Waste heat utilization system for furfural production

Abstract

The utility model discloses a waste heat utilization system for furfural production, which comprises a hydrolysis kettle, a pure water evaporator, a furfural primary tower, a furfural dehydrating tower and a furfural rectifying tower are sequentially arranged on a pipeline at the rear end of the hydrolysis kettle, and a first sucking pump is arranged on a pipeline between the hydrolysis kettle and the pure water evaporator; a heat exchanger is arranged on a gas outlet pipeline of the pure water evaporator, two heat exchange pipelines are arranged on the heat exchanger, the first heat exchange pipeline is respectively connected with steam inlets of the furfural primary distillation tower, the furfural dehydration tower and the furfural rectifying tower, the second heat exchange pipeline is connected with a drying tower, and a second sucking pump is arranged on the first heat exchange pipeline; a third sucking pump is arranged on the second heat exchange pipeline; the system further comprises a PLC (Programmable Logic Controller). According to the utility model, after passing through the heat exchanger, high-temperature gas subjected to gas-liquid separation participates in the subsequent production process of furfural on one hand, and participates in the drying of furfural raw materials on the other hand, so that the recycling of high-temperature waste heat is realized, and the utilization rate of resources is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of furfural production, and more specifically to a waste heat utilization system for furfural production. Background Art

[0002] Furfural is an industrial chemical that can be extracted from a variety of agricultural byproducts, including corn cobs, oat and wheat bran, and sawdust.

[0003] In the process of furfural processing, the corn cob raw material needs to be broken up by a crusher, and the broken raw material is mixed with dilute sulfuric acid to achieve acid mixing. The corn cob raw material after acid mixing enters a hydrolysis kettle, and high-temperature steam is introduced into the hydrolysis kettle to hydrolyze the corn cob after acid mixing, so that aldehyde gas is generated in the hydrolysis kettle, and the aldehyde gas enters the primary distillation tower for distillation, so that the furfural content in the aldehyde liquid reaches 92%. The aldehyde liquid is dehydrated in a dehydration tower and sent to a distillation tower for refining, and finally the finished furfural is obtained.

[0004] A large amount of heat energy will be generated in the furfural production technology, but the existing furfural production technology directly discharges this heat energy, which not only causes a waste of resources, but also has a certain adverse impact on the surrounding environment. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a waste heat utilization system for furfural production, which can recover and reuse the heat generated in the furfural production process, improve resource utilization and protect the surrounding environment.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present utility model are as follows.

[0007] A waste heat utilization system for furfural production comprises a hydrolysis kettle for hydrolyzing furfural, a pure water evaporator for distilling aldehyde vapor after hydrolysis, a furfural primary distillation tower, a furfural dehydration tower and a furfural rectification tower are sequentially arranged on the pipeline at the rear end of the hydrolysis kettle, a first vacuum pump for sending the aldehyde vapor after hydrolysis to the subsequent process is arranged on the pipeline between the hydrolysis kettle and the pure water evaporator; a heat exchanger for exchanging the waste heat of steam after gas-liquid separation is arranged on the gas outlet pipeline of the pure water evaporator, and the heat exchanger is used to heat the waste heat of steam after gas-liquid separation. The device is provided with two heat exchange pipes, wherein the first heat exchange pipe is respectively connected to the steam inlet of the furfural primary distillation tower, the furfural dehydration tower and the furfural distillation tower, the second heat exchange pipe is connected to the drying tower for drying the furfural raw material, the first heat exchange pipe is provided with a second vacuum pump, and the second heat exchange pipe is provided with a third vacuum pump; the system also includes a PLC controller for controlling the utilization of waste heat, and the output end of the PLC controller is respectively connected to the input end of the first vacuum pump, the second vacuum pump and the third vacuum pump.

[0008] To further optimize the technical solution, a first heat exchange temperature sensor for detecting the temperature of the gas in the first heat exchange pipe is provided on the first heat exchange pipe, and a second heat exchange temperature sensor for detecting the temperature of the gas in the second heat exchange pipe is provided on the second heat exchange pipe, and the output ends of the first heat exchange temperature sensor and the second heat exchange temperature sensor are respectively connected to the input ends of the PLC controller.

[0009] To further optimize the technical solution, the furfural primary distillation tower is provided with a primary distillation tower temperature sensor for detecting the temperature of gas entering the furfural primary distillation tower, the furfural dehydration tower is provided with a dehydration tower temperature sensor for detecting the temperature of gas entering the furfural dehydration tower, and the furfural distillation tower is provided with a distillation tower temperature sensor for detecting the temperature of gas entering the furfural distillation tower, and the output ends of the primary distillation tower temperature sensor, the dehydration tower temperature sensor and the distillation tower temperature sensor are respectively connected to the input end of the PLC controller.

[0010] To further optimize the technical solution, a first regulating valve for controlling the amount of gas entering is arranged on the pipeline connecting the first heat exchange pipeline and the furfural primary distillation tower, a second regulating valve for controlling the amount of gas entering is arranged on the pipeline connecting the first heat exchange pipeline and the furfural dehydration tower, and a third regulating valve for controlling the amount of gas entering is arranged on the pipeline connecting the first heat exchange pipeline and the furfural distillation tower, and the input ends of the first regulating valve, the second regulating valve and the third regulating valve are respectively connected to the output end of the PLC controller.

[0011] To further optimize the technical solution, a fourth regulating valve for controlling the amount of gas entering the drying tower is provided on the second heat exchange pipeline, and the input end of the fourth regulating valve is connected to the output end of the PLC controller.

[0012] To further optimize the technical solution, a drying box for drying furfural raw materials is provided in the drying tower, a feeding pipe for feeding the drying box is provided above the drying tower, a discharge port for discharging materials is provided at the bottom of the drying tower, a heat conducting sheet for absorbing gas heat is provided on the outer wall of the drying box, an exhaust fan for increasing gas flow is provided on the outer wall of the drying tower, and the input end of the exhaust fan is connected to the output end of the PLC controller.

[0013] To further optimize the technical solution, a stirring shaft is provided inside the drying box, a stirring blade is provided on the stirring shaft, a stirring motor for driving the stirring shaft to rotate is provided on the top of the drying tower, and the input end of the stirring motor is connected to the output end of the PLC controller.

[0014] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0015] The utility model provides a waste heat utilization system for furfural production. After the high-temperature gas after gas-liquid separation passes through a heat exchanger, it participates in the subsequent production process of furfural on the one hand, and participates in the drying of furfural raw materials on the other hand, thereby realizing the recovery and reuse of high-temperature waste heat, thereby improving the utilization rate of resources and protecting the surrounding environment. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 2 It is a structural schematic diagram of a drying box of the utility model.

[0018] Wherein: 1. hydrolysis kettle, 2. pure water evaporator, 3. furfural primary distillation tower, 4. furfural dehydration tower, 5. furfural distillation tower, 6. heat exchanger, 7. drying tower, 71. drying box, 72. feed pipe, 73. stirring motor, 74. stirring shaft, 75. stirring blade, 76. discharge port, 77. heat conductive plate, 78. exhaust fan, 8. first vacuum pump, 9. first heat exchange pipeline, 10. second vacuum pump, 11. first heat exchange temperature sensor, 12. first regulating valve, 13. primary distillation tower temperature sensor, 14. second regulating valve, 15. dehydration tower temperature sensor, 16. third regulating valve, 17. distillation temperature sensor, 18. third vacuum pump, 19. second heat exchange temperature sensor, 20. fourth regulating valve, 21. second heat exchange pipeline. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] A waste heat utilization system for furfural production, combined with Figure 1 to Figure 2 As shown, it includes a hydrolysis kettle 1, a pure water evaporator 2, a furfural primary distillation tower 3, a furfural dehydration tower 4, a furfural distillation tower 5, a heat exchanger 6, a drying tower 7 and a PLC controller. The hydrolysis kettle 1 is used to hydrolyze furfural. The pure water evaporator 2 is arranged on the pipeline at the rear end of the hydrolysis kettle 1 to separate the aldehyde gas after hydrolysis. The furfural primary distillation tower 3, the furfural dehydration tower 4 and the furfural distillation tower 5 are arranged on the liquid pipeline behind the pure water evaporator 2 in sequence to distill the aldehyde liquid after gas-liquid separation, and finally obtain the finished furfural. The heat exchanger 6 is used to heat the gas at the rear end of the pure water evaporator separation. The drying tower 7 is connected to the heat exchange pipeline of the heat exchanger to dry the furfural raw material. The PLC controller is used to control the utilization of waste heat.

[0021] A first vacuum pump 8 is provided on the pipeline between the hydrolysis kettle 1 and the pure water evaporator 2 to deliver the hydrolyzed aldehyde vapor into the pure water evaporator for subsequent treatment. The input end of the first vacuum pump is connected to the output end of the PLC controller.

[0022] The heat exchanger 6 is arranged on the gas outlet pipe of the pure water evaporator 2, and two heat exchange pipes are arranged on the heat exchanger 6, wherein the first heat exchange pipe 9 is respectively connected to the steam inlet of the furfural primary distillation tower 3, the furfural dehydration tower 4 and the furfural distillation tower 5, and is used to heat the furfural primary distillation tower 3, the furfural dehydration tower 4 and the furfural distillation tower 5 with the heat exchanged gas; the second heat exchange pipe 21 is connected to the air inlet pipe of the drying tower 7, and is used to heat the drying tower with the heat exchanged gas. The first heat exchange pipe 9 is provided with a second vacuum pump 10, which is used to send the heat exchanged gas into the furfural primary distillation tower, the furfural dehydration tower and the furfural distillation tower, and the second heat exchange pipe 21 is provided with a third vacuum pump 18, which is used to send the heat exchanged gas into the drying tower, and the input ends of the second vacuum pump and the third vacuum pump are respectively connected to the output end of the PLC controller.

[0023] A first heat exchange temperature sensor 11 is provided on the first heat exchange pipe 9 for detecting the gas temperature in the first heat exchange pipe. A second heat exchange temperature sensor 19 is provided on the second heat exchange pipe 21 for detecting the gas temperature in the second heat exchange pipe. The output ends of the first heat exchange temperature sensor and the second heat exchange temperature sensor are respectively connected to the input end of the PLC controller.

[0024] A primary distillation tower temperature sensor 13 is provided on the furfural primary distillation tower 3 to detect the temperature of the gas entering the furfural primary distillation tower. A dehydration tower temperature sensor 15 is provided on the furfural dehydration tower 4 to detect the temperature of the gas entering the furfural dehydration tower. A distillation tower temperature sensor 17 is provided on the furfural distillation tower 5 to detect the temperature of the gas entering the distillation tower. The output ends of the primary distillation tower temperature sensor, the dehydration tower temperature sensor and the distillation tower temperature sensor are respectively connected to the input ends of the PLC controller.

[0025] A first regulating valve 12 is provided on the pipeline connecting the first heat exchange pipeline 9 and the furfural primary distillation tower 3, for controlling the amount of gas entering the furfural primary distillation tower; a second regulating valve 14 is provided on the pipeline connecting the first heat exchange pipeline 9 and the furfural dehydration tower 4, for controlling the amount of gas entering the furfural dehydration tower; a third regulating valve 16 is provided on the pipeline connecting the first heat exchange pipeline 9 and the furfural distillation tower 5, for controlling the amount of gas entering the furfural distillation tower; the input ends of the first regulating valve, the second regulating valve and the third regulating valve are respectively connected to the output end of the PLC controller.

[0026] A fourth regulating valve 20 is provided on the second heat exchange pipe 21 for controlling the amount of gas entering the drying tower. The output end of the fourth regulating valve is connected to the input end of the PLC controller.

[0027] A drying box 71 is provided in the drying tower 7 for drying the furfural raw material. A feed pipe 72 is provided above the drying tower 7, and the feed pipe is connected to the drying box for feeding the drying box. A discharge port 76 is provided at the bottom of the drying tower 7 for discharging the dried furfural raw material. A heat conducting sheet 77 is provided on the outer wall of the drying box 71 for absorbing the heat of the gas. An exhaust fan 78 is provided on the outer wall of the drying tower 7 for accelerating the gas flow, increasing the temperature of the drying box, and thus improving the drying effect of the furfural raw material. The input end of the exhaust fan is connected to the output end of the PLC controller.

[0028] A stirring shaft 74 is provided inside the drying box 71, and a stirring blade 75 is provided on the stirring shaft. A stirring motor 73 is provided above the drying tower 7, and the stirring motor is connected to the stirring shaft. The stirring blade is driven by the stirring shaft to rotate and stir the furfural raw material in the drying box, so that the furfural raw material is heated more evenly and the drying efficiency is improved. The input end of the stirring motor is connected to the output end of the PLC controller.

[0029] The high-temperature aldehyde gas generated during the hydrolysis process of the hydrolysis kettle of the utility model enters into a pure water evaporator for gas-liquid separation, and the separated aldehyde liquid enters into a furfural primary distillation tower, a furfural dehydration tower and a furfural distillation tower in sequence for distillation, and finally obtains finished furfural; the separated high-temperature gas enters into a heat exchanger through a pipeline for heat exchange, and the hot gas after heat exchange enters into an aldehyde liquid primary distillation tower, an aldehyde liquid drying tower and an aldehyde liquid distillation tower in sequence through a first heat exchange pipeline to participate in the distillation reaction of the aldehyde liquid, and enters into a drying tower through a second heat exchange pipeline to participate in the drying of the furfural raw material, thereby improving the utilization of high-temperature waste heat and reducing energy consumption.

[0030] In the process of waste heat utilization, the amount of gas entering can be adjusted through regulating valves according to the temperature detected by the temperature sensors on each pipeline, thereby achieving efficient utilization of the waste heat of the gas.

Claims

1. A waste heat utilization system for furfural production, comprising a hydrolysis kettle (1) for hydrolyzing furfural, a pure water evaporator (2) for distilling aldehyde vapor after hydrolysis, a furfural primary distillation tower (3), a furfural dehydration tower (4) and a furfural rectification tower (5) are sequentially arranged on the pipeline at the rear end of the hydrolysis kettle, and a first vacuum pump (8) for feeding the aldehyde vapor after hydrolysis to the subsequent process is arranged on the pipeline between the hydrolysis kettle (1) and the pure water evaporator (2); characterized in that: A heat exchanger (6) for exchanging heat for the residual heat of steam after vapor-liquid separation is arranged on the gas outlet pipe of the pure water evaporator (2), and two heat exchange pipes are arranged on the heat exchanger (6), wherein the first heat exchange pipe (9) is respectively connected to the steam inlets of the furfural primary distillation tower (3), the furfural dehydration tower (4) and the furfural distillation tower (5), and the second heat exchange pipe (21) is connected to a drying tower (7) for drying the furfural raw material, the first heat exchange pipe (9) is provided with a second vacuum pump (10), and the second heat exchange pipe (21) is provided with a third vacuum pump (18); the system further comprises a PLC controller for controlling the utilization of residual heat, and the output end of the PLC controller is respectively connected to the input ends of the first vacuum pump (8), the second vacuum pump (10) and the third vacuum pump (18).

2. A waste heat utilization system for furfural production according to claim 1, characterized in that: The first heat exchange pipe (9) is provided with a first heat exchange temperature sensor (11) for detecting the temperature of the gas in the first heat exchange pipe, and the second heat exchange pipe (21) is provided with a second heat exchange temperature sensor (19) for detecting the temperature of the gas in the second heat exchange pipe, and the output ends of the first heat exchange temperature sensor and the second heat exchange temperature sensor are respectively connected to the input end of the PLC controller.

3. A waste heat utilization system for furfural production according to claim 1, characterized in that: The furfural primary distillation tower (3) is provided with a primary distillation tower temperature sensor (13) for detecting the temperature of gas entering the furfural primary distillation tower, the furfural dehydration tower (4) is provided with a dehydration tower temperature sensor (15) for detecting the temperature of gas entering the furfural dehydration tower, and the furfural rectification tower (5) is provided with a rectification tower temperature sensor (17) for detecting the temperature of gas entering the furfural rectification tower. The output ends of the primary distillation tower temperature sensor, the dehydration tower temperature sensor and the rectification tower temperature sensor are respectively connected to the input end of the PLC controller.

4. A waste heat utilization system for furfural production according to claim 1, characterized in that: A first regulating valve (12) for controlling the amount of gas entering is arranged on the pipeline connecting the first heat exchange pipeline (9) and the furfural primary distillation tower (3), a second regulating valve (14) for controlling the amount of gas entering is arranged on the pipeline connecting the first heat exchange pipeline (9) and the furfural dehydration tower (4), and a third regulating valve (16) for controlling the amount of gas entering is arranged on the pipeline connecting the first heat exchange pipeline (9) and the furfural distillation tower (5), and the input ends of the first regulating valve, the second regulating valve and the third regulating valve are respectively connected to the output end of the PLC controller.

5. The waste heat utilization system for furfural production according to claim 1, characterized in that: The second heat exchange pipe (21) is provided with a fourth regulating valve (20) for controlling the amount of gas entering the drying tower, and the input end of the fourth regulating valve is connected to the output end of the PLC controller.

6. A waste heat utilization system for furfural production according to claim 1, characterized in that: The drying tower (7) is provided with a drying box (71) for drying the furfural raw material, a feeding pipe (72) for feeding the drying box is provided above the drying tower, a discharge port (76) for discharging the material is provided at the bottom of the drying tower, a heat conducting sheet (77) for absorbing gas heat is provided on the outer wall of the drying box (71), an exhaust fan (78) for increasing gas flow is provided on the outer wall of the drying tower (7), and an input end of the exhaust fan is connected to an output end of a PLC controller.

7. A waste heat utilization system for furfural production according to claim 6, characterized in that: The drying box (71) is provided with a stirring shaft (74) inside, and a stirring blade (75) is provided on the stirring shaft. The top of the drying tower (7) is provided with a stirring motor (73) for driving the stirring shaft to rotate, and the input end of the stirring motor is connected to the output end of the PLC controller.

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