A system for utilizing the reaction heat of propionaldehyde hydrogenation

Abstract

The present invention discloses a system for utilizing the reaction heat of propionaldehyde hydrogenation, which includes a circulating hot water tank, a circulating hot water pump, an auxiliary cooler, a propanol heat exchanger, a propionaldehyde hydrogenation reactor, a hot water heater, a first heat exchanger, a second heat exchanger, a circulating hot water air cooler, an auxiliary heater and a hot water pump; the circulating hot water tank is connected to the circulating hot water pump, and the circulating hot water pump is respectively connected to the auxiliary cooler, the propanol heat exchanger, the propionaldehyde hydrogenation reactor and the hot water heater; the propionaldehyde hydrogenation reactor is respectively connected to the hot water heater and the circulating hot water air cooler, and the circulating hot water air cooler is connected to the circulating hot water pump; the hot water heater is respectively connected to the first heat exchanger, the second heat exchanger and the circulating hot water tank, and the first heat exchanger and the second heat exchanger are connected to the circulating hot water tank; a circulating water circuit is formed between the circulating water heater, the hot water pump and the auxiliary heater. The system of the present invention is effectively combined to enable the system to be unaffected under abnormal conditions where the reaction heat of propionaldehyde hydrogenation is small or stopped.

Description

Technical Field

[0001] The present invention belongs to the technical field of reaction heat utilization, and particularly relates to a system for utilizing the reaction heat of propionaldehyde hydrogenation. Background Art

[0002] The propionaldehyde hydrogenation reaction is an important way to synthesize propanol, which is completed in a hydrogenation reactor. The mixed system of propionaldehyde and hydrogen enters from the bottom of the reactor after preheating and vaporization, and passes through the catalyst bed layer from bottom to top under the push of the pressure difference, and proceeds under certain high-temperature conditions to complete the polycondensation to produce propanol. During the process of producing propanol by propionaldehyde hydrogenation, the heat generated in the hydrogenation reactor needs to be removed. Currently, generally, circulating water or an air cooler is used to remove the heat in the circulating hot water.

[0003] The above equipment and processes have the problem of heat waste, and at the same time increase the production cost of the product, indirectly resulting in an increase in cost. Currently, there is a way to directly utilize the reaction heat of propionaldehyde hydrogenation in a propionaldehyde evaporator and a hot water heater, which can realize the utilization of the reaction heat of propionaldehyde hydrogenation. However, this system is highly dependent on equipment. Once a certain equipment is damaged or production stops, the operation of other equipment will also have problems. Summary of the Invention

[0004] Aiming at the problems of waste of reaction heat resources in propionaldehyde hydrogenation and high dependence between equipment in the prior art, the present invention provides a system for utilizing the reaction heat of propionaldehyde hydrogenation, which realizes the efficient combination of the system, so that under abnormal conditions where the reaction heat of propionaldehyde hydrogenation is small or stops, the system can operate well without being affected.

[0005] The present invention is realized through the following technical solutions:

[0006] A system for utilizing the reaction heat of propionaldehyde hydrogenation includes a circulating hot water tank, a circulating hot water pump, an auxiliary cooler, a propanol heat exchanger, a propionaldehyde hydrogenation reactor, a hot water heater, a first heat exchanger, a second heat exchanger, a circulating hot water air cooler, an auxiliary heater, and a hot water pump;

[0007] The outlet of the circulating hot water tank is connected to the inlet of the circulating hot water pump, and the outlet of the circulating hot water pump is respectively connected to the inlets of the auxiliary cooler, the propanol heat exchanger, the propionaldehyde hydrogenation reactor, and the hot water heater;

[0008] The outlet of the propionaldehyde hydrogenation reactor is respectively connected to the inlets of the hot water heater and the circulating hot water air cooler, and the outlet of the circulating hot water air cooler is connected to the inlet of the circulating hot water tank;

[0009] The outlet of the hot water heater is respectively connected to the inlets of the first heat exchanger, the second heat exchanger, and the circulating hot water tank, and the outlets of the first heat exchanger and the second heat exchanger are connected to the inlet of the circulating hot water tank;

[0010] The water outlets of the described auxiliary cooler and propanol heat exchanger are respectively connected to the inlets of the first heat exchanger and the second heat exchanger;

[0011] A circulating water loop is formed between the described circulating hot water tank, hot water pump and auxiliary heater to keep the water temperature in the circulating hot water tank constant.

[0012] Furthermore, regulating valves are provided in front of each device to control the water inflow and the flow direction of the outlet water.

[0013] Furthermore, the water outlets of the propanol heat exchanger and the propionaldehyde hydrogenation reactor are combined and then enter the first heat exchanger and the second heat exchanger respectively.

[0014] Furthermore, the water outlets of the first heat exchanger and the second heat exchanger are combined with the remaining hot water from the hot water heater and then enter the circulating hot water tank.

[0015] Furthermore, there are two circulating hot water pumps, one in operation and one in standby.

[0016] Furthermore, the propionaldehyde hydrogenation reaction heat utilization system is controlled by DSC.

[0017] Furthermore, during normal operation, the loads of the hot water heater and the circulating hot water air cooler are both zero.

[0018] Beneficial effects

[0019] (1) The propionaldehyde hydrogenation reaction heat utilization system in the present invention can save 8 tons of 0.5 MPa low-pressure steam per hour. At the same time, the circulating hot water air cooler is shut down, saving 45 KW of motor operation energy consumption per hour. The reaction heat is utilized on the device equipment, achieving a perfect combination of reaction heat and heat-requiring equipment;

[0020] (2) The effective combination of the propionaldehyde hydrogenation reaction heat utilization system in the present invention enables the system to operate well without being affected under abnormal conditions where the propionaldehyde hydrogenation reaction heat is small or stopped. Brief description of the drawings

[0021] Figure 1 It is a schematic diagram of the propionaldehyde hydrogenation reaction heat utilization system;

[0022] Among them, 1. Circulating hot water tank, 2. Circulating hot water pump, 3. Auxiliary cooler, 4. Propanol heat exchanger, 5. Propionaldehyde hydrogenation reactor, 6. Hot water heater, 7. First heat exchanger, 8. Second heat exchanger, 9. Circulating hot water air cooler, 10. Auxiliary heater, 11. Hot water pump. Specific embodiments

[0023] To better understand the present invention, the propionaldehyde hydrogenation reaction heat utilization system will be described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0024] The propionaldehyde hydrogenation reaction heat utilization system in the present invention is as Figure 1 shown: It can be seen from Figure 1 that the propionaldehyde hydrogenation reaction heat utilization system in the present invention includes a circulating hot water tank 1, a circulating hot water pump 2 (two, one running and one standby), an auxiliary cooler 3, a propanol heat exchanger 4, a propionaldehyde hydrogenation reactor 5, a hot water heater 6, a first heat exchanger 7, a second heat exchanger 8, a circulating hot water air cooler 9, an auxiliary heater 10, and a hot water pump 11; the outlet of the circulating hot water tank 1 is connected to the inlet of the circulating hot water pump 2, and the outlet of the circulating hot water pump 2 is respectively connected to the inlets of the auxiliary cooler 3, the propanol heat exchanger 4, the propionaldehyde hydrogenation reactor 5, and the hot water heater 6; the outlet of the propionaldehyde hydrogenation reactor 5 is respectively connected to the inlets of the hot water heater 6 and the circulating hot water air cooler 9, and the outlet of the circulating hot water air cooler 9 is connected to the inlet of the circulating hot water tank 1; the outlet of the hot water heater 6 is respectively connected to the inlets of the first heat exchanger 7, the second heat exchanger 8, and the circulating hot water tank 1, and the outlets of the first heat exchanger 7 and the second heat exchanger 8 are connected to the inlet of the circulating hot water tank 1; the water outlets of the auxiliary cooler 3 and the propanol heat exchanger 4 are respectively connected to the inlets of the first heat exchanger 7 and the second heat exchanger 8; a circulating water loop is formed between the circulating hot water tank 1, the hot water pump 11, and the auxiliary heater 10 to keep the water temperature in the circulating hot water tank 1 constant.

[0025] Regulating valves are provided on the pipelines between the circulating hot water tank 1 and the auxiliary cooler 3, the propanol heat exchanger 4, the propionaldehyde hydrogenation reactor 5, and the hot water heater 7 to control the flow direction of the water flowing out of the circulating hot water tank 1; regulating valves are provided on the pipelines between the auxiliary heater 6 and the first heat exchanger 7 and the second heat exchanger 8 to control the flow direction of the water flowing out of the auxiliary heater 7; the water outlets of the propanol heat exchanger 4 and the propionaldehyde hydrogenation reactor 5 are aggregated and then enter the first heat exchanger 7 and the second heat exchanger 8 respectively, and regulating valves are provided between the first heat exchanger 7 and the second heat exchanger 8.

[0026] The propionaldehyde hydrogenation reaction heat utilization system is controlled by a DSC system to control the inlet water flow rate, inlet water temperature, and operating load of each device.

[0027] Now, the usage method of the propionaldehyde hydrogenation reaction heat utilization system in the present invention will be described in conjunction with specific embodiments.

[0028] Example 1

[0029] Set the water flow direction between each device, where:

[0030] Stream 1: Hot water from the outlet of the circulating hot water pump 2;

[0031] Stream 2: Hot water from the outlet of the auxiliary cooler 3;

[0032] Stream 3: Hot water from the outlet of the propanol heat exchanger 4;

[0033] Stream 4: Hot water from the outlet of the propionaldehyde hydrogenation reactor 5;

[0034] Stream 5: Remaining hot water;

[0035] Stream 6: Hot water entering the first heat exchanger 7;

[0036] Stream 7: Hot water entering the second heat exchanger 8;

[0037] Stream 8: Hot water returning to the circulating hot water tank 1;

[0038] Stream 9: Hot water going to the circulating hot water air cooler 9;

[0039] Stream 10: Hot water from the outlet of the first heat exchanger 7;

[0040] Stream 11: Hot water from the outlet of the second heat exchanger 8;

[0041] Stream 12: Hot water before entering the propanol heat exchanger 12;

[0042] Stream 13: Hot water before entering the auxiliary cooler 13;

[0043] At the start of operation:

[0044] The circulating hot water tank 1 stores a certain amount of hot water. The control valves before the circulating hot water pump 2 and each equipment are started. The circulating hot water flows through the circulating hot water pump 2, the propionaldehyde hydrogenation reactor 5 and the hot water heater 6, and finally returns to the circulating hot water tank 1. Through the auxiliary heater 10, the water temperature in the circulating hot water tank 1 is controlled at about 104 °C, and at the same time, the propionaldehyde hydrogenation reactor 5 is preheated to about 100 °C for easy start-up;

[0045] During normal operation:

[0046] (1) By controlling the control valves before each equipment, the hot water in the circulating hot water tank 1 enters the auxiliary heater 10 through the hot water pump 11 to be Stream 2. The temperature of the hot water in the circulating hot water tank 1 is controlled between 104 - 106 °C through the auxiliary heater 10. When the hot water at this temperature enters the propionaldehyde hydrogenation reactor 5 to remove heat, the side reactions are lower, the heavy components such as propyl propionate generated are lower, and the conversion rate of the propionaldehyde hydrogenation reaction is higher;

[0047] (2) By controlling the regulating valves in front of each device, the hot water in the circulating hot water tank 1 enters the propionaldehyde hydrogenation reactor 5. After passing through the propionaldehyde hydrogenation reactor 5, the temperature rises to 120 °C, forming the hot water after the propionaldehyde hydrogenation reactor 5 (stream 4);

[0048] (3) By controlling the regulating valves in front of each device, the hot water (stream 12) in the circulating hot water tank 1 enters the propanol heat exchanger 4. After heating the propanol heat exchanger 4, the temperature drops to 85 °C, forming the cold water after exiting the propanol heat exchanger 4 (stream 3);

[0049] (4) By controlling the regulating valves in front of each device, the hot water (stream 13) in the circulating hot water tank 1 enters the auxiliary cooler 3. After being cooled by the auxiliary cooler 3, the temperature drops to 85 °C, forming the cold water after exiting the auxiliary cooler (stream 2);

[0050] (5) The hot water discharged from the propionaldehyde hydrogenation reactor 5 (stream 4), the cold water after the propanol heat exchanger 4 (stream 3), and the cold water after the auxiliary cooler (stream 2) converge. Then, part of the hot water in the hot water heater 6 and the cold water enter the first heat exchanger 7 and the second heat exchanger 8. By means of the control valves before the first heat exchanger 7 and the second heat exchanger 8, the temperatures of the hot water entering the first heat exchanger 7 (stream 6) and the first heat exchanger 8 (stream 7) are controlled at 106 - 107 °C; after passing through the first heat exchanger, the temperature of (stream 10) drops to 94 °C, and after passing through the second heat exchanger, the temperature of (stream 11) drops to 89 °C. The hot water exiting the first heat exchanger 7 and the second heat exchanger 8 converges with the remaining hot water from the hot water heater 6 and then returns to the circulating hot water tank 1. Through actual operation, it is confirmed that when the temperature of the hot water entering the first heat exchanger 7 and the second heat exchanger 8 is controlled between 106 - 109 °C, the temperature of the hot water exiting the first heat exchanger 7 is controlled between 90 - 96 °C, and the temperature of the hot water exiting the second heat exchanger is controlled between 85 - 92 °C, the heat exchange efficiency of the first heat exchanger and the second heat exchanger is relatively high;

[0051] The temperature of the circulating hot water passing through the above-mentioned equipment and pipelines is constantly controlled at 104 ± 0.5 °C in the circulating hot water tank, and the loads of the circulating hot water air cooler 10 and the hot water heater 7 are both zero.

[0052] Using the above propionaldehyde hydrogenation reaction heat utilization system, the flow rate entering the circulating hot water pump is 335000 kg / h. 8 tons of 0.5 MPa low-pressure steam can be saved per hour. At the same time, the circulating hot water air cooler 9 has zero load, and the motor operation energy consumption of 45 KW can be saved per hour. The reaction heat is utilized on the device equipment, realizing the perfect combination of the reaction heat and the heat-requiring equipment.

[0053] During abnormal operating conditions:

[0054] (1) The heat release of the propionaldehyde hydrogenation reactor 5 suddenly stops, and the auxiliary heater 10 starts to operate, heating the hot water from the circulating hot water tank 1 to maintain the normal operation of the device.

[0055] (2) The first heat exchanger 7 and the second heat exchanger 8 suddenly stop operating. When no heat is required, the circulating hot water air cooler 9 is started. The hot water (stream 4) heated by the propionaldehyde hydrogenation reactor 5 directly enters the circulating hot water air cooler 9 and then enters the circulating hot water tank 1. The temperature of the circulating hot water tank 1 is controlled at 104 ± 0.5 °C to maintain the normal operation of the device.

[0056] Although the specific embodiments of the present invention have been described in conjunction with the accompanying drawings above, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made without creative efforts by those skilled in the art are still within the protection scope of the present invention.

Claims

1. A propionaldehyde hydrogenation reaction heat utilization system, characterized in that, It includes a circulating hot water tank (1), a circulating hot water pump (2), an auxiliary cooler (3), a propanol heat exchanger (4), a propionaldehyde hydrogenation reactor (5), a hot water heater (6), a first heat exchanger (7), a second heat exchanger (8), a circulating hot water air cooler (9), an auxiliary heater (10) and a hot water pump (11); The outlet of the circulating hot water tank (1) is connected to the inlet of the circulating hot water pump (2), and the outlet of the circulating hot water pump (2) is respectively connected to the inlets of the auxiliary cooler (3), the propanol heat exchanger (4), the propionaldehyde hydrogenation reactor (5) and the hot water heater (6); The outlet of the propionaldehyde hydrogenation reactor (5) is respectively connected to the inlets of the hot water heater (6) and the circulating hot water air cooler (9), and the outlet of the circulating hot water air cooler (9) is connected to the inlet of the circulating hot water tank (1); The outlet of the hot water heater (6) is respectively connected to the inlets of the first heat exchanger (7), the second heat exchanger (8) and the circulating hot water tank (1), and the outlets of the first heat exchanger (7) and the second heat exchanger (8) are connected to the inlet of the circulating hot water tank (1); The water outlets of the auxiliary cooler (3) and the propanol heat exchanger (4) are respectively connected to the inlets of the first heat exchanger (7) and the second heat exchanger (8); A circulating water circuit is formed between the circulating hot water tank (1), the hot water pump (11) and the auxiliary heater (10) to keep the water temperature in the circulating hot water tank (1) constant.

2. The propionaldehyde hydrogenation reaction heat utilization system according to claim 1, characterized in that, A regulating valve is provided in front of each device to control the water inflow and the water flow direction.

3. The propionaldehyde hydrogenation reaction heat utilization system according to claim 1, characterized in that, The water outlets of the propanol heat exchanger (4) and the propionaldehyde hydrogenation reactor (5) are combined and then enter the first heat exchanger (7) and the second heat exchanger (8) respectively.

4. The propionaldehyde hydrogenation reaction heat utilization system according to claim 1, characterized in that The water outlets of the first heat exchanger (7) and the second heat exchanger (8) are combined with the remaining hot water from the hot water heater (6) and then enter the circulating hot water tank (1).

5. The propionaldehyde hydrogenation reaction heat utilization system according to claim 1, characterized in that, There are two circulating hot water pumps (2), one in operation and one in standby.

6. The propionaldehyde hydrogenation reaction heat utilization system according to claim 1, wherein The propionaldehyde hydrogenation reaction heat utilization system is controlled by DSC.

7. The propionaldehyde hydrogenation reaction heat utilization system according to claim 1, characterized in that During normal operation, the loads of the hot water heater (6) and the circulating hot water air cooler (9) are both zero.

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