A waste heat utilization system for a benzene hydrogenation process
By designing a multi-stage heat exchange and preheating system in the benzene hydrogenation process, the thermal energy of the reactor outlet material is used to preheat the production raw materials and hydrogen, and then cooled before high-pressure separation. This solves the problems of low cooling efficiency and unused waste heat, achieving efficient waste heat utilization and cooling, and reducing energy consumption and costs.
Patent Information
- Application Number
- CN202521989311.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-16
- Publication Date
- 2026-08-25
- Estimated Expiration
- 2035-09-16
AI Technical Summary
In the benzene hydrogenation process, the cooling efficiency of the material at the outlet of the main reactor is low, resulting in large heat loss, underutilization of waste heat, increased production costs, and reduced economic benefits.
A waste heat utilization system was designed, which includes equipment such as a vaporizer, a heating furnace, a reactor, a heat exchanger, a hydrogen preheater, a cooler, and a steam generator. Through multi-stage heat exchange and preheating processes, the heat energy of the material at the reactor outlet is used to preheat the production raw materials and hydrogen, reducing the heat loss of the hydrogenated material and effectively cooling it before high-pressure separation.
It improves waste heat utilization, reduces production energy consumption, saves water resources, reduces production costs, and improves cooling efficiency, resulting in good economic benefits.
Smart Images
Figure CN224681282U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of waste heat utilization equipment for benzene hydrogenation process, specifically to a waste heat utilization system for benzene hydrogenation process. Background Technology
[0002] In the benzene hydrogenation process, crude benzene is used as raw material. Through hydrogenation, desulfurization, and denitrification processes, high-purity benzene, toluene, and xylene are produced. There are two hydrogenation reactors: a pre-reactor and a main reactor. The bed temperature in the pre-reactor reaches 190℃, and the bed temperature in the main reactor reaches 280℃. The hydrogenated material enters a high-pressure separator to separate hydrogen gas. Then, after light components are removed in a stabilization tower, hydrogenated oil is produced and sent to the intermediate tank area. In this process, the temperature of the hydrogenated material exiting the main reactor needs to be reduced to below 40℃ when entering the high-pressure separator. Often, cooling is achieved solely with circulating water, resulting in significant energy consumption and heat loss, low cooling efficiency, and a substantial increase in production costs, reducing the company's economic benefits. Furthermore, the waste heat generated during the cooling process is not fully utilized, leading to resource waste. Therefore, developing a waste heat utilization system for the benzene hydrogenation process with low heat loss, high cooling efficiency, and high waste heat utilization rate is objectively necessary. Utility Model Content
[0003] The purpose of this invention is to provide a waste heat utilization system for the benzene hydrogenation process, which has low heat loss, high cooling efficiency, and high waste heat utilization rate.
[0004] The purpose of this utility model is achieved as follows: it includes a vaporizer, a heater, and a reactor connected in sequence. A first heat exchanger is installed on the pipeline at the inlet end of the vaporizer, and a second heat exchanger is installed on the pipeline between the vaporizer and the heater. A hydrogen preheater, a cooler, and a high-pressure separator are installed on the outside of the reactor. The product outlet of the reactor is connected to the second heat exchanger and the hydrogen preheater through pipelines respectively. The product outlet of the second heat exchanger is connected to the first heat exchanger through a pipeline. The product outlets of the first heat exchanger and the hydrogen preheater are connected to the cooler through pipelines respectively. The product outlet of the cooler is connected to the high-pressure separator through a pipeline. The product outlet of the hydrogen preheater is connected to the cooler through a pipeline. The hydrogen outlet of the hydrogen preheater is connected to the reactor through a pipeline.
[0005] Furthermore, a heater is installed on the pipeline between the hydrogen outlet of the hydrogen preheater and the reactor.
[0006] Furthermore, a jacket is provided on the outer wall of the heater, and a hydrogen inlet and a hydrogen outlet are provided on the jacket. The hydrogen outlet is connected to the hydrogen inlet of the hydrogen preheater through a pipeline.
[0007] Furthermore, a product mixer is installed on the outside of the cooler. The product outlet of the first heat exchanger and the product outlet of the hydrogen preheater are respectively connected to the inlet of the product mixer through pipelines, and the outlet of the product mixer is connected to the cooler through pipelines.
[0008] Furthermore, a steam generator is installed on the outside of the cooler, and a water cooler is connected to the gas outlet of the reactor. The hot water outlet of the water cooler and the hot water outlet of the cooler are respectively connected to the inlet of the steam generator through pipelines.
[0009] Furthermore, the gas outlet of the water cooler is connected to a hydrogen recovery device, and the hydrogen outlet of the hydrogen recovery device is connected to the hydrogen inlet of the hydrogen preheater via a pipeline.
[0010] This invention relates to the utilization of waste heat in the benzene hydrogenation process. During operation, the raw materials sequentially enter the first heat exchanger, vaporizer, second heat exchanger, and heater, gradually increasing their temperature until the heater reaches the required temperature. The raw materials are then fed into the reactor to participate in the hydrogenation reaction. The hydrogenated material exiting the reactor is divided into two streams. One stream is sequentially fed into the second heat exchanger and the first heat exchanger to heat the raw materials, while the other stream is fed into a hydrogen preheater to heat the hydrogen. Subsequently, the two hydrogenated materials are combined and fed into a cooler for final cooling. After cooling, the material is sent to a high-pressure separator for subsequent production processes. This invention fully utilizes the thermal energy of the hydrogenated material at the reactor outlet to preheat the raw materials and hydrogen, reducing heat loss of the hydrogenated material, improving waste heat utilization, and increasing the reaction efficiency of the raw materials and hydrogen in the reactor. This significantly reduces production energy consumption and has good economic benefits. Secondly, before entering the high-pressure separator, the hydrogenated material is effectively cooled by the raw materials and hydrogen, significantly reducing its temperature. The subsequent cooling of the hydrogenated material by a cooler improves cooling efficiency and reduces the amount of cooling water used in the cooler, saving water resources and lowering production costs. In summary, this invention has the advantages of low heat loss, high cooling efficiency, and high waste heat utilization. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of the overall structure of this utility model; In the diagram: 1-Vaporizer, 2-Heating furnace, 3-Reactor, 4-First heat exchanger, 5-Second heat exchanger, 6-Hydrogen preheater, 7-Cooler, 8-High pressure separator, 9-Heater, 10-Jacket, 11-Product mixer, 12-Steam generator, 13-Water cooler, 14-Hydrogen recovery device. Detailed Implementation
[0012] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.
[0013] like Figure 1 As shown, this utility model includes a vaporizer 1, a heater 2, and a reactor 3 connected in sequence. The vaporizer 1, heater 2, and reactor 3 are all existing equipment. The vaporizer 1 is used to vaporize the production raw materials, the heater 2 is used to heat the production raw materials, and the reactor 3 is used for the reaction of the production raw materials and hydrogen. A first heat exchanger 4 is installed on the pipeline at the inlet end of the vaporizer 1, and a second heat exchanger 5 is installed on the pipeline between the vaporizer 1 and the heater 2. A hydrogen preheater 6 and a cooler 7 are installed on the outside of the reactor 3. The product outlets of the high-pressure separator 8 and reactor 3 are connected via pipelines to the second heat exchanger 5 and hydrogen preheater 6, respectively. The product outlet of the second heat exchanger 5 is connected via a pipeline to the first heat exchanger 4. The product outlets of the first heat exchanger 4 and the hydrogen preheater 6 are connected via pipelines to the cooler 7, respectively. The product outlet of the cooler 7 is connected via a pipeline to the high-pressure separator 8, the product outlet of the hydrogen preheater 6 is connected via a pipeline to the cooler 7, and the hydrogen outlet of the hydrogen preheater 6 is connected via a pipeline to the reactor 3. The first heat exchanger 4, the second heat exchanger 5, the hydrogen preheater 6, and the cooler 7 are all existing heat exchanger structures; shell-and-tube heat exchangers or other structural forms can be selected.
[0014] This invention relates to the utilization of waste heat in the benzene hydrogenation process. During operation, the raw materials are sequentially fed into the first heat exchanger 4, the vaporizer 1, the second heat exchanger 5, and the heater 2, gradually increasing their temperature until the heater 2 raises it to the required temperature. The raw materials are then fed into the reactor 3 to participate in the hydrogenation reaction. The hydrogenated material exiting the reactor 3 is divided into two streams. One stream is sequentially fed into the second heat exchanger 5 and the first heat exchanger 4 to heat the raw materials, while the other stream is fed into the hydrogen preheater 6 to heat the hydrogen. Subsequently, the two hydrogenated materials are combined and fed into the cooler 7 for final cooling. After cooling, the materials are sent to the high-pressure separator 8 for subsequent production processes.
[0015] This invention fully utilizes the thermal energy of the hydrogenated substance at the outlet of reactor 3 to preheat the raw materials and hydrogen, reducing heat loss of the hydrogenated substance, improving the utilization rate of waste heat, increasing the reaction efficiency of the raw materials and hydrogen in the reactor, and significantly reducing production energy consumption, resulting in good economic benefits. Secondly, before entering the high-pressure separator 8, the hydrogenated substance is first cooled by the raw materials and hydrogen, significantly reducing its temperature. Then, the hydrogenated substance is cooled by the cooler 7, which can improve the cooling efficiency of the hydrogenated substance and reduce the amount of cooling water used in the cooler 7, saving water resources and reducing production costs.
[0016] A heater 9 is installed on the pipeline between the hydrogen outlet of the hydrogen preheater 6 and the reactor 3. The heater 9 is an existing gas heating device and can adopt an electric heating structure. In the initial stage of equipment operation or when there are fluctuations in the production process, the preheating temperature of hydrogen may not meet the requirements. At this time, hydrogen can be introduced into the heater 9 for heating to ensure the reaction temperature requirements after hydrogen is introduced into the reactor 3.
[0017] A jacket 10 is provided on the outer wall of the heater 9. The jacket 10 is provided with a hydrogen inlet and a hydrogen outlet. The hydrogen outlet is connected to the hydrogen inlet of the hydrogen preheater 6 through a pipeline. The heater 9 is used to heat the hydrogen. In actual operation, the surface of the heater 9 will emit a certain amount of heat, resulting in heat loss. In order to avoid this problem, a jacket 10 is provided on the outer wall of the heater 9. Cold hydrogen is introduced into the jacket 10, which can absorb the heat lost by the heater 9, reduce heat waste, and preheat the cold hydrogen.
[0018] A product mixer 11 is provided on the outside of the cooler 7. The product outlet of the first heat exchanger 4 and the product outlet of the hydrogen preheater 6 are respectively connected to the inlet of the product mixer 11 through pipelines. The outlet of the product mixer 11 is connected to the cooler 7 through a pipeline. In this invention, there are two streams of hydrogenated substances introduced into the cooler 7, one from the first heat exchanger 4 and the other from the hydrogen preheater 6. In actual operation, the temperatures of the two streams of hydrogenated substances have a certain difference. Directly introducing them into the cooler 7 may reduce the cooling effect of the cooler 7 due to large temperature fluctuations. To avoid this problem, the product mixer 11 is provided to mix the two streams of hydrogenated substances, so that the hydrogenated substances have a more stable temperature when they are sent into the cooler 7, thereby improving the cooling effect of the cooler 7.
[0019] A steam generator 12 is installed on the outside of the cooler 7. The gas outlet of the reactor 3 is connected to a water cooler 13. The hot water outlet of the water cooler 13 and the hot water outlet of the cooler 7 are respectively connected to the inlet of the steam generator 12 through pipelines. The steam generator 12, the water cooler 13 and the cooler 7 are all existing equipment. The steam generator 12 is used to produce saturated steam. The water cooler 13 and the cooler 7 are existing heat exchange equipment. In this utility model, the mixture of unreacted hydrogen and other gases is discharged from the gas outlet of the reactor 3 and passed into the water cooler 13. The cooling water absorbs the heat in the mixture. Similarly, the hydrogenated substance discharged from the reactor 3 passes through the second heat exchanger 5 and the first heat exchanger 4 in sequence and then passes into the cooler 7. The cooling water absorbs the heat in the hydrogenated substance. In both of the above processes, hot water with a certain temperature can be generated. Passing it into the steam generator 12 can reduce the energy consumption of steam production and has the effect of energy saving and consumption reduction.
[0020] The gas outlet of the water cooler 13 is connected to a hydrogen recovery device 14. The hydrogen recovery device 14 is an existing mature process equipment used to remove organic substances such as benzene and cyclohexane from the gas and improve the purity of hydrogen. The hydrogen outlet of the hydrogen recovery device 14 is connected to the hydrogen inlet of the hydrogen preheater 6 through a pipeline. In the crude benzene hydrogenation process, excess hydrogen is usually used to ensure sufficient reaction. Therefore, the discharged gas often contains unreacted hydrogen. The hydrogen recovery device 14 recovers and utilizes the hydrogen, reducing hydrogen consumption and production costs.
Claims
1. A waste heat utilization system for a benzene hydrogenation process, comprising a vaporizer (1), a heater (2), and a reactor (3) connected in sequence, characterized in that: A first heat exchanger (4) is installed on the pipeline at the inlet end of the vaporizer (1), and a second heat exchanger (5) is installed on the pipeline between the vaporizer (1) and the heating furnace (2). A hydrogen preheater (6), a cooler (7) and a high-pressure separator (8) are installed on the outside of the reactor (3). The product outlet of the reactor (3) is connected to the second heat exchanger (5) and the hydrogen preheater (6) through pipelines respectively. The product outlet of the second heat exchanger (5) is connected to the first heat exchanger (4) through pipelines. The product outlet of the first heat exchanger (4) and the product outlet of the hydrogen preheater (6) are connected to the cooler (7) through pipelines respectively. The product outlet of the cooler (7) is connected to the high-pressure separator (8) through pipelines. The product outlet of the hydrogen preheater (6) is connected to the cooler (7) through pipelines. The hydrogen outlet of the hydrogen preheater (6) is connected to the reactor (3) through pipelines.
2. The waste heat utilization system for a benzene hydrogenation process according to claim 1, characterized in that: A heater (9) is installed on the pipeline between the hydrogen outlet of the hydrogen preheater (6) and the reactor (3).
3. The waste heat recovery system for a benzene hydrogenation process according to claim 2, characterized in that: The heater (9) is provided with a jacket (10) on its outer wall. The jacket (10) is provided with a hydrogen inlet and a hydrogen outlet. The hydrogen outlet is connected to the hydrogen inlet of the hydrogen preheater (6) through a pipeline.
4. The waste heat recovery system for a benzene hydrogenation process according to claim 1, characterized in that: A product mixer (11) is provided on the outside of the cooler (7). The product outlet of the first heat exchanger (4) and the product outlet of the hydrogen preheater (6) are respectively connected to the inlet of the product mixer (11) through pipelines. The outlet of the product mixer (11) is connected to the cooler (7) through pipelines.
5. The waste heat recovery system for a benzene hydrogenation process according to claim 1, characterized in that: A steam generator (12) is provided on the outside of the cooler (7), and a water cooler (13) is connected to the gas outlet of the reactor (3). The hot water outlet of the water cooler (13) and the hot water outlet of the cooler (7) are respectively connected to the inlet of the steam generator (12) through pipelines.
6. The waste heat recovery system for a benzene hydrogenation process according to claim 5, characterized in that: The gas outlet of the water cooler (13) is connected to a hydrogen recovery device (14), and the hydrogen outlet of the hydrogen recovery device (14) is connected to the hydrogen inlet of the hydrogen preheater (6) via a pipeline.