WO2012162971A1 - Cyclone bed pulverized coal gasification method and system thereof - Google Patents

Abstract

Provided are a cyclone bed pulverized coal gasification method and a system thereof. The method comprises the following steps: drying and preheating raw coal with the particle size being smaller than or equal to 3 mm in a coal drying and preheating device (2); under the joint action of a mixed gasification agent of oxygen and steam, the dried and preheated raw coal being vertically divided into two and entering a cyclone bed gasifier (6) to undergo a gasification reaction to prepare gasified coal gas; the gasified coal gas entering a coal gas heat exchanger (9) to be further cooled after being chilled at the top of the cyclone bed gasifier (6), and then being purified in a coal gas purification system (11). The system comprises the drying and preheating device (2), the cyclone bed gasifier (6), a chilling gas compressor (8), the coal gas heat exchanger (9), and the coal gas purification system (11). The cyclone bed pulverized coal gasification method and system have the advantages that the structure and process are simple, the manufacturing costs are low, and the coal processing capacity is high.

Description

 Description

 Swirl bed powder coal gasification method and system thereof

 Technical field

 The present invention relates to a method and system for utilizing coal, and more particularly to a method and system for swirling bed coal gasification. Background technique

 In the 21st century, in order to reduce the pollution of coal to the atmosphere, we must vigorously develop clean coal technology. Coal gasification is one of the most important ways to clean and efficiently use coal. It is the most important unit technology for developing modern coal chemical industry. Coal gasification can produce fuel gas, chemical synthetic feed gas, hydrogen fuel cell, coal-gas combined cycle power generation, and synthetic natural gas.

 The existing coal gasification technology is divided into: fixed bed gasification technology, fluidized bed gasification technology and entrained flow gasification technology according to the structural characteristics of the coal gasifier and the movement mode of the fuel in the gasification furnace. Among them, the fixed bed gasification technology can only use lump coal, can not use the end coal or pulverized coal, the maintenance and operation cost of the equipment is high, and the pressurized fixed bed gasification process also produces harmful substances such as phenols and tar, and gas purification treatment. The process is more complicated and easily causes secondary pollution. In the fluidized bed gasification process, a certain amount of carbon must be maintained in the gasifier, and in the fluidized state, the ash is not easily separated from the layer, and the carbon content in the discharged fly ash and ash is higher. High, heat loss is large, and effective fly ash recovery and recycling should be considered. In addition, due to the influence of the gasification temperature, the gasification intensity of the fluidized bed gasifier is limited, the carbon conversion rate is low, and it is not suitable for gasifying coal with strong cohesiveness. The entrained flow gasification technology is divided into wet method (water coal slurry) and dry method according to the feeding method. The equipment and system for wet feeding are single, but because the water used in the pulping process consumes a part of the heat, the carbon conversion rate and gas heat value in coal gasification are lower than that of the dry feed gasifier, and It is suitable for coal with high ash content; the preparation, drying, pressurization and conveying system of coal in dry feeding is complicated, there are many equipments, and the system operation and equipment maintenance cost are expensive. Summary of the invention

The invention provides a spinning bed powder coal gasification method and a system thereof with low manufacturing cost, single process cylinder and large raw coal processing capacity. A method for swirling bed coal gasification that achieves one of the objects of the present invention includes the following steps:

(1) Drying and preheating the raw coal with a particle size less than or equal to 3 mm in a dry preheater; (2) drying and preheating the raw coal under the combined action of oxygen and steam mixed gasification agent Two ways enter the cyclone gasifier, and carry out gasification reaction to prepare gasification gas;

 (3) After the gasification gas is chilled at the top of the cyclone gasifier, it is further cooled by the gas heat exchanger, and then purified in the gas purification system.

 The preheating temperature of the step (1) is 200-300 ° C, and the total moisture after drying is less than or equal to 8%. The gasification reaction of the step (2) is carried out under the conditions of a pressure of ≤ 3.0 MPa and a temperature of 900 to 1500 °C. The chilled gas in the step (3) is pressurized by a chilled gas compressor as part of the purified chilled gas, and then sent to a cyclone gasifier for chilling.

 The water vapor produced by the gas heat exchanger is treated by a high pressure steam boiler and used as a gasification medium together with oxygen produced by the oxygen system.

 A cyclone powder coal gasification system embodying the second object of the present invention, comprising a dry preheater, a cyclone gasifier connected to the dry preheater, connected to the top of the cyclone gasifier a chill gas compressor, a gas heat exchanger connected to a gas outlet of the cyclone gasifier, and a gas purification system connected to a gas outlet of the gas heat exchanger.

 The purified gas outlet of the gas purification system is branched into a passage connected to the inlet of the chiller compressor.

 The water vapor outlet of the gas heat exchanger is connected to a high pressure steam boiler, and the water vapor outlet of the high pressure steam boiler is in communication with the oxygen inlet of the swirling bed gasifier.

 A cyclone dust collector is further disposed between the gas outlet of the cyclone gasifier and the gas heat exchanger. A crusher is arranged at the inlet of the raw material of the dry preheater, and a coal lock bucket and a coal storage bin are arranged in the exit, and an oxygen system is arranged at the oxygen inlet of the cyclone gasification furnace.

 The cyclone bed coal gasification method and system thereof of the invention have the advantages of a fluidized bed gasification furnace and an entrained flow gasification furnace by using a cyclone bed as a gasification furnace, and the equipment structure is simple, and the manufacturing cost is low. The raw material processing capacity is large and easy to operate. DRAWINGS

Figure 1 is a schematic view showing the structure of a swirling bed powder coal gasification system of the present invention. detailed description

 The invention will be described in more detail below with reference to the accompanying drawings.

 The cyclone powder coal gasification system of the present invention comprises a dry preheater, a cyclone gasifier connected to the dry preheater, and a chill gas compressor connected to the top of the cyclone gasifier, a gas heat exchanger connected to the gas outlet of the cyclone gasifier, and a gas purification system connected to the gas outlet of the gas heat exchanger.

 Specifically, as shown in FIG. 1, the swirling bed powder coal gasification system of the present invention comprises a crusher 1, a dry preheater 2, a coal lock bucket 3, a coal bunker 4 and a cyclone gasifier 6, in turn Connected; the oxygen inlet of the cyclone gasifier 6 is provided with an oxygen system 5, a chill gas compressor 8 connected to the top of the cyclone gasifier 6, and a gas outlet of the cyclone gasifier 6 a connected cyclone 7, a gas heat exchanger 9 connected to the cyclone 7, a gas purification system 11 connected to the gas outlet of the gas heat exchanger 9, and a purified gas outlet of the gas purification system 11 The air inlet of the cold air compressor 8 is connected; the water vapor outlet of the gas heat exchanger 9 is connected to a high pressure steam boiler 10, and the water vapor outlet of the high pressure steam boiler 10 is connected to the oxygen inlet of the cyclone gasification furnace 6.

 The method for swirling bed powder coal gasification of the present invention is as follows:

 Example 1

 Taking the production scale of coal treatment capacity 2t/h as an example, the coal quality analysis of raw coal is shown in Table 1. As shown in Fig. 1, the raw coal is crushed by the crusher 1 into a particle size of ≤ 1 mm, and then dried in the dry preheater 2 to a total moisture of 8%, and the temperature after preheating is 250 ° C; after drying and preheating The coal powder passes through the coal lock bucket 3 and the coal-filling silo 4 in turn, and the oxygen from the oxygen-making system 5 and the steam of the high-pressure steam boiler 10 act together to enter the cyclone gasification furnace 6 under pressure, at a pressure of l. Gasification is carried out by gasification reaction at OMPa and temperature of 1000 °C; the produced high-temperature gas is chilled in the upper part of the cyclone gasifier 6, the chill gas is from the chiller compressor 8; the chilled gas is swirled from the vortex The top of the bed gasifier 6 enters the cyclone dust collector 7 to remove dust, and the clean gas enters the gas heat exchanger 9 for further cooling, and then is purified in the gas purification system 11, and a part of the purified gas is pressurized by the chilling gas compressor 8 as chilling gas. The water vapor produced by the gas heat exchanger 9 is treated by the high pressure steam boiler 10 and used together with the oxygen produced by the oxygen generation system 5 as a gasification medium. The gas gas components after purification are shown in Table 2.

表 2 煤气的气体组 Table 1 Coal quality analysis results of raw coal (%)

Table 2 Gas group of gas

实施例 2

Example 2

 Taking the production scale of coal treatment capacity 2t/h as an example, the coal quality analysis of raw coal is shown in Table 3. As shown in Fig. 1, the raw coal is crushed by the crusher 1 into a particle size of ≤ 3 mm, and then dried in the dry preheater 2 to a total moisture of 8%, and the temperature after preheating is 200 ° C; after drying and preheating The coal powder passes through the coal lock bucket 3 and the coal loading bin 4 in turn, and the oxygen from the oxygen system 5 and the steam of the high-pressure steam boiler 10 act together to enter the cyclone gasifier 6 at a pressure of 3.0 MPa. Gasification is carried out by gasification reaction at a temperature of 900 °C; the produced high-temperature gas is chilled in the upper part of the cyclone gasifier 6, the chill gas is from the chiller compressor 8; the chilled gas is from the cyclone bed The top of the gasification furnace 6 enters the cyclone dust collector 7 to remove dust, and the clean gas enters the gas heat exchanger 9 for further cooling, and then is purified in the gas purification system 11, and a part of the purified gas is pressurized by the chilling gas compressor 8 and used as chilling gas. The water vapor produced by the gas heat exchanger 9 is treated by the high pressure steam boiler 10 and used together with the oxygen produced by the oxygen generation system 5 as a gasification medium. The gas gas components after purification are shown in Table 4.

表 4 煤气的气体组 Table 3 Results of coal quality analysis of raw coal (%)

Table 4 Gas group of gas

实施例 3

Example 3

 Taking the production scale of coal treatment capacity 2t/h as an example, the coal quality analysis of raw coal is shown in Table 5. As shown in Fig. 1, the raw coal is crushed by the crusher 1 into a particle size of ≤ 3 mm, and then dried in the dry preheater 2 to a total moisture of 8%, and the temperature after preheating is 300 ° C; after drying and preheating The coal powder passes through the coal lock bucket 3 and the coal-filling silo 4 in turn, and the oxygen from the oxygen-making system 5 and the steam of the high-pressure steam boiler 10 act together to enter the cyclone gasification furnace 6 under pressure, at a pressure of l. Gasification is carried out by gasification reaction at OMPa and temperature of 1500 °C; the produced high-temperature gas is chilled in the upper part of the cyclone gasifier 6, the chill gas is from the chiller compressor 8; the chilled gas is swirled from the vortex The top of the bed gasifier 6 enters the cyclone dust collector 7 to remove dust, and the clean gas enters the gas heat exchanger 9 for further cooling, and then is purified in the gas purification system 11, and a part of the purified gas is pressurized by the chilling gas compressor 8 as chilling gas. The water vapor produced by the gas heat exchanger 9 is treated by the high pressure steam boiler 10 and used together with the oxygen produced by the oxygen generation system 5 as a gasification medium. The gas gas components after purification are shown in Table 6.

Table 5 Coal quality analysis results of raw coal (%)

Table 6 gas group of gas

Claims

Claim  1. A method for swirling bed coal gasification, comprising the steps of:  (1) Drying and preheating the raw coal with a particle size less than or equal to 3 mm in a dry preheater; (2) drying and preheating the raw coal under the combined action of oxygen and steam mixed gasification agent Two ways enter the cyclone gasifier, and carry out gasification reaction to prepare gasification gas;  (3) After the gasification gas is chilled at the top of the cyclone gasifier, it is further cooled by the gas heat exchanger, and then purified in the gas purification system.  2. The method of swirling bed coal gasification according to claim 1, wherein: said step (1) The preheating temperature is 200-300 ° C, and the total moisture after drying is less than or equal to 8%.  3. The method of swirling bed powder coal gasification according to claim 1, wherein: said step The gasification reaction of (2) is carried out under the conditions of pressure ≤ 3.0 MPa and temperature of 900-1500 °C.  4. The method of swirling bed powder coal gasification according to claim 1, wherein: said step The chilled gas in (3) is pressurized by a chilled gas compressor for a part of the purified gas, and then sent to a cyclone gasifier for chilling.  The method according to claim 1, wherein the water vapor produced by the gas heat exchanger is treated by a high pressure steam boiler together with oxygen produced by the oxygen system as a gasification medium. use.  6. A swirling bed powder coal gasification system, comprising: a drying preheater, a cyclone gasifier connected to the drying preheater, and a chilling gas compression connected to a top of the cyclone gasifier And a gas heat exchanger connected to the gas outlet of the cyclone gasifier, and a gas purification system connected to the gas outlet of the gas heat exchanger.  7. The cyclone bed coal gasification system according to claim 6, wherein: the purified gas outlet of the gas purification system is separated from a gas passage of the chill gas compressor by a passage.  The cyclone bed coal gasification system according to claim 6, wherein a cyclone dust collector is further disposed between the gas outlet of the cyclone gasifier and the gas heat exchanger.  9. The cyclone bed coal gasification system according to claim 6, wherein: the raw material inlet of the dry preheater is provided with a crusher, and the outlet is provided with a coal lock bucket and a coal storage bin in turn. An oxygen system is provided at the oxygen inlet of the cyclone gasifier. 10. The swirling bed powder coal gasification system according to claim 6, wherein: said gas The water vapor outlet of the heat exchanger is connected to a high pressure steam boiler, and the water vapor outlet of the high pressure steam boiler is in communication with the oxygen inlet of the swirling bed gasifier.