Carbon monoxide conversion system and method for device for preparing methanol by gasifying coal water slurry
阅读说明：本技术 一种水煤浆气化制甲醇装置一氧化碳变换系统及方法 (Carbon monoxide conversion system and method for device for preparing methanol by gasifying coal water slurry ) 是由 兰荣亮 谢东升 马炯 汪根宝 王靓 于 2020-05-20 设计创作，主要内容包括：本发明属于煤化工装置工艺设计优化和余热回收利用技术领域,本发明提供一种水煤浆气化制甲醇装置一氧化碳变换系统及方法,结合煤制甲醇装置一氧化碳部分变换和能量利用的特点,优化和搭建工艺流程,提出将来自上游气化装置的粗合成气分为两股,其中一股经过粗煤气预热器升温后经过脱毒槽进入变换炉进行化学反应；另外一股不参与反应的未变换气,作为配气与反应后的变换气混合。在满足工艺生产要求的同时获得良好能量利用效果,并节省了投资成本。(The invention belongs to the technical field of optimization of process design and waste heat recovery of coal chemical industry devices, and provides a carbon monoxide conversion system and a carbon monoxide conversion method of a device for preparing methanol by gasifying coal water slurry, wherein the carbon monoxide conversion system and the carbon monoxide conversion method are characterized by combining partial conversion and energy utilization of the device for preparing methanol by coal, the process flow is optimized and set up, and the crude synthesis gas from an upstream gasification device is divided into two streams, wherein one stream enters a conversion furnace for chemical reaction through a detoxication groove after being heated by a crude gas preheater; the other unchanged gas without participating in the reaction is used as the gas to be mixed with the converted gas after the reaction. The process production requirement is met, the good energy utilization effect is obtained, and the investment cost is saved.)
1. The utility model provides a coal slurry gasification system methyl alcohol device carbon monoxide shift system which characterized in that: the system comprises a first gas-liquid separator (1), a second gas-liquid separator (8), a third gas-liquid separator (10) and a fourth gas-liquid separator (13); the output pipeline of the crude synthesis gas is connected with a first gas-liquid separator (1), and the output end at the top of the first gas-liquid separator (1) is divided into two paths: one path is connected with the input end of the detoxification groove (3) through a crude gas preheater (2);
the output end at the bottom of the detoxification tank (3) is connected with the input end at the top of the shift converter (4), the output end of the bottom of the shift converter (4) is connected with a medium-pressure steam superheater (5) through a raw gas preheater (2), the output end of the medium-pressure steam superheater (5) is connected with a medium-pressure steam generator (6), the other path is connected with the outlet end of the medium-pressure steam generator (6) and then enters a second gas-liquid separator (8) through the medium-pressure steam generator (7), the output end of the top of the second gas-liquid separator (8) is connected with a third gas-liquid separator (10) through a low-pressure steam generator (9), and the third gas-liquid separator (10) enters a fourth gas-liquid separator (13) through a desalted water preheater (11) and a water cooler (12), and the output end of the top of the fourth gas-liquid separator (13) is communicated with the outside.
2. The carbon monoxide shift system of the coal water slurry gasification methanol preparation device according to claim 1, characterized in that: the detoxification tank (3) and the shift converter (4) are heat-insulating fixed bed reactors.
3. A method for realizing carbon monoxide shift of a device for preparing methanol by gasifying coal water slurry by using the system of claim 1, which is characterized by comprising the following steps: the method comprises the following steps:
1) after crude synthesis gas from an upstream coal water slurry gasification unit enters a first gas-liquid separator, dividing a top gas phase into two gas streams, heating one process gas stream to 260-300 ℃ by a crude gas preheater, entering a detoxification tank to remove impurities, and entering a shift converter to perform carbon monoxide shift reaction;
2) the temperature of the shift converter outlet is 390-430 ℃, the temperature of the shift converter outlet is reduced to 350-370 ℃ through a crude gas preheater, the shift converter outlet enters a medium-pressure steam superheater, saturated steam is superheated and then sent to an out-of-range steam pipe network, and the shift converter outlet enters a medium-pressure steam generator to produce a byproduct saturated steam;
3) the converted gas is further cooled to 220-240 ℃, then is mixed with another unconverted gas and enters a medium-low pressure steam generator to produce medium-low pressure saturated steam as a byproduct, the converted gas is cooled to 200-220 ℃, then enters a second gas-liquid separator, and after a liquid phase is separated at the bottom, a top gas phase enters the low pressure steam generator to produce the low-pressure saturated steam as a byproduct;
4) the converted gas is further cooled to 165-175 ℃, then enters a third gas-liquid separator, the top gas phase is cooled through a desalted water preheater and a water cooler, then enters a fourth gas-liquid separator, and the gas discharged from the fourth gas-liquid separator is sent out;
5) and bottom condensate of the second gas-liquid separator and the third gas-liquid separator is merged and then sent to a gasification unit, and bottom condensate of the fourth gas-liquid separator is sent to the outside for further treatment.
4. The carbon monoxide shift method for the device for preparing methanol by gasifying coal water slurry according to claim 4, which is characterized in that: the flow rate of the crude synthesis gas at the top outlet of the first gas-liquid separator (1) as the unchanged gas is 0.4-0.6.
5. The carbon monoxide shift method for the device for preparing methanol by gasifying coal water slurry according to claim 1, which is characterized in that: the inlet temperature of the detoxification tank (3) and the inlet temperature of the shift converter (4) are controlled to be 260-300 ℃.
6. The carbon monoxide shift method for the device for preparing methanol by gasifying coal water slurry according to claim 1, which is characterized in that: the heat generated in the shift reaction process is used for generating steam as a byproduct, and the steam pressure grade is 0.4 Mpag-4.0 MPag.
7. The carbon monoxide shift method for the device for preparing methanol by gasifying coal water slurry according to claim 1, which is characterized in that: the operation temperature of the first gas-liquid separator (1) is controlled to be 240-250 ℃, the operation temperature of the second gas-liquid separator (8) is controlled to be 200-220 ℃, the operation temperature of the third gas-liquid separator (10) is controlled to be 165-180 ℃, and the operation temperature of the fourth gas-liquid separator (13) is controlled to be 35-40 ℃.
Technical Field
The invention belongs to the technical field of process design optimization and waste heat recovery of coal chemical engineering devices, and relates to a carbon monoxide shift system and a carbon monoxide shift method of a device for preparing methanol by gasifying coal water slurry, in particular to industrial application of a shift technology to a methanol production device.
Background
The content of CO in the raw synthesis gas from an upstream coal water slurry gasification device is high, the dry basis content is about 40-47%, and the water-gas ratio is high, generally between 1.3-1.5, and sometimes as high as about 1.7. In the conversion device technology matched with the coal water slurry gasification for preparing the methanol, CO and water are required to react and convert into CO through the carbon monoxide conversion catalytic reaction2And H2The composition of the process gas is adjusted so that it satisfies f ═ H2-CO2)/(CO+CO2) 2.0-2.15, and then entering a methanol synthesis device.
In the existing coal-to-methanol carbon monoxide conversion process, a non-converted gas bypass pipeline is arranged at an inlet and an outlet of a conversion furnace, and the following problems mainly exist: (1) the heat utilization is unreasonable, the unchanged gas is heated by the crude gas preheater and then enters a subsequent cooling system through a shift converter bypass, and the bypass pipeline is unreasonable in arrangement, so that energy waste is caused; (2) the gas load of the pipeline and the equipment from the pipeline of the coarse synthesizer to the inlet of the shift converter is large, and the equipment investment is high; (3) the catalyst airspeed of the detoxification tank is large, and the service life is short.
Therefore, the carbon monoxide conversion technology matched with reasonable selection and optimized design is particularly important by combining the component characteristics of the coal water slurry gasification crude synthesis gas, and is widely concerned by researchers and designers in the industry in recent years.
Disclosure of Invention
The invention aims to provide a carbon monoxide conversion system and a carbon monoxide conversion process for a device for preparing methanol by gasifying coal water slurry, aiming at the defects in the prior art. Combining the characteristics of partial conversion and energy utilization of the coal-to-methanol, optimizing and building a process flow, and providing that the crude synthesis gas from an upstream gasification device is divided into two streams, wherein one stream enters a conversion furnace for reaction through a detoxication groove after being heated by a crude gas preheater; the other unchanged gas without participating in the reaction is used as the gas to be mixed with the converted gas after the reaction. The process production requirement is met, the good energy utilization effect is obtained, and the investment cost is saved.
The purpose of the invention can be realized by the following technical scheme:
the utility model provides a coal slurry gasification system methyl alcohol device carbon monoxide transform system, this system includes first vapour and liquid separator, second vapour and liquid separator, third vapour and liquid separator and fourth vapour and liquid separator, and the output pipeline of crude synthetic gas links to each other with first vapour and liquid separator, the output at first vapour and liquid separator top is divided into two the tunnel: one path is connected with the input end of the detoxification groove through a crude gas preheater;
the output of detoxication tank bottom links to each other with the input at shift converter top, the output of shift converter bottom passes through the coarse coal gas preheater and links to each other with medium pressure steam superheater, medium pressure steam superheater's output links to each other with medium pressure steam generator, and in addition link to each other all the way and medium pressure steam generator exit end back and get into second vapour and liquid separator through medium and low pressure steam generator, the output at second vapour and liquid separator top links to each other with third vapour and liquid separator through low pressure steam generator, third vapour and liquid separator gets into fourth vapour and liquid separator through demineralized water preheater and water cooler, the output at fourth vapour and liquid separator top with send to go out.
In the above system: the detoxification tank and the shift converter are heat-insulating fixed bed reactors.
A carbon monoxide conversion method of a device for preparing methanol by gasifying coal water slurry by using the system comprises the following steps:
1) after crude synthesis gas from an upstream coal water slurry gasification unit enters a first gas-liquid separator, dividing a top gas phase into two gas streams, heating one process gas stream to 260-300 ℃ by a crude gas preheater, entering a detoxification tank to remove impurities, and entering a shift converter to perform carbon monoxide shift reaction;
2) the temperature of the shift gas at the outlet of the shift converter is 390-430 ℃, the shift gas is cooled to 350-370 ℃ through a crude gas preheater, the shift gas enters a medium-pressure steam superheater, saturated steam is superheated and then sent to an out-of-range steam pipe network, and the shift gas enters a medium-pressure steam generator to produce a byproduct saturated steam;
3) the converted gas is further cooled to 220-240 ℃, then is mixed with another unconverted gas and enters a medium-low pressure steam generator to produce medium-low pressure saturated steam as a byproduct, the converted gas is cooled to 200-220 ℃, then enters a second gas-liquid separator, and after a liquid phase is separated at the bottom, a top gas phase enters the low pressure steam generator to produce the low-pressure saturated steam as a byproduct;
4) the converted gas is further cooled to 165-175 ℃, then enters a third gas-liquid separator, the top gas phase is cooled through a desalted water preheater and a water cooler, then enters a fourth gas-liquid separator, and the gas discharged from the fourth gas-liquid separator is sent out;
5) the bottom condensate of the second gas-liquid separator and the bottom condensate of the third gas-liquid separator are merged and then sent to a gasification unit, and the bottom condensate of the fourth gas-liquid separator is sent to the outside for further treatment
The method comprises the following steps: the flow rate of the crude synthesis gas at the top outlet of the first gas-liquid separator as the unchanged gas is 0.4-0.6.
The method comprises the following steps: and the inlet temperatures of the detoxification tank and the shift converter are controlled to be 260-300 ℃.
The method comprises the following steps: the heat generated in the shift reaction process is used for generating steam as a byproduct, and the steam pressure grade is 0.4 Mpag-4.0 MPag.
The method comprises the following steps: the operation temperature of the first gas-liquid separator (1) is controlled to be 240-250 ℃, the operation temperature of the second gas-liquid separator (8) is controlled to be 200-220 ℃, the operation temperature of the third gas-liquid separator (10) is controlled to be 165-180 ℃, and the operation temperature of the fourth gas-liquid separator (13) is controlled to be 35-40 ℃.
The invention has the beneficial effects that:
compared with the prior art, the method divides the crude synthesis gas from the upstream coal gasification unit into two streams, wherein one stream enters the shift converter for reaction through the detoxification groove after being heated by the crude gas preheater; and the other strand is used for mixing the unchanged gas and the transformed process gas, the gas flow accounts for about 40-60%, the gas load entering the detoxification tank and the transformation furnace is greatly reduced on the premise of meeting the process production requirements, and the method has the characteristics of good energy integration effect, reasonable waste heat utilization, low construction investment and the like.
Drawings
FIG. 1 is a schematic process flow diagram of the present invention.
In the figure: 1-a first gas-liquid separator, 2-a crude gas preheater, 3-a detoxification tank, 4-a shift converter, 5-a medium-pressure steam superheater, 6-a medium-pressure steam generator, 7-a medium-low pressure steam generator, 8-a second gas-liquid separator, 9-a low-pressure steam generator, 10-a third gas-liquid separator, 11-a desalted water preheater, 12-a water cooler and 13-a fourth gas-liquid separator.
Detailed Description
The invention is further illustrated by the following examples, without limiting the scope of the invention:
a carbon monoxide conversion system and a process of a device for preparing methanol by gasifying coal water slurry are characterized in that: the system comprises a first gas-liquid separator (1), a second gas-liquid separator (8), a third gas-liquid separator (10) and a fourth gas-liquid separator (13); the output pipeline of the crude synthesis gas is connected with a first gas-liquid separator (1), and the output end at the top of the first gas-liquid separator (1) is divided into two parts: one of the two branches is connected with the input end of the detoxification groove (3) through a crude gas preheater (2); the output of detoxification groove (3) bottom links to each other with the input at shift converter (4) top, the output of shift converter (4) bottom passes through crude gas preheater (2) and links to each other with middling pressure steam superheater (5), the output of middling pressure steam superheater (5) links to each other with middling pressure steam generator (5), and another strand links to each other with middling pressure steam generator (5) exit end back and gets into second vapour and liquid separator (8) through middling pressure steam generator (7), the output at second vapour and liquid separator (8) top passes through low pressure steam generator (9) and links to each other with third vapour and liquid separator (10), third vapour and liquid separator (10) get into fourth vapour and liquid separator (13) through demineralized water preheater (11) and water cooler (12). And the output end of the top of the fourth gas-liquid separator (13) is communicated with the outside.