Recovery and circulation negative carbon system based on membrane separation and s-CO2 circulation

Abstract

The utility model discloses a negative carbon recycling and circulating system based on membrane separation and s-CO2 circulation, which relates to the technical field of waste gas and wastewater treatment and energy recycling and comprises a membrane distillation wastewater device, a membrane separation CO2 trapping device and an s-CO2 power generation device. The membrane separation CO2 trapping device comprises a dust remover, an absorber, a membrane separation assembly and a storage device; the s-CO2 power generation device comprises an evaporator, a turbine, a heat regenerator, a condenser and a power generator; a diverter valve is arranged on the two-way reversible loop, a pipeline where waste gas is located is communicated with the diverter valve, the waste gas enters the two-way reversible loop through the diverter valve, and a membrane distillation device, an s-CO2 power generation device and a membrane separation CO2 trapping device are arranged in the two-way reversible loop. The method is used for solving the problems of low waste heat utilization efficiency of industrial waste gas and waste water and high energy consumption of waste water treatment and CO2 capture in a traditional process, intelligent waste heat distribution and multi-system collaborative optimization are achieved, then efficient energy conversion, water resource recycling and negative carbon emission are achieved, and the purposes of energy conservation, efficiency improvement and green development are achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to industrial waste gas wastewater treatment and energy recovery technical field especially relates to a kind of recycling and circulating carbon-negative system based on membrane separation and s-CO2 circulation. BACKGROUND

[0002] The discharge of industrial waste gas wastewater causes great pressure on the environment and energy consumption, but there are significant energy efficiency and emission problems in traditional treatment processes. To reduce the negative impact of industrial production on the environment and improve resource utilization, waste heat recovery and carbon capture technology is used to achieve "water-energy-carbon" collaborative governance. The principle is to use waste heat to drive energy conversion systems and achieve wastewater purification and CO2 capture through membrane separation technology.

[0003] In the prior art, waste gas wastewater is mainly treated by single process step by step, such as chemical absorption method for capturing CO2 or thermal desalination technology for purifying wastewater. Although it has certain feasibility, it has the following defects: first, chemical absorption method consumes a large amount of chemical agents and regeneration energy consumption, with high carbon emission intensity; second, thermal desalination technology consumes too much energy when treating wastewater, with low efficiency, and cannot effectively utilize waste heat; third, traditional power generation technology does not make full use of waste heat. In addition, the membrane separation and energy recovery system in the prior art lacks collaborative optimization, which makes it difficult to form a closed loop for CO2 capture and energy utilization, restricting the improvement of overall emission reduction and resource recycling efficiency. SUMMARY

[0004] In view of the deficiencies in the prior art, the present utility model provides a recycling and circulating carbon-negative system based on membrane separation and s-CO2 circulation, to solve the problems of low waste heat utilization efficiency, high energy consumption for wastewater treatment and CO2 capture in traditional processes, and to realize intelligent distribution of waste heat and collaborative optimization of multiple systems, thereby achieving efficient energy conversion, water resource recycling and carbon-negative emission, and achieving the goal of energy saving and green development.

[0005] The present utility model achieves the above technical purposes through the following technical means.

[0006] A recycling and circulating carbon-negative system based on membrane separation and s-CO2 circulation, comprising a membrane distillation wastewater device, a membrane separation CO2 capture device and an s-CO2 power generation device. The membrane separation CO2 capture device comprises a dust remover, an absorber, a membrane separation assembly and a storage device. The s-CO2 power generation device comprises an evaporator, a turbine, a regenerator, a condenser and a generator. A shunt valve is provided on the double-path reversible circuit, and the waste gas pipeline is connected to the shunt valve. The waste gas enters the double-path reversible circuit through the shunt valve. The double-path reversible circuit is provided with a membrane distillation device, an s-CO2 power generation device and a membrane separation CO2 capture device.

[0007] In the scheme, the waste gas enters the s-CO2 power generation device or / and the membrane separation CO2 trapping device through the membrane distillation wastewater device.

[0008] In the scheme, the dust remover inlet end is communicated with one end of the flow divider valve output, the dust remover outlet end is communicated with the membrane separation assembly through a pipeline, the membrane separation assembly outlet end is communicated with the absorption tower and the storage device in parallel, and the pipeline on the absorption tower is unidirectionally communicated with the pipeline of the dust remover.

[0009] In the scheme, the flow divider valve is a three-way valve.

[0010] In the scheme, the double-way reversible circuit is communicated with the evaporator, the turbine, the regenerator, the compressor and the condenser are arranged on the pipeline of the evaporator, one end of the turbine is connected with the generator, and the generator is connected with the power grid through a line.

[0011] In the scheme, the waste gas temperature is 510-600 DEG C.

[0012] In the scheme, the condenser is arranged on the pipeline of the wastewater, water pumps are arranged on the inlet side and the outlet side of the condenser, and the wastewater enters the membrane distillation wastewater device through the condenser and the water pumps.

[0013] In the scheme, the double-way reversible circuit can realize bidirectional transportation and parallel transportation.

[0014] In the scheme, the bidirectional transportation is that the waste gas enters the membrane separation CO2 trapping device after passing through the s-CO2 power generation device and the membrane distillation wastewater device.

[0015] Or the waste gas enters the membrane separation CO2 trapping device after passing through the membrane distillation wastewater device and the s-CO2 power generation device.

[0016] The parallel transportation is that part of the waste gas enters the membrane separation CO2 trapping device after passing through the s-CO2 power generation device, and the remaining waste gas enters the membrane separation CO2 trapping device after passing through the membrane distillation wastewater device. Beneficial effects

[0017] The waste gas waste heat intelligent regulation and control distribution of the utility model optimizes the collaborative operation of the power generation, water production and carbon capture system, can maximize the overall efficiency of the system according to different requirements, ensures the efficient and reasonable use of energy, utilizes the membrane distillation technology to combine waste gas waste heat to purify wastewater, reduces the energy consumption of traditional pollutant treatment, improves the wastewater treatment efficiency and water resource utilization rate, adopts the membrane separation technology, continues to input the captured carbon dioxide into the s-CO2 power generation system, realizes negative carbon emission and resource recycling. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 It is the schematic diagram of the recycling and circulating negative carbon system based on membrane separation and s-CO2 cycle.

[0019] Fig. 2 is a schematic diagram of the working principle of a two-way reversible circuit;

[0020] Fig. 3 is a flow chart of three operating modes;

[0021] Fig. 4 is a columnar curve diagram of power generation efficiency and power generation capacity of three modes under 510-600℃ of wastewater and 30kg / s;

[0022] Fig. 5 is a columnar curve diagram of CO2 capture efficiency and capture capacity of three modes under 510-600℃ of wastewater and 30kg / s;

[0023] Fig. 6 is a columnar curve diagram of membrane distillation efficiency and water production of three modes under 510-600℃ of wastewater and 30kg / s.

[0024] Reference signs:

[0025] 1-pollution source (high energy consumption industry); 2-waste gas; 3-wastewater; 4-dividing valve; 5-water pump; 6-evaporator; 7-turbine; 8-heat regenerator; 9-condenser; 10-compressor; 11-generator; 12-power grid; 13-membrane distillation wastewater device; 14-waterworks; 15-dust remover; 16-membrane separation assembly; 17-absorption tower; 18-storage device; 19-two-way reversible circuit. DETAILED DESCRIPTION

[0026] The embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0027] In the description of the present application, it is understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0028] In the utility model, unless another definite provision and limitation, the terms "mount", "link", "connect", "fix" and so on terms should do broad sense understanding, for example, can be fixed connection, also can be detachable connection, or integrally connect;Can be mechanical connection, also can be electrical connection;Can be direct connection, also can through intermediate medium indirectly connect, can be two element internal communication.For ordinary skilled person in the art, the above terms can be understood according to specific circumstances the specific meaning of the utility model.

[0029] A kind of recycling and circulating carbon-negative system based on membrane separation and s-CO2 cycle, including membrane distillation wastewater device 13, membrane separation trapping CO2 device and s-CO2 power generation device;

[0030] The membrane separation trapping CO2 device includes dust collector 15, absorption tower 17, membrane separation component 16 and storage device 18;

[0031] The s-CO2 power generation device includes evaporator 6, turbine 7, regenerator 8, condenser 9 and generator 11;

[0032] Double-path reversible circuit 19 is provided with shunt valve 4, waste gas 2 is connected with shunt valve 4 in pipeline and communicates, waste gas 2 enters double-path reversible circuit 19 by shunt valve 4, and double-path reversible circuit 19 is provided with membrane distillation device 13, s-CO2 power generation device and membrane separation trapping CO2 device.

[0033] The waste gas 2 enters s-CO2 power generation device or / and enters membrane separation trapping CO2 device after passing through membrane distillation wastewater device 13.

[0034] The dust collector 15 inlet end is communicated with the shunt valve 4 output end, the dust collector 15 outlet end is communicated with the membrane separation component 16 by pipeline, the membrane separation component 16 outlet end is connected with the absorption tower 17 and the storage device 18 in parallel, and the pipeline on the absorption tower 17 is unidirectionally communicated with the pipeline of the dust collector 15.

[0035] The shunt valve 4 is a three-way valve.

[0036] The double-path reversible circuit 19 is communicated with evaporator 6, and the turbine 7, regenerator 8, compressor 10 and condenser 9 are arranged on the pipeline of the evaporator 6, one end of the turbine 7 is connected with the generator 11, and the generator 11 is connected with the power grid 12 through a circuit.

[0037] The waste gas temperature is 510-600 DEG C.

[0038] The condenser 9 is arranged on the wastewater pipeline, and water pump 5 is arranged on the inlet side and the outlet side of the condenser 9, and the wastewater enters the membrane distillation wastewater device 13 through the condenser 9 and the water pump 5.

[0039] The double-way reversible circuit 19 can realize bidirectional transportation and parallel transportation.

[0040] Bidirectional transportation: the exhaust gas 2 enters the membrane separation CO2 capture device after passing through the s-CO2 power generation device and the membrane distillation wastewater device 13; or the exhaust gas 2 enters the membrane separation CO2 capture device after passing through the membrane distillation wastewater device 13 and the s-CO2 power generation device.

[0041] Parallel transportation: part of the exhaust gas 2 passes through the s-CO2 power generation device and the membrane separation CO2 capture device; the remaining exhaust gas 2 passes through the membrane distillation wastewater device 13 and the membrane separation CO2 capture device. Embodiment

[0042] A recycling and circulating negative carbon system based on membrane separation and s-CO2 cycle, comprising the following steps:

[0043] Step one: according to the temperature and flow of the exhaust gas and the water production and power generation demand, the shunt valve is used to adjust the series-parallel ratio of the exhaust gas entering the s-CO2 power generation device and the membrane distillation system.

[0044] The operation mode of the intelligent control system includes: mode one (high-temperature power generation priority): the exhaust gas passes through the s-CO2 power generation device, the membrane distillation wastewater device 13 and the membrane separation CO2 capture device in turn, which is suitable for the power demand dominant scene; mode two (water production priority): the exhaust gas enters the membrane distillation wastewater device 13 first, and then passes through the s-CO2 power generation device and the membrane separation CO2 capture device, which is suitable for the water resource shortage scene; mode three (shunt cooperation): the exhaust gas is shunted and processed in parallel, which balances the power generation and water production demand and optimizes the CO2 capture efficiency, which is suitable for the comprehensive benefit maximization scene.

[0045] Step two: the supercritical CO2 working medium is heated by the waste heat of the exhaust gas, and power is generated through the closed Brayton cycle, and the power generation efficiency is improved compared with the traditional steam cycle.

[0046] Step three: the industrial wastewater is preheated by the power generation system and then enters the membrane distillation wastewater device 13, and the waste heat of the exhaust gas passing through the membrane distillation wastewater device 13 is used to increase the temperature difference between the two sides of the membrane, reduce the temperature polarization effect, and improve the water production efficiency.

[0047] Step four: the exhaust gas after waste heat recovery is used is passed through the membrane separation CO2 capture device, the selective permeation membrane separates and captures CO2, and the CO2 is injected into the s-CO2 cycle device as a working medium to form a negative carbon closed loop.

[0048] Combined with the drawings Figs. 1-3As shown, high energy-consuming industry 1 produces exhaust gas 2 and wastewater 3, and the exhaust gas 2 is bidirectional and parallel split in the double-path reversible loop 6 through the intelligent split valve 4. When the electricity demand is high, it is operated in mode one: first through the s-CO2 power generation device including evaporator 6, turbine 7, regenerator 8, condenser 9, compressor 10 and generator 11, then through the membrane distillation wastewater device 13 to heat the wastewater to promote membrane distillation, and finally through the membrane separation CO2 capture device composed of dust remover 15, membrane separation assembly 16, absorption tower 17 and CO2 storage device 18; when the water demand is high, it is operated in mode two; when the comprehensive benefit is maximized, it is operated in mode three. The wastewater 3 is transported to the condenser 9 in the s-CO2 power generation device under the action of the water pump 5 for preheating, and then transported to the membrane distillation system 13 through the water pump 5. The whole system selects the optimal operation mode (mode one to mode three) through the intelligent control subsystem to maximize the energy utilization efficiency, converts the waste gas waste heat into electric energy and enters the power grid 12, purifies the wastewater into fresh water, collects and injects the discharged CO2 into the s-CO2 power generation device to realize negative carbon cycle.

[0049] Figs. 4 to 6 The performance comparison data of three modes under the conditions of exhaust gas temperature 510-600℃ and flow rate 30kg / s are shown.

[0050] Combined with the attached Fig. 4 As shown, the power generation (E) and the operation efficiency both show a monotonous increasing trend with the increase of the inlet exhaust gas temperature (Thin). Among them, Model 1 always leads because of the thermodynamic grade advantage of preferentially using high-temperature exhaust gas (510-600℃) for energy conversion, and always maintains Model 1>Model 2>Model 3. And the power generation gap between Model 1 and Model 2 gradually decreases. The system operation efficiency is Model 1>Model 3>Model 2, reflecting the potential of the split processing mode (Model 1) in the heat-electricity collaborative optimization.

[0051] Combined with the attached Fig. 5 As shown, under the path Model 3, the two gas streams are mixed again before membrane separation, forming a temperature gradient and pressure synergy effect, and the capture performance increases exponentially with the increase of Thin, so Fig. 5 The carbon dioxide capture amount and efficiency PCO2 under the operation route of Model 3 are shown in the figure, which are far higher than Model 1>Model 2, which is the optimal path for carbon dioxide capture.

[0052] Combined with the attached Fig. 6As shown, under the same path mode, changes in temperature (Thin) do not affect changes in yield (Qwater). However, thermodynamic efficiency (J) increases significantly with increasing Thin. Model 2, because its waste gas is not cooled by the power generation system and directly drives the membrane distillation process at high temperature, has an advantage in both water production and efficiency (Model 2 > Model 3 > Model 1). Model 3 balances power generation and water production demands through a diversion strategy. Although its water production is slightly lower than Model 2, it has better system compatibility.

[0053] In summary:

[0054] ① Under different paths, the operating efficiency of each of the three systems increases with increasing temperature;

[0055] ② When electricity demand is the primary factor, Model 1 is the optimal choice, and the end-of-pipe CO2 capture rate can still maintain the baseline level;

[0056] ③ When the water demand is high, Model 2 produces the most water among the three paths; ④ Model 3's CO2 capture efficiency is more than 60% higher than Model 1, and when Thin > 550℃, the water production is close to 85% of Model 2.

[0057] The above embodiments, in conjunction with the accompanying drawings and tables, verify that the present invention achieves cascaded utilization of waste heat through intelligent control. Combined with membrane technology and s-CO2 cycle, it significantly improves energy efficiency and reduces carbon emissions. The system is applicable to industries such as steel, chemical, and power, and has broad application prospects.

Claims

1. A recovery and recycling carbon-negative system based on membrane separation and s-CO2 cycle, characterized in that, The device comprises a membrane distillation wastewater device (13), a membrane separation CO2 trapping device and an s-CO2 power generation device. The membrane separation CO2 trapping device comprises a dust remover (15), an absorption tower (17), a membrane separation assembly (16) and a storage device (18). The s-CO2 power generation device comprises an evaporator (6), a turbine (7), a regenerator (8), a condenser (9) and a generator (11). A shunt valve (4) is arranged on the double-path reversible circuit (19), a pipeline where the exhaust gas (2) is located is connected with the shunt valve (4), the exhaust gas (2) enters the double-path reversible circuit (19) through the shunt valve (4), and the double-path reversible circuit (19) is provided with the membrane distillation wastewater device (13), the s-CO2 power generation device and the membrane separation CO2 trapping device.

2. The recovery and recycling carbon negative system based on membrane separation and s-CO2 cycle according to claim 1, characterized in that, The exhaust gas (2) enters the s-CO2 power generation device or / and enters the membrane separation CO2 trapping device through the membrane distillation wastewater device (13).

3. The recovery and recycling carbon negative system based on membrane separation and s-CO2 cycle of claim 1, wherein, An inlet end of the dust remover (15) is connected with an output end of the shunt valve (4), an outlet end of the dust remover (15) is connected with the membrane separation assembly (16) through a pipeline, the membrane separation assembly (16) is connected with the absorption tower (17) and the storage device (18) in parallel at an outlet end, and a pipeline on the absorption tower (17) is connected with the pipeline where the dust remover (15) is located in a one-way manner.

4. The recovery and recycling carbon negative system based on membrane separation and s-CO2 cycle of claim 1, wherein, The shunt valve (4) is a three-way valve.

5. The membrane separation and s-CO2 cycle based recovery and recycling carbon negative system according to claim 1, wherein, The double-path reversible circuit (19) is connected with the evaporator (6), the pipeline where the evaporator (6) is located is provided with the turbine (7), the regenerator (8), the compressor (10) and the condenser (9), one end of the turbine (7) is connected with the generator (11), and the generator (11) is connected with the power grid (12) through a line.

6. The membrane separation and s-CO2 cycle based recovery and recycling carbon negative system of claim 1, wherein, The temperature of the exhaust gas (2) is 510-600 ℃.

7. The membrane separation and s-CO2 cycle based recovery and recycling carbon negative system of claim 1, wherein, A condenser (9) is arranged on a pipeline where wastewater is located, water pumps (5) are arranged on the inlet side and the outlet side of the condenser (9), and the wastewater enters the membrane distillation wastewater device (13) through the condenser (9) and the water pumps (5).

8. The membrane separation and s-CO2 cycle based recovery and recycling carbon negative system of claim 1, wherein, The double-path reversible circuit (19) can realize bidirectional transportation and parallel transportation.

9. The recovery and recycling carbon-negative system based on membrane separation and s-CO2 cycle of claim 8, wherein, Bidirectional transportation: the exhaust gas (2) enters the membrane separation CO2 trapping device after passing through the s-CO2 power generation device and the membrane distillation wastewater device (13); Or the exhaust gas (2) enters the membrane separation CO2 trapping device after passing through the membrane distillation wastewater device (13) and the s-CO2 power generation device; Parallel transportation: part of the exhaust gas (2) passes through the s-CO2 power generation device and the membrane separation CO2 trapping device, and the remaining exhaust gas (2) passes through the membrane distillation wastewater device (13) and the membrane separation CO2 trapping device.

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