JP2023027729A - Circulating water-type carbon dioxide separation/refinement storage system - Google Patents

Abstract

To provide a system that recovers an exhaust gas from a thermal power plant and carbon dioxide in the atmosphere.SOLUTION: In a stage of "exhaust gas heat exchange-power generation", a high-temperature exhaust gas is pressurized/ heated and heat-exchanged in a first circulation line, and the cooled exhaust gas is injected to a second circulation line. In a stage of "CO2 separation-regeneration", a regeneration tank is installed on a gantry of 30 m and a separation tank is installed on the ground so that the second circulation line circulates between both tanks. The exhaust gas is fed to the second circulation line to be adiabatically expanded and then cooled rapidly. A valve aperture of a valve of a coupling line is adjusted so that a temperature of CO2 is equal to 10°C at which the CO2 can easily dissolve into water, and therefore the CO2 is absorbed into circulation water. When the circulation water flows up into the regeneration tank so that a water pressure drops by a lift-range difference 0.3Mpa, the CO2 saturated in water is blown out and regenerated. In a stage of "methanol generation", H2 is mixed with the regenerated CO2, methanol is generated by catalysis and the methanol is preserved at an ordinary temperature and at an ordinary pressure.SELECTED DRAWING: Figure 2

Description

The present invention is a system for recovering exhaust gases emitted from thermal power plants, ironworks, oil refineries, cement plants, and waste incineration facilities and carbon dioxide contained in the atmosphere.

CCUS (Carbon Dioxide Capture Utilization Storage) collects carbon dioxide from exhaust gases generated from thermal power plants, steel mills, oil refineries, cement plants, and waste incineration facilities, and either fixes it to the bottom of the earth or sea, or synthesizes chemical substances. It is a system that saves data as a trump card for global warming countermeasures, but the cost is a problem.
Exhaust gas, on the other hand, is discharged as gas with 50% or more of its energy remaining underutilized.

Carbon dioxide is adsorbed on the amine, but a large amount of energy is required to regenerate the carbon dioxide. At present, RITE is developing a new absorbent with the goal of reducing energy consumption to 2 GJ/t carbon dioxide, but it is difficult to generate electricity with this method. Technologies for capturing carbon dioxide from the atmosphere are under development. Moreover, there is no technology for separating carbon dioxide in seawater.

Many existing patents have been submitted for regenerating amines by adsorbing carbon dioxide.
On July 10, 2021, we will also use the pressure of the deep sea to store CO2 as a liquid for a long period of time. We are applying for a "system for recovering carbon dioxide from exhaust gas, air, and seawater" that preserves in solid form.

Carbon dioxide is more soluble in water than nitrogen and oxygen at temperatures below 30°C. This property is used to separate and regenerate carbon dioxide. Exhaust gas is over 200°C. Because the water will evaporate. The system has double circulation lines. The first circulation line has a high pressure, absorbs the exhaust gas by the pitot tube effect, pressurizes and heats it. The exhaust gas is cooled in a heat exchanger. The cooled exhaust gas is injected into the next low-pressure circulation line, adiabatically expanded, and quenched to around 10°C. The second circulation line circulates between a separation tank on the ground and a regeneration tank on a 30m-high gantry. Using this lift difference, the separation tank separates nitrogen and oxygen, which are difficult to dissolve in water, and the regeneration tank regenerates carbon dioxide. The regenerated carbon dioxide is mixed with hydrogen and converted to methanol using a catalyst.
The first circulation line can be applied to compressors and air conditioners. Power consumption can be significantly reduced compared to the conventional method.
Air conditioners can collect water and carbon dioxide from the atmosphere at the same time, and the water containing dissolved carbon dioxide is discharged into sewage, where phytoplankton fix carbon dioxide through photosynthesis at sewage treatment plants.

Hot exhaust gases are insoluble in water. need to cool.

To rationally recover carbon dioxide from the atmosphere.

Recovering the thermal energy of the exhaust gas to generate electricity to obtain high-purity carbon dioxide and use it as a raw material for petroleum products.

This system is roughly divided into three stages: "exhaust gas heat exchange/power generation", "CO2 separation/regeneration", and "methanol generation".
In "exhaust gas heat exchange and power generation", high-temperature exhaust gas is pressurized and heated in the first circulation line to perform heat exchange, and the cooled exhaust gas is injected into the second circulation line. Nitrogen and oxygen are heated with a heat exchanger to turn a turbine and generate electricity.
In "CO2 separation and regeneration", a regeneration tank is installed on a gantry with a height of 30m, and a separation tank is installed on the ground, and a second circulation line circulates between them. Exhaust gas is sent from the first circulation line to the second circulation line via the coupling line. Since the first circulation line is set to a higher pressure than the second circulation line, when the exhaust gas is injected, it undergoes adiabatic expansion and is rapidly cooled. The valve opening degree of the coupling line valve is adjusted so that the temperature becomes 10°C, at which CO2 easily dissolves in water. In the separation tank, N2 and O2, which are hardly soluble in water, are separated from the injected exhaust gas. CO2 is readily soluble in water and is absorbed by the circulating water. When the circulating water rises to the regeneration tank, the water pressure drops by 0.3Mpa, so the CO2 saturated in the water blows out and is regenerated.
In "methanol generation", H2 is mixed with regenerated CO2 to generate methanol using a catalyst, and the methanol is stored at normal temperature and pressure.
If this first circulation line is developed, it will also serve as a compressor and an air conditioner. The pitot tube effect allows the air to be drawn into the high pressure circulation line, where the air is compressed. When this compressed air is released from the circulation line, high-pressure air is obtained. Adding an expansion tank to this compressor line makes it a refrigerator and an air conditioner. After cooling around the pressurized tank and sending the cooled air to the expansion tank for adiabatic expansion, the air becomes close to zero.
Water vapor in the air condenses in the expansion tank. Condensed water absorbs carbon dioxide from the air.
When the concentration of carbon dioxide in the condensed water approaches saturation, the condensed water is drained and released into the sewage, where the phytoplankton fix the carbon dioxide through photosynthesis in the sewage treatment plant.
This air conditioner can also heat the room by blowing the hot air around the pressurized tank into the room.

It can separate and regenerate carbon dioxide from exhaust gas and the atmosphere.

Use water as a medium.

Store the regenerated carbon dioxide in methanol or the like.

To recover the heat energy of the exhaust gas and generate electricity.

Figure 1 shows the system of the double circulating water CCUS. It is roughly divided into three stages: "exhaust gas heat exchange and power generation" 1, "CO2 separation and regeneration" 2 "methanol generation" 3. In "exhaust gas heat exchange and power generation" 1, high-temperature exhaust gas 6 is pressurized and heated in the first circulation line 8, heat is exchanged in the heat exchanger heat absorption side 10, and the cooled exhaust gas is sent through the coupling line 17. The N2, O2 14 separated and pressurized in the latter stage, which is injected into the second circulation line 18, is heated on the heating side 11 of the heat exchanger to rotate the turbine 13 and generate electricity. In "CO2 Separation/Regeneration" 2, a regeneration tank 22 is installed on a gantry 4 of 30 m, and a separation tank 21 is installed on the ground, and a second circulation line 18 circulates between them. Since the first circulation line 8 is set to a higher pressure than the second circulation line 18, when the exhaust gas is injected, it undergoes adiabatic expansion and is rapidly cooled. The valve opening degree of the coupling line valve is adjusted so that the temperature becomes 10°C, at which CO2 easily dissolves in water. In the separation tank 21, N2 and O2 14, which are hardly soluble in water, are separated from the injected exhaust gas. CO2 is readily soluble in water and is absorbed by the circulating water. When the circulating water rises to the regeneration tank 22, the water pressure drops by a difference of 0.3 Mpa. Both the first circulation line and the second circulation line form a multiphase flow 7 in the vicinity of the injection of the exhaust gas. In "methanol production" 3, the regenerated CO2 15 is mixed with H2 23 through the dehumidifier 20 to produce methanol in the catalyst 28, and the methanol 36 is stored at normal temperature and normal pressure. Unreacted CO2, H2 33 is returned to compressor 25 as recycle gas 27. Figure 2 shows an air conditioner using a water pump. A circulation line 38 is configured including the pressurized tank 5 and the circulation pump 39 . Room air 41 (0.1 Mpa, 30° C.) is injected into the circulation line (0.2 Mpa) by the pitot tube effect 47 . The air 43 accumulates in the pressurized tank 5, and the pressure and temperature of the air 43 in the pressurized tank 5 increase. This circulation line 38 remains closed until the air temperature reaches 97°C. When the temperature exceeds 97.degree. Further, the valve above the pressurized tank 5 is opened to send the air 43 to the expansion tank 37 . Since the expansion tank 37 is open to the atmosphere, adiabatic expansion 45 occurs and the air is rapidly cooled to 2°C. Water vapor in expansion tank 37 creates condensate 42 . This condensed water 42 is returned to the circulation line 38 . According to a trial calculation, the circulation pump 39 has 400 W, and the cold heat has 6 KW, and the COP value exceeds 10. The reason for this is that the efficiency of a compressor for gas is only about 10%, but the efficiency of a hydraulic pump is nearly 100%, which is a difference of about 10 times. CO 2 in the air also dissolves in the condensed water 42 . If the increased condensed water is discharged from the drain 49 to sewage, phytoplankton first takes in CO2 at the sewage treatment plant, and then it is released into the sea, where plants such as seaweed may collect CO2. This air conditioner can be widely applied to home use, automobile use, and business use such as refrigerators installed in supermarkets, cold storage warehouses, and buildings. If most air conditioners and refrigerators are replaced with hydraulic pumps, it is possible to reduce power consumption and recover several tenths of the total amount of CO2 generated.

Methanol, CCUSS, CO2 fixation

1. Exhaust gas heat exchange/power generation 28. catalyst2. CO2 separation/regeneration 29. condenser3. Methanol production 30 . Gas-liquid separator4. gantry 31 . oil heater5. pressurized tank 32 . oil cooler6. exhaust gas 33 . CO2, H2
7. multiphase flow 34 . crude methanol tank8. First circulation line 35 . vent 9 . First circulation pump 36 . methanol10. heat exchanger endothermic side 37 . expansion tank 11 . Heat exchanger heating side 38 . circulation line 12 . Pump in heat exchanger 39 . circulation pump 13 . turbine 40 . Indoors 14. N2, O2 41. indoor air15. CO2 42. condensed water16. N2, O2 atmospheric release 43. air17. Coupling line 44 . water 18. Second circulation line 45 . adiabatic expansion19. Second circulation pump 46 . mount 20 . Dehumidifier 47 . Pitot tube effect21. Separation tank 48 . Heat dissipation 22. regeneration tank 49 . drain 23 . H2
24. preheater 25 . compressor 26 . Reactor 27 . circulating gas

Claims (10)

High-temperature and low-pressure exhaust gas is injected into a high-pressure pipe circulated by a pump using the pitot tube effect, pressurized and heated, heat exchanged by a heat exchanger, and the cooled exhaust gas is injected into the next circulation pipe. Cooled exhaust gas is injected into a lower pressure circulation pipe, expanded as bubbles in water, cooled by the adiabatic expansion effect, and carbon dioxide in the exhaust gas bubbles dissolves in water at low temperature. A regeneration tank is installed on the gantry and a separation tank is installed on the ground. A circulation line is installed between them to circulate the circulating water. Nitrogen and oxygen that are difficult to dissolve in water are separated, carbon dioxide is easily soluble in water and is absorbed by the circulating water, and when the circulating water rises to the regeneration tank, the water pressure drops by the difference in lift, and carbon dioxide spouts out for regeneration. Low-pressure air is injected into water in a high-pressure circulation line containing a pressurized tank using the pitot tube effect, the air pressure is gradually increased in the pressurized tank, and when the target pressure is exceeded, the air is released from the pressurized tank. Compressor. Low-pressure air is injected into the water in the high-pressure circulation line, which includes the pressurized tank and the expansion tank, by the pitot tube effect. An air conditioner or freezer that decompresses the cooled air in an expansion tank, rapidly expands it, and discharges the cooled air to the object to be cooled. Low-pressure air is injected into the water in the high-pressure circulation line, which includes the pressurized tank and the expansion tank, by the pitot tube effect. As a result of depressurizing and rapidly expanding the air in the expansion tank, the condensed water accumulated in the expansion tank is returned to the high-pressure circulation line by the pitot tube effect. Low-pressure air is injected into the water in the high-pressure circulation line, which includes the pressurized tank and the expansion tank, by the pitot tube effect. As a result of depressurizing and rapidly expanding the air in the expansion tank, the condensed water accumulated in the expansion tank absorbs carbon dioxide in the circulation, and the condensed water is recirculated to the pressurized tank. machine. Low-pressure air is injected into the water in the high-pressure circulation line, which includes the pressurized tank and the expansion tank, by the pitot tube effect. As a result of depressurizing and rapidly expanding the air in the expansion tank, the condensed water accumulated in the expansion tank absorbs carbon dioxide in the circulation, and some of the condensed water is drained and sent to the sewage. machine. A heating system in which low-pressure air is injected into water in a high-pressure circulation line that includes a pressurized tank and an expansion tank using the pitot tube effect, the air in the pressurized tank is heated at high pressure, and the warm air around the pressurized tank is blown into the room. Facility. Phytoplankton performs photosynthesis of water containing carbon dioxide that has flowed into sewage under illumination at a sewage treatment plant, and the carbon dioxide in the sewage is fixed within the phytoplankton.

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