A kind of acetylene process for synthesizing vinyl chloride

Abstract

The present invention relates to a vinyl chloride synthesis reaction process, and in particular to an acetylene method vinyl chloride synthesis reaction process, comprising: (1) a mixed raw material gas A is subjected to an adiabatic catalytic reaction to obtain a mixed gas B; (2) the mixed gas B is subjected to an isothermal catalytic reaction to obtain a mixed gas C containing vinyl chloride, and the mixed gas C enters a post-processing system. The present invention adopts radial and two-stage catalytic reactions, eliminates a separate raw material gas preheater, reduces the number of equipment, saves equipment investment, reduces reaction pressure drop, prolongs catalyst life, and improves subsequent reaction efficiency, so that the conversion rate is greater than 98.5% and the selectivity is greater than 99%.

Description

Technical Field

[0001] The invention relates to a vinyl chloride synthesis reaction process, in particular to a radial adiabatic isothermal reaction process for synthesizing vinyl chloride by an acetylene process. Background Art

[0002] Vinyl chloride monomer is the raw material for the polymerization reaction of polyvinyl chloride. In the process of producing polyvinyl chloride by the calcium carbide method, the acetylene gas sent from the acetylene device is cooled to about 1-5°C by the flame arrester and precooler, and mixed with the hydrogen chloride gas sent from the hydrogen chloride device at a molecular ratio of 1:1.05-1.1. The mixed gas is cooled and dehydrated and then heated to 70-90°C by the preheater. After meeting the activation temperature requirements, it is sent to the two-stage series vinyl chloride synthesis converter. Each stage of the converter can be operated in parallel by several units. The acetylene content in the outlet gas of the first stage converter is generally controlled at 20%-30%, and the acetylene content in the outlet gas of the second stage converter is generally controlled at 1%-3%. The generated crude vinyl chloride is purified, compressed, and distilled, and then sent to the subsequent process to produce polyvinyl chloride.

[0003] The equation for the heterogeneous reaction of acetylene and hydrogen chloride to synthesize vinyl chloride is as follows:

[0004] CHCH+HCl→CH2CHCl+124.8kJ / mol

[0005] Acetylene hydrochlorination is a typical highly exothermic reaction, releasing 124.8 kJ of energy per mole of reaction. The reaction temperature has a great influence on the vinyl chloride synthesis reaction. The increase in temperature is beneficial to the synthesis of vinyl chloride, but it will also cause the loss of active components of the catalyst and increase the formation of by-products such as dichloroethylene and dichloroethane. At the same time, different catalysts require different activation temperature requirements. For example, the activation temperature required for low-mercury catalysts is 70-90°C, and the activation temperature required for gold-based mercury-free catalysts is about 130°C.

[0006] In industry, separate heat exchangers are used to preheat acetylene and hydrogen chloride to ensure the required activation temperature of the catalyst. The vinyl chloride synthesis converter generally uses a fixed tube reactor with a reaction tube diameter of The length is about 3000mm. The catalyst is loaded in the tube, and the reaction gas passes through the catalyst bed axially from top to bottom. The heat released by the reaction is removed through the coolant in the shell side. The coolant is generally water or heptane, and the coolant and the reaction gas are countercurrently exchanged for heat.

[0007] There are obvious hot spots and axial temperature distribution in the existing vinyl chloride synthesis converter. In order to avoid excessive hot spot temperature causing catalyst sintering, loss of active components, shortened life, and increase of reaction by-products, the bed temperature in the converter except for the hot spot is kept in a relatively low range. Although the residence time is long, the synthesis efficiency in most of the space is low, which not only causes space waste, but also limits the reaction efficiency and processing capacity of a single converter.

[0008] In addition, the critical pressure of acetylene decomposition explosion is only 0.14MPa, so vinyl chloride synthesis must be operated at a relatively low pressure. Once the pressure drop increases significantly, it will not only increase the energy consumption of the system, but also increase the risk of acetylene compression explosion. Therefore, the existing shell-and-tube reactors not only have high requirements on the size and loading of the catalyst, but also the length of the tubes should not be too long. Due to the limitation of the aspect ratio, the diameter of the converter should not be too large, making it difficult to scale up the existing shell-and-tube reactors.

[0009] Patent document CN201611129302.4 discloses a reaction process for synthesizing vinyl chloride by acetylene method. The reactor for synthesizing vinyl chloride by acetylene method has good heat dissipation effect and corrosion resistance, high vinyl chloride synthesis efficiency and good effect by improving the structure of the reactor. It has a simple structure and is easy to install, which can further play its advantages in the reaction of synthesizing vinyl chloride by acetylene method in a fixed bed reactor. However, the use of mercury catalysts causes serious environmental pollution. If a mercury-free catalyst is to be used, the entire reactor needs to be kept at a higher temperature to meet the reaction temperature requirements, which can easily lead to catalyst deactivation.

[0010] Patent document 201810112960.5 discloses a non-mercury catalyst acetylene method vinyl chloride synthesis process, which is mixed, preheated and converted twice to obtain crude vinyl chloride. Although the concentration of acetylene gas introduced into the converter is increased, which is beneficial for vinyl chloride synthesis, promotes the increase of acetylene conversion rate and prolongs the service life of the catalyst, preheating is required during the reaction process, a large number of reactors are used, the reaction process is complicated, and the reaction cost is increased.

[0011] Based on the above problems existing in the prior art, it is necessary to design an acetylene-based vinyl chloride synthesis reaction process that can meet the vinyl chloride synthesis reaction temperature, avoid catalyst deactivation as much as possible, reduce the number of equipment, and effectively utilize system energy. However, it still faces many challenges. Summary of the invention

[0012] The present invention aims to provide a radial adiabatic isothermal reaction process, which can reduce the number of equipment, save equipment investment, and at the same time extend the life of the catalyst, improve the subsequent reaction efficiency, yield and selectivity of the acetylene method vinyl chloride synthesis reaction process.

[0013] To achieve the above object, the technical solution of the present invention is:

[0014] An acetylene-based vinyl chloride synthesis reaction process comprises the following steps:

[0015] (1) Mixing raw gas A undergoes an adiabatic catalytic reaction to obtain mixed gas B;

[0016] (2) The mixed gas B undergoes an isothermal catalytic reaction to obtain a mixed gas C containing vinyl chloride, and the mixed gas C enters the post-treatment system.

[0017] The mixed raw material gas A is a mixed gas of hydrogen chloride and acetylene.

[0018] In the preferred technical solution of the present invention, the mixed raw gas A in step (1) is a mixed gas of hydrogen chloride and acetylene that has been cryogenically dehydrated.

[0019] In a preferred technical solution of the present invention, the molar ratio of hydrogen chloride to acetylene in step (1) is 1.1:1.

[0020] In the preferred technical solution of the present invention, the volume space velocity of the raw material gas acetylene in step (1) is controlled to be 50-70h -1 , the raw gas pressure is 30-50kPag.

[0021] In the preferred technical solution of the present invention, the volume space velocity of the raw material gas acetylene in step (1) is controlled to be 60h -1 , the raw gas pressure is 40kPag.

[0022] In the preferred technical solution of the present invention, the outlet temperature of the adiabatic catalytic reaction in step (1) is 135°C.

[0023] In a preferred technical solution of the present invention, in the adiabatic catalytic reaction in step (1), the mixed raw gas A undergoes an adiabatic catalytic reaction radially from inside to outside.

[0024] In a preferred technical solution of the present invention, in the isothermal catalytic reaction in step (2), the mixed gas B undergoes an isothermal catalytic reaction radially from the outside to the inside.

[0025] In the preferred technical scheme of the present invention, the catalysts in step (1) and step (2) are both gold-based mercury-free catalysts, with coconut shell charcoal pretreated with hydrochloric acid as the carrier, AuCl3 as the active component, and one or more of potassium chloride, barium chloride, copper chloride, ruthenium trichloride, nickel chloride, and cobalt chloride as the auxiliary agent; wherein the mass content of Au is 0.1-0.2%, and the mass percentage of the auxiliary agent to the catalyst is 2-8%.

[0026] In a preferred technical solution of the present invention, during the isothermal catalytic reaction process in step (2), the reaction heat is removed through a shell-and-tube heat exchanger.

[0027] In the preferred technical solution of the present invention, a gas-liquid separator is further provided, and the circulating medium in the heat exchanger enters from the gas-liquid separator, and the heat exchange tube uses saturated water or heptane as the circulating medium.

[0028] In the preferred technical solution of the present invention, the temperature of the reaction bed in the isothermal reaction section during the reaction is 190°C, and the hot spot temperature does not exceed 195°C.

[0029] In the preferred technical solution of the present invention, the pressure of the gas-liquid separator connected to the reactor can be adjusted to achieve the adjustment and control of different reaction hotspots of the catalyst in the early and late stages of the reaction, and the operating pressure of the gas-liquid separator is controlled at 0.05-1.0 MPag.

[0030] In a preferred technical solution of the present invention, the gas distributor may be a mesh, perforated plate or strip grid structure.

[0031] In the preferred technical solution of the present invention, the concentrations of C2H2 and HCl in the raw gas just entering the isothermal section are relatively high, and the reaction of synthesizing vinyl chloride is violent. More heat exchange tubes can be arranged outside the reactor to remove more heat.

[0032] The hot spot temperature in the present invention refers to the temperature at the location where the reaction is most intense during the catalytic reaction.

[0033] The beneficial effects of the present invention are:

[0034] (1) The upper adiabatic reaction can increase the temperature of the reaction gas to meet the activation temperature requirement of the catalyst, thereby eliminating the need for a separate raw gas preheater, reducing the number of equipment, saving equipment investment, and improving the efficiency of subsequent reactions.

[0035] (2) The radial reaction is adopted in the isothermal reaction section, which increases the reaction flow area, increases the effective heat exchange area and heat transfer capacity in the reaction hot spot area, can better control the hot spot temperature, reduce the axial temperature gradient of the catalyst bed, and keep the entire catalyst bed in the optimal reaction temperature area, thereby reducing the generation of by-products and improving the conversion rate of acetylene hydrochlorination reaction, making the conversion rate greater than 98.5% and the selectivity greater than 99%, and avoiding the deactivation or shortening of the service life of the gold-based mercury-free catalyst due to overheating.

[0036] (3) A two-stage catalytic reaction method is used to realize product synthesis in one reactor, thereby reducing the number of reactors, avoiding waste of reactor space, improving the synthesis efficiency and processing capacity of a single device, and then realizing the conversion of the existing two-stage reaction into a one-stage synthesis reaction.

[0037] (4) Both adiabatic catalytic reaction and isothermal catalytic reaction adopt radial reaction, which shortens the reaction gas path and increases the reaction flow area. Compared with axial reaction, the reaction pressure drop can be further reduced, thereby reducing the energy loss of the system and facilitating the large-scale equipment.

[0038] (5) In the acetylene-based vinyl chloride synthesis reaction process of the present invention, the volume space velocity of acetylene can reach 50-70h -1 , shortening the reaction time. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Attached Figure 1 It is a schematic diagram of the reactor structure of the present invention.

[0040] Attached Figure 2 This is the radial adiabatic isothermal reactor system described in the present invention.

[0041] Attached Figure 3 This is the process flow described in the comparative example.

[0042] Attached Figure 1 In the figure: 1 is an upper head, 2 is a shell, 3 is a lower head, 4 is a central gas distribution pipe, 5 is an adiabatic reaction section and a catalytic reaction section, 6 is a catalyst pressure plate, 7 is a support plate, 8 is a heat exchange tube, 9 is a central gas collecting pipe, 10 is an upper tube plate, 11 is a lower tube plate, 12 is an air chamber, 13 is a water chamber, 14 is a catalyst discharge port, 15 is a baffle, 16 is a gas distributor, 17 is a circulating medium inlet, 18 is a circulating medium outlet, 19 is a gas channel, 20 is a small hole 1, 21 is a small hole 2, 22 is a small hole 3, and 23 is a small hole 4.

[0043] Attached Figure 2 In the figure: E1 is a mixer, E2 is a cooler, E3 is a demister, E4 is a reactor, and E5 is a gas-liquid separator.

[0044] Attached Figure 3 In the figure: E11 is a mixer, E12 is a cooler, E13 is a demister, E14 is a mixed raw gas preheater, E15-1 is a primary synthesis reactor, E15-2 is a secondary synthesis reactor, and E16 is a hot water tank.

[0045] The present invention will be further described with reference to the accompanying drawings and embodiments: DETAILED DESCRIPTION

[0046] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described with reference to the accompanying drawings:

[0047] The raw gas of the present invention enters the catalyst adiabatic reaction section from the central gas distribution pipe at the upper part of the reactor, enters the catalyst bed through the gas distributor, performs adiabatic catalytic reaction in radial direction, then enters the isothermal catalytic reaction section through the gas channel, enters the catalyst bed through the opening on the shell, performs isothermal catalytic reaction in radial direction, and finally enters the central gas collecting pipe to exit the reactor. The circulating medium enters the water chamber at the bottom of the reactor from the gas-liquid separator, enters the catalyst bed along the heat exchange pipe, enters the gas chamber after absorbing heat and vaporizing, and returns to the gas-liquid separator.

[0048] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0049] Example 1

[0050] As attached Figure 1 As shown, a vinyl chloride synthesis system using a radial adiabatic isothermal reactor in parallel, including a radial adiabatic isothermal reactor and a gas-liquid separator. Reactor E4 is an acetylene-based vinyl chloride synthesis reactor, including an upper head 1, a shell 2 and a lower head 3 from top to bottom, characterized in that the shell 2 includes an upper section, an air chamber 12, a lower section and a water chamber 13 from top to bottom.

[0051] The upper section includes a central gas distribution pipe 4, a catalyst pressure plate 6, an adiabatic catalytic reaction section 5 and a support plate 7. The central gas distribution pipe 4 is arranged in the middle of the upper section, the upper end is arranged outside the upper head 1, and the lower end is connected to the support plate 7. The adiabatic catalytic reaction section 5 is between the catalyst pressure plate 6 and the support plate 7. The lower section includes a heat exchange tube 8, a central gas collecting pipe 23, an upper tube sheet 10, and a lower tube sheet 11. The lower tube sheet 11 is built into the lower part of the shell 2. The upper tube sheet 10 is arranged above the lower tube sheet 11. The central gas collecting pipe 9 is arranged in the middle of the lower section, the upper end is connected to the upper tube sheet 10, and the lower end is arranged outside the lower head 3. The heat exchange tubes 8 are radially arranged on the lower tube sheet. A catalyst discharge port 14 is provided on the right side of the lower head 3.

[0052] The portion between the catalyst platen 6 and the support plate 7 of the central gas distribution pipe 4 is provided with a small hole 20. A baffle 15 is also provided inside the shell 2, and the baffle 15 has a small hole 21 in the portion between the catalyst platen 6 and the support plate 7, and a small hole 22 in the portion between the upper tube plate 10 and the lower tube plate 11. The central gas collecting pipe 9 has a small hole 23 in the portion between the upper tube plate 10 and the lower tube plate 11. A gas distributor 16 is also provided on the support plate 7, and the gas distributor 16 is a mesh, perforated plate or strip grid structure. There is a gas channel 19 between the shell 2 and the baffle 15, and the upper section and the lower section are connected through the gas channel 19. The catalyst is loaded on the outside of the heat exchanger tube. The catalysts in the upper and lower sections are both gold-based mercury-free catalysts. The gold-based mercury-free catalyst uses coconut shell charcoal pretreated with hydrochloric acid as a carrier, AuCl3 as an active component, and one or more of potassium chloride, barium chloride, copper chloride, ruthenium trichloride, nickel chloride, and cobalt chloride as an auxiliary agent; wherein the mass content of Au is 0.1-0.2%, and the mass percentage of the auxiliary agent to the catalyst is 2-8%. A circulating medium inlet 17 is provided on the left side of the lower head, and a circulating medium outlet 18 is provided on the left side of the shell 2, and the circulating medium outlet 18 is connected to the gas chamber 12.

[0053] As attached Figure 2 As shown, the process flow of synthesizing vinyl chloride by the calcium carbide method matched with the radial adiabatic isothermal reactor for synthesizing vinyl chloride of the present invention is shown. After the raw gas hydrogen chloride and acetylene are mixed in a molar ratio of 1.1:1 in the mixer E1, the mixed raw gas is cooled to -14°C by the mixed gas cooler E2, and then the hydrochloric acid mist in the mixed gas is removed by the demister E3. After that, the mixed gas enters the reactor from the top of the radial reactor E4, and enters the adiabatic catalytic reaction section through the central gas distribution pipe. Part of the hydrogen chloride and acetylene react adiabatically, so that the raw gas temperature is increased to 135°C, and then enters the isothermal catalytic reaction section through the gas channel and gas distributor outside the cylinder, and then enters the catalyst bed through the opening on the shell, and performs isothermal catalytic reaction in the radial direction. The air velocity of the raw gas acetylene entering the central gas distribution pipe is controlled to be 60h -1, the raw gas pressure is 40kPag. The mixed raw gas undergoes catalytic reaction in the radial direction, and finally enters the central gas collecting pipe and exits the reactor from the bottom of the reactor. The adiabatic section and the isothermal section are both filled with gold-based mercury-free catalysts. The catalyst uses coconut shell activated carbon as a carrier, the Au content is 0.1%, AuCl3 as an active component, potassium chloride and ruthenium trichloride as additives, and the contents of potassium chloride and ruthenium chloride are 0.5% and 1%, respectively. The catalyst in the isothermal catalytic reaction section is loaded on the shell side, and saturated water is used as the circulating medium in the heat exchange tube to remove the reaction heat by evaporation of saturated water. The circulating medium enters the water chamber at the bottom of the reactor from the gas-liquid separator, enters the catalyst bed along the heat exchange tube, enters the gas chamber after absorbing heat and vaporizing, and returns to the gas-liquid separator. The pressure of the gas-liquid separator E5 is controlled to 0.3MPag. During operation, the reaction bed temperature is 190℃, and the hot spot temperature does not exceed 195℃. The acetylene conversion rate at the outlet of the radial adiabatic isothermal reactor is 98.8%, and the selectivity is 99.2%. The reacted gas is sent to the post-processing system.

[0054] Example 2

[0055] The raw gas hydrogen chloride and acetylene are mixed in the mixer E1 at a molar ratio of 1.1:1, and then the mixed raw gas is cooled to -14°C by the mixed gas cooler E2, and then the hydrochloric acid mist in the mixed gas is removed by the demister E3, and then enters the reactor from the top of the radial reactor E4, and enters the adiabatic catalytic reaction section through the central gas distribution pipe. Part of the hydrogen chloride and acetylene react adiabatically, so that the raw gas temperature is raised to 135°C, and then enters the isothermal catalytic reaction section through the gas channel and gas distributor on the outside of the cylinder, and then enters the catalyst bed through the opening on the shell, and performs isothermal catalytic reaction in the radial direction. The air velocity of the raw gas acetylene entering the central gas distribution pipe is controlled to 50h -1 , the raw gas pressure is 40kPag. The mixed raw gas undergoes catalytic reaction in the radial direction, and finally enters the central gas collecting pipe and exits the reactor from the bottom of the reactor. The adiabatic section and the isothermal section are both filled with gold-based mercury-free catalysts. The catalyst uses coconut shell activated carbon as a carrier, the Au content is 0.1%, AuCl3 as an active component, potassium chloride and ruthenium trichloride as additives, and the contents of potassium chloride and ruthenium chloride are 0.5% and 1%, respectively. The catalyst in the isothermal catalytic reaction section is loaded on the shell side, and saturated water is used as the circulating medium in the heat exchange tube, and the reaction heat is removed by evaporation of saturated water. The circulating medium enters the water chamber at the bottom of the reactor from the gas-liquid separator, enters the catalyst bed along the heat exchange tube, enters the gas chamber after absorbing heat and vaporizing, and returns to the gas-liquid separator. The pressure of the gas-liquid separator E5 is controlled to 0.3MPag. During operation, the reaction bed temperature is 190℃, and the hot spot temperature does not exceed 195℃. The acetylene conversion rate at the outlet of the radial adiabatic isothermal reactor is 99.1%, and the selectivity is 99.2%. The reacted gas is sent to the post-processing system.

[0056] Example 3

[0057] The raw gas hydrogen chloride and acetylene are mixed in the mixer E1 at a molar ratio of 1.1:1, and then the mixed raw gas is cooled to -14°C by the mixed gas cooler E2, and then the hydrochloric acid mist in the mixed gas is removed by the demister E3, and then enters the reactor from the top of the radial reactor E4, and enters the adiabatic catalytic reaction section through the central gas distribution pipe. Part of the hydrogen chloride and acetylene react adiabatically, so that the raw gas temperature is raised to 135°C, and then enters the isothermal catalytic reaction section through the gas channel and gas distributor on the outside of the cylinder, and then enters the catalyst bed through the opening on the shell, and performs isothermal catalytic reaction in the radial direction. The air velocity of the raw gas acetylene entering the central gas distribution pipe is controlled to 70h -1 , the raw gas pressure is 40kPag. The mixed raw gas undergoes catalytic reaction in the radial direction, and finally enters the central gas collecting pipe and exits the reactor from the bottom of the reactor. The adiabatic section and the isothermal section are both filled with gold-based mercury-free catalysts. The catalyst uses coconut shell activated carbon as a carrier, the Au content is 0.1%, AuCl3 as an active component, potassium chloride and ruthenium trichloride as additives, and the contents of potassium chloride and ruthenium chloride are 0.5% and 2%, respectively. The catalyst in the isothermal catalytic reaction section is loaded on the shell side, and saturated water is used as the circulating medium in the heat exchange tube to remove the reaction heat by evaporation of saturated water. The circulating medium enters the water chamber at the bottom of the reactor from the gas-liquid separator bag, enters the catalyst bed along the heat exchange tube, enters the gas chamber after absorbing heat and vaporizing, and returns to the gas-liquid separator. The pressure of the gas-liquid separator E5 is controlled to 0.3MPag. During operation, the reaction bed temperature is 190℃, and the hot spot temperature does not exceed 195℃. The acetylene conversion rate at the outlet of the radial adiabatic isothermal reactor is 98.6%, and the selectivity is 99.1%. The reacted gas is sent to the post-processing system.

[0058] Comparative Example 1

[0059] The comparative example adopts a vinyl chloride synthesis converter commonly used in the industry, which includes a reactor shell and a tube array. The raw gas enters the tube side through the raw gas inlet at the top of the primary reactor, and the inside of the tube array is filled with an old low-mercury catalyst. The catalyst uses coal-based activated carbon as a carrier, HgCl2 as an active component, and the HgCl2 content is 4%. The product gas and the unreacted raw gas leave the primary reactor from the lower part of the reactor. Then it enters the secondary reactor to continue the reaction, and the inside of the secondary reactor tube is filled with a fresh low-mercury catalyst. The circulating hot water enters the reactor shell from the lower part of the converter, and returns to the hot water tank from the upper part after heat exchange. The upper water temperature of the circulating hot water is 96°C.

[0060] The raw gas hydrogen chloride and acetylene are mixed in a mixer E11 at a molar ratio of 1.1:1, cooled to -14°C by the mixed gas cooler E12, and then sent to the mixed raw gas preheater E14 to be preheated to 90°C after the hydrochloric acid mist in the mixed gas is removed by the demister E13. Then, the mixed gas enters the primary synthesis reactor E15-1. The space velocity of the raw gas acetylene is controlled to 35h-1 , the raw gas pressure is 40kPag. During operation, the reaction bed temperature of the primary synthesis reactor is 110°C, the hot spot temperature does not exceed 150°C, and the acetylene conversion rate at the outlet of the primary synthesis reactor is greater than 70%. The reaction gas at the outlet of the primary synthesis reactor then enters the secondary synthesis reactor E15-2 in series, the reaction bed temperature is 100°C, and the hot spot temperature does not exceed 140°C. The reaction heat in the two-stage series synthesis reactor is removed through the 96°C circulating hot water in the hot water tank E16. The acetylene conversion rate at the outlet of the secondary reactor is 96.8%. The reacted gas is sent to the post-processing system.

[0061] The above description is only an illustrative specific implementation mode of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any technician in the field without departing from the concept and principle of the present invention should fall within the scope of protection of the present invention. It should also be noted that the various components of the present invention are not limited to the above-mentioned overall application. The various technical features described in the specification of the present invention can be selected one by one or multiple ones can be selected and used in combination according to actual needs. Therefore, the present invention should naturally cover other combinations and specific applications related to the innovative points of this case.

Claims

1. An acetylene-based vinyl chloride synthesis reaction process, characterized in that: The following steps are involved: (1) Mixing raw gas A undergoes an adiabatic catalytic reaction to obtain mixed gas B; (2) Mixed gas B undergoes an isothermal catalytic reaction to obtain mixed gas C containing vinyl chloride, and mixed gas C enters a post-treatment system; The mixed raw gas A is a mixed gas of hydrogen chloride and acetylene; The synthesis reaction process is carried out in a vinyl chloride synthesis system of a radial adiabatic isothermal reactor connected in parallel, comprising a radial adiabatic isothermal reactor and a gas-liquid separator. The reactor (E4) is an acetylene-based vinyl chloride synthesis reactor, comprising, from top to bottom, an upper head (1), a shell (2) and a lower head (3), characterized in that: the shell (2) comprises, from top to bottom, an upper section, an air chamber (12), a lower section and a water chamber (13), The upper section comprises a central gas distribution pipe (4), a catalyst pressure plate (6), an insulated catalytic reaction section (5) and a support plate (7); the central gas distribution pipe (4) is arranged in the middle of the upper section, the upper end is arranged outside the upper end cap (1), and the lower end is connected to the support plate (7); the insulated catalytic reaction section (5) is between the catalyst pressure plate (6) and the support plate (7); the lower section comprises a heat exchange tube (8), a central gas collecting pipe (9), an upper tube plate (10), and a lower tube plate (11); the lower tube plate (11) is built into the lower part of the shell (2); the upper tube plate (10) is arranged above the lower tube plate (11); the central gas collecting pipe (9) is arranged in the middle of the lower section, the upper end is connected to the upper tube plate (10), and the lower end is arranged outside the lower end cap (3); the heat exchange tube (8) is radially arranged on the lower tube plate, and a catalyst discharge port (14) is provided on the right side of the lower end cap (3); The portion of the central gas distribution pipe (4) between the catalyst pressure plate (6) and the support plate (7) is provided with a small hole 1 (20); the shell (2) is further provided with a baffle (15); the portion of the baffle (15) between the catalyst pressure plate (6) and the support plate (7) is provided with a small hole 2 (21); the portion of the baffle (15) between the upper tube plate (10) and the lower tube plate (11) is provided with a small hole 3 (22); the portion of the central gas collecting pipe (9) between the upper tube plate (10) and the lower tube plate (11) is provided with a small hole (23); the support plate (7) is further provided with a gas distributor (16); the gas distributor (16) is a mesh, perforated plate or strip grid structure; the shell (2) and the baffle (15) are provided with a small hole 2 (21); the portion of the baffle (15) between the catalyst pressure plate (6) and the support plate (7) is provided with a small hole 3 (22); the portion of the central gas collecting pipe (9) between the upper tube plate (10) and the lower tube plate (11) is provided with a small hole 23; The heat exchanger is a gas channel (19), wherein the upper section and the lower section are connected via the gas channel (19), and the catalyst is loaded outside the heat exchanger tube. The catalysts in the upper section and the lower section are both gold-based mercury-free catalysts. The gold-based mercury-free catalyst uses coconut shell charcoal pretreated with hydrochloric acid as a carrier, AuCl3 as an active component, and one or more of potassium chloride, barium chloride, copper chloride, ruthenium trichloride, nickel chloride, and cobalt chloride as an auxiliary agent; wherein the mass content of Au is 0.1-0.2%, and the mass percentage of the auxiliary agent to the catalyst is 2-8%. A circulating medium inlet (17) is provided on the left side of the lower end cap, and a circulating medium outlet (18) is provided on the left side of the shell (2), and the circulating medium outlet (18) is connected to the gas chamber (12).

2. The reaction process according to claim 1, characterized in that: The mixed raw material gas A is a mixed gas of hydrogen chloride and acetylene that has been cryogenically dehydrated, wherein the molar ratio of hydrogen chloride to acetylene is 1.1:

1.

3. The reaction process according to claim 1, characterized in that: The volume space velocity of the raw gas acetylene in step (1) is controlled to be 50-70h -1 , the raw gas pressure is 30-50kPag.

4. The reaction process according to claim 3, characterized in that: The volume space velocity of the raw gas acetylene in step (1) is controlled to be 60h -1 , the raw gas pressure is 40kPag.

5. The reaction process according to claim 1, characterized in that: The outlet temperature of the adiabatic catalytic reaction in step (1) is 135°C.

6. The reaction process according to claim 1, characterized in that: In the adiabatic catalytic reaction of step (1), the mixed raw gas A undergoes an adiabatic catalytic reaction radially from the inside to the outside. In the isothermal catalytic reaction of step (2), the mixed gas B undergoes an isothermal catalytic reaction radially from the outside to the inside.

7. The reaction process according to claim 6, characterized in that: During the isothermal catalytic reaction in step (2), the reaction heat is removed through a shell-and-tube heat exchanger.

8. The reaction process according to claim 7, characterized in that: A gas-liquid separator is also provided, and the circulating medium in the heat exchanger enters from the gas-liquid separator, and the heat exchange tube uses saturated water or heptane as the circulating medium.

9. The reaction process according to claim 8, characterized in that: The gas-liquid separator pressure is controlled to be 0.05-1.0 MPag.

10. The reaction process according to claim 9, characterized in that: During the reaction process, the temperature of the reaction bed in the isothermal reaction section is 190°C, and the hot spot temperature does not exceed 195°C.

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