Biomass synthesis gas shift process with gradient distribution of catalyst

Abstract

The invention discloses a catalyst gradient distribution biomass synthesis gas shift process, which comprises the following steps of: performing heat exchange on biomass synthesis gas and high-temperature shift gas through a gas-gas heat exchanger, mixing with steam, entering a shift reactor, performing CO shift reaction, entering the output high-temperature shift gas into the gas-gas heat exchanger, performing heat exchange on the output high-temperature shift gas and the biomass synthesis gas, and performing catalyst gradient distribution on the output high-temperature shift gas. And the exchange gas is output. The multi-layer catalyst bed adopts an activity enhanced sulfur-tolerant shift catalyst and is arranged in a gradient layering manner along the axial direction, so that the anti-poisoning capability of the catalyst on tar and sulfide in synthesis gas is remarkably enhanced, meanwhile, heat released by water gas shift reaction can be efficiently removed, the axial and radial temperature gradients of the catalyst bed layer are accurately controlled, and the stability of the catalyst bed layer is improved. Catalyst sintering caused by local overtemperature is avoided, meanwhile, a hot spot area is eliminated, and side reactions such as methanation are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass syngas shift process, and particularly relates to a biomass syngas shift process with catalyst gradient distribution. BACKGROUND

[0002] As a renewable carbon resource conversion carrier, biomass syngas is converted from agricultural and forestry wastes or fermentation residues (biogas residues) through biomass pyrolysis and gasification technology, and is mainly composed of CO and H2, accompanied by CO2, CH4, tar, sulfides (H2S / COS, etc.), dust and other complex components.

[0003] Among them, the water gas shift reaction (WGS) is a key link for regulating the molar ratio of H2 / CO, which directly determines the production efficiency and economy of subsequent syngas (such as methanol, Fischer-Tropsch synthesis oil, dimethyl ether, etc.) or hydrogen energy. However, the shift process still faces some problems in industrial application:

[0004] The traditional single catalyst bed shift reactor adopts a fixed gas flow channel design, and the catalyst bed has weak resistance to impurities. The tar in the syngas will cover the active sites of the catalyst, and H2S will easily react with the active metal components (such as Cu) of the catalyst to form CuS, causing catalyst poisoning, which reduces the activity of the catalyst or even deactivates the catalyst. The water gas shift reaction is a strong exothermic reaction, and 41.2 kJ of heat is released for every 1 mol of CO in the system in an adiabatic shift reactor. Under the condition of high CO concentration and high CO conversion rate, the axial and radial temperature gradients of the shift reactor are easy to be out of control, exceeding the temperature resistance limit of the catalyst, causing the catalyst in the local area to sinter and reducing the activity of the catalyst; at the same time, the temperature difference between the center area and the pipe wall area of the reactor is large, forming a "hot spot" area, which triggers the side reaction (such as methanation reaction: CO+3H2→CH4+H2O), which is not conducive to the control operation of the hydrogen-carbon ratio of the syngas.

[0005] In the existing related technologies, for example, patent document CN103449365B proposes a sulfur-tolerant two-stage shift process, which is aimed at a high-concentration CO shift system, solves the problems of overheating and overtemperature, reduces the risk of methanation reaction, and reduces the impact of production load changes on the shift reaction process. For example, patent document CN101721956A proposes an isothermal low-temperature CO shift reactor, which can remove the reaction heat in time during the reaction to maintain the reaction at a low temperature and constant temperature, and solve the problem of local overheating of the reactor and burning out of the catalyst. However, these technologies still have obvious limitations when dealing with the challenges of biomass syngas water gas shift, such as difficulty in adapting to large fluctuations in biomass syngas components, limited gas treatment capacity, the need for a high-precision desulfurization unit, dynamic control lag, low system integration, long process, many equipment, and difficulty in hydrogen-carbon ratio control operation.

[0006] Therefore, a biomass syngas shift process system is needed, which can adapt to the fluctuation characteristics of biomass syngas components, improve the resistance to impurities and wide temperature range activity through the gradient distribution of composite catalysts, and combine the precise temperature control of layered shell-and-tube reactor design to avoid local overheating and catalyst sintering. At the same time, a dynamic gas control system is integrated to adjust the gas flow and hydrogen-carbon ratio in real time, shorten the process and reduce the equipment, enhance the system integration and control flexibility, thereby efficiently solving the problems of catalyst poisoning, reaction heat control and complex operation in the prior art, and providing stable raw gas for subsequent synthesis process or hydrogen energy production. SUMMARY

[0007] In view of the above problems, the purpose of the present application is to provide a biomass syngas shift process with catalyst gradient distribution, which solves the problems of catalyst poisoning, reaction heat control and complex operation in the biomass syngas shift process of the prior art.

[0008] The purpose of the present application can be achieved by the following technical solution: a biomass syngas shift process with catalyst gradient distribution, comprising:

[0009] The biomass syngas and high-temperature shift gas are heat exchanged through a gas-gas heat exchanger, mixed with steam, and then enter a shift reactor for CO shift reaction. The output high-temperature shift gas is heat exchanged with the biomass syngas through the gas-gas heat exchanger and then output as exchange gas.

[0010] As a further embodiment of the present application, the catalyst beds are arranged in layers along the axial direction in the shift reactor, and the multiple layers of catalyst beds all use active enhanced sulfur-tolerant shift catalysts and are arranged in gradient layers along the axial direction.

[0011] As a further embodiment of the present application, each layer of catalyst bed adopts a tube-and-shell heat exchanger structure, wherein the tube side is filled with active enhanced sulfur-tolerant shift catalysts in a honeycomb shape, and the shell side is filled with saturated hot water.

[0012] As a further embodiment of the present application, a corresponding gas flow distributor is further arranged below each layer of catalyst bed, the balanced gas flow holes distributed on the gas flow distributor are in a honeycomb shape, and balanced fan blades are arranged in the balanced gas flow holes.

[0013] As a further embodiment of the present application, a steam inlet flow meter and a steam inlet flow control valve are arranged on the steam pipeline along the gas flow direction, a syngas inlet flow meter is arranged on the biomass syngas inlet pipeline before being connected to the steam pipeline, and the syngas inlet flow meter and the steam inlet flow control valve are linked.

[0014] The biomass synthesis gas inlet pipeline is connected with the shift reactor outlet pipeline, and an H2 / CO ratio regulating valve is arranged before the connection, and an H2 / CO ratio monitoring instrument is arranged after the connection, and the H2 / CO ratio monitoring instrument is linked with the H2 / CO ratio regulating valve.

[0015] As a further aspect of the present application, the biomass synthesis gas inlet branch pipeline is connected between the catalyst beds of each layer and below the gas distributor.

[0016] As a further aspect of the present application, part of the heat generated by the CO shift reaction of the catalyst bed is recovered by a heat recovery system and utilized.

[0017] As a further aspect of the present application, the heat recovery system comprises: saturated hot water in a steam drum is transported into the catalyst bed by a hot water circulating pump, and steam is generated after heat exchange with the heat generated by the CO shift reaction, the steam returns to the steam drum for gas-liquid separation, the steam is exported as a product or used by itself, and the saturated hot water is continuously circulated by the hot water circulating pump, wherein the steam drum is connected with a water supplement pipeline.

[0018] A biomass synthesis gas shift device with gradient distribution of catalysts comprises:

[0019] A shift reactor with multiple layers of catalyst beds arranged in an axial gradient for CO shift reaction of mixed steam biomass synthesis gas;

[0020] A gas-gas heat exchanger for heat exchange between high-temperature shift gas output by the shift reactor and biomass synthesis gas;

[0021] A steam heat exchange assembly for heat exchange and recycling of heat generated by the CO shift reaction.

[0022] As a further aspect of the present application, the steam heat exchange assembly comprises:

[0023] A steam drum for gas-liquid separation of the steam recovered from heat, the steam is exported as a product or used by itself, and the saturated hot water is continuously circulated;

[0024] A hot water circulating pump for transporting saturated hot water in the steam drum into the catalyst bed by the hot water circulating pump, and generating steam after heat exchange with the heat generated by the CO shift reaction.

[0025] The present application has the following beneficial effects:

[0026] 1. The present application proposes a gradient distribution of composite catalyst bed with good activity in a wide temperature range of shift reaction, and good resistance to sulfur poisoning; at the same time, the shift reactor is designed in layers and shell-and-tube catalyst bed, and the catalyst axial and radial temperature is precisely controlled by using saturated hot water, which avoids the sintering of catalyst caused by local over-temperature in the axial and radial direction of the catalyst bed; finally, the reaction temperature and gas flow condition of biomass synthesis gas are dynamically regulated by gas distributor and temperature gas control valve, which ensures the precise regulation of hydrogen-carbon ratio of biomass synthesis gas.

[0027] 2. Each catalyst bed of the present application is designed by referring to the shell-and-tube heat exchanger, the catalyst is filled in the tube, and the saturated hot water is introduced into the shell, which can efficiently remove the heat released by the water-gas shift reaction, precisely control the axial and radial temperature gradient of the catalyst bed, avoid the sintering of catalyst caused by local over-temperature, and eliminate the hot spot area to reduce the occurrence of side reactions such as methanation.

[0028] 3. The gas flow distributor at the inlet of each catalyst bed layer of the present application can stabilize the gas flow state of biomass synthesis gas and ensure uniform gas contact with the catalyst; in combination with the regulation of the outlet gas flow temperature and distribution of the first and second temperature gas flow control valves, the uniformity and stability of the reaction are further improved, which provides good conditions for efficient shift, optimizes the dynamic distribution of gas flow, and ensures the uniformity of the reaction.

[0029] 4. The steam inlet flow control valve and the steam inlet flow meter of the present application are linked to dynamically control the flow ratio of synthesis gas and steam, realize precise regulation of the progress and temperature of shift reaction, and the H2 / CO ratio monitor at the outlet of the shift reactor forms a closed loop control with the control valve, which can real-time correct the hydrogen-carbon ratio of shift gas, greatly reduce the operation difficulty, and ensure that the product meets the process requirements of subsequent synthesis (such as methanol, Fischer-Tropsch synthesis oil) or hydrogen energy production. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structure diagram of the catalyst gradient distribution biomass synthesis gas shift process of the present application;

[0031] Figure 2 It is a top view schematic diagram of the catalyst bed and gas distributor of the present application.

[0032] 01, synthesis gas into tower flow meter; 02, steam into tower flow control valve; 03, steam into tower flow meter; 04, first temperature gas flow control valve; 05, second temperature gas flow control valve; 06, H2 / CO ratio control valve; 07, H2 / CO ratio monitor; 11, shift reactor; 12, first gas flow distributor; 13, first catalyst bed; 14, second gas flow distributor; 15, second catalyst bed; 16, third gas flow distributor; 17, third catalyst bed; 21, gas-gas heat exchanger; 31, steam drum; 41, hot water circulating pump. DETAILED DESCRIPTION

[0033] Embodiments of the present application are described in detail below with reference to the attached drawings, which show by way of example, embodiments in which like numerals indicate like elements or elements having the same or similar function throughout the several views. The embodiments described below are exemplary only, and are not to be construed as limiting the present application.

[0034] The existing process device has the following problems: unreasonable catalyst distribution, insufficient gas flow regulation capacity, insufficient gas flow and catalyst contact, low heat utilization efficiency, insufficient waste heat recovery rate, resulting in high operation and maintenance cost.

[0035] In view of the above problems, the present application discloses a biomass synthesis gas shift process device with gradient distribution of catalyst.

[0036] Embodiment 1

[0037] The present embodiment discloses a biomass synthesis gas shift process with gradient distribution of catalyst, as shown in Figure 1

[0038] The biomass synthesis gas enters the gas-gas heat exchanger 21 along the gas inlet pipeline, exchanges heat with the high-temperature shift gas in the gas-gas heat exchanger 21, and the heat of the high-temperature shift gas is partially exchanged with the biomass synthesis gas, so that the temperature of the biomass synthesis gas is raised, which is beneficial to the efficient performance of the subsequent shift reaction.

[0039] The biomass synthesis gas after being heated is divided along the pipeline, a part of the biomass synthesis gas is combined with the steam precisely controlled by the steam into tower flow control valve 02 and the steam into tower flow meter 03 after being monitored by the synthesis gas into tower flow meter 01, and enters the shift reactor 11 from the bottom of the shift reactor 11.

[0040] Preferably, the synthesis gas into tower flow meter 01 is linked with the steam into tower flow control valve 02 to control the mixing ratio of the biomass synthesis gas and the steam, and to ensure that the H2O / CO molar ratio in the raw material gas entering the shift reactor 11 is stable in the optimal reaction range.

[0041] ​The linkage control mechanism can accurately match the demand of the shift reaction for water vapor ratio, provide stable initial conditions for the gradient reaction of the subsequent catalyst bed, and effectively improve the adaptability of the system to the fluctuation of the raw material gas.

[0042] The biomass synthesis gas mixed with steam enters the shift reactor 11 for CO shift reaction. The high-temperature shift gas at the outlet of the shift reactor 11 is sent to the gas-gas heat exchanger 21 along the pipeline, and after heat recovery by heat exchange with the biomass synthesis gas, the shift reaction is completed, and the shift gas is output.

[0043] Preferably, the biomass synthesis gas inlet pipeline is provided with an H2 / CO ratio control valve 06 before the outlet pipeline of the shift reactor 11, and an H2 / CO ratio monitor 07 after the outlet pipeline of the shift reactor 11 is connected to the biomass synthesis gas inlet pipeline, and the H2 / CO ratio monitor 07 is linked with the H2 / CO ratio control valve 06.

[0044] When the H2 / CO ratio monitor 07 detects that the H2 / CO ratio in the outlet pipeline of the shift reactor 11 deviates from the preset optimal ratio range, it can timely feedback the signal to the H2 / CO ratio control valve 06. The H2 / CO ratio control valve 06 accurately adjusts the flow of biomass synthesis gas according to the received feedback signal. This linkage mechanism can accurately control the H2 / CO ratio in the shift reaction process in real time and dynamically, ensuring that the entire biomass synthesis gas shift process is always carried out under the optimal gas ratio conditions.

[0045] By using the above process, the heat of the high-temperature shift gas is partially recovered and utilized, and the mixing ratio of the biomass synthesis gas and steam is regulated, improving the energy utilization efficiency and the stability of the reaction.

[0046] Example 2:

[0047] Based on Example 1, this embodiment discloses a biomass synthesis gas shift process with catalyst gradient distribution, which refines the structure and process of the shift reactor 11, as shown in Figure 1 .

[0048] The first catalyst bed 13, the second catalyst bed 15, and the third catalyst bed 17 are sequentially arranged along the axial direction from the bottom to the top of the shift reactor 11.

[0049] Preferably, as shown in Figure 1 , each layer of catalyst bed uses an active enhanced sulfur-tolerant shift catalyst, and is arranged in a gradient layer along the axial direction.

[0050] The activity-enhanced sulfur-tolerant shift catalyst has good catalytic activity and sulfur resistance, and can efficiently promote the shift reaction in the presence of sulfur-containing biomass synthesis gas. The axial gradient layering arrangement allows the catalysts in different bed layers to have different performance characteristics to meet the needs of different stages of the shift reaction process. From the bottom to the top, the proportion of active components and the temperature resistance of the catalyst can be gradually adjusted to adapt to the changes in gas composition and temperature during the reaction process.

[0051] For example, in the first catalyst bed 13 at the bottom, the activity of the catalyst can be relatively low, but has strong sulfur and impurity resistance, and can preliminarily process biomass synthesis gas containing high sulfur content and impurities to create favorable conditions for subsequent reactions. As the reaction proceeds, in the second catalyst bed 15, the activity of the catalyst gradually increases to further promote the shift reaction of carbon monoxide and steam and increase the production of hydrogen. In the third catalyst bed 17 at the top, the activity of the catalyst reaches the highest, which can maximize the reaction to generate hydrogen and ensure the efficient completion of the shift reaction.

[0052] Through such gradient layering arrangement, not only the performance of the catalyst can be fully utilized to improve the reaction efficiency, but also the catalyst loss and poisoning phenomenon can be reduced. Because the catalysts in different bed layers can be designed and used according to the reaction conditions and gas composition at their positions, the single catalyst is avoided to face complex working conditions in the entire reaction process, thereby prolonging the service life of the catalyst and reducing the production cost.

[0053] Further, each layer of catalyst bed adopts a tube-in-shell heat exchanger structure, in which the tube side is filled with activity-enhanced sulfur-tolerant shift catalyst in a honeycomb shape, and the shell side is filled with saturated hot water, avoiding sintering of the catalyst bed due to local overheating, ensuring the activity and service life of the catalyst. The stability and adaptability of the reaction are improved. The saturated hot water circulates in the shell side to carry away the heat generated during the reaction, so that the temperature of the catalyst bed can be maintained within a suitable range.

[0054] The tube-in-shell heat exchanger structure has good heat transfer performance, which can quickly and effectively transfer the reaction heat to the saturated hot water, further improving the energy utilization efficiency. At the same time, the axial gradient layering arrangement allows the catalyst to achieve the best catalytic effect according to the progress and needs of the reaction.

[0055] In addition, the structure design is also convenient for catalyst replacement and maintenance. When the activity of the catalyst decreases to a certain extent, the catalyst in the tube can be conveniently replaced, without affecting the normal operation of the entire shift reactor 11. Moreover, the saturated hot water system in the shell is easy to check and maintain, ensuring the reliability and stability of the entire process. In this way, production costs can be effectively reduced and production efficiency can be improved.

[0056] Preferably, as shown in Figure 1 and Figure 2 Each layer of catalyst bed is also provided with a corresponding gas flow distributor below, and the balanced gas flow holes on the gas flow distributor are in a honeycomb shape, and the balanced fan blades are arranged in the balanced gas flow holes.

[0057] The biomass synthesis gas enters the bottom of the shift reactor 11 and sequentially passes through the first gas flow distributor 12, the first catalyst bed 13, the second gas flow distributor 14, the second catalyst bed 15, the third gas flow distributor 16, and the third catalyst bed 17 to complete the CO shift reaction.

[0058] In this process, the balanced fan blades of each layer of gas flow distributor can effectively balance the gas flow and adjust the direction of the biomass synthesis gas, so that the mixed gas can be more uniformly contacted with the catalyst bed.

[0059] Preferably, as shown in Figure 1 Some of the biomass synthesis gas is introduced between the catalyst beds along the gas inlet pipeline, and the pipeline inlet is located below the gas flow distributor, which is controlled by the first temperature gas flow control valve 04 and the second temperature gas flow control valve 05.

[0060] Because the reaction degree and temperature of different catalyst beds are different, the introduction of part of the biomass synthesis gas can timely supplement the reactants and maintain the efficient progress of the reaction. Moreover, this mixing method can avoid the occurrence of local high temperature, making the entire reaction process more stable. The newly introduced biomass synthesis gas is fully mixed with the synthesis gas passing through the first catalyst bed 13 below the gas flow distributor, and with the help of the gas flow distributor, the mixed gas flows more uniformly to the subsequent catalyst bed. This not only improves the utilization rate of the catalyst, but also effectively reduces the occurrence of side reactions, thereby improving the selectivity of the synthesis gas shift reaction and the purity of the product.

[0061] The above process structure can arrange catalysts with different activities and selectivities according to specific gradients in terms of gradient distribution of composite catalysts, so that the reaction can fully utilize the characteristics of the catalysts at different stages. At the same time, a special-shaped gas flow distributor is arranged inside the reaction device to guide the gas to form a specific flow pattern, so that the gas can fully contact with the catalysts and improve the reaction efficiency. At the same time, the flow and flow rate of the gas are dynamically adjusted according to the real-time progress of the reaction and the generation of the products, to ensure that the reaction is always in the best state. The gradient distribution of the catalysts and the dynamic regulation of the gas flow cooperate with each other to effectively cope with fluctuations in the composition of the raw gas and the reaction conditions.

[0062] Example 3

[0063] This example discloses a catalyst gradient distribution biomass synthesis gas shift process based on example 1 or 2, as shown in Figure 1 The process uses a heat recovery system to exchange and recycle the heat generated by the CO shift reaction.

[0064] As shown in Figure 1 The saturated hot water in the steam drum 31 is transported into the catalyst bed by the hot water circulating pump 41, exchanges heat with the heat generated by the CO shift reaction to generate steam, the steam returns to the steam drum 31 for gas-liquid separation, the steam is used as a product or self-use, and the saturated hot water continues to circulate. The steam drum 31 is connected with a water supplement pipeline.

[0065] In the heat recovery process, the saturated hot water absorbs heat in the catalyst bed, so that the heat energy generated by the CO shift reaction is fully utilized. During the entire circulation process, the hot water circulating pump 41 ensures that the saturated hot water can continuously and stably flow in the system, maintaining efficient heat exchange. The steam drum 31 effectively separates the steam and the saturated hot water, ensuring that the steam can be exported or self-used in a stable state. The water supplement pipeline can supplement water in time according to the change of water amount in the system, to ensure the normal operation of the system.

[0066] The use of the above heat recovery system can significantly improve the energy utilization efficiency and reduce energy waste, not only reducing the cost of process operation, but also meeting the requirements of environmental protection and energy saving, providing strong support for the sustainable development of biomass synthesis gas shift process.

[0067] Example 4

[0068] Based on example 1, 2 or 3, this example discloses a catalyst gradient distribution biomass synthesis gas shift device, as shown in Figure 1 The device includes a gas-gas heat exchanger 21, a shift reactor 11 and a steam heat exchange assembly, as well as corresponding pipelines, instruments, valves and the like, wherein:

[0069] The CO shift reaction of the mixed steam and the biomass synthesis gas is performed in the multiple layers of catalyst beds arranged along the axial gradient in the shift reactor 11; the high-temperature shift gas output from the shift reactor 11 is heat-exchanged with the biomass synthesis gas in the gas-gas heat exchanger 21; and the heat generated in the CO shift reaction is heat-exchanged and recycled in the steam heat exchange assembly.

[0070] Further, the shift reactor 11 is sequentially provided with the first gas flow distributor 12, the first catalyst bed layer 13, the second gas flow distributor 14, the second catalyst bed layer 15, the third gas flow distributor 16 and the third catalyst bed layer 17 from the bottom to the top, which collectively complete the CO shift reaction.

[0071] With the above structure, the biomass synthesis gas enters the gas-gas heat exchanger 21 along the gas inlet pipeline, and is heat-exchanged with the high-temperature shift gas in the gas-gas heat exchanger 21. The heat of the high-temperature shift gas is partially transferred to the biomass synthesis gas, and the temperature of the biomass synthesis gas is raised, which is beneficial to the efficient performance of the subsequent shift reaction.

[0072] The biomass synthesis gas after being heated is divided into three parts along the pipeline. One part of the biomass synthesis gas is combined with the steam precisely controlled by the steam inlet flow control valve 02 and the steam inlet flow meter 03, and then enters the shift reactor 11 from the bottom of the shift reactor 11 after the flow is monitored by the synthesis gas inlet flow meter 01.

[0073] The steam inlet flow control valve 02 and the steam inlet flow meter 03 can dynamically and precisely control the flow ratio of the biomass synthesis gas and the steam entering the shift reactor 11, dynamically control the progress and reaction temperature of the shift reaction, and reduce the control operation difficulty of the hydrogen-carbon ratio of the shift gas.

[0074] The first catalyst bed layer 13, the second catalyst bed layer 15 and the third catalyst bed layer 17 of the shift reactor 11 all adopt the active enhanced sulfur-tolerant shift catalyst, and are arranged in gradient layers along the axial direction. Moreover, the first catalyst bed layer 13, the second catalyst bed layer 15 and the third catalyst bed layer 17 are all designed by referring to the tubular heat exchanger. The tube side is filled with the active enhanced sulfur-tolerant shift catalyst for the biomass synthesis gas shift reaction, and the shell side is filled with saturated hot water for removing the steam generated by the biomass synthesis gas shift reaction heat, which avoids the sintering of the catalyst bed caused by local overheating

[0075] One part of the biomass synthesis gas enters the shift gas outlet pipeline of the shift reactor 11 to adjust the high-temperature shift gas. The H2 / CO ratio monitor 07 is arranged at the outlet of the shift reactor 11 to monitor the hydrogen-carbon ratio of the shift gas in real time, and the H2 / CO ratio control valve 06 is arranged to adjust the hydrogen-carbon ratio of the shift gas in time, which further reduces the control operation difficulty of the hydrogen-carbon ratio of the shift gas and improves the practicability of the biomass synthesis gas shift process system.

[0076] A portion of the biomass syngas enters the shift reactor 11 through the first temperature gas flow control valve 04 and the second temperature gas flow control valve 05, which regulates the temperature and gas flow distribution of the outlet gas flow of the first catalyst bed 13 and the second catalyst bed 15.

[0077] Further, the steam heat exchange assembly includes a steam drum 31 and a hot water circulating pump 41, etc., wherein: the steam drum 31 performs gas-liquid separation on the recovered heat steam, and the steam is used as a product for external output or self-use, and the saturated hot water continues to circulate; the hot water circulating pump 41 transports the saturated hot water of the steam drum 31 into the catalyst bed through the hot water circulating pump 41 to exchange heat with the heat generated by the CO shift reaction to generate steam.

[0078] The steam heat exchange assembly further improves energy utilization efficiency and fully recycles the excess heat generated in the shift reaction. Through the heat exchange process with the catalyst bed, not only steam can be output or self-used, but also the temperature of the catalyst bed can be accurately controlled, creating more suitable temperature conditions for the CO shift reaction. This helps to improve the reaction rate and conversion rate, making the shift of biomass syngas more efficient.

[0079] At the same time, the stable operation of the steam heat exchange assembly can ensure the continuity and stability of the entire process system, reducing the adverse effects of temperature fluctuations and other factors on the reaction process. After the gas-liquid separation in the steam drum 31, the recycling of saturated hot water avoids the waste of energy and reduces production costs.

[0080] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and inventive concepts of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

[0081] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be directly above or obliquely above the first feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be directly below or obliquely below the first feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

Claims

1. A process for the shift conversion of a biomass syngas with a catalyst gradient distribution, characterized in that, The biomass synthesis gas and the high-temperature shift gas are exchanged heat through a gas-gas heat exchanger, mixed with steam, and then enter a shift reactor for CO shift reaction, and the output high-temperature shift gas is exchanged heat with the biomass synthesis gas through the gas-gas heat exchanger, and then is output as exchange gas. The catalyst beds are layered along the axial direction in the shift reactor, and the multiple catalyst beds are all made of activity-enhanced sulfur-tolerant shift catalysts and are layered along the axial direction.

2. The process according to claim 1, characterized in that, Each catalyst bed is made of a shell-and-tube heat exchanger, the tube side of which is filled with activity-enhanced sulfur-tolerant shift catalysts in a honeycomb shape, and the shell side of which is filled with saturated hot water.

3. The process of claim 2, wherein, Each catalyst bed is further provided with a corresponding gas flow distributor, the balanced gas flow holes of which are in a honeycomb shape, and the balanced gas flow holes are provided with balanced vanes.

4. The process according to claim 3, characterized in that, The steam pipeline is provided with a steam inlet flow meter and a steam inlet flow control valve along the gas flow direction, the biomass synthesis gas inlet pipeline is provided with a synthesis gas inlet flow meter before being connected to the steam pipeline, and the synthesis gas inlet flow meter is linked with the steam inlet flow control valve; 5. The process of claim 1, wherein, The biomass synthesis gas inlet pipeline is provided with an H2 / CO ratio control valve before being connected to the shift reactor outlet pipeline, and the shift reactor outlet pipeline is provided with an H2 / CO ratio monitor after being connected to the biomass synthesis gas inlet pipeline, and the H2 / CO ratio monitor is linked with the H2 / CO ratio control valve. The biomass synthesis gas inlet branch pipeline is connected between the catalyst beds and below the gas flow distributors.

6. The process of claim 1, wherein, Part of the heat generated by the CO shift reaction of the catalyst beds is recovered through a heat recovery system and then is utilized.

7. The process of claim 1, wherein, The heat recovery system comprises:

8. The process of claim 7, wherein, The saturated hot water in the steam drum is transported into the catalyst beds through a hot water circulating pump, exchanges heat with the heat generated by the CO shift reaction to generate steam, the steam returns to the steam drum for gas-liquid separation, the steam is output as a product or is used by itself, and the saturated hot water is continuously circulated through the hot water circulating pump. A biomass synthesis gas shift device with catalyst gradient distribution comprises:

9. Process according to any one of claims 1 to 7, characterized in that, a shift reactor which is provided with multiple catalyst beds layered along the axial direction and performs CO shift reaction on mixed steam biomass synthesis gas; a gas-gas heat exchanger which exchanges heat between the high-temperature shift gas output by the shift reactor and the biomass synthesis gas; a steam heat exchange assembly which exchanges and recovers the heat generated by the CO shift reaction. The steam heat exchange assembly comprises:

10. The process of claim 9, wherein, a steam drum which separates the recovered steam into gas and liquid, and the steam is output as a product or is used by itself, and the saturated hot water is continuously circulated; a hot water circulating pump which transports the saturated hot water in the steam drum into the catalyst beds through the hot water circulating pump, exchanges heat with the heat generated by the CO shift reaction to generate steam. ​

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