A production system and process for unsaturated hydrocarbons

Abstract

The present invention provides a production system and process for unsaturated hydrocarbons, the system comprising: a combustion heat storage area, a cracking reaction area, a primary distillation area, a carbon dioxide recovery area, a deacidification area, a C2 / C3 fractionation area, a C2 hydrogenation area, a deep cooling area, and a cold separation area; wherein the cracking reaction area comprises a conical reactor body and a quenching heat exchanger connected to the lower end of the conical reactor body. The present invention shortens the reaction residence time, increases the temperature and pressure of the cracking reaction, and reduces the compression energy consumption and heat exchange energy consumption required for subsequent separation by making the cracking raw material directly contact with the high-temperature flue gas and using a conical reactor.

Description

Technical Field

[0001] The invention relates to the field of petrochemical industry, and in particular to a production system and process of unsaturated hydrocarbons. Background Art

[0002] There are currently a variety of production processes for the preparation of unsaturated hydrocarbons, most of which rely on steam tube cracking technology, which has been widely used around the world due to its good cracking gas quality, long continuous production time and mature process equipment technology. However, steam tube cracking technology still has the following shortcomings in its fundamental structure and principle:

[0003] (1) The steam tube cracking method uses the heat released by the combustion of the fuel to indirectly exchange heat with the raw materials inside the metal tube wall to trigger the cracking reaction. It is difficult to significantly improve the reaction temperature, reaction time, and even the thermal efficiency of the reaction. (2) When the fuel and air are mixed and burned, a large amount of carbon dioxide, CO, and NO are generated. x The residual heat in the flue gas is not completely recycled, and the current technology still chooses to directly discharge the flue gas into the atmosphere; (3) Due to the constraints of being unable to increase the cracking temperature and unable to shorten the cracking residence time, the current reaction pressure of the cracking reaction is very low. The subsequent separation of unsaturated hydrocarbons requires the use of a compressor to compress the cracking gas to about 3.6Mpa to achieve the separation of light components. The compression process is very energy-consuming in the actual production process. How to reduce or even avoid compression energy consumption has also become a key research direction. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a production system and process for unsaturated hydrocarbons, which shortens the reaction residence time, increases the temperature and pressure of the cracking reaction, and reduces the compression energy consumption and heat exchange energy consumption required for subsequent separation by making the cracking raw materials directly contact with the high-temperature flue gas and adopting a conical reactor.

[0005] To achieve the above object, the present invention provides a production system of unsaturated hydrocarbons, which comprises: a combustion heat storage area, a cracking reaction area, a primary distillation area, a carbon dioxide recovery area, a deacidification area, a C2 / C3 fractionation area, a C2 hydrogenation area, a deep cooling area, and a cold separation area;

[0006] Wherein, the cracking reaction zone includes a conical reactor body and a quench heat exchanger connected to the lower end of the conical reactor body;

[0007] The outlet of the combustion heat storage zone is connected to the flue gas inlet of the cracking reaction zone, the outlet of the cracking reaction zone is connected to the inlet of the primary distillation zone, the primary distillation zone is provided with a first fraction outlet and a first heavy component outlet, the first fraction outlet is connected to the inlet of the carbon dioxide recovery zone, the outlet of the carbon dioxide recovery zone is connected to the inlet of the deacidification zone, the outlet of the deacidification zone is connected to the inlet of the C2 / C3 fractionation zone, and the C2 / C3 fractionation zone is provided with a second fraction outlet and a third fraction outlet;

[0008] The second fraction outlet is connected to the inlet of the C2 hydrogenation zone, the C2 hydrogenation zone outlet is connected to the inlet of the deep cold zone, the deep cold zone is provided with a main outlet and a first by-product outlet, the main outlet of the deep cold zone is connected to the inlet of the cold separation zone, and the cold separation zone is provided with a first product outlet and a second by-product outlet.

[0009] The existing steam tube cracking method is: furnace tubes and burners are respectively arranged in the cracking furnace, and the heat released by the combustion of fuel is transferred to the cracking raw materials in the furnace tubes through the furnace tubes, causing a cracking reaction, and the smoke generated by the combustion of fuel is directly discharged into the atmosphere.

[0010] Different from the prior art, the unsaturated hydrocarbon production system of the present invention directly mixes high-temperature flue gas with cracking raw materials for heat exchange, greatly improving the heat exchange efficiency and increasing the reaction pressure, reducing the compression energy consumption required for the subsequent separation of cracking gas; when directly mixed, the high-temperature flue gas can reduce the hydrocarbon partial pressure in the cracking reaction system, which can reduce steam consumption compared to the prior art. At the same time, the conical design of the reactor body also ensures an extremely short reaction residence time (millisecond level), short reaction time, high reaction pressure, which can break through the large-scale restrictions and increase the scale of the cracking reaction device. Since the raw materials and high-temperature flue gas are directly mixed for heat exchange, the remaining flue gas containing a large amount of carbon dioxide flows with the cracking gas, and the cracking gas contains a large amount of carbon dioxide, which is convenient for setting up a carbon dioxide recovery work area to capture and recover carbon dioxide in the cracking gas, which greatly reduces carbon emissions compared to the prior art.

[0011] The cracked gas after the carbon dioxide recovery zone still contains a small amount of carbon dioxide, H2S and other acidic gases. In this regard, the present invention also provides a deacidification zone to remove the acidic gases in the cracked products.

[0012] The unsaturated hydrocarbon products produced by the present invention are mainly olefin products, including ethylene and propylene.

[0013] In the above-mentioned unsaturated hydrocarbon production system, preferably, at least one cracking raw material inlet is provided at the top of the conical reactor body, and at least one flue gas inlet is provided at the side wall of the conical reactor body. In the conical cracking reactor of the present invention, the cracking raw material enters the conical cracking reactor through a nozzle, undergoes multi-stage mixing heat exchange with the high-temperature gas from the high-temperature and high-pressure combustion chamber, and a cracking reaction occurs rapidly. Among them, the size of the conical reactor body from the feed end to the quencher (i.e., along the material flow direction) becomes narrower, and the conical design of the reactor body can speed up the flow rate of the cracking gas, thereby reducing the reaction residence time and reducing the occurrence of coking.

[0014] In the above-mentioned unsaturated hydrocarbon production system, preferably, the conical reactor body and the quench heat exchanger are connected via a reducing structure; the reducing structure is preferably a Venturi connection section. The provision of the reducing structure can ensure a higher cracking gas flow rate in the conical cracking reactor, shorten the reaction residence time, and relatively evenly distribute the cracking gas, thereby enhancing the heat exchange effect of the quench heat exchanger.

[0015] In the above-mentioned unsaturated hydrocarbon production system, preferably, the side wall of the conical reactor body is provided with at least two spaced-apart high-temperature flue gas inlets; and the bottom of the quench heat exchanger is provided with a cracking product outlet.

[0016] In the above unsaturated hydrocarbon production system, preferably, the C2 / C3 fractionation zone is a single tower structure or a double tower structure. The cracked gas is clearly separated into C2 and lighter components and C3 and heavier components in the C2 / C3 separation zone.

[0017] In the above-mentioned unsaturated hydrocarbon production system, preferably, the production system further comprises: a depropanization zone, a C3 hydrogenation zone, and a thermal separation zone;

[0018] The third fraction outlet is connected to the inlet of the depropanization zone, the depropanization zone is provided with a fourth fraction outlet and a fifth fraction outlet, the fourth fraction outlet is connected to the inlet of the C3 hydrogenation zone, the outlet of the C3 hydrogenation zone is connected to the inlet of the thermal separation zone, and the thermal separation zone is provided with a second product outlet and a third by-product outlet.

[0019] In the above-mentioned unsaturated hydrocarbon production system, preferably, the C3 hydrogenation zone includes a single or multiple fixed bed reactors.

[0020] In the above-mentioned unsaturated hydrocarbon production system, preferably, the production system further comprises a debutanization zone, the fifth fraction outlet is connected to the inlet of the debutanization zone, and the debutanization zone is provided with a third product outlet and a second heavy component outlet.

[0021] In the above-mentioned unsaturated hydrocarbon production system, preferably, the production system further comprises a first compression zone, the inlet of the first compression zone replaces the inlet of the carbon dioxide recovery zone and is connected to the first fraction outlet, and the outlet of the first compression zone replaces the first fraction outlet and is connected to the inlet of the carbon dioxide recovery zone. In the above-mentioned unsaturated hydrocarbon production system, preferably, the production system further comprises a drying zone, the outlet of the deacidification zone is connected to the inlet of the drying zone, and the outlet of the drying zone is connected to the inlet of the C2 / C3 fractionation zone.

[0022] In the above unsaturated hydrocarbon production system, preferably, the depropanization zone can be a single tower or double tower structure.

[0023] In the above-mentioned unsaturated hydrocarbon production system, preferably, the production system further comprises a second compression zone, the first byproduct outlet of the cryogenic zone is connected to the inlet of the second compression zone, and the outlet of the second compression zone is connected to the inlet of the combustion heat storage zone. More preferably, the second compression zone is a single compressor or multiple compressors.

[0024] In the above-mentioned unsaturated hydrocarbon production system, preferably, the production system further comprises a pressurization zone, the second by-product outlet of the cold separation zone and the third by-product outlet of the hot separation are connected to the inlet of the pressurization zone, and the outlet of the pressurization zone is connected to the auxiliary raw material inlet of the cracking reaction zone. More preferably, the pressurization zone is a single pump or multiple pumps.

[0025] In the above-mentioned unsaturated hydrocarbon production system, preferably, the cracking reactor is provided with a cracking raw material inlet; the flue gas inlet of the cracking reaction zone is arranged in the cracking reactor, and the outlet of the cracking reaction zone is arranged in the rapid cooling chamber.

[0026] The present invention also provides a production process for unsaturated hydrocarbons, which comprises the following steps:

[0027] S1: directly contact the raw material with the high-temperature flue gas to perform a cracking reaction, and then rapidly cool the product to obtain cracking gas;

[0028] S2: performing a primary fractionation on the cracked gas to separate the heavy oil and obtain a light component; performing a secondary fractionation on the light component after removing carbon dioxide and acid to separate C2 and lighter components and C3 and heavier components;

[0029] S3: sequentially subjecting the C2 and lighter components to hydrogenation treatment, cryogenic treatment and cold separation to obtain ethylene products.

[0030] In the cracking reaction of the unsaturated hydrocarbon production process of the present invention, the hydrocarbon raw material absorbs the heat of the high-temperature flue gas and undergoes a cracking reaction to generate hydrogen, methane, ethylene, propylene, butylene, butadiene, C5 and heavy components. The flue gas temperature drops to 300-1000°C and then continues to drop after heat exchange. In addition, the primary distillation is used to preliminarily separate the heavier components in the cracked gas and further recycle the heat in the cracked gas.

[0031] The unsaturated hydrocarbon production process of the present invention enables the raw materials and high-temperature flue gas to directly contact each other in the reactor and quickly exchange heat, thereby greatly improving the heat exchange efficiency.

[0032] In the above-mentioned unsaturated hydrocarbon production process, preferably, the unsaturated hydrocarbon production process is implemented using the above-mentioned unsaturated hydrocarbon production system. S1 of the unsaturated hydrocarbon production process is completed in the cracking reaction area of ​​the above-mentioned saturated hydrocarbon production system, wherein the direct contact between the raw material and the high-temperature flue gas occurs in the conical reactor body, and the product rapid cooling occurs in the rapid cooling heat exchanger.

[0033] In addition, light components flow out from the first fraction outlet, heavy oil flows out from the first heavy component outlet, C2 and lighter components flow out from the second fraction outlet of the C2 / C3 fractionation zone, C3 and heavier components flow out from the third fraction outlet of the C2 / C3 fractionation zone, and ethylene products flow out from the first product outlet.

[0034] In the above-mentioned production process of unsaturated hydrocarbons, preferably, the production process further comprises the following steps:

[0035] S4: Depropanizing the C3 and heavier components (using a depropanizer) to separate the C3 component and the C4 and heavier components;

[0036] S5: The C3 component is subjected to hydrogenation treatment and thermal separation in sequence to obtain a propylene product.

[0037] In the above-mentioned production process of unsaturated hydrocarbons, the C3 component flows out from the fourth fraction outlet of the depropanization zone, the C4 and heavier components flow out from the fifth fraction outlet of the depropanization zone, and the propylene product flows out from the second product outlet.

[0038] In the above-mentioned production process of unsaturated hydrocarbons, preferably, the production process further comprises S6: subjecting the C4 and heavier components to debutanization treatment (using a debutanizer) to separate the C4 component and the C5 and heavier components.

[0039] In the above-mentioned production process of unsaturated hydrocarbons, the C4 component flows out from the third product outlet of the debutanizer section, and the C5 and heavier components flow out from the second heavy component outlet of the debutanizer section.

[0040] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S1, the temperature of the cracking reaction is 800-1500° C., and the reaction pressure is 1-6 MPa.

[0041] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S1, the product is rapidly cooled to 200-400°C.

[0042] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S1, the high-temperature flue gas is obtained by mixed combustion of fuel and combustion aid, and the pressure of the high-temperature flue gas is 1-6MPa and the temperature is 1200-3000°C.

[0043] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S1, the fuel is selected from natural gas, gasoline or diesel; the combustion aid is selected from oxygen, air or a mixture of the two; and the raw materials are preheated.

[0044] In the above-mentioned production process of unsaturated hydrocarbons, preferably, S2 also includes pressurizing the light component to 1.5-5Mpag, preferably 2-4Mpag, before decarbonation. Since the cracking reaction zone directly exchanges heat between the cracking raw material and the high-temperature flue gas to produce a higher reaction pressure, the cracking gas and the light components after distillation thereof also have a higher pressure. When the pressure of the light component has reached or exceeded the standard value of the air pressure for carbon dioxide recovery and treatment, no compression is required, which can greatly save compression energy consumption. When the pressure of the light component does not reach the corresponding standard value of the air pressure, even if additional compression of the light component is required, the number and power of the compressors will be reduced relative to the prior art, thereby reducing compression energy consumption.

[0045] When the pressure in the cracking reactor is not high enough, the unsaturated hydrocarbon production process of the present invention pressurizes the light component cracking gas to make its pressure reach a corresponding level, so as to improve the subsequent fractionation effect.

[0046] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S2, the method for removing carbon dioxide is to capture carbon dioxide in the light component by physical adsorption or chemical adsorption; when chemical adsorption is adopted, the capture solvent is selected from an alcoholamine solution, preferably a methyldiethanolamine solution.

[0047] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S2, the deacidification treatment method is to remove the acidic gas in the light component by solvent absorption; the absorption solvent used is preferably sodium hydroxide solvent.

[0048] In the above-mentioned production process of unsaturated hydrocarbons, preferably, the acid gas includes carbon dioxide and H2S; and the content of acid gas in the light component after deacidification is less than 1 ppm.

[0049] In the above-mentioned production process of unsaturated hydrocarbons, preferably, S2 also includes drying the deacidified light components. The deacidified cracking products contain a large amount of water, which will be removed in the drying area, and the drying area is divided into gas phase drying and liquid phase drying.

[0050] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S3, the hydrogenation treatment of C2 and lighter components is used to remove alkynes (including acetylene) therein, and the hydrogenation treatment uses a catalyst and a fixed bed reactor.

[0051] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S3, the cryogenic treatment of C2 and lighter components is used to separate methane and hydrogen therefrom, and the separated methane and hydrogen are compressed and used as auxiliary fuels to generate the high-temperature flue gas. The cryogenic treatment can crack the C2 and lighter components into lighter components such as methane and hydrogen. The methane and hydrogen flow out from the first by-product outlet.

[0052] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S3, the cold separation of C2 and lighter components is used to separate saturated alkanes containing ethane and obtain the ethylene product, and the saturated alkanes containing ethane are pressurized and sent to the cracking reactor as a by-raw material. The ethylene product obtained by the present invention can be sent to the outside of the limit or to a downstream device. The ethylene product flows out from the first product outlet, and the ethane flows out from the second by-product outlet.

[0053] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S5, the hydrogenation treatment of the C3 component is used to remove alkynes and diolefins therein. The hydrogenation treatment selectively removes impurities such as alkynes in the C3 component by hydrogenation under the action of a catalyst.

[0054] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S5, the thermal separation of the C3 component is used to separate the saturated alkanes containing propane therein and obtain the propylene product, and the saturated alkanes containing propane are pressurized and fed into the cracking reactor as a by-raw material. The saturated alkanes flow out from the third by-product outlet of the thermal separation zone, and the propylene product flows out from the second product outlet of the thermal separation zone.

[0055] In the above-mentioned production process of unsaturated hydrocarbons, preferably, in S6, the separated C4 component is sent out of the boundary area as a product, and the separated C5 and heavier components (pyrolysis gasoline) are also sent out of the boundary area or to downstream devices as products. The C4 component flows out from the third product outlet of the debutanizer section, and the C5 and heavier components flow out from the second heavy component outlet of the debutanizer section.

[0056] The technical solution provided by the present invention has the following beneficial effects:

[0057] (1) The present invention directly mixes the high-temperature flue gas generated in the combustion chamber with the raw material for heat exchange and generates a cracking reaction, which can increase the cracking reaction temperature and reaction pressure, thereby increasing the cracking reaction depth, reducing the compression energy consumption in the subsequent separation process of the cracking gas, and at the same time making the most of the heat energy of fuel combustion (theoretical energy utilization efficiency is 100%);

[0058] (2) The present invention directly mixes the high-temperature gas with the cracking raw material for cracking, so that carbon dioxide enters the cracking gas and is convenient for centralized capture and recovery, thereby reducing carbon emissions; in addition, carbon dioxide, carbon monoxide, water, etc. in the high-temperature gas can serve as inert gases to reduce the hydrocarbon partial pressure of the cracking reaction system, and compared with the traditional tubular cracking furnace, a large amount of dilution steam can be saved;

[0059] (3) The operating pressure of the cracking reactor in the present invention breaks the limitation of the traditional tubular cracking furnace, and the cracking reaction can be carried out within 1-6 MPa. The cone-shaped cracking reactor greatly shortens the reaction residence time and prevents the problem of coking under high pressure conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a schematic diagram of the process of the unsaturated hydrocarbon production system of Example 1;

[0061] Figure 2 This is a schematic diagram of the structure of the cracking reaction zone in Example 1.

[0062] Description of Figure Numbers:

[0063] 01. Combustion and thermal storage area; 02. Cracking reaction area; 03. Primary distillation area; 04. First compression area; 05. Carbon dioxide recovery area; 06. Deacidification area; 07. Drying area; 08. C2 / C3 fractionation area; 09. C2 hydrogenation area; 10. Cryogenic area; 11. Cold separation area; 12. Depropanization area; 13. C3 hydrogenation area; 14. Hot separation area; 15. Debutanization area; 16. Second compression area; 17. Pressurization area;

[0064] 021. Conical reactor body; 022. Rapid cooling heat exchanger; 023. Venturi connecting section; 024. Cracking raw material inlet; 025. Flue gas inlet. DETAILED DESCRIPTION

[0065] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0066] Example 1

[0067] This embodiment provides a production system of unsaturated hydrocarbons, such as Figure 1As shown, the production system includes: combustion heat storage area 01, cracking reaction area 02, primary distillation area 03, first compression area 04, carbon dioxide recovery area 05, deacidification area 06, drying area 07, C2 / C3 fractionation area 08, C2 hydrogenation area 09, deep cooling area 10, cold separation area 11, depropanization area 12, C3 hydrogenation area 13, hot separation area 14, debutanization area 15, second compression area 16, pressurization area 17;

[0068] Among them, Figure 2 Therefore, the cracking reaction zone 02 includes a conical reactor body 021, and a quench heat exchanger 022 connected to the lower end of the conical reactor body 021 through a venturi connecting section 023, a cracking raw material inlet 024 is provided at the top of the conical reactor body, and at least two flue gas inlets 025 are provided at intervals on the side wall; a cracking product outlet is provided at the bottom of the quench heat exchanger.

[0069] The outlet of the combustion heat storage area 01 is connected to the flue gas inlet 025 of the cracking reaction area 02, the cracking product outlet of the cracking reaction area 02 is connected to the inlet of the primary distillation area 03, the primary distillation area 03 is provided with a first fraction outlet and a first heavy component outlet, the first fraction outlet is connected to the inlet of the first compression area 04, the outlet of the first compression area 04 is connected to the inlet of the carbon dioxide recovery area 05, the outlet of the carbon dioxide recovery area 05 is connected to the inlet of the deacidification area 06, the outlet of the deacidification area 06 is connected to the inlet of the drying area 07, the outlet of the drying area 07 is connected to the inlet of the C2 / C3 fractionation area 08, and the C2 / C3 fractionation area 08 is provided with a second fraction outlet and a third fraction outlet;

[0070] The outlet of the second fraction is connected to the inlet of the C2 hydrogenation zone 09, and the outlet of the C2 hydrogenation zone 09 is connected to the inlet of the deep cold zone 10, and the deep cold zone 10 is provided with a main outlet and a first by-product outlet; the main outlet of the deep cold zone 10 is connected to the inlet of the cold separation zone 11, and the cold separation zone 11 is provided with a first product outlet and a second by-product outlet; the second by-product outlet of the cold separation zone 11 is connected to the inlet of the pressurization zone 17, and the outlet of the pressurization zone 17 is connected to the auxiliary raw material inlet of the cracking reaction zone 02; the first by-product outlet of the deep cold zone 10 is connected to the inlet of the second compression zone 16, and the outlet of the second compression zone 16 is connected to the inlet of the combustion heat storage zone 01;

[0071] The third fraction outlet is connected to the inlet of the depropanizer section 12, and the depropanizer section 12 is provided with a fourth fraction outlet and a fifth fraction outlet, and the fourth fraction outlet is connected to the inlet of the C3 hydrogenation section 13, and the outlet of the C3 hydrogenation section 13 is connected to the inlet of the thermal separation section 14, and the thermal separation section 14 is provided with a second product outlet and a third by-product outlet, and the third by-product outlet of the thermal separation is connected to the inlet of the pressurizing section 17; the fifth fraction outlet is connected to the inlet of the debutanizer section 15, and the debutanizer section 15 is provided with a third product outlet and a second heavy component outlet.

[0072] Example 2

[0073] This embodiment provides a production process for unsaturated hydrocarbons, which is implemented using the production system for unsaturated hydrocarbons in Embodiment 1 and includes the following steps:

[0074] S1: The fuel is burned under pure oxygen to obtain high-temperature flue gas with a pressure of 6 MPa and a temperature of 1200°C, and then the cracking raw material and the high-temperature flue gas are directly contacted in the conical reactor body 021 of the cracking reaction zone 02 to carry out cracking reaction. The temperature of the cracking reaction is 1000°C and the reaction pressure is 6 MPa. The product is rapidly cooled to 400°C in the rapid cooling heat exchanger 022 to obtain cracking gas;

[0075] S2: performing a primary fractionation on the cracked gas to separate the heavy oil and obtain a light component, removing carbon dioxide, deacidifying and drying the light component, and then performing a secondary fractionation to separate C2 and lighter components and C3 and heavier components;

[0076] S3: Hydrogenate the C2 and lighter components to remove acetylenes, perform cryogenic treatment to separate lighter components such as methane and hydrogen, and then perform cold separation to separate saturated alkanes containing ethane to obtain ethylene products; methane, hydrogen and other lighter components are compressed and sent to the combustion chamber as auxiliary fuels to generate the high-temperature flue gas, and the saturated alkanes containing ethane are pressurized and sent to the cracking reactor as auxiliary raw materials;

[0077] S4: performing a depropanization treatment on the C3 and heavier components to separate the C3 component and the C4 and heavier components;

[0078] S5: hydrogenating the C3 component to remove alkynes and dienes therein, and then performing thermal separation to separate saturated alkanes containing propane to obtain a propylene product; the saturated alkanes containing propane are pressurized and fed into the cracking reactor as a by-raw material;

[0079] S6: performing debutanization on the C4 and heavier components to separate the C4 component and the C5 and heavier components.

[0080] In this embodiment, the cracking reaction pressure is higher than 4 MPa, so the compression process of the light components in the initial fractionation can be omitted and the carbon dioxide can be directly removed.

[0081] Compared with the traditional process, the unsaturated hydrocarbon production process of this embodiment can reduce the dilution steam consumption by more than 90%, reduce the total compression energy consumption by 50-60%, and reduce carbon emissions by more than 90%.

[0082] Example 3

[0083] This embodiment provides a production process for unsaturated hydrocarbons, which is implemented using the production system for unsaturated hydrocarbons in Embodiment 1 and includes the following steps:

[0084] S1: The fuel is burned under pure oxygen to obtain high-temperature flue gas with a pressure of 1 MPa and a temperature of 1200°C, and then the cracking raw material and the high-temperature flue gas are directly contacted in the conical reactor body 021 of the cracking reaction zone 02 to carry out cracking reaction. The temperature of the cracking reaction is 1000°C and the reaction pressure is 1 MPa. The product is rapidly cooled to 400°C in the rapid cooling heat exchanger 022 to obtain cracking gas;

[0085] S2: performing a primary fractionation on the cracked gas to separate the heavy oil and obtain a light component, compressing the light component to 3.8 MPa, and then removing carbon dioxide, deacidifying, and drying it, and then performing a secondary fractionation to separate C2 and lighter components and C3 and heavier components;

[0086] S3-S6 are the same as in Example 2.

[0087] The cracking reaction pressure of this embodiment does not exceed 4Mpa, and the light components after the initial fractionation need to be compressed before removing carbon dioxide. Despite the additional compression, the production process of unsaturated hydrocarbons in this embodiment also greatly saves compression energy consumption compared with the traditional process. The production process of unsaturated hydrocarbons in this embodiment can reduce the consumption of dilution steam by more than 90%, reduce the total compression energy consumption by 20-30%, and reduce carbon emissions by more than 90%.

Claims

1. A production system for unsaturated hydrocarbons, comprising: Combustion heat storage area, cracking reaction area, primary distillation area, carbon dioxide recovery area, deacidification area, C2 / C3 fractionation area, C2 hydrogenation area, deep cold area, cold separation area; The cracking reaction zone includes a conical cracking reactor body and a quench heat exchanger connected to the lower end of the conical cracking reactor body; at least one cracking raw material inlet is provided on the top of the conical cracking reactor body, and at least one flue gas inlet is provided on the side wall of the conical cracking reactor body; the size of the conical cracking reactor body narrows from the feed end to the quench heat exchanger; The outlet of the combustion heat storage zone is connected to the flue gas inlet of the cracking reaction zone, the outlet of the cracking reaction zone is connected to the inlet of the primary distillation zone, the primary distillation zone is provided with a first fraction outlet and a first heavy component outlet, the first fraction outlet is connected to the inlet of the carbon dioxide recovery zone, the outlet of the carbon dioxide recovery zone is connected to the inlet of the deacidification zone, the outlet of the deacidification zone is connected to the inlet of the C2 / C3 fractionation zone, and the C2 / C3 fractionation zone is provided with a second fraction outlet and a third fraction outlet; The second fraction outlet is connected to the inlet of the C2 hydrogenation zone, the C2 hydrogenation zone outlet is connected to the inlet of the deep cold zone, the deep cold zone is provided with a main outlet and a first by-product outlet, the main outlet of the deep cold zone is connected to the inlet of the cold separation zone, and the cold separation zone is provided with a first product outlet and a second by-product outlet.

2. The unsaturated hydrocarbon production system according to claim 1, wherein: It also includes: depropanization area, C3 hydrogenation area, thermal separation area; The third fraction outlet is connected to the inlet of the depropanization zone, the depropanization zone is provided with a fourth fraction outlet and a fifth fraction outlet, the fourth fraction outlet is connected to the inlet of the C3 hydrogenation zone, the outlet of the C3 hydrogenation zone is connected to the inlet of the thermal separation zone, and the thermal separation zone is provided with a second product outlet and a third by-product outlet.

3. The unsaturated hydrocarbon production system according to claim 2, wherein: It also includes a debutanization section, the fifth fraction outlet is connected to the inlet of the debutanization section, and the debutanization section is provided with a third product outlet and a second heavy component outlet.

4. The unsaturated hydrocarbon production system according to claim 1, wherein: It also includes a first compression zone, the first fraction outlet is connected to the inlet of the first compression zone instead of the inlet of the carbon dioxide recovery zone, and the outlet of the first compression zone is connected to the inlet of the carbon dioxide recovery zone instead of the first fraction outlet.

5. The unsaturated hydrocarbon production system according to claim 1, wherein: It also includes a drying section, the outlet of the deacidification section is connected to the inlet of the drying section, and the outlet of the drying section is connected to the inlet of the C2 / C3 fractionation section.

6. The unsaturated hydrocarbon production system according to claim 1, wherein: It also includes a second compression zone, the first byproduct outlet of the cryogenic zone is connected to the inlet of the second compression zone, and the outlet of the second compression zone is connected to the inlet of the combustion heat storage zone.

7. The unsaturated hydrocarbon production system according to claim 2, wherein: It also includes a pressurizing zone, the second by-product outlet of the cold separation zone and the third by-product outlet of the hot separation zone are connected to the inlet of the pressurizing zone, and the outlet of the pressurizing zone is connected to the auxiliary raw material inlet of the cracking reaction zone.

8. The unsaturated hydrocarbon production system according to claim 1, wherein: The conical cracking reactor body is provided with a cracking raw material inlet; the flue gas inlet of the cracking reaction zone is arranged in the cracking reactor, and the outlet of the cracking reaction zone is arranged in the quench heat exchanger.

9. A process for producing unsaturated hydrocarbons, which is implemented using the unsaturated hydrocarbon production system according to any one of claims 1 to 8, and the unsaturated hydrocarbon production process comprises the following steps: S1: directly contact the raw material with the high-temperature flue gas in a reactor to perform a cracking reaction, and rapidly cool the product to obtain cracking gas; S2: performing a primary fractionation on the cracked gas to separate the heavy oil and obtain a light component; performing a secondary fractionation on the light component after removing carbon dioxide and acid to separate C2 and lighter components and C3 and heavier components; S3: sequentially subjecting the C2 and lighter components to hydrogenation treatment, cryogenic treatment and cold separation to obtain ethylene products.

10. The process for producing unsaturated hydrocarbons according to claim 9, wherein: It also includes the following steps: S4: performing a depropanization treatment on the C3 and heavier components to separate the C3 component and the C4 and heavier components; S5: The C3 component is subjected to hydrogenation treatment and thermal separation in sequence to obtain a propylene product.

11. The process for producing unsaturated hydrocarbons according to claim 10, wherein: The method further comprises S6: performing debutanization treatment on the C4 and heavier components to separate the C4 component and the C5 and heavier components.

12. The process for producing unsaturated hydrocarbons according to claim 9, wherein: In S1, the temperature of the cracking reaction is 800-1500°C, and the reaction pressure is 1-6MPa.

13. The process for producing unsaturated hydrocarbons according to claim 9, wherein: In S1, the product is rapidly cooled to 200-400°C.

14. The process for producing unsaturated hydrocarbons according to claim 9, wherein: In S1, the high-temperature flue gas is obtained by burning a mixture of fuel and an oxidant, and the pressure of the high-temperature flue gas is 1-6 MPa and the temperature is 1200-3000°C.

15. The process for producing unsaturated hydrocarbons according to claim 14, wherein: In S1, the fuel is selected from natural gas, gasoline or diesel; the combustion aid is selected from oxygen, air or a mixture of the two.

16. The process for producing unsaturated hydrocarbons according to claim 9, wherein: S2 also includes pressurizing the light component to 1.5-5 MPag before removing carbon dioxide.

17. The process for producing unsaturated hydrocarbons according to claim 16, wherein: The light components were pressurized to 2-4 MPag.

18. The process for producing unsaturated hydrocarbons according to claim 9, wherein: In S2, the treatment method for removing carbon dioxide is to capture carbon dioxide in the light component by physical adsorption or chemical adsorption; when chemical adsorption is adopted, the capture solvent used is selected from alcohol amine solution.

19. The process for producing unsaturated hydrocarbons according to claim 18, wherein: In S2, the capture solvent is a methyldiethanolamine solution.

20. The process for producing unsaturated hydrocarbons according to claim 9, wherein: In S2, the deacidification treatment method is to remove the acidic gas in the light component by solvent absorption; the absorption solvent used is selected from sodium hydroxide solvent.

21. The process for producing unsaturated hydrocarbons according to claim 9, wherein: S2 also includes drying the deacidified light components.

22. The process for producing unsaturated hydrocarbons according to claim 9, wherein: In S3, the hydrogenation treatment of C2 and lighter components is used to remove acetylenes therein, and the hydrogenation treatment uses a catalyst and a fixed bed reactor.

23. The process for producing unsaturated hydrocarbons according to claim 9, wherein: In S3, the cryogenic treatment of C2 and lighter components is used to separate methane and hydrogen therefrom, and the separated methane and hydrogen are compressed and used as auxiliary fuels to generate the high-temperature flue gas.

24. The process for producing unsaturated hydrocarbons according to claim 9, wherein: In S3, the cold separation of C2 and lighter components is used to separate saturated alkanes containing ethane and obtain the ethylene product. The saturated alkanes containing ethane are pressurized and fed into the conical cracking reactor body as a by-raw material.

25. The process for producing unsaturated hydrocarbons according to claim 10, wherein: In S5, the hydrogenation treatment of the C3 component is used to remove acetylenes and dienes therein, and the hydrogenation treatment uses a catalyst and a fixed bed reactor.

26. The process for producing unsaturated hydrocarbons according to claim 10, wherein: In S5, the thermal separation of the C3 component is used to separate the saturated alkanes containing propane and obtain the propylene product. The saturated alkanes containing propane are pressurized and fed into the conical cracking reactor body as a by-raw material.

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