A coal ash slag cooling and slag discharge system

Abstract

The invention discloses a coal ash cooling and slag discharge system, which comprises a cold slag tank, a slag collecting tank and a slag discharge tank, the outlet of the ash pipe extends to the inner bottom of the cold slag tank, an ash temperature sensor is installed inside the top of the ash pipe, a cooling water pipe is connected to the water inlet pipe of the cold slag tank, a water inlet control valve is installed on the water inlet pipe, an air charging pipe is connected to the upper part of the ash pipe inside the cold slag tank, the cooling air pipe is connected to the air charging pipe, an air charging control valve is installed on the air charging pipe, and a cold slag tank pressure sensor and a cold slag tank temperature sensor are installed on the top of the cold slag tank. The advantages of the invention are that carbon dioxide is introduced into the ash pipe instead of steam to control the slag discharge speed, and the ash is cooled once, which reduces the use of steam, reduces the investment cost of steam manufacturing equipment and raw coal, and after carbon dioxide enters the fluidized bed gasifier, it can inhibit the reaction of carbon and oxygen in the fluidized bed gasifier to generate carbon dioxide, and promote the reaction of carbon and water vapor.

Description

Technical field:

[0001] The invention relates to a slag discharge device, in particular to a coal ash slag cooling and slag discharge system. Background technology:

[0002] In the fluidized bed gasifier, coal powder reacts with gasifying agent to generate raw coal gas, and high-temperature ash is generated after coal powder is gasified. In order to discharge the ash in the fluidized bed gasifier, the slag discharge port of the fluidized bed gasifier is generally connected to the quenching chamber and the slag discharge tank in sequence. The slag discharge process is as follows: the ash in the fluidized bed gasifier enters the slag discharge channel through the slag discharge port, steam is passed into the slag discharge channel to control the slag discharge speed, and cooling water is passed into the slag discharge channel to cool the ash in the descending process. The ash and cooling water fall into the quenching chamber from the slag discharge channel together, and the ash cooled in the quenching chamber is discharged through the slag discharge tank; in the above process, the slag discharge speed is generally controlled by adding superheated steam to the slag discharge channel, and the ash is cooled by passing cooling water into the slag discharge channel. 90% of the heat in the ash is transferred to the cooling water in the form of sensible heat, and the cooling water is forced to circulate through a circulating pump, and the heat is removed by a heat exchanger.

[0003] The above-mentioned slag discharge device has the following problems during use: 1. The ash needs to be cooled in the quenching chamber for a period of time, and the quenching chamber is continuously fed with slag. When the cooling water level in the quenching chamber exceeds the water outlet, it is necessary to use a circulating pump for forced circulation. The cooling water will contain some ash, which will cause blockage of the circulating pump and the heat exchanger during the circulating cooling process, causing the slag discharge device to be interrupted, affecting the slag discharge efficiency; 2. The ash in the slag discharge tank falls into the slag storage device by its own weight. The slag storage device can only be placed under the slag discharge tank. The equipment placement position is limited, and the overall height of the slag discharge equipment is relatively high, which is not convenient for inspection and maintenance; 3. Steam is introduced into the slag discharge channel to control the slag discharge speed, which increases the use of steam. The steam needs to be produced by a steam boiler, which increases the investment cost of equipment and raw coal; 4. Cooling water is passed into the slag discharge channel to cool the ash, but the slag cannot be completely immersed in the cooling water, resulting in poor cooling effect. Summary of the invention:

[0004] The object of the present invention is to provide a coal ash cooling and slag removal system which can reduce the amount of steam supplied to the fluidized bed gasifier, suppress the generation of carbon dioxide in the gasification reaction by adding room temperature carbon dioxide gas in the ash pipe, and improve the raw coal gasification efficiency.

[0005] The present invention is implemented by the following technical scheme: a coal ash cooling and slag discharge system, which includes a slag cooling tank, a slag collecting tank and a slag discharge tank, the outlet of the slag pipe extends to the inner bottom of the slag cooling tank, an ash temperature sensor is installed inside the top of the slag pipe, a cooling water pipe is connected to the water inlet pipe of the slag cooling tank, a water inlet control valve is installed on the water inlet pipe, an air charging pipe is connected to the upper part of the slag pipe inside the slag cooling tank, the cooling air pipe is connected to the air charging pipe, an air charging control valve is installed on the air charging pipe, and a slag cooling tank pressure sensor and a slag cooling tank temperature sensor are installed on the top of the slag cooling tank;

[0006] The slag discharge port at the bottom of the cold slag tank is connected with the slag inlet at the top of the slag collecting tank, and a water balance valve is installed on the top of the slag collecting tank; the slag discharge port at the bottom of the slag collecting tank is connected with the slag inlet at the top of the slag discharge tank through a first slag discharge valve, a pressure relief valve and a slag discharge tank pressure sensor are installed on the top of the slag discharge tank, a slag discharge liquid level sensor is installed on the side of the slag discharge tank, a second slag discharge valve is installed at the bottom of the slag discharge tank, the second slag discharge valve is connected with the slag discharge main pipe, and a water injection valve is installed on the slag discharge tank above the second slag discharge valve.

[0007] Furthermore, a connecting pipe is connected between the cooling water pipe and the water injection valve, and a control valve is installed on the connecting pipe.

[0008] Furthermore, the connecting pipe at the outlet end of the control valve is connected to the slag discharge main pipe through a slag flushing valve, and the outlet end of the pressure relief valve is connected to the inlet of the slag discharge main pipe.

[0009] Furthermore, the outlet end of the water balance valve is connected to the connecting pipe at the outlet end of the control valve, and the connecting pipe at the inlet end of the control valve is connected to the inlet end of the water balance valve through a slag collecting tank flushing valve.

[0010] Furthermore, the ash temperature sensor, the cold slag tank temperature sensor, the cold slag tank pressure sensor, the slag discharge tank pressure sensor, and the slag discharge liquid level sensor are all electrically connected to the input end of the controller, and the output end of the controller is electrically connected to the water inlet control valve, the inflation control valve, and the pressure relief valve, respectively.

[0011] Furthermore, the cold slag tank includes a tank body, the ash pipe is vertically arranged in the middle of the tank body, the top end of the ash pipe extends to the outside of the top end of the tank body, and a channel is formed between the bottom end of the ash pipe and the bottom end of the tank body; a high liquid level sensor is arranged inside the tank body below the inflation pipe; a plurality of balancing holes are opened in a circumferential direction on the ash pipe below the high liquid level sensor, a low liquid level sensor is arranged inside the tank body below the balancing hole, and both the high liquid level sensor and the low liquid level sensor are electrically connected to the water inlet control valve and the water balancing valve; the water inlet pipe is connected to the side of the tank body, an annular water distribution pipe connected to the water inlet pipe is arranged on the outside of the ash pipe, and a plurality of water distribution holes are opened on the pipe wall of the annular water distribution pipe.

[0012] Furthermore, the ash pipe includes a straight tube heat exchange section, an expanded tube vaporization section and a straight tube slag discharge section which are sequentially connected from top to bottom, the inflation pipe is arranged in the straight tube heat exchange section, and the balance hole is opened in the upper part of the expanded tube vaporization section.

[0013] Furthermore, an air distribution pipe is embedded and installed on the ash pipe above the high liquid level sensor, and the air filling pipe is connected with the ash pipe through the air distribution pipe; the air distribution pipe includes an annular sintered metal filter element and a tube body separately sleeved on the outside of the sintered metal filter element, the tube body is embedded and installed on the ash pipe, and the top and bottom ends of the tube body are respectively connected to the ash pipe through flanges, and the air filling pipe is connected with the inside of the tube body.

[0014] Furthermore, a fire-resistant layer is provided on the inner wall of the ash pipe outside the tank body.

[0015] Furthermore, a grate plate is fixed between the lower outer wall of the ash pipe and the inner wall of the tank body, and a manhole is provided on the side wall of the tank body.

[0016] Furthermore, the inflation tube is a carbon dioxide inflation tube.

[0017] The advantages of the present invention are as follows: 1. The cooling water at the liquid level in the ash pipe is continuously evaporated into steam, and the steam performs secondary cooling on the ash, and the steam enters the fluidized bed gasifier through the ash pipe for utilization, which reduces the external steam supply by 5% and reduces the steam investment cost; after the cooling water evaporates, low-temperature cooling water will be replenished, and there is no need to force the cooling water to circulate and cool down, which avoids the blockage of the circulation pump and the heat exchanger during the circulation cooling process, ensures the smooth operation of the slag discharge device, and ensures the slag discharge efficiency; 2. The slag in the slag discharge main pipe is transported by high-pressure water and can be transported along the slag discharge main pipe to the slag storage device at the end of the slag discharge main pipe, so that the placement position of the slag storage device is not restricted, the overall height of the slag discharge equipment is reduced, and it is convenient for inspection and maintenance; 3. Carbon dioxide is introduced into the ash pipe instead of steam to control the slag discharge speed, and the slag is cooled once, which reduces the use of steam and reduces the investment cost of steam manufacturing equipment and raw coal. Moreover, after the carbon dioxide enters the fluidized bed gasifier, the slag in the fluidized bed gasifier is The increase in carbon dioxide concentration can inhibit the reaction of carbon and oxygen in the fluidized bed gasifier to generate carbon dioxide, promote the reaction of carbon and water vapor, and increase the effective gas component content of the raw coal gas; 4. After the ash enters the tank, it falls into and is immersed in the cooling water. The cooling water can fully cool the ash and ensure the cooling effect; 5. A number of balancing holes are opened in the circumferential direction of the middle part of the ash pipe, which can balance the pressure on the upper part of the tank and the inside of the ash pipe, avoiding the cooling water pressure when the pressure on the upper part of the tank is greater than the pressure inside the ash pipe. Enter the fluidized bed gasifier to ensure safe production; 6. The ash pipe includes a straight tube heat exchange section, an expanded tube vaporization section and a straight tube slag discharge section which are connected in sequence from top to bottom. The diameters of the expanded tube vaporization section and the straight tube slag discharge section are larger than the diameter of the straight tube heat exchange section, which can limit the diffusion of high-temperature ash in the cooling water, and can limit the diffusion of fly ash that is not easily soluble in water in the ash, forcing it to be wetted; and fully collect the steam generated by the absorption of heat by the cooling water, and the steam enters the fluidized bed gasifier through the ash pipe to be used as a gasifying agent, thereby reducing the investment cost of the gasifying agent. Description of the drawings:

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the cold slag tank;

[0020] Figure 3 This is a schematic diagram of the structure of the air distribution pipe.

[0021] Slag cooling tank 1, slag collecting tank 2, slag discharge tank 3, ash pipe 4, ash temperature sensor 5, cooling water pipe 6, water inlet pipe 7, water inlet control valve 8, cooling air pipe 9, charging pipe 10, charging control valve 11, slag cooling tank pressure sensor 12, water balance valve 13, first slag discharge valve 14, pressure relief valve 15, slag discharge tank pressure sensor 16, slag discharge liquid level sensor 17, water injection valve 18, second slag discharge valve 19, slag discharge main pipe 20, connecting pipe 2 1. Control valve 22, slag flushing valve 23, slag tank flushing valve 24, controller 25, tank body 26, air distribution pipe 27, high liquid level sensor 28, balance hole 29, low liquid level sensor 30, manhole 31, annular water distribution pipe 32, water distribution hole 33, straight tube heat exchange section 34, expanded diameter tube vaporization section 35, straight tube slag discharge section 36, sintered metal filter element 37, tube body 38, refractory layer 39, grate plate 40, cold slag tank temperature sensor 41. Specific implementation method:

[0022] Embodiment 1:

[0023] like Figure 1-3 As shown, a coal ash slag cooling and slag discharge system comprises a slag cooling tank 1, a slag collecting tank 2 and a slag discharge tank 3.

[0024] The cold slag tank 1 includes a tank body 26, in the middle of which an ash pipe 4 is vertically arranged, the top end of the ash pipe 4 extends to the outside of the top end of the tank body 26, the outlet of the ash pipe 4 extends to the inner bottom of the cold slag tank 1, and a channel is formed between the bottom end of the ash pipe 4 and the bottom end of the tank body 26, and the ash falls into the tank body 26 through the ash pipe 4 for cooling.

[0025] The ash pipe 4 includes a straight tube heat exchange section 34, an expanded tube vaporization section 35 and a straight tube slag discharge section 36 which are connected in sequence from top to bottom. The diameters of the expanded tube vaporization section 35 and the straight tube slag discharge section 36 are larger than the diameter of the straight tube heat exchange section 34, which can limit the diffusion of high-temperature ash in the cooling water and the diffusion of fly ash that is not easily soluble in water in the ash, forcing it to be wetted.

[0026] The upper part of the ash pipe 4 inside the cold slag tank 1 is connected with an air charging pipe 10, which is arranged in the straight tube heat exchange section 34, and the cooling air pipe 9 is connected with the air charging pipe 10. When the ash flows through the straight tube heat exchange section 34, the air charging pipe 10 introduces cooling air into the ash pipe 4 to cool the ash once. After the primary cooling, the ash continues to flow down along the ash pipe 4. When it contacts the cooling water in the ash pipe 4, the cooling water absorbs heat and evaporates to generate a large amount of steam. The steam performs secondary cooling on the ash in the ash pipe 4. The steam after the secondary cooling of the ash enters the fluidized bed gasification furnace through the ash pipe 4 for utilization, which reduces the external steam supply by 5% and reduces the investment cost of the gasification agent. After the cooling water evaporates, low-temperature cooling water will be added, and there is no need to force the cooling water to circulate and cool it down, which avoids the blockage of the circulation pump and the heat exchanger during the circulation cooling process, ensures the smooth operation of the slag discharge device, and ensures the slag discharge efficiency.

[0027] An air distribution pipe 27 is embedded and installed on the ash pipe 4, and the charging pipe 10 is connected to the ash pipe 4 through the air distribution pipe 27. The air distribution pipe 27 includes an annular sintered metal filter element 37 and a tube body 38 separately sleeved on the outside of the sintered metal filter element 37. The sintered metal filter element 37 can prevent ash from entering the inside of the tube body 38 to avoid clogging the charging pipe 10. The tube body 38 is embedded and installed on the ash pipe 4, and the top and bottom ends of the tube body 38 are respectively connected to the ash pipe 4 through flanges, and the charging pipe 10 is connected to the inside of the tube body 38. An air charging control valve 11 is installed on the charging pipe 10, and an ash temperature sensor 5 is installed inside the top of the ash pipe 4. The ash temperature sensor 5 detects the temperature of the ash discharged from the fluidized bed gasification furnace. When the temperature is higher than the preset value of the controller 25, it will send an opening increase signal to the charging control valve 11 to increase the amount of cooling gas entering. The inflation pipe 10 is a carbon dioxide inflation pipe, which uses carbon dioxide gas instead of steam as cooling gas, thereby reducing the use of steam and the investment cost of steam manufacturing equipment and raw coal. In addition, after the carbon dioxide enters the fluidized bed gasifier, the carbon dioxide concentration in the fluidized bed gasifier increases, which can inhibit the reaction of carbon and oxygen in the fluidized bed gasifier to generate carbon dioxide, promote the reaction of carbon and water vapor, and increase the effective gas component content of the raw coal gas.

[0028] The side of the tank body 26 is connected with a water inlet pipe 7, and the cooling water pipe 6 is connected with the water inlet pipe 7, and cooling water is introduced into the cold slag tank 1. The ash after secondary cooling falls into the tank body 26 and is immersed in the cooling water for tertiary cooling. A water inlet control valve 8 is installed on the water inlet pipe 7, and a cold slag tank temperature sensor 41 is installed on the top of the cold slag tank 1. The cold slag tank temperature sensor 41 is used to detect the temperature of the cooling water and ash inside the cold slag tank 1. When the temperature is higher than the preset value of the controller 25, an opening increase signal will be sent to the water inlet control valve 8 to increase the amount of cooling water entering.

[0029] An annular water distribution pipe 32 connected to the water inlet pipe 7 is sleeved on the outside of the ash pipe 4, and a plurality of water distribution holes 33 are opened on the pipe wall of the annular water distribution pipe 32 to ensure that the cooling water is evenly added to the tank body 26, and the liquid level and ambient temperature of each part of the tank body 26 are uniform, which is conducive to the regulation of the temperature and pressure of the cooling system. The water distribution holes 33 are opened in all directions of the annular water distribution pipe 32, and when the cooling water is sprayed onto the side wall of the tank body 26, the side wall of the tank body 26 can be cooled.

[0030] A high liquid level sensor 28 is provided inside the tank body 26 below the gas distribution pipe 27 and the charging pipe 10. The high liquid level sensor 28 is arranged below the charging pipe 10 to prevent the liquid level inside the ash pipe 4 from exceeding the charging pipe 10, thereby ensuring that the cooling gas enters the ash pipe 4 normally. On the ash pipe 4 below the high liquid level sensor 28, a plurality of balancing holes 29 are opened in the circumferential direction, and the balancing holes 29 are opened at the upper part of the vaporization section 35 of the expansion pipe. The pressure on the upper part of the tank body 26 and the inside of the ash pipe 4 is balanced to prevent the cooling water from being pressed into the fluidized bed gasifier through the ash pipe 4 when the pressure on the upper part of the tank body 26 is greater than the pressure inside the ash pipe 4, so as to ensure safe production; a low liquid level sensor 30 is provided inside the tank body 26 below the balancing hole 29, and the high liquid level sensor 28 and the low liquid level sensor 30 are both electrically connected to the water inlet control valve 8 and the water balance valve 13 on the slag collecting tank 2. The high liquid level sensor 28 is used to detect whether the liquid level inside the tank body 26 reaches the upper limit of the liquid level, and the low liquid level sensor 30 is used to detect whether the liquid level inside the tank body 26 reaches the upper limit of the liquid level. Whether it reaches the lower limit of the liquid level; when the low liquid level sensor 30 detects that the cooling water level inside the cold slag tank 1 reaches the preset lower limit of the liquid level, the opening of the water inlet control valve 8 is increased, and the opening of the water balance valve 13 is decreased to replenish water to the tank body 26; when the high liquid level sensor 28 detects that the cooling water level reaches the preset upper limit of the liquid level, the opening of the water inlet control valve 8 is decreased, and the opening of the water balance valve 13 is increased, so that the cooling water level inside the tank body 26 is always maintained between the lowest liquid level and the highest liquid level, so that the coal slag can be immersed in the cooling water to ensure a good cooling effect. The function of the high liquid level sensor 28 and the low liquid level sensor 30 in this embodiment is to detect the liquid level height, which is a conventional function of the liquid level sensor, and its model is MC1151 / 3351DP.

[0031] A grate plate 40 is fixed between the lower outer wall of the ash pipe 4 and the inner wall of the tank body 26, which can prevent the ash in the cooling water from floating upward and blocking the balance hole 29 on the ash pipe 4, thereby ensuring the pressure balance between the upper part of the tank body 26 and the inside of the ash pipe 4. A manhole 31 is provided on the side wall of the tank body 26 to facilitate maintenance of the inside of the tank body 26. A cold slag tank pressure sensor 12 is installed on the top of the cold slag tank 1, and the cold slag tank pressure sensor 12 is used to detect the air pressure inside the cold slag tank 1.

[0032] The slag discharge port at the bottom of the cold slag tank 1 is connected with the slag inlet at the top of the slag collecting tank 2. A water balance valve 13 is installed on the top of the slag collecting tank 2. The cooling water and ash in the cold slag tank 1 enter the slag collecting tank 2. The ash is deposited to the bottom of the slag collecting tank 2. The water balance valve 13 is opened to discharge the excess water on the upper part of the slag collecting tank 2. The water discharged through the water balance valve 13 is divided into two paths, one is used as a water replenishment source for the slag discharge tank 3, and the other is used as a slag discharge water source for the slag discharge main pipe 20.

[0033] The slag discharge port at the bottom of the slag collecting tank 2 is connected to the slag inlet at the top of the slag discharge tank 3 through the first slag discharge valve 14. A pressure relief valve 15 and a slag discharge tank pressure sensor 16 are installed on the top of the slag discharge tank 3. A slag discharge liquid level sensor 17 is installed on the side of the slag discharge tank 3. A second slag discharge valve 19 is installed at the bottom of the slag discharge tank 3. The second slag discharge valve 19 is connected to the slag discharge main pipe 20. A water injection valve 18 is installed on the slag discharge tank 3 above the second slag discharge valve 19. The water is injected into the discharge tank 3 through the water injection valve 18. Water is added to the slag tank 3 to balance the pressure in the slag discharge tank 3 and the slag collection tank 2, and the air pressure inside the slag discharge tank 3 is detected by the slag discharge tank pressure sensor 16. When the slag discharge tank 3 is filled with water, if the detection value of the slag discharge tank pressure sensor 16 is greater than the detection value of the cold slag tank pressure sensor 12, the controller 25 controls the pressure relief valve 15 to open and relieve the pressure of the slag discharge tank 3 until the detection value of the slag discharge tank pressure sensor 16 is equal to the cold slag tank pressure sensor 12, and the pressure relief valve 15 is closed. At this time, a high-pressure gas phase space is formed on the top of the slag discharge tank 3. The slag discharge liquid level sensor 17 is used to detect the liquid level inside the slag discharge tank 3 during water injection. When the detection value of the slag discharge liquid level sensor 17 reaches the preset value of the controller 25, the water injection valve 18 is closed to stop water injection; after the water injection is completed, the first slag discharge valve 14 is opened regularly, and the ash at the bottom of the slag collection tank 2 falls into the slag discharge tank 3; when the slag discharge tank 3 is discharged, the pressure relief valve 15 is opened first to relieve the pressure of the slag discharge tank 3 to avoid Too high pressure will have a great impact on the pipeline. To ensure safe slag discharge, the pressure in the slag discharge pipe 3 can be detected by the slag discharge tank pressure sensor 16. When the pressure in the slag discharge pipe 3 is released to the normal system pressure, the pressure relief valve 15 is closed, and the second slag discharge valve 19 and the slag flushing valve 23 are opened. The ash in the slag discharge tank 3 enters the slag discharge main pipe 20 through the second slag discharge valve 19; when the slag discharge in the slag discharge tank 3 is not smooth, the water injection valve 18 is opened to inject water into the slag discharge tank 3 to clear the blockage until the slag discharge is completed.

[0034] A connecting pipe 21 is connected between the cooling water pipe 6 and the water injection valve 18, and a control valve 22 is installed on the connecting pipe 21. When the control valve 22 and the water injection valve 18 are opened, part of the cooling water sent by the cooling water pipe 6 is used as a replenishing water source for the slag discharge tank 3. The connecting pipe 21 at the outlet end of the control valve 22 is connected with the slag discharge main pipe 20 through a slag flushing valve 23. When the slag flushing valve 23 is opened, part of the cooling water sent by the cooling water pipe 6 is used to flush the ash flowing through the pipeline or the cooling water is used as slag discharge water for the slag discharge main pipe 20. The outlet end of the pressure relief valve 15 is connected with the inlet of the slag discharge main pipe 20, and the gas discharged from the slag discharge tank 3 is discharged into the slag discharge main pipe 20 to disturb the ash and ensure that the ash has good fluidity in the slag discharge main pipe 20.

[0035] The outlet end of the water balancing valve 13 is connected to the connecting pipe 21 at the outlet end of the control valve 22. By opening the water balancing valve 13 and the slag flushing valve 23, the cooling water after heat exchange discharged from the slag collecting tank 2 can be used as the slag discharge water of the slag discharge main pipe 20; by opening the water balancing valve 13 and the water injection valve 18, the cooling water after heat exchange discharged from the slag collecting tank 2 can be used as the replenishment water source for the slag discharge tank 3. The connecting pipe 21 at the inlet end of the control valve 22 is connected to the inlet end of the water balancing valve 13 through the slag collecting tank flushing valve 24. By opening the slag collecting tank flushing valve 24, part of the cooling water delivered by the cooling water pipe 6 can be used to flush the inlet pipeline of the water balancing valve 13.

[0036] The ash temperature sensor 5, the cold slag tank temperature sensor 41, the cold slag tank pressure sensor 12, the slag discharge tank pressure sensor 16, and the slag discharge liquid level sensor 17 are all electrically connected to the input end of the controller 25, and the output end of the controller 25 is electrically connected to the water inlet control valve 8, the inflation control valve 11, and the pressure relief valve 15. The function of the cold slag tank temperature sensor 41 and the ash temperature sensor 5 in this embodiment is to detect the temperature, which is a conventional function of the temperature sensor, and its model is MCT80Y; the function of the cold slag tank pressure sensor 12 and the slag discharge tank pressure sensor 16 in this embodiment is to detect the internal pressure of the tank, which is a conventional function of the pressure sensor, and its model is MC1151 / 3351GP; the function of the slag discharge liquid level sensor 17 in this embodiment is to detect the liquid level height, which is a conventional function of the liquid level sensor, and its model is MC1151 / 3351DP; the function of the controller 25 in this embodiment is to control the corresponding valve according to the received detection value, and its model is S7-400 Siemens PLC controller. The ash temperature sensor 5, the cold slag tank temperature sensor 41, the cold slag tank pressure sensor 12, the slag discharge tank pressure sensor 16, and the slag discharge liquid level sensor 17 transmit the detection values ​​to the controller 25, and the controller 25 adjusts the water inlet control valve 8, the inflation control valve 11, and the pressure relief valve 15 accordingly to control the temperature and pressure of the slag discharge system, reduce labor intensity, and improve work efficiency.

[0037] Working process:

[0038] The ash in the fluidized bed gasifier enters the tank body 26 of the cold slag tank 1 through the ash pipe 4. The ash is cooled once by the carbon dioxide cooling gas discharged from the straight tube heat exchange section 34 of the ash pipe 4 through the sintered metal filter element 37. After the cooling gas cools the ash once, it moves upward along the ash pipe 4 to enter the fluidized bed gasifier. The ash after the primary cooling continues to move downward along the ash pipe 4. After contacting with the cooling water, the cooling water evaporates to produce a large amount of steam. The expanded tube vaporization section 35 and the straight tube slag discharge section 36 limit the diffusion of the high-temperature ash in the cooling water, fully collect the steam generated by the cooling water absorbing heat, and the steam moves upward along the ash pipe 4 to cool the ash for a second time. After the steam cools the ash for a second time, it moves upward along the ash pipe 4 to enter the fluidized bed gasifier. After the ash falls into the cooling water, the cooling water cools it three times. The cooling water is sprayed out through the water distribution holes 33 on the annular water distribution pipe 32 to replenish the cooling water in the tank body 26 . At the same time, part of the cooling water is sprayed onto the inner wall of the tank body 26 , slides down along the inner wall, and cools the inner wall of the tank body 26 .

[0039] The upper space of the tank body 26 is connected to the ash pipe 4 through the balance hole 29, thereby ensuring the pressure balance between the tank body 1 and the ash pipe 2. The grate plate 40 between the lower outer wall of the ash pipe 4 and the inner wall of the tank body 26 can prevent the ash in the cooling water from floating upward and blocking the balance hole 29.

[0040] After three coolings, the ash directly enters the slag collecting tank 2 through the slag discharge port. When the ash in the slag discharge tank 3 is completely discharged, the second slag discharge valve 19 is closed, and the water injection valve 18 is opened to start water injection. When the detection value of the slag discharge liquid level sensor 17 reaches the preset value of the controller 25, the water injection valve 18 is closed. When the detection value of the slag discharge tank pressure sensor 16 is greater than the detection value of the cold slag tank pressure sensor 12, the controller 25 will send an opening signal to the pressure relief valve 15 to relieve the pressure of the slag discharge tank 3. When the detection value of the slag discharge tank pressure sensor 16 is equal to the cold slag tank pressure sensor 12, the pressure relief valve 15 is closed.

[0041] After adjusting the liquid level and pressure inside the slag discharge tank 3 according to the above steps, open the first slag discharge valve 14, and the high-pressure gas at the top of the slag discharge tank 3 moves upward into the slag collecting tank 2, and the ash at the bottom of the slag collecting tank 2 is disturbed and moves downward into the slag discharge tank 3; after the slag discharge tank 3 is fed with materials, close the first slag discharge valve 14, open the pressure relief valve 15, and after the slag discharge tank 3 is vented to normal pressure, open the second slag discharge valve 19 and the slag flushing valve 23, and the slag is smoothly taken away by the high-pressure induced water and flows along the slag discharge main pipe 20 to the slag storage device, and the slag is discharged. The ash in the slag main pipe 20 is transported by high-pressure induced water, and can be transported along the slag discharge main pipe 20 to the slag storage device at the end of the slag discharge main pipe 20, so that the placement position of the slag storage device is not restricted; in the slag feeding and slag discharge process of the slag discharge tank 3, the water balance valve 13 is always in the open state, and the water injected into the slag discharge tank 3 and the conveying water of the slag discharge main pipe 20 are both water discharged from the slag collection tank 2 through the water balance valve 13, so that the water discharged from the slag collection tank 2 is fully utilized to reduce the use of pure water resources.

[0042] The water injected into the slag discharge tank 3 and the conveying water of the slag discharge main pipe 20 are both provided by the water discharged from the slag collection tank 2 through the water balance valve 13. The water discharged from the water balance valve 13 contains a certain amount of ash. It is necessary to regularly open the slag collection tank flushing valve 24 and the control valve 22 to flush the pipeline through which the slag water flows to prevent the pipeline through which the slag water flows from being blocked. The flushing cycle is determined according to the actual working conditions of the system operation.

[0043] When the low liquid level sensor 30 detects that the cooling water level inside the cold slag tank 1 has reached the preset lower limit of the liquid level, the opening of the water inlet control valve 8 is increased, and the opening of the water balance valve 13 is decreased to replenish water to the tank body 26; when the high liquid level sensor 28 detects that the cooling water level has reached the preset upper limit of the liquid level, the opening of the water inlet control valve 8 is decreased, and the opening of the water balance valve 13 is increased, so that the cooling water level inside the tank body 26 is always maintained between the minimum liquid level and the maximum liquid level, so that the coal slag can be immersed in the cooling water, ensuring a good cooling effect.

[0044] When the detection value received by the controller 25 from the cold slag tank temperature sensor 41 exceeds the preset value, the controller 25 will send an opening increase signal to the water inlet control valve 8 to increase the amount of cooling water entering; when the detection value received by the controller 25 from the ash temperature sensor 5 exceeds the preset value, the controller 25 will send an opening increase signal to the inflation control valve 11 to increase the amount of cooling air entering.

[0045] Embodiment 2:

[0046] A method for cooling and discharging coal ash using a coal ash cooling and discharging system in Example 1 comprises the following steps: (1) primary cooling by cooling gas, (2) secondary cooling by steam, (3) tertiary cooling by cooling water, and (4) slag feeding and discharging in a slag discharging tank; wherein:

[0047] (1) Cooling gas primary cooling: the ash discharged from the fluidized bed gasifier at 850°C-900°C enters the ash pipe 4, and the cooling gas carbon dioxide enters the pipe body 38 of the air distribution pipe 27 through the gas charging pipe 10, and then is uniformly sprayed out through the sintered metal filter element 37 to cool the ash in the ash pipe 4. The ash cooled to 450°C-550°C moves downward along the ash pipe 4, and the carbon dioxide after heat exchange with the ash moves upward along the ash pipe 4 into the fluidized bed gasifier; using carbon dioxide instead of steam to control the slag discharge speed, on the one hand, reduces the use of steam, reduces the investment cost of steam manufacturing equipment and raw coal, and at the same time, carbon dioxide and residual carbon in the high-temperature ash undergo an endothermic reduction reaction to further cool the ash. On the other hand, after entering the fluidized bed gasifier, carbon dioxide can inhibit the reaction of carbon and oxygen in the fluidized bed gasifier to generate carbon dioxide, reduce the generation of carbon dioxide, promote the reaction of carbon and water vapor, and increase the effective gas component of the raw coal gas;

[0048] When the controller 25 receives the detection value of the ash temperature sensor 5 greater than 500°C, the controller 25 will send an opening increase signal to the charging control valve 11 to increase the amount of cooling gas carbon dioxide introduced, thereby reducing the ash temperature;

[0049] (2) Steam secondary cooling: After primary cooling, the ash moves downward along the ash pipe 4 and contacts the cooling water. The cooling water at the cooling water surface absorbs the heat of the ash and evaporates. The steam generated by evaporation moves upward along the ash pipe 4 to perform secondary cooling on the ash. The temperature of the ash after secondary cooling is 200-300°C. The steam after heat exchange with the ash moves upward along the ash pipe 4 and enters the gasifier for use as a gasifying agent, thereby reducing the external supply of steam and the investment cost of steam. After the cooling water evaporates, low-temperature cooling water will be added, and there is no need to force the cooling water to circulate and cool it down, thus avoiding the blockage of the circulation pump and the heat exchanger during the circulation cooling process, thereby ensuring the smooth operation of the slag discharge device and the slag discharge efficiency.

[0050] (3) Cooling by cooling water three times: After the ash enters the cooling water, it is immersed in the cooling water. The cooling water can fully cool the ash and ensure the cooling effect. The cooling water cools it three times to below 150°C;

[0051] When the controller 25 receives a detection value greater than 150°C from the slag cooling tank temperature sensor 41, the controller 25 sends an opening increase signal to the water inlet control valve 8 to increase the amount of cooling water entering, thereby reducing the temperature of the cooling water in the slag cooling tank 1 and further reducing the temperature of the ash;

[0052] (4) Slag feeding and slag discharge of the slag discharge tank: After three coolings, the slag moves downward into the slag collecting tank 2 for temporary storage. When the slag in the slag discharge tank 3 is completely discharged, the second slag discharge valve 19 is closed, and the water injection valve 18 is opened to start water injection. When the detection value of the slag discharge liquid level sensor 17 reaches the preset value of the controller 25, the controller 25 sends a closing signal to the water injection valve 18, and the water injection valve 18 is closed. When the detection value of the slag discharge tank pressure sensor 16 is greater than the detection value of the cold slag tank pressure sensor 12, the controller 25 sends an opening signal to the pressure relief valve 15 to relieve the pressure of the slag discharge tank 3. When the detection value of the slag discharge tank pressure sensor 16 is equal to the cold slag tank pressure sensor 12, the pressure relief valve 15 is closed.

[0053] After adjusting the liquid level and pressure inside the slag discharge tank 3 according to the above steps, open the first slag discharge valve 14, and the high-pressure gas on the top of the slag discharge tank 3 moves upward into the slag collecting tank 2, and the ash at the bottom of the slag collecting tank 2 is disturbed and moves downward into the slag discharge tank 3; after the slag discharge tank 3 is fed with materials, close the first slag discharge valve 14, open the pressure relief valve 15, and after the detection value of the slag discharge tank pressure sensor 16 is equal to zero, open the second slag discharge valve 19 and the slag flushing valve 23, and the ash is smoothly taken away by the high-pressure induced water and flows along the slag discharge main pipe 20 to the slag storage device. During the slag feeding and discharge process of the slag discharge tank 3, the water balance valve 13 is always in the open state, and the water injected into the slag discharge tank 3 and the conveying water of the slag discharge main pipe 20 are both water discharged from the slag collecting tank 2 through the water balance valve 13, so that the water discharged from the slag collecting tank 2 is fully utilized to reduce the use of pure water resources.

[0054] The ash in the slag discharge main pipe 20 is transported by high-pressure water, so that the ash can be transported along the slag discharge main pipe 20 to the slag storage device at the end of the slag discharge main pipe 20. There is no need to limit the position of the slag storage device, which improves the flexibility of the equipment placement position. The high-pressure gas in the slag discharge tank 3 is discharged through the slag discharge main pipe 20, providing a certain pressure for the transportation of the ash, thereby ensuring the smooth transportation of the ash.

[0055] The water injected into the slag discharge tank 3 and the conveying water of the slag discharge main pipe 20 are both provided by the water discharged from the slag collection tank 2 through the water balance valve 13. The slag collection tank flushing valve 24 and the control valve 22 are opened at regular intervals to use the cooling water discharged from the cooling water pipe to flush the pipeline through which the slag water flows, so as to prevent the pipeline through which the slag water flows from being blocked. The flushing cycle is determined according to the actual working conditions of the system operation.

[0056] When the low liquid level sensor 30 detects that the cooling water level inside the cold slag tank 1 has reached the preset lower limit of the liquid level, the opening of the water inlet control valve 8 is increased, and the opening of the water balance valve 13 is decreased to replenish water to the tank body 26; when the high liquid level sensor 28 detects that the cooling water level has reached the preset upper limit of the liquid level, the opening of the water inlet control valve 8 is decreased, and the opening of the water balance valve 13 is increased, so that the cooling water level inside the tank body 26 is always maintained between the minimum liquid level and the maximum liquid level, so that the coal slag can be immersed in the cooling water, ensuring a good cooling effect.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A coal ash slag cooling and slag discharge system, characterized in that: It comprises a cold slag tank, a slag collecting tank and a slag discharging tank, the outlet of the ash pipe extends to the inner bottom of the cold slag tank, an ash temperature sensor is installed inside the top end of the ash pipe, a cooling water pipe is connected with the water inlet pipe of the cold slag tank, a water inlet control valve is installed on the water inlet pipe, an air charging pipe is connected to the upper part of the ash pipe inside the cold slag tank, the cooling air pipe is connected with the air charging pipe, an air charging control valve is installed on the air charging pipe, and a cold slag tank pressure sensor and a cold slag tank temperature sensor are installed on the top of the cold slag tank; The slag discharge port at the bottom of the cold slag tank is connected with the slag inlet at the top of the slag collecting tank, and a water balance valve is installed on the top of the slag collecting tank; the slag discharge port at the bottom of the slag collecting tank is connected with the slag inlet at the top of the slag discharge tank through a first slag discharge valve, a pressure relief valve and a slag discharge tank pressure sensor are installed on the top of the slag discharge tank, a slag discharge liquid level sensor is installed on the side of the slag discharge tank, a second slag discharge valve is installed at the bottom of the slag discharge tank, the second slag discharge valve is connected with the slag discharge main pipe, and a water injection valve is installed on the slag discharge tank above the second slag discharge valve.

2. A coal ash cooling and slag removal system according to claim 1, characterized in that: A connecting pipe is connected between the cooling water pipe and the water injection valve, and a control valve is installed on the connecting pipe.

3. A coal ash cooling and slag removal system according to claim 2, characterized in that: The connecting pipe at the outlet end of the control valve is connected to the slag discharge main pipe through a slag flushing valve, and the outlet end of the pressure relief valve is connected to the inlet of the slag discharge main pipe.

4. A coal ash slag cooling and slag removal system according to claim 3, characterized in that: The outlet end of the water balance valve is connected to the connecting pipe at the outlet end of the control valve, and the connecting pipe at the inlet end of the control valve is connected to the inlet end of the water balance valve through a slag collecting tank flushing valve.

5. A coal ash cooling and slag removal system according to claim 4, characterized in that: The ash temperature sensor, the cold slag tank temperature sensor, the cold slag tank pressure sensor, the slag discharge tank pressure sensor, and the slag discharge liquid level sensor are all electrically connected to the input end of the controller, and the output end of the controller is electrically connected to the water inlet control valve, the inflation control valve, and the pressure relief valve, respectively.

6. A coal ash cooling and slag removal system according to any one of claims 1 to 5, characterized in that: The cold slag tank includes a tank body, the ash pipe is vertically arranged in the middle of the tank body, the top end of the ash pipe extends to the outside of the top end of the tank body, and a channel is formed between the bottom end of the ash pipe and the bottom end of the tank body; a high liquid level sensor is arranged inside the tank body below the inflation pipe; a plurality of balancing holes are opened in a circumferential direction on the ash pipe below the high liquid level sensor, a low liquid level sensor is arranged inside the tank body below the balancing hole, and both the high liquid level sensor and the low liquid level sensor are electrically connected to the water inlet control valve and the water balancing valve; the water inlet pipe is connected to the side of the tank body, an annular water distribution pipe connected to the water inlet pipe is arranged on the outside of the ash pipe, and a plurality of water distribution holes are opened on the pipe wall of the annular water distribution pipe.

7. A coal ash slag cooling and slag removal system according to claim 6, characterized in that: The ash pipe comprises a straight tube heat exchange section, an expanded tube vaporization section and a straight tube slag discharge section which are sequentially connected from top to bottom. The inflation pipe is arranged in the straight tube heat exchange section, and the balance hole is opened in the upper part of the expanded tube vaporization section.

8. The coal ash cooling and slag removal system according to claim 6, characterized in that: An air distribution pipe is embedded and installed on the ash pipe above the high liquid level sensor, and the air charging pipe is connected with the ash pipe through the air distribution pipe; the air distribution pipe includes an annular sintered metal filter element and a tube body separately sleeved on the outside of the sintered metal filter element, the tube body is embedded and installed on the ash pipe, and the top and bottom ends of the tube body are respectively connected to the ash pipe through flanges, and the air charging pipe is connected with the inside of the tube body.

9. A coal ash cooling and slag removal system according to claim 6, characterized in that: A fire-resistant layer is provided on the inner wall of the ash pipe outside the tank body.

10. A coal ash cooling and slag removal system according to claim 6, characterized in that: A grate plate is fixed between the lower outer wall of the ash pipe and the inner wall of the tank body, and a manhole is provided on the side wall of the tank body.

11. A coal ash cooling and slag removal system according to claim 6, characterized in that: The inflation tube is a carbon dioxide inflation tube.

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