Process system for producing dimethyl ether
By combining a fluidized bed reactor and a regenerator, the problems of hot spot formation and catalyst carbon buildup in fixed bed reactors were solved, achieving high selectivity and high yield production of dimethyl ether, extending catalyst life, and reducing production costs.
Patent Information
- Application Number
- CN202520401844.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-07
- Publication Date
- 2026-01-16
- Estimated Expiration
- 2035-03-07
AI Technical Summary
The production of dimethyl ether from methanol dehydration in existing fixed-bed reactors suffers from hot spot formation, catalyst carbon buildup, reduced activity, and short service life, leading to decreased dimethyl ether selectivity and yield, and increased production costs.
The process system employs a fluidized bed reactor combined with a regenerator, utilizing the fluidized catalyst for heat transfer. It is equipped with external heat exchangers for the reaction and regeneration, and combines a cyclone separator and a regenerator to burn off and regenerate the catalyst, thereby achieving catalyst recycling and heat recovery.
It improves the selectivity and yield of dimethyl ether, extends catalyst life, reduces production costs and energy consumption, and has the advantages of high operational flexibility, high heat utilization, and short start-up time.
Smart Images
Figure CN223800496U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to dimethyl ether production technical field especially relates to a process system for producing dimethyl ether. BACKGROUND
[0002] Dimethyl ether is a multipurpose chemical, which is mainly used as clean fuel and chemical raw material, and is widely used in fuel, chemical industry, refrigeration and other fields, especially in the production of olefins, aromatic hydrocarbons and other key compounds, and gradually replaces the increasingly reduced petrochemical energy, becomes the important raw material in chemical industry, has important economic and environmental protection value.
[0003] At present, the main process technology of domestic dimethyl ether production includes methanol dehydration method, that is, using fixed bed methanol dehydration to produce dimethyl ether. However, there are the following defects in using fixed bed methanol dehydration to produce dimethyl ether:
[0004] 1. In the fixed bed reactor, the reaction of methanol dehydration to generate dimethyl ether is an exothermic reaction. Because the catalyst in the fixed bed is fixed, the heat transfer is relatively poor, and hot spots are easily formed in the catalyst bed layer. The temperature is too high at the hot spot, which can increase the side reaction, such as the decomposition of methanol to generate carbon monoxide and hydrogen, etc., reduce the selectivity and yield of dimethyl ether, and also can accelerate the aging and deactivation of catalyst due to overheating, shorten the service life of catalyst;
[0005] 2. Using fixed bed reactor for methanol dehydration to produce dimethyl ether, carbon deposition is easy to occur on the surface of catalyst, which can cover the active sites of catalyst, hinder the contact between reactants and catalyst, and gradually reduce the activity of catalyst. Therefore, catalyst regeneration is needed regularly, which increases the production cost and the downtime of device. In the long-term reaction process, due to the influence of reaction pressure, temperature and other factors, the activity of catalyst will gradually decrease, which leads to the decrease of methanol conversion rate and dimethyl ether selectivity, and the operation conditions need to be optimized or the catalyst needs to be replaced to maintain the production efficiency and product quality. UTILITY MODEL CONTENT
[0006] The utility model aims at providing a process system for producing dimethyl ether, which has the advantages of less side reaction, good reaction efficiency, high conversion rate, long service life of catalyst in the system and continuous production.
[0007] The technical scheme for solving the above technical problem is: a process system for producing dimethyl ether, which comprises a fluidized bed reactor provided with a reaction rough rotor in the upper inner cavity, a methanol input pipeline connected to the lower side wall of the fluidized bed reactor, and a methanol preheater, a methanol vaporizer and a methanol superheater arranged in sequence along the methanol flow direction on the methanol input pipeline;
[0008] The fluidized bed reactor is connected with a gas output pipeline on the top, and a reaction cyclone, a cooler and a separator are sequentially arranged on the gas output pipeline along the gas flow direction, and the separator is connected with a product separation tower through a liquid phase output pipeline.
[0009] The fluidized bed reactor is further provided with a regenerator for regenerating the deactivated catalyst in the fluidized bed reactor.
[0010] As a further improvement of the utility model, the methanol vaporizer and the methanol superheater are both pipe heat exchangers, the gas output pipeline between the reaction cyclone and the cooler passes through the heat exchange pipes of the methanol vaporizer and the methanol superheater, and a switch valve A is further arranged on the gas output pipeline between the methanol vaporizer and the methanol superheater.
[0011] As a further improvement of the utility model, a low-pressure steam input pipe is further connected with the gas output pipeline between the switch valve A and the methanol vaporizer, and a switch valve B is arranged on the low-pressure steam input pipe.
[0012] As a further improvement of the utility model, a heating furnace is further arranged on one side of the methanol superheater, a three-way switch valve is arranged on the methanol input pipeline between the methanol vaporizer and the methanol superheater, and the gas inlet end of the heating furnace is connected with the three-way switch valve through a branch pipeline, and the gas outlet end of the heating furnace is connected with the methanol input pipeline between the methanol superheater and the fluidized bed reactor through a branch pipeline.
[0013] As a further improvement of the utility model, a reaction external heat exchanger is connected with the fluidized bed reactor.
[0014] As a further improvement of the utility model, the reaction coarse cyclone is a two-stage cyclone separator arranged in multiple groups.
[0015] As a further improvement of the utility model, a regeneration external heat exchanger is connected with the regenerator.
[0016] As a further improvement of the utility model, a regeneration coarse cyclone is arranged in the upper cavity of the regenerator, and the regeneration coarse cyclone is a two-stage cyclone separator arranged in multiple groups.
[0017] As a further improvement of the utility model, a regeneration fine cyclone is connected with the regenerator through a pipeline.
[0018] As a further improvement of the utility model, the separator is connected with the methanol input pipeline between the methanol superheater and the fluidized bed reactor through a gas phase output pipeline.
[0019] Advantages
[0020] Compared with the prior art, the process system for producing dimethyl ether has the following advantages:
[0021] 1. This process system uses a fluidized bed reactor, which has the advantages of easy operation and high operational flexibility. Simultaneously, the fluidized bed reactor is connected to a regenerator. After the reaction, the deactivated catalyst carrying coke enters the regenerator for coke burn-off and regeneration. The regenerated catalyst, now reactivated, re-enters the fluidized bed reactor, forming a two-stage catalyst fluidization process, thereby extending the catalyst's lifespan. Furthermore, the reaction of methanol dehydration to produce dimethyl ether is exothermic. Because the catalyst in the fluidized bed reactor is fluidized, heat transfer is relatively good, thus preventing the formation of hot spots in the catalyst bed, avoiding increased side reactions, improving the selectivity and yield of dimethyl ether, and preventing accelerated aging and deactivation of the catalyst due to overheating.
[0022] 2. In the initial stage of operation, the methanol vaporizer uses low-pressure steam to vaporize the preheated methanol feedstock, and the vaporized methanol feedstock is then heated by the heater before entering the reactor, thus having the advantage of short start-up time. Furthermore, after the system starts up smoothly, the heater and low-pressure steam can be switched off, and the reaction products of the fluidized bed reactor can be fed into the methanol vaporizer and methanol superheater, thereby making full use of the heat of the reaction products. It also has the advantages of high heat utilization, low energy consumption, and low production cost.
[0023] 3. An external heat exchanger is installed on the outside of the fluidized bed reactor—since the production of dimethyl ether from methanol is an exothermic reaction, the external heat exchanger can remove the heat generated by the reaction, thereby ensuring that the reaction temperature is in an equilibrium state; an external heat exchanger is installed on the outside of the regenerator—since the coking and regeneration of the catalyst is an exothermic reaction, the external heat exchanger can remove the heat generated by the coking in the regenerator, thereby ensuring that the regenerator temperature is in an equilibrium state.
[0024] The external heat exchanger can be fluidized with low-pressure steam or nitrogen, while the external heat exchanger can be fluidized with factory air or nitrogen. The heat generated is steam. Both the external heat exchanger and the external heat exchanger can be fluidized in the upper and lower parts or in a back-mixing manner. The operation is flexible, the steam is produced as a by-product, the energy consumption is low, and the production cost is low.
[0025] 4. The fluidized bed reactor is equipped with a coarse vortex to separate the catalyst carried by the reaction products, and the regenerator is equipped with a regenerated coarse vortex to separate the catalyst carried by the flue gas. Together with the fine vortexes set at the gas outlet of both the fluidized bed reactor and the regenerator, namely the reaction fine vortex and the regenerated fine vortex, the coarse and fine vortexes are combined to effectively separate the carried catalyst by cyclone separation. The cyclone effect is obvious and it is environmentally friendly.
[0026] 5. The carbon carried by the coking catalyst in the regenerator is removed by compressed air. After the flue gas from coking and regeneration is passed through the regeneration fine cyclone to remove the fine catalyst powder it carries, it enters the waste heat recovery system to recover heat and produce steam as a by-product. This process results in low energy consumption and low production costs.
[0027] 6. The gas phase product, methanol, separated by the separator is sent back into the fluidized bed reactor for recycling, which can improve the product yield.
[0028] The present application will become more apparent by describing in following embodiments, in conjunction with the accompanying drawings, which serve to explain embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS
[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without any creative effort.
[0030] Figure 1 The present application is a structural schematic diagram.
[0031] 1-fluidized bed reactor; 2-regenerator; 3-methanol preheater; 4-methanol vaporizer; 5-methanol superheater; 6-reaction fine cyclone; 7-cooler; 8-separator; 9-product gas separation column; 10-regeneration fine cyclone; 11-reaction external heat exchanger; 12-regeneration external heat exchanger; 13-reaction coarse cyclone; 14-regeneration coarse cyclone; 15-heating furnace; 16-on-off valve A; 17-on-off valve B; 18-three-way switch valve. DETAILED DESCRIPTION
[0032] In order to make the purpose, technical scheme and advantages of the present application more clear, the following will further describe the present application in conjunction with the drawings. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the scope of protection of the present application.
[0033] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; of course, it can also be mechanical connection, or electrical connection; in addition, it can also be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.
[0034] The embodiments of the present application will now be described with reference to the accompanying drawings.
[0035] Embodiment:
[0036] The specific embodiments of this utility model are as follows: Figure 1 As shown, a process system for producing dimethyl ether includes a fluidized bed reactor 1 with a coarse reaction vortex 13 in its upper inner cavity. A methanol inlet pipe is connected to the lower side wall of the fluidized bed reactor 1, and a methanol preheater 3, a methanol vaporizer 4, and a methanol superheater 5 are sequentially arranged along the methanol flow direction on the methanol inlet pipe. A gas outlet pipe is connected to the top of the fluidized bed reactor 1, and a fine reaction vortex 6, a cooler 7, and a separator 8 are sequentially arranged along the gas flow direction on the gas outlet pipe. The separator 8 is connected to a product separation tower 9 via a liquid phase outlet pipe.
[0037] In operation, the system utilizes a methanol input pipeline to first feed methanol feedstock into methanol preheater 3, where hot water is used to preheat the feedstock. Then, the preheated methanol feedstock is vaporized in methanol vaporizer 4 and superheated in methanol superheater 5, becoming high-temperature methanol gas which then enters fluidized bed reactor 1 for reaction. Afterward, the reaction products from fluidized bed reactor 1 enter fine reaction vortex 6 via coarse vortex 13. After the catalyst carried by the reaction products is removed by the vortex, the reaction products are cooled by cooler 7 and then enter separator 8 for separation. Next, the gas phase separated by separator 8 is recycled back into fluidized bed reactor 1 for reprocessing, the water at the bottom of separator 8 is sent to a wastewater treatment system for recycling, and the liquid phase separated by separator 8 enters product gas separation tower 9. Finally, the product gas separated at the top of product gas separation tower 9 enters downstream for complete separation, and the heavy components at the bottom of product gas separation tower 9 are recycled.
[0038] The process system uses a fluidized bed reactor 1, which has the advantages of easy operation and high operational flexibility. The reaction of methanol dehydration to produce dimethyl ether is an exothermic reaction. Since the catalyst in the fluidized bed reactor 1 is fluidized, the heat transfer is relatively good, so it is not easy for hot spots to form in the catalyst bed, which will not lead to an increase in side reactions. This also improves the selectivity and yield of dimethyl ether and avoids the catalyst from aging and deactivating due to overheating.
[0039] Furthermore, a regenerator 2 is installed on one side of the fluidized bed reactor 1 to regenerate the deactivated catalyst in the fluidized bed reactor 1. Specifically, the fluidized bed reactor 1 is connected to the regenerator 2. The deactivated catalyst carrying coke after the reaction in the fluidized bed reactor 1 enters the regenerator 2 for coke burning and regeneration. The regeneration medium in the regenerator 2 is compressed air. The regenerated and reactivated catalyst re-enters the fluidized bed reactor 1, forming a two-stage catalyst fluidization, thereby extending the catalyst's service life.
[0040] In the system, the methanol vaporizer 4 and the methanol superheater 5 are both tube heat exchangers, the gas output pipeline between the reaction fine cyclone 6 and the cooler 7 passes through the heat exchange tubes of the methanol vaporizer 4 and the methanol superheater 5, and a switch valve A16 is arranged on the gas output pipeline between the methanol vaporizer 4 and the methanol superheater 5. Meanwhile, a low-pressure steam input pipeline is connected to the gas output pipeline between the switch valve A16 and the methanol vaporizer 4, and a switch valve B17 is arranged on the low-pressure steam input pipeline. In the embodiment, a heating furnace 15 is arranged on one side of the methanol superheater 5, the gas inlet end of the heating furnace 15 is connected to a three-way switch valve 18 arranged on the methanol input pipeline between the methanol vaporizer 4 and the methanol superheater 5 through a branch pipeline, and the gas outlet end of the heating furnace 15 is connected to the methanol input pipeline between the methanol superheater 5 and the fluidized bed reactor 1 through a branch pipeline.
[0041] The design is because, at the initial stage of starting up, the fluidized bed reactor 1 has not started the reaction yet / just started the reaction, the temperature is not high, and the reactant of the fluidized bed reactor 1 cannot provide sufficient heat exchange temperature for the methanol vaporizer 4 and the methanol superheater 5. Therefore, at the initial stage of starting up, the methanol vaporizer 4 uses low-pressure steam to vaporize the preheated methanol raw material, and the vaporized methanol raw material enters the fluidized bed reactor 1 after being heated by the heating furnace 15. Thus, the system has the advantage of short starting-up time. After the system is successfully started up, the heating furnace 15 and the low-pressure steam can be switched off, and the reaction product of the fluidized bed reactor 1 is introduced into the methanol vaporizer 4 and the methanol superheater 5, so that the heat of the reaction product is fully utilized, and the system has the advantages of high heat utilization, low energy consumption, and low production cost.
[0042] In the system, the fluidized bed reactor 1 is connected with a reaction external heat exchanger 11. Since the methanol production of dimethyl ether is an exothermic reaction, the reaction external heat exchanger 11 can take away the heat generated in the fluidized bed reactor 1, so as to ensure that the temperature of the fluidized bed reactor 1 is in a balanced state. The fluidization of the reaction external heat exchanger 11 can use low-low-pressure steam or nitrogen, and the heat steam taken away can use the up-and-down fluidization or back-mixing form. In the embodiment, a reaction coarse cyclone 13 is arranged in the fluidized bed reactor 1, and the reaction coarse cyclone 13 uses a plurality of sets of primary and secondary cyclone separators to separate the catalyst carried by the reaction product, and the cyclone effect is obvious.
[0043] Meanwhile, the regenerator 2 is externally connected with a regeneration external heat exchanger 12. Since the carbon of the coked regeneration catalyst belongs to an exothermic reaction, the regeneration external heat exchanger 12 takes away the heat generated by the coking of the regenerator 2, so as to ensure that the temperature of the regenerator 2 is in a balanced state. The fluidization of the regeneration external heat exchanger 12 can adopt factory air or nitrogen fluidization, and the steam taken away by the regeneration external heat exchanger 12 can adopt up-and-down fluidization or back-mixing form. In the embodiment, the regenerator 2 is provided with a regeneration coarse cyclone 14 in the inner cavity of the upper portion, and the regeneration coarse cyclone 14 adopts a two-stage cyclone separator with multiple groups, which separates the catalyst carried by the flue gas, and the cyclone effect is obvious.
[0044] In addition, the regenerator 2 is connected with a regeneration fine cyclone 10 through a pipeline at the top. The regenerator 2 adopts compressed air, and the carbon carried by the coked catalyst is burned. After the flue gas after the coking regeneration passes through the regeneration fine cyclone 10 and the catalyst fine powder carried by the flue gas is separated by cyclone, the flue gas enters a waste heat recovery system to recover heat and produce steam, so as to reduce the energy consumption and production cost.
[0045] In the embodiment, the separator 8 is connected with a methanol input pipeline arranged between the methanol superheater 5 and the fluidized bed reactor 1 through a gas phase output pipe. The gas phase separated by the separator 8 from the top is methanol, which is sent to the fluidized bed reactor 1 for reprocessing, so as to improve the product yield.
[0046] The utility model has been described above in combination with the best embodiment, but the utility model is not limited to the above disclosed embodiments, and should cover various modifications, equivalent combinations and the like according to the essence of the utility model.
Claims
1. A process system for producing dimethyl ether, characterized by, The fluidized bed reactor (1) is provided with a reaction coarse cyclone (13) in the upper inner cavity, a methanol input pipeline is connected to the lower side wall of the fluidized bed reactor (1), and a methanol preheater (3), a methanol vaporizer (4) and a methanol superheater (5) are sequentially arranged on the methanol input pipeline along the methanol flow direction. A gas output pipeline is connected to the top of the fluidized bed reactor (1), and a reaction fine cyclone (6), a cooler (7) and a separator (8) are sequentially arranged on the gas output pipeline along the gas flow direction, and the separator (8) is connected to a product separation tower (9) through a liquid phase output pipeline. A regenerator (2) for regenerating the deactivated catalyst in the fluidized bed reactor (1) is further arranged on one side of the fluidized bed reactor (1).
2. The process system for producing dimethyl ether according to claim 1, characterized by, The methanol vaporizer (4) and the methanol superheater (5) are both pipe heat exchangers, the gas output pipeline between the reaction fine cyclone (6) and the cooler (7) passes through the heat exchange pipes of the methanol vaporizer (4) and the methanol superheater (5), and a switch valve A (16) is further arranged on the gas output pipeline between the methanol vaporizer (4) and the methanol superheater (5).
3. The process system for producing dimethyl ether according to claim 2, characterized by, A low-pressure steam input pipe is further communicated with the gas output pipeline between the switch valve A (16) and the methanol vaporizer (4), and a switch valve B (17) is arranged on the low-pressure steam input pipe.
4. The process system for producing dimethyl ether according to claim 2 or 3, characterized by, A heating furnace (15) is further arranged on one side of the methanol superheater (5), the gas inlet end of the heating furnace (15) is connected to a three-way switch valve (18) arranged on the methanol input pipeline between the methanol vaporizer (4) and the methanol superheater (5) through a branch pipeline, and the gas outlet end of the heating furnace (15) is connected to the methanol input pipeline between the methanol superheater (5) and the fluidized bed reactor (1) through a branch pipeline.
5. The process system for producing dimethyl ether according to claim 1, wherein, A reaction external heat exchanger (11) is connected to the outside of the fluidized bed reactor (1).
6. The process system for producing dimethyl ether according to claim 1, wherein, The reaction coarse cyclone (13) adopts a two-stage cyclone separator arranged in multiple groups.
7. The process system for producing dimethyl ether according to claim 1, wherein, A regeneration external heat exchanger (12) is connected to the outside of the regenerator (2).
8. The process system for producing dimethyl ether according to claim 1 or 7, characterized by, A regeneration coarse cyclone (14) is arranged in the upper inner cavity of the regenerator (2), and the regeneration coarse cyclone (14) adopts a two-stage cyclone separator arranged in multiple groups.
9. The process system for producing dimethyl ether according to claim 8, characterized by, A regeneration fine cyclone (10) is connected to the top of the regenerator (2) through a pipeline.
10. The process system for producing dimethyl ether according to claim 1, characterized by, The separator (8) is connected to the methanol input pipeline between the methanol superheater (5) and the fluidized bed reactor (1) through a gas phase output pipeline.