Device for cooling gasified sealing water and pre-cooling shift gas by utilizing low first washing cold capacity
By recovering the exhaust gas cooling capacity and using a cold sealed water precooler to reduce the cold sealed water temperature, the problems of high temperature of the gasified cold sealed water and high water and ammonia content in the converted gas are solved, and the water consumption and treatment load are reduced, thus reducing methanol consumption and ammonia enrichment.
Patent Information
- Application Number
- CN202421837147.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-31
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-07-31
AI Technical Summary
The high temperature of the cold sealed water from gasification and the high content of water and ammonia in the gasification gas changes, which affects the operation of the low-grade washing device, increases the water consumption and treatment load, resulting in increased methanol consumption and ammonia enrichment.
By recovering the gas phase cooling capacity of the exhaust gas scrubber, the cold sealed water precooler is used to reduce the temperature of the cold sealed water, and heat exchange and cooling are carried out through the raw gas precooler and the raw gas cooler to reduce the water and ammonia content in the changed gas.
The cold sealed water temperature is reduced, the washing effect is improved, the water consumption and treatment load are reduced, the consumption of sprayed methanol and the steam consumption of methanol water separation tower are reduced, and the ammonia content and environmental pressure are reduced.
Smart Images
Figure CN222855055U_ABST
Abstract
Description
Technical Field
[0001] The utility model designs a gas purification technology for a coal chemical plant, and particularly relates to a device for cooling gasification sealing water and converting gas precooling by utilizing low methyl alcohol washing cooling capacity. Background Art
[0002] The temperature of the cold sealing water from gasification is affected by the temperature of the circulating water, and the temperature is always around 30°C. It enters the ammonia washing tower to wash the ammonia in the conversion gas. The ammonia washing effect becomes worse and the flow of cold sealing water needs to be increased, which increases the water consumption and the water content in the conversion gas. The risk of methanol-water content increase in the long-term operation of the low-methane washing increases, and the processing load of the methanol-water separation tower increases, which also leads to the enrichment of ammonia content in the low-temperature methanol washing system. The conversion gas is sent to the low-methane washing at a temperature of 30°C and mixed with spray methanol, and then cooled to -13°C through the raw gas cooler and enters the raw gas-water separator. The gas phase enters the washing tower, and the liquid phase enters the methanol-water separation tower, which increases the consumption of spray methanol, and also increases the steam consumption of the methanol-water separation tower and the risk of tower equipment corrosion. Summary of the invention
[0003] The utility model aims to solve or alleviate the influence of high temperature of cold sealing water, conversion gas-water and high ammonia content on the operation of low-level washing device by reasonably distributing and utilizing the cold capacity of low-level washing.
[0004] The technical scheme adopted by the utility model is to recycle the gas phase coldness of the tail gas washing tower and use it to cool the cold sealing water of the cold sealing water precooler pipe to 15-20℃, and then enter the ammonia washing tower to wash the ammonia in the conversion gas. The conversion gas enters the raw gas precooler pipe and is cooled to 4-8℃ by heat exchange from the liquid nitrogen cold synthesis gas pipe, and the separated water is sent to the conversion stripping tower for treatment. The condensed acidic aqueous solution enters the raw gas water-gas separator, the liquid phase is sent to the stripping tower through the stripping tower pipeline valve, and the gas phase enters the raw gas cooler.
[0005] A device for precooling gasified seal water and converting gas by using low-methane washing cooling capacity, wherein a cold seal water precooler is connected to the upper part of an ammonia washing tower via a cold seal water regulating valve; the top outlet of the ammonia washing tower is connected to the inlet of a raw gas precooler, the outlet of the raw gas precooler is connected to the inlet of a raw gas-water separator, and the liquid phase outlet of the raw gas-water separator is connected to a destripping tower pipeline via a destripping tower pipeline valve.
[0006] The gas phase outlet of the raw gas-water separator is connected to the inlet of the raw gas cooler, and a methanol spray pipeline is arranged on the connected pipeline, and a spray methanol regulating valve is arranged on the methanol spray pipeline.
[0007] The raw gas cooler is provided with an exhaust gas inlet pipeline, a purified gas / liquid nitrogen washed synthesis gas inlet pipeline, and a CO2 gas inlet pipeline.
[0008] The purified gas or cold synthesis gas inlet pipeline is provided with a raw gas cooler regulating valve; the purified gas or cold synthesis gas inlet pipeline is also connected to the shell side inlet of the raw gas-water separator, and the connecting pipeline is provided with a raw gas precooler regulating valve.
[0009] The outlet of the raw gas cooler is connected to the raw gas methanol water separator, and the top outlet of the raw gas methanol water separator is connected to the tail gas washing tower through a pipeline; the top outlet of the raw gas cooler is connected to the tail gas washing tower through a pipeline.
[0010] The tail gas scrubber is connected to the cold sealing water precooler via a pipeline.
[0011] The gas phase temperature of the raw gas water-gas separator is reduced to ensure the absorption effect of the methanol washing tower; the saturated water and spray methanol mixture in the conversion gas enters the raw gas cooler and condenses in the raw gas methanol-water separator, and the methanol-water ratio is reduced from 0.15% to about 0.09%, reducing the amount of spray methanol and the power consumption of the circulating methanol pump; after the amount of saturated water and spray methanol mixture sent to the methanol-water separation tower is reduced, the steam consumption of the regeneration tower 0.5MPa is reduced from 5200kg / h to 4500kg / h, and the steam consumption of the water separation tower 1.5MPa is reduced from 3500kg / h to 3000kg / h; at the same time, the tail gas cooling capacity is recovered, the ammonia content of the conversion gas inlet is reduced, and the ammonia content in the reflux tank at the top of the distillation tower is reduced from 1200mg / L to 700mg / L, reducing the waste of methanol caused by the low ammonia content of the methanol washing discharge and the environmental pressure caused by the increase of ammonia nitrogen content in the sulfur recovery tail gas. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 The utility model is a diagram of a device for cooling gasification seal water and precooling conversion gas using low methanol washing cooling capacity, in which: cold seal water from gasification 1, raw gas precooler 2, degassing tower pipeline 3, degassing tower pipeline valve 4, raw gas-water separator 5, raw gas precooler regulating valve 6, spray methanol regulating valve 7, raw gas cooler regulating valve 8, raw gas cooler 9, raw gas methanol-water separator 10, tail gas washing tower 11, cold seal water precooler 12, ammonia washing tower 13, cold seal water inlet ammonia washing tower temperature display instrument 14, raw gas precooler outlet temperature display remote transmission instrument 15, cold seal water precooler sub-line regulating valve 16, and ammonia in conversion gas 17. DETAILED DESCRIPTION
[0013] Example 1
[0014] A device for cooling gasified seal water and converting gas precooling by using low-methane washing cooling capacity, wherein a cold seal water precooler 12 is connected to the upper part of an ammonia washing tower 13 via a cold seal water regulating valve 1; the top outlet of the ammonia washing tower 13 is connected to the inlet of a raw gas precooler 2, the outlet of the raw gas precooler 2 is connected to the inlet of a raw gas-water separator 5, and the liquid phase outlet of the raw gas-water separator 5 is connected to a destripping tower pipeline 3 via a destripping tower pipeline valve 4.
[0015] The gas phase outlet of the raw gas-water separator 5 is connected to the inlet of the raw gas cooler 9 , and a methanol spray pipeline 20 is provided on the connected pipeline, and a spray methanol regulating valve 7 is provided on the methanol spray pipeline 20 .
[0016] The raw gas cooler 9 is provided with an exhaust gas inlet pipeline 17 , a purified gas / liquid nitrogen washed synthesis gas inlet pipeline 18 , and a CO2 gas inlet pipeline 19 .
[0017] The purified gas or cold synthesis gas inlet pipeline 18 is provided with a raw gas cooler regulating valve 8; the purified gas or cold synthesis gas inlet pipeline 18 is also connected to the shell side inlet of the raw gas-water separator 5, and the connecting pipeline is provided with a raw gas precooler regulating valve 6.
[0018] The outlet of the raw gas cooler 9 is connected to the raw gas methanol water separator 10, and the top outlet of the raw gas methanol water separator 10 is connected to the tail gas washing tower 11 through a pipeline; the top outlet of the raw gas cooler 9 is connected to the tail gas washing tower 11 through a pipeline. The tail gas washing tower 11 is connected to the cold sealing water precooler 12 through a pipeline.
[0019] Example 2
[0020] The device of Example 1 is used to carry out the following process:
[0021] When the device is running, when the conversion gas coming out of the ammonia scrubbing tower 13 passes through the raw gas precooler 2, the raw gas precooler regulating valve 6 and the raw gas cooler regulating valve 8 are used to adjust and control its temperature from 30°C to the raw gas precooler outlet temperature display remote instrument 15 4-8°C. When the raw gas precooler outlet temperature display remote instrument 15 temperature is higher than 8°C, open the raw gas precooler regulating valve 6 to control the flow rate at 36235Nm 3 / h and close the raw gas cooler regulating valve 8 to control the flow rate at 72472Nm 3 / h, when the temperature is lower than 4℃, close the raw gas precooler and adjust the flow rate of valve 6 to 27176Nm 3 / h and open the raw gas cooler regulating valve 8 to control the flow rate at 81531Nm 3 / h, the acidic aqueous solution cooled and separated by the raw gas-water separator 5 is sent to the stripping tower pipeline 3 through the stripping tower valve 4, and then mixed with the methanol after the spray methanol regulating valve 7 from the gas phase outlet of the raw gas-water separator 5 and enters the raw gas methanol-water separator 10.
[0022] First, the directly opened valve is pre-cooled through the cold sealing water precooler 12, and the cold sealing water precooler bypass regulating valve 16 is used to adjust the temperature of the cold sealing water entering the ammonia washing tower to 15-20℃, and then enters the ammonia washing tower 13 for washing and establishing the liquid level of the ammonia washing tower 13. The original temperature of the cold sealing water entering the ammonia washing tower is 35-40℃, and the ammonia in the absorption conversion gas is relatively weak. The ammonia content 17 in the conversion gas is about 5ppm-10ppm. When the cold sealing water precooler 12 is added to reduce the temperature of the cold sealing water entering the ammonia washing tower to 15-20℃, the ammonia 17 content in the conversion gas is detected to be about 2ppm. At the same time, the cumulative ammonia content in the system is reduced from 1200mg / L to 680mg / L, which increases the service life of the methanol in the system.
[0023] After the gas phase temperature of the raw gas water-gas separator 5 is reduced by 4-8°C through the raw gas precooler 2, the saturated water and spray methanol mixture in the ventilation enter the raw gas cooler 9 and condense in the raw gas methanol-water separator 10, and the methanol-water content of 0.15% is reduced to about 0.09%, reducing the amount of spray methanol 7 and the power consumption of the circulating methanol pump; after the amount of saturated water and spray methanol mixture sent to the methanol-water separation tower is reduced, the system's 0.5MPa steam consumption is reduced from 5200kg / h to 4400kg / h, and the system's 1.3MPaz steam is reduced from 3500kg / h to 3000kg / h, which reduces system consumption, energy consumption, and increases economic benefits. At the same time, the tail gas cooling capacity is recovered, and the ammonia content of the conversion gas inlet is reduced from 1200mg / L to 700mg / L in the reflux tank at the top of the distillation tower, reducing the waste of methanol caused by the low-methyl alcohol washing ammonia content and the environmental pressure caused by the increase in the ammonia nitrogen content of the sulfur recovery tail gas.
Claims
1. A device for cooling gasified seal water and precooling conversion gas using low methyl methacrylate cooling capacity, characterized in that: The cold sealing water precooler (12) is connected to the upper part of the ammonia washing tower (13) via a cold sealing water regulating valve (1); the top outlet of the ammonia washing tower (13) is connected to the inlet of the raw gas precooler (2); the outlet of the raw gas precooler (2) is connected to the inlet of the raw gas-water separator (5); and the liquid phase outlet of the raw gas-water separator (5) is connected to the destripping tower pipeline (3) via a destripping tower pipeline valve (4).
2. The device for cooling gasified seal water and precooling conversion gas by using low methyl alcohol cooling capacity according to claim 1 is characterized in that: The gas phase outlet of the raw gas-water separator (5) is connected to the inlet of the raw gas cooler (9), and a methanol spray pipeline (20) is provided on the connected pipeline, and a methanol spray regulating valve (7) is provided on the methanol spray pipeline (20).
3. The device for cooling gasified seal water and precooling conversion gas by using low methyl alcohol cooling capacity according to claim 2, characterized in that: The raw gas cooler (9) is provided with an exhaust gas inlet pipeline (17), a purified gas / liquid nitrogen washed synthesis gas inlet pipeline (18), and a CO2 gas inlet pipeline (19).
4. The device for cooling gasified seal water and precooling converted gas by using low methyl alcohol cooling capacity according to claim 3 is characterized in that: A raw gas cooler regulating valve (8) is provided on the purified gas or cold synthesis gas inlet pipeline (18); the purified gas or cold synthesis gas inlet pipeline (18) is also connected to the shell side inlet of the raw gas water separator (5), and a raw gas precooler regulating valve (6) is provided on the connecting pipeline.
5. The device for cooling gasified seal water and precooling conversion gas by using low methyl alcohol cooling capacity according to claim 4, characterized in that: The outlet of the raw gas cooler (9) is connected to the raw gas methanol water separator (10), and the top outlet of the raw gas methanol water separator (10) is connected to the tail gas washing tower (11) via a pipeline; the top outlet of the raw gas cooler (9) is connected to the tail gas washing tower (11) via a pipeline.
6. The device for cooling gasified seal water and precooling conversion gas by using low methyl alcohol cooling capacity according to claim 5, characterized in that: The tail gas scrubber (11) is connected to the cold sealing water precooler (12) via a pipeline.