Cyclohexane dehydrogenation device

Abstract

The utility model discloses a cyclohexane dehydrogenation device, which is characterized in that raw materials cyclohexane and hydrogen are jointly sent to a raw material preheater for preheating, then are heated in a raw material heater and then enter a dehydrogenation reactor, a dehydrogenation product is cooled by an outlet cooler, and the cooled product is subjected to gas-liquid separation by a first gas-liquid separation tank; the gas enters the hydrogen compressor to be pressurized, then is cooled and then enters the second gas-liquid separation tank to be separated again, one part of the gas separated by the second gas-liquid separation tank returns to the hydrogen raw material inlet, and the other part of the gas enters the hydrogen impurity removal and purification device to be purified and then is subjected to hydrogen energy recycling; liquid separated by the second gas-liquid separation tank returns to the first gas-liquid separation tank, and a liquid phase outlet is connected with a benzene storage tank through a pump and a pipeline. The by-product cyclohexane in the cyclohexanol production process is completely converted into benzene, the benzene is combined with an existing device and directly enters an existing system, and the advantage that benzene refining separation is not needed is embodied.

Description

Technical Field

[0001] The utility model belongs to the field of recycling by-products of cyclohexanol production devices, and specifically relates to a cyclohexane dehydrogenation device. Background Art

[0002] Cyclohexanol is an excellent medium-to-high boiling point organic chemical product, mainly used as an intermediate raw material for the production of important chemical products such as adipic acid, caprolactam and polyamide-66. Cyclohexane is a by-product of cyclohexanol produced by direct hydration. With the continuous increase in the production capacity of the main product cyclohexanol, the output of by-product cyclohexane has also increased significantly. The presence of this product not only reduces the carbon atom utilization rate of benzene, but also increases the energy consumption of cyclohexanol production. In addition, cyclohexane is volatile and extremely flammable, forming an explosive mixture with air, which poses great risks during transportation and storage.

[0003] The effective utilization of byproduct cyclohexane has always been a production problem that has troubled enterprises. Almost all enterprises have adopted the method of selling it at a low price, which also brings risks in material storage and transportation, and increases the operating costs of enterprises. Therefore, it has become an urgent problem to "squeeze out" the byproducts produced in the process of producing cyclohexanol and avoid the safety risks brought by the export of cyclohexane.

[0004] Through the new cyclohexane dehydrogenation process technology, the by-product cyclohexane produced by the hydration cyclohexanol unit is converted into benzene and hydrogen, realizing the production closed loop of "raw material → by-product → raw material". It not only greatly increases the utilization rate of carbon atoms, but also avoids the risks in the transportation and storage process. This process can achieve technical breakthroughs, solve the technical problems of the industry, ensure the green, efficient and stable operation of the enterprise, and further enhance the company's core competitiveness. Utility Model Content

[0005] The utility model aims to provide a cyclohexane dehydrogenation device.

[0006] Based on the above purpose, the utility model adopts the following technical solutions:

[0007] A cyclohexane dehydrogenation device comprises a raw material preheater, a raw material heater, a dehydrogenation reactor, a filter, an outlet cooler, a first gas-liquid separation tank, a hydrogen compressor, a gas cooler and a second gas-liquid separation tank which are sequentially connected through pipelines. The dehydrogenation reactor is connected to a heat transfer oil heating system. The pipe side inlet of the raw material preheater is connected to a cyclohexane storage tank and a hydrogen pipeline through a pipeline so that hydrogen and cyclohexane are mixed and enter the raw material preheater together. The pipe side outlet of the raw material preheater is connected to the raw material heater. The outlet of the filter is connected to the shell side inlet of the raw material preheater. The shell side outlet of the raw material preheater is connected to the inlet of the outlet cooler. The first gas-liquid separation tank is provided with a raw material inlet, a liquid outlet, a gas outlet and a liquid return port. The outlet of the outlet cooler is connected to the raw material inlet of the first gas-liquid separation tank. The gas outlet of the first gas-liquid separation tank is connected to the hydrogen compressor. The outlet of the hydrogen compressor is sequentially connected to the gas cooler and the second gas-liquid separation tank. The liquid outlet of the second gas-liquid separation tank is connected to the liquid return port of the first gas-liquid separation tank. The liquid outlet of the first gas-liquid separation tank is connected to a benzene storage tank.

[0008] Furthermore, the gas outlet of the second gas-liquid separation tank is provided with two branches, one branch is connected to the hydrogen impurity removal device, and the other branch is connected to the hydrogen pipeline.

[0009] Furthermore, the thermal oil heating system includes a thermal oil expansion tank, a thermal oil separation tank, a thermal oil pump and a thermal oil furnace, the outlet of the thermal oil furnace is connected to the thermal oil inlet of the dehydrogenation reactor through a pipeline, the thermal oil outlet of the dehydrogenation reactor is connected to the inlet of the thermal oil expansion tank through a pipeline, the outlet of the thermal oil expansion tank is connected to the top inlet of the thermal oil separation tank through a pipeline, and the bottom outlet of the thermal oil separation tank is connected to the inlet of the thermal oil furnace via the thermal oil pump.

[0010] Furthermore, a benzene pump is provided on the pipeline between the first gas-liquid separation tank and the benzene storage tank.

[0011] Furthermore, a drain pipe is provided on the top of the thermal oil expansion tank.

[0012] Furthermore, the tube side outlet of the feed preheater is connected to the tube side inlet of the feed heater, the tube side outlet of the feed heater is connected to the feed inlet of the dehydrogenation reactor, and the shell side inlet of the feed heater is connected to a medium-pressure steam pipeline.

[0013] Furthermore, the shell side outlet of the raw material preheater is connected to the shell side inlet of the outlet cooler, the shell side outlet of the outlet cooler is connected to the raw material inlet of the first gas-liquid separation tank, and the tube side inlet of the outlet cooler is connected to the cooling water pipeline.

[0014] Furthermore, the outlet of the air compressor is connected to the shell side inlet of the gas cooler, the shell side outlet of the gas cooler is connected to the inlet of the second gas-liquid separation tank, and the tube side inlet of the gas cooler is connected to the cooling water pipeline.

[0015] The utility model recovers cyclohexane, a byproduct of the cyclohexanol production process, and completely converts the cyclohexane into benzene. The cyclohexane is directly introduced into the existing system in combination with the existing device, thus showing the advantage of not requiring benzene refining and separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model;

[0017] In the figure: 1. raw material preheater, 2. raw material heater, 3. dehydrogenation reactor, 4. filter, 5. outlet cooler, 6. first gas-liquid separation tank, 7. benzene pump, 8. hydrogen compressor, 9. gas cooler, 10. second gas-liquid separation tank, 11. thermal oil expansion tank, 12. thermal oil separation tank, 13. thermal oil furnace, 14. thermal oil pump. DETAILED DESCRIPTION

[0018] The technical solution of the utility model is further described in detail below in conjunction with the accompanying drawings.

[0019] A cyclohexane dehydrogenation device, such as Figure 1 As shown, it includes a raw material preheater 1, a raw material heater 2, a dehydrogenation reactor 3, a filter 4, an outlet cooler 5, a first gas-liquid separator 6, a benzene pump 7, a hydrogen compressor 8, a gas cooler 9, a second gas-liquid separator 10, a heat transfer oil expansion tank 11, a heat transfer oil separator 12, a heat transfer oil furnace 13 and a heat transfer oil pump 14. The tube side inlet of the raw material preheater 1 is connected to the cyclohexane storage tank and the hydrogen pipeline through a pipeline so that hydrogen and cyclohexane are mixed and enter the raw material preheater 1 together, the tube side outlet of the raw material preheater 1 is connected to the tube side inlet of the raw material heater 2, the tube side outlet of the raw material heater 2 is connected to the raw material inlet of the dehydrogenation reactor 3, the shell side inlet of the raw material heater 2 is connected to medium-pressure steam as a heat source, the raw material outlet of the dehydrogenation reactor 3 is connected to the inlet of the outlet filter 4, the outlet of the outlet filter 4 is connected to the shell side inlet of the raw material preheater 1, the shell side outlet of the raw material preheater 1 is connected to the shell side inlet of the dehydrogenation reactor outlet cooler 5, and the first gas-liquid separator 6 is provided with A raw material inlet, a liquid outlet, a gas outlet and a liquid return port, cooling water is introduced into the tube-side inlet of the outlet cooler 5, the shell-side outlet of the outlet cooler 5 is connected to the raw material inlet of the first gas-liquid separation tank 6, the gas outlet of the first gas-liquid separation tank 6 is connected to the hydrogen compressor 8, the outlet of the hydrogen compressor 8 is connected to the shell-side inlet of the gas cooler 9, the shell-side outlet of the gas cooler 9 is connected to the second gas-liquid separation tank 10, cooling water is introduced into the tube-side inlet of the gas cooler 9, the liquid outlet of the second gas-liquid separation tank 10 is connected to the liquid return port of the first gas-liquid separation tank 6, and the liquid outlet of the first gas-liquid separation tank 6 is connected to the benzene storage tank through a pipeline and a benzene pump 7 arranged on the pipeline.

[0020] The gas outlet of the second gas-liquid separation tank 10 is provided with two branches, one branch is connected to the hydrogen impurity removal device, and the other branch is connected to the hydrogen pipeline.

[0021] The outlet of the thermal oil furnace 13 is connected to the thermal oil inlet of the dehydrogenation reactor 3 through a pipeline, the thermal oil outlet of the dehydrogenation reactor 3 is connected to the inlet of the thermal oil expansion tank 11 through a pipeline, the outlet of the thermal oil expansion tank 11 is connected to the top inlet of the thermal oil separation tank 12 through a pipeline, and the bottom outlet of the thermal oil separation tank 12 is connected to the inlet of the thermal oil furnace 13 through a thermal oil pump 14. An emptying pipeline is provided at the top of the thermal oil expansion tank 11.

[0022] The process of cyclohexane dehydrogenation using the above-mentioned cyclohexane dehydrogenation device is as follows:

[0023] The volume ratio of raw material cyclohexane to carrier gas hydrogen is 1:10. The raw material cyclohexane is at room temperature and pressure, and the hydrogen pressure is 0.7 MPaG. They are sent to the raw material preheater 1 together with the hot material with a temperature of 350°C coming out of the dehydrogenation reactor 3 for heat exchange, and the heat of the material coming out of the dehydrogenation reactor 3 is fully recovered and utilized. The medium-pressure steam with a pressure of 1.3±0.1MPaG and a temperature of 200±5°C is used as a heat source to heat the raw material to 120~150°C through the raw material heater 2, and then enters the dehydrogenation reactor 3 for dehydrogenation reaction. The product coming out of the dehydrogenation reactor 3 is first filtered through a filter 4 with a filtration accuracy of 5~10 microns, and then heat-exchanged with the raw material in the raw material preheater 1 for further cooling, and then passed through the outlet cooler 5 using a temperature of 5~8°C The cooling water is used for cooling, and the temperature after cooling is 40~60℃. The gas enters the first gas-liquid separation tank 6 for gas-liquid separation. The liquid is stored in the first gas-liquid separation tank 6. The gas is discharged to the benzene storage tank through the benzene pump 7 according to the liquid level of the first gas-liquid separation tank 6. The gas enters the hydrogen compressor 8 for pressurization to 3.0MPaG and a temperature of 70~80℃. After that, the gas cooler 9 uses cooling water with a temperature of 5~8℃ to cool the gas to 10~25℃. The gas enters the second gas-liquid separation tank 10 for the second gas-liquid separation. The liquid returns to the first gas-liquid separation tank 6. 10~20% of the gas returns to the hydrogen raw material inlet for use as a carrier gas for cyclohexane dehydrogenation, and the remaining 80~90% enters the hydrogen impurity removal device for use as a benzene hydrogenation raw material.

[0024] The dehydrogenation reactor 3 is equipped with a heating system, which uses heat transfer oil as a heat source. After the heat transfer oil is heated to 450°C in the heat transfer furnace 13, it enters the dehydrogenation reactor 3 from the bottom. The heat transfer oil discharged from the top with a temperature of 350°C enters the heat transfer oil expansion tank 11, and the gas phase is filtered to the emission standard and then discharged. The liquid phase heat transfer oil enters the heat transfer oil separation tank 12 and is then pumped into the heat transfer oil furnace 13 by the heat transfer oil pump 14 for continued circulation heating.

[0025] Through the above-mentioned device and process, the conversion rate of cyclohexane reached 99.77% and the benzene selectivity reached 99.91%.

[0026] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions for the specific implementation of the present invention rather than to limit it. Ordinary technicians in the relevant technical field should understand that any equivalent substitution or obvious modification of the implementation mode of the present invention without changing its performance or use, without violating the purpose of the present invention, should be included in the scope of protection requested by the present invention.

Claims

1. A cyclohexane dehydrogenation device, characterized in that: The invention comprises a raw material preheater, a raw material heater, a dehydrogenation reactor, a filter, an outlet cooler, a first gas-liquid separation tank, a hydrogen compressor, a gas cooler and a second gas-liquid separation tank which are sequentially connected through pipelines. The dehydrogenation reactor is connected to a heat transfer oil heating system. The pipe side inlet of the raw material preheater is connected to a cyclohexane storage tank and a hydrogen pipeline through a pipeline so that hydrogen and cyclohexane are mixed and enter the raw material preheater together. The pipe side outlet of the raw material preheater is connected to the raw material heater. The outlet of the filter is connected to the shell side inlet of the raw material preheater. The shell side outlet of the raw material preheater is connected to the inlet of the outlet cooler. The first gas-liquid separation tank is provided with a raw material inlet, a liquid outlet, a gas outlet and a liquid return port. The outlet of the outlet cooler is connected to the raw material inlet of the first gas-liquid separation tank. The gas outlet of the first gas-liquid separation tank is connected to the hydrogen compressor. The outlet of the hydrogen compressor is sequentially connected to the gas cooler and the second gas-liquid separation tank. The liquid outlet of the second gas-liquid separation tank is connected to the liquid return port of the first gas-liquid separation tank. The liquid outlet of the first gas-liquid separation tank is connected to a benzene storage tank.

2. The cyclohexane dehydrogenation device according to claim 1, characterized in that: The gas outlet of the second gas-liquid separation tank is provided with two branches, one branch is connected to the hydrogen impurity removal device, and the other branch is connected to the hydrogen pipeline.

3. The cyclohexane dehydrogenation device according to claim 1, characterized in that: The thermal oil heating system comprises a thermal oil expansion tank, a thermal oil separation tank, a thermal oil pump and a thermal oil furnace, wherein the outlet of the thermal oil furnace is connected to the thermal oil inlet of the dehydrogenation reactor through a pipeline, the thermal oil outlet of the dehydrogenation reactor is connected to the inlet of the thermal oil expansion tank through a pipeline, the outlet of the thermal oil expansion tank is connected to the top inlet of the thermal oil separation tank through a pipeline, and the bottom outlet of the thermal oil separation tank is connected to the inlet of the thermal oil furnace through the thermal oil pump.

4. The cyclohexane dehydrogenation device according to claim 1, characterized in that: A benzene pump is also provided on the pipeline between the first gas-liquid separation tank and the benzene storage tank.

5. The cyclohexane dehydrogenation device according to claim 1, characterized in that: A drain pipe is provided on the top of the thermal oil expansion tank.

6. The cyclohexane dehydrogenation device according to claim 1, characterized in that: The tube side outlet of the feed preheater is connected to the tube side inlet of the feed heater, the tube side outlet of the feed heater is connected to the feed inlet of the dehydrogenation reactor, and the shell side inlet of the feed heater is connected to a medium-pressure steam pipeline.

7. The cyclohexane dehydrogenation device according to claim 1, characterized in that: The shell side outlet of the raw material preheater is connected to the shell side inlet of the outlet cooler, the shell side outlet of the outlet cooler is connected to the raw material inlet of the first gas-liquid separation tank, and the tube side inlet of the outlet cooler is connected to the cooling water pipeline.

8. The cyclohexane dehydrogenation device according to claim 1, characterized in that: The outlet of the air compressor is connected to the shell side inlet of the gas cooler, the shell side outlet of the gas cooler is connected to the inlet of the second gas-liquid separation tank, and the tube side inlet of the gas cooler is connected to the cooling water pipeline.

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