Device and method for recycling high-pressure flash steam

Abstract

The present invention belongs to the technical field of coal gasification, and specifically relates to a device and method for recycling high-pressure flash steam. The device of the present invention includes a stripping tower, a low-pressure conversion device, a heat recovery device, a compression device, an ammonia recovery tower, etc. By setting up the stripping tower, the flash steam is used to replace the steam to heat the low-temperature condensate generated by the high-pressure conversion device and the high-pressure non-conversion device, reducing steam consumption; the CO in the flash steam is converted into H2 through the low-pressure conversion device for recycling, 1.5 Mpa - 1.7 Mpa steam and 0.5 Mpa - 0.7 Mpa steam are by-produced through the heat recovery device, and the ammonia in the condensate generated by the heat recovery device is recovered by the ammonia recovery tower to obtain a 2% - 15% ammonia-containing aqueous solution for preparing water fertilizer. The present invention solves the problem of ammonium salt crystallization blockage in the top cooler of the hot water tower and the compression device, maintains the stable operation of the gasification device, avoids the situation of discharging the flash steam with abnormally high pressure to the flare, saves water resources and the effective gas in the flash steam, and also avoids the flare from going out.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal gasification, and specifically relates to a device and method for recycling high-pressure flash steam. Background Art

[0002] The efficient and clean utilization of coal has always been a major technical problem in the environmental protection and energy fields in China, and it is also one of the key technologies affecting the proportion structure of primary energy in China. Coal gasification is one of the main uses of coal in China at present, and it is the main way to convert primary energy into relatively clean secondary energy. The currently popular coal gasification technology is mainly entrained flow coal gasification, and the entrained flow technology is divided into two categories according to different feeding conditions: water coal slurry gasification and dry powder gasification. The water coal slurry gasification process is one of the main technologies for chemical products such as synthetic ammonia, methanol, and ethylene glycol in China. In the water coal slurry gasification process, the flash steam generated by the high-pressure flash tank enters the hot water tower, where the flash steam directly contacts and exchanges heat with fresh water, ash water, and shift condensate to cool down. The cooled flash steam enters the cooler at the top of the hot water tower, and the flash steam is indirectly cooled by circulating water. The flash steam cooled by the cooler at the top of the hot water tower enters the compression device to be pressurized and then reused. Since ammonium salts such as NH4HCO3, (NH4)2CO3, and ammonium carbamate are easily formed during the condensation and cooling process of the flash steam, the crystallization of these ammonium salts causes blockage of the cooler at the top of the hot water tower and the compression device, and the pressure of the flash steam generated by the high-pressure flash tank will increase, affecting the stable operation of the gasification device. In order to keep the gasification device running normally and stably, it is necessary to open the bypass valve of the safety valve on the connecting pipeline between the high-pressure flash tank and the hot water tower, and discharge the flash steam generated by the high-pressure flash tank to the flare for incineration. However, the flash steam contains a large amount of water and 30% - 35% of effective gas (the main components of the effective gas are H2 and CO). The discharge of a large amount of water to the flare causes waste of water resources and is also prone to causing the flare to go out. At the same time, the discharge of effective gas to the flare for incineration causes waste of resources. Summary of the Invention

[0003] In order to overcome the defects of the prior art, the present invention provides a device and method for recycling high-pressure flash steam, which can make the flash steam be fully utilized, avoid equipment blockage, ensure the temperature operation of the gasifier, and avoid the flare from going out, etc.

[0004] In order to achieve the above object, the technical solution of the present invention is as follows:

[0005] A device for recycling high-pressure flash steam, the device includes a hot water tower, a stripping tower, a low-pressure conversion device, a heat recovery device, a compression device, an ammonia recovery tower feed heat exchanger, an ammonia recovery tower, and an ammonia condenser. The inlet of the hot water tower is connected to the flash steam outlet of the high-pressure flash tank through pipeline a. The gas phase outlet of the hot water tower is connected to the inlet of the stripping tower through a pipeline. The gas phase outlet of the stripping tower is connected to the low-pressure conversion device through a pipeline. The stripping tower is also provided with a low-temperature condensate inlet, and the low-temperature condensate inlet is connected to the condensate outlets of the high-pressure conversion system and the high-pressure non-conversion system through a low-temperature condensate pipeline. The outlet of the low-pressure conversion device is connected to the heat recovery device through a pipeline. The gas phase outlet of the heat recovery device is connected to the compression device through a pipeline. The outlet of the compression device is connected to the downstream device through a pipeline. The condensate outlet of the heat recovery device is connected to the ammonia recovery tower through a pipeline and the ammonia recovery tower feed heat exchanger. The gas phase outlet of the ammonia recovery tower is connected to the inlet of the ammonia condenser through a pipeline. The outlet of the ammonia condenser is connected to the ammonia liquid storage tank through a pipeline.

[0006] Further, the low-pressure conversion device includes an inlet and outlet heat exchanger, a purification furnace, and a low-pressure conversion furnace. The purification furnace is filled with a filter agent, and the low-pressure conversion furnace is filled with a cobalt-molybdenum catalyst. The gas phase outlet of the stripping tower is connected to the inlet of the tube side of the inlet and outlet heat exchanger through a pipeline. The outlet of the tube side of the inlet and outlet heat exchanger is connected to the inlet of the purification furnace through a pipeline. The outlet of the purification furnace is connected to the inlet of the low-pressure conversion furnace through a pipeline. The outlet of the low-pressure conversion furnace is connected to the inlet of the shell side of the inlet and outlet heat exchanger through a pipeline.

[0007] Further, the heat recovery device includes a 1.5Mpa waste heat boiler device, a 0.5Mpa waste heat boiler device, and a desalted water heat exchange device. The inlet of the 1.5Mpa waste heat boiler device is connected to the outlet of the shell side of the inlet and outlet heat exchanger through a pipeline. The outlet of the 1.5Mpa waste heat boiler device is connected to the inlet of the 0.5Mpa waste heat boiler device through a pipeline. The inlet of the 0.5Mpa waste heat boiler device is connected to the inlet of the desalted water heat exchange device through a pipeline. The outlet of the desalted water heat exchange device is connected to the inlet of the compression device through a pipeline. The condensate outlets of the 1.5Mpa waste heat boiler device, the 0.5Mpa waste heat boiler device, and the desalted water heat exchange device are all connected to the inlet of the ammonia recovery tower through a pipeline and the ammonia recovery tower feed heat exchanger. A spray device a for cleaning the tube side is arranged in the desalted water heat exchange device, and the water inlet of the spray device a is connected to the washing water pipeline through a pipeline.

[0008] Further, trays or packing layers are arranged in the hot water tower and the stripping tower.

[0009] Further, a spray device b for cleaning the tube side is arranged in the ammonia condenser, and the water inlet of the spray device b is connected to the washing water pipeline through a pipeline.

[0010] A method for recycling high-pressure flash steam includes the following steps:

[0011] Step 1: The flash vapor generated by the high-pressure flash tank enters the hot water tower to directly contact and exchange heat with the low-temperature water for heat recovery. The low-temperature water is heated and flows out from the bottom of the hot water tower and is sent into the gasifier. At the same time, the ash in the flash vapor is washed and purified. After the flash vapor is cooled and purified, flash vapor a is obtained. The low-temperature water is one or more of the deammoniated water, ash water, and fresh water generated by the stripping tower;

[0012] Step 2: The flash vapor a generated in Step 1 enters the stripping tower and directly contacts and exchanges heat with the low-temperature condensate sent from the high-pressure conversion unit and the high-pressure non-conversion unit to heat and evaporate the ammonia in the low-temperature condensate. The deammoniated water obtained at the bottom of the stripping tower is sent to the hot water tower, and the process gas a obtained at the top of the stripping tower. The components of the process gas a include CO, H2, NH3, water vapor, H2S, and CO2;

[0013] Step 3: The process gas a generated in Step 2 enters the low-pressure conversion unit to react the CO in the process gas a with water vapor to be converted into H2 and CO2, obtaining process gas b. The components of the process gas b include H2, NH3, water vapor, H2S, and CO2;

[0014] Step 4: The process gas b generated in Step 3 enters the heat recovery device to recover the heat carried by the process gas b in the heat recovery device. The 1.5 Mpa - 1.7 Mpa steam is produced and sent to the 1.5 Mpa steam pipe network, and the 0.5 Mpa - 0.7 Mpa steam is produced and sent to the 0.5 Mpa steam pipe network. In the heat recovery device, the process gas b is cooled and washed to generate condensate a and process gas c. The components of the process gas c include H2, water vapor, H2S, and CO2;

[0015] Step 5: The process gas c flowing out of Step 4 enters the compression device, and the process gas c is boosted in pressure and sent to the downstream device;

[0016] Step 6: The condensate a generated in Step 4 enters the ammonia recovery tower after being preheated by the ammonia recovery tower feed heat exchanger. The condensate a is heated in the ammonia recovery tower. The process gas d is obtained at the top of the ammonia recovery tower. The process gas d enters the ammonia condenser to be condensed to obtain condensate b. The non-condensable gas flows out of the ammonia condenser to the flare. The condensate b enters the ammonia liquid storage tank, and the condensate b in the ammonia liquid storage tank is sent to the fertilizer and water preparation device. The condensate b is a mixed aqueous solution including components NH4(OH) and (NH4)2CO3.

[0017] Further, the temperature of the flash vapor is 165°C - 175°C, and the pressure is 0.7 Mpa - 0.9 Mpa; the temperature of the ash water and fresh water in Step 1 is 40°C - 120°C; the temperature of the flash vapor a is 163°C - 173°C.

[0018] Further, the concentration of ammonia in the low-temperature condensate is 3 g / L to 5 g / L, the temperature of the low-temperature condensate is 65°C to 80°C, the concentration of ammonia in the deammoniated water produced by the stripping tower is 0.1 g / L to 0.3 g / L, and the temperature of the deammoniated water produced by the stripping tower is 152°C to 158°C.

[0019] Further, the pressure of the process gas a in the low-pressure conversion device is 0.5 Mpa to 0.6 Mpa, the inlet temperature of the low-pressure conversion furnace is 170°C to 260°C, and the reaction temperature is 285°C to 380°C.

[0020] Further, the temperature of the process gas c is 30°C to 50°C, and the process gas c enters the compression device and is boosted to 2.0 Mpa to 6.0 Mpa and sent to the downstream device.

[0021] Further, the mass concentration of ammonia in the condensate b is 2% to 15%, the system pressure of the ammonia recovery tower is 0.05 Mpa to 0.10 Mpa, the temperature at the top of the ammonia recovery tower is 90°C to 120°C, and the temperature of the condensate b is 20 to 40°C. Beneficial effects

[0022] 1. By setting up a hot water tower and a stripping tower, the present invention recovers heat and washes and purifies the flash gas generated by the high-pressure flash tank in the hot water tower, so that the heat in the flash gas is recycled. In the stripping tower, the flash gas is used to replace steam to heat the low-temperature condensate generated by the high-pressure conversion device and the high-pressure non-conversion device, so that ammonia in the low-temperature condensate of the high-pressure conversion device and the high-pressure non-conversion device is evaporated, saving steam and thermal energy;

[0023] 2. By setting up a low-pressure conversion device, the present invention converts CO and water in the flash gas into H2 and CO2 in the low-pressure conversion device, and H2 is recycled and reused. At the same time, the potential heat in the flash gas is released. Then, through the heat recovery device set up, steam of 1.5 Mpa to 1.7 Mpa is produced and sent to the 1.5 Mpa steam pipe network, and steam of 0.5 Mpa to 0.7 Mpa is sent to the 0.5 Mpa steam pipe network, recovering the potential heat in the flash gas;

[0024] 3. By setting up an ammonia recovery tower and an ammonia condenser to heat the condensate a generated by the heat recovery device, the ammonia in the condensate a is evaporated, the ammonia in the condensate a is removed, and an ammonia-containing aqueous solution with a mass concentration of 2% to 15% is obtained. The ammonia-containing aqueous solution is sent to the water-fertilizer configuration device to configure water-fertilizer, and the ammonia-containing aqueous solution is effectively utilized;

[0025] 4. By setting up spray devices for cleaning the tube passes in both the demineralized water heat exchange device and the ammonia condenser, the present invention avoids the adhesion of crystalline ammonium salts on the tube pass walls in the tube passes of the demineralized water heat exchange device and the ammonia condenser, ensuring the long-term stable operation of the production device. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of the device of the present invention;

[0027] Figure 2 It is a process flow chart of the present invention;

[0028] In the figure, 1 - hot water tower; 2 - stripping tower; 3 - stripping tower bottom liquid transfer pump; 4 - feed and discharge heat exchanger; 5 - purification furnace; 6 - low-pressure conversion furnace; 7 - 1.5 Mpa waste heat boiler device; 8 - 0.5 Mpa waste heat boiler device; 9 - desalted water heat exchange device; 10 - compression device; 11 - ammonia recovery tower feed heat exchanger; 12 - ammonia recovery tower; 13 - ammonia condenser; 14 - ammonia liquid storage tank; 15 - reboiler; 16 - pipeline a; 17 - low-temperature water pipeline; 18 - low-temperature condensate pipeline; 19 - ammonia recovery tower bottom liquid transfer pump; 20 - washing water pipeline. Detailed Embodiments

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further elaborates on the present invention in combination with embodiments, but the present invention is not limited to the following examples. Embodiment 1

[0030] Refer to Figure 1 and Figure 2, in order to avoid waste of thermal energy, water resources and useful gas caused by discharging flash steam to the flare when the flash steam pressure in the high-pressure flash drum is abnormally high, and at the same time maintain the stable operation of the water coal slurry gasifier and avoid ammonium salt crystallization from clogging the top cooler of the hot water tower 1 and the compression device 10, a device for recycling high-pressure flash steam is provided. The device includes a hot water tower 1, a stripping tower 2, a low-pressure conversion device, a heat recovery device, a compression device 10, an ammonia recovery tower feed heat exchanger 11, an ammonia recovery tower 12, and an ammonia condenser 13. The low-pressure conversion device includes an inlet and outlet heat exchanger 4, a purification furnace 5, and a low-pressure conversion furnace 6. A filter agent is filled in the purification furnace 5, and the filter agent can adsorb and filter dust, arsenic, phosphorus, and chlorine. A cobalt-molybdenum catalyst is filled in the low-pressure conversion furnace 6. The heat recovery device includes a 1.5 Mpa waste heat boiler device 7, a 0.5 Mpa waste heat boiler device 8, and a desalted water heat exchange device 9. Gas-liquid separation devices are provided for the 1.5 Mpa waste heat boiler device 7, the 0.5 Mpa waste heat boiler device 8, and the desalted water heat exchange device 9. The inlet of the hot water tower 1 is connected to the flash steam outlet of the high-pressure flash drum through pipeline a. The gas phase outlet of the hot water tower 1 is connected to the inlet of the stripping tower 2 through a pipeline. The hot water tower 1 is also provided with a low-temperature water inlet connected to the low-temperature water pipeline 17. The bottom liquid outlet of the stripping tower 2 is connected to the hot water tower 1 through the stripping tower bottom liquid transfer pump 3 and a pipeline. The low-temperature condensate inlet provided by the stripping tower 2 is connected to the condensate outlet of the high-pressure conversion system and the condensate outlet of the high-pressure non-conversion system through the low-temperature condensate pipeline 18. The gas phase outlet of the stripping tower 2 is connected to the tube side inlet of the inlet and outlet heat exchanger 4 of the low-pressure conversion device through a pipeline. The tube side outlet of the inlet and outlet heat exchanger 4 is connected to the inlet of the purification furnace 5 through a pipeline. The outlet of the purification furnace 5 is connected to the inlet of the low-pressure conversion furnace 6 through a pipeline. The outlet of the low-pressure conversion furnace 6 is connected to the shell side inlet of the inlet and outlet heat exchanger 4 through a pipeline. The shell side outlet of the inlet and outlet heat exchanger 4 is connected to the inlet of the 1.5 Mpa waste heat boiler device 7 of the heat recovery device through a pipeline. The outlet of the 1.5 Mpa waste heat boiler device 7 is connected to the inlet of the 0.5 Mpa waste heat boiler device 8 through a pipeline. The outlet of the 0.5 Mpa waste heat boiler device 8 is connected to the inlet of the desalted water heat exchange device 9 through a pipeline. The outlet of the desalted water heat exchange device 9 is connected to the inlet of the compression device 10 through a pipeline. The outlet of the compression device 10 is connected to the downstream device through a pipeline. The hot water inlets of the 1.5 Mpa waste heat boiler device 7 and the 1.5 Mpa waste heat boiler device 7 are also connected to the 2.5 Mpa boiler water pipeline through a pipeline. The steam outlet of the 1.5 Mpa waste heat boiler device 7 is connected to the 1.5 Mpa steam network through a pipeline. The steam outlet of the 0.5 Mpa waste heat boiler device 8 is connected to the 0.5 Mpa steam network through a pipeline. The desalted water inlet of the desalted water heat exchange device 9 is connected to the 1.2 Mpa desalted water pipeline. The hot water outlet of the desalted water heat exchange device 9 is connected to the pipeline connecting to the inlet of the 2.5 Mpa boiler water feed pump; the condensate outlet of the 1.5 Mpa waste heat boiler device 7, 0.The condensate outlets of the 5 Mpa waste heat boiler device 8 and the condensate outlet of the demineralized water heat exchange device 9 are both connected to the inlet of the tube side of the ammonia recovery tower feed heat exchanger 11 through pipelines. The outlet of the tube side of the ammonia recovery tower feed heat exchanger 11 is connected to the ammonia recovery tower 12 through a pipeline. The gas phase outlet of the ammonia recovery tower 12 is connected to the inlet of the ammonia condenser 13 through a pipeline. The outlet of the ammonia condenser 13 is connected to the ammonia condenser 14 through a pipeline. The bottom liquid outlet of the ammonia recovery tower 12 is connected to the inlet of the shell side of the ammonia recovery tower feed heat exchanger 11 through the ammonia recovery tower bottom liquid transfer pump 19 and a pipeline. The outlet of the shell side of the ammonia recovery tower feed heat exchanger 11 is connected to the hot water tower 1 through a pipeline. A reboiler 15 is also provided at the bottom of the ammonia recovery tower 12. The tube side of the reboiler 15 is communicated with the ammonia recovery tower 12, and the shell side of the reboiler 15 is communicated with the 0.5 Mpa steam pipe network.

[0031] Trays are arranged in the hot water tower 1 and the stripping tower 2. The trays in the hot water tower 1 can enable the low-temperature water and the flash steam to fully contact and transfer heat; the trays in the stripping tower 2 can enable the flash steam a and the low-temperature condensate to fully contact and transfer heat; Spray devices for cleaning the tube side are arranged in both the demineralized water heat exchange device 9 and the ammonia condenser 13. The water inlets of the spray devices are connected to the washing water pipeline through pipelines.

[0032] A method for recycling high-pressure flash steam includes the following steps:

[0033] The flash steam generated by the high-pressure flash tank has a temperature of 165 °C and a pressure of 0.7 Mpa; the flash steam enters the hot water tower 1 and directly contacts and exchanges heat with the low-temperature water for heat recovery. At the same time, the ash in the flash steam is washed and purified. The low-temperature water is the deammoniated water generated by the stripping tower 2, the deammoniated water generated by the ammonia recovery tower 12, and the ash water. The ash water is at 40 °C. After being heated, the low-temperature water flows out from the bottom of the hot water tower 1 and is sent into the gasifier. After being cooled and purified, the flash steam is obtained as flash steam a, and the temperature of the flash steam a is 163 °C; the flash steam a enters the stripping tower 2 and directly contacts and exchanges heat with the low-temperature condensate sent from the high-pressure conversion device and the high-pressure non-conversion device, heating and evaporating the ammonia in the low-temperature condensate. Process gas a is obtained at the top of the stripping tower 2, and deammoniated water is obtained at the bottom of the stripping tower 2 and sent to the hot water tower 1. The temperature of the low-temperature condensate is 65 °C, the ammonia concentration in the low-temperature condensate is 5 g / L, the temperature of the deammoniated water is 152 °C, and the ammonia concentration in the deammoniated water is 0.3 g / L. The components of the process gas a include CO, H2, NH3, water vapor, H2S, and CO2;

[0034] Process gas a enters the tube side of the inlet and outlet heat exchanger 4 of the low-pressure conversion unit and is heated to 170°C. After being heated, process gas a enters the purification furnace 5, where dust and poisons are removed. The poisons are arsenic, phosphorus, and chlorine. The process gas a exiting the purification furnace 5 enters the low-pressure conversion furnace 6. The reaction temperature of the low-pressure conversion furnace 6 is controlled at 285°C, and the reaction pressure is 0.5 Mpa. In the low-pressure conversion furnace 6, CO reacts with steam to be converted into H2 and CO2, obtaining process gas b. Process gas b enters the shell side of the inlet and outlet heat exchanger 4, exchanges heat with process gas a to cool down, and then goes to the heat recovery device. The components of the process gas b include H2, NH3, steam, H2S, CO2, and unreacted CO;

[0035] Process gas b enters the 1.5 Mpa waste heat boiler device 7 of the heat recovery device, where it exchanges heat with 2.5 Mpa boiler water. Process gas b is cooled down to 201°C, and 1.5 Mpa steam is produced and sent to the 1.5 Mpa steam pipe network. After process gas b flows out of the 1.5 Mpa waste heat boiler device 7, it enters the 0.5 Mpa waste heat boiler device 8, where it exchanges heat with 2.5 Mpa boiler water. Process gas b is cooled down to 159°C, and 0.5 Mpa steam is produced and sent to the 0.5 Mpa steam pipe network. After process gas b flows out of the 0.5 Mpa waste heat boiler device 8, it enters the desalted water heat exchange device 9, where it exchanges heat with 1.2 Mpa desalted water. At the same time, washing water is introduced into the spraying device a in the desalted water heat exchange device 9 from the washing water pipeline. The washing water is water that has undergone desalination and deoxygenation treatment, so as to avoid ammonium salt crystallization in the tube side of the desalted water heat exchange device 9. The desalted water is heated and then sent to the inlet of the 2.5 Mpa boiler water feed pump. Process gas b flowing out of the desalted water heat exchange device 9 obtains process gas c. The temperature of process gas c is 30°C. Process gas c enters the compression device 10 and is boosted to 2.0 Mpa and sent to the downstream device.

[0036] The condensate generated by the 1.5 Mpa waste heat boiler device 7, the condensate generated by the 0.5 Mpa waste heat boiler device 8, and the condensate generated by the desalted water heat exchange device 9 are mixed to obtain condensate a. The condensate a enters the ammonia recovery tower feed heat exchanger 11 and is preheated before entering the ammonia recovery tower 12. The condensate a is heated in the ammonia recovery tower 12. The system pressure of the ammonia recovery tower 12 is controlled at 0.05 Mpa, and the temperature at the top of the ammonia recovery tower 12 is 90 °C. Process gas d is obtained at the top of the ammonia recovery tower 12. The process gas d enters the ammonia condenser 13 and is condensed to obtain condensate b. At the same time, washing water is introduced into the spraying device b in the ammonia condenser 13 from the washing water pipeline to prevent ammonium salt crystallization in the tube side of the ammonia condenser 13. The temperature of the condensate b is 20 °C, and the mass concentration of ammonia in the condensate b is 2%. The non-condensable gas flows out of the ammonia condenser 13 and goes to the flare. The condensate b enters the ammonia condenser 14, and the condensate b in the ammonia condenser 14 is sent to the fertilizer preparation device. The condensate b is a mixed aqueous solution including components NH4(OH) and (NH4)2CO3. Example 2

[0037] Refer to Figure 1 Figure 2, in order to avoid waste of thermal energy, water resources and useful gas caused by discharging flash steam to the flare when the flash steam pressure in the high-pressure flash tank is abnormally high, and at the same time maintain the stable operation of the water coal slurry gasifier and avoid ammonium salt crystallization from clogging the top cooler of the hot water tower 1 and the compression device 10, a device for recycling high-pressure flash steam is provided. The device includes a hot water tower 1, a stripping tower 2, a low-pressure conversion device, a heat recovery device, a compression device 10, an ammonia recovery tower feed heat exchanger 11, an ammonia recovery tower 12, and an ammonia condenser 13. The low-pressure conversion device includes an inlet and outlet heat exchanger 4, a purification furnace 5, and a low-pressure conversion furnace 6. A filter agent is filled in the purification furnace 5, and a cobalt-molybdenum catalyst is filled in the low-pressure conversion furnace 6. The heat recovery device includes a 1.5 Mpa waste heat boiler device 7, a 0.5 Mpa waste heat boiler device 8, and a desalted water heat exchange device 9. Gas-liquid separation devices are provided in the 1.5 Mpa waste heat boiler device 7, the 0.5 Mpa waste heat boiler device 8, and the desalted water heat exchange device 9. The inlet of the hot water tower 1 is connected to the flash steam outlet of the high-pressure flash tank through pipeline a. The gas-phase outlet of the hot water tower 1 is connected to the inlet of the stripping tower 2 through a pipeline. The hot water tower 1 is also provided with a low-temperature water inlet connected to the low-temperature water pipeline 17. The bottom liquid outlet of the stripping tower 2 is connected to the hot water tower 1 through the stripping tower bottom liquid transfer pump 3 and a pipeline. The low-temperature condensate inlet provided in the stripping tower 2 is connected to the condensate outlet of the high-pressure conversion system and the condensate outlet of the high-pressure non-conversion system through the low-temperature condensate pipeline 18. The gas-phase outlet of the stripping tower 2 is connected to the tube-side inlet of the inlet and outlet heat exchanger 4 of the low-pressure conversion device through a pipeline. The tube-side outlet of the inlet and outlet heat exchanger 4 is connected to the inlet of the purification furnace 5 through a pipeline. The outlet of the purification furnace 5 is connected to the inlet of the low-pressure conversion furnace 6 through a pipeline. The outlet of the low-pressure conversion furnace 6 is connected to the shell-side inlet of the inlet and outlet heat exchanger 4 through a pipeline. The shell-side outlet of the inlet and outlet heat exchanger 4 is connected to the inlet of the 1.5 Mpa waste heat boiler device 7 of the heat recovery device through a pipeline. The outlet of the 1.5 Mpa waste heat boiler device 7 is connected to the inlet of the 0.5 Mpa waste heat boiler device 8 through a pipeline. The outlet of the 0.5 Mpa waste heat boiler device 8 is connected to the inlet of the desalted water heat exchange device 9 through a pipeline. The outlet of the desalted water heat exchange device 9 is connected to the inlet of the compression device 10 through a pipeline. The outlet of the compression device 10 is connected to the downstream device through a pipeline. The hot water inlets of the 1.5 Mpa waste heat boiler device 7 and the 1.5 Mpa waste heat boiler device 7 are also connected to the 2.5 Mpa boiler water pipeline through a pipeline. The steam outlet of the 1.5 Mpa waste heat boiler device 7 is connected to the 1.5 Mpa steam network through a pipeline. The steam outlet of the 0.5 Mpa waste heat boiler device 8 is connected to the 0.5 Mpa steam network through a pipeline. The desalted water inlet of the desalted water heat exchange device 9 is connected to the 1.2 Mpa desalted water pipeline. The hot water outlet of the desalted water heat exchange device 9 is connected to the pipeline connecting to the inlet of the 2.5 Mpa boiler water feed pump; the condensate outlet of the 1.5 Mpa waste heat boiler device 7, 0.The condensate outlets of the 5 Mpa waste heat boiler device 8 and the condensate outlet of the demineralized water heat exchange device 9 are both connected to the inlet of the tube side of the ammonia recovery tower feed heat exchanger 11 through pipelines. The outlet of the tube side of the ammonia recovery tower feed heat exchanger 11 is connected to the ammonia recovery tower 12 through a pipeline. The gas phase outlet of the ammonia recovery tower 12 is connected to the inlet of the ammonia condenser 13 through a pipeline. The outlet of the ammonia condenser 13 is connected to the ammonia condenser 14 through a pipeline. The bottom liquid outlet of the ammonia recovery tower 12 is connected to the inlet of the shell side of the ammonia recovery tower feed heat exchanger 11 through the ammonia recovery tower bottom liquid transfer pump 19 and a pipeline. The outlet of the shell side of the ammonia recovery tower feed heat exchanger 11 is connected to the hot water tower 1 through a pipeline. A reboiler 15 is also provided at the bottom of the ammonia recovery tower 12. The tube side of the reboiler 15 is communicated with the ammonia recovery tower 12, and the shell side of the reboiler 15 is communicated with the 0.5 Mpa steam pipe network.

[0038] Packing layers are provided in the hot water tower 1 and the stripping tower 2. The packing layer in the hot water tower 1 can enable the low-temperature water and the flash steam to fully contact and transfer heat; the packing layer in the stripping tower 2 can enable the flash steam a and the low-temperature condensate to fully contact and transfer heat; Spraying devices for cleaning the tube side are provided in both the demineralized water heat exchange device 9 and the ammonia condenser 13. The water inlets of the spraying devices are connected to the washing water pipeline through pipelines.

[0039] A method for recycling high-pressure flash steam includes the following steps:

[0040] The flash steam generated by the high-pressure flash tank has a temperature of 170 °C and a pressure of 0.8 Mpa; the flash steam enters the hot water tower 1 and directly contacts and exchanges heat with the low-temperature water for heat recovery. At the same time, the ash in the flash steam is washed and purified. The low-temperature water is the deammoniated water generated by the stripping tower 2, the deammoniated water generated by the ammonia recovery tower 12, and fresh water. The temperature of the fresh water is 80 °C. After being heated, the low-temperature water flows out from the bottom of the hot water tower 1 and is sent into the gasifier. After being cooled and purified, the flash steam is obtained as flash steam a, and the temperature of the flash steam a is 168 °C; The flash steam a enters the stripping tower 2 and directly contacts and exchanges heat with the low-temperature condensate sent from the high-pressure conversion device and the high-pressure non-conversion device, heating and evaporating the ammonia in the low-temperature condensate. Process gas a is obtained at the top of the stripping tower 2, and deammoniated water is obtained at the bottom of the stripping tower 2 and sent to the hot water tower 1. The temperature of the low-temperature condensate is 72 °C, the ammonia concentration in the low-temperature condensate is 4 g / L, the temperature of the deammoniated water is 155 °C, and the ammonia concentration in the deammoniated water is 0.2 g / L. The components of the process gas a include CO, H2, NH3, water vapor, H2S, and CO2;

[0041] Process gas a enters the tube side of the feed and effluent heat exchanger 4 of the low-pressure conversion unit and is heated to 215°C. After being heated, process gas a enters the purification furnace 5, where dust and poisons are removed. The poisons are arsenic, phosphorus, and chlorine. The process gas leaving the purification furnace 5 enters the low-pressure conversion furnace 6. The reaction temperature of the low-pressure conversion furnace 6 is controlled at 340°C, and the reaction pressure is 0.55 Mpa. In the low-pressure conversion furnace 6, CO reacts with steam to be converted into H2 and CO2, obtaining process gas b. Process gas b enters the shell side of the feed and effluent heat exchanger 4, exchanges heat with process gas a to cool down, and then goes to the heat recovery device. The components of the process gas b include H2, NH3, steam, H2S, CO2, and unreacted CO;

[0042] Process gas b enters the 1.5 Mpa waste heat boiler device 7 of the heat recovery device, where it exchanges heat with 2.5 Mpa boiler water. Process gas b is cooled to 204°C, and 1.6 Mpa steam is produced and sent to the 1.5 Mpa steam pipe network. After process gas b flows out of the 1.5 Mpa waste heat boiler device 7, it enters the 0.5 Mpa waste heat boiler device 8, where it exchanges heat with 2.5 Mpa boiler water. Process gas b is cooled to 165°C, and 0.6 Mpa steam is produced and sent to the 0.5 Mpa steam pipe network. After process gas b flows out of the 0.5 Mpa waste heat boiler device 8, it enters the desalted water heat exchange device 9, where it exchanges heat with 1.2 Mpa desalted water. At the same time, washing water is introduced into the spraying device a in the desalted water heat exchange device 9 from the washing water pipeline. The washing water is water that has undergone desalination and deoxygenation treatment to prevent ammonium salt crystallization in the tube side of the desalted water heat exchange device 9. The desalted water is heated and sent to the inlet of the 2.5 Mpa boiler water feed pump. Process gas b flows out of the desalted water heat exchange device 9 to obtain process gas c. The temperature of process gas c is 40°C. Process gas c enters the compression device 10 and is pressurized to 4.0 Mpa and sent to the downstream device.

[0043] The condensate generated by the 1.5 Mpa waste heat boiler device 7, the condensate generated by the 1.5 Mpa waste heat boiler device 7, and the condensate generated by the desalted water heat exchange device 9 are mixed to obtain condensate a. The condensate a enters the ammonia recovery tower feed heat exchanger 11 and is preheated before entering the ammonia recovery tower 12. The condensate a is heated in the ammonia recovery tower 12. The system pressure of the ammonia recovery tower 12 is controlled at 0.75 Mpa, and the temperature at the top of the ammonia recovery tower 12 is 105 °C. Process gas d is obtained at the top of the ammonia recovery tower 12. The process gas d enters the ammonia condenser 13 and is condensed to obtain condensate b. At the same time, washing water is introduced into the spraying device b in the ammonia condenser 13 from the washing water pipeline to prevent ammonium salt crystallization in the tube side of the ammonia condenser 13. The temperature of the condensate b is 30 °C, and the mass concentration of ammonia in the condensate b is 10%. The non-condensable gas flows out of the ammonia condenser 13 and goes to the flare; the condensate b enters the ammonia condenser 14, and the condensate b in the ammonia condenser 14 is sent to the fertilizer preparation device. The condensate b is a mixed aqueous solution including components NH4(OH) and (NH4)2CO3. Example 3

[0044] Refer to Figure 1 Figure 2, in order to avoid waste of thermal energy, water resources and useful gas caused by discharging flash steam to the flare when the flash steam pressure in the high-pressure flash drum is abnormally high, and at the same time maintain the stable operation of the water coal slurry gasifier and avoid ammonium salt crystallization from clogging the top cooler of the hot water tower 1 and the compression device 10, a device for recycling high-pressure flash steam is provided. The device includes a hot water tower 1, a stripping tower 2, a low-pressure conversion device, a heat recovery device, a compression device 10, an ammonia recovery tower feed heat exchanger 11, an ammonia recovery tower 12, and an ammonia condenser 13. The low-pressure conversion device includes an inlet and outlet heat exchanger 4, a purification furnace 5, and a low-pressure conversion furnace 6. A filter agent is filled in the purification furnace 5, and a cobalt-molybdenum catalyst is filled in the low-pressure conversion furnace 6. The heat recovery device includes a 1.5 Mpa waste heat boiler device 7, a 0.5 Mpa waste heat boiler device 8, and a desalted water heat exchange device 9. Gas-liquid separation devices are provided for the 1.5 Mpa waste heat boiler device 7, the 0.5 Mpa waste heat boiler device 8, and the desalted water heat exchange device 9. The inlet of the hot water tower 1 is connected to the flash steam outlet of the high-pressure flash drum through pipeline a. The gas-phase outlet of the hot water tower 1 is connected to the inlet of the stripping tower 2 through a pipeline. The hot water tower 1 is also provided with a low-temperature water inlet connected to a low-temperature water pipeline 17. The bottom liquid outlet of the stripping tower 2 is connected to the hot water tower 1 through a stripping tower bottom liquid transfer pump 3 and a pipeline. The low-temperature condensate inlet provided in the stripping tower 2 is connected to the condensate outlet of the high-pressure conversion system and the condensate outlet of the high-pressure non-conversion system through a low-temperature condensate pipeline 18. The gas-phase outlet of the stripping tower 2 is connected to the tube-side inlet of the inlet and outlet heat exchanger 4 of the low-pressure conversion device through a pipeline. The tube-side outlet of the inlet and outlet heat exchanger 4 is connected to the inlet of the purification furnace 5 through a pipeline. The outlet of the purification furnace 5 is connected to the inlet of the low-pressure conversion furnace 6 through a pipeline. The outlet of the low-pressure conversion furnace 6 is connected to the shell-side inlet of the inlet and outlet heat exchanger 4 through a pipeline. The shell-side outlet of the inlet and outlet heat exchanger 4 is connected to the inlet of the 1.5 Mpa waste heat boiler device 7 of the heat recovery device through a pipeline. The outlet of the 1.5 Mpa waste heat boiler device 7 is connected to the inlet of the 0.5 Mpa waste heat boiler device 8 through a pipeline. The outlet of the 0.5 Mpa waste heat boiler device 8 is connected to the inlet of the desalted water heat exchange device 9 through a pipeline. The outlet of the desalted water heat exchange device 9 is connected to the inlet of the compression device 10 through a pipeline. The outlet of the compression device 10 is connected to a downstream device through a pipeline. The hot water inlets of the 1.5 Mpa waste heat boiler device 7 and the 1.5 Mpa waste heat boiler device 7 are also connected to a 2.5 Mpa boiler water pipeline through a pipeline. The steam outlet of the 1.5 Mpa waste heat boiler device 7 is connected to a 1.5 Mpa steam network through a pipeline. The steam outlet of the 0.5 Mpa waste heat boiler device 8 is connected to a 0.5 Mpa steam network through a pipeline. The desalted water inlet of the desalted water heat exchange device 9 is connected to a 1.2 Mpa desalted water pipeline. The hot water outlet of the desalted water heat exchange device 9 is connected to a pipeline connected to the inlet of a 2.5 Mpa boiler water feed pump. The condensate outlet of the 1.5 Mpa waste heat boiler device 7, 0.The condensate outlets of the 5 Mpa waste heat boiler device 8 and the condensate outlet of the demineralized water heat exchange device 9 are both connected to the inlet of the tube side of the ammonia recovery tower feed heat exchanger 11 through pipelines. The outlet of the tube side of the ammonia recovery tower feed heat exchanger 11 is connected to the ammonia recovery tower 12 through a pipeline. The gas phase outlet of the ammonia recovery tower 12 is connected to the inlet of the ammonia condenser 13 through a pipeline. The outlet of the ammonia condenser 13 is connected to the ammonia condenser 14 through a pipeline. The bottom liquid outlet of the ammonia recovery tower 12 is connected to the inlet of the shell side of the ammonia recovery tower feed heat exchanger 11 through the ammonia recovery tower bottom liquid transfer pump 19 and a pipeline. The outlet of the shell side of the ammonia recovery tower feed heat exchanger 11 is connected to the hot water tower 1 through a pipeline. A reboiler 15 is also provided at the bottom of the ammonia recovery tower 12. The tube side of the reboiler 15 is communicated with the ammonia recovery tower 12, and the shell side of the reboiler 15 is communicated with the 0.5 Mpa steam pipe network.

[0045] A packing layer is arranged in the hot water tower 1, and trays are arranged in the stripping tower 2. The packing layer in the hot water tower 1 can enable the low-temperature water and the flash steam to fully contact and transfer heat; the trays in the stripping tower 2 can enable the flash steam a and the low-temperature condensate to fully contact and transfer heat; spray devices for cleaning the tube side are arranged in both the demineralized water heat exchange device 9 and the ammonia condenser 13, and the water inlets of the spray devices are connected to the washing water pipeline through pipelines.

[0046] A method for recycling high-pressure flash steam includes the following steps:

[0047] The flash steam generated by the high-pressure flash tank has a temperature of 175 °C and a pressure of 0.9 Mpa; the flash steam enters the hot water tower 1 to directly contact and exchange heat with the low-temperature water for heat recovery. At the same time, the ash in the flash steam is washed and purified. The low-temperature water is the deammoniated water generated by the stripping tower 2, the deammoniated water generated by the ammonia recovery tower 12, the ash water, and the fresh water. The temperature of the ash water and the fresh water is 120 °C. After being heated, the low-temperature water flows out from the bottom of the hot water tower 1 and is sent into the gasifier. After being cooled and purified, the flash steam obtains flash steam a, and the temperature of the flash steam a is 173 °C; the flash steam a enters the stripping tower 2 and directly contacts and exchanges heat with the low-temperature condensate sent from the high-pressure conversion device and the high-pressure non-conversion device, heating and evaporating the ammonia in the low-temperature condensate. Process gas a is obtained at the top of the stripping tower 2, and deammoniated water is obtained at the bottom of the stripping tower 2 and sent to the hot water tower 1. The temperature of the low-temperature condensate is 80 °C, the ammonia concentration in the low-temperature condensate is 3 g / L, the temperature of the deammoniated water is 158 °C, and the ammonia concentration in the deammoniated water is 0.1 g / L. The components of the process gas a include CO, H2, NH3, water vapor, H2S, and CO2;

[0048] Process gas a enters the tube side of the inlet and outlet heat exchanger 4 of the low-pressure conversion unit and is heated to 260 °C. After being heated, process gas a enters the purification furnace 5, where dust and poisons are removed. The poisons are arsenic, phosphorus, and chlorine. The process gas leaving the purification furnace 5 enters the low-pressure conversion furnace 6. The reaction temperature of the low-pressure conversion furnace 6 is controlled at 380 °C, and the reaction pressure is 0.6 Mpa. In the low-pressure conversion furnace 6, CO reacts with steam to be converted into H2 and CO2, obtaining process gas b. Process gas b enters the shell side of the inlet and outlet heat exchanger 4, exchanges heat with process gas a to reduce the temperature, and then goes to the heat recovery device. The components of the process gas b include H2, NH3, steam, H2S, CO2, and unreacted CO;

[0049] Process gas b enters the 1.5 Mpa waste heat boiler device 7 of the heat recovery device, exchanges heat with 2.5 Mpa boiler water in the 1.5 Mpa waste heat boiler device 7. Process gas b is cooled to 207 °C, and 1.7 Mpa steam is produced and sent to the 1.5 Mpa steam pipe network. After process gas b flows out of the 1.5 Mpa waste heat boiler device 7, it enters the 0.5 Mpa waste heat boiler device 8, exchanges heat with 2.5 Mpa boiler water in the 0.5 Mpa waste heat boiler device 8. Process gas b is cooled to 170 °C, and 0.7 Mpa steam is produced and sent to the 0.5 Mpa steam pipe network. After process gas b flows out of the 0.5 Mpa waste heat boiler device 8, it enters the desalted water heat exchange device 9, exchanges heat with 1.2 Mpa desalted water in the desalted water heat exchange device 9. At the same time, washing water is introduced into the spraying device a in the desalted water heat exchange device 9 from the washing water pipeline. The washing water is water that has undergone desalination and deoxygenation treatment, so as to avoid ammonium salt crystallization in the tube side of the desalted water heat exchange device 9. The desalted water is heated and then sent to the inlet of the 2.5 Mpa boiler water feed pump. Process gas b flowing out of the desalted water heat exchange device 9 obtains process gas c. The temperature of process gas c is 50 °C. Process gas c enters the compression device 10, and is pressurized to 6.0 Mpa and sent to the downstream device.

[0050] The condensate generated by the 1.5 Mpa waste heat boiler device 7, the condensate generated by the 0.5 Mpa waste heat boiler device 8, and the condensate generated by the desalted water heat exchange device 9 are mixed to obtain condensate a. The condensate a enters the ammonia recovery tower feed heat exchanger 11 and is preheated before entering the ammonia recovery tower 12. The condensate a is heated in the ammonia recovery tower 12. The system pressure of the ammonia recovery tower 12 is controlled at 0.1 Mpa, and the temperature at the top of the ammonia recovery tower 12 is 120 °C. Process gas d is obtained at the top of the ammonia recovery tower 12. The process gas d enters the ammonia condenser 13 and is condensed to obtain condensate b. Meanwhile, washing water is introduced into the spraying device b in the ammonia condenser 13 from the washing water pipeline to prevent ammonium salt crystallization in the tube side of the ammonia condenser 13. The temperature of the condensate b is 40 °C, and the mass concentration of ammonia in the condensate b is 15%. The non-condensable gas flows out of the ammonia condenser 13 and goes to the flare; the condensate b enters the ammonia condenser 14, and the condensate b in the ammonia condenser 14 is sent to the ammonia-water fertilizer preparation device. The condensate b is a mixed aqueous solution including components NH4(OH) and (NH4)2CO3.

[0051] The working principle of the present invention is as follows: By setting up a hot water tower and a stripping tower, the flash gas generated by the high-pressure flash tank is subjected to heat recovery and washing purification in the hot water tower, so that the heat in the flash gas is recycled. In the stripping tower, the flash gas is used to replace steam to heat the low-temperature condensate generated by the high-pressure conversion device and the high-pressure non-conversion device, so that ammonia in the low-temperature condensate of the high-pressure conversion device and the high-pressure non-conversion device is distilled out, saving steam and thermal energy; the present invention also sets up a low-pressure conversion device, so that CO and water in the flash gas are converted into H2 and CO2 in the low-pressure conversion device, and H2 is recycled and reused. At the same time, the potential heat in the flash gas is released. Then, through the heat recovery device set up, steam of 1.5 Mpa to 1.7 Mpa is produced and sent to the 1.5 Mpa steam pipe network, and steam of 0.5 Mpa to 0.7 Mpa is produced and sent to the 0.5 Mpa steam pipe network, recovering the potential heat in the flash gas; spraying devices for cleaning the tube side are arranged in both the desalted water heat exchange device and the ammonia condenser, avoiding the adhesion of crystalline ammonium salts on the tube wall of the tube side of the desalted water heat exchange device and the ammonia condenser, ensuring the long-term stable operation of the production device. By setting up an ammonia recovery tower and an ammonia condenser, the condensate a generated by the heat recovery device is heated, so that ammonia in the condensate a evaporates, extracting ammonia from the condensate a to obtain an ammonia-containing aqueous solution with a mass concentration of 2% to 15%. The ammonia-containing aqueous solution is sent to the ammonia-water fertilizer preparation device to prepare ammonia-water fertilizer, and the ammonia-containing aqueous solution is effectively utilized.

[0052] Modifications and variations to this creation by those familiar with the present invention fall within the scope of the patent of the present invention, not limited to those described in the embodiments.

Claims

1. An apparatus for recycling high-pressure flash steam, characterized in that: The device includes a hot water tower, a stripping tower, a low-pressure conversion device, a heat recovery device, a compression device, a feed heat exchanger for the ammonia recovery tower, an ammonia recovery tower, and an ammonia condenser. The inlet of the hot water tower is connected to the flash gas outlet of the high-pressure flash tank through pipeline a. The gas-phase outlet of the hot water tower is connected to the inlet of the stripping tower through a pipeline. The gas-phase outlet of the stripping tower is connected to the low-pressure conversion device through a pipeline. The stripping tower is also provided with a low-temperature condensate inlet, and the low-temperature condensate inlet is connected to the condensate outlets of the high-pressure conversion system and the high-pressure non-conversion system through a low-temperature condensate pipeline. The outlet of the low-pressure conversion device is connected to the heat recovery device through a pipeline. The gas-phase outlet of the heat recovery device is connected to the compression device through a pipeline. The outlet of the compression device is connected to the downstream device through a pipeline. The condensate outlet of the heat recovery device is connected to the ammonia recovery tower through a pipeline and the feed heat exchanger for the ammonia recovery tower. The gas-phase outlet of the ammonia recovery tower is connected to the inlet of the ammonia condenser through a pipeline. The outlet of the ammonia condenser is connected to the ammonia liquid storage tank through a pipeline. Trays or packing layers are arranged in the hot water tower and the stripping tower. A spraying device b for cleaning the tube side is arranged in the ammonia condenser, and the water inlet of the spraying device b is connected to the washing water pipeline through a pipeline.

2. The apparatus for recycling high-pressure flash steam according to claim 1, characterized in that: The low-pressure conversion device includes an inlet / outlet heat exchanger, a purification furnace, and a low-pressure conversion furnace. A filter agent is filled in the purification furnace, and a cobalt-molybdenum catalyst is filled in the low-pressure conversion furnace. The gas-phase outlet of the stripping tower is connected to the inlet of the tube side of the inlet / outlet heat exchanger through a pipeline. The outlet of the tube side of the inlet / outlet heat exchanger is connected to the inlet of the purification furnace through a pipeline. The outlet of the purification furnace is connected to the inlet of the low-pressure conversion furnace through a pipeline. The outlet of the low-pressure conversion furnace is connected to the inlet of the shell side of the inlet / outlet heat exchanger through a pipeline.

3. The apparatus for recycling high-pressure flash steam according to claim 1, characterized in that: The heat recovery device includes a 1.5 Mpa waste heat boiler device, a 0.5 Mpa waste heat boiler device, and a desalted water heat exchange device. The inlet of the 1.5 Mpa waste heat boiler device is connected to the outlet of the shell side of the inlet / outlet heat exchanger through a pipeline. The outlet of the 1.5 Mpa waste heat boiler device is connected to the inlet of the 0.5 Mpa waste heat boiler device through a pipeline. The inlet of the 0.5 Mpa waste heat boiler device is connected to the inlet of the desalted water heat exchange device through a pipeline. The outlet of the desalted water heat exchange device is connected to the inlet of the compression device through a pipeline. The condensate outlets of the 1.5 Mpa waste heat boiler device, the 0.5 Mpa waste heat boiler device, and the desalted water heat exchange device are all connected to the inlet of the ammonia recovery tower through a pipeline and the feed heat exchanger for the ammonia recovery tower. A spraying device a for cleaning the tube side is arranged in the desalted water heat exchange device, and the water inlet of the spraying device a is connected to the washing water pipeline through a pipeline.

4. A method for recycling high-pressure flash steam, characterized in that: It includes the following steps: Step 1: The flash gas generated by the high-pressure flash tank enters the hot water tower and directly contacts and exchanges heat with low-temperature water for heat recovery. After the low-temperature water is heated, it flows out from the bottom of the hot water tower and is sent into the gasifier. At the same time, the ash in the flash gas is washed and purified. After the flash gas is cooled and purified, flash gas a is obtained. The low-temperature water is one or more of the deammoniated water generated by the stripping tower, the deammoniated water generated by the ammonia recovery tower, the ash water, and the fresh water. Step 2: The flash vapor a generated in Step 1 enters the stripping column and directly contacts and exchanges heat with the low-temperature condensate sent from the high-pressure conversion unit and the high-pressure non-conversion unit, heating and evaporating the ammonia in the low-temperature condensate. The deammoniated water obtained at the bottom of the stripping column is sent to the hot water tower, and the process gas a obtained at the top of the stripping column. The components of the process gas a include CO, H2, NH3, water vapor, H2S, and CO2; Step 3: The process gas a generated in Step 2 enters the low-pressure conversion unit, reacting the CO in the process gas a with water vapor to be converted into H2 and CO2, obtaining the process gas b. The components of the process gas b include H2, NH3, water vapor, H2S, CO2, and unreacted CO; Step 4: The process gas b generated in Step 3 enters the heat recovery device, recovering the heat carried by the process gas b in the heat recovery device, producing 1.5 Mpa - 1.7 Mpa steam and sending it to the 1.5 Mpa steam pipe network, producing 0.5 Mpa - 0.7 Mpa steam and sending it to the 0.5 Mpa steam pipe network. In the heat recovery device, the process gas b is cooled and washed, generating condensate a and process gas c. The components of the process gas c include H2, H2S, CO2, and unreacted CO; Step 5: The process gas c flowing out of Step 4 enters the compression device, and after being pressurized, it is sent to the downstream device; Step 6: The condensate a generated in Step 4 enters the ammonia recovery column after being preheated by the ammonia recovery column feed heat exchanger. The condensate a is heated in the ammonia recovery column. The process gas d is obtained at the top of the ammonia recovery column. The process gas d enters the ammonia condenser and is condensed to obtain condensate b. The non-condensable gas flows out of the ammonia condenser to the flare. The condensate b enters the ammonia liquid storage tank, and the condensate b in the ammonia liquid storage tank is sent to the fertilizer and water preparation device. The condensate b is a mixed aqueous solution including components NH4(OH) and (NH4)2CO3.

5. The method for recycling high-pressure flash steam according to claim 4, characterized in that: The temperature of the flash vapor is 165°C - 175°C, and the pressure is 0.7 Mpa - 0.9 Mpa; the temperature of the ash water and fresh water in Step 1 is 40°C - 120°C; the temperature of the flash vapor a is 163°C - 173°C.

6. The method for recycling high-pressure flash steam according to claim 4, characterized in that: The ammonia concentration in the low-temperature condensate is 3 g / L - 5 g / L, the temperature of the low-temperature condensate is 65°C - 80°C, the ammonia concentration in the deammoniated water generated by the stripping column is 0.1 g / L - 0.3 g / L, and the temperature of the deammoniated water generated by the stripping column is 152°C - 158°C.

7. The method for recycling high-pressure flash steam according to claim 4, characterized in that: The reaction pressure of the process gas a in the low-pressure conversion unit is 0.5 Mpa - 0.6 Mpa, and the reaction temperature is 285°C - 380°C.

8. The method for recycling high-pressure flash steam according to claim 4, characterized in that: The temperature of the process gas c is 30°C - 50°C, and the process gas c enters the compression device and is pressurized to 2.0 Mpa - 6.0 Mpa and sent to the downstream device.

9. The method for recycling high-pressure flash steam according to claim 4, characterized in that: The mass concentration of ammonia in the condensate b is 2% - 15%, the system pressure of the ammonia recovery column is 0.05 Mpa - 0.10 Mpa, the temperature at the top of the ammonia recovery column is 90°C - 120°C, and the temperature of the condensate b is 20 - 40°C.

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