A device and method for producing chloromethane using ammonium chloride and hydrogen chloride as chlorine sources

Abstract

The application belongs to the technical field of chemical industry, and provides a device and method for synthesizing chloromethane and ammonia by using ammonium chloride, hydrogen chloride and methanol. The ammonium chloride decomposition reaction process and the chloromethane synthesis reaction process are respectively carried out in two reactors, so that the problem of catalyst deactivation caused by deposition and blockage of salt impurities such as sodium chloride and sodium bicarbonate in the ammonium chloride can be effectively avoided. The three sets of tubular ammonium chloride feeding devices provided by the application can keep the ammonium chloride in a low-temperature and loose state during the feeding process, and effectively avoid the problem of ammonium chloride feeding pipe blockage.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically relating to a method and apparatus for synthesizing chloromethane using ammonium chloride and hydrogen chloride. Background Technology

[0002] Soda ash is an important chemical raw material, and China's soda ash industry has developed rapidly, with the combined soda ash industry being the most prominent. This rapid development has resulted in a large amount of ammonium chloride as a byproduct. Due to its high chlorine content, ammonium chloride has extremely limited use in agriculture; its application in industry and pharmaceuticals is also very limited. Excessive ammonium chloride inventory has severely restricted the development of the soda ash industry, making the comprehensive utilization of ammonium chloride extremely important.

[0003] The reaction of methanol with ammonium chloride yields chloromethane and allows for the recovery of ammonia. Chloromethane is an important raw material for the synthesis of methylchlorosilanes, methylcellulose, quaternary ammonium salts, and other products, and is widely used in pesticides, synthetic resins, and additives. Ammonia is an important chemical raw material that can be recycled in the soda ash industry and used in other sectors. Therefore, the process of synthesizing chloromethane from ammonium chloride and methanol can solve the problem of large amounts of surplus ammonium chloride and produce high-value-added chloromethane, thus achieving the recovery and utilization of both chlorine and ammonia.

[0004] US patents US2755311, US2755316, and US3315441 propose methods for preparing chloromethane and ammonia from ammonium chloride and methanol, involving two process flows: One involves passing gaseous ammonium chloride and methanol vapor into a fixed bed containing alumina particles for reaction. Besides chloromethane, small amounts of methylamine and dimethyl ether are produced as byproducts, which can be recycled and reacted back into chloromethane. The other method involves mixing solid ammonium chloride with a molten catalyst, then reacting it with methanol. After the reaction, the catalyst is separated and recycled; the catalyst is cuprous chloride. However, due to the poor thermal conductivity of solid ammonium chloride, its surface shrinks upon heating and it is prone to agglomeration, making direct vaporization challenging.

[0005] Chinese Patent 201410008694.3 describes a method that mixes ammonium chloride and concentrated phosphoric acid and pumps the mixture into a tubular reactor to produce diammonium hydrogen phosphate and hydrogen chloride gas. The hydrogen chloride gas is used to synthesize chloromethane. The diammonium hydrogen phosphate is heated and decomposed to produce ammonia and a mixture of phosphoric acid and metaphosphoric acid. The phosphoric acid and metaphosphoric acid are recycled, and the ammonia is compressed and condensed to obtain liquid ammonia. However, this method suffers from drawbacks such as a long process flow and high energy consumption. Chinese Patent CN201110388852.9 discloses a method that couples the decomposition of ammonium chloride and the reaction between methanol and ammonium chloride in a single reactor. Methanol is vaporized and enters a fluidized bed reactor from the bottom. Solid ammonium chloride is mechanically conveyed into the lower part of the fluidized bed. The reacted gases are separated and purified to obtain chloromethane and ammonia. However, because the solid ammonium chloride enters the reactor from the bottom, the reaction between ammonium chloride and methanol is not fully completed, and the temperature is insufficient for the ammonium chloride to be fully decomposed. Therefore, a heat exchange tube is needed to provide heat. However, the introduction of heat exchange tubes can easily cause carbon buildup on the surface of methanol vapor, resulting in methanol waste and increasing the difficulty of equipment processing. Chinese patent CN201010518835.8 discloses an apparatus for preparing chloromethane and ammonia using ammonium chloride and methanol. It has two mutually perpendicular vertical baffles inside, dividing the bed into four interconnected zones, where heat supply, chloromethane synthesis, catalyst circulation, and regeneration are simultaneously completed. However, such an apparatus suffers from complex operation and difficult processing.

[0006] Ammonium chloride raw materials mainly come from the soda ash industry, which contains a small amount of sodium carbonate or sodium bicarbonate impurities. In the high-temperature and hydrogen chloride-rich environment in the reactor, sodium carbonate and sodium bicarbonate are converted into high-melting-point sodium chloride, which is deposited on the inner wall of the reactor and the surface of the catalyst, causing catalyst deactivation. The deactivated catalyst cannot be regenerated by simple high-temperature carbon burning. Summary of the Invention

[0007] To address the problems of catalyst deactivation and regeneration difficulties caused by sodium chloride deposition, this invention provides a method that simultaneously uses ammonium chloride and hydrogen chloride as chlorine sources, separating the decomposition of ammonium chloride from the synthesis of chloromethane. A specially structured ammonium chloride feeding device is employed to resolve the impact of impurity deposition on the catalyst and the ammonium chloride feeding problem. This invention is achieved through the following technical solutions:

[0008] This invention discloses an apparatus for producing chloromethane using ammonium chloride and hydrogen chloride as chlorine sources, comprising a methanol vaporizer, a methanol superheater, a hydrogen chloride heater, an ammonium chloride feeder, an ammonium chloride decomposition reactor, and a fluidized bed synthesis reactor. The lower side inlet of the methanol vaporizer is connected to a methanol feed pipe, the top outlet of the methanol vaporizer is connected to the bottom inlet of the methanol superheater, and the top outlet of the methanol superheater is connected to the bottom inlet of the fluidized bed synthesis reactor. The tube-side inlet of the hydrogen chloride heater is connected to a hydrogen chloride gas feed pipe, and the tube-side outlet of the hydrogen chloride heater is connected to the bottom inlet of the fluidized bed synthesis reactor. The outlet of the ammonium chloride feeder is connected to the ammonium chloride feed pipe at the top of the ammonium chloride decomposition reactor. The hydrogen chloride gas feed pipe is connected to the hydrogen chloride gas inlet pipe on the ammonium chloride feed pipe. The gas outlet pipe on the upper side of the ammonium chloride decomposition reactor is connected to the gas inlet pipe on the lower side of the fluidized bed synthesis reactor. The top outlet of the fluidized bed synthesis reactor is connected to a product gas pipe. The ammonium chloride feeder is a closed type.

[0009] Preferably, the ammonium chloride decomposition reactor is a fluidized bed reactor, consisting of a reactor shell, a heater, a distributor, and an ammonium chloride feed pipe. The ammonium chloride feed pipe is a vertically installed three-pipe structure, connected and sealed to the top end cap of the ammonium chloride decomposition reactor via a flange at the top of the outer pipe. The top of the ammonium chloride feed pipe extends upward through an inner pipe to connect to the outlet of the ammonium chloride feeder, and the lower part extends downward to the straight section of the ammonium chloride decomposition reactor. The outer wall of the ammonium chloride feed pipe is covered with high-temperature resistant insulation material. A hydrogen chloride gas inlet pipe is installed at the top of the middle pipe of the ammonium chloride feed pipe. A cooling water inlet and a cooling water outlet are respectively installed on the upper side of the outer pipe of the ammonium chloride feed pipe. The heater is respectively equipped with a molten salt inlet pipe and a molten salt outlet pipe. The ammonium chloride decomposition reactor is filled with 80-200 mesh alumina powder as fluidizing particles. The heating medium in the heater is molten salt.

[0010] Preferably, the fluidized bed synthesis reactor consists of a synthesis reactor shell, a gas distributor, and a cooler; the cooler is equipped with a molten salt inlet and a molten salt outlet for the cooling medium; the fluidized bed synthesis reactor is filled with 60-200 mesh alumina powder or 30-80 mesh activated carbon powder impregnated with catalytically active substances, as fluidized particles.

[0011] Preferably, the fluidized bed synthesis reactor is a tubular fixed bed reactor, in which molten salt is used as the cooling medium in the shell side, and alumina or activated carbon granular catalyst impregnated with catalytically active substances is packed in the tube side; the equivalent diameter of the catalyst particles is 3-5 mm; the outlet of the methanol superheater is connected to the top gas inlet of the tubular fixed bed reactor; the outlet of the hydrogen chloride heater is connected to the top gas inlet of the tubular fixed bed reactor; the gas outlet pipe of the ammonium chloride decomposition reactor is connected to the inlet pipe of the tubular fixed bed reactor on the top side of the tubular fixed bed reactor; the bottom outlet of the tubular fixed bed reactor is connected to the product gas pipe of the tubular fixed bed reactor; the molten salt outlet of the cooling medium is located on the upper side of the shell of the tubular fixed bed reactor, and the molten salt inlet of the cooling medium is located on the lower side of the shell of the tubular fixed bed reactor; the molten salt inlet and the molten salt outlet of the cooling medium are 180° apart in the circumferential position of the shell of the tubular fixed bed reactor.

[0012] Preferably, the outlet of the cooling medium molten salt on the fluidized bed synthesis reactor is connected to the inlet pipe of the heating medium molten salt of the heater via a further heating device, and the outlet pipe of the heating medium molten salt of the heater is connected to the inlet pipe of the cooling medium molten salt.

[0013] Preferably, the outlet of the cooling medium molten salt of the tubular fixed bed reactor in the self-tube fixed bed reactor is connected to the inlet pipe of the heating medium molten salt of the heater via a further heating device, and the outlet pipe of the heating medium molten salt of the heater is also connected.

[0014] It is connected to the molten salt inlet of the cooling medium in a tubular fixed-bed reactor.

[0015] The method for producing chloromethane using the aforementioned apparatus that uses ammonium chloride and hydrogen chloride as chlorine sources includes the following steps:

[0016] a. Add alumina powder to the ammonium chloride decomposition reactor, and add catalyst to the fluidized bed synthesis reactor or tubular fixed bed reactor; pump heated molten salt into the heater and cooler respectively through the heating medium molten salt inlet pipe and the cooling medium molten salt inlet pipe, or pump heated molten salt into the shell side of the tubular fixed bed reactor through the cooling medium molten salt inlet pipe, preheating the ammonium chloride decomposition reactor and the fluidized bed synthesis reactor or tubular fixed bed reactor to the specified temperature; introduce high-temperature heating medium into the methanol vaporizer, methanol superheater, and hydrogen chloride heater respectively, heating to the specified temperature; add ammonium chloride powder into the ammonium chloride feeder; and introduce flowing cooling water into the outer sleeve of the ammonium chloride feed pipe through the cooling water inlet and the cooling water outlet pipe;

[0017] b. The hydrogen chloride gas from the hydrogen chloride gas feed pipe is divided into two parts: one part enters the inner tube of the ammonium chloride feed pipe through the hydrogen chloride gas inlet pipe, and then enters the ammonium chloride decomposition reactor together with the ammonium chloride powder; the other part is preheated by the hydrogen chloride heater to obtain high-temperature hydrogen chloride gas, and then distributed to the bottom of the ammonium chloride decomposition reactor and the bottom of the fluidized bed synthesis reactor or the top of the tubular fixed bed reactor.

[0018] c. Under the action of hydrogen chloride gas entering from the bottom, the alumina powder in the ammonium chloride decomposition reactor is in a fluidized state; the ammonium chloride powder is conveyed to the inner tube of the ammonium chloride feed pipe by the ammonium chloride feeder. Under the low-temperature environment of cooling water in the outer tube of the ammonium chloride feed pipe, the ammonium chloride powder, together with the hydrogen chloride gas entering from the hydrogen chloride gas inlet pipe, falls into the fluidized bed of alumina powder in the ammonium chloride decomposition reactor, and is sublimated or decomposed into ammonium chloride gas by heating. It mixes with the hydrogen chloride gas as the fluidizing medium, and the ammonium chloride and hydrogen chloride mixed gas is obtained at the top of the ammonium chloride decomposition reactor and discharged from the gas outlet pipe;

[0019] d. Liquid methanol feedstock enters the methanol vaporizer via the methanol feedstock pipe to obtain saturated methanol vapor, which then enters the methanol superheater for further heating to obtain superheated methanol vapor, and then enters the chloromethane synthesis reactor. For the fluidized bed synthesis reactor process, the superheated methanol vapor enters the bottom of the fluidized bed synthesis reactor and mixes with high-temperature hydrogen chloride gas from the hydrogen chloride heater to obtain a methanol-hydrogen chloride mixture, which enters the fluidized bed synthesis reactor via a gas distributor. For the tubular fixed bed reactor process, the superheated methanol vapor enters from the top of the tubular fixed bed reactor and mixes with high-temperature hydrogen chloride gas from the hydrogen chloride heater to obtain a methanol-hydrogen chloride mixture, which enters the tubular fixed bed reactor.

[0020] e. The ammonium chloride and hydrogen chloride mixed gas exiting from the gas outlet pipe enters a fluidized bed synthesis reactor or a tubular fixed bed reactor. For the fluidized bed synthesis reactor process, the ammonium chloride and hydrogen chloride mixed gas enters the fluidized bed synthesis reactor through the inlet pipe, and together with the methanol and hydrogen chloride mixed gas entering from the bottom, enters the catalyst fluidized bed layer for sufficient contact to undergo the chloromethane synthesis reaction, yielding a reaction product mixed gas containing chloromethane, ammonia, water vapor, and small amounts of dimethyl ether and methylamine byproducts. For the tubular fixed bed reactor process, the ammonium chloride and hydrogen chloride mixed gas enters the upper part of the tubular fixed bed reactor through the inlet pipe, and together with the methanol and hydrogen chloride mixed gas, enters the tube side containing catalyst particles for sufficient contact to undergo the chloromethane synthesis reaction, yielding a reaction product mixed gas containing chloromethane, ammonia, water vapor, and small amounts of dimethyl ether and methylamine byproducts.

[0021] f. The reaction product mixed gas enters the separation process from the top of the fluidized bed synthesis reactor via the product gas pipe to obtain chloromethane and liquid ammonia products; or, the reaction product mixed gas enters the separation process from the bottom of the tubular fixed bed reactor via the tubular fixed bed reactor product gas pipe to obtain chloromethane and liquid ammonia products.

[0022] Preferably, the outlet temperature of the hydrogen chloride gas from the hydrogen chloride heater is 220–300°C, and the operating pressure is 0.05–0.2 MPa; the outlet temperature of the methanol superheater is 150–250°C, and the operating pressure is 0.05–0.2 MPa; the operating temperature of the ammonium chloride decomposition reactor is 320–400°C, the operating pressure is 0.05–0.2 MPa, and the empty tower gas velocity of hydrogen chloride is 0.1–0.5 m / s; the closed ammonium chloride feeder is protected by nitrogen purging, and the pressure is maintained at 0.06–0.22 MPa.

[0023] Preferably, the fluidized bed synthesis reactor operates at a temperature of 300–380°C, an operating pressure of 0.05–0.2 MPa, and a standard space velocity of 200–1000 h⁻¹. -1 The tubular fixed-bed reactor operates at a temperature of 300–360°C, an operating pressure of 0.05–0.2 MPa, and a standard space velocity of 200–800 h⁻¹. -1 .

[0024] Preferably, the pipelines entering the fluidized bed synthesis reactor or the tubular fixed bed reactor need to be insulated, with the pipeline insulation temperature for the ammonium chloride and hydrogen chloride mixed gas being 310–390°C; and the pipeline insulation temperature for the methanol superheated vapor and the hydrogen chloride high-temperature gas being 200–250°C.

[0025] Compared with the prior art, the technical solution of the present invention has the following advantages and beneficial effects:

[0026] (1) The decomposition of ammonium chloride and the synthesis of chloromethane are carried out separately to avoid the deposition, blockage and deactivation of the catalyst caused by the salt impurities contained in ammonium chloride.

[0027] (2) The introduction of hydrogen chloride gas solves the problem of fluidizing gas source in the ammonium chloride decomposition reactor and ensures the stable operation of the ammonium chloride decomposition fluidized bed reactor; at the same time, the addition of hydrogen chloride can increase the heat released in the chloromethane synthesis reaction process, and provide heat for the ammonium chloride decomposition reaction process through the circulation of heat exchange medium, so as to reduce the external heat supply.

[0028] (3) A three-tube ammonium chloride feeding device is adopted, which keeps the ammonium chloride at a low temperature when it enters the high-temperature reactor, and avoids the squeezing between particles when the ammonium chloride is fed, thus effectively solving the problem of blockage in the ammonium chloride feeding pipe.

[0029] This invention has wide applications and broad market prospects. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the fluidized bed synthesis reactor process described in this invention.

[0031] Figure 2 This is a schematic diagram of the structure of the ammonium chloride decomposition reactor described in this invention.

[0032] Figure 3 This is a schematic diagram of the tubular fixed-bed reactor process described in this invention.

[0033] Explanation of each part in the diagram:

[0034] 1—Methanol vaporizer, 2—Methanol superheater, 3—Hydrogen chloride heater, 4—Ammonium chloride feeder, 5—Ammonium chloride decomposition reactor, 6—Fluidized bed synthesis reactor, 7—Methanol feedstock pipe, 8—Hydrogen chloride gas feedstock pipe, 9—Ammonium chloride feed pipe, 10—Hydrogen chloride gas inlet pipe, 11—Gas outlet pipe, 12—Inlet pipe, 13—Product gas pipe, 14—Decomposition reactor shell, 15—Heater, 16—Distributor, 17—Cooling water inlet, 18—Cooling water outlet, 1 9—Inlet pipe for heating medium molten salt; 20—Outlet pipe for heating medium molten salt; 21—Shell of synthesis reactor; 22—Gas distributor; 23—Cooler; 24—Inlet for cooling medium molten salt; 25—Outlet for cooling medium molten salt; 26—Tube-type fixed-bed reactor; 27—Product gas pipe for tube-type fixed-bed reactor; 28—Inlet for cooling medium molten salt for tube-type fixed-bed reactor; 29—Outlet for cooling medium molten salt for tube-type fixed-bed reactor; 30—Inlet pipe for tube-type fixed-bed reactor. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0036] Combination Figures 1-3 .

[0037] This invention discloses an apparatus for producing chloromethane using ammonium chloride and hydrogen chloride as chlorine sources, comprising a methanol vaporizer 1, a methanol superheater 2, a hydrogen chloride heater 3, an ammonium chloride feeder 4, an ammonium chloride decomposition reactor 5, and a fluidized bed synthesis reactor 6. The lower side inlet of the methanol vaporizer 1 is connected to a methanol feedstock pipe 7, the top outlet of the methanol vaporizer 1 is connected to the bottom inlet of the methanol superheater 2, and the top outlet of the methanol superheater 2 is connected to the bottom inlet of the fluidized bed synthesis reactor 6. The tube-side inlet of the hydrogen chloride heater 3 is connected to a hydrogen chloride gas feedstock pipe 8. The outlet of the hydrogen chloride heater 3 is connected to the bottom inlet of the fluidized bed synthesis reactor 6; the outlet of the ammonium chloride feeder 4 is connected to the ammonium chloride feed pipe 9 at the top of the ammonium chloride decomposition reactor 5; the hydrogen chloride gas feed pipe 8 is connected to the hydrogen chloride gas inlet pipe 10 on the ammonium chloride feed pipe 9; the gas outlet pipe 11 on the upper side of the ammonium chloride decomposition reactor 5 is connected to the gas inlet pipe 12 on the lower side of the fluidized bed synthesis reactor 6; the top outlet of the fluidized bed synthesis reactor 6 is connected to the product gas pipe 13; the ammonium chloride feeder 4 is a closed type.

[0038] Preferably, the ammonium chloride decomposition reactor 5 is a fluidized bed reactor, consisting of a reactor shell 14, a heater 15, a distributor 16, and an ammonium chloride feed pipe 9. The ammonium chloride feed pipe 9 is a vertically installed three-pipe structure, which is connected and sealed to the top end cap of the ammonium chloride decomposition reactor 5 through a flange on the upper part of the outer pipe. The top of the ammonium chloride feed pipe 9 extends upward through an inner pipe and connects to the outlet of the ammonium chloride feeder 4, while the lower part extends downward to the straight section of the ammonium chloride decomposition reactor 5. The outer wall of the ammonium chloride feed pipe 9 is covered with high-temperature resistant insulation material. A hydrogen chloride gas inlet pipe 10 is installed at the top of the middle pipe of the ammonium chloride feed pipe 9. A cooling water inlet 17 and a cooling water outlet 18 are respectively installed on the upper side of the outer pipe of the ammonium chloride feed pipe 9. The heater 15 is respectively provided with a molten salt inlet pipe 19 and a molten salt outlet pipe 20. The ammonium chloride decomposition reactor 5 is filled with 80-200 mesh alumina powder as fluidized particles. The heating medium in the heater 15 is molten salt.

[0039] Preferably, the fluidized bed synthesis reactor 6 is composed of a synthesis reactor shell 21, a gas distributor 22, and a cooler 23; the cooler 23 is equipped with a molten salt inlet 24 and a molten salt outlet 25; the fluidized bed synthesis reactor 6 is filled with 60-200 mesh alumina powder or 30-80 mesh activated carbon powder impregnated with catalytic active material, as fluidized particles.

[0040] Preferably, the fluidized bed synthesis reactor 6 is a tubular fixed bed reactor 26, in which molten salt is used as the cooling medium in the shell side, and alumina or activated carbon granular catalyst impregnated with catalytically active substances is packed in the tube side; the equivalent diameter of the catalyst particles is 3-5 mm; the outlet of the methanol superheater 2 is connected to the gas inlet at the top of the tubular fixed bed reactor 26; the outlet of the hydrogen chloride heater 3 is connected to the gas inlet at the top of the tubular fixed bed reactor 26; and the gas outlet pipe 11 of the ammonium chloride decomposition reactor 5 is connected to the tubular outlet pipe on the top side of the tubular fixed bed reactor 26. The fixed-bed reactor inlet pipe 30 is connected; the bottom outlet of the tubular fixed-bed reactor 26 is connected to the product gas pipe 27 of the tubular fixed-bed reactor; the tubular fixed-bed reactor cooling medium molten salt outlet 29 is provided on the upper side of the shell of the tubular fixed-bed reactor 26, and the tubular fixed-bed reactor cooling medium molten salt inlet 28 is provided on the lower side of the shell of the tubular fixed-bed reactor 26. The tubular fixed-bed reactor cooling medium molten salt inlet 28 and the tubular fixed-bed reactor cooling medium molten salt outlet 29 are 180° apart in the circumferential position of the shell of the tubular fixed-bed reactor 26.

[0041] Preferably, the cooling medium molten salt outlet 25 on the fluidized bed synthesis reactor 6 is connected to the heating medium molten salt inlet pipe 19 of the heater 15 via a further heating device, and the heating medium molten salt outlet pipe 20 of the heater 15 is connected to the cooling medium molten salt inlet 24.

[0042] Preferably, the molten salt outlet 29 of the tubular fixed bed reactor cooling medium of the tubular fixed bed reactor 26 is connected to the molten salt inlet pipe 19 of the heater 15 via a further heating device, and the molten salt outlet pipe 20 of the heater 15 is connected to the molten salt inlet 28 of the tubular fixed bed reactor cooling medium.

[0043] A method for using the chloromethane synthesis apparatus according to claims 1-6, characterized by comprising the following steps:

[0044] a. Add alumina powder to ammonium chloride decomposition reactor 5, and add catalyst to fluidized bed synthesis reactor 6 or tubular fixed bed reactor 26; pump heated molten salt into heater 15 and cooler 23 through heating medium molten salt inlet pipe 19 and cooling medium molten salt inlet pipe 24 respectively, or pump heated molten salt into the shell side of tubular fixed bed reactor 26 through tubular fixed bed reactor cooling medium molten salt inlet pipe 28, preheating ammonium chloride decomposition reactor 5 and fluidized bed synthesis reactor 6 or tubular fixed bed reactor 26 to the specified temperature; introduce high temperature heating medium into methanol gasifier 1, methanol superheater 2, and hydrogen chloride heater 3 respectively, heating to the specified temperature; add ammonium chloride powder to ammonium chloride feeder 4; and introduce flowing cooling water into the outer sleeve of ammonium chloride feed pipe 9 through cooling water inlet pipe 17 and cooling water outlet pipe 18;

[0045] b. Part of the hydrogen chloride gas from the hydrogen chloride gas feed pipe 8 enters the inner tube of the ammonium chloride feed pipe 9 through the hydrogen chloride gas inlet pipe 10, and then enters the ammonium chloride decomposition reactor 5 together with the ammonium chloride powder; the other part is preheated by the hydrogen chloride heater 3 to obtain high-temperature hydrogen chloride gas, and then distributed in two ways to enter the bottom of the ammonium chloride decomposition reactor 5 and the bottom of the fluidized bed synthesis reactor 6 or the top of the tubular fixed bed reactor 26 respectively.

[0046] c. Under the action of hydrogen chloride gas entering from the bottom, the alumina powder in the ammonium chloride decomposition reactor 5 is in a fluidized state; the ammonium chloride powder is conveyed to the inner tube of the ammonium chloride feed pipe 9 by the ammonium chloride feeder 4. Under the low-temperature environment of cooling water in the outer tube of the ammonium chloride feed pipe 9, the ammonium chloride powder, together with the hydrogen chloride gas entering from the hydrogen chloride gas inlet pipe 10, falls into the fluidized bed of alumina powder in the ammonium chloride decomposition reactor 5, and is sublimated or decomposed into ammonium chloride gas by heating. It is mixed with the hydrogen chloride gas as the fluidizing medium, and the ammonium chloride and hydrogen chloride mixed gas is obtained at the top of the ammonium chloride decomposition reactor 5 and discharged from the gas outlet pipe 11.

[0047] d. Liquid methanol feedstock enters methanol vaporizer 1 via methanol feedstock pipe 7 for vaporization to obtain saturated methanol vapor, which then enters methanol superheater 2 for further heating to obtain superheated methanol vapor, and then enters chloromethane synthesis reactor; for the fluidized bed synthesis reactor 6 process, superheated methanol vapor enters the bottom of fluidized bed synthesis reactor 6 and mixes with high-temperature hydrogen chloride gas from hydrogen chloride heater 3 to obtain methanol-hydrogen chloride mixed gas, which enters fluidized bed synthesis reactor 6 via gas distributor 22; for the tubular fixed bed reactor 26 process, superheated methanol vapor enters from the top of tubular fixed bed reactor 26 and mixes with high-temperature hydrogen chloride gas from hydrogen chloride heater 3 to obtain methanol-hydrogen chloride mixed gas, which enters tubular fixed bed reactor 26;

[0048] e. The ammonium chloride and hydrogen chloride mixed gas exiting from the gas outlet pipe 11 enters the fluidized bed synthesis reactor 6 or the tubular fixed bed reactor 26. For the fluidized bed synthesis reactor 6 process, the ammonium chloride and hydrogen chloride mixed gas enters the fluidized bed synthesis reactor 6 through the inlet pipe 12, and together with the methanol and hydrogen chloride mixed gas entering from the bottom, enters the catalyst fluidized bed layer to fully contact and undergo the chloromethane synthesis reaction, obtaining a reaction product mixed gas containing chloromethane, ammonia, water vapor, and a small amount of dimethyl ether and methylamine byproducts. For the tubular fixed bed reactor 26 process, the ammonium chloride and hydrogen chloride mixed gas enters the upper part of the tubular fixed bed reactor 26 through the tubular fixed bed reactor inlet pipe 30, and together with the methanol and hydrogen chloride mixed gas, enters the tube side containing catalyst particles to fully contact and undergo the chloromethane synthesis reaction, obtaining a reaction product mixed gas containing chloromethane, ammonia, water vapor, and a small amount of dimethyl ether and methylamine byproducts.

[0049] f. The reaction product mixed gas enters the separation process from the top of the fluidized bed synthesis reactor 6 via the product gas pipe 13 to obtain chloromethane and liquid ammonia products; or, the reaction product mixed gas enters the separation process from the bottom of the tubular fixed bed reactor 26 via the tubular fixed bed reactor product gas pipe 27 to obtain chloromethane and liquid ammonia products.

[0050] Preferably, the outlet temperature of the hydrogen chloride gas in the hydrogen chloride heater 3 is 220–300°C, and the operating pressure is 0.05–0.2 MPa; the outlet temperature of the methanol superheater 2 is 150–250°C, and the operating pressure is 0.05–0.2 MPa; the operating temperature of the ammonium chloride decomposition reactor 5 is 320–400°C, the operating pressure is 0.05–0.2 MPa, and the empty tower gas velocity of hydrogen chloride gas is 0.1–0.5 m / s; the closed ammonium chloride feeder 4 is protected by nitrogen purging, and the pressure is maintained at 0.06–0.22 MPa.

[0051] Preferably, the fluidized bed synthesis reactor 6 operates at a temperature of 300–380°C, an operating pressure of 0.05–0.2 MPa, and a standard space velocity of 200–1000 h⁻¹. -1 The tubular fixed-bed reactor 26 operates at a temperature of 300–360°C, an operating pressure of 0.05–0.2 MPa, and a standard space velocity of 200–800 h⁻¹. -1 .

[0052] Preferably, the pipelines entering the fluidized bed synthesis reactor 6 or the tubular fixed bed reactor 26 need to be insulated. The insulation temperature of the pipeline for the ammonium chloride and hydrogen chloride mixed gas is 310-390°C; the insulation temperature of the pipeline for the methanol superheated vapor and the hydrogen chloride high-temperature gas is 200-250°C.

[0053] Example 1

[0054] Alumina powder with an average particle size of 100 mesh is added to the ammonium chloride decomposition reactor 5, and alumina powder catalyst impregnated with nickel active components with an average particle size of 100 mesh is added to the fluidized bed synthesis reactor 6. Molten salt at a temperature of 350°C is pumped into the heater 15 and cooler 23 through the molten salt inlet pipe 19 (heating medium) and the molten salt inlet pipe 24 (cooling medium), respectively, preheating the ammonium chloride decomposition reactor 5 and the fluidized bed synthesis reactor 6 to 320°C. Superheated steam is introduced into the methanol vaporizer 1, methanol superheater 2, and hydrogen chloride heater 3, respectively. Ammonium chloride powder is added to the ammonium chloride feeder 4. Flowing cooling water is introduced into the outer casing of the ammonium chloride feed pipe 9 through the cooling water inlet 17 and the cooling water outlet 18. The pipeline insulation temperature for the ammonium chloride and hydrogen chloride mixed gas is 320°C, and the pipeline insulation temperature for the methanol superheated steam and hydrogen chloride high-temperature gas is 220°C.

[0055] Hydrogen chloride gas from hydrogen chloride gas feedstock pipe 8 is divided into two streams. One stream, at a flow rate of 0.02 kmol / h, enters the inner tube of ammonium chloride feedstock pipe 9 through hydrogen chloride gas inlet pipe 10. The other stream, at a flow rate of 1.98 kmol / h, enters hydrogen chloride heater 3 and is heated to 230°C to obtain high-temperature hydrogen chloride gas. Of this, 1.5 kmol / h enters ammonium chloride decomposition reactor 5 from the bottom, and 0.48 kmol / h directly enters the bottom of fluidized bed synthesis reactor 6. The operating pressure of hydrogen chloride heater 3 is 0.12 MPa.

[0056] Under the influence of hydrogen chloride gas entering from the bottom, the alumina powder in the ammonium chloride decomposition reactor 5 is in a fluidized state. The ammonium chloride feeder 4 is started, and ammonium chloride particles are added to the inner tube of the ammonium chloride feed pipe 9 at a feed flow rate of 2 kmol / h. Subsequently, they fall into the fluidized bed of alumina powder in the ammonium chloride decomposition reactor 5 together with the hydrogen chloride gas entering through the hydrogen chloride gas inlet pipe 10. The ammonium chloride particles are subjected to uniform high temperature in the fluidized bed, sublimating or decomposing into ammonium chloride gas, which mixes with the hydrogen chloride gas serving as the fluidizing medium, forming an ammonium chloride-hydrogen chloride mixture at the top of the ammonium chloride decomposition reactor 5. The operating temperature of the ammonium chloride decomposition reactor 5 is 350℃, the operating pressure is 0.11 MPa, and the hydrogen chloride empty tower gas velocity is 0.25 m / s. The nitrogen sealing pressure of the ammonium chloride feeder 4 is 0.12 MPa.

[0057] The ammonium chloride-hydrogen chloride mixture exiting from the top gas outlet pipe 11 of the ammonium chloride decomposition reactor 5 enters the fluidized bed synthesis reactor 6 through the inlet pipe 12. 4.2 kmol of liquid methanol enters the methanol vaporizer 1 through the methanol feed pipe 7, and after vaporization, enters the methanol superheater 2 to obtain superheated methanol vapor at 220°C. This vapor, along with 0.48 kmol / h of hydrogen chloride gas, forms a methanol-hydrogen chloride mixture, which enters the catalytic bed of the fluidized bed synthesis reactor 6 through the distributor 16. There, it comes into full contact with the ammonium chloride-hydrogen chloride mixture, and under the action of the catalyst, a chloromethane synthesis reaction occurs, yielding a reaction product mixture containing chloromethane, ammonia, water vapor, and small amounts of dimethyl ether and methylamine byproducts. The fluidized bed synthesis reactor 6 operates at a temperature of 350°C, an operating pressure of 0.09 MPa, and a space velocity of 500 h⁻¹. -1 The operating pressure of methanol vaporizer 1 and methanol superheater 2 is 0.10 MPa.

[0058] The reaction product mixed gas enters the separation process through the product gas pipe 13 from the top of the fluidized bed synthesis reactor 6. After separation, 3.89 kmol / h of chloromethane and 1.96 kmol / h of liquid ammonia and a small amount of by-products are obtained. The yield of chloromethane based on methanol is 92.6%.

[0059] Example 2

[0060] Alumina powder with an average particle size of 80 mesh is added to the ammonium chloride decomposition reactor 5, and alumina powder catalyst impregnated with nickel active components with an average particle size of 120 mesh is added to the fluidized bed synthesis reactor 6. Molten salt at a temperature of 380°C is pumped into the heater 15 and cooler 23 through the molten salt inlet pipe 19 (heating medium) and the molten salt inlet pipe 24 (cooling medium), respectively, preheating the ammonium chloride decomposition reactor 5 and the fluidized bed synthesis reactor 6 to 330°C. Superheated steam is introduced into the methanol vaporizer 1, methanol superheater 2, and hydrogen chloride heater 3, respectively. Ammonium chloride powder is added to the ammonium chloride feeder 4. Flowing cooling water is introduced into the outer casing of the ammonium chloride feed pipe 9 through the cooling water inlet 17 and the cooling water outlet 18. The pipeline insulation temperature for the ammonium chloride and hydrogen chloride mixed gas is 330°C, and the pipeline insulation temperature for the methanol superheated steam and high-temperature hydrogen chloride gas is 230°C.

[0061] Hydrogen chloride gas from hydrogen chloride gas feed pipe 8 is divided into two streams. One stream, at a flow rate of 0.02 kmol / h, enters the inner tube of ammonium chloride feed pipe 9 through hydrogen chloride gas inlet pipe 10. The other stream, at a flow rate of 2.48 kmol / h, enters hydrogen chloride heater 3 and is heated to 240°C to obtain high-temperature hydrogen chloride gas. Of this, 2.0 kmol / h enters ammonium chloride decomposition reactor 5 from the bottom, and 0.48 kmol / h directly enters the bottom of fluidized bed synthesis reactor 6. The operating pressure of hydrogen chloride heater 3 is 0.2 MPa.

[0062] Under the influence of hydrogen chloride gas entering from the bottom, the alumina powder in the ammonium chloride decomposition reactor 5 is in a fluidized state. The ammonium chloride feeder 4 is started, and ammonium chloride particles are added to the inner tube of the ammonium chloride feed pipe 9 at a feed flow rate of 3 kmol / h. Subsequently, they fall into the fluidized bed of alumina powder in the ammonium chloride decomposition reactor 5 together with the hydrogen chloride gas entering through the hydrogen chloride gas inlet pipe 10. The ammonium chloride particles are subjected to uniform high temperature in the fluidized bed, sublimating or decomposing into ammonium chloride gas, which mixes with the hydrogen chloride gas serving as the fluidizing medium, forming an ammonium chloride-hydrogen chloride mixture at the top of the ammonium chloride decomposition reactor 5. The operating temperature of the ammonium chloride decomposition reactor 5 is 360℃, the operating pressure is 0.18 MPa, and the hydrogen chloride empty tower gas velocity is 0.35 m / s. The nitrogen sealing pressure of the ammonium chloride feeder 4 is 0.2 MPa.

[0063] The ammonium chloride-hydrogen chloride mixture exiting from the top gas outlet pipe 11 of the ammonium chloride decomposition reactor 5 enters the fluidized bed synthesis reactor 6 through the inlet pipe 12. 5.7 kmol of liquid methanol enters the methanol vaporizer 1 through the methanol feed pipe 7, and after vaporization, enters the methanol superheater 2 to obtain superheated methanol vapor at 220°C. This vapor, along with 0.48 kmol / h of hydrogen chloride gas, forms a methanol-hydrogen chloride mixture, which enters the catalytic bed of the fluidized bed synthesis reactor 6 through the distributor 16. There, it comes into full contact with the ammonium chloride-hydrogen chloride mixture, and under the action of the catalyst, a chloromethane synthesis reaction occurs, yielding a reaction product mixture containing chloromethane, ammonia, water vapor, and small amounts of dimethyl ether and methylamine byproducts. The fluidized bed synthesis reactor 6 operates at a temperature of 330°C, an operating pressure of 0.15 MPa, and a space velocity of 800 h⁻¹. -1 The operating pressure of methanol vaporizer 1 and methanol superheater 2 is 0.18 MPa.

[0064] The reaction product mixed gas enters the separation process through the product gas pipe 13 from the top of the fluidized bed synthesis reactor 6. After separation, 5.38 kmol / h of chloromethane and 2.97 kmol / h of liquid ammonia and a small amount of by-products are obtained, with a methanol yield of 94.3%.

[0065] Example 3

[0066] Alumina powder with an average particle size of 120 mesh is added to the ammonium chloride decomposition reactor 5, and alumina powder catalyst impregnated with nickel active components with an average particle size of 80 mesh is added to the fluidized bed synthesis reactor 6. Molten salt at a preheated temperature of 360°C is pumped into the heater 15 and cooler 23 through the molten salt inlet pipe 19 (heating medium) and the molten salt inlet pipe 24 (cooling medium), respectively, preheating the ammonium chloride decomposition reactor 5 and the fluidized bed synthesis reactor 6 to 323°C. Superheated steam is introduced into the methanol vaporizer 1, methanol superheater 2, and hydrogen chloride heater 3, respectively. Ammonium chloride powder is added to the ammonium chloride feeder 4. Flowing cooling water is introduced into the outer casing of the ammonium chloride feed pipe 9 through the cooling water inlet 17 and the cooling water outlet 18. The pipeline insulation temperature for the ammonium chloride and hydrogen chloride mixed gas is 310°C, and the pipeline insulation temperature for the methanol superheated steam and hydrogen chloride high-temperature gas is 210°C.

[0067] Hydrogen chloride gas from hydrogen chloride gas feedstock pipe 8 is divided into two streams. One stream, at a flow rate of 0.04 kmol / h, enters the inner tube of ammonium chloride feedstock pipe 9 through hydrogen chloride gas inlet pipe 10. The other stream, at a flow rate of 3.96 kmol / h, enters hydrogen chloride heater 3 and is heated to 260°C to obtain high-temperature hydrogen chloride gas. Of this, 3.1 kmol / h enters ammonium chloride decomposition reactor 5 from the bottom, and 0.86 kmol / h directly enters the bottom of fluidized bed synthesis reactor 6. The operating pressure of hydrogen chloride heater 3 is 0.16 MPa.

[0068] Under the influence of hydrogen chloride gas entering from the bottom, the alumina powder in the ammonium chloride decomposition reactor 5 is in a fluidized state. The ammonium chloride feeder 4 is started, and ammonium chloride particles are added to the inner tube of the ammonium chloride feed pipe 9 at a feed flow rate of 5 kmol / h. Subsequently, they fall into the fluidized bed of alumina powder in the ammonium chloride decomposition reactor 5 together with the hydrogen chloride gas entering through the hydrogen chloride gas inlet pipe 10. The ammonium chloride particles are subjected to uniform high temperature in the fluidized bed, sublimating or decomposing into ammonium chloride gas, which mixes with the hydrogen chloride gas serving as the fluidizing medium, forming an ammonium chloride-hydrogen chloride mixture at the top of the ammonium chloride decomposition reactor 5. The operating temperature of the ammonium chloride decomposition reactor 5 is 340℃, the operating pressure is 0.15 MPa, and the hydrogen chloride empty tower gas velocity is 0.55 m / s. The nitrogen sealing pressure of the ammonium chloride feeder 4 is 0.16 MPa.

[0069] The ammonium chloride-hydrogen chloride mixture exiting from the top gas outlet pipe 11 of the ammonium chloride decomposition reactor 5 enters the fluidized bed synthesis reactor 6 through the inlet pipe 12. 5.7 kmol of liquid methanol enters the methanol vaporizer 1 through the methanol feed pipe 7, and after vaporization, enters the methanol superheater 2 to obtain superheated methanol vapor at 230°C. This vapor, along with 0.86 kmol / h of hydrogen chloride gas, forms a methanol-hydrogen chloride mixture, which enters the catalytic bed of the fluidized bed synthesis reactor 6 through the distributor 16. There, it comes into full contact with the ammonium chloride-hydrogen chloride mixture, and under the action of the catalyst, a chloromethane synthesis reaction occurs, yielding a reaction product mixture containing chloromethane, ammonia, water vapor, and small amounts of dimethyl ether and methylamine byproducts. The fluidized bed synthesis reactor 6 operates at a temperature of 360°C, an operating pressure of 0.12 MPa, and a space velocity of 1000 h⁻¹. -1 The operating pressure of methanol vaporizer 1 and methanol superheater 2 is 0.14 MPa.

[0070] The reaction product mixed gas enters the separation process through the product gas pipe 13 from the top of the fluidized bed synthesis reactor 6. After separation, 8.7 kmol / h of chloromethane and 4.98 kmol / h of liquid ammonia and a small amount of by-products are obtained, with a methanol yield of 93.5%.

[0071] Example 4

[0072] Alumina powder with an average particle size of 110 mesh is added to the ammonium chloride decomposition reactor 5, and activated carbon powder catalyst impregnated with nickel active components with an average particle size of 60 mesh is added to the fluidized bed synthesis reactor 6. Molten salt at a temperature of 340°C is pumped into the heater 15 and cooler 23 through the molten salt inlet pipe 19 (heating medium) and the molten salt inlet pipe 24 (cooling medium), respectively, preheating the ammonium chloride decomposition reactor 5 and the fluidized bed synthesis reactor 6 to 315°C. Superheated steam is introduced into the methanol vaporizer 1, methanol superheater 2, and hydrogen chloride heater 3, respectively. Ammonium chloride powder is added to the ammonium chloride feeder 4. Flowing cooling water is introduced into the outer casing of the ammonium chloride feed pipe 9 through the cooling water inlet 17 and the cooling water outlet 18. The pipeline insulation temperature for the ammonium chloride and hydrogen chloride mixed gas is 310°C, and the pipeline insulation temperature for the methanol superheated steam and hydrogen chloride high-temperature gas is 200°C.

[0073] Hydrogen chloride gas from hydrogen chloride gas feed pipe 8 is divided into two streams. One stream, at a flow rate of 0.03 kmol / h, enters the inner tube of ammonium chloride feed pipe 9 through hydrogen chloride gas inlet pipe 10. The other stream, at a flow rate of 2.47 kmol / h, enters hydrogen chloride heater 3 and is heated to 220°C to obtain high-temperature hydrogen chloride gas. Of this, 2.0 kmol / h enters ammonium chloride decomposition reactor 5 from the bottom, and 0.47 kmol / h directly enters the bottom of fluidized bed synthesis reactor 6. The operating pressure of hydrogen chloride heater 3 is 0.12 MPa.

[0074] Under the influence of hydrogen chloride gas entering from the bottom, the alumina powder in the ammonium chloride decomposition reactor 5 is in a fluidized state. The ammonium chloride feeder 4 is started, and ammonium chloride particles are added to the inner tube of the ammonium chloride feed pipe 9 at a feed flow rate of 3 kmol / h. Subsequently, they fall into the fluidized bed of alumina powder in the ammonium chloride decomposition reactor 5 together with the hydrogen chloride gas entering through the hydrogen chloride gas inlet pipe 10. The ammonium chloride particles are subjected to uniform high temperature in the fluidized bed, sublimating or decomposing into ammonium chloride gas, which mixes with the hydrogen chloride gas serving as the fluidizing medium, forming an ammonium chloride-hydrogen chloride mixture at the top of the ammonium chloride decomposition reactor 5. The operating temperature of the ammonium chloride decomposition reactor 5 is 330℃, the operating pressure is 0.10 MPa, and the hydrogen chloride empty tower gas velocity is 0.35 m / s. The nitrogen sealing pressure of the ammonium chloride feeder 4 is 0.12 MPa.

[0075] The ammonium chloride-hydrogen chloride mixture exiting from the top gas outlet pipe 11 of the ammonium chloride decomposition reactor 5 enters the fluidized bed synthesis reactor 6 through the inlet pipe 12. 5.7 kmol of liquid methanol enters the methanol vaporizer 1 through the methanol feed pipe 7, and after vaporization, enters the methanol superheater 2 to obtain superheated methanol vapor at 220°C. This vapor, along with 0.47 kmol / h of hydrogen chloride gas, forms a methanol-hydrogen chloride mixture, which enters the catalytic bed of the fluidized bed synthesis reactor 6 through the distributor 16. There, it comes into full contact with the ammonium chloride-hydrogen chloride mixture, and under the action of the catalyst, a chloromethane synthesis reaction occurs, yielding a reaction product mixture containing chloromethane, ammonia, water vapor, and small amounts of dimethyl ether and methylamine byproducts. The fluidized bed synthesis reactor 6 operates at a temperature of 320°C, an operating pressure of 0.08 MPa, and a space velocity of 800 h⁻¹. -1 The operating pressure of methanol vaporizer 1 and methanol superheater 2 is 0.10 MPa.

[0076] The reaction product mixed gas enters the separation process through the product gas pipe 13 from the top of the fluidized bed synthesis reactor 6. After separation, 5.35 kmol / h of chloromethane and 2.95 kmol / h of liquid ammonia and a small amount of by-products are obtained, with a methanol yield of 93.8%.

[0077] Example 5

[0078] Alumina powder with an average particle size of 110 mesh is added to the ammonium chloride decomposition reactor 5, and activated carbon catalyst particles impregnated with nickel active components with an average particle size of 4 mm are added to the tubular fixed-bed reactor 26. Molten salt heated to 380°C is pumped into the heater 15 through the molten salt inlet pipe 19, and molten salt heated to 380°C is pumped into the shell side of the tubular fixed-bed reactor 26 through the molten salt inlet pipe 28, thus preheating the tube sides of the ammonium chloride decomposition reactor 5 and the tubular fixed-bed reactor 26 to 320°C. Superheated steam is introduced into the methanol vaporizer 1, methanol superheater 2, and hydrogen chloride heater 3, respectively. Ammonium chloride powder is added to the ammonium chloride feeder 4. Flowing cooling water is introduced into the outer casing of the ammonium chloride feed pipe 9 through the cooling water inlet 17 and the cooling water outlet 18. The insulation temperature for the pipeline containing the ammonium chloride and hydrogen chloride mixed gas is 320℃, and the insulation temperature for the pipeline containing the methanol superheated vapor and the hydrogen chloride high-temperature gas is 220℃.

[0079] Hydrogen chloride gas from hydrogen chloride gas feed pipe 8 is divided into two streams. One stream, at a flow rate of 0.04 kmol / h, enters the inner tube of ammonium chloride feed pipe 9 through hydrogen chloride gas inlet pipe 10. The other stream, at a flow rate of 2.96 kmol / h, enters hydrogen chloride heater 3 and is heated to 250°C to obtain high-temperature hydrogen chloride gas. Of this, 2.3 kmol / h enters ammonium chloride decomposition reactor 5 from the bottom, and 0.66 kmol / h directly enters the top of tubular fixed-bed reactor 26. The operating pressure of hydrogen chloride heater 3 is 0.17 MPa.

[0080] Under the influence of hydrogen chloride gas entering from the bottom, the alumina powder in the ammonium chloride decomposition reactor 5 is in a fluidized state. The ammonium chloride feeder 4 is started, and ammonium chloride particles are added to the inner tube of the ammonium chloride feed pipe 9 at a feed flow rate of 3 kmol / h. Subsequently, they fall into the fluidized bed of alumina powder in the ammonium chloride decomposition reactor 5 together with the hydrogen chloride gas entering through the hydrogen chloride gas inlet pipe 10. The ammonium chloride particles are subjected to uniform high temperature in the fluidized bed, sublimating or decomposing into ammonium chloride gas, which mixes with the hydrogen chloride gas serving as the fluidizing medium, forming an ammonium chloride-hydrogen chloride mixture at the top of the ammonium chloride decomposition reactor 5. The operating temperature of the ammonium chloride decomposition reactor 5 is 340℃, the operating pressure is 0.18 MPa, and the hydrogen chloride empty tower gas velocity is 0.47 m / s. The nitrogen sealing pressure of the ammonium chloride feeder 4 is 0.20 MPa.

[0081] The ammonium chloride-hydrogen chloride mixture exiting from the top gas outlet pipe 11 of the ammonium chloride decomposition reactor 5 enters the top of the tubular fixed-bed reactor 26 via the inlet pipe 30. 5.7 kmol of liquid methanol enters the methanol vaporizer 1 through the methanol feed pipe 7, and after vaporization, enters the methanol superheater 2 to obtain superheated methanol vapor at 200°C. This vapor, along with 0.66 kmol / h of hydrogen chloride gas, forms a methanol-hydrogen chloride mixture. After sufficient contact with the ammonium chloride-hydrogen chloride mixture at the top of the tubular fixed-bed reactor 26, it enters the tube-side catalytic bed of the reactor. Under the action of the catalyst, a chloromethane synthesis reaction occurs, yielding a reaction product mixture containing chloromethane, ammonia, water vapor, and small amounts of dimethyl ether and methylamine byproducts. The operating temperature of the tube-side catalytic bed in the tubular fixed-bed reactor 26 is 330°C, the operating pressure is 0.15 MPa, and the space velocity is 910 h⁻¹. -1 The operating pressure of methanol vaporizer 1 and methanol superheater 2 is 0.17 MPa.

[0082] The reaction product mixed gas enters the separation process from the bottom of the tubular fixed-bed reactor 26 through the tubular fixed-bed reactor product gas pipe 27. After separation, 6.90 kmol / h of chloromethane and 3.97 kmol / h of liquid ammonia and a small amount of by-products are obtained. The yield of chloromethane to methanol is 94.5%.

Claims

1. An apparatus for producing chloromethane using ammonium chloride and hydrogen chloride as chlorine sources, characterized in that, The reactor includes a methanol vaporizer (1), a methanol superheater (2), a hydrogen chloride heater (3), an ammonium chloride feeder (4), an ammonium chloride decomposition reactor (5), and a fluidized bed synthesis reactor (6). The lower side inlet of the methanol vaporizer (1) is connected to a methanol feedstock pipe (7), the top outlet of the methanol vaporizer (1) is connected to the bottom inlet of the methanol superheater (2), and the top outlet of the methanol superheater (2) is connected to the bottom inlet of the fluidized bed synthesis reactor (6). The tube-side inlet of the hydrogen chloride heater (3) is connected to a hydrogen chloride gas feedstock pipe (8), and the tube-side outlet of the hydrogen chloride heater (3) is connected to the bottom inlet of the fluidized bed synthesis reactor (6). The outlet of the ammonium chloride feeder (4) is connected to the bottom inlet of the fluidized bed synthesis reactor (6); the outlet of the ammonium chloride feeder (4) is connected to the ammonium chloride feed pipe (9) at the top of the ammonium chloride decomposition reactor (5); the hydrogen chloride gas feed pipe (8) is connected to the hydrogen chloride gas inlet pipe (10) on the ammonium chloride feed pipe (9); the gas outlet pipe (11) on the upper side of the ammonium chloride decomposition reactor (5) is connected to the gas inlet pipe (12) on the lower side of the fluidized bed synthesis reactor (6); the top outlet of the fluidized bed synthesis reactor (6) is connected to the product gas pipe (13); the ammonium chloride feeder (4) is a closed type. The ammonium chloride decomposition reactor (5) is a fluidized bed reactor, consisting of a decomposition reactor shell (14), a heater (15), a distributor (16), and an ammonium chloride feed pipe (9). The ammonium chloride feed pipe (9) is a vertically installed three-pipe structure, which is connected and sealed to the top end cap of the ammonium chloride decomposition reactor (5) through the flange at the top of the outer pipe. The top of the ammonium chloride feed pipe (9) extends upward through the inner pipe and connects to the outlet of the ammonium chloride feeder (4), while the lower part extends downward to the straight section of the ammonium chloride decomposition reactor (5). The outer wall of the ammonium chloride feed pipe (9) is covered with high-temperature resistant insulation material; a hydrogen chloride gas inlet pipe (10) is installed at the top of the middle pipe of the ammonium chloride feed pipe (9); a cooling water inlet (17) and a cooling water outlet (18) are respectively installed on the upper side of the outer pipe of the ammonium chloride feed pipe (9); a molten salt inlet pipe (19) and a molten salt outlet pipe (20) are respectively provided on the heater (15); the ammonium chloride decomposition reactor (5) is filled with 80~200 mesh alumina powder as fluidizing particles; the heating medium in the heater (15) is molten salt; The fluidized bed synthesis reactor (6) consists of a synthesis reactor shell (21), a gas distributor (22), and a cooler (23); the cooler (23) is equipped with a molten salt inlet (24) and a molten salt outlet (25); the fluidized bed synthesis reactor (6) is filled with 60-200 mesh alumina powder or 30-80 mesh activated carbon powder impregnated with catalytic active material, as fluidized particles; The fluidized bed synthesis reactor (6) is a tubular fixed bed reactor (26). Molten salt is used as the cooling medium in its shell side, and alumina or activated carbon granular catalyst impregnated with catalytically active substances is installed in the tube side. The equivalent diameter of the catalyst particles is 3-5 mm. The outlet of the methanol superheater (2) is connected to the gas inlet at the top of the tubular fixed bed reactor (26). The outlet of the hydrogen chloride heater (3) is connected to the gas inlet at the top of the tubular fixed bed reactor (26). The gas outlet pipe (11) of the ammonium chloride decomposition reactor (5) is connected to the tubular fixed bed on the top side of the tubular fixed bed reactor (26). The reactor inlet pipe (30) is connected; the bottom outlet of the tubular fixed bed reactor (26) is connected to the product gas pipe (27) of the tubular fixed bed reactor; the tubular fixed bed reactor cooling medium molten salt outlet (29) is provided on the upper side of the shell of the tubular fixed bed reactor (26), and the tubular fixed bed reactor cooling medium molten salt inlet (28) is provided on the lower side of the shell of the tubular fixed bed reactor (26). The tubular fixed bed reactor cooling medium molten salt inlet (28) and the tubular fixed bed reactor cooling medium molten salt outlet (29) are 180° apart in the circumferential position of the shell of the tubular fixed bed reactor (26). The cooling medium molten salt outlet (25) of the fluidized bed synthesis reactor (6) is connected to the heating medium molten salt inlet pipe (19) of the heater (15) via a further heating device, and the heating medium molten salt outlet pipe (20) of the heater (15) is connected to the cooling medium molten salt inlet (24). The molten salt outlet (29) of the tubular fixed-bed reactor (26) is connected to the molten salt inlet pipe (19) of the heater (15) via a further heating device. The molten salt outlet pipe (20) of the heater (15) is connected to the molten salt inlet pipe (28) of the tubular fixed-bed reactor.

2. A method for producing chloromethane using the apparatus for producing chloromethane with ammonium chloride and hydrogen chloride as chlorine sources as described in claim 1, characterized in that: Includes the following steps: a. Add alumina powder to the ammonium chloride decomposition reactor (5), and add catalyst to the fluidized bed synthesis reactor (6) or tubular fixed bed reactor (26); pump heated molten salt into the heater (15) and cooler (23) through the heating medium molten salt inlet pipe (19) and cooling medium molten salt inlet pipe (24), respectively, or pump heated molten salt into the shell side of the tubular fixed bed reactor (26) through the cooling medium molten salt inlet pipe (28) of the tubular fixed bed reactor, preheat the ammonium chloride decomposition reactor (5) and fluidized bed synthesis reactor (6) or tubular fixed bed reactor (26) to the specified temperature; introduce high temperature heating medium into the methanol gasifier (1), methanol superheater (2), and hydrogen chloride heater (3), respectively, and heat to the specified temperature; add ammonium chloride powder into the ammonium chloride feeder (4); introduce flowing cooling water into the outer sleeve of the ammonium chloride feed pipe (9) through the cooling water inlet pipe (17) and cooling water outlet pipe (18); b. The hydrogen chloride gas from the hydrogen chloride gas feed pipe (8) is partially introduced into the inner tube of the ammonium chloride feed pipe (9) through the hydrogen chloride gas inlet pipe (10), and then enters the ammonium chloride decomposition reactor (5) together with the ammonium chloride powder; the other part is preheated by the hydrogen chloride heater (3) to obtain high-temperature hydrogen chloride gas, and then distributed in two stages to enter the bottom of the ammonium chloride decomposition reactor (5) and the bottom of the fluidized bed synthesis reactor (6) or the top of the tubular fixed bed reactor (26); c. Under the action of hydrogen chloride gas entering from the bottom, the alumina powder in the ammonium chloride decomposition reactor (5) is in a fluidized state; the ammonium chloride powder is transported to the inner tube of the ammonium chloride feed pipe (9) by the ammonium chloride feeder (4). Under the low temperature environment of the cooling water of the outer tube of the ammonium chloride feed pipe (9), the ammonium chloride powder, together with the hydrogen chloride gas entering from the hydrogen chloride gas inlet pipe (10), falls into the fluidized bed of alumina powder in the ammonium chloride decomposition reactor (5), and is sublimated or decomposed into ammonium chloride gas by heating. It is mixed with the hydrogen chloride gas as the fluidizing medium and the ammonium chloride and hydrogen chloride mixed gas is obtained at the top of the ammonium chloride decomposition reactor (5) and discharged from the gas outlet pipe (11). d. Liquid methanol feedstock enters methanol vaporizer (1) through methanol feedstock pipe (7) for vaporization to obtain methanol saturated vapor, which then enters methanol superheater (2) for further heating to obtain methanol superheated vapor, and then enters chloromethane synthesis reactor; for fluidized bed synthesis reactor (6) process, methanol superheated vapor enters the bottom of fluidized bed synthesis reactor (6) and mixes with high-temperature hydrogen chloride gas from hydrogen chloride heater (3) to obtain methanol hydrogen chloride mixed gas, which enters fluidized bed synthesis reactor (6) through gas distributor (22); for tubular fixed bed reactor (26) process, methanol superheated vapor enters from the top of tubular fixed bed reactor (26) and mixes with high-temperature hydrogen chloride gas from hydrogen chloride heater (3) to obtain methanol hydrogen chloride mixed gas, which enters tubular fixed bed reactor (26); e. The ammonium chloride and hydrogen chloride mixed gas exiting from the gas outlet pipe (11) enters the fluidized bed synthesis reactor (6) or the tubular fixed bed reactor (26); for the fluidized bed synthesis reactor (6) process, the ammonium chloride and hydrogen chloride mixed gas enters the fluidized bed synthesis reactor (6) through the inlet pipe (12), and together with the methanol and hydrogen chloride mixed gas entering from the bottom, enters the catalyst fluidized bed layer to fully contact and undergo the chloromethane synthesis reaction, obtaining a reaction product mixed gas containing chloromethane, ammonia, water vapor and a small amount of dimethyl ether and methylamine by-products; for the tubular fixed bed reactor (26) process, the ammonium chloride and hydrogen chloride mixed gas enters the upper part of the tubular fixed bed reactor (26) through the tubular fixed bed reactor inlet pipe (30), and together with the methanol and hydrogen chloride mixed gas, enters the tube side containing catalyst particles to fully contact and undergo the chloromethane synthesis reaction, obtaining a reaction product mixed gas containing chloromethane, ammonia, water vapor and a small amount of dimethyl ether and methylamine by-products; f. The reaction product mixed gas enters the separation process from the top of the fluidized bed synthesis reactor (6) via the product gas pipe (13) to obtain chloromethane and liquid ammonia products; or, the reaction product mixed gas enters the separation process from the bottom of the tubular fixed bed reactor (26) via the tubular fixed bed reactor product gas pipe (27) to obtain chloromethane and liquid ammonia products.

3. The method for producing chloromethane according to claim 2, characterized in that, The outlet temperature of the hydrogen chloride gas in the hydrogen chloride heater (3) is 220~300℃, and the operating pressure is 0.05~0.2MPa; the outlet temperature of the methanol superheater (2) is 150~250℃, and the operating pressure is 0.05~0.2MPa; the operating temperature of the ammonium chloride decomposition reactor (5) is 320~400℃, the operating pressure is 0.05~0.2MPa, and the empty tower gas velocity of hydrogen chloride gas is 0.1~0.5m / s; the closed ammonium chloride feeder (4) is protected by nitrogen replacement, and the pressure is maintained at 0.06~0.22MPa.

4. The method for producing chloromethane according to claim 2, characterized in that, The fluidized bed synthesis reactor (6) operates at a temperature of 300~380℃, an operating pressure of 0.05~0.2MPa, and a standard space velocity of 200~1000h-1; the tubular fixed bed reactor (26) operates at a temperature of 300~360℃, an operating pressure of 0.05~0.2MPa, and a standard space velocity of 200~800h-1.

5. The method for producing chloromethane according to claim 2, characterized in that, The pipelines entering the fluidized bed synthesis reactor (6) or the tubular fixed bed reactor (26) need to be insulated. The pipeline insulation temperature of the ammonium chloride and hydrogen chloride mixed gas is 310~390℃; the pipeline insulation temperature of the methanol superheated steam and the hydrogen chloride high temperature gas is 200~250℃.

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