A method for controlling feeding of a pulverized coal gasifier

Abstract

The application discloses a feeding control method of a pulverized coal gasifier. In the initial feeding stage of the pulverized coal gasifier, the pressure difference between a pulverized coal feeding tank and the pulverized coal gasifier is set to 1.0-3.5 MpaG, which is much higher than the normal feeding pressure difference of 0.8-1.0 MpaG. The feeding is performed by using the high pressure difference, so that the conveying state of the pulverized coal is changed from the turbulent flow state under the low pressure difference to the plug flow state under the high pressure difference, thereby improving the stability of the dense phase conveying of the pulverized coal. After the pulverized coal is transferred from the circulating line of the coal line to the normal feeding process, the density and speed of the pulverized coal can be continuously stable, and the fluctuation is greatly reduced, so that the non-disturbance switching of the circulating line of the coal line and the feeding process is realized. Meanwhile, the stability of the coal line flow during the continuous pressure increasing process of the pulverized coal gasifier after feeding is ensured.

Description

Technical Field

[0001] This invention relates to the field of pressurized coal gasification technology, specifically a method for controlling the feeding of a pulverized coal gasifier. Background Technology

[0002] Gasification is a thermochemical process involving carbonaceous materials. Gasification technology typically uses pulverized carbonaceous solid fuels such as coal or their mixed liquid fuels as raw materials, and gaseous substances containing oxygen and water vapor as gasifying agents. After being injected into a pulverized coal gasifier through burners, a gasification reaction occurs under high temperature and high pressure conditions, producing high-temperature and high-pressure syngas (or coal gas) and slag.

[0003] Pulverized coal gasifiers are typically equipped with a pressurized pulverized coal conveying system and a coal conveying line system. Under normal operating conditions, pulverized coal is conveyed from atmospheric pressure to a high-pressure pulverized coal feed hopper via the pressurized conveying system, and then fed into the pulverized coal gasifier through multiple coal conveying lines for reaction. The stability and reliability of the pressurized pulverized coal conveying system and the coal conveying line system directly affect the operational stability of the pulverized coal gasifier.

[0004] Typically, the coal conveying system connecting the pulverized coal feeder and the pulverized coal gasifier experiences significant fluctuations due to factors such as the pressure difference between the pulverized coal feeder and the pulverized coal gasifier, the material level in the pulverized coal feeder, and the feeding of pulverized coal from the discharge pulverized coal feeder to the feeder. If the coal conveyor is in the circulation phase before feeding, i.e., the pulverized coal feeder is circulating pulverized coal back to the pulverized coal storage tank through the coal conveyor, this fluctuation will directly affect the next feeding step of the coal conveyor. If the coal conveyor is already connected to the pulverized coal gasifier for feeding, this fluctuation will affect the operational stability of the gasification system.

[0005] Currently, the feed pressure differential for pulverized coal gasification is controlled at 0.6–1.0 MPaG. This means that when feeding is done via a coal line connection between the pulverized coal feeder and the pulverized coal gasifier, the pressure differential between the feeder and the gasifier is always maintained at 0.6–1.0 MPaG. However, depending on the number of coal lines and the configuration and orientation of the feed cone in the pulverized coal feeder, the degree of fluctuation in the coal lines varies. Using a constant pressure differential feeding method leads to mutual interference between different coal lines, causing fluctuations in the coal line flow rate. This seriously affects the normal feeding of the pulverized coal gasifier and the long-term stable operation of the gasification system after feeding. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a feeding control method for a pulverized coal gasifier. In the initial feeding stage, a high pressure differential is used for feeding. After the coal line conveying system stabilizes, the pressure differential is reduced to the normal feeding pressure differential, which greatly reduces the problem of coal line flow fluctuation during the feeding process of the pulverized coal gasifier and greatly shortens the feeding time.

[0007] The technical solution of this invention is as follows:

[0008] A method for controlling the feeding of a pulverized coal gasification furnace, specifically including the following steps:

[0009] (1) When the pulverized coal gasifier is pressurized to 0.5 MPaG, it is ready for feeding. The pressure of the pulverized coal feeder is always greater than the pressure of the pulverized coal gasifier. Before feeding, the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is set at 1.0 to 3.5 MPaG.

[0010] (2) When feeding, the coal lines between the pulverized coal feeder and the pulverized coal gasifier are connected one by one for feeding. The pressure of the pulverized coal gasifier rises rapidly with the reaction, and the pulverized coal feeder is also pressurized synchronously. The pressure difference between the pulverized coal feeder and the pulverized coal gasifier is always maintained at 1.0 to 3.5 MPaG.

[0011] (3) During the feeding period, the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is maintained at 1.0 to 3.5 MPaG until the pressure of the pulverized coal feeder rises to the set normal operating pressure, and then the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is gradually reduced to the normal feeding pressure difference.

[0012] (4) The pulverized coal feeder continues to feed the pulverized coal gasifier through multiple coal lines, and the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is always maintained above the upper limit of the normal feeding pressure difference until the feeding is completed.

[0013] When the pulverized coal feeder begins to feed the pulverized coal gasifier, the pipeline between the pulverized coal discharge tank and the pulverized coal feeder is disconnected and isolated, that is, the pulverized coal discharge tank does not discharge the pulverized coal feeder at this time.

[0014] Before the pulverized coal feeder begins to feed the pulverized coal gasifier, the pressure between the pulverized coal discharge tank and the pulverized coal feeder is always kept in balance, that is, the pressure difference between the pulverized coal discharge tank and the pulverized coal gasifier is also set at 1.0 to 3.5 MPaG.

[0015] The normal operating pressure of the pulverized coal feeder is the maximum working pressure when the pulverized coal feeder is feeding materials.

[0016] The normal feeding pressure difference between the pulverized coal feeder and the pulverized coal gasifier is 0.8 to 1.0 MPaG; the pulverized coal feeder continues to feed the pulverized coal gasifier through multiple coal lines, and always maintains the pressure difference between the pulverized coal feeder and the pulverized coal gasifier above 1.0 MPaG.

[0017] In step (3), the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is gradually reduced, and the rate of pressure reduction is controlled within 2.0 MPaG / h.

[0018] The pulverized coal feeder is equipped with a differential pressure control circuit, and a differential pressure control valve is installed on the differential pressure control circuit to adjust the differential pressure between the pulverized coal feeder and the pulverized coal gasifier.

[0019] Advantages of this invention:

[0020] (1) In the initial stage of feeding the pulverized coal gasifier, the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is set at 1.0 to 3.5 MPaG, which is much higher than the normal feeding pressure difference of 0.8 to 1.0 MPaG. The feeding is carried out with a high pressure difference of 1.0 to 3.5 MPaG, so that the conveying state of pulverized coal is changed from the turbulent state under the low pressure difference to the plug flow state under the high pressure difference. This improves the stability of the dense phase conveying of pulverized coal and ensures that the density and velocity of pulverized coal can remain stable and the fluctuation is greatly reduced after the pulverized coal is switched from the circulation line of the coal line to the normal feeding process. This achieves a seamless switching between the circulation line of the coal line and the feeding process. At the same time, it ensures the stability of the coal line flow rate during the continuous pressure increase of the pulverized coal gasifier after feeding, which greatly shortens the feeding time.

[0021] (2) When the pulverized coal feeder starts feeding the pulverized coal gasifier, the pulverized coal discharge tank does not feed the pulverized coal feeder, thus avoiding the influence of the pulverized coal discharge tank on the pressure of the pulverized coal feeder, ensuring that the pulverized coal feeder feeds the coal stably within the range of the set pressure difference value, and further improving the stability of the coal line operation. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the coal conveying system of the present invention.

[0023] Attached reference numerals: 1-Pulverized coal storage tank, 2-Pulverized coal discharge tank, 3-Pulverized coal feeder, 4-Coal line, 5-Pulverized coal gasifier, 6-Coal line circulation pipeline, 7-Differential pressure control circuit, 8-Pressure control valve, 9-Pressure relief control valve. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] See Figure 1The coal conveying system of the pulverized coal gasifier includes a pulverized coal storage tank 1, a pulverized coal discharge tank 2, and a pulverized coal feed tank 3 connected in sequence. The pulverized coal feed tank 3 is connected to the pulverized coal gasifier 5 through multiple coal lines 4 for feeding and conveying. The pulverized coal feed tank 3 is connected to the pulverized coal storage tank 1 through a coal line circulation pipeline 6. Before the pulverized coal gasifier 5 needs to be fed, multiple coal lines 4 are connected to the pulverized coal storage tank 1 through the coal line circulation pipeline 6 to realize the circulation connection of the coal conveying system.

[0026] A method for controlling the feeding of a pulverized coal gasification furnace, specifically including the following steps:

[0027] (1) When the pulverized coal gasifier 5 is pressurized to 0.5 MPaG, it is ready for feeding. The pressure of the pulverized coal feed tank 3 is always greater than the pressure of the pulverized coal gasifier 5. Before feeding, the pressure difference between the pulverized coal feed tank 3 and the pulverized coal gasifier 5 is set at 1.0~3.5 MPaG, and the pressure difference between the pulverized coal discharge tank 2 and the pulverized coal gasifier 5 is also maintained at 1.0~3.5 MPaG. At the same time, the pipeline between the pulverized coal discharge tank 2 and the pulverized coal feed tank 3 is disconnected. That is, after feeding begins, the pulverized coal discharge tank 2 does not feed into the pulverized coal feed tank 3. The coal feeding tank 3 is equipped with a differential pressure control circuit 7, which includes a differential pressure control valve. The differential pressure control circuit 7 includes a pressure relief pipeline connected to the upper part of the coal feeding tank 3 and a pressurization pipeline connected to the discharge cone of the coal feeding tank 3. The differential pressure control valve includes a pressure relief control valve 9 installed on the pressure relief pipeline and a pressurization control valve 9 installed on the pressurization pipeline. The pressure of the coal feeding tank 3 is adjusted by the differential pressure control valve, thereby realizing the adjustment of the pressure difference between the coal feeding tank 3 and the coal gasifier 5.

[0028] (2) When feeding, the coal lines 4 between the pulverized coal feeder 3 and the pulverized coal gasifier 5 are connected one by one for feeding. The pressure of the pulverized coal gasifier 5 rises rapidly with the reaction. At the same time, the pulverized coal feeder 3 is also pressurized synchronously. The pressure difference between the pulverized coal feeder 3 and the pulverized coal gasifier 5 is always maintained at 1.0~3.5MPaG.

[0029] (3) During the feeding period, the pressure difference between the pulverized coal feeder 3 and the pulverized coal gasifier 5 is maintained at 1.0 to 3.5 MPaG until the pressure of the pulverized coal feeder 3 rises to 4.9 to 5.1 MPaG and the pressure of the pulverized coal gasifier 5 is basically maintained at 2.0 to 3.6 MPaG. Then, the pressure difference between the pulverized coal feeder 3 and the pulverized coal gasifier 5 is gradually reduced to 0.8 to 1.0 MPaG.

[0030] (4) The pulverized coal feeder 3 continues to feed the pulverized coal gasifier 5 through multiple coal lines 4, and the pressure difference between the pulverized coal feeder 3 and the pulverized coal gasifier 5 is always maintained above 1.0 MPaG until the feeding is completed.

[0031] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the feeding of a pulverized coal gasification furnace, characterized in that: Specifically, it includes the following steps: (1) When the pulverized coal gasifier is pressurized to 0.5 MPaG, it is ready for feeding. The pressure of the pulverized coal feeder is always greater than the pressure of the pulverized coal gasifier. Before feeding, the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is set at 1.0 ~ 3.5 MPaG. (2) When feeding, the coal lines between the pulverized coal feeder and the pulverized coal gasifier are connected one by one for feeding. The pressure of the pulverized coal gasifier rises rapidly with the reaction, and the pulverized coal feeder is also pressurized synchronously. The pressure difference between the pulverized coal feeder and the pulverized coal gasifier is always maintained at 1.0 ~ 3.5 MPaG. (3) During the feeding period, the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is maintained at 1.0 ~ 3.5 MPaG until the pressure of the pulverized coal feeder rises to the maximum working pressure. Then, the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is gradually reduced to the normal feeding pressure difference. The normal feeding pressure difference is 0.8 ~ 1.0 MPaG. (4) The pulverized coal feeder continues to feed the pulverized coal gasifier through multiple coal lines, and the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is always maintained above 1.0 MPaG until the feeding is completed.

2. The feeding control method for a pulverized coal gasification furnace according to claim 1, characterized in that: When the pulverized coal feeder begins to feed the pulverized coal gasifier, the pipeline between the pulverized coal discharge tank and the pulverized coal feeder is disconnected and isolated, that is, the pulverized coal discharge tank does not discharge the pulverized coal feeder at this time.

3. The feeding control method for a pulverized coal gasification furnace according to claim 2, characterized in that: Before the pulverized coal feeder begins to feed the pulverized coal gasifier, the pressure between the pulverized coal discharge tank and the pulverized coal feeder is always kept balanced, that is, the pressure difference between the pulverized coal discharge tank and the pulverized coal gasifier is also set at 1.0 ~ 3.5 MPaG.

4. The feeding control method for a pulverized coal gasification furnace according to claim 1, characterized in that: In step (3), the pressure difference between the pulverized coal feeder and the pulverized coal gasifier is gradually reduced, and the rate of pressure reduction is controlled within 2.0 MPaG / h.

5. The feeding control method for a pulverized coal gasification furnace according to claim 1, characterized in that: The pulverized coal feeder is equipped with a differential pressure control circuit, and a differential pressure control valve is installed on the differential pressure control circuit to adjust the differential pressure between the pulverized coal feeder and the pulverized coal gasifier.

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