Two-channel fixed bed reactor, axial adiabatic coupling shift reactor and process thereof
By combining the segmented feeding design of the dual-channel fixed-bed reactor with water-cooled and gas-cooled heat exchange channels, the problems of poor temperature control and high equipment complexity in the shift reactor are solved. This enables flexible control of the shift gas temperature and improvement of steam quality, extends catalyst life, and reduces energy consumption.
Patent Information
- Application Number
- CN202411093693.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2026-02-10
AI Technical Summary
Existing shift reactors suffer from problems such as excessively long process flow, large pressure drop, poor temperature controllability, short catalyst life, low steam quality, and high equipment complexity. In particular, they are difficult to effectively regulate when the load changes and the catalyst activity decreases.
The reactor employs a dual-channel fixed-bed design with segmented feeding. It combines water-cooled and gas-cooled heat exchange channels and utilizes the different heat transfer coefficients of liquids and gases to achieve balanced control of the reaction temperature. Superheated steam is produced by adjusting the water-to-gas ratio and CO content through bypass gas intake.
It enables flexible adjustment of the shift gas temperature, reduces energy consumption, extends catalyst life, simplifies the process, improves steam quality, and reduces equipment investment.
Smart Images
Figure CN121490670A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of shift reaction equipment, specifically to a dual-channel fixed-bed reactor, an axially adiabatic coupled shift reactor, and their processes. Background Technology
[0002] A shift reaction is a reaction in which CO and water vapor react under certain conditions to produce CO2 and H2. It is a strongly exothermic reaction and a thermodynamically controlled process.
[0003] In existing processes, the conversion unit uses an adiabatic reactor or an isothermal reactor.
[0004] On the one hand, the limitation of adiabatic reactors is that, due to the large temperature rise caused by adiabatic heating, in order to avoid overheating of the reactor and to drive the reaction in the positive direction, the existing conversion processes are all multi-stage reactions and multiple cooling processes, but they all have the problems of excessively long process length and excessive pressure drop.
[0005] On the other hand, the limitations of isothermal reactors are:
[0006] (1) In the prior art, the temperature of the isothermal converter is determined by the catalyst loading and reaction equilibrium, and cannot be adjusted. In order to maintain a certain degree of superheat, the outlet gas of the isothermal converter is usually required to be stable above a certain temperature. However, when the crude syngas load changes or the catalyst activity decreases at the end, there is a lack of effective means to adjust the outlet temperature, so the controllability and adjustability are poor. Due to the influence of upstream load changes, water-gas ratio fluctuations, and catalyst temperature increases at the end, the outlet temperature of the converter needs to be adjusted frequently.
[0007] (2) The steam produced by the steam drum of the isothermal converter is saturated steam, which cannot produce higher quality superheated steam. The converter is a steam surplus unit, and the excess steam is usually supplied to other users in the plant through the steam network. However, saturated steam is prone to condensation due to its lower temperature, and cannot enter the network. Since most of the reaction heat of the isothermal converter is carried away by the water circulation system, the outlet temperature is only about 300°C, which cannot provide a superheat source. It can only be achieved by setting up a separate heating furnace or thermally combining it with other units, which increases the complexity of the process and the investment in equipment.
[0008] (3) In the prior art, the isothermal reactor is a single-channel tubular reactor, and the feed gas flows from top to bottom along the axial direction. The CO content in the feed gas is high, while the CO content in the outlet shift gas is low. Therefore, the reaction at the upper end of the reactor is more intense and releases more heat, while the reaction at the lower end of the reactor is milder and releases less heat. The hot spot temperature of the reactor is concentrated at the upper end of the reactor, which makes the upper end of the reactor prone to overheating and has a shorter catalyst life and faster deactivation.
[0009] In addition, existing adiabatic reactors and isothermal shift reactors all require the crude syngas to be heated above the catalyst activation temperature before it can enter the shift furnace. Summary of the Invention
[0010] The technical problem to be solved by the present invention is to provide a semi-isothermal converter with segmented feeding and controllable and adjustable converter gas temperature to meet the requirements of crude syngas conversion reaction under different loads and water-to-gas ratios. At the same time, it can be combined with the entire conversion heat exchange network process to flexibly adjust the outlet converter gas temperature to meet the requirements of the by-product steam grade and superheat of the conversion unit.
[0011] On one hand, the present invention provides a fixed-bed reactor having a shell and a hollow reaction chamber. A partition is provided inside the shell, dividing the hollow reaction chamber into an upper chamber and a lower chamber. The upper chamber has an air inlet; the lower chamber has an air outlet. A cylindrical body is fitted inside the upper chamber, serving as a first reaction chamber. A heat exchange unit is provided inside the cylindrical body. The heat exchange unit includes a water-cooled heat exchange assembly and an air-cooled heat exchange assembly. The water-cooled heat exchange assembly consists of several water-cooled heat exchange plates; the air-cooled heat exchange assembly consists of several air-cooled heat exchange plates. A radially extending upper plate and lower plate are provided inside the lower chamber, forming a second reaction chamber with the upper plate, the inner wall of the shell, and the lower plate. The upper plate has several vent holes II, and the lower plate has several vent holes III. Both ends of the upper plate and both ends of the lower plate are sealed to the inner wall of the shell.
[0012] As a preferred technical solution, the air-cooled heat exchange component has a preheated gas inlet and a preheated gas outlet, and the preheated gas outlet is connected to the air inlet.
[0013] As a preferred technical solution, a gap is left between the side wall of the cylinder and the inner wall of the shell to serve as an air intake channel; the side wall of the cylinder is provided with several vent holes I; at the center of the cylinder, there is an axially extending central pipe, the pipe wall of the central pipe is provided with several air collection holes, the upper end of the central pipe is closed, and the lower end of the central pipe is connected to the lower chamber.
[0014] In one implementation, the preheated gas outlet is connected to the air inlet channel, meaning that the preheated gas is not discharged outside the reactor, but directly enters the air inlet channel.
[0015] As a preferred technical solution, the air inlet includes a first air inlet and a second air inlet; the first air inlet is located at the top of the upper chamber, the second air inlet is located in the middle of the upper chamber, and the second air inlet is connected to the central tube.
[0016] As a preferred technical solution, the air outlet is located at the bottom of the lower chamber.
[0017] As a preferred technical solution, a gas distributor is provided between the lower end of the central tube and the lower chamber.
[0018] As a preferred technical solution, the heat exchange unit extends radially within the first reaction chamber.
[0019] As a preferred technical solution, the single water-cooled heat exchange plate and the single air-cooled heat exchange plate are integrated into one unit as a single integrated heat exchange plate; preferably, several integrated heat exchange plates are arranged radially around the central tube; preferably, the air-cooled heat exchange plates are close to the central tube, and the water-cooled heat exchange plates are far away from the central tube.
[0020] As a preferred technical solution, the first reaction chamber is filled with a heat-exchange reaction catalyst between the sidewall and the central tube; the second reaction chamber is filled with an adiabatic reaction catalyst.
[0021] On the other hand, the present invention provides a shift reactor, which uses any of the above-described fixed-bed reactors as the shift reactor.
[0022] On another aspect, the present invention provides a process for reacting gas to enter any of the above-mentioned fixed-bed reactors for reaction, wherein the reacting gas consists of a first inlet gas and a second inlet gas; preferably, the inlet gas volume of the first inlet gas: the inlet gas volume of the second inlet gas = 10-80: 30-100, more preferably, the inlet gas volume of the first inlet gas: the inlet gas volume of the second inlet gas = 30-50: 40-80, more preferably, the first inlet gas accounts for 40% of the raw material gas: the second inlet gas accounts for 60% of the raw material gas. The first inlet gas enters through the first inlet gas port, flows sequentially through the inlet gas channel and vent I into the first reaction chamber, and after the reaction, flows sequentially through the gas collecting port I, the central tube, the distributor, and the vent II into the second reaction chamber; the first inlet gas enters through the second inlet gas port, flows sequentially through the central tube, the distributor, and the vent II into the second reaction chamber; the gas in the second reaction chamber, after the reaction, is discharged through the vent III and the outlet gas port.
[0023] As a preferred technical solution, the reaction gas is preferably a synthesis gas; the gas discharged from the outlet is a shift gas.
[0024] As a preferred technical solution, the dry volume content of carbon monoxide in the synthesis gas is 30% to 90%.
[0025] As a preferred technical solution, the water / dry gas volume ratio in the synthesis gas is 0.1 to 1.6.
[0026] As a preferred technical solution, the temperature of the gas discharged from the outlet is ≥400℃.
[0027] The beneficial effects of this invention are:
[0028] (1) The reactor provided by the present invention has a wide range of applications and can be used for raw materials with a carbon monoxide dry volume content of 30% to 90% and a water / dry gas volume ratio of 0.1 to 1.6.
[0029] (2) The isothermal reactor of the present invention adopts an axial-radial structure, which shortens the length of the synthesis gas flow channel and reduces the pressure drop of the reactor, thereby saving the downstream compression power consumption and reducing the energy consumption of the entire device. It is an energy-saving device.
[0030] (3) This invention removes the heat of reaction in a timely manner by setting up dual heat exchange channels of air cooling and water cooling in the isothermal reaction zone, thereby effectively controlling the temperature of the shift gas in the isothermal zone and causing the reaction to proceed in the positive direction. Saturated steam is obtained at the outlet of the water cooling channel, and preheated crude synthesis gas above the catalyst activation temperature is obtained at the outlet of the air cooling channel, thus maximizing the utilization of energy.
[0031] (4) This invention employs an axial-radial dual-channel reactor. Since the reactor uses both water-cooled and gas-cooled channels, it utilizes the different heat transfer coefficients of liquids and gases. The outer side, where the reaction is more vigorous, uses a liquid with a higher heat transfer coefficient for heat exchange, while the inner side, where the reaction is milder, uses a gas with a lower heat transfer coefficient for heat exchange. This better ensures the temperature uniformity of the entire catalyst bed, reduces temperature gradients in different parts of the catalyst bed, and effectively avoids overheating and catalyst deactivation. Furthermore, the radial flow channel utilizes the different heat exchange areas on the inner and outer sides. The outer side has a larger heat exchange area, corresponding to the part of the reaction with intense exothermic activity, and thus extracts more heat. The inner side has a smaller heat exchange area, corresponding to the part of the reaction with exothermic activity, and thus extracts less heat.
[0032] (5) The present invention provides a crude syngas bypass inlet. The crude syngas injected from the bypass mixes with the crude conversion gas obtained from the outlet of the upper isothermal zone gas-cooled channel. Since the crude syngas obtained from the outlet of the gas-cooled channel has been preheated to above the catalyst activation temperature, the crude syngas entering from the bypass does not need to be separately heated to the activation temperature and can reach the activation temperature directly, thus eliminating the equipment investment of the crude syngas preheater, reducing the complexity of the process, and avoiding the tube sheet leakage problem caused by the excessive temperature difference on the shell and tube sides of the crude syngas preheater.
[0033] (6) This invention employs segmented reaction technology, setting up an axial adiabatic reaction zone in the lower section of the furnace body. By adjusting the bypass crude syngas intake, the water-to-gas ratio, CO content, and outlet temperature of the mixed shift gas entering the adiabatic reaction zone can be flexibly and effectively adjusted and controlled. By effectively adjusting the outlet temperature of the shift gas to above 400℃, superheated steam can be produced, saving equipment investment and operating costs, ensuring the stability of the downstream heat exchange network, not only having no impact on the steam production pressure, but also solving the problems of easy overheating and difficult temperature control in the shift reaction of high CO content feed gas. Attached Figure Description
[0034] Figure 1 A schematic diagram of one embodiment of a fixed-bed reactor;
[0035] Figure 2A cross-sectional schematic diagram of one embodiment of a fixed-bed reactor;
[0036] Figure 3 Partial schematic diagram of the heat exchange unit;
[0037] Figure 4 A cross-sectional schematic diagram of another embodiment of a fixed-bed reactor;
[0038] 1. Shell; 11. First air inlet; 12. Second air inlet; 13. Air outlet; 14. Upper chamber; 141. Vent hole I; 15. Central tube; 151. Gas collecting hole; 50. Lower chamber; 501. Vent hole II; 502. Vent hole III; 51. Catalyst; 52. Ceramic ball; 43. Gas distributor; 41. Heat exchange unit; 200. Air-cooled heat exchange plate; 210. Water-cooled heat exchange plate; 20. Air-cooled air inlet; 201. Air-cooled air inlet pipe; 202. Air-cooled distribution ring pipe; 203. Air-cooled riser pipe; 204. Preheated gas riser pipe; 205. Preheated gas collecting ring pipe; 206. Preheated gas riser main pipe; 18. Preheated gas outlet; 21. Water-cooled water inlet; 211. Water-cooled inlet main pipe; 212. Water-cooled distribution ring; 213. Water-cooled riser pipe; 214. Steam riser pipe; 215. Steam collecting ring pipe; 216. Steam riser main pipe; 22. Steam outlet; 28. Expansion joint. Detailed Implementation
[0039] The following are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any technical solutions that fall within the scope of the present invention should be included in the scope of protection of the present invention. For those skilled in the art, any minor improvements made to the present invention without departing from the principle of the present invention should also be included in the scope of protection of the present invention.
[0040] Unless otherwise specified, all components and fittings used in the preparation examples, embodiments and comparative examples of this invention are commercially available products.
[0041] Example 1 Fixed Bed Reactor
[0042] like Figure 1 As shown, the fixed-bed reactor has a shell (with an insulation layer on the outer periphery) and a hollow reaction chamber. A partition is provided inside the shell 1, dividing the hollow reaction chamber into an upper chamber and a lower chamber. The upper chamber has an air inlet; the lower chamber has an air outlet 13. A cylindrical body is fitted inside the upper chamber, serving as the first reaction chamber. A heat exchange unit is provided inside the cylindrical body to remove the reaction heat from the first reaction chamber in a timely manner. The heat exchange unit includes a water-cooled heat exchange component and an air-cooled heat exchange component. The water-cooled heat exchange component consists of several water-cooled heat exchange plates; the air-cooled heat exchange component consists of several air-cooled heat exchange plates. Inside the lower chamber, from top to bottom, there are radially extending upper and lower plates, the edges of which are sealed and fixedly connected to the shell. The upper plate, the inner wall of the shell, and the lower plate constitute the second reaction chamber. The upper plate has several vent holes II, and the lower plate has several vent holes III.
[0043] Example 2 Fixed Bed Reactor
[0044] like Figure 1 , Figure 2 As shown, the fixed-bed reactor has a shell (with an outer insulation layer) and a hollow reaction chamber. A partition inside the shell 1 divides the hollow reaction chamber into an upper chamber 14 (for isothermal reactions) and a lower chamber 50 (for adiabatic reactions). The upper chamber 14 has a first air inlet 11 at the top and a second air inlet 12 in the middle. The lower chamber 50 has an air outlet 13. A cylindrical body (catalyst cylinder) is fitted inside the upper chamber 14, serving as the first reaction chamber. The sidewall of the cylindrical body has several vent holes I 141, with a gap (outer air inlet annular gap) between the sidewall and the inner wall of the shell. The first air inlet 11, the gap, and the vent holes I 141 are sequentially connected to form an annular air inlet channel. At the center of the cylindrical body, an axially extending central pipe 15 is provided. The wall of the central pipe 15 has several gas collecting holes 151 (inner air inlet annular gap). The upper end of the central pipe is closed, and the lower end connects to the lower chamber 50. The cylinder is equipped with a heat exchange unit 41 for timely removal of reaction heat from the first reaction chamber. The heat exchange unit includes a water-cooled heat exchange component and an air-cooled heat exchange component. The water-cooled heat exchange component is composed of several water-cooled heat exchange plates. The air-cooled heat exchange component is composed of several air-cooled heat exchange plates. In the lower chamber 50, an upper plate and a lower plate extending radially are respectively provided from top to bottom in the axial direction. The edges of the upper plate and the lower plate are sealed and fixedly connected to the shell. The upper plate and the lower plate form a second reaction chamber. The upper plate is provided with several vent holes II 501, and the lower plate is provided with several vent holes III 502.
[0045] Example 3 Fixed Bed Reactor
[0046] like Figure 1 , Figure 3As shown, the fixed-bed reactor has a shell (with an insulation layer on the outer periphery) and a hollow reaction chamber. The shell 1 is equipped with a partition, which divides the hollow reaction chamber into an upper chamber 14 (where isothermal reaction occurs) and a lower chamber 50 (where adiabatic reaction occurs). The upper chamber has an air inlet, and the lower chamber has an air outlet. A cylinder is fitted inside the upper chamber, and the cylinder serves as the first reaction chamber. A heat exchange unit 41 is provided inside the cylinder to remove the reaction heat in the first reaction chamber in a timely manner. The heat exchange unit 41 includes a water-cooled heat exchange component and an air-cooled heat exchange component. The air-cooled heat exchange component has an air-cooled inlet and a preheated gas outlet, and the preheated gas outlet is connected to the air inlet. The water-cooled heat exchange assembly consists of several water-cooled heat exchange plates; the air-cooled heat exchange assembly consists of several air-cooled heat exchange plates; and the single water-cooled heat exchange plate 210 and the single air-cooled heat exchange plate 200 are integrated into one unit as a single dual-channel integrated heat exchange plate; the several dual-channel integrated heat exchange plates are arranged radially from the center, with the air-cooled heat exchange plate 200 close to the axis center and the water-cooled heat exchange plate 210 far from the axis center. Boiler water flows through the water-cooled heat exchange plate 210 as the heat exchange medium, and the raw material gas to be preheated flows through the air-cooled heat exchange plate 200 as the heat exchange medium.
[0047] Example 4 Shift Reactor
[0048] like Figure 1 , Figure 2 , Figure 3As shown, the shift reactor has a shell (with an outer insulation layer) and a hollow reaction chamber. A partition inside the shell divides the hollow reaction chamber into an upper chamber 14 (for isothermal shift reaction) and a lower chamber 50 (for adiabatic shift reaction). The upper chamber 14 has a first inlet 11 (main inlet for crude syngas) at the top and a second inlet 12 (side inlet for crude syngas) in the middle. The lower chamber 50 has an outlet 13. A cylinder is fitted inside the upper chamber 14, serving as the first reaction chamber. To ensure more uniform distribution of the raw gas, a gas distributor can be installed at the first inlet 11. The sidewall of the cylinder has several vent holes I 141, with an annular gap between the sidewall and the inner wall of the shell, serving as an annular inlet channel. The first inlet 11, the gap, and the vent holes I 141 are sequentially connected. A centrally extending pipe 15 is located at the center of the cylinder, used to collect the shift gas and send it to the second reaction chamber. The central tube 15 has several gas collecting holes 151 on its wall. The upper end of the central tube is closed, and the lower end is connected to the lower chamber 50. The second air inlet is connected to the lower end of the central tube 15. Inside the lower chamber 50, from top to bottom, there are an upper plate and a lower plate extending radially. The edges of the upper plate and the lower plate are sealed and fixed to the shell, forming a second reaction chamber. The upper plate has several vent holes II 501, and the lower plate has several vent holes III 502. The gas flows from the first air inlet 11, then into the annular space between the upper chamber 14 and the shell, through the vent holes I 141, into the central tube 15, then through the gas distributor 43 into the lower chamber 50, through the vent holes II 501, the catalyst 51, the ceramic balls 52, and finally out from the outlet 13. The cylinder is equipped with a heat exchange unit 41 for timely removal of reaction heat from the first reaction chamber. The heat exchange unit includes a water-cooled heat exchange component and an air-cooled heat exchange component. The water-cooled heat exchange component is composed of several water-cooled heat exchange plates. The air-cooled heat exchange component is composed of several air-cooled heat exchange plates. The water-cooled heat exchange component is composed of several water-cooled heat exchange plates. The air-cooled heat exchange component is composed of several air-cooled heat exchange plates. The individual water-cooled heat exchange plate 210 and the individual air-cooled heat exchange plate 200 are integrated into one unit as a single dual-channel integrated heat exchange plate. The several dual-channel integrated heat exchange plates are arranged radially from the center, with the air-cooled heat exchange plate 200 close to the axis center and the water-cooled heat exchange plate 210 far from the axis center. Boiler water flows through the water-cooled heat exchange plate 210 as the heat exchange medium, and the crude syngas to be preheated flows through the air-cooled heat exchange plate 200 as the heat exchange medium. The heat exchange unit 41 is provided with an air-cooled inlet 20, a preheated gas outlet 18 (gas is discharged after preheating), a water-cooled inlet 21, and a steam outlet 22 (water is discharged in the form of steam). The preheated gas outlet is connected to the inlet.
[0049] Example 5: Shifting Reaction Process
[0050] The crude syngas enters the shift reactor of Example 4 for a shift reaction.
[0051] The space between the sidewalls of the cylinder and the central tube is filled with a catalyst (isothermal shift reaction catalyst).
[0052] The second reaction chamber is filled with catalyst 51 (adiabatic shift reaction catalyst) and ceramic balls 52.
[0053] The boiler water inlet 21, water-cooled inlet main pipe 211, water-cooled distribution ring 212, several water-cooled riser pipes 213, water-cooled heat exchange plates 210, several steam riser pipes 214, steam outlet 22 (discharged in steam form), steam collection ring pipe 215, and steam riser main pipe 216 are connected in sequence. The several water-cooled riser pipes 213 are evenly distributed in the water-cooled distribution ring 212, and each water-cooled riser pipe 213 is connected to one water-cooled heat exchange plate 210. The several steam riser pipes 214 are evenly distributed in the steam collection ring pipe 215, and the steam collection ring pipe 215 sends saturated steam out of the boundary via the steam riser main pipe 216.
[0054] The system comprises an air-cooled inlet 20 (preheating inlet for crude syngas), an air-cooled inlet pipe 201, an air-cooled distribution ring pipe 202, several air-cooled riser pipes 203, an air-cooled heat exchange plate 200, several preheated gas riser pipes 204, a preheated gas outlet 18, a preheated gas collection ring pipe 205, and a preheated gas riser main pipe 206, which are connected in sequence. The several air-cooled riser pipes 203 are evenly distributed within the air-cooled distribution ring 202, and each air-cooled riser pipe 203 is connected to one air-cooled heat exchange plate 200. The several preheated gas riser pipes 204 are evenly distributed within the gas medium collection ring pipe 205, which delivers the preheated crude syngas to the outside via the gas medium riser main pipe 206.
[0055] The preheated crude syngas enters the gas-cooled inlet 20, flows through the gas-cooled inlet pipe 201, the cold distribution ring pipe 202, several gas-cooled riser pipes 203, the gas-cooled heat exchange plate 200, the preheated gas riser pipe 204, the preheated gas outlet 18, the preheated gas collection ring pipe 205, and the preheated gas riser main pipe 206, and is discharged through the preheated gas outlet 18 before entering the inlet (preferably 40% enters the first inlet and 60% enters the second inlet). While producing saturated steam as a byproduct, the crude syngas can also be preheated to above the catalyst activation temperature, reducing the investment cost of the preheater.
[0056] like Figure 2 As shown, the preheated gas outlet 18 is located outside the reactor. After passing through the heat exchange plate, the preheated gas exits the reactor from the preheated gas outlet 18 at the top of the reactor and then enters the first air inlet 11. This air intake method allows for flexible adjustment of the crude syngas and preheated syngas volumes. Each steam riser pipe 214 and each preheated gas riser pipe 204 is equipped with an expansion joint 28 in the middle, effectively solving the problem of thermal expansion caused by temperature differences in the upper section of the reactor.
[0057] like Figure 4 As shown, the preheated gas outlet 18 is located inside the reactor. Alternatively, the preheated gas can be discharged from the reactor without passing through the preheated gas outlet 18. The preheated gas outlet 18 is located inside the reactor and directly connects to gap I, meaning the preheated gas directly enters gap I through the preheated gas outlet 18. This intake method eliminates the need to route the preheated crude syngas outside the reactor, resulting in minimal heat loss, but poor gas flow regulation. Each steam riser pipe 214 is equipped with an expansion joint 28 in the middle, effectively solving the thermal expansion problem caused by temperature differences in the upper section of the reactor.
[0058] The upper inspection port 34 is used for loading and unloading the catalyst in the upper isothermal section and for inspecting and maintaining the heat exchange module; the middle inspection port 35 is used for loading the catalyst in the lower adiabatic section and for inspecting and maintaining the adiabatic section; the lower inspection port 36 is used for unloading the catalyst in the lower adiabatic section; and the pressure grid 42 is used to fix the catalyst bed.
[0059] The feed gas (crude syngas, with a carbon monoxide dry basis volume content of 30%–90% and a water / oxygen dry gas volume ratio of 0.1–1.6) consists of a first inlet (40% of the total inlet gas) and a second inlet (60% of the total inlet gas). The first inlet gas enters the shell 1 through the first inlet port, and the second inlet gas enters the shell 1 through the second inlet port 12, serving as a bypass. By adjusting the bypass syngas inlet flow rate, the water-to-gas ratio and CO content of the mixed shift gas entering the adiabatic reaction zone can be controlled, thereby effectively regulating the shift gas outlet temperature. The axial adiabatic reaction zone has a similar structure to the heat exchange reaction zone, but it lacks heat exchange channels; therefore, the outlet temperature of the shift gas after the reaction can reach over 400℃.
[0060] The first intake air enters the first reaction chamber 14 through the first intake port 11, the annular intake channel, and the vent I 141. The heat generated by the catalyst bed during the reaction is carried away by the heat exchange unit 41 in time. The reaction gas is collected in the central tube 15 through each gas collecting hole I 151 and mixed with the first intake air from the second intake port 12 to obtain mixed gas.
[0061] The mixed shift gas from the heat exchange reaction zone is dispersed by the gas distributor 43 and enters the second chamber axially through the vent II 501. After the reaction, it is discharged from the shell 1 through the vent III 502 and the outlet 13. If the catalyst activity decreases in the later stage of the reaction, or the shift gas outlet temperature is too low, the shift gas outlet temperature can be increased by adjusting the syngas side inlet gas flow rate to 75% to ensure the temperature of the downstream heat exchange system.
Claims
1. A fixed-bed reactor, comprising a shell and a hollow reaction chamber, characterized in that, The shell is equipped with a partition, which divides the hollow reaction chamber into an upper chamber and a lower chamber; The upper chamber is equipped with an air inlet; The lower chamber is equipped with an air vent; A cylindrical body is installed inside the upper chamber, and the inside of the cylindrical body serves as the first reaction chamber. The cylinder is equipped with a heat exchange unit; the heat exchange unit includes a water-cooled heat exchange component and an air-cooled heat exchange component. The water-cooled heat exchange assembly consists of several water-cooled heat exchange plates; The air-cooled heat exchange assembly consists of several air-cooled heat exchange plates; The lower chamber is provided with a radially extending upper plate and a lower plate, and the upper plate, the inner wall of the shell and the lower plate form a second reaction chamber; the upper plate is provided with several vent holes II and the lower plate is provided with several vent holes III.
2. The fixed-bed reactor according to claim 1, characterized in that, The air-cooled heat exchanger has a preheated gas inlet and a preheated gas outlet, and the preheated gas outlet is connected to the air inlet. And / or, a gap is left between the side wall of the cylinder and the inner wall of the shell to serve as an air intake channel; the side wall of the cylinder is provided with several vent holes I; at the center of the cylinder, there is an axially extending central tube, the tube wall of which is provided with several air collection holes, the upper end of the central tube is closed, and the lower end of the central tube is connected to the lower chamber. And / or, the preheated gas outlet is connected to the air inlet channel.
3. The fixed-bed reactor according to claim 1 or 2, characterized in that, The air inlet includes a first air inlet and a second air inlet; The first air inlet is located at the top of the upper chamber, and the second air inlet is located in the middle of the upper chamber. The second air inlet is connected to the central tube. And / or, the air outlet is located at the bottom of the lower chamber.
4. The fixed-bed reactor according to claim 1, 2, or 3, characterized in that, A gas distributor is provided between the lower end of the central tube and the lower chamber.
5. The fixed-bed reactor according to any one of claims 1-4, characterized in that, The heat exchange unit extends radially within the first reaction chamber; And / or, the single water-cooled heat exchange plate and the single air-cooled heat exchange plate are integrated into one unit as a single integrated heat exchange plate; preferably, several integrated heat exchange plates are arranged radially around the central tube; preferably, the air-cooled heat exchange plates are close to the central tube, and the water-cooled heat exchange plates are far away from the central tube.
6. The fixed-bed reactor according to claim 1, characterized in that, The space between the sidewall and the central tube in the first reaction chamber is filled with a heat-exchange reaction catalyst. The second reaction chamber is filled with an adiabatic reaction catalyst.
7. A shift reactor, characterized in that, The fixed-bed reactor according to any one of claims 1-6 is used as the shift reactor.
8. A process in which the reactant gas enters a fixed-bed reactor according to any one of claims 1-6 for reaction, characterized in that, The reaction gas consists of a first inlet and a second inlet; Preferably, the air intake volume of the first air intake : the air intake volume of the second air intake = 10~80 : 30~100; Preferably, the air intake volume of the first air intake : the air intake volume of the second air intake = 30~50 : 40~80; Even better, the first intake accounts for 40% of the raw material gas; the second intake accounts for 60% of the raw material gas. The first air intake enters through the first air intake port, flows sequentially through the air intake channel and vent I into the first reaction chamber, and after the reaction, flows sequentially through the air collection port I, the central tube, the distributor, and the vent II into the second reaction chamber. The first air intake enters through the second air intake, and flows sequentially through the central tube, the distributor, and the vent II into the second reaction chamber; After the gas in the second reaction chamber reacts, it is discharged through vent III and the outlet.
9. The process according to claim 8, characterized in that, The reaction gas is preferably a synthesis gas; The gas discharged from the outlet is a shift gas; Preferably, the syngas contains 30% to 90% carbon monoxide by dry volume. And / or, in the synthesis gas, the water / dry gas volume ratio is 0.1 to 1.
6.
10. The process according to claim 8 or 9, characterized in that, The temperature of the gas discharged from the outlet is ≥400℃.