Ethanol heat pump rectification device

Abstract

This utility model belongs to the technical field of ethanol distillation equipment, specifically relating to an ethanol heat pump distillation device, comprising: a distillation column having a liquid inlet, a gas outlet, and a liquid outlet, with a reboiler outlet and a reboiler inlet between the liquid inlet and the liquid outlet; a liquid inlet pipe connecting the liquid inlet and the mother liquor inlet; a first discharge pipe connecting the gas outlet and the finished product outlet, wherein a compressor and a coupled reboiler are sequentially connected along the fluid direction between the gas outlet and the finished product outlet in the first discharge pipe; a second discharge pipe connecting the liquid outlet and the wastewater outlet; and a reboiler pipe connecting the reboiler outlet and the reboiler inlet at both ends, with a coupled reboiler connected between the reboiler outlet and the reboiler inlet, so that the medium at the compressor outlet constitutes the heat source for the coupled reboiler. This utility model uses a compressor to pressurize and heat the low-temperature steam at the top of the column, using it as the heat source for the reboiler in the column bottom, thus realizing the recovery and utilization of latent heat of condensation. Compared with traditional processes, heat pump distillation can reduce steam consumption by 40% to 80%.

Description

Technical Field

[0001] This utility model belongs to the technical field of ethanol distillation equipment, specifically relating to an ethanol heat pump distillation equipment. Background Technology

[0002] Conventional distillation requires heating the column bottoms with an external heat source (such as steam) and simultaneously cooling water to condense the overhead steam, resulting in high energy consumption. The energy consumption is even more significant for the recovery of organic solvents such as ethanol. Ethanol is an important chemical solvent, and its recovery process must balance purity (≥95%) and cost-effectiveness. Traditional processes, due to their high energy consumption, fail to meet environmental and economic requirements. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide an ethanol heat pump distillation device.

[0004] The technical solution adopted by this utility model is as follows: an ethanol heat pump distillation device, comprising:

[0005] A distillation column has a liquid inlet located in the middle of the column, a gas outlet located at the top of the column, and a liquid outlet located in the bottom of the column, and a reboiler outlet and a reboiler inlet are provided between the liquid inlet and the liquid outlet;

[0006] The liquid inlet pipeline connects the liquid inlet and the mother liquor inlet;

[0007] The first discharge pipeline connects the gas outlet and the finished product outlet. A compressor and a coupled reboiler are sequentially connected between the gas outlet and the finished product outlet along the fluid direction.

[0008] The second discharge pipeline connects the liquid outlet and the wastewater discharge outlet;

[0009] The reboiler pipeline is connected to the reboiler outlet and the reboiler inlet at both ends, and a coupling reboiler is connected between the reboiler outlet and the reboiler inlet, so that the medium at the compressor outlet constitutes the heat source of the coupling reboiler.

[0010] An auxiliary reboiler is provided on the reboiler pipeline. The coupled reboiler and the auxiliary reboiler are arranged sequentially along the fluid direction of the reboiler pipeline. The auxiliary reboiler is connected to the steam pipeline.

[0011] The liquid inlet pipeline is connected in sequence with a primary preheater and a secondary preheater along the fluid direction between the mother liquor inlet and the liquid inlet.

[0012] The first discharge pipeline is connected to a primary preheater between the coupled reboiler and the finished product outlet, and the fluid in the liquid inlet pipeline and the material vapor in the first discharge pipeline exchange heat through the primary preheater.

[0013] The second discharge pipeline is connected to a secondary preheater between the liquid outlet and the wastewater discharge outlet, and the fluid in the liquid inlet pipeline and the fluid in the second discharge pipeline exchange heat through the secondary preheater.

[0014] The distillation column has a reflux port at the top of the column. The first discharge pipeline is provided with a condensate tank between the primary preheater and the finished product outlet, and a reflux pipeline is connected between the condensate tank and the finished product outlet. The reflux pipeline is connected to the reflux port.

[0015] The condensate tank is provided with a vent at the top, and the vent is connected to the vent outlet through a vent pipeline.

[0016] The venting pipeline has a primary condenser and a secondary condenser sequentially arranged along the fluid direction between the venting port and the venting outlet. The outlet ends of the primary condenser and the secondary condenser are connected to the venting condenser tank through pipelines.

[0017] A heavy component cooler is connected between the secondary preheater and the wastewater discharge outlet.

[0018] The beneficial effects of this invention are as follows: This invention uses a compressor to pressurize and heat the low-temperature steam at the top of the column, using it as a heat source for the reboiler in the bottom of the column, thus realizing the recovery and utilization of latent heat of condensation. Compared with traditional processes, heat pump distillation can reduce steam consumption by 40% to 80%. The system of this invention does not require a column top condenser, boiler heating system, or circulating pumps and other utilities. The entire logistics system achieves fully enclosed operation, significantly reducing production costs. Furthermore, by reducing the demand for external energy and producing water as a byproduct of the ethanol feedstock, it achieves zero emissions, thus balancing economic efficiency, energy conservation, and environmental protection. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of this utility model.

[0020] Figure 1 This is a schematic diagram of the structure of one embodiment of the present utility model;

[0021] Figure 2 This is a schematic diagram of the structure of the distillation column in one embodiment of the present invention;

[0022] In the diagram, 1. Primary preheater; 2. Condensate tank; 3. Secondary preheater; 4. Heavy component cooler; 5. Primary condenser; 6. Secondary condenser; 7. Compressor; 8. Distillation column; 801. Liquid inlet; 802. Gas outlet; 803. Liquid outlet; 804. Reflux outlet; 805. Reboiler outlet; 806. Reboiler inlet; 9. Coupled reboiler; 10. Auxiliary reboiler; 11. Vent condenser.

[0023] A. Mother liquor inlet; B. Finished product outlet; C. Wastewater discharge outlet; D. Vent outlet; E. Steam inlet; F. Steam outlet. Detailed Implementation

[0024] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0025] This utility model provides an ethanol heat pump distillation device, such as... Figure 1 As shown, it includes a distillation column 8 and an inlet pipe, a first outlet pipe, a second outlet pipe, and a reboiler pipe connected to the distillation column 8.

[0026] like Figure 2 As shown, the distillation column 8 has a liquid inlet 801 located in the middle of the column, a gas outlet 802 located at the top of the column, and a liquid outlet 803 located in the bottom of the column. A reboiler outlet 805 and a reboiler inlet 806 are provided between the liquid inlet 801 and the liquid outlet 803.

[0027] The inlet pipeline connects the inlet 801 and the mother liquor inlet A, and is used to deliver the mother liquor to be distilled to the distillation column 8. A primary preheater 1 and a secondary preheater 3 are installed in sequence on the pipeline to preheat the mother liquor entering the inlet pipeline through the mother liquor inlet A to the set feed temperature.

[0028] The first discharge pipeline connects the gas outlet 802 and the finished product outlet B, and is used to discharge the material vapor from the top of the distillation column 8. Along the fluid direction between the gas outlet 802 and the finished product outlet B, the pipeline is connected in sequence a compressor 7, a coupled reboiler 9, and a primary preheater 1. The compressor 7 pressurizes and heats the material vapor discharged from the top of the column. The coupled reboiler 9 is used to provide heat to the distillation system using the heated material vapor, realizing the recovery and utilization of latent heat of condensation. The primary preheater 1 is used to preheat the mother liquor using the residual temperature of the material, fully recovering and utilizing the latent heat of condensation of the material.

[0029] The second discharge pipeline connects the liquid outlet 803 and the wastewater outlet C, and is used to discharge the residual liquid in the bottom of the distillation column 8 after distillation. A secondary preheater 3 is connected to the liquid outlet 803 and the wastewater outlet C on the pipeline. The secondary preheater 3 is used to preheat the mother liquor with the heat of the discharged water and recover the heat of the discharged residual liquid.

[0030] The reboiling pipeline is connected at both ends to the reboiling outlet 805 and the reboiling inlet 806. A coupling reboiler 9 and an auxiliary reboiler 10 are connected between the reboiling outlet 805 and the reboiling inlet 806, arranged sequentially along the fluid direction of the reboiling pipeline. The medium at the outlet of the compressor 7 constitutes the heat source of the coupling reboiler 9. The auxiliary reboiler 10 is connected to the steam inlet E and the steam outlet F through a steam pipeline. External steam provides a heat source for the auxiliary reboiler 10, so that the distillation feedstock is heated to the set feed temperature.

[0031] The overhead vapor contains a significant amount of ethanol. The device controlling the distillation column 8 to operate at a slightly positive pressure ensures that the overhead vapor temperature is approximately 79°C. After being pressurized by compressor 7, the temperature of the material vapor can be raised to approximately 115°C, which is then supplied to the reboiler line for heat exchange, thus providing a heat source for the system. The bottom liquid is heated to approximately 103°C. The primary preheater 1 and the secondary preheater 3 utilize the residual heat of the overhead vapor after passing through the coupled reboiler 9 and the 103°C temperature of the bottom liquid to preheat the mother liquor in two stages, raising it to approximately 84°C. The mother liquor then enters the distillation column. The reboiler line heats the material in the distillation column with the material vapor, which has been pressurized and heated by the compressor, and the externally supplied steam heat source, until the set temperature of 103°C is reached, thus enabling distillation.

[0032] Furthermore, the distillation column 8 has a reflux port 804 located at the top of the column. A condensate tank 2 is installed between the first-stage preheater 1 and the product outlet B in the first discharge pipeline, and a reflux pipeline is connected between the condensate tank 2 and the product outlet B. The reflux pipeline is connected to the reflux port 804. The condensate from the condensate tank 2 is pumped back to the top of the distillation column 8 for total reflux. After a period of total reflux, the reflux is collected according to the designed reflux ratio, and qualified ethanol product of the set concentration is collected.

[0033] The top of the condensate tank 2 is provided with a vent port, which is connected to the vent outlet D through a vent pipeline. A primary condenser 5 and a secondary condenser 6 are sequentially arranged in the vent pipeline along the fluid direction between the vent port and the vent outlet D. The outlet ends of the primary condenser 5 and the secondary condenser 6 are connected to the vent condensate tank 11 through pipelines to achieve zero discharge.

[0034] A heavy component cooler 4 is connected between the secondary preheater 3 and the wastewater discharge outlet C.

[0035] The primary preheater 1, secondary preheater 3, primary condenser 5, secondary condenser 6, and heavy component cooler 4 of this utility model can be one of a tubular heat exchanger, a spiral plate heat exchanger, a wound tube heat exchanger, or a plate heat exchanger.

[0036] The compressor 7 of this invention can be a piston compressor, screw compressor, centrifugal compressor, or linear compressor.

[0037] The following are some embodiments of ethanol distillation using the ethanol heat pump distillation device of this invention.

[0038] Example 1

[0039] The raw material, containing 52% ethanol, 43% water, and 5% salt, is heated to 84°C in a primary preheater 1 after being compressed and then condensed. The raw material and the residual liquid discharged from the bottom of the column are heated to 84°C in a secondary preheater 3. The heated raw material then enters the distillation column 8. The liquid flows into the coupled reboiler 9 and the auxiliary reboiler 10. The gas enters the compressor 7 from the top of the column and then enters the coupled reboiler 9 to provide heat for the coupled reboiler 9. After heat exchange, the condensate flows into the primary preheater 1 and exchanges heat with the raw material before entering the condensate tank 2. The condensate tank 2 is pumped back to the top of the distillation column 8 for total reflux. After a period of total reflux, the reflux is collected according to the designed reflux ratio, and qualified 84% ethanol product is collected.

[0040] The cost comparison with conventional distillation methods is as follows:

[0041]

[0042] By calculating the energy consumption of this invention and conventional distillation, it is found that the invention consumes 0.48 tons of steam per hour, 80 tons of circulating water per hour, a pump power of 90 kW, and a compressor power of 314 kW. Conventional distillation consumes 3.49 tons of steam per hour, 250 tons of circulating water per hour, and a pump power of 15 kW. Using a cost of 200 yuan per ton of steam, 0.2 yuan per ton of circulating water, and 0.75 yuan per kilowatt of electricity, the annual operating cost of this invention is calculated to be 2.99 million yuan, while the annual operating cost of conventional distillation is 5.47 million yuan. This invention can save 2.48 million yuan in operating costs per year. The comparison shows that conventional distillation has a higher operating cost when purifying ethanol to the same concentration, while adding a heat pump system reduces operating costs and makes it easier to meet purification requirements.

[0043] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

Claims

1. An ethanol heat pump distillation apparatus, characterized in that, include: The distillation column (8) has a liquid inlet (801) located in the middle of the column, a gas outlet (802) located at the top of the column, and a liquid outlet (803) located at the bottom of the column. A reboiler outlet (805) and a reboiler inlet (806) are provided between the liquid inlet (801) and the liquid outlet (803). The liquid inlet pipeline connects the liquid inlet (801) and the mother liquor inlet (A). The first discharge pipeline connects the gas outlet (802) and the finished product outlet (B). The first discharge pipeline is connected in sequence with a compressor (7) and a coupling reboiler (9) along the fluid direction between the gas outlet (802) and the finished product outlet (B). The second discharge pipeline connects the liquid outlet (803) and the wastewater discharge outlet (C); The reboiling pipeline is connected at both ends to the reboiling outlet (805) and the reboiling inlet (806), and a coupling reboiler (9) is connected between the reboiling outlet (805) and the reboiling inlet (806), so that the medium at the outlet of the compressor (7) constitutes the heat source of the coupling reboiler (9).

2. The ethanol heat pump distillation apparatus according to claim 1, characterized in that: An auxiliary reboiler (10) is provided on the reboiler pipeline. The coupled reboiler (9) and the auxiliary reboiler (10) are arranged sequentially along the fluid direction of the reboiler pipeline. The auxiliary reboiler (10) is connected to the steam pipeline.

3. The ethanol heat pump distillation apparatus according to claim 1, characterized in that: The liquid inlet pipeline is connected in sequence with a primary preheater (1) and a secondary preheater (3) along the fluid direction between the mother liquor inlet (A) and the liquid inlet (801). The first discharge pipeline is connected to a primary preheater (1) between the coupled reboiler (9) and the finished product outlet (B). The fluid in the liquid inlet pipeline and the material steam in the first discharge pipeline exchange heat through the primary preheater (1). The second discharge pipeline is connected to a secondary preheater (3) between the liquid outlet (803) and the wastewater outlet (C), and the fluid in the liquid inlet pipeline and the fluid in the second discharge pipeline exchange heat through the secondary preheater (3).

4. The ethanol heat pump distillation apparatus according to claim 3, characterized in that: The distillation column (8) has a reflux port (804) at the top of the column. The first discharge pipeline is provided with a condensate tank (2) between the primary preheater (1) and the finished product outlet (B), and a reflux pipeline is connected between the condensate tank (2) and the finished product outlet (B). The reflux pipeline is connected to the reflux port (804).

5. The ethanol heat pump distillation apparatus according to claim 4, characterized in that: The condensate tank (2) is provided with a vent at the top, and the vent is connected to the vent outlet (D) through a vent pipeline.

6. The ethanol heat pump distillation apparatus according to claim 5, characterized in that: The venting pipeline is provided with a primary condenser (5) and a secondary condenser (6) in sequence along the fluid direction between the venting port and the venting outlet (D). The outlet ends of the primary condenser (5) and the secondary condenser (6) are connected to the venting condenser tank (11) through pipelines.

7. The ethanol heat pump distillation apparatus according to claim 3, characterized in that: A heavy component cooler (4) is connected between the secondary preheater (3) and the wastewater outlet (C).

Images