阅读说明：本技术 一种用于煤气化除渣系统的喷淋装置及其应用方法 (Spraying device for coal gasification slag removal system and application method thereof ) 是由 曾令艳 郑智巍 李争起 陈智超 于 2020-07-27 设计创作，主要内容包括：一种用于煤气化除渣系统的喷淋装置及其应用方法,本发明涉及一种用于煤气化除渣系统的喷淋装置,它要解决现有带余热锅炉流程的气化炉运行时熔渣落入渣水中形成水蒸气,水蒸气进入气化炉膛影响气化效率的问题。本发明用于煤气化除渣系统的喷淋装置中气化炉的底部开有气化炉下渣口,下降管的一端与气化炉下渣口连通,下降管的另一端与渣池相连通,喷淋环套设在下降管的外围,沿着喷淋环的圆周方向均匀设置有多个喷淋管,每个喷淋管的一端与喷淋环相连通,喷淋管的另一端与下降管相连通,热电偶伸入下降管中并位于喷淋环的上,渣池与给水系统相连。本发明在灰渣进入渣池前进行喷淋降温,减少了水蒸气的产生,有效提高气化效率和合成气品质。(The invention relates to a spraying device for a coal gasification deslagging system and an application method thereof, and aims to solve the problems that when an existing gasification furnace with a waste heat boiler process runs, molten slag falls into slag water to form water vapor, and the water vapor enters a gasification hearth to influence the gasification efficiency. The invention discloses a spraying device for a coal gasification deslagging system, wherein a gasification furnace slag discharging port is formed at the bottom of a gasification furnace, one end of a downcomer is communicated with the gasification furnace slag discharging port, the other end of the downcomer is communicated with a slag bath, a spraying ring is sleeved on the periphery of the downcomer, a plurality of spraying pipes are uniformly arranged along the circumferential direction of the spraying ring, one end of each spraying pipe is communicated with the spraying ring, the other end of each spraying pipe is communicated with the downcomer, a thermocouple extends into the downcomer and is positioned on the spraying ring, and the slag bath is connected with a water supply system. The invention reduces the temperature by spraying before the ash enters the slag pool, reduces the generation of water vapor and effectively improves the gasification efficiency and the quality of the synthesis gas.)

1. The spraying device for the coal gasification deslagging system is characterized by comprising a gasification furnace (2), a waste heat boiler (1), a spraying system, a water supply system and a temperature measuring system, wherein a U-shaped gasification reaction zone is formed between the gasification furnace (2) and the waste heat boiler (1) through a horizontal flue, a gasification furnace lower deslagging port (3) is formed at the bottom of the gasification furnace (2), one end of a downcomer (5) is communicated with the gasification furnace lower deslagging port (3), and the other end of the downcomer (5) is communicated with a slag pool (9);

the spraying system comprises at least one spraying ring (7), the spraying ring (7) is sleeved on the periphery of the descending pipe (5), a plurality of spraying pipes (10) are uniformly arranged along the circumferential direction of the spraying ring (7), one end of each spraying pipe (10) is communicated with the spraying ring (7), the other end of each spraying pipe (10) is communicated with the descending pipe (5), and the communication ports of the spraying pipes (10) and the descending pipe (5) are spraying holes (14);

the temperature measuring system comprises a plurality of thermocouples (4), and the thermocouples (4) extend into the downcomer (5) and are positioned at the upper part of the spray ring (7);

the water supply system comprises a water inlet pipe (8), a water pump (12) and a flowmeter (13), wherein one end of the water inlet pipe (8) is communicated with a spraying ring (7), the other end of the water inlet pipe (8) is communicated with a water spraying source, and the water pump (12) and the flowmeter (13) are sequentially arranged between the water spraying source and the water inlet pipe (8) along the water flow direction.

2. The sprinkling device for the coal gasification deslagging system according to claim 1, wherein an electric valve (11) is arranged on the water inlet pipe (8).

3. The spraying device for the coal gasification deslagging system of claim 1, wherein the temperature measuring system further comprises a DCS system (6), and the thermocouple (4), the electric valve (11), the flow meter (13) and the water pump (12) are connected with the DCS system (6) through control lines.

4. The sprinkling device for the coal gasification deslagging system according to claim 1, wherein the sprinkling pipe (10) is horizontally arranged.

5. The spraying device for the coal gasification deslagging system according to claim 1, wherein 2-4 spraying rings (7) are arranged along the height direction of the downcomer (5).

6. The sprinkling device for the coal gasification deslagging system according to claim 1, wherein each sprinkling pipe (10) is arranged in a radial direction of the sprinkling ring (7).

7. The method for removing the slag by using the spraying device for the coal gasification slag removal system is characterized by comprising the following steps of:

when the gasification furnace normally operates, coal powder and a gasification agent enter the gasification furnace (2), gasification reaction is carried out in the gasification furnace (2) to generate synthesis gas and liquid slag, and a part of the liquid slag is deposited on a water-cooled wall in a hearth of the gasification furnace (2), falls along the water-cooled wall and enters a slag pool (9) through a gasification furnace slag discharging port (3) and a down pipe (5);

the rest of liquid slag and the synthesis gas form mixed gas flow which enters a waste heat boiler (1), the mixed gas flow in the waste heat boiler (1) absorbs heat by a water cooling wall, the temperature is reduced, and the liquid slag in part of the mixed gas flow falls down along the water cooling wall and flows back to a gasification furnace (2) and enters a downcomer (5) through a slag discharge port (3) at the lower part of the gasification furnace (2);

secondly, liquid slag flows to the upper part of the spray ring (7), the temperature of the slag in the downcomer (5) is measured through the thermocouples (4), when the temperature detected by the thermocouples (4) is lower than the rated temperature under the normal working condition, the frequency of the water pump (12) is improved, the water supply quantity of the spray ring (7) is increased, water in the spray ring (7) is sprayed into the downcomer (5) through the spray holes (14), spray water is continuously sprayed out to form a water curtain, water vapor ascending from the slag pool (9) is intercepted, and therefore slag removal of the coal gasification system is completed.

8. The method for removing slag by using the spraying device for the coal gasification slag removal system according to claim 7, wherein the gasifying agent used in the operation of the gasification furnace (2) in the step one is oxygen or a mixed gas of oxygen and steam.

9. The method for deslagging by applying the spray device for the coal gasification deslagging system according to claim 7, wherein the slag temperature signal measured by the thermocouple (4) in the second step is transmitted back to the DCS (6), and the water spraying amount of the spray ring (7) is controlled by the DCS (6).

10. The deslagging method by using the spray device for the coal gasification deslagging system according to claim 7, wherein in the second step, when the temperature detected by the thermocouple (4) is lower than the rated temperature under the normal working condition and the difference value is greater than 2 ℃, the water spraying amount of the spray ring (7) is increased.

Technical Field

The invention relates to a spraying device for a coal gasification deslagging system and a deslagging method using the spraying device.

Background

China is a country rich in coal, poor in oil and low in gas, and the characteristic determines that coal occupies a dominant position in disposable energy production and consumption and cannot be changed for a long time. Coal accounts for more than half of the composition of primary energy production and consumption all the time. The use mode of direct combustion of coal can cause serious pollution to the ecological environment. The coal gasification technology is an important clean coal technology, and industrial fuel gas, civil fuel gas, chemical synthetic raw material gas, synthetic fuel oil raw material gas, hydrogen fuel cells, synthetic natural gas, rocket fuel and the like can be produced by utilizing the coal gasification technology. The current major coal gasification technologies include moving bed (fixed bed) gasification, fluidized bed gasification, entrained flow bed gasification and molten bed gasification, wherein the entrained flow bed gasification technology has become the main development direction of coal gasification technology due to the advantages of high gasification intensity, large single-furnace production capacity, wide coal type application range, high carbon conversion rate and the like.

The flow of the gasification furnace can be divided into a chilling flow and a waste heat boiler flow. Wherein the chilling process is to directly cool and wash the high-temperature synthesis gas discharged from the gasification furnace chamber and then put the synthesis gas into use. In the process of the waste heat boiler, the synthesis gas is subjected to heat exchange through the waste heat boiler after coming out of the gasification furnace, so that the sensible heat of the synthesis gas can be effectively recovered, and the energy utilization efficiency is improved. The U-shaped gasification furnace mentioned in the article is that a horizontal flue is arranged at the bottom of the gasification furnace chamber and the waste heat boiler to connect with each other. The gasification hearth, the horizontal flue and the waste heat boiler form a U-shaped gasification reaction area, the U-shaped gasification can increase the space of gasification reaction, prolong the gasification reaction time and effectively improve the efficiency. However, when the working condition fluctuates, the situation that the horizontal flue is blocked may occur, and the stable operation of the equipment is affected.

In addition, in the existing waste heat boiler flow entrained flow coal gasification technology, slag is discharged from a gasification furnace and directly falls into a slag pool, and slag water quickly absorbs a large amount of heat and turns into water vapor which goes upwards along a downcomer and enters the gasification furnace. The introduction of steam into the hearth can not only destroy the originally stable flow field in the furnace, but also reduce the gasification reaction temperature, and cause the problems of unsmooth slag discharge, blockage of a slag discharge port and the like while affecting the quality of the synthesis gas.

Disclosure of Invention

The invention provides a spraying device for a coal gasification slag removal system and an application method thereof, aiming at solving the problems that when an existing gasification furnace with a waste heat boiler flow is operated, molten slag falls into slag water to form steam, and the steam enters a gasification hearth to influence the gasification efficiency and the quality of synthesis gas, and the slag removal is not smooth and blocks a slag discharge hole.

The spraying device for the coal gasification deslagging system comprises a gasification furnace, a waste heat boiler, a spraying system, a water supply system and a temperature measuring system, wherein a U-shaped gasification reaction zone is formed between the gasification furnace and the waste heat boiler through a horizontal flue, a gasification furnace slag discharging port is formed in the bottom of the gasification furnace, one end of a down pipe is communicated with the gasification furnace slag discharging port, and the other end of the down pipe is communicated with a slag pool;

the spraying system comprises at least one spraying ring, the spraying ring is sleeved on the periphery of the downcomer, a plurality of spraying pipes are uniformly arranged along the circumferential direction of the spraying ring, one end of each spraying pipe is communicated with the spraying ring, the other end of each spraying pipe is communicated with the downcomer, and the communication ports of the spraying pipes and the downcomer are spraying holes;

the temperature measuring system comprises a plurality of thermocouples, and the thermocouples extend into the downcomer and are positioned at the upper part of the spray ring;

the water supply system comprises a water inlet pipe, a water pump and a flowmeter, wherein one end of the water inlet pipe is communicated with the spray ring, the other end of the water inlet pipe is communicated with a water spray source, and the water pump and the flowmeter are sequentially arranged between the water spray source and the water inlet pipe along the water flow direction.

The invention discloses a method for removing slag by using a spraying device of a coal gasification slag removal system, which is realized according to the following steps:

when the gasification furnace normally operates, coal powder and a gasification agent enter the gasification furnace, gasification reaction is carried out in the gasification furnace to generate synthesis gas and liquid slag, and a part of the liquid slag is deposited on a water-cooled wall in a hearth of the gasification furnace, falls down along the water-cooled wall and enters a slag pool through a slag outlet and a down pipe of the gasification furnace;

the rest liquid slag and the synthesis gas form mixed gas flow to enter a waste heat boiler, the mixed gas flow in the waste heat boiler absorbs heat by a water-cooled wall, the temperature is reduced, and the liquid slag in part of the mixed gas flow falls down along the water-cooled wall and flows back to the gasification furnace and enters a downcomer through a slag discharging port below the gasification furnace;

and secondly, liquid slag flows to the upper part of the spray ring, the temperature of the slag in the downcomer (at the section) is measured by a plurality of thermocouples, when the temperature detected (returned) by the thermocouples is lower than the rated temperature under the normal working condition, the fact that water vapor ascends is proved, the frequency of a water pump is improved, the water supply quantity of the spray ring is increased, water in the spray ring is sprayed into the downcomer through the spray holes, the spray water is continuously sprayed out to form a layer of water curtain, the water vapor ascending from the slag pool is intercepted, and therefore slag removal of the coal gasification system is completed.

The spraying device for the coal gasification slag removal system and the application method thereof have the following beneficial effects:

firstly, the invention can effectively improve the gasification efficiency and the quality of the synthesis gas:

during the operation of the gasification furnace, the temperature of the molten ash is about 1100 ℃, the high-temperature molten slag falls into a slag pool, and water in the slag pool quickly absorbs heat and evaporates to generate a large amount of water vapor. When the water vapor is continuously generated, the pressure gradually rises, and the water vapor is further caused to ascend into the gasification furnace. The water vapor which continuously moves upwards can destroy the originally stable flow field of the gasification furnace, and meanwhile, the gasification temperature can also be obviously reduced, so that the final gasification efficiency and the effective gas components in the synthesis gas are obviously reduced, and the subsequent industrial application of the synthesis gas is influenced. The ash and slag spraying and cooling device provided by the invention reduces the generation of water vapor by spraying and cooling the ash and slag before entering the slag pool, and the water vapor ascending in the slag pool is cooled and liquefied due to the existence of spraying water, and then falls back into the slag pool again. Therefore, the invention can effectively prevent the water vapor in the slag pool from entering the gasification furnace, thereby ensuring the gasification efficiency and the quality of the synthesis gas.

Secondly, the invention can effectively prevent the blockage of the slag discharging opening of the gasification furnace:

when the gasification furnace normally operates, ash in the pulverized coal particles in the furnace is rapidly melted at a high temperature to form liquid slag, and the liquid slag falls into a slag pool to generate a large amount of water vapor. The temperature of the upward steam is lower, the temperature of the slag is reduced after heat exchange with the upward steam, the fluidity of the slag is reduced finally, and the slag outlet is easy to block. The spray ring provided by the invention intercepts water vapor, and can prevent the fluidity of slag at the slag outlet from being deteriorated due to heat exchange between the water vapor and the slag, thereby effectively reducing the possibility of blockage.

The service life of the downcomer can be effectively prolonged:

when the equipment normally operates, high-temperature slag flows in the downcomer and generates a large amount of water vapor after falling into the slag pool. When the water vapor in the slag pool rushes to the gasification furnace, the temperature of the downcomer is reduced under the influence of the water vapor. When a subsequent slag salvaging system is started, the pressure of a slag pool changes, the ascending amount of steam also fluctuates, and the temperature of a downcomer also fluctuates. Long-term repetition can lead to thermal fatigue of the downcomer, increasing the risk of breakage. The spraying device of the invention blocks the upward steam, thereby avoiding the steam from passing through the downcomer and reducing the risk of damage.

The invention can increase the system operation cycle, avoid frequent start and stop, and improve the efficiency:

during operation of the gasification furnace, slag blockage caused by dropping of large slag blocks is an important reason for frequent starting and stopping of equipment. Although the existing gasification equipment is generally provided with a slag crusher at the outlet of the slag pool, the actual use effect is not ideal. Meanwhile, at the tail end of the descending pipe, due to the fact that the temperature is reduced, slag is easy to solidify and adhere to the outlet of the descending pipe, and blockage is caused. The spraying system is arranged in the invention, and before the slag falls into the slag pool, the slag is dispersed by spraying water, so that the generation of large slag can be effectively prevented, and the possibility of large slag block blockage in the subsequent treatment process is reduced; the spray holes are arranged near the tail end of the downcomer, and the spray water continuously washes the wall of the downcomer, so that the slagging of the wall of the downcomer can be effectively avoided, and the outlet of the downcomer is prevented from being blocked. Therefore, the invention can effectively increase the equipment operation period, avoid frequent start-stop and has better economy and efficiency.

Drawings

FIG. 1 is a schematic structural diagram of a spraying device for a coal gasification deslagging system according to the invention;

FIG. 2 is a schematic structural view of a spray ring;

fig. 3 is a schematic structural view of a plurality of spray rings according to the fifth embodiment.

Detailed Description