Coal water slurry gasification method and device

Abstract

The invention discloses a coal water slurry gasification method and device, and relates to the technical field of coal chemical industry. The method comprises the following steps: in the first start-up process of coal water slurry gasification, introducing cooled shift gas as quench gas into at least one of a detoxification tank, a first shift converter and a second shift converter so as to control the temperature of a catalyst bed, and stopping introducing the cooled shift gas after the temperature of the bed is stable. In the first start-up process of coal water slurry gasification, cooled shift gas from a shift gas ammonia washing tower is sequentially introduced into a detoxification tank, a first shift converter and a second shift converter, bed reaction heat is directly absorbed by utilizing the low-temperature characteristic of the cooled shift gas, and meanwhile, the concentration of reaction components in crude synthesis gas is diluted; therefore, the temperature rise speed is effectively inhibited in the initial adsorption and reaction heat release stages of the catalyst; the temperature of a plurality of reactor beds can be accurately controlled, catalyst sintering inactivation and equipment damage caused by heat accumulation in a traditional mode are avoided, and the safety and operation stability in the start-up process are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal chemical industry, and in particular to a coal water slurry gasification method and device. BACKGROUND

[0002] In the field of coal chemical industry, coal is converted into syngas, which is then used to produce chemicals such as methanol and ethylene glycol. This process begins with coal water slurry gasification: coal powder is mixed with water into a slurry, which is fed into a high-pressure reactor to react under high temperature and pressure to produce raw syngas. The main components of raw syngas include water vapor, carbon monoxide, hydrogen, carbon dioxide, hydrogen sulfide, and methane, etc. Since the proportion of carbon monoxide and hydrogen in raw syngas is usually not suitable for direct use in downstream production, it needs to be adjusted through a shift reaction.

[0003] During the start-up phase after the first loading of shift catalyst in the coal water slurry gasification, the existing technology faces a serious problem of over-temperature. When the catalyst is used for the first time, the entry of raw syngas into the furnace will trigger two heat effects: one is the adsorption heat generated by the adsorption of gas components on the surface of the catalyst, and the other is that the shift reaction itself is an exothermic reaction. The superposition of the two causes the temperature of the catalyst bed to rise rapidly, which may permanently damage the activity of the catalyst, shorten the service life of the equipment, and even cause safety accidents such as leakage. Existing solutions include the introduction of inert gas, the addition of water vapor, or the adjustment of start-up load, but these methods all have significant defects. The effect of inert gas introduction is limited and cannot effectively suppress the temperature jump; water vapor can lower the temperature, but excessive water vapor will condense into liquid water, corrode the catalyst and reduce its service life; the adjustment of start-up load is difficult to control accurately, and the heat accumulates faster at low load, while the reaction intensifies the temperature rise at high load. These problems are particularly prominent in high-pressure coal water slurry gasification processes, because the pressure conditions exacerbate heat accumulation, and the adiabatic design of the shift furnace lacks an active cooling mechanism. Therefore, there is an urgent need to develop a reliable method to prevent over-temperature during the first start-up and ensure process safety and efficiency. SUMMARY

[0004] Therefore, the present application provides a coal water slurry gasification method and device, which mainly aims to solve the technical problem that the temperature of the catalyst bed rises rapidly when the catalyst is used for the first time in the traditional coal water slurry gasification process, which may permanently damage the activity of the catalyst, shorten the service life of the equipment, and even cause safety accidents such as leakage.

[0005] In one aspect, the present application provides a coal water slurry gasification method, comprising: During the first start-up process of coal water slurry gasification, cooling the shift gas to obtain cooled shift gas, and introducing the cooled shift gas into at least one of the detoxification tank, the first shift furnace and the second shift furnace as cold shock gas to control the temperature of the catalyst bed, and stopping the introduction of the cooled shift gas after the temperature of the catalyst bed stabilizes.

[0006] In one possible implementation, the method further comprises: The detoxification tank, the first shift converter and the second shift converter are heated to 220-300℃ by nitrogen, and after the heating is completed, the nitrogen is cut off and the detoxification tank, the first shift converter and the second shift converter are isolated.

[0007] In a feasible embodiment, the method further comprises: The crude synthesis gas is introduced into the detoxification tank, the start-up bypass of the detoxification tank is gradually closed, the front and rear hand valves of the detoxification tank are opened, the cooled shift gas in the shift gas ammonia washing tower is introduced as cold blast gas, the bed temperature is prevented from rising too fast by adjusting the flow, and after the temperature is stabilized, the first shift converter is entered.

[0008] In a feasible embodiment, the method further comprises: The crude synthesis gas is introduced into the detoxification tank, the start-up bypass of the detoxification tank is gradually closed, the front and rear hand valves of the detoxification tank are opened, the cooled shift gas in the shift gas ammonia washing tower is introduced as cold blast gas, the bed temperature is prevented from rising too fast by adjusting the flow, and after the temperature is stabilized, the first shift converter is entered.

[0009] In a feasible embodiment, the method further comprises: The crude synthesis gas is introduced into the detoxification tank, the start-up bypass of the detoxification tank is gradually closed, the front and rear hand valves of the detoxification tank are opened, the cooled shift gas in the shift gas ammonia washing tower is introduced as cold blast gas, the bed temperature is prevented from rising too fast by adjusting the flow, and after the temperature is stabilized, the first shift converter is entered.

[0010] In a feasible embodiment, the method further comprises: The crude synthesis gas is introduced into the detoxification tank, the start-up bypass of the detoxification tank is gradually closed, the front and rear hand valves of the detoxification tank are opened, the cooled shift gas in the shift gas ammonia washing tower is introduced as cold blast gas, the bed temperature is prevented from rising too fast by adjusting the flow, and after the temperature is stabilized, the first shift converter is entered.

[0011] In a feasible embodiment, the method further comprises: The final obtained shift gas and unshifted gas are pressurized to 5.0-6.5 MPa(G), the hydrogen-carbon ratio is adjusted, and after being qualified, they are sent to the downstream device.

[0012] In another aspect, the present application provides a coal water slurry gasification device, comprising: A crude synthesis gas inlet; A shift pipeline connected with the crude synthesis gas inlet; An unshifted pipeline connected with the crude synthesis gas inlet; A shift gas downstream device connected with the shift pipeline; unconverted gas downstream unit connected to the unconverted gas line.

[0013] In one possible embodiment, the shift line and the unconverted gas line comprise: a first gas-liquid separator connected to the raw syngas inlet; a detoxification tank connected to the first gas-liquid separator; a first shift converter connected to the detoxification tank; a feed gas heat exchanger connected to the first shift converter; a medium pressure steam superheater connected to the first shift converter; a low pressure steam superheater connected to the medium pressure steam superheater; a medium pressure steam waste heat boiler connected to the low pressure steam superheater; a second shift converter connected to the medium pressure steam waste heat boiler; a low pressure steam waste heat boiler connected to the second shift converter; a second gas-liquid separator connected to the low pressure steam waste heat boiler; a low-low pressure steam waste heat boiler connected to the second gas-liquid separator; a third gas-liquid separator connected to the low-low pressure steam waste heat boiler; a desalted water heat exchanger connected to the third gas-liquid separator; a circulating water cooler connected to the desalted water preheater; a shift gas ammonia wash column connected to the circulating water cooler; a shift gas high pressure hydrogen rich flare connected to the shift gas ammonia wash column; an unconverted gas ammonia wash column connected to the raw syngas inlet; an unconverted gas high pressure hydrogen rich flare connected to the unconverted gas ammonia wash column.

[0014] In one possible embodiment, the unit further comprises: injection points comprising a first injection point disposed at the detoxification tank inlet, a second injection point disposed at the first shift converter inlet, and a third injection point disposed at the second shift converter inlet; A booster is connected with the shift gas ammonia washing tower, for boosting the shift gas and delivering to the first injection point, the second injection point and the third injection point.

[0015] The application provides a coal water slurry gasification method and device, and the method comprises the following steps: during the first start-up process of the coal water slurry gasification, cooling shift gas from a shift gas ammonia washing tower is introduced into at least one of a detoxification tank, a first shift converter and a second shift converter as cooling gas to control the temperature of the catalyst bed, and the cooling shift gas is stopped after the temperature of the catalyst bed is stabilized. In the application, the cooling shift gas from the shift gas ammonia washing tower is introduced into the detoxification tank, the first shift converter and the second shift converter in sequence as cooling gas during the first start-up process of the coal water slurry gasification, the low-temperature characteristics of the cooling shift gas are used to directly absorb the heat of the bed reaction, and the concentration of the reaction components in the crude synthesis gas is diluted, so that the temperature rising speed is effectively inhibited in the initial adsorption and reaction heat release stage of the catalyst. The application realizes the precise control of the bed temperature of multiple reactors by gradually switching the main and auxiliary lines and adjusting the cooling gas flow, avoids the catalyst sintering deactivation and equipment damage caused by heat accumulation in the traditional way, and significantly improves the safety and operation stability of the start-up process.

[0016] Other features and advantages of the application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the application. The purposes and other advantages of the application can be realized and attained by the structure particularly pointed out in the written description, the claims, and the appended drawings.

[0017] The technical solutions of the application will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings, which are included to provide a further understanding of the application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings: Figure 1 A flowchart of a coal water slurry gasification method provided by an embodiment of the application is shown; Figure 2 A structural diagram of a coal water slurry gasification device provided by an embodiment of the application is shown.

[0019] In the drawings: 10, raw synthesis gas; 20, first gas-liquid separator; 21, high-temperature condensate; 30, detoxification tank; 31, raw gas heat exchanger; 32, first injection point; 40, first shift converter; 41, second injection point; 50, second shift converter; 51, medium-pressure steam superheater; 52, low-pressure steam superheater; 53, medium-pressure steam waste heat boiler; 54, third injection point; 60, second gas-liquid separator; 61, low-pressure steam waste heat boiler; 62, high-temperature condensate; 70, third gas-liquid separator; 71, low-low-pressure steam waste heat boiler; 72, high-temperature condensate; 80, shift gas ammonia wash tower; 81, desalted water heat exchanger; 82, circulating water cooler; 83, shift gas downstream device; 84, low-temperature condensate; 85, shift gas high-pressure hydrogen-rich flare; 90, unshifted gas process; 100, unshifted gas ammonia wash tower; 101, unshifted gas downstream device; 102, low-temperature condensate; 103, unshifted gas high-pressure hydrogen-rich flare; 110, booster. DETAILED DESCRIPTION

[0020] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0021] In addition, the terms "first", "second", "third", etc. are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features referred to. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0022] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing", and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] The water coal slurry gasification pressure is generally 6.5 MPa (G), and the main components of the generated crude synthesis gas are H2O, CO, H2, CO2, H2S, CH4, etc. Generally, the hydrogen carbon ratio needs to be adjusted through a shift reaction, and sent to the downstream device to produce different chemicals, such as methanol, ethylene glycol, acetic acid, oil, etc. In the shift process, the first shift converter generally uses an axial-radial adiabatic shift converter, and less uses an isothermal shift converter, and the second shift converter generally uses a radial adiabatic shift converter. Some processes set a detoxification tank at the inlet of the first shift converter to remove impurities and poisons in the crude synthesis gas. Although the isothermal shift converter uses water to remove reaction heat in time, the catalyst bed temperature is maintained within a reasonable range, and the shift rate is higher, but the structure of the shift converter is complex, and after the heat exchange pipe leaks, the synthesis gas will enter the steam, which has a certain safety risk. In order to reduce the influence of synthesis gas components on the corrosion and stress of the shift converter, the structure of the shift converter is often designed to be simpler, and even the unloading port at the lower part of the bed is cancelled, so as to increase the operation time of the equipment and reduce the safety risk.

[0024] The shift converter catalyst is crucial to the shift reaction. The shift catalyst is generally a wide-temperature sulfur-tolerant cobalt-molybdenum catalyst with magnesium-aluminum spinel as the carrier, and the active component is sulfided cobalt and molybdenum. Most processes use pre-sulfided catalyst when loading the catalyst, which only needs to be heated to the required temperature to remove the adsorbed water in the catalyst, so that the shift reaction can be carried out, avoiding the need for sulfurization before starting to have the best shift activity, thereby saving the start-up time. After the catalyst is loaded for the first time, when the crude synthesis gas enters the catalyst bed, the activity of the sulfided cobalt-molybdenum catalyst is high, and the catalyst rapidly heats up in a short time, exceeding the normal operating temperature, and even reaching 500°C in the adiabatic shift converter, which may affect the catalyst activity and shorten the service life of the equipment, and even cause equipment damage and leakage problems.

[0025] The rapid rise of the shift cobalt-molybdenum catalyst bed temperature has two main processes: first, the components H2O, CO, H2, CO2, etc. in the crude synthesis gas are adsorbed on the catalyst, and the adsorption process will produce adsorption heat, which will preliminarily heat up the catalyst bed temperature; second, the shift reaction CO + H2O = H2 + CO2 is an exothermic reaction, which will generate 41.4 kJ / mol of heat during the reaction process, further exacerbating the rapid rise of the catalyst bed temperature, thereby rapidly rising the catalyst bed temperature.

[0026] How to avoid the adiabatic fixed bed shift catalyst first loading after starting not over temperature, become the problem to be solved. The shift catalyst is generally filled with nitrogen to heat the catalyst, generally heated to 220-300℃, then the crude synthesis gas is introduced for reaction, generally control over temperature method has the introduction of inert gas, the introduction of water vapor and adjustment of starting load, the introduction of inert gas is generally nitrogen, can not better solve the problem of catalyst over temperature. After the introduction of water vapor, it will participate in the shift reaction, so that the shift rate rises, more heat will be generated, after the introduction of too much water vapor, although the bed temperature will be reduced, there is a risk that the steam condensation will affect the service life of the catalyst. The starting load adjustment becomes a way, when the load is low, the heat generated by the bed temperature cannot be taken away with the gas flow in time, the temperature rises rapidly, the load needs to be increased to take away more heat; when the load is high, more heat will be generated, which will make the bed temperature rise rapidly and rise to a higher point in advance.

[0027] According to the generation process of the heat of the shift reaction, the application provides a method for avoiding over temperature during the first start of the catalyst after the filling of the adiabatic shift reactor of the coal water slurry gasification.

[0028] Referring to Figure 1 , a flowchart of a coal water slurry gasification method provided by the application is provided, which comprises: In the first start of the coal water slurry gasification, cooling after the shift gas is introduced into at least one of the detoxification tank, the first shift reactor and the second shift reactor as a cooling gas to control the bed temperature of the catalyst, and the cooling gas is stopped after the bed temperature is stable.

[0029] In the above embodiment, the specific method comprises introducing the cooling gas into one or more units of the detoxification tank, the first shift reactor and the second shift reactor during the initial feeding stage of the system. By adjusting the flow of the cooling gas, the heat generated by the catalyst bed during the reaction can be effectively absorbed, so that the bed temperature is maintained in a suitable range. After observing that the bed temperature tends to be stable and the reaction state is stable, the cooling gas can be gradually reduced and finally stopped.

[0030] The application can significantly reduce the risk of catalyst over temperature and even affect the sintering of the catalyst due to the violent reaction in the initial stage, which is beneficial to maintain the reaction activity and service life of the catalyst. At the same time, by introducing an external gas source for temperature regulation, the operation flexibility and controllability of the starting stage are improved, which lays a good foundation for subsequent stable operation.

[0031] Further, the method further comprises: The detoxification tank, the first shift reactor and the second shift reactor are heated to 220-300℃ by nitrogen, and the nitrogen is cut off and the detoxification tank, the first shift reactor and the second shift reactor are isolated after the heating is completed.

[0032] In the above embodiment, further comprising preheating the detoxification tank, the first shift converter and the second shift converter with nitrogen before the process gas is introduced. By controlling the flow rate and temperature of the nitrogen, the reaction units are gradually raised to the required operating temperature range. After the temperature rising process is completed, the nitrogen supply is cut off in time, and each device is isolated to prepare for the subsequent introduction of the raw synthesis gas.

[0033] The present application can avoid the condensation of components in the process gas under low temperature conditions or the adverse reaction with the catalyst, while reducing the thermal stress of the equipment. Using inert gas as the temperature rising medium significantly improves the safety of the start-up process.

[0034] Further, the method further comprises: Introducing the raw synthesis gas through the start-up bypass line of the detoxification tank, the first shift converter and the second shift converter to warm up the shift pipeline and the unshifted pipeline to 150-220°C, and the shift gas is sent to the high-pressure hydrogen-rich flare through the shift gas ammonia washing tower, and the unshifted gas is sent to the high-pressure hydrogen-rich flare through the unshifted gas ammonia washing tower.

[0035] In the above embodiment, further comprising introducing the raw synthesis gas through the start-up bypass line of each reaction unit to preheat the pipeline. By controlling the gas flow rate and flow rate, the pipeline equipment in the main process and unshifted gas flow path is gradually raised to the target preheating temperature. During this period, the shift gas and the unshifted gas are respectively sent to the corresponding ammonia washing tower for treatment, and then sent to the high-pressure hydrogen-rich flare system.

[0036] The present application can avoid the stress deformation or damage of the equipment caused by the sudden contact of the low-temperature pipeline with the high-temperature process gas, while effectively removing the impurities in the system.

[0037] Further, the method further comprises: Introducing the raw synthesis gas into the detoxification tank, gradually closing the start-up bypass line of the detoxification tank, opening the front and rear manual valves of the detoxification tank, introducing the cooled shift gas in the shift gas ammonia washing tower as cold gas, and adjusting the flow rate to prevent the bed temperature from rising too fast. After the temperature stabilizes, the gas is sent to the first shift converter.

[0038] In the above embodiment, further comprising introducing the raw synthesis gas into the detoxification tank for reaction. By gradually closing the opening degree of the start-up bypass line valve and slowly opening the front and rear manual valves of the detoxification tank, the gas flow path is smoothly switched. During this process, a part of the cooled shift gas from the shift gas ammonia washing tower is mixed as cold gas to adjust the gas temperature and composition entering the shift converter, thereby inhibiting the rapid temperature rise of the bed. After the operation is stable, the gas is introduced to the downstream device.

[0039] The application realizes smooth commissioning of the detoxification process, effectively controls the exothermic intensity of the hydrogenolysis reaction and the like, and prevents large temperature fluctuations in the catalyst bed. By finely adjusting the amount of cold gas, the detoxification effect is ensured while the accuracy of system heat management is improved, which is conducive to prolonging the service life of the catalyst.

[0040] Further, the method further comprises: The crude synthesis gas is introduced into the first shift converter, the start-up bypass line of the first shift converter is gradually closed, the front and rear hand valves of the first shift converter are opened, and the cooled shift gas in the shift gas ammonia washing tower is introduced as cold gas to prevent the bed temperature from rising too fast. After the temperature stabilizes, the introduction of the cooled shift gas is stopped, and the second shift converter is entered.

[0041] In the above embodiment, the detoxified process gas is also introduced into the first shift converter. By gradually closing the start-up bypass line of the first shift converter and synchronously opening its inlet and outlet valves, the gas flow is switched. In this process, the cooled shift gas is continuously introduced to regulate the inlet gas temperature, and the bed temperature change is closely monitored until it tends to be stable, after which the cold gas injection is stopped, and the gas is introduced into the second shift converter.

[0042] The application makes the commissioning process of the first shift converter smooth and controllable, effectively avoiding bed over-temperature caused by the intense heat release of the CO shift reaction. By adjusting the gas path and the amount of cold gas in stages, the catalyst is ensured to operate within a suitable temperature range, which not only guarantees the conversion efficiency, but also improves the stability of the start-up operation.

[0043] Further, the method further comprises: The shift gas enters the second shift converter, the start-up bypass line of the second shift converter is gradually closed, the front and rear hand valves of the second shift converter are opened, and the cooled shift gas in the shift gas ammonia washing tower is introduced as cold gas to prevent the bed temperature from rising too fast. After the temperature stabilizes, the introduction of the cooled shift gas is stopped.

[0044] In the above embodiment, the gas after the first shift converter reaction is further introduced into the second shift converter. By slowly closing the start-up bypass line valve of the second shift converter and opening its inlet and outlet valves, the commissioning of the final reactor is completed. In this process, the cooled shift gas is introduced as cold gas to control the bed temperature rise rate, and the addition of cold gas is stopped after the temperature stabilizes, thereby completing the entire shift reaction process.

[0045] The application realizes gradual and smooth start-up of multi-stage shift reaction, effectively controls the temperature distribution of each reactor bed. The cold gas is effectively utilized for fine adjustment, and the running stability of the whole system and the qualified rate of synthesis gas quality are improved.

[0046] Further, the method further comprises: The finally obtained shifted gas and unshifted gas are boosted to 5.0-6.5 MPa (G), the hydrogen-carbon ratio is adjusted, and after passing the inspection, the shifted gas and the unshifted gas are sent to downstream devices.

[0047] In the above embodiment, the shifted gas and the unshifted gas generated in the system are respectively adjusted to the required operating pressure. Then, the hydrogen-carbon ratio in the gas is adjusted according to the requirement of the downstream device on the composition of the synthesis gas, and after passing the inspection, the gas can be stably delivered to the downstream device.

[0048] The present application ensures that the output gas meets the requirements of downstream use in terms of pressure and composition, and realizes smooth connection between the gasification device and the downstream device. By actively controlling the key parameters of the gas, the applicability of the product gas and the operation efficiency of the entire production process are significantly improved.

[0049] Referring to Figure 2 , a structure schematic diagram of a coal water slurry gasification device provided by an embodiment of the present application is shown, which comprises: a crude synthesis gas inlet 10; a shift pipeline, the shift pipeline being connected with the crude synthesis gas inlet 10; an unshifted pipeline, the unshifted pipeline being connected with the crude synthesis gas inlet 10; a shifted gas downstream device 83, the shifted gas downstream device 83 being connected with the shift pipeline; an unshifted gas downstream device 101, the unshifted gas downstream device 101 being connected with the unshifted pipeline.

[0050] In the above embodiment, the process of the coal water slurry gasification starts from the crude synthesis gas inlet 10, which receives the high-temperature crude synthesis gas generated by the upstream coal water slurry gasification furnace. Then, the gas flow is divided into two independent process paths at the gas source distribution point. The shift pipeline path aims to increase the hydrogen content in the gas, and the core equipment thereof is a shift reactor, in which CO and water vapor undergo a shift reaction to generate more H2 and CO2. After the reaction, the high-temperature gas is cooled by a heat exchanger, and then the condensed water is removed by a gas-liquid separator, and the shifted gas rich in H2 can be sent to the downstream device. The unshifted pipeline path aims to retain the carbon monoxide content in the gas, and the CO-rich gas of the path is the unshifted gas. Finally, the two processed gases meet the requirements of different devices, such as a methanol synthesis device, a synthetic oil device, an acetic acid device, an ethylene glycol device, etc.

[0051] The present application realizes flexible distribution and efficient utilization of the synthesis gas through the split design of the shifted gas and the unshifted gas, and is a core component of a modern coal chemical industry multi-production system.

[0052] Further, the shift pipeline and the unshifted pipeline comprise: a first gas-liquid separator 20, the first gas-liquid separator 20 being connected with the crude synthesis gas inlet 10; a detoxification tank 30 connected with the first gas-liquid separator 20; a first shift converter 40 connected with the detoxification tank 30; a raw gas heat exchanger 31 connected with the first shift converter 40; a medium-pressure steam superheater 51 connected with the first shift converter 40; a low-pressure steam superheater 52 connected with the medium-pressure steam superheater 51; a medium-pressure steam waste heat boiler 53 connected with the low-pressure steam superheater 52; a second shift converter 50 connected with the medium-pressure steam waste heat boiler 53; a low-pressure steam waste heat boiler 61 connected with the second shift converter 50; a second gas-liquid separator 60 connected with the low-pressure steam waste heat boiler 61; a low-low-pressure steam waste heat boiler 71 connected with the second gas-liquid separator 60; a third gas-liquid separator 70 connected with the low-low-pressure steam waste heat boiler 71; a desalted water heat exchanger 81 connected with the third gas-liquid separator 70; a circulating water cooler 82 connected with the desalted water heat exchanger 81; a shift gas ammonia washing tower 80 connected with the circulating water cooler 82; a shift gas high-pressure hydrogen-rich flare 85 connected with the shift gas ammonia washing tower 80; an unshifted gas ammonia washing tower 100 connected with the crude synthetic gas inlet 10; an unshifted gas high-pressure hydrogen-rich flare 103 connected with the unshifted gas ammonia washing tower 100.

[0053] In the above embodiment, after the crude synthesis gas enters from the inlet, it is divided into a shift pipeline and an unshifted pipeline. The shift pipeline is sequentially connected with a first gas-liquid separator, a detoxification tank, a first shift furnace, a raw gas heat exchanger, a medium-pressure steam superheater, a low-pressure steam superheater, a medium-pressure steam waste heat boiler, a second shift furnace, a low-pressure steam waste heat boiler, a second gas-liquid separator, a low-low-pressure steam waste heat boiler, a third gas-liquid separator, a desalted water heat exchanger, a circulating water cooler, a shift gas ammonia washing tower, and is provided with a shift gas high-pressure hydrogen-rich torch. The unshifted pipeline is connected with an unshifted gas ammonia washing tower, and is provided with an unshifted gas high-pressure hydrogen-rich torch. This connection relationship ensures that the crude synthesis gas can be effectively treated, the shifted and unshifted parts are separated, and through a series of heat exchangers and reactors, energy recovery and process requirements are realized.

[0054] The present application divides the crude synthesis gas through the shift pipeline and the unshifted pipeline, and the crude synthesis gas is reasonably divided, the shifted part is subjected to multi-stage shift and heat recovery, and the energy utilization efficiency is improved, while the unshifted part is directly treated, and the process is simplified. The whole structure optimizes the reaction conditions, ensures the stability and safety during start-up, and lays a foundation for subsequent injection of cooling gas to control the temperature.

[0055] Further, the device further comprises: The injection points include a first injection point 32 arranged at the inlet of the detoxification tank 30, a second injection point 41 arranged at the inlet of the first shift furnace 40, and a third injection point 54 arranged at the inlet of the second shift furnace 50; The booster 110 is connected with the shift gas ammonia washing tower 80, and is used for pressurizing the shift gas and conveying the shift gas to the first injection point 32, the second injection point 41 and the third injection point 54.

[0056] In the above embodiment, the present application is provided with multiple injection points, the first injection point is located at the inlet of the detoxification tank, the second injection point is located at the inlet of the first shift furnace, and the third injection point is located at the inlet of the second shift furnace. The booster is connected with the shift gas ammonia washing tower, and is used for conveying the cooled shift gas to these injection points after pressurization. This connection relationship allows the cooled shift gas to be injected into the key devices during start-up, so as to adjust the composition and temperature of the entering gas. The whole device of the present application includes a crude synthesis gas inlet, a shift pipeline, an unshifted pipeline, a downstream device, and injection points and a booster. The shift pipeline and the unshifted pipeline respectively treat the crude synthesis gas, and realize gas treatment and energy recovery through a series of heat exchangers, separators and reactors. The injection points and the booster are integrated into the system, and are used for injecting the cooled shift gas as a cold shock gas during the start-up stage. This comprehensive design ensures that the device can comprehensively control the temperature during the first start-up.

[0057] The application can reduce the concentration of carbon monoxide in the crude synthesis gas, reduce the intensity of the shift reaction, inhibit the rapid rise of the catalyst bed temperature, and prevent the over-temperature phenomenon by injecting the cooled shift gas. The supercharger ensures that the shift gas can be injected at the required pressure, effectively controls the temperature fluctuation, prolongs the service life of the catalyst and equipment, and improves the safety and reliability of the starting process. The application effectively controls the catalyst bed temperature by injecting the cooled shift gas as a cold shock gas at the key point, prevents over-temperature during the first start, thereby prolonging the service life of the catalyst and equipment and improving safety. At the same time, the structure design is simplified, energy recovery is efficient, stable operation is ensured, and the process requirements in the field of coal chemical methanol technology are met.

[0058] The crude synthesis gas 10, 3.0-6.5 MPa (G), 200-240℃, enters the shift process, and is divided into a shifted part and an unshifted part. The shifted part is shifted to produce hydrogen, and the hydrogen-carbon ratio is adjusted by the unshifted part. The shifted part first enters a first gas-liquid separator 20, and the separated condensate is referred to as high-temperature condensate 21. The gas phase after separation passes through a raw gas heat exchanger and enters a detoxification tank 30. The crude synthesis gas after the detoxification tank enters a first shift furnace 40 to perform a shift reaction. The temperature after the reaction is 420-440℃. The shifted gas after the first shift furnace enters the raw gas heat exchanger 31 and the medium-pressure steam superheater 51 and the low-pressure steam superheater 52 to produce 420℃ medium-pressure superheated steam and 280℃ low-pressure superheated steam. The two streams of shifted gas are mixed and enter a medium-pressure steam waste heat boiler 53 to produce medium-pressure saturated steam. The shifted gas after the medium-pressure steam waste heat boiler enters a second shift furnace 50 to further perform a shift reaction. The bed temperature after the second shift furnace is 270-300℃. The shifted gas after the second shift furnace enters a low-pressure steam waste heat boiler 61 to produce low-pressure saturated steam, and then enters a second gas-liquid separator. The separated condensate is referred to as high-temperature condensate 62. The gas phase passes through a low-low-pressure steam waste heat boiler 71 to produce low-low-pressure steam, and then enters a third gas-liquid separator. The separated condensate is referred to as high-temperature condensate 72. The gas phase passes through a desalted water heat exchanger 81 and a circulating water cooler 82, enters an ammonia washing tower 80, and the shifted gas at the top of the tower is at a temperature of 40℃ and is sent to a downstream device 83. The condensate at the bottom of the tower is referred to as low-temperature condensate 84. The ammonia washing tower of the shifted gas is provided with a high-pressure hydrogen-rich flare 85 for easy use during start-up. The shifted part after the shift process 90 enters the ammonia washing tower 100 of the shifted gas. The unshifted gas at the top of the tower is at a temperature of 40℃ and is sent to a downstream device 101. The condensate at the bottom of the tower is referred to as low-temperature condensate 102. The ammonia washing tower of the unshifted gas is provided with a high-pressure hydrogen-rich flare 103 for easy use during start-up. The high-temperature condensates 21, 62 and 72 enter a downstream condensate treatment device. The low-temperature condensates 84 and 102 enter a downstream condensate treatment device. The ammonia washing tower of the shifted gas is provided with a booster 110 to increase the pressure to be higher than that of the crude synthesis gas. After boosting, the temperature of the shifted gas increases by 5-40℃, and then is sent to the first injection point, the second injection point and the third injection point of the detoxification tank, the first shift furnace and the second shift furnace. The detoxification tank, the first shift furnace and the second shift furnace are each provided with a start-up auxiliary line.

[0059] The start-up process is described as follows: After the first time the catalyst is loaded in the detoxification tank, the first shift furnace and the second shift furnace, the start-up process is divided into six stages: In the first stage, nitrogen is used to heat the detoxification tank, the first shift furnace and the second shift furnace to 220-300℃. After heating, the nitrogen is cut off, and the detoxification tank, the first shift furnace and the second shift furnace are all closed and isolated by opening and closing the front and rear valves.

[0060] The second stage is to introduce the crude synthesis gas to the detoxification tank, the first shift converter and the second shift converter to warm the pipes and equipment in the shift section, and to send the shift gas to the high-pressure hydrogen-rich torch after washing the ammonia tower.

[0061] The third stage is to introduce the crude synthesis gas into the detoxification tank. Before introducing the crude synthesis gas, the start-up auxiliary line of the detoxification tank is gradually closed, the front and rear hand valves of the detoxification tank are opened, the crude synthesis gas enters the detoxification tank, the adsorption heat generated causes the bed temperature of the detoxification tank to rise, the top shift gas of the ammonia tower is introduced as cooling gas, the flow rate is adjusted to prevent the bed temperature from rising too fast, and after the temperature rises to the peak and then decreases and gradually stabilizes, the first shift converter is entered. In this stage, the cooled gas is used to cool the detoxification tank without passing through the shift converter. This step can also be performed after the second shift converter in the fifth stage.

[0062] The fourth stage is to enter the first shift converter. The start-up auxiliary line of the first shift converter is gradually closed, the front and rear hand valves of the first shift converter are opened, the crude synthesis gas enters the first shift converter, and the adsorption heat and reaction heat generated when the crude synthesis gas passes through the first shift converter cause the bed temperature of the first shift converter to rise rapidly. The cooled shift gas is introduced as cooling gas, the flow rate is adjusted to prevent the bed temperature from rising too fast, and after the temperature rises to the peak and then decreases and gradually stabilizes, the cooled shift gas is stopped and the second shift converter is entered. The introduction point in this stage can also be adjusted by the cooled shift gas before the third stage of the detoxification tank.

[0063] The fifth stage is to enter the second shift converter. The start-up auxiliary line of the second shift converter is gradually closed, the front and rear hand valves of the second shift converter are opened, and the shift gas enters the second shift converter. The adsorption heat and reaction heat generated cause the bed temperature of the second shift converter to rise rapidly, the cooled shift gas is introduced as cooling gas, the flow rate is adjusted to prevent the bed temperature from rising too fast, and after the temperature rises to the peak and then decreases and gradually stabilizes, the cooled shift gas is stopped.

[0064] The sixth stage is the system pressure increasing and hydrogen to carbon ratio adjusting stage, in which the shift section and the unshifted section are pressurized to 5.0-6.5 MPa (G), and the appropriate hydrogen to carbon ratio is adjusted. After the hydrogen to carbon ratio is qualified, it is sent to the downstream device.

[0065] The present application has the following characteristics: (1) The crude synthesis gas is introduced at a pressure of 3.0-6.5 MPa (G), which can avoid the situation that the water to gas ratio is low when the pressure is low, and the heat generated cannot be removed in time.

[0066] (2) After the cooled shift gas is introduced, the CO concentration in the crude synthesis gas is reduced, and the intensity of the shift reaction is reduced.

[0067] (3) The cooled shift gas components occupy the active sites of the shift catalyst, to some extent, inhibit the occurrence of the shift reaction, slow down the heat effect generated when the crude synthesis gas is introduced, and inhibit the rapid rise of the temperature.

[0068] (4) Since the cooled shift gas is used as the cooling and temperature reducing medium, no other medium is introduced, the bed temperature can be conveniently reduced by adjusting the amount of the introduced cooled shift gas, and the rapid rise of the bed temperature after the shift catalyst is loaded is prevented.

[0069] (5) When the cooled shift gas is introduced into the detoxification tank as the cooling gas, the rapid rise of the bed temperature is prevented by adjusting the cooling flow, so that the bed temperature of the detoxification tank is reduced from 400 DEG C when no cooled shift gas is introduced to the normal temperature of 280 DEG C, and the temperature reduction is up to 120 DEG C.

[0070] (6) When the cooled shift gas is introduced into the first shift converter as the cooling gas, the rapid rise of the bed temperature is prevented by adjusting the flow, so that the bed temperature of the first shift converter is reduced from 505 DEG C when no cooled shift gas is introduced to the normal temperature of 430 DEG C, and the temperature reduction is up to 75 DEG C.

[0071] (7) When the cooled shift gas is introduced into the second shift converter as the cooling gas, the rapid rise of the bed temperature is prevented by adjusting the flow, so that the bed temperature of the second shift converter is reduced from 370 DEG C when no cooled shift gas is introduced to the normal temperature of 290 DEG C, and the temperature reduction is up to 80 DEG C.

[0072] The water coal slurry gasification method and device provided by the application include the following steps: in the first start-up process of the water coal slurry gasification, the cooled shift gas is introduced into at least one of the detoxification tank, the first shift converter and the second shift converter as the cooling gas to control the bed temperature of the catalyst, and the introduction of the cooled shift gas is stopped after the bed temperature is stabilized. In the first start-up process of the water coal slurry gasification, the cooled shift gas from the shift gas ammonia washing tower is introduced into the detoxification tank, the first shift converter and the second shift converter in sequence, the low-temperature characteristics of the cooled shift gas are used to directly absorb the heat of the bed reaction, and the concentration of the reaction components in the crude synthesis gas is diluted, so that the temperature rise speed is effectively inhibited in the initial adsorption and reaction heat release stage of the catalyst. The main and auxiliary lines are switched gradually, the flow of the cooling gas is adjusted, the precise control of the bed temperatures of the multiple reactors is realized, the catalyst sintering and deactivation and the equipment damage caused by the heat accumulation in the traditional way are avoided, and the safety and the operation stability of the start-up process are significantly improved.

[0073] Those skilled in the art can understand that the modules or flows in the drawings are not necessarily required for implementing the present application. Those skilled in the art can understand that the modules in the devices in the implementation scenarios can be distributed in the devices in the implementation scenarios according to the description of the implementation scenarios, or can be changed to be located in one or more devices different from the implementation scenarios. The modules in the above implementation scenarios can be combined into one module, or can be further split into multiple sub-modules.

[0074] The above application numbers are only for description, and do not represent the advantages and disadvantages of the implementation scenarios. The above disclosure is only some specific implementation scenarios of the present application, but the present application is not limited thereto, and any variations that can be thought of by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A method for gasifying coal-water slurry, characterized in that, include: During the initial start-up of coal-water slurry gasification, cooled shift gas is introduced into at least one of the detoxification tank, the first shift reactor, and the second shift reactor as quench gas to control the catalyst bed temperature. Once the bed temperature stabilizes, the introduction of cooled shift gas is stopped.

2. The method according to claim 1, characterized in that, The method further includes: The detoxification tank, the first converter, and the second converter are heated to 220-300℃ using nitrogen gas. After the heating is completed, the nitrogen gas is cut off and the detoxification tank, the first converter, and the second converter are isolated.

3. The method according to claim 2, characterized in that, The method further includes: The crude syngas is introduced through the detoxification tank, the start-up auxiliary line of the first and second converters to warm up the conversion pipeline and the unconverted pipeline to 150-220°C. The conversion gas passes through the conversion gas ammonia scrubbing tower to the high-pressure hydrogen-rich flare, and the unconverted gas passes through the unconverted gas ammonia scrubbing tower to the high-pressure hydrogen-rich flare.

4. The method according to claim 3, characterized in that, The method further includes: The crude syngas is introduced into the detoxification tank. The detoxification tank start-up auxiliary line is gradually closed, and the front and rear hand valves of the detoxification tank are opened. The cooled shift gas in the shift gas washing tower is introduced as the cold quench gas. The flow rate is adjusted to prevent the bed temperature from rising too quickly. After the temperature stabilizes, it enters the first shift furnace.

5. The method according to claim 4, characterized in that, The method further includes: The crude syngas is introduced into the first converter. The start-up auxiliary line of the first converter is gradually closed. The manual valves before and after the first converter are opened. The converted gas cooled in the ammonia washing tower is introduced as quench gas. The flow rate is adjusted to prevent the bed temperature from rising too quickly. After the temperature stabilizes, the introduction of the cooled converted gas is stopped and the gas enters the second converter.

6. The method according to claim 5, characterized in that, The method further includes: The shift gas enters the second shift furnace. The second shift furnace start-up auxiliary line is gradually closed. The front and rear manual valves of the second shift furnace are opened. The shift gas cooled in the shift gas washing tower is introduced as cold quench gas. The flow rate is adjusted to prevent the bed temperature from rising too quickly. After the temperature stabilizes, the introduction of cooled shift gas is stopped.

7. The method according to claim 6, characterized in that, The method further includes: The final obtained shift gas and unshifted gas are pressurized to 5.0-6.5 MPa(G), the hydrogen-carbon ratio is adjusted, and after passing the test, they are sent to downstream units.

8. A coal-water slurry gasification device, characterized in that, include: crude syngas inlet (10); A conversion pipeline is connected to the crude syngas inlet (10); Unchanged pipeline, which is connected to the crude syngas inlet (10); Downstream device (83) for switching gas, which is connected to the switching pipeline; Unchanged gas downstream device (101), which is connected to the unchanged pipeline.

9. The apparatus according to claim 8, characterized in that, The transformed pipeline and the untransformed pipeline include: A first gas-liquid separator (20) is connected to the crude syngas inlet (10); Detoxification tank (30), which is connected to the first gas-liquid separator (20); The first converter (40) is connected to the detoxification tank (30); Raw material gas heat exchanger (31), which is connected to the first converter (40); A medium-pressure steam superheater (51) is connected to the first converter (40); A low-pressure steam superheater (52) is connected to the medium-pressure steam superheater (51); A medium-pressure steam waste boiler (53) is connected to the low-pressure steam superheater (52); The second converter (50) is connected to the medium-pressure steam waste boiler (53); A low-pressure steam waste boiler (61) is connected to the second converter (50); The second gas-liquid separator (60) is connected to the low-pressure steam waste boiler (61); Low-pressure steam waste boiler (71), which is connected to the second gas-liquid separator (60); The third gas-liquid separator (70) is connected to the low-pressure steam waste boiler (71); A demineralized water heat exchanger (81) is connected to the third gas-liquid separator (70); A circulating water cooler (82) is connected to the demineralized water preheater (81); A shift gas scrubbing ammonia tower (80) is connected to the circulating water cooler (82); A high-pressure hydrogen-rich flare (85) for shift gas is connected to the ammonia scrubbing tower (80) for shift gas. An unconverted gas scrubbing ammonia tower (100) is connected to the crude syngas inlet (10); A high-pressure hydrogen-rich flare (103) for unconverted gas is connected to the ammonia scrubbing tower (100) for unconverted gas.

10. The apparatus according to claim 9, characterized in that, The device further includes: The injection points include a first injection point (32) located at the inlet of the detoxification tank (30), a second injection point (41) located at the inlet of the first converter (40), and a third injection point (54) located at the inlet of the second converter (50). A booster (110) is connected to the shift gas ammonia scrubbing tower (80) and is used to boost the shift gas and deliver it to the first injection point (32), the second injection point (41) and the third injection point (54).

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