Methanol synthesis gas purification tank and methanol synthesis system

Abstract

The invention discloses a methanol synthesis gas purification tank and a methanol synthesis system. The methanol synthesis gas purification tank comprises a shell, an upper partition plate, a heat exchange assembly and a gas collecting pipe, wherein the upper partition plate, the heat exchange assembly and the gas collecting pipe are arranged in the shell; the methanol synthesis system comprises a methanol synthesis gas separator, a methanol synthesis gas compressor, a methanol synthesis gas purification tank, a first heat exchanger, a first methanol synthesis reactor, a first cooling unit, a first crude methanol separator, a second heat exchanger, a second methanol synthesis reactor, a second cooling unit, a second crude methanol separator and a first steam pocket; a second steam pocket and a steam superheater. The problem that the methanol synthesis gas purification tank and the preheating heat exchanger of the methanol synthesis gas purification tank are large in occupied area in the existing large methanol synthesis process can be solved, the problem of corrosion leakage of the heat exchange tube nest can be effectively solved, and the overhaul period is obviously prolonged compared with that of separate arrangement before.

Description

Technical Field

[0001] The present invention relates to the technical field of methanol synthesis, and in particular to a methanol synthesis gas purification tank and a methanol synthesis system. Background Art

[0002] my country's western region is rich in coal mineral resources, so a large number of modern coal chemical enterprises are located in the western region rich in coal mineral resources. The methanol synthesis process has an irreplaceable position in the production processes currently used in large-scale coal-to-olefin chemical projects in western my country.

[0003] For large-scale methanol synthesis technology, methanol synthesis gas is fresh methanol synthesis gas from upstream devices or sections, which needs to be pressurized and deeply purified before entering the methanol synthesis system; therefore, traditionally, the fresh synthesis gas sent from the outside first enters the synthesis gas separator for gas-liquid separation, and then is pressurized by the synthesis gas compressor. The pressurized methanol synthesis gas enters the synthesis gas purification tank preheater, and is heated to the temperature required by the catalyst of the methanol synthesis gas purification tank with the saturated steam produced as a by-product of the methanol synthesis drum, and then enters the methanol synthesis gas purification tank to remove the residual trace components that are toxic to the synthesis catalyst, such as sulfides. The methanol synthesis gas purification tank is filled with a purification catalyst. The methanol synthesis gas that has been deeply purified in the methanol synthesis gas purification tank subsequently enters the methanol synthesis reactor to prepare methanol.

[0004] For the current or traditional methanol synthesis process, the methanol synthesis gas purification tank used is an adiabatic fixed bed reactor and is equipped with a methanol synthesis gas purification tank preheating heat exchanger. The synthesis gas of the current or traditional methanol synthesis gas purification tank enters from the top of the purification tank and flows out from the bottom. There are problems such as large gas resistance of the entire methanol synthesis gas purification tank, large pressure drop of the flowing gas, and large power consumption of the entire system. Especially at the end of the use of the catalyst of the methanol synthesis gas purification tank or after several fluctuations in operating conditions, the problem of large power consumption of the system caused by the large resistance of the methanol alcohol synthesis gas purification tank is more serious. In addition, the methanol synthesis gas purification tank preheating heat exchanger with the methanol synthesis gas purification tank has a large footprint, and when steam is used as the heating medium, the heat exchanger tubes are prone to corrosion and leakage, which poses a major safety hazard. Summary of the invention

[0005] The main purpose of the present invention is to provide a methanol synthesis gas purification tank and a methanol synthesis system to solve the problem of short maintenance period of the methanol synthesis gas purification tank and its preheater in the existing large-scale methanol synthesis process.

[0006] To achieve one aspect of the above-mentioned invention object, the methanol synthesis gas purification tank provided by the present invention adopts the following technical scheme:

[0007] A methanol synthesis gas purification tank, comprising a shell and an upper baffle, a heat exchange component and a gas collecting pipe arranged in the shell; wherein:

[0008] The shell comprises an upper end cap, a lower end cap and a cylindrical section connected between the upper end cap and the lower end cap; the upper baffle is horizontally arranged in the methanol synthesis gas purification tank to separate the upper end cap and the cylindrical section, so as to form an upper end cap area between the upper end cap and the upper baffle, a cylindrical reaction area surrounded by the cylindrical section for loading a catalyst bed, and a lower end cap area formed by the lower end cap below the cylindrical reaction area for loading inert ceramic balls supporting the catalyst bed;

[0009] The shell forming the upper head and the cylindrical section is a double-layer structure having an inner layer and an outer layer, so that a first interlayer is formed between the inner layer and the outer layer of the upper head, and a second interlayer is formed between the inner layer and the outer layer of the cylindrical section; the first interlayer and the second interlayer are interconnected and together form a hollow interlayer of a gas flow channel; pores are evenly distributed on the inner layer of the shell of the upper head and the cylindrical section; an air inlet for introducing methanol synthesis gas to be purified is provided at the top of the upper head area, so that the methanol synthesis gas entering the upper head area enters the hollow interlayer through the pore distribution;

[0010] The upper end of the gas collecting pipe is closed, the lower end is open, and the pipe wall is provided with air holes, so that the gas in the cylindrical reactor passes through the air holes provided on the pipe wall of the gas collecting pipe and enters the gas collecting pipe; the gas collecting pipe is arranged along the central axis in the cylindrical reaction zone, and its lower end extends from the lower end of the lower head zone to discharge the gas in the gas collecting pipe;

[0011] The heat exchange assembly includes a plurality of heat exchange tubes, which are axially distributed in the cylindrical reaction zone between the inner layer of the shell and the gas collecting pipe to uniformly heat the catalyst bed in the cylindrical reaction zone.

[0012] In a preferred embodiment, the wall of the gas collecting pipe is a hollow double-layer structure, and the annular gap between the two layers is filled with inert ceramic balls to protect the pipe and reduce deformation when the gas pressure changes.

[0013] In a preferred embodiment, the upper head area is filled with inert ceramic balls.

[0014] In a preferred embodiment, the heat exchange tubes are divided into multiple groups, preferably 4-5 groups, and tube sheets are provided at both ends of each group.

[0015] In a preferred embodiment, the cylindrical reaction zone is filled with a catalyst for purifying methanol synthesis gas, and the catalyst is in a spherical shape with a diameter of 3-10 mm.

[0016] In a preferred embodiment, the inert ceramic ball has a diameter of 5-20 mm.

[0017] In a preferred embodiment, the heat exchange component is configured so that steam enters from the bottom of the heat exchange tubes and flows out from the top.

[0018] To achieve another aspect of the above-mentioned invention object, the methanol synthesis system provided by the present invention adopts the following technical scheme:

[0019] A methanol synthesis system, comprising:

[0020] Methanol synthesis gas separator, used to remove water from methanol synthesis gas;

[0021] A methanol synthesis gas compressor, the methanol synthesis gas compressor comprising a methanol synthesis gas compressor synthesis section, the methanol synthesis gas compressor synthesis section is used to pressurize the methanol synthesis gas from the methanol synthesis gas separator;

[0022] The methanol synthesis gas purification tank according to any one of claims 1 to 7, used for purifying the methanol synthesis gas pressurized by the synthesis section of the methanol synthesis gas compressor to obtain purified synthesis gas;

[0023] A first heat exchanger is used to heat and heat up the mixed gas of the first part of the purified synthesis gas and the gas phase separated by the second crude methanol separator with the reaction product from the first methanol synthesis reactor;

[0024] a first methanol synthesis reactor, used for synthesizing methanol using the mixed gas from the first heat exchanger;

[0025] a first cooling unit, used for condensing the reaction product from the first heat exchanger to obtain a first condensed product;

[0026] a first crude methanol separator, used for performing gas-liquid separation on the first condensed product to obtain first crude methanol as a liquid phase and first non-condensable gas as a gas phase;

[0027] The methanol synthesis gas compressor further comprises a methanol synthesis gas compressor circulation section for pressurizing a mixed gas of the second portion of the purified synthesis gas and the gas phase from the first crude methanol separator;

[0028] The second heat exchanger is used to heat and heat up the mixed gas pressurized by the methanol synthesis gas compressor circulation section with the reaction product from the second methanol synthesis reactor;

[0029] a second methanol synthesis reactor, used for synthesizing methanol using the mixed gas from the second heat exchanger;

[0030] a second cooling unit, used for condensing the reaction product from the second heat exchanger to obtain a second condensed product;

[0031] a second crude methanol separator, for performing gas-liquid separation on the second condensed product to obtain a second crude methanol as a liquid phase and a second non-condensable gas as a gas phase;

[0032] A first steam drum, used to remove heat generated by the first methanol synthesis reactor and obtain first steam;

[0033] A second steam drum, used to remove heat generated by the second methanol synthesis reactor and obtain second steam;

[0034] The steam superheater is used to heat the first steam and the second steam to obtain superheated steam, and at least part of the superheated steam is sent to the heat exchange component of the methanol synthesis gas purification tank as a heat source.

[0035] In a preferred embodiment, the first cooling unit comprises a first air cooler and a first water cooler connected in sequence;

[0036] The second cooling unit comprises a second air cooler and a second water cooler connected in sequence;

[0037] In a preferred embodiment, the methanol synthesis system further comprises:

[0038] A crude methanol flash tank, used for flash separation of the first crude methanol and the second crude methanol;

[0039] The medium-pressure steam flash tank is used to flash the steam discharged from the heat exchange component, and to send the obtained liquid condensate to the process condensate system and the vapor phase steam to the low-pressure steam pipeline network.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] (1) The methanol synthesis gas purification tank and the methanol synthesis system of the present invention can solve the problem of large floor space occupied by the methanol synthesis gas purification tank and the preheating heat exchanger in the existing large-scale methanol synthesis process by integrating the heat exchange component in the purification tank; in addition, by making the methanol synthesis gas fully buffered, dispersed and preheated in the purification tank, and cooperating with the heat storage effect of the superheated steam and the catalyst bed itself, the problem of corrosion and leakage of the heat exchange tubes can be effectively solved, and the maintenance cycle of the methanol synthesis gas purification tank and its preheater is significantly extended compared with the previous separate arrangement;

[0042] (2) The purification tank of the present invention is designed so that the flow of the airflow in the catalyst bed changes from longitudinal to transverse, the flow path becomes shorter, and the pressure drop is significantly reduced. During operation, the pressure drop can be greatly reduced compared with the traditional axial adiabatic fixed bed, and the power required by the methanol synthesis compressor is greatly reduced. At the same time, due to the sufficient buffering and dispersion of the airflow in the upper head area and the middle interlayer, the problem of a significant increase in the resistance of the catalyst bed at the end of use caused by the hammering of the catalyst bed by the air hammer due to operating condition fluctuations can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of the methanol synthesis gas purification tank of the present invention;

[0044] Figure 2 It is a schematic diagram of the process of the methanol synthesis system of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0046] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] In the methanol synthesis process, before the methanol synthesis gas is sent to the methanol synthesis reactor, it first needs to enter the methanol synthesis gas purification tank to remove the residual trace components that are toxic to the synthesis catalyst, such as sulfides. The methanol synthesis gas purification tank is filled with a purification catalyst. The methanol synthesis gas that has been deeply purified by the methanol synthesis gas purification tank subsequently enters the methanol synthesis reactor to prepare methanol.

[0049] like Figure 1 As shown, the methanol synthesis gas purification tank 4 of the present invention includes a shell and an upper partition A5, a heat exchange component A2 and a gas collecting pipe A10 arranged in the shell; wherein,

[0050] The shell includes an upper head A11, a lower head A33 and a cylindrical section A22 connected between the upper head and the lower head; the upper partition A5 is horizontally arranged in the methanol synthesis gas purification tank to separate the upper head A11 and the cylindrical section A22, thereby forming an upper head area A3 between the upper head and the upper partition, a cylindrical reaction area A8 surrounded by the cylindrical section for loading a catalyst bed, and a lower head area A9 formed by the lower head below the cylindrical reaction area for loading ceramic balls supporting the catalyst bed, that is, inert ceramic balls are loaded in the lower head area to support the catalyst bed above, such as inert ceramic balls with a diameter of 5-20 mm.

[0051] The shell forming the upper head and the cylindrical section is a double-layer structure with an inner layer and an outer layer, so that a first interlayer A4 is formed between the inner layer and the outer layer of the upper head, and a second interlayer A6 is formed between the inner layer and the outer layer of the cylindrical section; the first interlayer and the second interlayer are interconnected and together form a hollow interlayer of the gas flow channel; pores (not shown in the figure) are evenly distributed on the inner layer of the shell of the upper head and the cylindrical section; an air inlet A1 for introducing methanol synthesis gas to be purified is provided at the top of the upper head area, so that the methanol synthesis gas entering the upper head area enters the hollow interlayer through the distributed pores.

[0052] In a preferred embodiment, the upper head area is filled with inert ceramic balls to further buffer and disperse the incoming gas J.

[0053] The upper end of the gas collecting pipe A10 is closed, the lower end is open, and air holes are provided on the tube wall, so that the gas in the cylindrical reactor can pass through the air holes on the tube wall of the gas collecting pipe and enter the gas collecting pipe; the gas collecting pipe is arranged along the central axis in the cylindrical reaction zone and its lower end extends from the lower end of the lower head zone to discharge the gas in the gas collecting pipe; of course, a catalyst unloading port can be further provided at the bottom of the lower head.

[0054] In a preferred embodiment, the wall of the gas collecting pipe is a hollow double-layer structure, and the annular gap between the two layers is filled with inert ceramic balls, such as inert ceramic balls with a diameter of 5-20 mm, so as to protect the pipe from deformation when the gas pressure changes. The purified methanol synthesis gas enters the gas collecting pipe from the periphery of the annular gas collecting pipe and is discharged.

[0055] The heat exchange assembly A2 includes a plurality of heat exchange tubes A7, which are axially distributed in the cylindrical reaction zone A8 between the inner layer of the shell and the gas collecting pipe to uniformly heat the catalyst bed in the cylindrical reaction zone. Of course, it can be understood in the art that, in order to facilitate the entry of steam, the heat exchange tubes are divided into multiple groups, preferably 4-5 groups, and tube sheets are provided at both ends of each group. Furthermore, the number of heat exchange tubes can be 1500-3000, and the methanol synthesis gas purification catalyst can be arranged in the gap between the tubes, and the catalyst can be spherical with a diameter of 3-10 mm.

[0056] In some embodiments, thermocouples or thermal resistance thermometers may be arranged between the heat exchange tubes of the methanol synthesis gas purification tank, and the thermometers are arranged from the inside to the outside to detect the use of the catalyst. Furthermore, online monitoring instruments may be arranged on the inlet gas pipeline and the outlet gas pipeline of the methanol synthesis gas purification tank to monitor the use of the catalyst.

[0057] During operation, the methanol synthesis gas enters the upper head area A3 for buffering through the air inlet A1, and then enters the hollow interlayer after passing through the pore distribution of the inner layer of the upper head. Since the hollow interlayer is relatively thin (for example, the thickness is 1 / 10-1 / 20 of the radius of the cylindrical reaction zone) and the contact area with the cylindrical reaction zone A8 is large, the methanol synthesis gas can be fully preheated, and then enter the catalyst bed in the cylindrical reaction zone after passing through the pore distribution of the inner layer of the cylindrical section A22; in the cylindrical reaction zone A8, the contact temperature difference between the methanol synthesis gas and the heat exchange tubes is relatively low, so that the steam in the tube is not easy to condense. Accordingly, the distributed heat exchange tubes A7 can fully heat the catalyst bed and the methanol synthesis gas to promote the reaction; the methanol synthesis gas purified by the catalyst bed reaction passes through the tube wall of the gas collecting pipe A10 and enters the gas collecting pipe and is finally discharged from the methanol synthesis gas purification tank from the bottom of the lower head.

[0058] Specifically, in Figure 1 In the embodiment shown, the operation implementation process of the methanol synthesis gas purification tank includes the following steps:

[0059] Step S1: Superheated steam enters the heat exchange tube A7 from the bottom through the tube sheet, and the steam is discharged from the top after heat exchange, while the catalyst bed A8 is heated to the temperature required by the process, for example: 150-190°C;

[0060] Step S2: methanol synthesis gas enters from the gas inlet A1;

[0061] Step S3: After the methanol synthesis gas enters the upper header area A3 for buffering, it is distributed through the inert porcelain balls with a diameter of 5-20 mm filled there;

[0062] Step S4: the methanol synthesis gas after gas distribution enters the first interlayer A4 through the pores distributed on the inner layer of the upper head area;

[0063] Step S5: After the methanol synthesis gas enters the first interlayer A4, it flows downward and enters the second interlayer A6;

[0064] Step S6: After the methanol synthesis gas enters the second interlayer A6, it enters the catalyst bed A8 laterally from the distribution holes in the inner layer of the cylindrical section to perform a methanol synthesis gas purification reaction;

[0065] Step S7: After being catalytically purified by the catalyst bed A8, the methanol synthesis gas passes through the interlayer of the gas collecting pipe wall, enters the middle gas collecting pipe A10 and is sent out from the bottom methanol synthesis gas outlet.

[0066] like Figure 2 As shown, the methanol synthesis system of the present invention includes a methanol synthesis gas separator 2, a methanol synthesis gas compressor 21, a methanol synthesis gas purification tank 4, a first heat exchanger 5, a first methanol synthesis reactor 6, a first cooling unit, a first crude methanol separator 9, a second heat exchanger 11, a second methanol synthesis reactor 12, a second cooling unit, a second crude methanol separator 15, a first steam drum 23, a second steam drum 25 and a steam superheater 26.

[0067] The methanol synthesis gas separator 2 is used to separate the methanol synthesis gas 1 into gas and liquid, remove water from the methanol synthesis gas, and ensure the normal operation of the subsequent compressor, which is well known in the art and will not be described in detail here.

[0068] The methanol synthesis gas compressor comprises a methanol synthesis gas compressor synthesis section 3 and a methanol synthesis gas compressor circulation section 10; wherein the methanol synthesis gas compressor synthesis section 3 is connected to a methanol synthesis gas separator 2 for pressurizing the methanol synthesis gas from the methanol synthesis gas separator.

[0069] The methanol synthesis gas purification tank 4 is connected to the methanol synthesis gas compressor synthesis section 3 and is used for purifying the methanol synthesis gas pressurized by the methanol synthesis gas compressor synthesis section to obtain purified synthesis gas.

[0070] The first heat exchanger 5 is used to heat the mixed gas of the first part of the purified synthesis gas and the gas phase separated by the second crude methanol separator 15 with the reaction products from the first methanol synthesis reactor 6 to increase the temperature; for example, the purified synthesis gas leaving the methanol synthesis gas purification tank is divided into two streams, of which the first stream is mixed with the gas phase separated by the second crude methanol separator and then enters the first heat exchanger to exchange heat with the reaction products leaving the first methanol synthesis reactor to recover the heat of the reaction products.

[0071] The first methanol synthesis reactor 6 is used to synthesize methanol using the mixed gas from the first heat exchanger 5. The specific methanol synthesis reaction is well known in the art and will not be described in detail here.

[0072] The first cooling unit is used to condense the reaction product from the first heat exchanger 5 to obtain a first condensed product; in one embodiment, the first cooling unit includes a first air cooler 7 and a first water cooler 8 connected in sequence, which are used to sequentially cool the reaction product after heat is recovered by the first heat exchanger.

[0073] The first crude methanol separator 9 is connected to the first cooling unit and is used for performing gas-liquid separation on the first condensed product to obtain the first crude methanol as the liquid phase and the first non-condensable gas as the gas phase.

[0074] The methanol synthesis gas compressor circulation section 10 is used to pressurize the mixed gas of the second part of the purified synthesis gas and the gas phase from the first crude methanol separator 9 .

[0075] The second heat exchanger 11 is used to heat-exchange and heat-raise the mixed gas pressurized by the methanol synthesis gas compressor circulation section 10 with the reaction product from the second methanol synthesis reactor 12 to recover the heat in the reaction product.

[0076] The second methanol synthesis reactor 12 is connected to the second heat exchanger 11 and is used to synthesize methanol using the mixed gas from the second heat exchanger. The specific methanol synthesis reaction is well known in the art and will not be described in detail here.

[0077] The second cooling unit is used to condense the reaction product from the second heat exchanger to obtain a second condensed product. In one embodiment, the second cooling unit includes a second air cooler 13 and a second water cooler 14 connected in sequence to sequentially cool the reaction product after heat is recovered by the second heat exchanger.

[0078] The second crude methanol separator 15 is connected to the second cooling unit and is used for performing gas-liquid separation on the second condensed product to obtain the second crude methanol as the liquid phase and the second non-condensable gas as the gas phase.

[0079] The first steam drum 23 is used to remove the heat generated by the first methanol synthesis reactor 6 and obtain the first steam; the second steam drum 25 is used to remove the heat generated by the second methanol synthesis reactor 12 and obtain the second steam; the first steam drum 23 and the second steam drum 25 are respectively supplied with boiler water by the first boiler water pipeline 22 and the second boiler water pipeline 24.

[0080] The steam superheater 26 is connected to the first steam drum 23 and the second steam drum 25 respectively, and is used to heat the first steam and the second steam to obtain superheated steam, and at least part of the superheated steam is sent to the heat exchange component of the methanol synthesis gas purification tank 4 as a heat source to provide heat.

[0081] In some embodiments, the methanol synthesis system also includes a crude methanol flash tank 16 and a medium-pressure steam flash tank 30: wherein the crude methanol flash tank is used to flash and separate the first crude methanol and the second crude methanol; the medium-pressure steam flash tank is used to flash the steam discharged from the heat exchange component, and the obtained liquid condensate is sent to the process condensate system, and the vapor phase steam is incorporated into the low-pressure steam pipeline network.

[0082] During operation, the methanol synthesis gas passes through the upstream transmission pipeline 1, enters the methanol synthesis gas separator 2 for gas-liquid separation, and then enters the synthesis section 3 of the methanol synthesis compressor for pressurization. The pressurized methanol synthesis gas enters the methanol synthesis gas purification tank 4 for purification to obtain purified synthesis gas, wherein the operating temperature of the methanol synthesis gas purification tank 4 is set according to the use of the catalyst, for example: 150-190°C;

[0083] The purified synthesis gas from the methanol synthesis gas purification tank 4 is divided into two streams: one stream is merged with the gas phase separated by the second crude methanol separator 15 and then enters the first intermediate heat exchanger 5 for heat exchange and temperature increase, and then enters the first methanol synthesis reactor 6 for methanol synthesis, after which the reaction product enters the first intermediate heat exchanger 5 for cooling, and then enters the first air cooler 7 and the first water cooler 8 in sequence for further cooling and condensation, and the condensed reaction product enters the first crude methanol separator 9 for gas-liquid separation to obtain the first crude methanol;

[0084] The gas phase outlet of the first crude methanol separator 9 merges with another stream of purified synthesis gas from the methanol synthesis gas purification tank 4, enters the methanol synthesis gas compressor circulation section 10 for pressurization, enters the second intermediate heat exchanger 11 for temperature increase after pressurization, and then enters the second methanol synthesis reactor 12 for methanol synthesis. After that, the reaction product enters the second intermediate heat exchanger 11, and then enters the second air cooler 13 and the second water cooler 14 in sequence for further cooling and condensation. After cooling and heating, it enters the second crude methanol separator 15 for separation to obtain the second crude methanol. The first crude methanol and the second crude methanol enter the crude methanol flash tank 16 for flash treatment, and the flash gas enters the crude methanol discharge tank 17 to recover the methanol therein.

[0085] Methanol synthesis reaction is carried out in the first methanol synthesis reactor 6 and the second methanol synthesis reactor 12, while a large amount of heat is released. In order to remove the generated heat, a first steam drum 23 and a second steam drum 25 are provided. The first steam drum 23 and the second steam drum 25 are supplied with boiler water by the first boiler water pipeline 22 and the second boiler water pipeline 24.

[0086] The by-product steam produced by the first steam drum 23 and the second steam drum 25 is saturated steam, which enters the steam superheater 26. The by-product steam after superheating is divided into two streams, one as external steam 27, and the other enters the above-mentioned methanol synthesis gas purification tank 4 for heating. The steam heated in the methanol synthesis gas purification tank 4 enters the medium-pressure flash tank 30, and the condensate after separation in the medium-pressure flash tank enters the low-pressure steam network as external process condensate 28 and low-pressure steam 29.

[0087] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention.

Claims

1. A methanol synthesis gas purification tank, characterized in that: The methanol synthesis gas purification tank comprises a shell and an upper baffle, a heat exchange component and a gas collecting pipe arranged in the shell; wherein, The shell comprises an upper end cap, a lower end cap and a cylindrical section connected between the upper end cap and the lower end cap; the upper baffle is horizontally arranged in the methanol synthesis gas purification tank to separate the upper end cap and the cylindrical section, so as to form an upper end cap area between the upper end cap and the upper baffle, a cylindrical reaction area surrounded by the cylindrical section for loading a catalyst bed, and a lower end cap area formed by the lower end cap below the cylindrical reaction area for loading inert ceramic balls supporting the catalyst bed; The shell forming the upper head and the cylindrical section is a double-layer structure having an inner layer and an outer layer, so that a first interlayer is formed between the inner layer and the outer layer of the upper head, and a second interlayer is formed between the inner layer and the outer layer of the cylindrical section; the first interlayer and the second interlayer are interconnected and together form a hollow interlayer of the gas flow channel; The inner layer of the shell of the upper head and the cylindrical section is evenly distributed with air holes; the top of the upper head area is provided with an air inlet for introducing the methanol synthesis gas to be purified, so that the methanol synthesis gas entering the upper head area enters the hollow interlayer through the air holes; The upper end of the gas collecting pipe is closed, the lower end is open, and the pipe wall is provided with air holes, so that the gas in the cylindrical reactor passes through the air holes provided on the pipe wall of the gas collecting pipe and enters the gas collecting pipe; the gas collecting pipe is arranged along the central axis in the cylindrical reaction zone, and its lower end extends from the lower end of the lower head zone to discharge the gas in the gas collecting pipe; The heat exchange assembly includes a plurality of heat exchange tubes, which are axially distributed in the cylindrical reaction zone between the inner layer of the shell and the gas collecting pipe to uniformly heat the catalyst bed in the cylindrical reaction zone.

2. The methanol synthesis gas purification tank according to claim 1, characterized in that: The pipe wall of the gas collecting pipe is a hollow double-layer structure, and the annular gap between the two layers is filled with inert porcelain balls.

3. The methanol synthesis gas purification tank according to claim 1 or 2, characterized in that: The upper head area is filled with inert porcelain balls.

4. The methanol synthesis gas purification tank according to any one of claims 1 to 3, characterized in that: The heat exchange tubes are divided into multiple groups, preferably 4-5 groups, and tube sheets are provided at both ends of each group.

5. The methanol synthesis gas purification tank according to any one of claims 1 to 4, characterized in that: The cylindrical reaction zone is filled with a catalyst for purifying methanol synthesis gas, and the catalyst is in a spherical shape with a diameter of 3-10 mm.

6. The methanol synthesis gas purification tank according to any one of claims 1 to 5, characterized in that: The diameter of the inert porcelain ball is 5-20 mm.

7. The methanol synthesis gas purification tank according to any one of claims 1 to 6, characterized in that: The heat exchange component is configured so that steam enters from the bottom of the heat exchange tubes and flows out from the top.

8. A methanol synthesis system, comprising: Methanol synthesis gas separator, used to remove water from methanol synthesis gas; A methanol synthesis gas compressor, the methanol synthesis gas compressor comprising a methanol synthesis gas compressor synthesis section, the methanol synthesis gas compressor synthesis section is used to pressurize the methanol synthesis gas from the methanol synthesis gas separator; The methanol synthesis gas purification tank according to any one of claims 1 to 7, used for purifying the methanol synthesis gas pressurized by the synthesis section of the methanol synthesis gas compressor to obtain purified synthesis gas; A first heat exchanger is used to heat and heat up the mixed gas of the first part of the purified synthesis gas and the gas phase separated by the second crude methanol separator with the reaction product from the first methanol synthesis reactor; a first methanol synthesis reactor, used for synthesizing methanol using the mixed gas from the first heat exchanger; a first cooling unit, used for condensing the reaction product from the first heat exchanger to obtain a first condensed product; a first crude methanol separator, used for performing gas-liquid separation on the first condensed product to obtain first crude methanol as a liquid phase and first non-condensable gas as a gas phase; The methanol synthesis gas compressor further comprises a methanol synthesis gas compressor circulation section for pressurizing a mixed gas of the second portion of the purified synthesis gas and the gas phase from the first crude methanol separator; The second heat exchanger is used to heat and heat up the mixed gas pressurized by the methanol synthesis gas compressor circulation section with the reaction product from the second methanol synthesis reactor; a second methanol synthesis reactor, used for synthesizing methanol using the mixed gas from the second heat exchanger; a second cooling unit, used for condensing the reaction product from the second heat exchanger to obtain a second condensed product; a second crude methanol separator, for performing gas-liquid separation on the second condensed product to obtain a second crude methanol as a liquid phase and a second non-condensable gas as a gas phase; A first steam drum, used to remove heat generated by the first methanol synthesis reactor and obtain first steam; A second steam drum, used to remove heat generated by the second methanol synthesis reactor and obtain second steam; The steam superheater is used to heat the first steam and the second steam to obtain superheated steam, and at least part of the superheated steam is sent to the heat exchange component of the methanol synthesis gas purification tank as a heat source.

9. The methanol synthesis system according to claim 8, characterized in that: The first cooling unit comprises a first air cooler and a first water cooler connected in sequence; The second cooling unit includes a second air cooler and a second water cooler which are connected in sequence.

10. The methanol synthesis system according to claim 8 or 9, characterized in that: The methanol synthesis system also includes: A crude methanol flash tank, used for flash separation of the first crude methanol and the second crude methanol; The medium-pressure steam flash tank is used to flash the steam discharged from the heat exchange component, and to send the obtained liquid condensate to the process condensate system and the vapor phase steam to the low-pressure steam pipeline network.

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