cyclone separator, from which remaining fine char solids are returned through an injection nozzle together with additional steam and oxygen-containing gas to an oxidation zone located at the bottom of the gasifier, wherein the upward gas velocity ranges from about 3-15 ft/sec and is maintained at 1600°-200° F. temperature. This gasification arrangement provides for increased utilization of the secondary char material to produce higher overall carbon conversion and product yields in the process.
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Citations
11 Claims
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1. A process for gasifying particulate hydrocarbon feed materials to produce a fuel gas product, having low-to-medium heating value, comprising:
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(a) introducing the hydrocarbon feed material with steam and oxygen into a gasification zone containing a fast fluidized bed of char particles for gasification therein, said zone being maintained at temperature of 1500°
-1850°
F., at pressure exceeding about 30 psig, and at upward superficial gas velocity exceeding about 5 ft/sec to heat and gasify the feed and produce a gaseous material;(b) withdrawing said gaseous material along with char particles from the upper portion of the gasification zone and passing the materials to a primary gas-solids separation step for char solids removal; (c) withdrawing a first gas stream from said primary gas-solids separation step and returning particulate char solids to the gasification zone; (d) passing said first gas stream to a secondary gas-solids separation step and removing fine char solids therefrom; (e) returning the fine particulate char solids from the secondary gas-solids separation step to the lower end of a fluidized bed oxidation zone located immediately below the fast fluidized bed gasification zone;
said oxidation zone having temperature maintained within the range of 1600°
-2000°
F.; and(f) withdrawing a fuel gas product stream from the secondary gas-solids separation step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A process for gasifying coal to produce a fuel gas product, having low-to-medium heating value, comprising:
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(a) introducing coal feed into a gasification zone containing a fast fluidized bed of char particles for gasification therein, said zone being maintained at 1500°
-1850°
F. temperature range, at pressure exceeding about 30 psig and at upward superficial gas velocity exceeding about 5 ft/sec, and a weight ratio of char to coal feed maintained between about 20 to 30 to heat and gasify the coal and produce a gaseous material;(b) withdrawing said gas and substantial char from the upper portion of the fast fluidized bed gasification zone and passing the materials to a primary gas-solids separation step for char solids removal; (c) withdrawing a first gas stream from said primary solids separation step and returning particulate char solids to the gasification zone; (d) passing said first gas stream to a secondary gas-solids separation step and removing a fine char solids therefrom; (e) returning the fine particulate char solids from the secondary gas-solids separation step through a gas shrouded nozzle into the lower end of a fluidized bed oxidation zone maintained at temperature within the range of 1600°
-2000°
F. and located immediately below the fast fluidized bed gasification zone; and(f) withdrawing a fuel gas product stream from the secondary gas-solids separation step. - View Dependent Claims (11)
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Specification