Finned tube heat exchange type methanol catalytic synthesis reactor

Abstract

This invention provides a finned tube heat exchange type methanol catalytic synthesis reactor, comprising a cylindrical body with tube sheets installed at its upper and lower ends. Elliptical end caps are provided on the sides of the two tube sheets that are far apart from each other, and the tube sheets and elliptical end caps are fixedly connected by equipment flanges. This design features a simplified structure and low manufacturing cost. By employing a finned tube distributed heat exchange device and filling the catalyst within the tube-side reaction zone of the finned tubes, the structure is simplified, reducing processing difficulty and manufacturing costs. This design achieves indirect heat exchange through the finned tube wall. The reaction heat is circulated to the outside of the tube by heat transfer oil, cooled to liquid by cooling water, and then uniformly heated by an electric heater before returning to the shell side, forming a closed-loop circulation for precise temperature control. This achieves stable temperature control of the reaction bed, avoiding the sawtooth temperature fluctuations of a quench reactor, which is beneficial for protecting the catalyst and improving reaction efficiency.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis equipment technology, specifically a finned tube heat exchange type methanol catalytic synthesis reactor. Background Technology

[0002] Methanol is synthesized by the catalytic reaction of carbon monoxide and hydrogen in a strongly exothermic and reversible process. The control of the reaction temperature directly affects the catalyst lifetime and yield. There are two main types of existing methanol synthesis reactors: one is the shell-and-tube water-cooled reactor, which provides stable temperature control but has a complex structure and high cost, and is mainly suitable for ultra-large-scale plants; the other is the adiabatic fixed-bed reactor, which has a relatively simple structure but poor temperature control, resulting in problems such as sawtooth fluctuations or low conversion rates.

[0003] Finned tube heat exchangers are widely used due to their high heat transfer efficiency and compact structure. For example, prior art document 1 (CN108519007A) discloses a self-supporting double-helix finned tube heat exchanger, which enhances heat transfer through finned tubes, simplifies the structure, and reduces costs. However, prior art document 1 is essentially a pure heat exchange device, with the tubes serving only as fluid channels. It cannot be filled with catalysts, lacks an active and precise control mechanism for the reaction temperature, and does not consider the uniform distribution of reactant gases, making it difficult to directly use for methanol catalytic synthesis.

[0004] Therefore, there is a need in the field for a methanol synthesis reactor that combines stable temperature control, relatively simple structure, low pressure drop, and suitability for small and medium-scale production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, a finned tube heat exchange methanol catalytic synthesis reactor with a relatively simple structure, low pressure reduction, and the ability to achieve precise and stable temperature control of the reaction bed under a wide range of operational flexibility is provided. This reactor is particularly suitable for small and medium-scale methanol production.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a finned tube heat exchange type methanol catalytic synthesis reactor, comprising a cylindrical body, wherein tube sheets are respectively provided at the upper and lower ends of the cylindrical body, and two elliptical heads are respectively connected to the outside of the tube sheets at the upper and lower ends of the cylindrical body through equipment flanges.

[0007] Preferably, the upper and lower ends of the multiple finned tubes are respectively fixed to the upper and lower tube sheets. The internal space of the finned tubes constitutes a tube-side reaction zone for filling the methanol synthesis catalyst. The outer side of the finned tubes, the inner wall of the cylinder, and the upper and lower tube sheets together form a sealed shell-side cavity, which is used to contain heat transfer oil.

[0008] Preferably, the lower elliptical end cap is provided with a syngas inlet, and the upper elliptical end cap is provided with a syngas outlet. The cylinder body is provided with a heat transfer oil inlet and a heat transfer oil outlet communicating with the shell-side cavity.

[0009] Preferably, the reactor further includes an external circulation temperature control system for heat transfer oil, the system comprising: a circulation pipeline connecting the heat transfer oil outlet and the heat transfer oil inlet; a cooler disposed on the circulation pipeline for cooling the heat transfer oil flowing out from the heat transfer oil outlet; an electric heater disposed on the circulation pipeline and downstream of the cooler for precisely reheating the cooled heat transfer oil; and a circulation pump for driving the heat transfer oil to circulate between the shell-side cavity and the external circulation temperature control system for heat transfer oil.

[0010] Preferably, the lower elliptical head is provided with a gas distribution structure, which includes a distribution pipe located above the synthesis gas inlet and a horizontally mounted perforated plate. The distribution pipe and the perforated plate cooperate to distribute the raw material gas evenly to the tube side reaction zone of each finned tube.

[0011] Preferably, a pressure plate is provided on the inner side of the tube sheet, and the pressure plate is fixed to the tube sheet by bolts; a wire mesh is provided between the pressure plate and the end of the finned tube, and the wire mesh is used to press and cover the end of the finned tube to prevent catalyst particles from entering the elliptical head.

[0012] Preferably, the finned tube is an integral finned tube, wherein the fins and the base tube are integrally formed.

[0013] Preferably, the upper elliptical head is provided with a tube-side pressure gauge port and a tube-side thermometer port; the cylinder is provided with a shell-side detection port communicating with the shell-side cavity, a liquid level gauge port extending into the shell-side cavity, and a vent port and an oil drain port communicating with the shell-side cavity; the outer wall surface of the cylinder is provided with a plurality of lug supports, which are arranged in a ring array; the cylinder is also provided with a manual valve port.

[0014] This invention provides a finned tube heat exchange type methanol catalytic synthesis reactor. It has the following beneficial effects: 1. This solution has a simplified structure and low manufacturing cost. By adopting a finned tube distributed heat exchange device and filling the catalyst in the tube-side reaction zone of the finned tube, the structure is simplified, reducing the processing difficulty and manufacturing cost.

[0015] 2. This scheme uses indirect heat exchange through the finned tube wall. The heat of reaction is circulated to the outside of the tube by the heat transfer oil, cooled into liquid by cooling water, and then uniformly heated by an electric heater before returning to the shell side, forming a closed-loop circulation for precise temperature control. This achieves stable control of the reaction bed temperature, avoids the sawtooth temperature fluctuations of the cold-quench reactor, and is beneficial for protecting the catalyst and improving reaction efficiency.

[0016] 3. Compared with other finned tubes, the integral finned tubes used in this solution are rolled, machined or cast to make the base tube and fins into a whole, which has higher heat transfer efficiency, zero contact thermal resistance, good strength and long service life.

[0017] 4. This scheme combines the advantages of good temperature control of shell-and-tube reactors with the relatively simple structure of adiabatic reactors. At the same time, the system pressure drop is reduced by loading catalyst in the tube side, making it particularly suitable for small and medium-sized methanol production plants and with broad application prospects.

[0018] 5. This scheme only requires one catalyst loading and heating reduction operation, which is simple and avoids the risks of errors and mismatched reduction conditions that may occur with multi-stage loading. It improves the reliability and efficiency of start-up. The catalyst in the entire reactor has a uniform life cycle and can be replaced in a planned manner. This avoids unplanned shutdowns or frequent maintenance caused by partial catalyst deactivation or segmented replacement, which is conducive to the long-term stable operation of the production unit. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the external structure of the present invention; Figure 2 This is a top view of the external structure of the present invention; Figure 3 This is a front view of the external structure of the present invention; Figure 4 For the present invention Figure 3 A cross-sectional view along the AA direction.

[0020] In the diagram: 101, distribution pipe; 102, elliptical head; 103, orifice plate; 104, bolt; 105, pressure plate; 106, wire mesh; 107, tube sheet; 108, equipment flange; 109, shell; 110, finned tube; 112, lug support; 113, heat transfer oil inlet; 114, heat transfer oil outlet; 115, syngas inlet; 116, syngas outlet; 117, manual valve port; 118, level gauge port; 119, tube-side pressure gauge port; 120, tube-side thermometer port; 121, shell-side detection port; 123, vent port; 124, oil drain port; 125, tube-side reaction zone; 126, shell-side cavity; 1001, finned tube heat exchanger piping. Detailed Implementation

[0021] This invention provides a finned tube heat exchange type methanol catalytic synthesis reactor, such as... Figures 1 to 4 As shown, the device includes a cylindrical body 109, with tube sheets 107 installed at the upper and lower ends of the cylindrical body 109 respectively. Elliptical end caps 102 are provided on the sides of the two tube sheets 107 that are far apart from each other. The tube sheets 107 and the elliptical end caps 102 are fixedly connected by a device flange 108.

[0022] Furthermore, the upper and lower ends of the multiple finned tubes 110 are respectively fixed to the upper and lower tube sheets 107. The internal space of the finned tubes 110 constitutes the tube-side reaction zone 125 for filling the methanol synthesis catalyst. The outer side of the finned tubes 110, the inner wall of the cylinder 109, and the upper and lower tube sheets 107 together form a closed shell-side cavity 126, which is used to contain heat transfer oil. The multiple finned tubes 110 together constitute the finned tube heat exchange pipeline 1001.

[0023] Furthermore, the lower elliptical head 102 is provided with a syngas inlet 115, the upper elliptical head 102 is provided with a syngas outlet 116, and the cylinder 109 is provided with a heat transfer oil inlet 113 and a heat transfer oil outlet 114 that communicate with the shell-side cavity 126.

[0024] Furthermore, this embodiment also includes an external circulation temperature control system for heat transfer oil, which includes a circulation pipeline connecting the heat transfer oil outlet 114 and the heat transfer oil inlet 113; A cooler, installed on the circulation pipeline, is used to cool the heat transfer oil flowing out from the heat transfer oil outlet 114; An electric heater, installed on the circulation pipeline and located downstream of the cooler, is used to precisely reheat the cooled heat transfer oil; And a circulation pump for driving the heat transfer oil to circulate between the shell cavity 126 and the external circulation temperature control system for the heat transfer oil.

[0025] Furthermore, the lower elliptical head 102 is provided with a gas distribution structure, which includes a distribution pipe 101 located above the synthesis gas inlet 115 and a horizontally mounted perforated plate 103. The distribution pipe 101 and the perforated plate 103 cooperate to uniformly distribute the raw material gas to the tube side reaction zone 125 of each finned tube 110 to prevent flow deviation and improve the utilization efficiency of the catalyst bed.

[0026] Furthermore, a pressure plate 105 is provided on the inner side of the tube sheet 107. The pressure plate 105 is fixed to the tube sheet 107 by bolts 104. A wire mesh 106 is provided between the pressure plate 105 and the end of the finned tube 110. The wire mesh 106 is used to press and cover the end of the finned tube 110 to prevent catalyst particles from entering the elliptical head 102 under the impact of airflow, while allowing the reaction gas to pass freely.

[0027] Furthermore, the finned tube 110 is an integral finned tube, in which the fins and the base tube are integrally formed. Compared with welded finned tubes, integral finned tubes have higher heat transfer efficiency, zero contact thermal resistance, better strength, and longer service life.

[0028] Furthermore, the upper elliptical end cap 102 is provided with a tube-side pressure gauge port 119 and a tube-side thermometer port 120 for monitoring the pressure and temperature of the tube-side reaction zone 125. The cylinder 109 is provided with a shell-side detection port 121 that communicates with the shell-side cavity 126 for monitoring the shell-side pressure and temperature.

[0029] Furthermore, the cylinder 109 is provided with a level gauge port 118 extending into the shell cavity 126 for monitoring the level of the heat transfer oil. The cylinder 109 is also provided with a vent port 123 and an oil drain port 124 communicating with the shell cavity 126, for initial venting and periodic replacement of the heat transfer oil, respectively.

[0030] Furthermore, the outer wall surface of the cylinder 109 is provided with a plurality of ear-type supports 112, which are arranged in a ring array to support and fix the reactor. The cylinder 109 is also provided with a manual valve port 117 for manual operation or sampling when necessary.

[0031] The operating method of the finned tube heat exchanger-type methanol catalytic synthesis reactor in this embodiment is as follows: S1. Catalyst loading: Before the reactor is put into use, the methanol synthesis catalyst is loaded into the tube side reaction zone 125 of each finned tube 110. After filling, the catalyst bed is pressed and fixed by the structure of the pressure plate 105 and the wire mesh 106 to prevent the catalyst particles from flowing or scattering under the action of airflow. At the same time, heat transfer oil is injected into the shell cavity 126, and the level of the heat transfer oil is monitored through the level gauge port 118. S2. Raw material gas intake and distribution: The raw material gas, which is a mixture of carbon monoxide and hydrogen, after being pressurized by the syngas compressor, enters the reactor through the syngas inlet 115 at the bottom. The gas is first initially distributed through the distribution pipe 101, then further evenly distributed through the perforated plate 103, and finally smoothly enters the tube side reaction zone 125 of each finned tube 110, flowing from bottom to top. S3. Reaction and heat exchange: During the upward process, the raw gas is first preheated to the reaction temperature by the high-temperature heat transfer oil circulating in the shell cavity 126 through the tube wall of the finned tube 110. Subsequently, a methanol synthesis reaction occurs in the catalyst bed within the tube reaction zone 125; Since the reaction is a strongly exothermic process, the large amount of heat released by the reaction is rapidly conducted through the tube wall of the finned tube 110 to the shell-side cavity 126 outside the tube, where it is absorbed by the heat transfer oil. The finned structure of the finned tube 110 significantly increases the heat exchange area, ensuring that the heat of reaction is removed in time and effectively preventing local overheating of the bed. S4. External circulation temperature control of heat transfer oil: The heat transfer oil whose temperature rises after absorbing the heat of reaction flows out of the reactor from the heat transfer oil outlet 114. High-temperature heat transfer oil enters the external cooler through the circulation pipeline, where it is cooled into a liquid state by cooling water. Subsequently, the liquid heat transfer oil enters the electric heater, which precisely reheats it according to the real-time temperature requirements of the reaction bed to achieve the set optimal inlet temperature. Finally, driven by the circulating pump, the heat transfer oil with precise temperature control returns from the heat transfer oil inlet 113 to the shell-side cavity 126 of the reactor to continue participating in heat exchange. This closed-loop circulation enables the continuous and stable removal of reaction heat and precise closed-loop control of the reaction bed temperature, which can effectively avoid the temperature sawtooth fluctuations common in cold-quench reactors, thus protecting the catalyst and improving reaction efficiency. Especially during equipment start-up and shutdown, load adjustment, or catalyst activity decay, the electric heater can actively compensate for heat and prevent the reaction bed from quenching or overheating. S5. Product discharge: The gas mixture after the reaction mainly contains methanol, unreacted CO and H2. This gas mixture is collected from the top of each finned tube 110 and discharged from the reactor through the synthesis gas outlet 116 in the upper elliptical head 102. It then enters the subsequent methanol cooler for cooling and is separated by a gas-liquid separator to obtain crude methanol liquid and unreacted circulating gas. S6. Process monitoring: The status of the tube-side reaction zone 125 is monitored in real time through the tube-side pressure gauge port 119 and the tube-side temperature gauge port 120. The pressure and temperature inside the shell-side cavity 126 are monitored through the shell-side detection port 121; the heat transfer oil level is monitored through the level gauge port 118. Vent 123, oil drain 124 and manual valve 117 provide necessary guarantees for the safe operation and maintenance of the system.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A finned tube heat exchange type methanol catalytic synthesis reactor, characterized in that, include: A cylindrical body (109) is provided with tube sheets (107) at its upper and lower ends respectively. Elliptical heads (102), the two elliptical heads (102) are respectively connected to the outside of the tube sheet (107) at the upper and lower ends of the cylinder (109) through equipment flanges (108); Multiple finned tubes (110) are fixed at their upper and lower ends to the upper and lower tube sheets (107), respectively. The internal space of the finned tubes (110) constitutes a tube-side reaction zone (125) for loading methanol synthesis catalyst. The shell-side cavity (126) is formed by the inner wall of the cylinder (109), the upper and lower tube sheets (107) and the outer wall of the finned tube (110), and the shell-side cavity (126) is used to contain heat transfer oil. A heat transfer oil inlet (113) and a heat transfer oil outlet (114) are provided on the cylinder (109) and communicate with the shell-side cavity (126); Syngas inlet (115) is located on the lower elliptical head (102) and is used to introduce raw material gas into the tube side reaction zone (125) of the finned tube (110). Syngas outlet (116) is provided on the elliptical head (102) above, for leading out the gas after reaction; And an external circulation temperature control system for heat transfer oil, the system comprising: A circulation pipeline connects the heat transfer oil outlet (114) and the heat transfer oil inlet (113). A cooler, provided on the circulation pipeline, is used to cool the heat transfer oil flowing out from the heat transfer oil outlet (114); An electric heater, installed on the circulation pipeline and located downstream of the cooler, is used to precisely reheat the cooled heat transfer oil; A circulation pump is used to drive the heat transfer oil to circulate between the shell-side cavity (126) and the external circulation temperature control system for the heat transfer oil.

2. The finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: The lower elliptical head (102) is provided with a gas distribution structure, which includes a distribution pipe (101) located above the synthesis gas inlet (115) and a horizontally mounted orifice plate (103). The distribution pipe (101) and the orifice plate (103) cooperate to distribute the raw material gas evenly to the tube side reaction zone (125) of each finned tube (110).

3. The finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: A pressure plate (105) is provided on the inner side of the tube sheet (107), and the pressure plate (105) is fixed to the tube sheet (107) by bolts (104); a wire mesh (106) is provided between the pressure plate (105) and the end of the finned tube (110), and the wire mesh (106) is used to press and cover the end of the finned tube (110) to prevent catalyst particles from entering the elliptical head (102).

4. The finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: The finned tube (110) is an integral finned tube, and its fins and base tube are integrally formed.

5. The finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: The upper elliptical head (102) is provided with a tube-side pressure gauge port (119) and a tube-side thermometer port (120).

6. The finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: The cylinder (109) is provided with a shell-side detection port (121) that communicates with the shell-side cavity (126).

7. The finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: The cylinder (109) is provided with a level gauge port (118) that extends into the shell cavity (126).

8. The finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: The cylinder (109) is also provided with a vent (123) and an oil drain (124) that communicate with the shell cavity (126).

9. A finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: The outer wall of the cylinder (109) is provided with a number of ear-type supports (112), which are arranged in a ring array.

10. A finned tube heat exchange type methanol catalytic synthesis reactor according to claim 1, characterized in that: The cylinder (109) is also provided with a manual valve port (117).

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