Method and device for producing vinyl chloride from 1, 2-dichloroethane

Abstract

The invention relates to a method for producing vinyl chloride by catalytic thermal cracking of 1, 2-dichloroethane, the heat required for the thermal cracking being supplied via a liquid or condensing heat transfer medium (4), the heat transfer medium (4) being heated at least partially by thermal energy obtained when hydrogen (10), ammonia (11) or a hydrogen-ammonia mixture is oxidized according to the invention. The invention also relates to a device for producing vinyl chloride by catalytic thermal cracking of 1, 2-dichloroethane, comprising at least one reactor (1) carrying out thermal cracking and at least one first heating device (6), by means of which a reaction medium (13) in the reactor (1) is heated by a heat transfer medium (4), wherein the at least one first heating device (6) is designed to oxidize hydrogen gas (10) and / or ammonia (11), for example to burn hydrogen gas (10) and / or ammonia (11), in order to generate thermal energy, by means of which the heat transfer medium (4) can be heated.

Description

[0001] The present invention relates to a method for producing vinyl chloride by catalytic thermal cracking of 1,2-dichloroethane, wherein the heat required for thermal cracking is supplied via a liquid heat transfer medium or a condensing heat transfer medium. The present invention also provides a plant for producing vinyl chloride by catalytic thermal cracking of 1,2-dichloroethane, wherein the heat required for thermal cracking is supplied via a liquid heat transfer medium or a condensing heat transfer medium, the plant comprising at least one reactor for thermal cracking, at least one first heating device and a conduit system for supplying a heated heat transfer medium (4) to the reactor (1), the heat transfer medium being heated by means of the first heating device. The at least one first heating device is operated by a fuel that burns without forming carbon dioxide, and the fuel is preferably hydrogen or ammonia or a mixture of hydrogen and ammonia, more preferably hydrogen, i.e. the heat transfer medium is heated in the at least one first heating device by the heat energy generated by the oxidation of hydrogen or another fuel that burns without forming carbon dioxide.

[0002] The thermal cracking of 1,2-dichloroethane to produce vinyl chloride, which is particularly desirable for the production of polyvinyl chloride, follows the reaction equation shown below:

[0003] C2H4Cl2→C2H3Cl+HCl(1)

[0004] This is an endothermic reaction, where pyrolysis can be carried out in the gas phase without a catalyst at high pressures of 1 MPa to 3 MPa and temperatures of 450°C to 600°C, or in a catalytic process that allows pyrolysis to proceed at lower temperatures. Prior art

[0005] For example, EP 0 264 065 A1 describes a process for producing vinyl chloride by catalyst-free thermal cracking of 1,2-dichloroethane, wherein the 1,2-dichloroethane is heated in a first container, then the 1,2-dichloroethane is transferred to a second container by evaporating the 1,2-dichloroethane at a lower pressure than in the first container without further heating, and the gaseous 1,2-dichloroethane is fed to a cracking furnace, where it is cracked into vinyl chloride and hydrogen chloride. The temperature of the 1,2-dichloroethane when leaving the second container is 220° C. to 280° C. In the cracking furnace, the tubes in which the 1,2-dichloroethane undergoes thermal cracking are heated by means of fossil fuels. In the radiant zone of the cracking furnace, the gaseous 1,2-dichloroethane is heated to 525° C. and 533° C., respectively.

[0006] EP 0 264 065 A1 also mentions that, for preheating the liquid, fresh 1,2-dichloroethane, a temperature regulating medium can be used, which in turn is heated in the convection zone of the cracking furnace by the flue gases produced by the burners that heat the cracking furnace. Heated high-boiling liquids, such as mineral oil, silicone oil or molten biphenyl, are suitable as temperature regulating media. However, this only enables preheating to a temperature of 150° C. to 220° C., while the pyrolysis itself is carried out at a temperature of about 530° C. This known method therefore does not allow the pyrolysis to be carried out in the temperature range of 200-400° C., nor can all the heating be carried out with the aid of a liquid heat transfer medium, which is necessary here.

[0007] The plant complex for the production of vinyl chloride usually consists of:

[0008] - a plant for the production of 1,2-dichloroethane from ethylene and chlorine ("direct chlorination"), or

[0009] - plants for the production of 1,2-dichloroethane from ethylene, hydrogen chloride and oxygen ("oxychlorination"),

[0010] - an apparatus for the distillative purification of 1,2-dichloroethane,

[0011] - a plant for the thermal cracking of 1,2-dichloroethane purified by distillation into vinyl chloride and hydrogen chloride, and

[0012] - Apparatus for distillative removal of hydrogen chloride and unreacted 1,2-dichloroethane and for purification of vinyl chloride.

[0013] The hydrogen chloride obtained by thermal cracking of 1,2-dichloroethane can be returned to the oxychlorination unit, where it can be reacted again with ethylene and oxygen to form 1,2-dichloroethane.

[0014] The above-mentioned plant complex can additionally include a plant for incinerating liquid and / or gaseous chlorinated hydrocarbons. These are produced as by-products in the production of vinyl chloride and are primarily removed during the distillative purification of 1,2-dichloroethane. The hydrogen chloride formed during the incineration of these substances is either supplied to other production processes as aqueous hydrochloric acid or likewise returned to the oxychlorination plant. The waste heat from the incineration is used in the existing steam generation process.

[0015] In the process for cracking 1,2-dichloroethane to vinyl chloride and hydrogen chloride described in DE 102 52 891 A1, a catalyst is used which is able to reduce the operating temperature in the endothermic cracking. However, in this process, the tubular reactor is also fired by a primary energy carrier (e.g. oil or gas), and the furnace is divided into a radiant zone and a convection zone. In the radiant zone, the heat required for the pyrolysis is transferred to the reaction tubes mainly by radiation from the burner-heated furnace walls. In the convection zone, the energy content of the hot flue gases leaving the radiant zone is utilized by convective heat transfer, resulting in that 1,2-dichloroethane can be preheated, vaporized or superheated as a reactant in the pyrolysis reaction.

[0016] Various measures for energy saving and / or heat recovery in plants for producing 1,2-dichloroethane are known in the prior art. These measures lead to a significant reduction in operating costs, thereby significantly improving the economic efficiency of the plant and reducing the CO2 emissions of the plant. These measures are, for example, the use of the reaction heat of the exothermic reaction step to heat the radiator in the process. WO 2014 / 108159 A1 details various known measures for heat recovery in plants for producing vinyl chloride, citing the corresponding references.

[0017] EP 0 225 617 A1 describes a process for producing vinyl chloride by thermal cracking of 1,2-dichloroethane, wherein it is mentioned that the process is carried out in some cases so that waste heat from the flue gases of the fired cracking furnace is recovered via the production of steam. However, the relatively low flue gas temperatures mean that this approach is not very economical. In this process, the thermal cracking of 1,2-dichloroethane also takes place at relatively high temperatures. First, the reactants are preheated to about 243° C., then evaporated partly by pressure release and partly by pressurization with steam, and then thermally cracked in a cracking furnace at temperatures between 435° C. and 497° C. without the use of a catalyst. Heating by means of thermal oil is not described and is also not possible at these temperatures.

[0018] EP 0 002 021 A1 describes a process for the catalytic dehydrohalogenation of 1,2-dichloroethane to vinyl chloride using a Lewis acid-treated zeolite catalyst. When such a catalyst is used, the reaction can be carried out at high temperatures and pressures in the range of 200° C. to 400° C., thus at significantly lower temperatures than the conventional pyrolysis of 1,2-dichloroethane.

[0019] It is an object of the present invention to provide an improved process for the production of vinyl chloride by thermal cracking of 1,2-dichloroethane, wherein a reduction in operating costs is achieved. Another object of the present invention is to improve the CO2 balance of a production process for the production of vinyl chloride.

[0020] This object is achieved by a process for producing vinyl chloride by catalytic thermal cracking of 1,2-dichloroethane having the properties mentioned at the outset and having the features of claim 1 .

[0021] According to the invention, the liquid or condensed heat transfer medium is heated at least temporarily, at least partially, by the heat energy generated in the oxidation of hydrogen, ammonia or ammonia-hydrogen mixtures. This mode of operation is CO2-neutral. The use of a catalyst for the thermal cracking of 1,2-dichloroethane makes it possible to shift the temperature range in which the reaction is fully carried out to lower temperatures, more particularly to a range of about 200° C. to about 400° C., so that the reactor can be heated by means of a heat transfer medium instead of directly firing the fossil fuels used in the prior art. As an alternative to a tubular cracking furnace, a shell and tube heat exchanger can be used as a reactor, for example, in which the tubes are filled with a catalyst bed and the heat transfer medium preferably flows through the shell space in a loop.

[0022] According to a preferred development of the process according to the invention, at least some or all of the hydrogen to be oxidized is produced in an upstream electrolysis unit. The electrolysis unit can preferably be configured to carry out chlor-alkali electrolysis. The chlorine produced can be used for direct chlorination purposes in a vinyl chloride production process. Alternatively, the electrolysis unit can also be configured for water electrolysis. In this case, the oxygen produced can be used for oxychlorination. Finally, the electrolysis unit can also be configured for hydrogen chloride electrolysis. Preferably, the hydrogen chloride produced in the thermal cracking of 1,2-dichloroethane undergoes electrochemical cracking and / or the chlorine formed is reused in the production process for the chlorination of ethylene.

[0023] Furthermore, it is advantageous that the heat required for the reaction is at least temporarily partially obtained by heating the heat transfer medium by combustion of hydrogen and / or ammonia.Here, the heat required for the reaction can be obtained completely by oxidation of hydrogen and / or ammonia.

[0024] The heat transfer medium can also be heated at least temporarily in part by means of heat energy generated by oxidation of hydrogen and / or ammonia, and in part by means of combustion of a fuel different from these fuels. In this preferred variant of the method, the heat required for the reaction is provided primarily via a first heating device heatable by means of hydrogen and / or ammonia, but at least one second heating device operating by means of a fuel different from the above-mentioned fuels is provided and can be used at least temporarily. In these cases, the first heating device can be throttled or, if necessary, completely shut down for a period of time, or the heat transfer medium is guided in such a way that its flow bypasses the first heating device.

[0025] For example, the at least one second heating device can be designed as an incineration device for incinerating liquid and / or gaseous chlorinated hydrocarbons, such as those produced as by-products in a vinyl chloride production plant.

[0026] The use of a liquid heat transfer medium or a condensed heat transfer medium to provide all the reaction heat required for the pyrolytic cracking of 1,2-dichloroethane can be achieved by carrying out the reaction in the presence of a suitable catalyst, which allows a significant reduction in the reaction temperature compared to conventional methods without catalysis. When such a catalyst is used, the reaction temperature can be reduced, for example, from a temperature magnitude of about 430°C to about 530°C, which is typical in conventional methods, to a temperature of in particular about 200°C to 400°C. Heating to a temperature within this range is possible, for example, when using a thermal oil or optionally a molten salt. Suitable catalysts include, for example, those described in EP 0 002 021 A1 mentioned above.

[0027] The process for purely thermal (uncatalyzed in a pyrolysis furnace) or thermocatalytic EDC cracking (supply of heat and use of a catalyst) generally consists of the following sub-steps:

[0028] -Preheat liquid 1,2-dichloroethane to its evaporation temperature at a given pressure,

[0029] - Evaporation of preheated 1,2-dichloroethane,

[0030] - optionally superheating the 1,2-dichloroethane vapor to the reaction temperature range (if the previous evaporation did not take place within the reaction temperature range),

[0031] - The cracking reaction is carried out with the supply of heat (pure thermal cracking or thermal cracking with the use of a catalyst).

[0032] The invention provides a method which, in addition to heating by means of a liquid heat transfer medium or a condensed heat transfer medium for catalytic thermal cracking reactions, can also be used for upstream preheating, vaporization or superheating of 1,2-dichloroethane by means of said heat transfer medium. Not all of these steps must be heated by means of a heat transfer medium. The method of the invention comprises heating at least one of the above-mentioned sub-steps to any desired combination, which in turn can be subdivided (with respect to the apparatus) into individual steps.

[0033] For the purposes of the process of the invention, "heating" means transferring heat to the starting material 1,2-dichloroethane and / or to the reaction mixture by means of a heat transfer medium. This can result in the starting material 1,2-dichloroethane being heated, evaporated and / or overheated. Heat can be supplied to the reaction mixture in the reactor at a constant temperature level (isothermal reaction control). The reaction mixture can also be further heated, wherein the heat supplied by heating is partly used to cover the heat demand of the reaction and partly used to further heat the reaction mixture. Finally, the heat supply to the reaction mixture by heating can be adjusted so that the appreciable heat of the reaction mixture is at least partly used to cover the heat demand of the reaction and the reaction mixture is cooled in the reactor compared to the reactor inlet temperature. The heating and the heat transfer to the starting material 1,2-dichloroethane are achieved by means of a liquid heat transfer medium accompanied by cooling of the heat transfer medium / reduction of its appreciable heat and / or by means of a condensed heat transfer medium that has previously been evaporated by a heating apparatus.

[0034] For the purposes of the method according to the invention, the devices (heaters and / or evaporators or devices combining the functions of heater and evaporator) that can be used for the heating device of the heat transfer medium are devices that can be heated by hydrogen, ammonia or an ammonia-hydrogen mixture (first heating device) or devices that can be heated by fossil fuels, such as thermal oil or preferably natural gas (second heating device). Alternatively, they can be heat transfer devices (heaters and / or evaporators or devices combining the functions of heater and evaporator) that are heated by waste heat from a device for incinerating by-products of a chemical plant, preferably from waste heat from a device for incinerating by-products of a complex of devices for the production of vinyl chloride. Such devices are known to those skilled in the art.

[0035] Typically, the heat requirement of a plant for the catalytic thermal cracking of 1,2-dichloroethane can only be partially met by incineration of by-products of the plant complex for the production of vinyl chloride. In a preferred operating mode, therefore, the heat transfer medium is initially heated by waste heat from the incineration of by-products, and the required remaining heat is supplied by combustion of hydrogen, ammonia or a hydrogen-ammonia mixture in the first heating unit.

[0036] According to a preferred improvement of the process according to the invention, a liquid heat transfer medium or a condensed heat transfer medium circulates in a circuit comprising at least one first heating device operated by oxidation of hydrogen, ammonia or a hydrogen-ammonia mixture and a reactor for catalytic thermal cracking of 1,2-dichloroethane, wherein heat exchange takes place between the reaction medium and the heat transfer medium in the reactor. The above-mentioned circuit preferably also comprises at least one second heating device operated by burning at least one fuel different from the fuels described above.

[0037] According to a preferred improvement of the method according to the invention, at least one first heating device and at least one second heating device are connected in series in the circuit. In this case, the heat transfer medium first flows through the second heating device in the conduit circuit and then flows through the first heating device located downstream thereof; alternatively, the flow through the two heating devices can occur in the opposite way. Alternatively, the two heating devices can also be arranged in a quasi-parallel connection, that is, the connection of the conduit circuit containing the heating devices is such that the relevant conduits can be closed (for example via valves) so that the heat transfer medium can flow through the second heating device without also flowing through the first heating device, or vice versa as required.

[0038] According to a preferred improvement of the inventive method, the heat transfer medium circulates in the loop in a countercurrent manner with the flow of the reaction medium through the reactor. This variant is advantageous for effective heat transfer. Alternatively, the flow of the heat transfer medium can be co-current with the flow of the reaction medium.

[0039] According to a preferred development of the method according to the invention, the second heating device is operated at least temporarily with the aid of waste heat from a plant for incinerating by-products of a vinyl chloride production plant. This variant has the advantage that the waste heat used comes essentially from plant elements within the same plant complex, which means that the energy balance of the process can be improved.

[0040] According to a preferred improvement of the method according to the invention, the second heating device is permanently operated at full load. The remaining energy required for thermal cracking can be supplied to the heat transfer medium by means of the first heating unit heated by hydrogen and / or ammonia. In this variant of the method, the second heating device is preferably permanently at operating temperature.

[0041] According to a preferred refinement of the process according to the invention, the thermal cracking of 1,2-dichloroethane is carried out in a temperature range of 200° C. to 400° C. This is a preferred temperature range which can be easily achieved with liquid heat transfer media, such as heat transfer oils.

[0042] The present invention also provides a device for producing vinyl chloride by catalytic thermal cracking of 1,2-dichloroethane, wherein the heat required for the thermal cracking of 1,2-dichloroethane and preferably the heat required for preheating, evaporation and / or superheating of 1,2-dichloroethane is supplied via a liquid heat transfer medium or a condensing heat transfer medium, the device comprising at least one reactor for thermal cracking, at least one first heating device and a conduit system for supplying the heated heat transfer medium to the reactor, the heat transfer medium being heated by means of the first heating device, wherein the at least one first heating device is designed for the oxidation of hydrogen and / or ammonia, i.e. it is capable of generating heat by oxidation of one of the above-mentioned fuels, preferably by combustion.

[0043] It is particularly preferred here when the device comprises at least one electrolysis unit upstream of the at least one first heating device, in particular for carrying out chlor-alkali electrolysis, water electrolysis or hydrogen chloride electrolysis, in which the hydrogen produced - optionally also after mixing with ammonia - is supplied to the at least one first heating device.

[0044] Furthermore, the device can comprise at least one second heating device for heating the reaction medium, which is designed to burn at least one fuel different from hydrogen and ammonia, for example methane, natural gas and / or liquid and / or gaseous waste from chemical plants. In this case, it is preferred that the heat transfer medium first flows through the second heating device. The residual heat required for cracking the 1,2-dichloroethane and for preheating the 1,2-dichloroethane to evaporate and / or superheat it can be supplied by the first heating unit. The first heating unit can preferably be designed to be adjustable in order to reach a predeterminable final temperature in the heat transfer medium.

[0045] In a preferred development of the invention, the conduit system forms a circuit of a heat transfer medium which comprises the reactor and at least one first heating device which is operated by means of hydrogen, ammonia or a hydrogen-ammonia mixture.

[0046] According to a preferred variant of the invention, the circuit of the heat transfer medium further comprises at least one second heating device. In this case, the flow sequence is preferably such that the medium first flows through the second heating device. Therefore, the term "first" or "second" heating device mentioned in this article only refers to the functionally different nature of the heating devices, and does not limit the order in which the heat transfer medium flows through them.

[0047] In a preferred development of the invention, the first heating device and the second heating device are arranged in series or optionally in parallel in a circuit of the heat transfer medium.

[0048] According to a preferred variant of the invention, means are provided for transferring heat from the heat transfer medium to the reaction medium flowing through the reactor or present in the reactor.

[0049] In a preferred development of the invention, the reactor comprises a shell and tube heat exchanger, the tubes of which are filled with the catalyst bed and which preferably has a shell space for the heat transfer medium circulating in the circuit to flow through.

[0050] The invention will be described in more detail below based on exemplary embodiments and with reference to the accompanying drawings, in which:

[0051] Figure 1 A schematically simplified plant diagram of a plant according to the invention for producing vinyl chloride by catalytic thermal cracking of 1,2-dichloroethane is shown, and

[0052] Figure 2 Shown is a schematic representation of a reactor comprising a shell and tube heat exchanger, the tubes of which are packed with a catalyst bed.

[0053] Reference is made below to the drawings, which serve to explain exemplary embodiment variants of the method according to the invention in more detail. Figure 1 and Figure 2 The description in the invention is schematically greatly simplified and only those plant components relevant to the context of the present invention are shown. The plant comprises a reactor 1, to which a reactor inlet stream 2 of 1,2-dichloroethane (EDC) is supplied, for example, via at least one conduit, and which is pyrolyzed in the reactor 1 under the influence of heat to monomeric vinyl chloride (VCM), the formation of which is accompanied by the production of hydrogen chloride. The product of the process mentioned leaves the reactor 1 in a reactor outlet stream 3.

[0054] The reactor 1 is integrated into a circuit 18 of a heat transfer medium 4 formed by a conduit system 8, so that heat is supplied to the reactor 1 via a liquid heat transfer medium (e.g. thermal oil), which preferably flows in countercurrent to the reaction medium in order to flow through the reactor 1 (see Figure 2 ) is heated to a temperature of, for example, 300° C. to 400° C., at which temperature catalytic thermal cracking of 1,2-dichloroethane to vinyl chloride occurs in reactor 1.

[0055] The circuit 18 of the heat transfer medium 4 is explained in more detail below. The circuit 18 of the heat transfer medium 4 comprises a pump 5 for circulating the heat transfer medium 4 in the circuit 18, wherein downstream of the pump 5 the heat transfer medium first flows through a second heating device 7, which is optional according to the teaching of the invention, wherein if the second heating device 7 is in operation, the heat transfer medium 4 can be heated by the combustion of at least one fuel different from hydrogen and / or ammonia (e.g. methane, natural gas and / or liquid and / or gaseous waste from a chemical plant) or by thermal energy from waste heat of a chemical plant (e.g. from a vinyl chloride production plant).

[0056] Downstream of the second heating device 7, the heat transfer medium 4 flows through the first heating device 6 which burns hydrogen 10, ammonia 11 or an ammonia-hydrogen mixture in order to heat the heat transfer medium 4. Figure 1 As shown, the hydrogen 10 used for heating can be generated, for example, in an upstream electrolysis unit 9. The electrolysis unit 9 can preferably be configured to carry out chlor-alkali electrolysis, water electrolysis or other hydrogen chloride electrolysis.

[0057] In the exemplary embodiment, the second heating device 7 and the first heating device 6 are arranged one after the other in the flow direction in the conduit system 8 of the circuit 18 and are therefore connected in series. Alternatively, the two heating devices can also be connected in parallel with each other, i.e. Figure 1 In contrast, both heating devices are integrated into the conduit system 8 , so that the heat transfer medium 4 can at least also flow through one or the other of the two heating devices while bypassing the other heating device.

[0058] exist Figure 1 In the variant shown, in which the two heating devices 6 and 7 are arranged in series, and in the variant with a parallel connection (not shown), it is possible to provide Figure 1 A valve, not shown, may be provided to switch the heating device on and off or to close the conduit in the circuit 18 at an appropriate position. In addition, one or more regulating devices (also not shown) may be provided. Figure 1 ), so as to adjust the heat output supplied by the first and / or second heating devices 6, 7 according to the heating requirements of the reaction medium in the reactor 1.

[0059] Figure 1 The variant of the invention shown optionally further comprises a device 19 in which the reactor inlet stream 2 can be preheated, evaporated and superheated by means of the heat content of the flow of the heat transfer medium 4, wherein these options do not necessarily have to be realized in their entirety but can be realized in any combination. The device 19 is preferably arranged in the heat transfer medium circuit downstream of the reactor 1.

[0060] Reference Mark List

[0061] 1 Reactor

[0062] 2 Reactor inflow material flow

[0063] 3 Reactor effluent stream

[0064] 4 Heat transfer medium

[0065] 5 Recirculation pump

[0066] 6. First heating device

[0067] 7 Second heating device

[0068] 8 Catheter system

[0069] 9 Electrolysis unit

[0070] 10 Hydrogen

[0071] 11 Ammonia

[0072] 12 Heat transfer device

[0073] 13 Reaction medium

[0074] 14 Shell and tube heat exchanger

[0075] 15 tubes

[0076] 16 Catalyst bed

[0077] 17 Shell Space

[0078] 18 loops

[0079] 19 Apparatus for preheating and / or evaporation and / or superheating

Claims

1. A method for producing vinyl chloride by catalytic thermal cracking of 1,2-dichloroethane, wherein the heat required for the thermal cracking is supplied via a liquid heat transfer medium or a condensed heat transfer medium (4), characterized in that: The heat transfer medium (4) is at least temporarily heated at least partially by the thermal energy generated in the oxidation of hydrogen (10), ammonia (11) or a hydrogen-ammonia mixture.

2. The method according to claim 1, characterized in that At least some or all of the hydrogen (10) to be oxidized is produced in an upstream electrolysis unit (9).

3. The method according to any one of the preceding claims, characterized in that The oxidation of hydrogen (10) and / or ammonia (11) is carried out by combustion of hydrogen (10) and / or ammonia (11).

4. The method according to any one of the preceding claims, characterized in that The 1,2-dichloroethane is preheated and / or evaporated and / or superheated by means of the heat transfer medium (4).

5. The method according to any one of the preceding claims, characterized in that The heat transfer medium (4) is at least temporarily partially heated by the heat energy generated by the oxidation of hydrogen (10) and / or ammonia (11) and partially heated by the heat energy generated by the combustion of a fuel different from hydrogen and ammonia, or the heat transfer medium is completely heated by the heat energy generated in the oxidation of hydrogen (10) and / or ammonia (11).

6. The method according to any one of the preceding claims, characterized in that At least one first heating device (6) operated by oxidation of hydrogen (10) and / or ammonia (11) and additionally at least one second heating device (7) operated by combustion of at least one fuel different from hydrogen and ammonia are used to heat the liquid heat transfer medium (4).

7. The method according to any one of the preceding claims, characterized in that The heat transfer medium (4) circulates in a loop (18), and the loop (18) comprises at least one of the first heating devices (6) and a reactor (1) for the catalytic thermal cracking of 1,2-dichloroethane, wherein heat exchange occurs between the reaction medium (13) in the reactor (1) and the heat transfer medium (4).

8. The method according to claims 6 and 7, characterized in that The circuit (18) comprises the second heating device (7).

9. The method according to the preceding claim, characterized in that At least one first heating device (6) and the at least one second heating device (7) are connected in series in the circuit (18).

10. The method according to any one of claims 7 to 9, characterized in that The heat transfer medium (4) circulates in the loop (18) in countercurrent to the flow of the reaction medium (13) through the reactor (1).

11. The method according to any one of the preceding claims, characterized in that The thermal cracking of 1,2-dichloroethane is carried out in a temperature range of 200°C to 400°C.

12. A device for producing vinyl chloride by catalytic thermal cracking of 1,2-dichloroethane, wherein the heat required for the thermal cracking of 1,2-dichloroethane and preferably the heat required for preheating, evaporation and / or superheating of 1,2-dichloroethane is supplied via a liquid heat transfer medium or a condensing heat transfer medium (4), the device comprising at least one reactor (1) for thermal cracking, at least one first heating device (6) and a conduit system (8) for supplying heated heat transfer medium (4) to the reactor (1), the heat transfer medium (4) being heated by means of the first heating device (6), characterized in that The at least one first heating device (6) is designed for the oxidation of hydrogen (10) and / or ammonia (11).

13. Device according to the preceding claim, characterized in that The at least one first heating device (6) is designed for the combustion of hydrogen (10) and / or ammonia (11).

14. Device according to any one of the two preceding claims, characterized in that The device comprises at least one electrolysis unit (9) upstream of the at least one first heating device (6), wherein hydrogen (10) produced in the electrolysis unit (9) is supplied to the at least one first heating device (6).

15. The device according to any one of claims 12 to 14, characterized in that The device additionally comprises at least one second heating device (7) for burning at least one fuel other than hydrogen and ammonia to heat the heat transfer medium (4), the at least one fuel other than hydrogen and ammonia being, for example, methane, natural gas and / or liquid and / or gaseous waste from a chemical plant.

16. The device according to any one of claims 12 to 15, characterized in that The conduit system (8) circulates the heat transfer medium (4) in a circuit (18) comprising the reactor (1) and the at least one first heating device (6).

17. The device according to claims 15 and 16, characterized in that The circuit (18) comprises the at least one second heating device (7).

18. The device according to any one of claims 12 to 17, characterized in that The at least one first heating device (6) and the at least one second heating device (7) are arranged in series in the circuit (18) of the heat transfer medium (4).

19. The device according to any one of claims 12 to 18, characterized in that Means (12) are provided for transferring heat from the heat transfer medium (4) flowing through the reactor (1) to the reaction medium (13).

20. The device according to any one of claims 12 to 19, characterized in that The reactor (1) comprises a shell and tube heat exchanger (14), the tubes (15) of which contain a flow-through catalyst bed (16), the heat transfer medium (4) preferably flowing through the shell space (17) of the reactor (1).

21. The device according to any one of claims 12 to 20, characterized in that At least one device (19) for preheating and / or evaporating and / or superheating 1,2-dichloroethane is integrated into the conduit system (8) of the heat transfer medium (4).

Images