CN107937035B - Pulverized coal pressurized gasification device and method with two sections of double-circulation fluidized bed coupled - Google Patents

Abstract

A pulverized coal pressurized gasification device and method of two-section coupling of a double-circulation fluidized bed belong to the technical field of coal gasification, and are characterized in that: comprises a first-stage reactor and a second-stage reactor; the primary reactor comprises a reaction system, a carbonaceous material recovery system and a return conveying system which are connected end to end; the secondary reactor comprises a secondary reaction system, a fine ash collecting device and a return conveying system which are connected end to end; the first-stage reactor is connected with the second-stage reactor through a pipeline. The improved device has high solid circulation rate and gas speed, high device processing capacity, sufficient heat exchange of reaction medium, high heat exchange efficiency and small integral temperature difference of the circulating fluidized bed; the coal variety application range is wide, and the low-rank coal is expanded to medium-rank and high-rank coal with rich reserves in China; the content of effective gas components in the gas and the conversion rate of carbon are improved, and the generated synthesis gas does not contain any tar, so that the subsequent gas purification is relatively simple.

Description

A double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device and method

Technical field

The invention belongs to the technical field of coal gasification, and in particular relates to a two-stage coupling pulverized coal pressurized gasification device and method of a double circulating fluidized bed.

Background technique

China's resource endowment is more coal than oil and gas. Coal has played an important role in my country's economic development, but its extensive use has also produced many negative impacts. Coal gasification, as an important technology for coal conversion and utilization, has received more and more attention. However, the existing coal chemical technology has limited applicability of coal types and cannot better solve the problems of large-scale, clean and efficient. At present, there are relatively large reserves of mid- and high-rank coals in China. How can gasification technology that is only suitable for low-rank coals solve the problems encountered in mid- and high-rank coals such as low carbon conversion rate, high methane content in syngas and coal tar? defects, and increasing processing throughput and reducing energy consumption have become key issues.

The circulating fluidized bed reactor has good adaptability to low-denatured lignite with high volatile matter, large specific surface area, and good activity. However, for the gasification of other coal ranks in China, it has high tar, methane and dust particle contents. Fatal defects such as low carbon conversion rate limit the wide-scale promotion and application of circulating fluidized beds.

Contents of the invention

The purpose of the present invention is to provide a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device, which improves the applicable scope of coal types and is suitable for lignite and low-deterioration bituminous coal, which account for 55% of my country's total coal. Large quantity, high heat transfer efficiency, high carbon conversion rate, high content of effective gas components in the obtained synthesis gas, low content of tar and methane, and no black water production.

The present invention describes a dual-circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device, which includes a first-stage reactor and a second-stage reactor; the first-stage reactor includes a reaction system connected end-to-end, a carbon-containing Material recovery system and return material transportation system; the two-stage reactor includes a secondary reaction system connected end-to-end, a fine ash collection device and a return material transportation system; the first-stage reactor and the second-stage reactor are connected through pipelines.

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The reaction system includes a riser; the lower end of the riser is provided with a pulverized coal feed inlet and a main gasification device in sequence. agent inlet, fluidizing gas control device, flue gas preheating inlet and ash discharge port; the carbonaceous material recovery system includes a secondary cyclone separator, a primary cyclone separator and a circulating sealed tank connected in sequence; the primary stage The lower end of the cyclone separator is equipped with a loose air control device;

The return material conveying system includes a standpipe; a standpipe material level monitoring device is connected to the side wall of the standpipe; a parking discharge port is provided at the lower end of the standpipe; and a parking discharge port is provided at the upper end of the circulating sealed tank. Bed material adding device;

The upper end of the riser is connected to the first-level cyclone separator, and the lower end is connected to the standpipe through the return leg; the circulation sealing tank is connected to the standpipe; a return material is provided between the standpipe and the return leg. Delivery gas control device.

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The secondary reaction system includes a reaction zone, an auxiliary gasification agent inlet and a speed increasing zone arranged in sequence; The material conveying system includes a bed material replenishing device, a vertical material leg and a return material circulation sealed tank arranged in sequence; a vertical material leg material level monitoring device is provided on one side of the vertical material leg; the vertical material A return material conveying air control device is provided between the legs and the return material circulation sealed tank.

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The flue gas preheating inlet is located below the connection between the return leg and the riser to facilitate the circulation of sand in the return leg. Carry out sufficient preheating and fluidization.

In the double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device of the present invention, the main gasification agent inlet includes three areas, and each area includes a number of evenly arranged branches and are connected with each other. The riser pipe is connected to avoid uneven distribution of gasifying agent and local overoxygen.

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The secondary cyclone separator is connected to the speed-increasing zone through a pipe lined with refractory castables.

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The fillers used in the bed material adding device and the bed material filling device are coal ash, quartz sand and sand. One or more, particle size range 80-160μm.

The present invention is a dual circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The inner walls of the first-stage reactor and the second-stage reactor are provided with refractory and insulated lining layers to reduce heat loss.

The double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification method of the present invention includes the following steps:

(1) Establishment of loose gas: Establish loose gas in the first-stage reactor and second-stage reactor through the fluidizing gas control device, loose gas control device, return material conveying gas control device and return material conveying gas control device respectively, and control the loose air volume. Ensure that the gas flow rate of each loose gas nozzle is 1.2-1.5m/s;

(2) Establishment of bed material level: Solid materials are added to the first-stage reactor and the second-stage reactor through the bed material adding device and the bed material replenishing device respectively. Through the loosening of loose gas and the action of the material's own gravity, the material is moved from The riser pipe and vertical material legs flow into the riser pipe and speed increasing zone;

(3) Establishment of cold-state circulating fluidization: Add fluidizing gas to the first-stage reactor through the fluidizing gas control device, and control the gas velocity in the standpipe to 4-8m/s;

(4) Reaction device preheating: The first-stage reactor is provided with heat-carrying flue gas through the flue gas preheating inlet, and the circulating fluidized solid material exchanges heat with it to heat the entire reactor device. The second-stage reactor passes through the second-stage reactor The flue gas at the outlet of the cyclone separator is preheated, and the temperature of the first-stage reactor device is raised to about 980°C;

(5) Feeding reaction: Transport pulverized coal to the first-stage reactor through the pulverized coal feed inlet, mix it with a ratio of steam/oxygen in the range of 0.93-1.42 (kg/Nm ³ ), and then enter the reaction system through the main gasification agent inlet. , an oxidation-reduction reaction occurs with pulverized coal, converting the carbon in pulverized coal into crude synthesis gas mainly containing hydrogen and carbon monoxide;

(6) Gasification agent replenishment in the second-stage reactor: Steam/oxygen is mixed in a ratio of 0.6-1.5 (kg/ ^Nm3 ) through the auxiliary gasification agent inlet and enters the speed-increasing zone, and is mixed with the gasification agent from the outlet of the first-stage reactor. The crude syngas is rapidly mixed, and the gasification agent supplemented in the reaction zone performs a secondary gasification reaction with the unreacted carbon residue, tar and methane components carried in the crude syngas. The temperature control of the second-stage reactor device At 1050-1100℃.

In the double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification method of the present invention, the raw material of the pulverized coal in step (5) is lignite, bituminous coal or anthracite; any one of them is selected as the raw material to effectively expand the The scope of application of coal types.

The beneficial effects of the double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device and method described in the present invention are:

(1) The solid circulation rate and gas velocity are fast, the device processing capacity is large, the reaction medium has sufficient heat exchange, the heat exchange efficiency is high, and the overall temperature difference of the circulating fluidized bed is small;

(2) Coal types have a wide adaptability range, extending from low-rank coal to mid- and high-rank coal with abundant reserves in China;

(3) The coupling technology of the two-stage reactor increases the reaction temperature, deeply cracks the tar and residual carbon in the crude gas, increases the content of effective gas components and the carbon conversion rate in the gas, and the generated synthesis gas does not contain any tar, making subsequent gas purification relatively simple;

(4) Since the entire gasification reaction process adopts the pneumatic conveying and feeding method of dry pulverized coal, and the ash discharge adopts the method of high-temperature ash cooling and continuous decompression solid state discharge, there is no discharge of waste water in the entire reaction process, completely eliminating black water. The generation of water effectively reduces the water consumption of the device;

(5) The first and second stage reactor equipment has a simple structure and no internal parts, moving parts and expansion joints, which effectively saves equipment investment costs and requires no additional slag treatment and removal equipment.

Description of the drawings

Figure 1 is a schematic flow diagram of a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device provided by the present invention;

Among them: A-first-stage reactor, B-second-stage reactor, 1-reaction system, 2-carbonaceous material recovery system, 3-return material transportation system, 4-secondary reaction system, 5-fine ash collection device, 6-Return material conveying system, 7-Pipeline, 11-Pulverized coal feed inlet, 12-Main gasification agent inlet, 13-Fluidizing gas control device, 14-Rising pipe, 15-Ash discharge port, 16-Fume gas Preheating inlet, 21-first-level cyclone separator, 22-secondary cyclone separator, 23-circulation sealed tank, 24-loose air control device, 31-standpipe, 32-standpipe material level monitoring device, 33-return Material conveying gas control device, 34-bed material adding device, 35 return leg, 36-stop discharge port, 41-speed increase zone, 42-reaction zone, 43-auxiliary gasification agent inlet, 61-vertical material Leg, 62 vertical material leg material level monitoring device, 63-bed material replenishing device, 64-return material circulation sealed tank, 65-return material conveying air control device.

Detailed ways

The pressurized gasification device and method of pulverized coal with dual circulating fluidized bed and two-stage coupling according to the present invention will be described in detail below with reference to the accompanying drawings and examples.

A dual circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device according to the present invention, as shown in Figure 1, includes two parts: a first-stage reactor (A) and a second-stage reactor (B); The first-stage reactor (A) includes a reaction system (1) connected end-to-end, a carbonaceous material recovery system (2) and a return material transportation system (3); the second-stage reactor (B) includes a secondary reaction system connected end-to-end. (4), fine ash collection device (5) and return material transportation system (6); the first-stage reactor (A) and the second-stage reactor (B) are connected through a pipeline (7).

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The reaction system (1) includes a riser (14); the lower end of the riser (14) is sequentially provided with Pulverized coal feed inlet (11), main gasification agent inlet (12), fluidizing gas control device (13), flue gas preheating inlet (16) and ash discharge port (15); the carbonaceous material recovery system (2) It includes a secondary cyclone separator (22), a primary cyclone separator (21) and a circulating sealed tank (23) connected in sequence; a loose air control device is provided at the lower end of the primary cyclone separator (21) (24); the return material conveying system (3) includes a standpipe (31); a standpipe material level monitoring device (32) is connected to the side wall of the standpipe (31); the standpipe (31) ) is provided with a parking discharge port (36) at its lower end; the upper end of the circulating sealed tank is provided with a bed material adding device (34); the upper end of the riser (14) is in contact with the first-level cyclone separator (21) connection, the lower end is connected to the standpipe (31) through the return leg (35); the circulation sealing tank (23) is connected to the standpipe (31); the standpipe (31) is connected to the return leg (35) A return material conveying gas control device (33) is provided in the room. The secondary reaction system (4) includes a reaction zone (42), an auxiliary gasification agent inlet (43) and a speed increasing zone (41) arranged in sequence; the return material transportation system (6) includes a bed layer arranged in sequence Material replenishing device (63), vertical material leg (61) and return material circulation sealed tank (64); a vertical material leg material level monitoring device (62) is provided on one side of the vertical material leg (61) ; A return material conveying air control device (65) is provided between the vertical material leg (61) and the return material circulation sealed tank (64).

In a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device according to the present invention, the flue gas preheating inlet (16) is located below the connection between the return leg (35) and the riser pipe (14) .

In the double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device of the present invention, the main gasification agent inlet (12) includes three areas, in which the upper area includes 6 branches, and the middle area The area includes 18 branches, the lower area includes 1 branch, and each branch is connected to the riser (14).

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The secondary cyclone separator (22) passes through a pipe (7) lined with refractory castable material and a speed increasing zone ( 41) connected.

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The filler used in the bed material adding device (34) and the bed material filling device (63) is coal ash. One or more of quartz sand and sand, with a particle size range of 80-160 μm.

The present invention is a dual circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device. The inner walls of the first-stage reactor (A) and the second-stage reactor (B) are both equipped with refractory and insulating lining layers.

The present invention is a double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification method. The raw material of pulverized coal is anthracite; it includes the following steps:

(1) Loose gas establishment: Through the fluidizing gas control device (13), loose gas control device (24), return material conveying gas control device (33) and return material conveying gas control device (65), the reactor ( A), the second-stage reactor (B) establishes loose gas, controls the loose gas volume, and ensures that the gas flow rate of each loose gas nozzle is 1.2-1.5m/s;

(2) Bed material level establishment: Add solid materials to the first-stage reactor (A) and the second-stage reactor (B) through the bed material adding device (34) and the bed material replenishing device (63) respectively. The loose air and the material's own gravity cause the material to flow from the riser (31) and the vertical material leg (61) into the riser tube (14) and the speed increasing zone (41);

(3) Establishment of cold circulating fluidization: add fluidizing gas into the first-stage reactor (A) through the fluidizing gas control device (13), and control the gas velocity in the standpipe (31) at 4-8m/s;

(4) Preheating of the reaction device: Provide heat-carrying flue gas to the reactor (A) through the flue gas preheating inlet (16), and exchange heat with the circulating fluidized solid material to heat the entire reactor device. The section reactor (B) is preheated by the flue gas at the outlet of the secondary cyclone separator (22), and the temperature of the section reactor (A) is raised to about 980°C;

(5) Feeding reaction: Transport pulverized coal to the first-stage reactor (A) through the pulverized coal feed inlet (11), mix it with a ratio of steam/oxygen in the range of 0.93-1.42 (kg/Nm ³ ), and then pass through the main gas The chemical agent inlet (12) enters the reaction system (1), undergoes an oxidation-reduction reaction with the pulverized coal, and converts the carbon in the pulverized coal into crude synthesis gas mainly containing hydrogen and carbon monoxide;

(6) Second-stage reactor gasification agent replenishment: steam/oxygen is mixed in a ratio ranging from 0.6 to 1.5 (kg/Nm ³ ) and then enters the speed increasing zone (41) through the auxiliary gasification agent inlet (43), and The crude syngas from the outlet of the first-stage reactor (A) is rapidly mixed, and the gasification agent supplemented in the reaction zone (42) is mixed with the unreacted carbon residue, tar and methane components carried in the crude syngas for a second time. For the gasification reaction, the temperature of the second-stage reactor (B) device is controlled at 1050-1100°C.

Claims (7)

1. A double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device, characterized in that: it includes a first-stage reactor (A) and a second-stage reactor (B); the first-stage reactor (A) ) includes a reaction system (1) connected end-to-end, a carbonaceous material recovery system (2) and a return material conveying system (3); the two-stage reactor (B) includes a secondary reaction system (4) connected end-to-end, Ash capture device (5) and return material transportation system (6); the first-stage reactor (A) and the second-stage reactor (B) are connected through a pipeline (7); The reaction system (1) includes a riser (14); the lower end of the riser (14) is provided with a pulverized coal feed inlet (11), a main gasification agent inlet (12), and a fluidizing gas control device (12). 13), flue gas preheating inlet (16) and ash discharge port (15); the carbonaceous material recovery system (2) includes a secondary cyclone separator (22) and a primary cyclone separator (21) connected in sequence and a circulating sealed tank (23); a loose air control device (24) is provided at the lower end of the first-stage cyclone separator (21); The return material conveying system (3) includes a riser (31); a riser material level monitoring device (32) is connected to the side wall of the riser (31); the lower end of the riser (31) is provided with There is a parking discharge port (36); the upper end of the circulating sealed tank is provided with a bed material adding device (34); The upper end of the riser pipe (14) is connected to the first-level cyclone separator (21), and the lower end is connected to the standpipe (31) through the return leg (35); the circulation sealing tank (23) is connected to the standpipe (31). 31) are connected; a return material conveying air control device (33) is provided between the riser (31) and the material return leg (35); The secondary reaction system (4) includes a reaction zone (42), an auxiliary gasification agent inlet (43) and a speed increasing zone (41) arranged in sequence; the return material transportation system (6) includes a bed layer arranged in sequence Material replenishing device (63), vertical material leg (61) and return material circulation sealed tank (64); a vertical material leg material level monitoring device (62) is provided on one side of the vertical material leg (61) ;A return material conveying air control device (65) is provided between the vertical material leg (61) and the return material circulation sealed tank (64); According to the gasification method of the double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device, the gasification method includes the following steps: (1) Loose gas establishment: Through the fluidizing gas control device (13), loose gas control device (24), return material conveying gas control device (33) and return material conveying gas control device (65), the reactor ( A), the second-stage reactor (B) establishes loose gas, controls the loose gas volume, and ensures that the gas flow rate of each loose gas nozzle is 1.2-1.5m/s; (2) Bed material level establishment: Add solid materials to the first-stage reactor (A) and the second-stage reactor (B) through the bed material adding device (34) and the bed material replenishing device (63) respectively. The loose air and the material's own gravity cause the material to flow from the riser (31) and the vertical material leg (61) into the riser tube (14) and the speed increasing zone (41); (3) Establishment of cold circulating fluidization: add fluidizing gas into the first-stage reactor (A) through the fluidizing gas control device (13), and control the gas velocity in the standpipe (31) at 4-8m/s; (4) Preheating of the reaction device: Provide heat-carrying flue gas to the reactor (A) through the flue gas preheating inlet (16), and exchange heat with the circulating fluidized solid material to heat the entire reactor device. The section reactor (B) is preheated by the flue gas at the outlet of the secondary cyclone separator (22), and the device temperature of the section reactor (A) is raised to 980°C; (5) Feeding reaction: Transport pulverized coal to the first-stage reactor (A) through the pulverized coal feed inlet (11), mix it with a ratio of steam/oxygen in the range of 0.93-1.42 (kg/Nm ³ ), and then pass through the main gas The chemical agent inlet (12) enters the reaction system (1), undergoes an oxidation-reduction reaction with the pulverized coal, and converts the carbon in the pulverized coal into crude synthesis gas mainly containing hydrogen and carbon monoxide; (6) Second-stage reactor gasification agent replenishment: steam/oxygen is mixed in a ratio ranging from 0.6 to 1.5 (kg/Nm ³ ) and then enters the speed increasing zone (41) through the auxiliary gasification agent inlet (43), and The crude syngas from the outlet of the first-stage reactor (A) is rapidly mixed, and the gasification agent supplemented in the reaction zone (42) is mixed with the unreacted carbon residue, tar and methane components carried in the crude syngas for a second time. For the gasification reaction, the temperature of the second-stage reactor (B) device is controlled at 1050-1100°C. 2. A double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device according to claim 1, characterized in that: the flue gas preheating inlet (16) is located between the return leg (35) and Below the connection port of the riser pipe (14). 3. A dual circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device according to claim 2, characterized in that: the main gasification agent inlet (12) includes three areas, each area It includes several evenly arranged branches and are all connected with the riser pipe (14). 4. A dual-circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device according to claim 1 or 3, characterized in that: the secondary cyclone separator (22) passes through a refractory castable lining. The pipeline (7) is connected to the speed increase zone (41). 5. A double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device according to claim 4, characterized in that: the bed material adding device (34), the bed material adding device (34), 63) The filler used is one or more of coal ash, quartz sand and sand, with a particle size range of 80-160 μm. 6. A dual circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device according to claim 5, characterized in that: the inner walls of the first-stage reactor (A) and the second-stage reactor (B) All are equipped with fire-resistant insulating lining. 7. A double circulating fluidized bed two-stage coupled pulverized coal pressurized gasification device according to claim 6, characterized in that: the raw material of the pulverized coal in step (5) is lignite, bituminous coal or anthracite.