A device and method for recovering CO2 from combustion flue gas

Abstract

The present invention discloses a device and method for resource recovery of CO2 in combustion flue gas, relating to the technical field of CO2 recovery in combustion flue gas, including an atomizing cyclone device, a condensation crystallization device, a concentration absorption tower, a deep absorption tower and an absorption liquid circulation device; the present invention adopts an atomizing cyclone device to realize resource recovery of CO2 from flue gas that has been subjected to dust removal and desulfurization treatment, and the flue gas entering is first fully contacted with the atomized absorption liquid sprayed from a multi-point spray array to form a flue gas absorption liquid mixture, the absorption liquid circulation device provides CO2 absorption liquid to the atomizing cyclone device, the concentration absorption tower and the deep absorption tower respectively, and the absorption liquid demand of the entire device can be met by only adding absorption liquid through the absorption liquid box at the bottom of the deep absorption tower, thereby realizing resource recovery of CO2 from the flue gas of enterprises with small flue gas volume and scattered distribution, and can also be used in large-scale CO2 resource recovery scenarios such as thermal power plants, the process and equipment are stable and reliable, the operation is flexible, and the CO2 absorption conversion rate is high.

Description

Technical Field

[0001] The present invention relates to the technical field of CO2 recovery from combustion flue gas, and in particular to a device and method for resource recovery of CO2 from combustion flue gas. Background Art

[0002] At present, CO2 capture in flue gas is commonly achieved through nitrogen injection, temperature swing absorption, pressure swing absorption, and adsorption membrane separation. These methods are generally targeted at coal-fired power plants and other entities that produce large amounts of CO2 and require a complex post-processing system. They are also difficult to apply to other enterprises that use CO2 or (NH4)2CO3 as raw materials, such as glass factories and ceramic factories, which have smaller and more scattered flue gas volumes.

[0003] Therefore, developing a device and supporting method for resource recovery of CO2 from flue gas suitable for glass factories, ceramic factories and other enterprises with small flue gas volume and loose distribution is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] In order to solve the above-mentioned technical problem of CO2 resource recovery in flue gas, the present invention provides a device and method for CO2 resource recovery in combustion flue gas. The following technical solutions are adopted:

[0005] A CO2 resource recovery device in combustion flue gas, comprising an atomizing cyclone device, a condensation crystallization device, a concentration absorption tower, a deep absorption tower and an absorption liquid circulation device;

[0006] The atomizing cyclone device includes an air inlet pipe, a multi-point spray array and a spherical cyclone separator. The flue gas pipe is connected to the air inlet pipe. The multi-point spray array is installed on the inner wall of the air inlet pipe and is located at one end connected to the flue gas pipe. The spherical cyclone separator is provided with a flue gas inlet, a gas phase outlet after gas-liquid phase separation, and a liquid phase outlet. The flue gas inlet is connected to the other end of the air inlet pipe. The spherical cyclone separator guides the flue gas absorption liquid mixture into a cyclone state and separates the gas and liquid phases in the cyclone state. The condensation crystallization device is installed at the bottom liquid phase outlet of the spherical cyclone separator. The inlet of the condensation crystallization device is connected to the liquid phase outlet. After the liquid phase is condensed and crystallized, high-speed solid-liquid separation is performed to obtain a solid phase product and a liquid absorption liquid. The liquid absorption liquid is then connected to the inlet of the multi-point spray array after temperature adjustment and atomization.

[0007] The concentration absorption tower is equipped with a secondary flue gas absorption inlet and a secondary flue gas outlet. The gas phase outlet of the spherical cyclone separator is connected to the secondary flue gas absorption inlet. The flue gas after multi-stage spray absorption is discharged through the secondary flue gas outlet.

[0008] The deep absorption tower is equipped with a residual flue gas absorption inlet and a tail gas exhaust outlet. The residual flue gas absorption inlet is connected to the secondary flue gas outlet of the concentrated absorption tower. The tail gas after being absorbed by the multi-stage filler is discharged from the tail gas exhaust outlet.

[0009] The absorption liquid circulation device provides CO2 absorption liquid to the atomizing cyclone device, the concentration absorption tower and the deep absorption tower respectively.

[0010] By adopting the above technical solution, an atomizing cyclone device is used to realize the resource recovery of CO2 from the flue gas that has been treated with dust removal and desulfurization. The flue gas first contacts with the atomized absorption liquid sprayed from the multi-point spray array to form a flue gas absorption liquid mixture. After entering the spherical cyclone separator, the spherical cyclone separator makes the flue gas absorption liquid mixture into a cyclone state under the guidance of some cyclone guide structures, and separates the gas and liquid phases in the cyclone state. The gas-liquid phase separation can be achieved by using a condenser, etc. After the gas-liquid phase separation, the liquid phase is condensed by a condensation crystallization device to obtain a solid phase product and a liquid absorption liquid. The solid phase product is sodium bicarbonate. The liquid absorption liquid is again temperature-controlled and atomized to provide absorption liquid for the multi-point spray array.

[0011] After the gas-liquid separation in the spherical cyclone separator, there will still be some CO2 remaining in the gas phase. It will first enter the concentration absorption tower for secondary spray absorption, and finally enter the deep absorption tower for multi-stage absorption. The CO2 remaining in the tail gas is very small and can be directly discharged through the pipeline.

[0012] The absorption liquid circulation device can provide CO2 absorption liquid for the atomizing cyclone device, the concentration absorption tower and the deep absorption tower respectively. The absorption liquid demand of the entire device can be met by simply adding absorption liquid through the absorption liquid tank at the bottom of the deep absorption tower, thereby realizing the resource recovery of CO2 in the flue gas of enterprises with small flue gas volume and loose distribution. It can also be used in large-scale CO2 resource recovery scenarios such as thermal power plants. The process and equipment are stable and reliable, the operation is flexible, and the CO2 absorption conversion rate is high.

[0013] Optionally, the spherical cyclone separator includes a spherical shell, multiple cyclone guide plates and a condensing demister, wherein a flue gas inlet is provided on one side of the spherical shell, a gas phase outlet is provided on the other side, and a liquid phase outlet is provided at the bottom, the multiple cyclone guide plates are respectively mounted on the inner wall of the spherical shell, and the intervals between the multiple cyclone guide plates are used to guide the incoming flue gas absorption liquid mixture into a cyclone state, the condensing demister is installed at the gas phase outlet and protrudes into the interior of the spherical shell, and the gas phase outlet of the spherical shell is connected to the secondary flue gas absorption inlet of the concentration absorption tower.

[0014] By adopting the above technical solution, swirl blades are set at the flue gas inlet of the spherical shell, so that the flue gas is already in a swirl state when entering the spherical separator. The spherical shell is equipped with multiple swirl guide plates, and a swirl channel is formed between adjacent swirl guide plates. The rotation radius of the flue gas absorption liquid mixture gradually increases in the early stage of the swirl, and gradually decreases after passing through the middle of the spherical shell. The swirl diameter gradually changes, and the pressure along the spherical surface is greater than that near the center line. This realizes the diversion of inlet and outlet gases in a small space, reduces the proportion of direct short-circuit gas outflow, and under the action of the internal swirl gas and the mainstream return gas, improves the mixing uniformity of the absorption liquid and flue gas, and improves the CO2 recovery rate. The condensation demister protrudes into the interior of the spherical shell, and the protrusion is generally set to reach one-quarter to one-third of the diameter of the spherical shell. The condensation array plates of the condensation demister adopt V-shaped plates. The V-shaped plates of different layers are staggered, which can efficiently condense the droplets, causing the droplets to aggregate and grow and finally fall.

[0015] Optionally, the condensation crystallization device includes a condensation crystallization tank, a chiller, a cold water coil and a high-speed centrifugal separator, the top opening of the condensation crystallization tank is connected to the liquid phase outlet at the bottom of the spherical shell, the cold water coil is installed around the inner wall of the condensation crystallization tank, the circulating water inlet and outlet of the chiller are connected to both ends of the cold water coil, a condensation channel is formed in the cold water coil, and the inlet of the high-speed centrifugal separator is connected to the bottom opening of the condensation crystallization tank through a pipe, which is used to perform solid-liquid phase separation on the solid-liquid mixture falling from the condensation channel.

[0016] By adopting the above technical solution, the condensation crystallization device provides cold water of 5℃-10℃ for the cold water coil based on the chiller, so that the temperature of the absorption liquid in the condensation crystallization tank is 10-15 degrees, and the liquid phase is condensed to obtain a solid product of sodium bicarbonate. During the condensation process, some absorption liquid remains in liquid state. The solid and liquid enter the high-speed centrifuge together to achieve solid-liquid separation. The solid phase product is solid sodium bicarbonate, and the liquid absorption liquid flows into the subsequent absorption liquid circulation device for reuse, thereby efficiently realizing CO2 resource recovery, and the absorption liquid can be recycled repeatedly.

[0017] Optionally, the concentration absorption tower includes a first tower body, a cyclone plate demister and a multi-stage spray device, wherein the multi-stage spray device is installed in the middle of the first tower body, the cyclone plate demister is installed in the first tower body and is located above the multi-stage spray device, and a secondary flue gas absorption inlet is provided on one side of the bottom of the first tower body and a secondary flue gas outlet is provided on the top.

[0018] By adopting the above technical solution, the concentration absorption tower adopts a multi-stage spray device to achieve secondary absorption of CO2, and adopts an atmospheric liquid ratio multi-stage spray with a gas-liquid ratio of 1-20m 3 Liquid / 1000m 3 Gas, no filler, the CO2 content in the flue gas after secondary absorption is very low, and it enters the deep absorption tower after being defogged by the cyclone plate demister.

[0019] Optionally, the deep absorption tower includes a second tower body, a multi-stage packing absorption device and a demister, a residual flue gas absorption inlet is provided on one side of the bottom of the second tower body, and an exhaust gas outlet is provided on the top, the multi-stage packing absorption device is installed in the middle of the second tower body, the demister is installed in the second tower body and is located above the multi-stage packing absorption device, and the residual flue gas absorption inlet is connected to the secondary flue gas outlet of the first tower body through a pipe.

[0020] By adopting the above technical solution, the deep absorption tower adopts a multi-stage filler absorption device with no limit on filler type and a gas-liquid ratio of 1-20m 3 Liquid / 1000m 3 Gas, can effectively absorb CO2 residue.

[0021] Optionally, the absorption liquid circulation device includes a second tower body absorption liquid tank, a first tower body absorption liquid tank, a spray absorption liquid adjustment device and an atomizer, the liquid outlet of the second tower body absorption liquid tank is connected to the liquid inlet of the multi-stage filler absorption device of the deep absorption tower through a water pump and a pipeline, providing absorption liquid for the multi-stage filler absorption device, and is connected to the liquid inlet of the first tower body absorption liquid tank through a water pump and a pipeline, replenishing absorption liquid for the first tower body absorption liquid tank, and the liquid outlet of the first tower body absorption liquid tank is connected to the liquid inlet of the multi-stage spray device through a water pump and a pipeline, providing absorption liquid for the multi-stage spray device;

[0022] The spray absorption liquid adjustment device includes a stirring tank, an agitator and a heater. The inlet of the stirring tank is connected to the second tower absorption liquid tank and the liquid phase outlet of the high-speed centrifuge through a pipeline. The agitator and the heater are respectively installed in the stirring tank. The inlet of the atomizer is connected to the outlet at the bottom of the stirring tank through a pipeline and a water pump. The outlet of the atomizer is connected to the inlet of the multi-point spray array through a pipeline.

[0023] Optionally, the second tower absorption liquid tank and the first tower absorption liquid tank are respectively provided with electronic liquid level gauges, and absorption liquid is added to the second tower absorption liquid tank and the first tower absorption liquid tank according to the liquid levels monitored by the electronic liquid level gauges.

[0024] Optionally, the absorption liquid added to the absorption liquid box of the second tower body is a mixture of sodium carbonate and sodium hydroxide.

[0025] By adopting the above technical solution, the entire absorption liquid circulation device only needs to add absorption liquid at the inlet of the absorption liquid tank of the second tower body. The absorption liquid can be a mixture of sodium carbonate and sodium hydroxide. The replenishment process can use an automated adding device. When the liquid level monitored by the electronic liquid level meter is lower than the set liquid level, sodium carbonate, sodium hydroxide and water are added to ensure the final CO2 absorption efficiency.

[0026] Optionally, multiple groups of nozzles of the multi-point spray array are directed toward the flue gas duct.

[0027] By adopting the above technical solution, the structure of the multi-point spray array can be a multi-layer nozzle array with multiple groups of nozzles installed. The multiple groups of nozzles facing the flue gas duct can make the spray direction opposite to the flue gas flow direction, increase the relative velocity of gas and liquid, and increase the CO2 absorption rate.

[0028] A method for recovering CO2 from combustion flue gas by recycling it, using a device for recovering CO2 from combustion flue gas, comprises the following steps:

[0029] Step 1: The flue gas to be recovered from CO2 is introduced into the air intake pipe from the flue gas pipe, and the multi-point spray array sprays the atomized absorption liquid to form a gas-liquid mixture that enters the spherical shell;

[0030] Step 2: The swirl flow is guided by the multiple swirl guide plates. The initial swirl radius gradually increases, and after passing through the middle of the spherical shell, the swirl radius gradually decreases. The condenser demister absorbs the droplets, and the droplets gradually grow larger and fall. The gaseous flue gas after gas-liquid separation enters the concentration absorption tower through the gas phase outlet and the secondary flue gas absorption inlet in sequence and moves upward.

[0031] In step 3, the ascending flue gas contacts the absorption liquid sprayed by the multi-stage spray device, absorbs the residual CO2 again, passes through the cyclone plate demister, enters the first tower body through the secondary flue gas outlet and the residual flue gas absorption inlet, and ascends. After passing through the multi-stage packing absorption device, it is finally discharged through the tail gas outlet and pipeline under the absorption effect;

[0032] Step 4: After gas-liquid separation, the liquid phase falls into the condensation crystallization tank. Under the cooling effect of the cold water coil, a solid-liquid mixture is formed and enters the high-speed centrifuge. The high-speed centrifuge separates the solid-liquid mixture falling from the condensation channel into solid-liquid phases. The solid phase is the CO2 resource recovery product, and the liquid phase enters the spray absorption liquid adjustment device, which is heated and stirred to provide the absorption liquid for the atomizer;

[0033] In step 5, in step 3, the CO2 absorbed in the absorption liquid in the concentration absorption tower and the deep absorption tower finally passes through the absorption liquid circulation device and enters the atomizing cyclone device again through the multi-point spray array.

[0034] In summary, the present invention includes at least one of the following beneficial technical effects:

[0035] The present invention can provide a device and method for resource recovery of CO2 from combustion flue gas, which adopts an atomizing cyclone device to realize resource recovery of CO2 from flue gas that has been subjected to dust removal and desulfurization treatment. When the flue gas enters, it first fully contacts with the atomized absorption liquid sprayed from a multi-point spray array to form a flue gas absorption liquid mixture. The spherical cyclone separator, under the guidance of some cyclone guide structures, makes the flue gas absorption liquid mixture into a cyclonic state, and separates the gas and liquid phases in the cyclonic state. After the gas and liquid phases are separated, the liquid phase is condensed by a condensation crystallization device to obtain a solid phase product and a liquid absorption liquid. The solid phase product is sodium bicarbonate. The liquid absorption liquid is again temperature-controlled and atomized to provide absorption liquid for the multi-point spray array.

[0036] The flue gas after gas-liquid separation in the spherical cyclone separator first enters the concentration absorption tower for secondary spray absorption, and finally enters the deep absorption tower for multi-stage packing to absorb the CO2 in the tail gas;

[0037] The absorption liquid circulation device provides CO2 absorption liquid for the atomizing cyclone device, the concentration absorption tower and the deep absorption tower respectively. The absorption liquid demand of the entire device can be met by simply adding absorption liquid through the absorption liquid tank at the bottom of the deep absorption tower, thereby realizing the resource recovery of CO2 in the flue gas of enterprises with small flue gas volume and loose distribution. It can also be used in large-scale CO2 resource recovery scenarios such as thermal power plants. The process and equipment are stable and reliable, the operation is flexible, and the CO2 absorption conversion rate is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the connection principle of components of a CO2 resource recovery device in combustion flue gas according to the present invention;

[0039] Figure 2 It is a schematic diagram of the connection of components of an atomizing cyclone device and a condensation crystallization device of a CO2 resource recovery device in combustion flue gas of the present invention.

[0040] Figure 3 It is a flow chart of a method for resource recovery of CO2 from combustion flue gas according to the present invention.

[0041] Explanation of the accompanying symbols: 11. Air inlet pipe; 12. Multi-point spray array; 131. Spherical shell; 132. Cyclone guide plate; 133. Condensation demister; 141. Condensation crystallization tank; 142. Chiller; 143. Cold water coil; 144. High-speed centrifuge; 2. Concentration absorption tower; 21. First tower body; 22. Cyclone plate demister; 23. Multi-stage spray device; 3. Deep absorption tower; 31. Second tower body; 32. Multi-stage packing absorption device; 33. demister; 41. Second tower body absorption liquid tank; 42. First tower body absorption liquid tank; 431. Mixing tank; 432. Agitator; 44. Atomizer; 100. Flue gas duct. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below with reference to the accompanying drawings.

[0043] The embodiment of the present invention discloses a device and method for resource recovery of CO2 from combustion flue gas.

[0044] Reference Figure 1 - Figure 3 , Example 1, a CO2 resource recovery device in combustion flue gas, including an atomizing cyclone device, a condensation crystallization device, a concentration absorption tower 2, a deep absorption tower 3 and an absorption liquid circulation device;

[0045] The atomizing cyclone device includes an air inlet pipe 11, a multi-point spray array 12 and a spherical cyclone separator. The flue gas pipe 100 is connected to the air inlet pipe 11. The multi-point spray array 12 is installed on the inner wall of the air inlet pipe 11 and is located at one end connected to the flue gas pipe 100. The spherical cyclone separator is provided with a flue gas inlet, a gas phase outlet after gas-liquid phase separation, and a liquid phase outlet. The flue gas inlet is connected to the other end of the air inlet pipe 11. The spherical cyclone separator guides the flue gas absorption liquid mixture into a cyclone state and separates the gas and liquid phases in the cyclone state. The condensation crystallization device is installed at the bottom liquid phase outlet of the spherical cyclone separator. The inlet of the condensation crystallization device is connected to the liquid phase outlet. After the liquid phase is condensed and crystallized, high-speed solid-liquid separation is performed to obtain a solid phase product and a liquid absorption liquid. The liquid absorption liquid is then connected to the inlet of the multi-point spray array 12 after temperature adjustment and atomization.

[0046] The concentration absorption tower 2 is provided with a secondary flue gas absorption inlet and a secondary flue gas outlet. The gas phase outlet of the spherical cyclone separator is connected to the secondary flue gas absorption inlet. The flue gas after multi-stage spray absorption is discharged through the secondary flue gas outlet.

[0047] The deep absorption tower 3 is provided with a residual flue gas absorption inlet and an exhaust gas outlet. The residual flue gas absorption inlet is connected to the secondary flue gas outlet of the concentrated absorption tower 2. The exhaust gas after being absorbed by the multi-stage filler is discharged from the exhaust gas outlet.

[0048] The absorption liquid circulation device provides CO2 absorption liquid to the atomizing cyclone device, the concentration absorption tower 2 and the deep absorption tower 3 respectively.

[0049] An atomizing cyclone device is used to realize the resource recovery of CO2 from the flue gas that has been treated with dust removal and desulfurization. When the flue gas enters, it first contacts the atomized absorption liquid sprayed from the multi-point spray array 12 to form a flue gas absorption liquid mixture. After entering the spherical cyclone separator, the spherical cyclone separator causes the flue gas absorption liquid mixture to form a cyclone state under the guidance of some cyclone guide structures, and the gas-liquid phase is separated in the cyclone state. The gas-liquid phase separation can be achieved by using a condenser, etc. After the gas-liquid phase separation, the liquid phase is condensed by a condensation crystallization device to obtain a solid phase product and a liquid absorption liquid. The solid phase product is sodium bicarbonate. The liquid absorption liquid is again temperature-controlled and atomized to provide absorption liquid for the multi-point spray array 12.

[0050] After the gas-liquid separation in the spherical cyclone separator, there will still be some CO2 remaining in the gas phase. It will first enter the concentration absorption tower 2 for secondary spray absorption, and finally enter the deep absorption tower 3. After multi-stage absorption by packing, there will be very little CO2 remaining in the tail gas, which can be directly discharged through the pipeline.

[0051] The absorption liquid circulation device can provide CO2 absorption liquid for the atomizing cyclone device, the concentration absorption tower 2 and the deep absorption tower 3 respectively. The absorption liquid demand of the entire device can be met by simply adding absorption liquid through the absorption liquid tank at the bottom of the deep absorption tower 3, thereby realizing the resource recovery of CO2 in the flue gas of enterprises with small flue gas volume and loose distribution. It can also be used in large-scale CO2 resource recovery scenarios such as thermal power plants. The process and equipment are stable, reliable, flexible to operate, and have a high CO2 absorption conversion rate.

[0052] Example 2, the spherical cyclone separator includes a spherical shell 131, multiple cyclone guide plates 132 and a condensing demister 133. A flue gas inlet is provided on one side of the spherical shell 131, a gas phase outlet is provided on the other side, and a liquid phase outlet is provided at the bottom. The multiple cyclone guide plates 132 are respectively installed on the inner wall of the spherical shell 131. The intervals between the multiple cyclone guide plates 132 are used to guide the incoming flue gas absorption liquid mixture into a cyclone state. The condensing demister 133 is installed at the gas phase outlet and protrudes into the interior of the spherical shell 131. The gas phase outlet of the spherical shell 131 is connected to the secondary flue gas absorption inlet of the concentration absorption tower 2.

[0053] The spherical shell is equipped with swirl blades at the flue gas inlet, so that the flue gas enters the spherical separator in a swirling state. The spherical shell 131 is equipped with multiple swirl guide plates 132, and a swirl channel is formed between adjacent swirl guide plates 132. The rotation radius of the flue gas and absorbent mixture gradually increases in the early stage of the swirl. After passing through the middle of the spherical shell 131, the rotation radius gradually decreases, and the swirl diameter gradually changes. The pressure along the spherical surface is greater than that near the centerline, achieving inlet and outlet gas diversion within a small space, reducing the proportion of direct short-circuit gas outflow. The internal swirling gas and the mainstream return gas enhance the mixing uniformity of the absorbent and flue gas, thereby improving the CO2 recovery rate. The condenser demister 133 protrudes into the interior of the spherical shell 131, generally with the protrusion reaching one-quarter to one-third of the diameter of the spherical shell 131. The condenser array plates of the condenser demister 133 are V-shaped plates, and the different layers of V-shaped plates are installed in a staggered manner, which can effectively condense the droplets, causing them to aggregate, grow, and finally fall.

[0054] Example 3, the condensation crystallization device includes a condensation crystallization tank 141, a chiller 142, a cold water coil 143 and a high-speed centrifugal separator 144. The top opening of the condensation crystallization tank 141 is connected to the liquid phase outlet at the bottom of the spherical shell 131, the cold water coil 143 is installed around the inner wall of the condensation crystallization tank 141, the circulating water inlet and outlet of the chiller 142 are connected to the two ends of the cold water coil 143, a condensation channel is formed in the cold water coil 143, and the inlet of the high-speed centrifugal separator 144 is connected to the bottom opening of the condensation crystallization tank 141 through a pipeline, which is used to perform solid-liquid phase separation on the solid-liquid mixture falling from the condensation channel.

[0055] The condensation crystallization device is based on the chiller 142, which is a cold water coil 1435℃-10℃, so that the temperature of the absorption liquid in the condensation crystallization tank 141 is 10-15 degrees, and the liquid phase is condensed to obtain a solid product of sodium bicarbonate. During the condensation process, some absorption liquid remains in liquid state. The solid and liquid enter the high-speed centrifuge 144 together to achieve solid-liquid separation. The solid phase product is solid sodium bicarbonate, and the liquid absorption liquid flows into the subsequent absorption liquid circulation device for reuse, thereby efficiently realizing CO2 resource recovery, and the absorption liquid can be recycled repeatedly.

[0056] In Example 4, the concentration absorption tower 2 includes a first tower body 21, a cyclone plate demister 22 and a multi-stage spray device 23. The multi-stage spray device 23 is installed in the middle of the first tower body 21. The cyclone plate demister 22 is installed in the first tower body 21 and is located above the multi-stage spray device 23. A secondary flue gas absorption inlet is provided on one side of the bottom of the first tower body 21, and a secondary flue gas outlet is provided on the top.

[0057] The concentration absorption tower 2 uses a multi-stage spray device 23 to achieve secondary absorption of CO2, using an atmospheric liquid ratio multi-stage spray with a gas-liquid ratio of 1-20m 3 Liquid / 1000m 3The flue gas has no filler and the CO2 content is very low after secondary absorption. It enters the deep absorption tower 3 after being defogged by the cyclone plate demister 22.

[0058] Example 5, the deep absorption tower 3 includes a second tower body 31, a multi-stage packing absorption device 32 and a demister 33. A residual flue gas absorption inlet is provided on one side of the bottom of the second tower body 31, and an exhaust gas outlet is provided on the top. The multi-stage packing absorption device 32 is installed in the middle of the second tower body 31. The demister 33 is installed in the second tower body 31 and is located above the multi-stage packing absorption device 32. The residual flue gas absorption inlet is connected to the secondary flue gas outlet of the first tower body 21 through a pipeline.

[0059] The deep absorption tower 3 adopts a multi-stage filler absorption device 32, with no limit on filler type and a gas-liquid ratio of 1-20m 3 Liquid / 1000m 3 Gas, can effectively absorb CO2 residue.

[0060] Example 6, the absorption liquid circulation device includes a second tower body absorption liquid tank 41, a first tower body absorption liquid tank 42, a spray absorption liquid adjustment device and an atomizer 44, the liquid outlet of the second tower body absorption liquid tank 41 is connected to the liquid inlet of the multi-stage packing absorption device 32 of the deep absorption tower 3 through a water pump and a pipeline, providing absorption liquid for the multi-stage packing absorption device 32, and is connected to the liquid inlet of the first tower body absorption liquid tank 42 through a water pump and a pipeline to replenish the absorption liquid for the first tower body absorption liquid tank 42, and the liquid outlet of the first tower body absorption liquid tank 42 is connected to the liquid inlet of the multi-stage spray device 23 through a water pump and a pipeline to provide absorption liquid for the multi-stage spray device 23;

[0061] The spray absorption liquid adjustment device includes a stirring tank 431, an agitator 432 and a heater. The inlet of the stirring tank 431 is connected to the liquid phase outlet of the second tower absorption liquid tank 41 and the high-speed centrifuge 144 through a pipeline. The agitator 432 and the heater are respectively installed in the stirring tank 431. The inlet of the atomizer 44 is connected to the outlet at the bottom of the stirring tank 431 through a pipeline and a water pump. The outlet of the atomizer 44 is connected to the inlet of the multi-point spray array 12 through a pipeline.

[0062] In Example 7, the second tower absorption liquid tank 41 and the first tower absorption liquid tank 42 are respectively provided with electronic liquid level gauges, and absorption liquid is added to the second tower absorption liquid tank 41 and the first tower absorption liquid tank 42 according to the liquid levels monitored by the electronic liquid level gauges.

[0063] In Example 8, the absorption liquid added to the second tower absorption liquid box 41 is a mixture of sodium carbonate and sodium hydroxide.

[0064] The entire absorption liquid circulation device only needs to add absorption liquid at the inlet of the second tower body absorption liquid tank 41. The absorption liquid can be a mixture of sodium carbonate and sodium hydroxide. The replenishment process can use an automated adding device. When the liquid level monitored by the electronic liquid level meter is lower than the set liquid level, sodium carbonate, sodium hydroxide and water are added to ensure the final CO2 absorption efficiency.

[0065] In Example 9, the multiple groups of nozzles of the multi-point spray array 12 are directed toward the flue gas duct 100 .

[0066] The structure of the multi-point spray array 12 can be a multi-layer nozzle array with multiple groups of nozzles installed. The multiple groups of nozzles facing the flue gas duct 100 can make the spray direction opposite to the flue gas flow direction, increase the relative velocity of gas and liquid, and increase the CO2 absorption rate.

[0067] Example 10, a method for recovering CO2 from combustion flue gas, using a CO2 recovery device for recovering CO2 from combustion flue gas, comprising the following steps:

[0068] Step 1: The flue gas to be recovered from CO2 is introduced into the air inlet pipe 11 from the flue gas pipe 100, and the multi-point spray array 12 sprays atomized absorption liquid to form a gas-liquid mixture which enters the spherical shell 131;

[0069] Step 2: The swirl flow is guided by the multiple swirl guide plates 132. The initial swirl radius gradually increases, and after passing through the middle of the spherical shell 131, the swirl radius gradually decreases. The condenser demister 133 absorbs the droplets, and the droplets gradually grow larger and fall. The gas-phase flue gas after gas-liquid separation enters the concentration absorption tower 2 through the gas phase outlet and the secondary flue gas absorption inlet in sequence and moves upward.

[0070] In step 3, the ascending flue gas contacts the absorption liquid sprayed by the multi-stage spray device 23, absorbs the residual CO2 again, passes through the cyclone plate demister 22, enters the first tower body 21 through the secondary flue gas outlet and the residual flue gas absorption inlet, and ascends. After passing through the multi-stage packing absorption device 32, it is finally discharged through the exhaust outlet and pipeline under the absorption effect;

[0071] In step 4, the liquid phase after gas-liquid separation falls into the condensation crystallization tank 141. Under the cooling effect of the cold water coil 143, a solid-liquid mixture is formed and enters the high-speed centrifuge 144. The high-speed centrifuge 144 separates the solid-liquid phase of the solid-liquid mixture falling from the condensation channel. The solid phase is the CO2 resource recovery product, and the liquid phase enters the spray absorption liquid adjustment device, which is heated and stirred to provide absorption liquid for the atomizer 44.

[0072] In step 5, the CO2 absorbed in the absorption liquid in the concentrated absorption tower 2 and the deep absorption tower 3 in step 3 is finally passed through the absorption liquid circulation device and again through the multi-point spray array 12 to enter the atomizing cyclone device.

[0073] A specific application example involves CO2 recovery from flue gas at an aluminum ash recycling plant. The furnace is a rotary kiln, fueled by natural gas. The original flue gas purification process was: cyclone dust removal → SCR denitrification → bag filter → wet desulfurization. The operating flue gas volume was approximately 24,000 cubic meters per hour.

[0074] After being treated by the above-mentioned environmental protection facilities, the average concentration of CO2 in the flue gas is about 9%.

[0075] The method for resource recovery of CO2 in combustion flue gas of the present invention is used to recover carbon dioxide from flue gas, and the processing conditions are as follows: (1) absorption crystallization section: the absorption liquid spraying volume is 20 cubic meters per hour, and the sodium carbonate concentration in the absorption liquid is about 10%; (2) concentration absorption tower: the absorption liquid circulating spraying volume is 80 cubic meters per hour, and the sodium carbonate concentration in the absorption liquid is about 15%; (3) deep absorption tower: the absorption liquid circulating spraying volume is 60 cubic meters per hour, the sodium carbonate concentration in the absorption liquid is about 18%, and the sodium hydroxide concentration is about 3%.

[0076] After absorption treatment, the CO2 removal rate in the flue gas is about 97%, and the average CO2 concentration at the outlet is about 1.8g / cubic meter. The purity of the recovered sodium bicarbonate exceeds 95%, and the impurities are mainly sodium carbonate, accounting for about 4%.

[0077] The above are all preferred embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A CO2 resource recovery device in combustion flue gas, characterized by: It includes an atomizing cyclone device, a condensation crystallization device, a concentration absorption tower (2), a deep absorption tower (3) and an absorption liquid circulation device; The atomizing cyclone device includes an air inlet pipe (11), a multi-point spray array (12) and a spherical cyclone separator. The flue gas pipe (100) is connected to the air inlet pipe (11). The multi-point spray array (12) is installed on the inner wall of the air inlet pipe (11) and is located at one end connected to the flue gas pipe (100). The spherical cyclone separator is provided with a flue gas inlet, a gas phase outlet after gas-liquid phase separation and a liquid phase outlet. The flue gas inlet is connected to the other end of the air inlet pipe (11). The spherical cyclone separator guides the flue gas absorption liquid mixture into a cyclone state and separates the gas and liquid phases in the cyclone state. The condensation crystallization device is installed at the bottom liquid phase outlet of the spherical cyclone separator. The inlet of the condensation crystallization device is connected to the liquid phase outlet. After the liquid phase is condensed and crystallized, high-speed solid-liquid separation is performed to obtain a solid phase product and a liquid absorption liquid. The liquid absorption liquid is then connected to the inlet of the multi-point spray array (12) after temperature adjustment and atomization. The concentration absorption tower (2) is provided with a secondary flue gas absorption inlet and a secondary flue gas outlet. The gas phase outlet of the spherical cyclone separator is connected to the secondary flue gas absorption inlet. The flue gas after multi-stage spray absorption is discharged through the secondary flue gas outlet. The deep absorption tower (3) is provided with a residual flue gas absorption inlet and an exhaust gas outlet. The residual flue gas absorption inlet is connected to the secondary flue gas outlet of the concentrated absorption tower (2). The exhaust gas absorbed by the multi-stage filler is discharged from the exhaust gas outlet. The absorption liquid circulation device provides CO2 absorption liquid to the atomizing cyclone device, the concentration absorption tower (2) and the deep absorption tower (3); The spherical cyclone separator comprises a spherical shell (131), a plurality of cyclone guide plates (132) and a condensation demister (133). A flue gas inlet is provided on one side of the spherical shell (131), a gas phase outlet is provided on the corresponding other side, and a liquid phase outlet is provided at the bottom. The plurality of cyclone guide plates (132) are respectively mounted on the inner wall of the spherical shell (131). The intervals between the plurality of cyclone guide plates (132) are used to guide the incoming flue gas absorption liquid mixture into a cyclonic state. The condensation demister (133) is mounted at the gas phase outlet and protrudes into the interior of the spherical shell (131). The gas phase outlet of the spherical shell (131) is connected to the secondary flue gas absorption inlet of the concentration absorption tower (2). The rotation radius of the flue gas absorption liquid mixture gradually increases in the initial stage of the swirl, and gradually decreases after passing through the middle of the spherical shell (131), and the swirl diameter gradually changes.

2. The CO2 resource recovery device in combustion flue gas according to claim 1 is characterized in that: The condensation crystallization device includes a condensation crystallization tank (141), a chiller (142), a cold water coil (143) and a high-speed centrifugal separator (144), wherein the top opening of the condensation crystallization tank (141) is connected to the liquid phase outlet at the bottom of the spherical shell (131), the cold water coil (143) is installed around the inner wall of the condensation crystallization tank (141), the circulating water inlet and outlet of the chiller (142) are connected to the two ends of the cold water coil (143), a condensation channel is formed in the cold water coil (143), and the inlet of the high-speed centrifugal separator (144) is connected to the bottom opening of the condensation crystallization tank (141) through a pipeline, so as to perform solid-liquid phase separation on the solid-liquid mixture falling from the condensation channel.

3. The CO2 resource recovery device in combustion flue gas according to claim 2 is characterized in that: The concentration absorption tower (2) comprises a first tower body (21), a cyclone plate demister (22) and a multi-stage spray device (23), wherein the multi-stage spray device (23) is installed in the middle of the first tower body (21), the cyclone plate demister (22) is installed in the first tower body (21) and is located above the multi-stage spray device (23), and a secondary flue gas absorption inlet is provided on one side of the bottom of the first tower body (21), and a secondary flue gas outlet is provided on the top.

4. The CO2 resource recovery device in combustion flue gas according to claim 3 is characterized by: The deep absorption tower (3) includes a second tower body (31), a multi-stage packing absorption device (32) and a demister (33). A residual flue gas absorption inlet is provided on one side of the bottom of the second tower body (31), and an exhaust gas outlet is provided on the top. The multi-stage packing absorption device (32) is installed in the middle of the second tower body (31). The demister (33) is installed in the second tower body (31) and is located above the multi-stage packing absorption device (32). The residual flue gas absorption inlet is connected to the secondary flue gas outlet of the first tower body (21) through a pipeline.

5. The CO2 resource recovery device in combustion flue gas according to claim 4 is characterized in that: The absorption liquid circulation device comprises a second tower body absorption liquid tank (41), a first tower body absorption liquid tank (42), a spray absorption liquid adjustment device and an atomizer (44); the liquid outlet of the second tower body absorption liquid tank (41) is connected to the liquid inlet of the multi-stage packing absorption device (32) of the deep absorption tower (3) through a water pump and a pipeline, providing absorption liquid for the multi-stage packing absorption device (32); and the liquid outlet of the second tower body absorption liquid tank (41) is connected to the liquid inlet of the first tower body absorption liquid tank (42) through a water pump and a pipeline, replenishing absorption liquid for the first tower body absorption liquid tank (42); the liquid outlet of the first tower body absorption liquid tank (42) is connected to the liquid inlet of the multi-stage spraying device (23) through a water pump and a pipeline, providing absorption liquid for the multi-stage spraying device (23); The spray absorption liquid adjustment device includes a stirring tank (431), an agitator (432) and a heater. The inlet of the stirring tank (431) is connected to the second tower absorption liquid tank (41) and the liquid phase outlet of the high-speed centrifugal separator (144) through a pipeline. The agitator (432) and the heater are respectively installed in the stirring tank (431). The inlet of the atomizer (44) is connected to the outlet at the bottom of the stirring tank (431) through a pipeline and a water pump. The outlet of the atomizer (44) is connected to the inlet of the multi-point spray array (12) through a pipeline.

6. The CO2 resource recovery device in combustion flue gas according to claim 5 is characterized in that: The second tower absorption liquid tank (41) and the first tower absorption liquid tank (42) are respectively provided with electronic liquid level gauges, and absorption liquid is added to the second tower absorption liquid tank (41) and the first tower absorption liquid tank (42) according to the liquid levels monitored by the electronic liquid level gauges.

7. The CO2 resource recovery device in combustion flue gas according to claim 6 is characterized in that: The absorption liquid added to the second tower absorption liquid box (41) is a mixture of sodium carbonate and sodium hydroxide.

8. The CO2 resource recovery device in combustion flue gas according to claim 1 is characterized in that: The multiple groups of nozzles of the multi-point spray array (12) are directed toward the flue gas duct (100).

9. A method for recovering CO2 from combustion flue gas, characterized by: The CO2 resource recovery device for combustion flue gas according to claim 8 is used to recover CO2 from combustion flue gas, comprising the following steps: Step 1: The flue gas to be recovered from CO2 is introduced into the air inlet pipe (11) from the flue gas pipe (100), and the multi-point spray array (12) sprays the atomized absorption liquid to form a gas-liquid mixture which enters the spherical shell (131); Step 2: The swirl is guided by the multiple swirl guide plates (132). The initial rotation radius of the swirl gradually increases, and after passing through the middle of the spherical shell (131), the rotation radius gradually decreases. The condenser demister (133) absorbs the droplets, and the droplets gradually become larger and fall. The gas phase flue gas after gas-liquid separation enters the concentration absorption tower (2) through the gas phase outlet and the secondary flue gas absorption inlet in sequence and moves upward. Step 3, the ascending flue gas contacts the absorption liquid sprayed by the multi-stage spray device (23), absorbs the residual CO2 again, passes through the cyclone plate demister (22), enters the first tower body (21) through the secondary flue gas outlet and the residual flue gas absorption inlet, and ascends. After passing through the multi-stage packing absorption device (32), it is finally discharged through the tail gas outlet and pipeline under the absorption effect; Step 4, the liquid phase after gas-liquid separation falls into the condensation crystallization tank (141), and under the cooling effect of the cold water coil (143), a solid-liquid mixture is formed and enters the high-speed centrifugal separator (144). The high-speed centrifugal separator (144) separates the solid-liquid mixture falling from the condensation channel into solid-liquid phases. The solid phase is the CO2 resource recovery product, and the liquid phase enters the spray absorption liquid adjustment device, and after heating and stirring, provides the absorption liquid for the atomizer (44); In step 5, in step 3, the CO2 absorbed in the absorption liquid in the concentrated absorption tower (2) and the deep absorption tower (3) finally passes through the absorption liquid circulation device and again passes through the multi-point spray array (12) to enter the atomizing cyclone device.

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