CN-122015160-A - System and method for recycling waste heat of tail end conversion gas of conversion process system

CN122015160ACN 122015160 ACN122015160 ACN 122015160ACN-122015160-A

Abstract

The application relates to the technical field of waste heat recovery in coal chemical industry, in particular to a system for recycling waste heat of conversion gas at the tail end of a conversion process system, which comprises a demineralized water heat exchanger, a conversion gas water cooler and a waste heat recovery module arranged between the demineralized water heat exchanger and the conversion gas water cooler. The application uses the heat taken away by the circulating water to preheat the living water and the heating water by adding the waste heat recovery module behind the demineralized water heat exchanger, recycles the waste heat, reduces the consumption of the circulating water, reduces the energy consumption of the subsequent heating to steam/electric heating, simultaneously, can flexibly switch the initial conveying mode according to different seasons and heating peak periods by the intermediate control module, accurately matches the difference of the demands of the living water and the heating water in different periods, dynamically adjusts the conveying flow of the process gas or the input condition of the low-pressure heating steam according to the actual water condition, automatically identifies the heat load change of living areas and factories, and intelligently distributes limited waste heat resources.

Inventors

JIANG CHAOLI
LI WENMING
JI XUHUA

Assignees

国能新疆化工有限公司

Dates

Publication Date: 20260512
Application Date: 20260204

Claims (10)

1. The utility model provides a system of recycle transform process system terminal transform gas waste heat, includes demineralized water heat exchanger and transform gas water cooler, wherein the input of demineralized water heat exchanger communicates with each other with the process gas after multistage separation, transform gas water cooler's input is linked together with the output of demineralized water heat exchanger through the process gas branch pipe, its characterized in that still includes: The waste heat recovery module comprises a domestic water heat exchange module and a heating water heat exchange module, wherein the domestic water heat exchange module and the heating water heat exchange module are arranged between the demineralized water heat exchanger and the conversion gas water cooler in parallel and are used for carrying out secondary recovery on the waste heat of the process gas subjected to heat exchange of the demineralized water heat exchanger; The middle control module is arranged between the demineralized water heat exchanger and the waste heat recovery module and is used for controlling the conveying mode and the conveying flow rate of the process gas conveyed to the domestic water heat exchange module and the heating water heat exchange module.
2. The system for recycling shift gas waste heat from a shift process system of claim 1, wherein said intermediate control module comprises: the first control module is internally provided with three initial conveying modes, and can control the waste heat recovery module to operate in a corresponding initial supply mode according to the actual heating peak period; And the second control module is internally provided with a sub-judging module, and can control the actual conveying conditions of the living water heat exchange module and the heating water heat exchange module according to the actual water use condition of the living area.
3. The system for recycling waste heat of shifted gas at the tail end of a shift process system according to claim 2, wherein the three initial supply modes are respectively a living water priority mode, a heating water priority mode and a normal supply mode, wherein: the domestic water priority mode is that the intermediate control module controls the process gas to be transported and supplied to the domestic water heat exchange module preferentially through the first control module in a non-heating period; The heating water priority mode is that the intermediate control module controls the process gas to be preferentially conveyed and supplied to the heating water heat exchange module through the first control module during a heating peak period; And in the normal supply mode, during a normal heating period, the intermediate control module controls the process gas to carry and supply the domestic water heat exchange module and the heating water heat exchange module at the same conveying flow through the first control module.
4. The system for recycling waste heat of shift gas at tail end of shift process system according to claim 3, wherein one end of said domestic water heat exchanging module and one end of said heating water heat exchanging module are further provided with low pressure heating steam for providing additional heating for the domestic water heat exchanging module and/or the heating water heat exchanging module.
5. The system of claim 4, wherein the sub-determination module is a flow determination sub-module, and the flow determination sub-module determines actual water conditions by determining water flow through the domestic water heat exchange module and the heating water heat exchange module.
6. The system for recycling shift gas waste heat from a shift process system of claim 5, wherein said flow determination submodule comprises: the flow monitor is arranged at the water inlet end or the water outlet end of the domestic water heat exchange module and the heating water heat exchange module and is used for collecting the actual flow of water flowing through the domestic water heat exchange module or the heating water heat exchange module in unit time; And the first judging sub-module is connected with the flow monitor, and is internally provided with a preset judging flow for judging the acquired actual water flow.
7. The system for recycling waste heat of tail end converted gas of a conversion process system according to claim 6, wherein the first judging submodule can judge the actual water flow at the domestic water heat exchange module or the heating water heat exchange module in the current mode through the preset judging flow so as to control the actual conveying flow of process gas at each heat exchange module, wherein the preset judging flow comprises the preset domestic water flow and the preset heating water flow, and the judging process is as follows: If the actual water flow at the domestic water heat exchange module in the current mode is larger than the preset domestic water flow and the actual water flow at the heating water heat exchange module in the current mode is smaller than or equal to the preset heating water flow, the intermediate control module increases the conveying flow of the process gas at the domestic water heat exchange module through the first control module; if the actual water flow at the heating water heat exchange module in the current mode is larger than the preset heating water flow and the actual water flow at the living water heat exchange module is smaller than or equal to the preset living water flow, the intermediate control module increases the conveying flow of the process gas at the heating water heat exchange module through the first control module; If the actual water flow at the domestic water heat exchange module in the current mode is larger than the preset domestic water flow and the actual water flow at the heating water heat exchange module is also larger than the preset heating water flow, the intermediate control module increases the input flow of low-pressure heating steam introduced into the two heat exchange modules through the first control module.
8. The system for recycling waste heat of shift conversion process system according to claim 4, wherein the judging submodule is a temperature difference judging submodule, and the judging submodule can judge actual temperature difference between the domestic water heat exchange module and the heating water heat exchange module in unit time so as to determine actual water condition; the temperature difference judging submodule comprises: The temperature monitor is arranged on the living water heat exchange module and the heating water heat exchange module and is used for collecting the actual temperature difference of the living water heat exchange module or the heating water heat exchange module in unit time; And the second judging sub-module is connected with the temperature monitor, and is internally provided with a preset judging temperature difference for judging the acquired actual temperature difference.
9. The system for recycling waste heat of a shift process system according to claim 8, wherein the second determining submodule can determine an actual temperature difference at the domestic water heat exchange module or the heating water heat exchange module according to the preset determination temperature difference to control an actual flow rate of the process gas at each heat exchange module, wherein the preset determination temperature difference includes a preset living water temperature difference and a preset heating water temperature difference, and the determining process is as follows: If the actual temperature difference at the domestic water heat exchange module in the current mode is larger than the preset domestic water temperature difference and the actual temperature difference of the heating water heat exchange module is smaller than or equal to the preset heating water temperature difference, the intermediate control module increases the conveying flow of the process gas at the domestic water heat exchange module through the first control module; If the actual temperature difference at the heating water heat exchange module in the current mode is larger than the preset heating water temperature difference and the actual temperature difference at the living water heat exchange module is smaller than or equal to the preset living water fixed temperature difference, the intermediate control module increases the conveying flow of the process gas at the heating water heat exchange module through the first control module; If the actual temperature difference at the domestic water heat exchange module in the current mode is larger than the preset domestic water temperature difference and the actual temperature difference at the heating water heat exchange module is also larger than the preset heating water temperature difference, the intermediate control module increases the input flow of low-pressure heating steam flowing into the two heat exchange modules through the first control module.
10. The recycling method of a system for recycling waste heat of shift gas at an end of a shift process system according to any one of claims 1 to 9, comprising: step S1, introducing the process gas subjected to multistage separation into a desalted water heat exchanger for preliminary heat exchange and cooling; step S2, selecting an operation mode through an intermediate control module according to the current season and heating requirements, wherein the operation mode comprises a living water priority mode, a heating water priority mode or a normal supply mode; step S3, conveying the process gas subjected to heat exchange by the desalted water heat exchanger to a domestic water heat exchange module and a heating water heat exchange module respectively through an intermediate control module according to the initial distribution proportion of the selected operation mode; S4, acquiring the actual water flow or the actual temperature difference flowing through the domestic water heat exchange module and the heating water heat exchange module in real time through a flow judgment sub-module and/or a temperature difference judgment sub-module; s5, comparing the acquired actual value with a preset judging flow or a preset judging temperature difference in a corresponding mode, and dynamically adjusting the process air flow delivered to each heat exchange module according to a comparison result; And S6, merging the process gas subjected to heat exchange and temperature reduction by the waste heat recovery module, conveying the process gas to a conversion gas water cooler for final cooling, and then conveying the process gas to an ammonia washing tower for subsequent treatment.

Description

System and method for recycling waste heat of tail end conversion gas of conversion process system Technical Field The application relates to the technical field of waste heat recovery in coal chemical industry, in particular to a system and a method for recycling waste heat of tail end conversion gas of a conversion process system. Background In the shift unit of the coal chemical industry purification apparatus, a partial shift process is generally adopted. Cooling the crude water gas by a waste heat boiler, separating condensate, and then, partially entering a shift converter for shift reaction, the other part is used as gas distribution and is not transformed, the two are combined to regulate the hydrogen-carbon ratio. The converged process gas is subjected to multistage separation and heat exchange, sequentially enters a desalted water heat exchanger and a converted gas water cooler, is finally cooled to about 40 ℃, enters an ammonia washing tower for washing, and is then sent to an acid gas removal unit. In the prior art, the utilization of the waste heat at the high and medium temperatures higher than 150 ℃ is wide in all production fields, the waste heat is mainly used for steam generation and power generation, and the low-grade waste heat lower than 150 ℃ is mainly cooled by consuming a large amount of circulating water, as in the process, after the converted gas is subjected to heat exchange to about 60 ℃ through a desalted water heat exchanger, more waste heat still exists, but the converted gas directly enters a water cooler in the prior art and is taken away by the circulating water cooling. This not only causes waste of low-grade heat energy, but also increases the load (water consumption, wind energy consumption) of the circulating water system. While domestic water and heating water in factories and living areas are required to consume a large amount of steam or electric power for heating, along with the improvement of the requirements of green low carbon, energy conservation and consumption reduction in recent years, the waste heat of the conversion gas can be fully recycled, so that an energy-saving transformation upgrading measure is provided, and the waste heat recovery of the conversion gas at the tail end of the conversion system is optimized and transformed. Disclosure of Invention The application provides a system and a method for recycling waste heat of conversion gas at the tail end of a conversion process system, which are used for solving the problems that the prior art lacks recycling of low-grade conversion gas waste heat, so that a large amount of available heat energy is wasted and the waste heat recycling rate is lower. The application provides a system for recycling waste heat of conversion gas at the tail end of a conversion process system, which comprises: The system comprises a demineralized water heat exchanger and a conversion gas water cooler, wherein the input end of the demineralized water heat exchanger is communicated with the process gas after multistage separation, and the input end of the conversion gas water cooler is communicated with the output end of the demineralized water heat exchanger through a process gas branch pipe; Further comprises: The waste heat recovery module comprises a domestic water heat exchange module and a heating water heat exchange module, wherein the domestic water heat exchange module and the heating water heat exchange module are arranged between the demineralized water heat exchanger and the conversion gas water cooler in parallel and are used for carrying out secondary recovery on the waste heat of the process gas subjected to heat exchange of the demineralized water heat exchanger; The middle control module is arranged between the demineralized water heat exchanger and the waste heat recovery module and is used for controlling the conveying mode and the conveying flow rate of the process gas conveyed to the domestic water heat exchange module and the heating water heat exchange module. Preferably, the intermediate control module includes: the first control module is internally provided with three initial conveying modes, and can control the waste heat recovery module to operate in a corresponding initial supply mode according to the actual heating peak period; And the second control module is internally provided with a sub-judging module, and can control the actual conveying conditions of the living water heat exchange module and the heating water heat exchange module according to the actual water use condition of the living area. Preferably, the three initial supply modes are respectively a living water priority mode, a heating water priority mode and a normal supply mode, wherein: the domestic water priority mode is that the intermediate control module controls the process gas to be transported and supplied to the domestic water heat exchange module preferentially through the first control module in a non-heating period; The hea