MTBE (Methyl Tert Butyl Ether) production device taking C4 as raw material

Abstract

The utility model belongs to the technical field of MTBE (Methyl Tert-Butyl Ether) production, and particularly relates to an MTBE production device taking C4 as a raw material. The MTBE production device taking C4 as the raw material comprises a raw material C4 pipeline and a methanol raw material tank, the raw material C4 pipeline is connected with a raw material preheater through a catalytic rectifying tower aftercooler, methanol in the methanol raw material tank is conveyed to the raw material preheater through a pipeline, an outlet of the raw material preheater is connected with an etherification reactor, and an outlet of the etherification reactor is connected with the methanol raw material tank. The etherification reactor is connected with a lower catalytic rectifying tower through a catalytic rectifying tower feeding heat exchanger and a catalytic rectifying tower preheater, and the lower catalytic rectifying tower is connected with an upper catalytic rectifying tower. According to the MTBE production device taking C4 as the raw material, the catalytic rectifying tower aftercooler and the tower bottom high-temperature MTBE raw material heat exchange system are arranged, so that a multi-stage waste heat recovery network is formed, steam condensate waste heat is used for preheating the raw material, the steam consumption is reduced, and energy conservation, consumption reduction and efficient utilization of resources are realized.

Description

Technical Field

[0001] This utility model belongs to the field of MTBE production technology, specifically relating to an MTBE production device using C4 as raw material. Background Technology

[0002] Methyl tert-butyl ether (MTBE) is generally synthesized from methanol and isobutylene using an acidic catalyst, with resin catalysts being the most commonly used in industry. Currently, the main C4 feedstock for MTBE production comes from oil refineries and ethylene cracking. In recent years, with the price of MTBE remaining high, isobutane dehydrogenation C4 has also become an important feedstock source.

[0003] Because the C4 temperature in the isobutane dehydrogenation unit is relatively low, only around 20°C, the conventional approach is to preheat the feed before it enters the reactor, consuming some of the steam.

[0004] CN206783562U discloses a MTBE production device and system with residual C4 reflux after extraction. By adding a residual C4 reflux pipeline, the low-temperature residual C4 separated from the methanol extraction tower is returned to the top of the catalytic distillation tower. Combined with equipment such as an air condenser and a reflux pump, the tower top temperature and energy consumption are effectively reduced, solving the problems of high energy consumption and unstable equipment operation caused by high temperature in the prior art. Its advantages are optimized heat balance, improved energy efficiency and device stability. However, its method of directly refluxing C4 cannot ensure the purity of the residual C4, and the risk of side reactions is relatively high. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an MTBE production device using C4 as raw material. This device includes a heat exchange system between the catalytic distillation column aftercooler and the high-temperature MTBE at the bottom of the column, combined with top-mounted vapor-phase air cooling precooling technology, forming a multi-stage waste heat recovery network. This effectively reduces circulating water consumption and steam heating load. Waste heat from the steam condensate is used for raw material preheating, further reducing reboiler steam consumption. Through cascaded utilization of thermal energy, equipment simplification, and emission control, energy saving, consumption reduction, and efficient resource utilization are achieved.

[0006] The MTBE production apparatus using C4 as a raw material according to this utility model includes a C4 feedstock pipeline and a methanol feedstock tank. C4 from the boundary area enters the catalytic distillation column aftercooler via the C4 feedstock pipeline for preheating. After preheating, it is transported via pipeline to the inlet of the feedstock preheater. Methanol from the methanol feedstock tank is also transported via pipeline to the inlet of the feedstock preheater. The methanol and C4 are preheated to the reaction temperature in the feedstock preheater. The outlet of the feedstock preheater is connected to the top of the etherification reactor, and a pipeline connected to the feed heat exchanger of the catalytic distillation column is installed at the bottom of the etherification reactor. The feed heat exchanger of the catalytic distillation column is connected to the preheater of the catalytic distillation column. The preheater of the catalytic distillation column is connected to the lower column of the catalytic distillation column. The top of the lower column of the catalytic distillation column is equipped with a pipeline connected to the upper column of the catalytic distillation column. The upper column of the catalytic distillation column is connected to the overhead air cooler of the catalytic distillation column. The overhead air cooler of the catalytic distillation column is connected to the reflux tank of the catalytic distillation column through the aftercooler of the catalytic distillation column. The reflux tank of the catalytic distillation column is equipped with a pipeline connected to the C4 water washing column. The bottom of the C4 water washing column is connected to the methanol recovery column through the feed heat exchanger of the methanol recovery column.

[0007] Preferably, the bottom of the lower column of the catalytic distillation column is connected to the feed heat exchanger of the catalytic distillation column. The feed heat exchanger of the catalytic distillation column is used for heat exchange between MTBE and the post-ether reaction materials. The feed heat exchanger of the catalytic distillation column is provided with a pipeline connected to the raw material preheater for conveying MTBE.

[0008] Preferably, a catalytic distillation column reboiler is provided at the bottom of the lower column of the catalytic distillation column. The catalytic distillation column reboiler is connected to a medium-pressure steam pipeline, and the medium-pressure steam serves as the heat source for the catalytic distillation column reboiler. The catalytic distillation column reboiler is connected to a catalytic distillation column preheater for conveying medium-pressure steam to exchange heat with the post-ether reaction material from the feed heat exchanger of the catalytic distillation column. The catalytic distillation column preheater is connected to a medium-pressure steam condensate pipeline for conveying the steam condensate generated after heat exchange.

[0009] Preferably, the bottom of the methanol recovery tower is connected to the methanol recovery tower reboiler, and the heat source of the methanol recovery tower reboiler is medium-pressure steam, which is used to heat the material at the bottom of the methanol recovery tower.

[0010] Preferably, the heat source for the methanol recovery tower feed heat exchanger is the extraction water collected from the bottom of the methanol recovery tower. The methanol recovery tower feed heat exchanger is equipped with a pipeline connected to the C4 water washing tower for transporting the extraction water. C4 material is collected from the top of the C4 water washing tower, and the upper part of the C4 water washing tower is connected to the demineralized water pipeline.

[0011] Preferably, the top of the methanol recovery tower is connected to the methanol recovery tower condenser, and the methanol recovery tower condenser is connected to the methanol recovery tower reflux tank. Part of the methanol condensate in the methanol recovery tower reflux tank is returned to the methanol recovery tower, and part of it is transported to the outside via the methanol recovery pipeline. The non-condensable vapor in the methanol recovery tower reflux tank is circulated to the methanol feedstock tank through the top pipeline to continue participating in the reaction.

[0012] Preferably, the methanol feedstock tank is equipped with a methanol feedstock inlet.

[0013] Preferably, the catalytic distillation column reflux tank is equipped with a pipeline for reflux to the upper column of the catalytic distillation column.

[0014] Preferably, the upper part of the catalytic distillation column is filled with bundled catalyst, which is a wire mesh packed catalyst.

[0015] Specifically, the MTBE production unit using C4 as raw material operates as follows: C4 from the boundary area enters the aftercooler of the catalytic distillation column, and its temperature rises after passing through the aftercooler. Methanol enters the methanol feed tank from the tank area outside the boundary area. The heated C4 and methanol are mixed and then further preheated in the feed preheater. The heat medium here is the high-temperature MTBE generated at the bottom of the catalytic distillation column. After preheating, it enters the etherification reactor for etherification reaction, that is, the reaction of isobutylene in C4 with methanol to produce MTBE. The material after the reaction is the post-etherification reaction material.

[0016] The post-ether reactants enter the feed heat exchanger of the catalytic distillation column. Heat exchange occurs between the post-ether reactants and MTBE flowing from the bottom of the catalytic distillation column. After heat exchange, the temperature of the post-ether reactants rises while the temperature of the MTBE decreases. The cooled MTBE then enters the feed preheater for further cooling before exiting the boundary zone. The heated post-ether reactants then enter the catalytic distillation column preheater for further heating, using the reboiler condensate as the heat transfer medium. A catalytic distillation column reboiler, heated by steam, is located at the bottom of the column. The heated condensate then enters the catalytic distillation column preheater as a heat source.

[0017] The heated etherified reactants enter the lower column of a catalytic distillation column for separation. High-purity MTBE is collected from the bottom of the lower column, while unreacted C4 and a small amount of methanol enter the upper column. In the upper column, unreacted isobutylene reacts further with methanol. The column is packed with bundled catalyst (wire mesh packing) which performs separation during the reaction, improving the isobutylene conversion rate. The gaseous material exiting from the top of the upper column first undergoes initial condensation in the top air cooler. The cooled material then enters the catalytic distillation column... The material is further cooled in the aftercooler of the distillation column. After cooling, the material enters the reflux tank of the catalytic distillation column, which is called post-ether C4. Part of the post-ether C4 is refluxed to the upper column of the catalytic distillation column, and the other part is transported to the C4 water washing column via pipeline for methanol extraction. The bundled catalyst is made of multiple layers of stainless steel wire mesh, with catalyst filling between each layer of wire mesh. A corrugated woven structure is used to form a regular packing layer. The size of the bundle matches the inner diameter of the upper column of the catalytic distillation column. Adjacent bundles are connected by a flange structure and a gradient packing method is used. The area near the top of the column does not need to be filled with catalyst, and only the wire mesh structure is used to achieve the separation effect.

[0018] Ethered C4 and water are in countercurrent contact in the C4 water washing tower. Methanol from the C4 enters the water. The top product of the tower is etherified C4. The material containing methanol and water in the bottom of the C4 water washing tower enters the feed heat exchanger of the methanol recovery tower for heat exchange. The heat source is the high-temperature extraction water at the bottom of the methanol recovery tower. The heated material enters the methanol recovery tower to recover the methanol. The gaseous material at the top of the methanol recovery tower is condensed into liquid phase by the methanol recovery tower condenser and enters the methanol recovery tower reflux tank. The extraction water generated at the bottom is returned to the C4 water washing tower for recycling. The non-condensable gases in the methanol recovery tower reflux tank are mainly C3, C4 and methanol. This part of the non-condensable gases is directly returned to the methanol feed tank. Part of the liquid phase in the methanol recovery tower reflux tank is returned to the methanol recovery tower, and part is transported to the outside through the methanol recovery pipeline. The methanol recovery tower reboiler with steam as the heat source is installed at the bottom of the methanol recovery tower.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] (1) The MTBE production device using C4 as raw material described in this utility model is equipped with a catalytic distillation column aftercooler. The liquid phase at the top of the catalytic distillation column after condensation is cooled by heat exchange with low-temperature raw material C4, which reduces the amount of circulating water used and the amount of steam consumed for preheating the raw material C4. At the same time, there is no need to install a C4 water cooler, which reduces equipment investment and energy consumption of the device.

[0021] (2) The MTBE production device using C4 as raw material described in this utility model is equipped with a catalytic distillation column feed heat exchanger and a catalytic distillation column preheater, which work together with the catalytic distillation column reboiler and raw material preheater to fully utilize the heat of steam and materials, reduce the amount of circulating water used, and reduce the energy consumption of the device.

[0022] (3) The MTBE production device using C4 as raw material described in this utility model introduces the non-condensable gas from the methanol recovery tower reflux tank to the methanol raw material tank, which not only ensures the positive pressure system of the methanol raw material tank, but also reduces the emission of non-condensable gas and reduces the loss of raw materials. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the MTBE production apparatus using C4 as raw material according to this utility model.

[0024] In the diagram: 1. Catalytic distillation column aftercooler; 2. Methanol feed tank; 3. Feed preheater; 4. Etherification reactor; 5. Catalytic distillation column feed heat exchanger; 6. Catalytic distillation column preheater; 7. Catalytic distillation column lower column; 8. Catalytic distillation column upper column; 9. Catalytic distillation column overhead air cooler; 10. Catalytic distillation column reflux tank; 11. Catalytic distillation column reboiler; 12. C4 water washing column; 13. Methanol recovery column feed heat exchanger; 14. Methanol recovery column; 15. Methanol recovery column condenser; 16. Methanol recovery column reflux tank; 17. Methanol recovery column reboiler; 18. Medium-pressure steam pipeline; 19. Medium-pressure steam condensate pipeline; 20. Methanol recovery pipeline; 21. Feed C4 pipeline; 22. Demineralized water pipeline. Detailed Implementation

[0025] The specific technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0026] like Figure 1As shown, the MTBE production unit using C4 as feedstock includes a catalytic distillation column aftercooler 1, which is connected to the C4 feedstock pipeline 21. The aftercooler 1 is also connected to the inlet of a feedstock preheater 3, which has a pipeline connected to a methanol feedstock tank 2 at its inlet. The preheater 3 outlet is connected to the top of an etherification reactor 4, and the bottom of the etherification reactor 4 has a pipeline connected to a catalytic distillation column feed heat exchanger 5. The catalytic distillation column feed heat exchanger 5 is connected to the catalytic distillation column preheater... The catalytic distillation column preheater 6 is connected to the lower column 7 of the catalytic distillation column. The top of the lower column 7 of the catalytic distillation column is provided with a pipeline connected to the upper column 8 of the catalytic distillation column. The upper column 8 of the catalytic distillation column is connected to the top air cooler 9 of the catalytic distillation column. The top air cooler 9 of the catalytic distillation column is connected to the reflux tank 10 of the catalytic distillation column through the aftercooler 1 of the catalytic distillation column. The reflux tank 10 of the catalytic distillation column is provided with a pipeline connected to the C4 water washing column 12. The bottom of the C4 water washing column 12 is connected to the methanol recovery column 14 through the methanol recovery column feed heat exchanger 13.

[0027] The bottom of the lower column 7 of the catalytic distillation column is connected to the feed heat exchanger 5 of the catalytic distillation column. MTBE and the post-ether reaction material exchange heat in the feed heat exchanger 5. The feed heat exchanger 5 of the catalytic distillation column is equipped with a pipeline connected to the raw material preheater 3 for conveying MTBE.

[0028] A catalytic distillation column reboiler 11 is installed at the bottom of the lower column 7 of the catalytic distillation column. The catalytic distillation column reboiler 11 is connected to the medium-pressure steam pipeline 18. The medium-pressure steam serves as the heat source for the catalytic distillation column reboiler 11. The catalytic distillation column reboiler 11 is connected to the catalytic distillation column preheater 6 for conveying medium-pressure steam to exchange heat with the post-ether reaction material from the catalytic distillation column feed heat exchanger 5. The catalytic distillation column preheater 6 is connected to the medium-pressure steam condensate pipeline 19 for conveying the steam condensate generated after heat exchange.

[0029] The bottom of the methanol recovery tower 14 is connected to the methanol recovery tower reboiler 17. The heat source of the methanol recovery tower reboiler 17 is medium-pressure steam, which is used to heat the material at the bottom of the methanol recovery tower 14.

[0030] The heat source for the methanol recovery tower feed heat exchanger 13 is the extraction water collected from the bottom of the methanol recovery tower 14. The methanol recovery tower feed heat exchanger 13 is equipped with a pipeline connected to the C4 water washing tower 12 for transporting the extraction water. C4 material is collected from the top of the C4 water washing tower 12, and the upper part of the C4 water washing tower 12 is connected to the demineralized water pipeline 22.

[0031] The top of the methanol recovery tower 14 is connected to the methanol recovery tower condenser 15, and the methanol recovery tower condenser 15 is connected to the methanol recovery tower reflux tank 16. Part of the methanol condensate in the methanol recovery tower reflux tank 16 is returned to the methanol recovery tower 14, and part of it is transported to the outside via the methanol recovery pipeline 20. The non-condensable vapor in the methanol recovery tower reflux tank 16 is circulated to the methanol feedstock tank 2 through the top pipeline to continue to participate in the reaction.

[0032] The methanol feedstock tank 2 is equipped with a raw methanol inlet.

[0033] The reflux tank 10 of the catalytic distillation column is equipped with a pipeline for reflux to the upper column 8 of the catalytic distillation column.

[0034] The upper column 8 of the catalytic distillation column is filled with bundled catalyst, which is a wire mesh packed catalyst.

[0035] The MTBE production unit using C4 as raw material has the following working process: C4 from the boundary area enters the aftercooler 1 of the catalytic distillation column. After passing through the aftercooler 1, the temperature rises. Methanol enters the methanol feed tank 2 from the tank area outside the boundary area. The heated C4 and methanol are mixed and enter the feed preheater 3 for further preheating. The heat medium here is the high-temperature MTBE generated in the lower column 7 of the catalytic distillation column. After preheating, it enters the etherification reactor 4 for etherification reaction, that is, the reaction of isobutylene in C4 with methanol to produce MTBE. The material after the reaction is the post-etherification reaction material.

[0036] The post-ether reactants enter the feed heat exchanger 5 of the catalytic distillation column. The post-ether reactants and MTBE flowing out from the bottom of the lower column 7 of the catalytic distillation column exchange heat exchanger 5 exchange heat. After heat exchange, the temperature of the post-ether reactants rises and the temperature of MTBE decreases. The cooled MTBE enters the feed preheater 3 for further cooling and then exits directly into the boundary zone. The heated post-ether reactants enter the catalytic distillation column preheater 6 for further heating. The heat medium is the condensate from the reboiler 11 of the catalytic distillation column. The reboiler 11 of the catalytic distillation column is installed at the bottom of the lower column 7 of the catalytic distillation column and is heated by steam. The heated condensate enters the catalytic distillation column preheater 6 as a heat source.

[0037] The heated etherified reaction product enters the lower column 7 of the catalytic distillation column, where separation takes place. High-purity MTBE is collected from the bottom of the lower column 7, while unreacted C4 and a small amount of methanol enter the upper column 8 of the catalytic distillation column. In the upper column 8, unreacted isobutylene reacts further with methanol. The column is packed with bundled catalyst. The gaseous product exiting from the top of the upper column 8 first enters the top air cooler 9 of the catalytic distillation column for initial condensation. The cooled product then enters the aftercooler 1 of the catalytic distillation column for further cooling. The reflux tank 10 of the catalytic distillation column is called post-etherified C4. Part of the post-etherified C4 is refluxed to the upper column 8 of the catalytic distillation column, and the other part is transported to the C4 water washing column 12 via pipeline for methanol extraction. The bundled catalyst is made of multiple layers of stainless steel wire mesh, with catalyst filling between each layer of wire mesh. A wavy woven structure is used to form a regular packing layer. The size of the bundle matches the inner diameter of the upper column 8 of the catalytic distillation column. Adjacent bundles are connected by a flange structure. A gradient packing method is used. The area near the top of the column does not need to be filled with catalyst, and only the wire mesh structure is used to achieve the separation effect.

[0038] Ethered C4 and water are in countercurrent contact in C4 water washing tower 12. Methanol in C4 enters the water. The top product of the tower is etherified C4. The material containing methanol and water in the bottom of C4 water washing tower 12 enters the feed heat exchanger 13 of methanol recovery tower for heat exchange. The heat source is the high-temperature extraction water at the bottom of methanol recovery tower 14. The heated material enters methanol recovery tower 14 to recover the methanol. The gaseous material at the top of methanol recovery tower 14 is condensed into liquid phase by methanol recovery tower condenser 15 and enters methanol recovery tower reflux tank 16. The extraction water generated at the bottom is returned to C4 water washing tower 12 for recycling. The non-condensable gas in methanol recovery tower reflux tank 16 is mainly C3, C4 and methanol. This part of the non-condensable gas is directly returned to methanol feed tank 2. Part of the liquid phase in methanol recovery tower reflux tank 16 is returned to methanol recovery tower 14, and part is transported to the outside through methanol recovery pipeline 20. A methanol recovery tower reboiler 17 with steam as the heat source is installed at the bottom of methanol recovery tower 14.

Claims

1. An MTBE production apparatus using C4 as raw material, characterized in that, The catalytic rectification tower rear cooler (1) is connected with the raw material C4 pipeline (21), the rectification tower rear cooler (1) is connected with the raw material preheater (3) inlet, the raw material preheater (3) inlet is provided with a pipeline connected with the methanol raw material tank (2), the raw material preheater (3) outlet is connected with the top of the etherification reactor (4), the bottom of the etherification reactor (4) is provided with a pipeline connected with the catalytic rectification tower feed heat exchanger (5), the catalytic rectification tower feed heat exchanger (5) is connected with the catalytic rectification tower preheater (6), the catalytic rectification tower preheater (6) is connected with the catalytic rectification tower lower tower (7), the top of the catalytic rectification tower lower tower (7) is provided with a pipeline connected with the catalytic rectification tower upper tower (8), the catalytic rectification tower upper tower (8) is connected with the catalytic rectification tower top air cooler (9), the catalytic rectification tower top air cooler (9) is connected with the catalytic rectification tower reflux tank (10) through the catalytic rectification tower rear cooler (1), the catalytic rectification tower reflux tank (10) is provided with a pipeline connected with the C4 water washing tower (12), the bottom of the C4 water washing tower (12) is connected with the methanol recovery tower (14) through the methanol recovery tower feed heat exchanger (13).

2. The MTBE production apparatus using carbon four as a raw material according to claim 1, wherein, The catalytic rectification tower lower tower (7) bottom is connected with the catalytic rectification tower feed heat exchanger (5), the MTBE in the catalytic rectification tower feed heat exchanger (5) exchanges heat with the ether post-reaction material, the catalytic rectification tower feed heat exchanger (5) is provided with a pipeline connected with the raw material preheater (3) for conveying the MTBE.

3. The MTBE production apparatus using carbon four as a raw material according to claim 1, wherein, The catalytic rectification tower lower tower (7) bottom is provided with the catalytic rectification tower reboiler (11), the catalytic rectification tower reboiler (11) is connected with the medium-pressure steam pipeline (18), the medium-pressure steam is used as the heat source of the catalytic rectification tower reboiler (11), the catalytic rectification tower reboiler (11) is connected with the catalytic rectification tower preheater (6) for conveying the medium-pressure steam, and heat exchange is carried out with the ether post-reaction material from the catalytic rectification tower feed heat exchanger (5); the catalytic rectification tower preheater (6) is connected with the medium-pressure steam condensate pipeline (19) for conveying the steam condensate generated after heat exchange.

4. The MTBE production apparatus using carbon four as a raw material according to claim 1, wherein, The bottom of the methanol recovery tower (14) is connected with the methanol recovery tower reboiler (17), the heat source of the methanol recovery tower reboiler (17) is the medium-pressure steam, and the methanol recovery tower reboiler (17) is used for heating the tower bottom material of the methanol recovery tower (14).

5. The MTBE production apparatus using carbon four as a raw material according to claim 1, wherein, The heat source of the methanol recovery tower feed heat exchanger (13) is the extraction water taken from the bottom of the methanol recovery tower (14), the methanol recovery tower feed heat exchanger (13) is provided with a pipeline connected with the C4 water washing tower (12) for conveying the extraction water, the C4 material is taken from the top of the C4 water washing tower (12), and the upper portion of the C4 water washing tower (12) is connected with the desalted water pipeline (22).

6. The MTBE production apparatus using carbon four as a raw material according to claim 1, wherein, The top of the methanol recovery tower (14) is connected with the methanol recovery tower condenser (15), the methanol recovery tower condenser (15) is connected with the methanol recovery tower reflux tank (16), the methanol condensate in the methanol recovery tower reflux tank (16) is partially refluxed to the methanol recovery tower (14), and part is conveyed to the out-of-bounds through the recovered methanol pipeline (20); the non-condensable gas in the methanol recovery tower reflux tank (16) is circulated to the methanol raw material tank (2) through the top pipeline, and continues to participate in the reaction.

7. The MTBE production apparatus using carbon four as a raw material according to claim 1, wherein The methanol raw material tank (2) is provided with a raw material methanol inlet.

8. The MTBE production apparatus using carbon four as a raw material according to claim 1, wherein, The catalytic rectification column reflux tank (10) is provided with a pipeline for reflux to the catalytic rectification column upper tower (8).

9. The MTBE production apparatus using carbon four as a raw material according to claim 1, wherein, The catalytic rectification column upper tower (8) is filled with bale catalyst, and the bale catalyst is a wire mesh packing type bale catalyst.

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