Method for continuously synthesizing dimethyl sulfate

Abstract

The invention provides a method for continuously synthesizing dimethyl sulfate, which uses the reaction system provided by the invention to continuously synthesize dimethyl sulfate, and comprises the following steps: simultaneously and respectively dissolving and absorbing SO3 and dimethyl ether in crude dimethyl sulfate stored in a primary absorption circulating tank and a primary reaction circulating tank to form two absorption liquids; the method comprises the following steps: respectively absorbing an absorption liquid 1 for absorbing dimethyl ether and an absorption liquid 2 for absorbing SO3, then conveying the absorption liquid 2 into a primary reaction circulating tank for storing the absorption liquid 1, carrying out esterification reaction to generate dimethyl sulfate, and sequentially conveying materials which are not completely reacted into a secondary reaction circulating tank and a secondary absorption circulating tank for continuous reaction. The method is simple in process, energy consumption is reduced, cost is saved, the production problems of running, overflowing, dripping, leaking and the like are completely eradicated through the continuous production technology, and a guarantee is provided for large-scale industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of chemical preparation technology, and in particular to a method for continuously synthesizing dimethyl sulfate. Background Art

[0002] Dimethyl sulfate is an important chemical intermediate and methylating agent, which is widely used in many industries such as medicine, agriculture, textile, construction, petrochemical, papermaking, food, and daily chemical production. As for the synthesis method of dimethyl sulfate, the most common one is to use sulfur trioxide (SO3) and dimethyl ether (DME) to undergo esterification reaction to obtain dimethyl sulfate.

[0003] Patent document CN109748827A discloses a process for the continuous synthesis of dimethyl sulfate, in which sulfur trioxide and dimethyl ether are successively absorbed by crude dimethyl sulfate in different sections of a three-stage esterification reaction tower, contacted and reacted to generate dimethyl sulfate, and then degassed and distilled to obtain the dimethyl sulfate product and the by-product methyl hydrogen sulfate.

[0004] Patent document CN1086209A discloses a method and equipment for preparing sulfate ester by burning sulfur in dry air, which is characterized by comprising a fan, a refrigeration-zeolite adsorption, a sulfur burning furnace, a conversion tower, an absorption tower, an etherification tank, an esterification tank, etc. Precooled dry air reacts with burning sulfur to produce dry sulfur dioxide gas, which is then converted into 9-11% sulfur trioxide gas, dimethyl sulfate is used as an absorption solvent, and then esterified with dimethyl ether to produce dimethyl sulfate.

[0005] Patent document CN103570590A discloses an apparatus for generating dimethyl sulfate, comprising an esterification reaction tower, a degassing tower and a distillation tower, wherein a top feed port at the top of the esterification reaction tower is connected to a liquid material source through a pipeline, an esterification reaction tower material outlet at the bottom of the esterification reaction tower is connected to a degassing tower feed port in the middle of the degassing tower through a pipeline, a top discharge port at the top of the distillation tower is connected to an external first storage tank through a pipeline, a side discharge port at the middle and upper part of the distillation tower is connected to an external second storage tank through a pipeline, and a degassing tower gas outlet at the top of the degassing tower is connected to an absorption tower gas inlet of an absorption tower through a pipeline.

[0006] Patent document CN109748827A discloses a process and equipment for continuously synthesizing dimethyl sulfate. The two raw materials, sulfur trioxide and dimethyl ether, are successively absorbed by crude dimethyl sulfate in different sections of a three-stage esterification reaction tower, contacted and reacted to generate dimethyl sulfate, and then degassed and distilled to obtain dimethyl sulfate products and byproduct methyl hydrogen sulfate, including a continuous synthesis reaction process and a degassing and distillation process: the continuous synthesis reaction process occurs in a three-stage esterification reaction tower, and the reaction tower is divided into three sections: a SO3 absorption section, a dimethyl ether DME absorption esterification section, and an aging section. The dimethyl ether DME absorption esterification section and the aging section of the three-stage esterification reaction tower are internally provided with a plurality of tower-level components, which are distributed on the inner wall of the tower body in the section, and the tower-level components are in a fan-shaped structure.

[0007] However, the above-mentioned prior art generally has the following defects: (1) The reactions of sulfur trioxide, dimethyl ether and dimethyl sulfate are all carried out in one reactor, and the controllability of the reaction is poor, which can easily cause violent reactions, overheating, and excessive reaction speed, resulting in side reactions and a large number of impurities; (2) Dimethyl ether is a flammable gas and sulfur trioxide is a strong oxidant. When both are dissolved in dimethyl sulfate at the same time for esterification reaction, local overheating may cause an explosive reaction and cause a safety accident; (3) The reaction of sulfur trioxide and dimethyl ether is incomplete and the utilization rate is low. Summary of the invention

[0008] In order to overcome the disadvantages of the above-mentioned prior art, the present invention provides a method for continuously synthesizing dimethyl sulfate, which can continuously produce, make the esterification reaction fully uniform, have a fast reaction speed, high production efficiency, high output, high purity of the produced product, save energy and reduce consumption, reduce the acidity of the product, and produce dimethyl sulfate safely and environmentally friendly.

[0009] In a first aspect of the present invention, a reaction system for continuously synthesizing dimethyl sulfate is provided, comprising an absorption module 1, an absorption module 2, a reaction module 1 and a reaction module 2;

[0010] The absorption module 1 and the absorption module 2 respectively include an absorption tower (e.g., a primary absorption tower, a secondary absorption tower), a circulation tank (e.g., a primary absorption circulation tank, a secondary absorption circulation tank), a circulation pump (e.g., a primary absorption circulation pump, a secondary absorption circulation pump) and a cooler (e.g., a primary absorption cooler, a secondary absorption cooler), and the absorption tower, the circulation tank, the circulation pump and the cooler in each absorption module are connected in sequence to form a cycle; the reaction module 1 and the reaction module 2 respectively include a reaction tower (e.g., a primary reaction tower, a secondary reaction tower), a circulation tank (e.g., a primary reaction circulation tank, a secondary reaction circulation tank), a circulation pump (e.g., a primary reaction circulation pump, a secondary reaction circulation pump) and a cooler (e.g., a primary reaction cooler, a secondary reaction cooler), and the reaction tower, the circulation tank, the circulation pump and the cooler in each reaction module are connected in sequence to form a cycle;

[0011] The absorption module 1 is connected to the reaction module 1, the reaction module 1 is connected to the reaction module 2, and the reaction module 2 is connected to the absorption module 2;

[0012] Sulfur trioxide is fed from the absorption module 1, and dimethyl ether is fed from the reaction module 1.

[0013] Furthermore, dimethyl ether can also be fed from the reaction module 2 and / or the absorption module 2.

[0014] Furthermore, crude dimethyl sulfate can be fed from the absorption module one, the absorption module two, the reaction module one and the reaction module two.

[0015] Furthermore, the reaction system also includes a pipeline module.

[0016] Furthermore, the pipeline module includes a sulfur trioxide feed pipeline, a dimethyl ether feed pipeline, a crude dimethyl sulfate feed pipeline, a tail gas delivery line and a product delivery pipeline.

[0017] Furthermore, the sulfur trioxide feed pipeline is connected to the absorption tower in absorption module one; the dimethyl ether feed pipeline is connected to the circulation tanks of absorption module two, reaction module one and reaction module two respectively; the crude dimethyl sulfate feed pipeline is connected to the circulation tanks of absorption module one, absorption module two, reaction module one and reaction module two respectively; the tail gas delivery pipeline is connected to the absorption tower of absorption module two; the product delivery pipeline is connected to the circulation tank of reaction module one.

[0018] Furthermore, in the absorption module 1, the bottom of the absorption tower is connected to the top of the circulation tank, the circulation pump is connected to the bottom of the condenser, and the top of the condenser is connected to the upper part of the absorption tower.

[0019] Furthermore, in the absorption module 2, the bottom of the absorption tower is connected to the top of the circulation tank, the circulation pump is connected to the bottom of the condenser, and the top of the condenser is connected to the upper part of the absorption tower.

[0020] Furthermore, in the reaction module 1, the bottom of the reaction tower is connected to the top of the circulation tank, the circulation pump is connected to the bottom of the condenser, and the top of the condenser is connected to the upper part of the absorption tower.

[0021] Furthermore, in the reaction module 2, the bottom of the reaction tower is connected to the top of the circulation tank, the circulation pump is connected to the bottom of the condenser, and the top of the condenser is connected to the upper part of the absorption tower.

[0022] Furthermore, the absorption tower of the absorption module 1 can be connected to the absorption tower of the absorption module 2, and can be used to receive the incompletely absorbed sulfur trioxide;

[0023] Furthermore, the reaction tower of the reaction module 1 may be connected to the reaction tower of the reaction module 2, and may be used to receive dimethyl ether or sulfur trioxide that is not completely absorbed and / or reacted;

[0024] Furthermore, the reaction tower of the reaction module 2 may be connected to the absorption tower of the absorption module 2, and may be used to receive dimethyl ether or sulfur trioxide that is not completely absorbed and / or reacted.

[0025] Furthermore, the circulation tank of the absorption module one is also connected to the absorption module two, the reaction module one and the reaction module two respectively;

[0026] Furthermore, the circulation tank of the absorption module 2 is also connected to the absorption module 1, the reaction module 1 and the reaction module 2 respectively;

[0027] Furthermore, the circulation tank of the reaction module 1 is also connected to the absorption module 1, the absorption module 2 and the reaction module 2 respectively;

[0028] Furthermore, the circulation tank of the reaction module 2 is also connected to the absorption module 1, the absorption module 2 and the reaction module 1 respectively.

[0029] Furthermore, the sulfur trioxide feed pipeline is connected to the middle part of the absorption tower in the absorption module one.

[0030] Furthermore, the dimethyl ether feed pipeline is respectively connected to the absorption module 2, the reaction module 1 and one side of the top of the circulation tank of the reaction module 2.

[0031] Furthermore, the tail gas delivery pipeline is connected to the top of the absorption tower of the absorption module two.

[0032] Furthermore, the circulation tank can be combined with the absorption tower or the reaction tower to form an integrated reactor.

[0033] Furthermore, the reaction system also includes a product tank and a tail gas treatment device; the product tank is connected to the product delivery pipeline; the tail gas treatment device is connected to the tail gas delivery pipeline.

[0034] Furthermore, the absorption tower and the reaction tower are both packed towers.

[0035] Furthermore, the packing of the packed tower is ceramic corrugated packing or saddle-shaped ceramic packing.

[0036] Furthermore, the sulfur trioxide is prepared by a pyrite acid production process.

[0037] Furthermore, the substance transported by the sulfur trioxide feed pipeline is sulfur trioxide.

[0038] Furthermore, the substance transported by the dimethyl ether feed pipeline is dimethyl ether.

[0039] Furthermore, the substance transported by the crude dimethyl sulfate feed pipeline is crude dimethyl sulfate.

[0040] Furthermore, the tail gas delivery pipeline is used to deliver the tail gas generated by the reaction.

[0041] Furthermore, the product delivery pipeline is used to deliver the product dimethyl sulfate.

[0042] The second aspect of the present invention provides a method for continuously synthesizing dimethyl sulfate, which uses the reaction system described in the first aspect to continuously synthesize dimethyl sulfate, including dissolving and absorbing SO3 and dimethyl ether in crude dimethyl sulfate stored in a primary absorption circulation tank and a primary reaction circulation tank, respectively, to form two absorption liquids, namely, absorption liquid 1 for absorbing dimethyl ether and absorption liquid 2 for absorbing SO3, and then transporting absorption liquid 2 to the primary reaction circulation tank storing absorption liquid 1 for esterification reaction to generate dimethyl sulfate, and the incompletely reacted materials are sequentially transported to the secondary reaction circulation tank and the secondary absorption circulation tank for continued reaction.

[0043] Furthermore, the method comprises the following steps: crude dimethyl sulfate is transported to the circulation tanks of absorption module 1, absorption module 2, reaction module 1, and reaction module 2 until the liquid level reaches 20-40% (e.g., 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40%) of the height of the circulation tank; after dimethyl ether is transported to the circulation tank of reaction module 1, it is dissolved in crude dimethyl sulfate. After decomposition and absorption, absorption liquid 1 is obtained. Meanwhile, after SO3 is transported to the absorption tower of absorption module one, it is dissolved and absorbed by crude dimethyl sulfate to obtain absorption liquid 2. Absorption liquid 2 enters reaction module one, mixes with absorption liquid 1, undergoes esterification reaction and generates dimethyl sulfate. The material that has not been completely reacted in reaction module one enters reaction module two to continue to undergo esterification reaction and generate dimethyl sulfate, and the material that has not been completely reacted in reaction module two enters absorption module two to continue to undergo esterification reaction and generate dimethyl sulfate.

[0044] Furthermore, the tail gas generated in the method is transported to the tail gas treatment device through a tail gas transport pipeline.

[0045] Furthermore, the tail gas includes: SO3 content 0.01-0.03%, SO2 content 0.3-0.5%, oxygen 3-5%, trace amounts of dimethyl sulfate and dimethyl ether, and the rest is nitrogen.

[0046] Furthermore, as the production process continues, the liquid levels in the circulation tanks of absorption module one, absorption module two, reaction module one, and reaction module two continue to rise. When the liquid level rises to 60-80% (such as 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80%) of the height of the circulation tank, the dimethyl ether switching pipeline is transported to the circulation tank of reaction module two, and the dimethyl sulfate generated in absorption module one, absorption module two, and reaction module two is transported to the circulation tank of reaction module one.

[0047] Furthermore, when the purity of dimethyl sulfate in the circulation tank of the reaction module 1 is ≥99%, it is transported to the product tank.

[0048] Furthermore, in the process of dimethyl sulfate being transported to the product tank, the liquid level of the circulation tank of absorption module one, absorption module two, reaction module one, and reaction module two continues to decrease. When the liquid level of the circulation tank of absorption module one, absorption module two, reaction module one, and reaction module two drops to 20-40% (such as 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40%) of the height of the circulation tank, the dimethyl ether switching pipeline is transported to the circulation tank of reaction module one to continue production.

[0049] Furthermore, the acidity of the absorption module 1, the absorption module 2, the reaction module 1, and the reaction module 2 can be controlled by adjusting the intake amount of dimethyl ether or SO3.

[0050] Furthermore, the purity of the dimethyl sulfate obtained by the method is ≥99%.

[0051] The reaction system for continuously synthesizing dimethyl sulfate of the present invention comprises a multi-stage absorption reactor, which solves the problem of poor controllability of the reaction. Dimethyl ether and sulfur trioxide are successively dissolved and absorbed by crude dimethyl sulfate in multiple absorption reactors, respectively, thereby improving the utilization rate of dimethyl ether and sulfur trioxide, and effectively preventing direct contact between dimethyl ether and sulfur trioxide, thereby improving the adequacy and safety of the esterification reaction. The method for continuously synthesizing dimethyl sulfate of the present invention has a simple process, reduces energy consumption, saves costs, and the continuous production process eliminates the occurrence of production problems such as running, bubbling, dripping, and leaking, and also provides a guarantee for realizing large-scale industrial production. The purity of the obtained dimethyl sulfate product is ≥99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Shown is a schematic diagram of the reaction system structure.

[0053] Among them, 100-absorption module one, 200-absorption module two, 300-reaction module two, 400-reaction module one; 101-primary absorption tower, 102-primary absorption circulation tank, 103-primary absorption circulation pump, 104-primary absorption condenser; 201-secondary absorption tower, 202-secondary absorption circulation tank, 203-secondary absorption circulation pump, 204-secondary absorption condenser; 301-secondary reaction tower, 302-secondary reaction circulation tank, 303-secondary reaction circulation pump, 304-secondary reaction condenser; 401-primary reaction tower, 402-primary reaction circulation tank, 403-primary reaction circulation pump, 404-primary reaction condenser; 501-sulfur trioxide feed pipeline, 502-dimethyl ether feed pipeline, 503-crude dimethyl sulfate feed pipeline, 504-tail gas delivery line, 505-product delivery pipeline.

[0054] →Indicates that all route pipelines are displayed; Indicates a pipeline whose entire route is not displayed (taking 100 as an example, it indicates that the pipeline is connected to 201, 301, and 401). DETAILED DESCRIPTION

[0055] Unless otherwise defined, all scientific and technical terms used in the present invention have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention relates.

[0056]

[00136] Various publications, patents, and published patent specifications are cited herein, the disclosures of which are incorporated by reference in their entireties.

[0057] The technical solution of the present invention will be clearly and completely described below in conjunction with 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 are within the scope of protection of the present invention.

[0058] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0059] Example 1

[0060] like Figure 1As shown, the reaction system for continuously synthesizing dimethyl sulfate includes an absorption module 100, an absorption module 200, a reaction module 300, a reaction module 400 and a pipeline module, wherein the absorption module 100 includes a primary absorption tower 101, a primary absorption circulation tank 102, a primary absorption circulation pump 103 and a primary absorption condenser 104, and the absorption module 200 includes a secondary absorption tower 201, a secondary absorption circulation tank 202, a secondary absorption circulation pump 203 and a secondary absorption condenser 204. 4, reaction module 2 300 includes a secondary reaction tower 301, a secondary reaction circulation tank 302, a secondary reaction circulation pump 303 and a secondary reaction condenser 304, reaction module 1 400 includes a primary reaction tower 401, a primary reaction circulation tank 402, a primary reaction circulation pump 403 and a primary reaction condenser 404, and the pipeline module includes a sulfur trioxide feed pipeline 501, a dimethyl ether feed pipeline 502, a crude dimethyl sulfate feed pipeline 503, an exhaust gas delivery pipeline 504, and a product delivery pipeline 505. The packing of the primary absorption tower 101 is a ceramic corrugated packing, and the packing of the secondary absorption tower 201, the secondary reaction tower 301 and the primary reaction tower 401 is a saddle-shaped ceramic packing.

[0061] In the absorption module 100, the bottom of the primary absorption tower 101 is connected to the top of the primary absorption circulation tank 102, one side of the primary absorption circulation tank 102 is connected to the primary absorption circulation pump 103, the primary absorption circulation pump 103 is connected to the bottom of the primary absorption condenser 104, and the top of the primary absorption condenser 104 is connected to the upper part of the primary absorption tower 101, thereby, the primary absorption tower 101, the primary absorption circulation tank 102, the primary absorption circulation pump 103 and the primary absorption condenser 104 are connected in sequence to form a circulation.

[0062] The connection method of the absorption tower (201) or reaction tower (301, 401), circulation tank (202, 302, 402), circulation pump (203, 303, 403) and condenser (204, 304, 404) in the absorption module 2 200, the reaction module 2 300 and the reaction module 1 400 is the same as that of the above-mentioned absorption module 100.

[0063] The top side of the primary absorption circulation tank 102 is connected to the secondary absorption tower 201, the secondary reaction tower 301 and the primary reaction tower 401 respectively, the top side of the secondary absorption circulation tank 202 is connected to the primary absorption tower 101, the secondary reaction tower 301 and the primary reaction tower 401 respectively, the top side of the secondary reaction circulation tank 302 is connected to the primary absorption tower 101, the secondary absorption tower 201 and the primary reaction tower 401 respectively, and the top side of the primary reaction circulation tank 402 is connected to the primary absorption tower 101, the secondary absorption tower 201 and the secondary reaction tower 301 respectively.

[0064] The top of the primary absorption tower 101 is connected to the middle of the secondary absorption tower 201 , the top of the primary reaction tower 401 is connected to the middle of the secondary reaction tower 301 , and the top of the secondary reaction tower 301 is connected to the middle of the secondary absorption tower 201 .

[0065] The sulfur trioxide feed line 501 is connected to the middle of the primary absorption tower 101, and the dimethyl ether feed line 102 is respectively connected to the secondary absorption circulation tank 202, the secondary reaction circulation tank 302 and the top side of the primary reaction circulation tank 402. The crude dimethyl sulfate feed line 503 is respectively connected to the primary absorption circulation tank 102, the secondary absorption circulation tank 202, the secondary reaction circulation tank 302 and the primary reaction circulation tank 402. The tail gas delivery line 504 is connected to the top of the secondary absorption tower 201. The product delivery line 505 is connected to the primary reaction circulation tank 402.

[0066] The reaction system further includes a product tank and a tail gas treatment device. The product tank is connected to the product delivery pipeline 505 , and the tail gas treatment device is connected to the tail gas delivery pipeline 504 .

[0067] Example 2

[0068] The process of continuously synthesizing dimethyl sulfate using the reaction system is as follows:

[0069] The crude dimethyl sulfate is transported to the circulation tanks (102, 202, 302, 402) of the four modules until the liquid level reaches 20-40% of the height of the circulation tank. After dimethyl ether is transported to the primary reaction circulation tank 402, it is dissolved and absorbed by the crude dimethyl sulfate to obtain absorption liquid 1; at the same time, after SO3 is transported to the primary absorption tower 101, it is dissolved and absorbed by the crude dimethyl sulfate to obtain absorption liquid 2. The cooling water circulation system (104, 204, 304, 404) is turned on, and the temperature of the reaction module 1 and the reaction module 2 is controlled within the temperature range suitable for the reaction of sulfur trioxide and dimethyl ether. The absorption liquid 2 enters the reaction module 1 400, mixes with the absorption liquid 1, undergoes an esterification reaction and generates dimethyl sulfate. The unreacted materials in reaction module one 400 enter reaction module two 300 to continue reaction, and the unreacted materials in reaction module two 300 enter absorption module two 200 to continue reaction. The tail gas (SO3 content 0.01-0.03%, SO2 content 0.3-0.5%, oxygen 3-5%, trace amounts of dimethyl sulfate and dimethyl ether, and the rest is nitrogen) is transported to the tail gas treatment device through the tail gas delivery pipeline 504.

[0070] As the production process continues, the liquid levels of the circulation tanks (102, 202, 302, 402) of the four modules continue to rise. When the liquid level rises to 60-80% of the height of the circulation tank, the dimethyl ether is switched to the secondary reaction circulation tank 302, and the dimethyl sulfate generated in the absorption module 100, the absorption module 200, and the reaction module 2 300 is transported to the primary reaction circulation tank 402. After the sampling and analysis are qualified, the dimethyl sulfate product (purity ≥ 99%) is transported to the product tank through the product delivery pipeline 505. At the same time, the liquid levels of the circulation tanks (102, 202, 302, 402) of the four modules continue to decrease. When the liquid levels of the circulation tanks (102, 202, 302, 402) of the four modules drop to 20-40% of the height of the circulation tank, the dimethyl ether is switched to the primary reaction circulation tank 402, and the production continues smoothly.

[0071] During the production process, samples are taken and analyzed regularly, and the intake volume of dimethyl ether is adjusted according to the acidity results to maintain stable system acidity.

[0072] In the above production process, the utilization rate of the two gases is improved, the raw material consumption and production costs are greatly reduced, the reaction is mild and controllable, there is no overheating or excessive reaction speed, few by-products and impurities are generated, and the tail gas does not require further treatment, which greatly reduces waste emissions in the production process and its treatment costs, and the process is more environmentally friendly and safe.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0074] The aforementioned embodiments and methods described in the present invention may be varied based on the ability, experience and preference of those skilled in the art.

[0075] In the present invention, merely listing the steps of the method in a certain order does not constitute any limitation on the order of the method steps.

Claims

1. A method for continuously synthesizing dimethyl sulfate, which uses a reaction system for continuously synthesizing dimethyl sulfate to continuously synthesize dimethyl sulfate, wherein the reaction system comprises an absorption module 1 (100), an absorption module 2 (200), a reaction module 2 (300) and a reaction module 1 (400), characterized in that: The absorption module 1 (100) and the absorption module 2 (200) respectively include an absorption tower (101, 201), a circulation tank (102, 202), a circulation pump (103, 203) and a cooler (104, 204); the absorption tower (101, 201), the circulation tank (102, 202), the circulation pump (103, 203) and the cooler (104, 204) in each absorption module are sequentially connected to form a cycle; the reaction module 2 (300) and the reaction module 1 (400) respectively include a reaction tower (301, 401), a circulation tank (302, 402), a circulation pump (303, 403) and a cooler (304, 404); the reaction tower (301, 401), the circulation tank (302, 402), the circulation pump (303, 403) and the cooler (304, 404) in each reaction module are sequentially connected to form a cycle; The absorption module 1 (100) is connected to the reaction module 1 (400), the reaction module 1 (400) is connected to the reaction module 2 (300), and the reaction module 2 (300) is connected to the absorption module 2 (200); Sulfur trioxide is fed from the absorption module one (100), and dimethyl ether is fed from the reaction module one (400); Preferably, dimethyl ether is also fed from the reaction module 2 (300) and / or the absorption module 2 (200); The method comprises dissolving and absorbing SO3 and dimethyl ether in crude dimethyl sulfate stored in a circulation tank (102) and a circulation tank (402) respectively, to form two absorption liquids, namely, absorption liquid 1 for absorbing dimethyl ether and absorption liquid 2 for absorbing SO3; then, the absorption liquid 2 is transported to the circulation tank (402) storing the absorption liquid 1 to undergo an esterification reaction to generate dimethyl sulfate; and the incompletely reacted materials are transported to the circulation tank (302) and the circulation tank (202) in sequence to continue the reaction.

2. The method according to claim 1, characterized in that The bottom of the absorption tower (101) is connected to the top of the circulation tank (102), the circulation pump (103) is connected to the bottom of the condenser (104), and the top of the condenser (104) is connected to the upper part of the absorption tower (101); and / or, The bottom of the absorption tower (201) is connected to the top of the circulation tank (202), the circulation pump (203) is connected to the bottom of the condenser (204), and the top of the condenser (204) is connected to the upper part of the absorption tower (201); and / or, The bottom of the reaction tower (301) is connected to the top of the circulation tank (302), the circulation pump (303) is connected to the bottom of the condenser (304), and the top of the condenser (304) is connected to the upper part of the absorption tower (301); and / or, The bottom of the reaction tower (401) is connected to the top of the circulation tank (402), the circulation pump (403) is connected to the bottom of the condenser (404), and the top of the condenser (404) is connected to the upper part of the absorption tower (401).

3. The method according to claim 1, characterized in that The reaction tower (401) is connected to the reaction tower (301); and / or, The reaction tower (301) is connected to the absorption tower (201); and / or, The circulation tank (102) is also connected to the absorption module 2 (200), the reaction module 1 (400) and the reaction module 2 (300) respectively; and / or, The circulation tank (202) is also connected to the absorption module 1 (100), the reaction module 1 (400) and the reaction module 2 (300) respectively; and / or, The circulation tank (302) is also connected to the absorption module 1 (100), the absorption module 2 (200) and the reaction module 1 (400) respectively; and / or, The circulation tank (402) is also connected to the absorption module one (100), the absorption module two (200) and the reaction module two (300) respectively.

4. The method according to claim 1, characterized in that: The reaction system further comprises a pipeline module, wherein the pipeline module comprises a sulfur trioxide feed pipeline (501), a dimethyl ether feed pipeline (502), a crude dimethyl sulfate feed pipeline (503), a tail gas delivery pipeline (504) and a product delivery pipeline (505).

5. The method according to claim 4, characterized in that The sulfur trioxide feed pipeline (501) is connected to the absorption tower (101); The dimethyl ether feed pipeline (502) is in communication with the circulation tank (402), and the dimethyl ether feed pipeline (502) is also in communication with the circulation tank (202) and / or the circulation tank (302); The crude dimethyl sulfate feed pipeline (503) is respectively connected to the circulation tank (102), the circulation tank (202), the circulation tank (302) and the circulation tank (402); The tail gas delivery pipeline (504) is in communication with the absorption tower (201); The product delivery pipeline (505) is in communication with the circulation tank (402).

6. The method according to claim 5, characterized in that The reaction system also includes a product tank and a tail gas treatment device; Preferably, the product delivery pipeline (505) is connected to a product tank; and / or, The tail gas delivery pipeline (504) is in communication with the tail gas treatment device, and the generated tail gas is delivered to the tail gas treatment device through the tail gas delivery pipeline (504).

7. The method according to claim 1, characterized in that The absorption tower (101), the absorption tower (201), the reaction tower (301) and the reaction tower (401) are all packed towers; Preferably, the packing of the packed tower is ceramic corrugated packing or saddle-shaped ceramic packing.

8. The method according to claim 1, characterized in that As the production process continues, the liquid level of the circulation tank (102, 202, 302, 402) continues to rise. When the liquid level rises to 60-80% of the height of the circulation tank (102, 202, 302, 402), the dimethyl ether switching pipeline is transported to the circulation tank (302), and at the same time, the dimethyl sulfate generated in the absorption module one (100), the absorption module two (200), and the reaction module two (300) is transported to the circulation tank (402).

9. The method according to claim 8, characterized in that When the purity of dimethyl sulfate in the circulation tank (402) is ≥99%, it is transported to the product tank.

10. The method according to claim 9, characterized in that During the process of dimethyl sulfate being transported to the product tank, the liquid level of the circulation tank (102, 202, 302, 402) continues to decrease. When the liquid level of the circulation tank (102, 202, 302, 402) decreases to 20-40% of the height of the circulation tank (102, 202, 302, 402), the dimethyl ether switching pipeline is transported to the circulation tank (402) to continue production.

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