A method and system for carbon neutrality, carbon emission reduction, recycling, and resource recovery.

Abstract

This invention provides a carbon neutrality, carbon emission reduction, recovery, and resource utilization method, comprising the following steps: Step S1: The recovered carbon dioxide waste gas is subjected to alkaline scrubbing in an alkaline scrubbing tower, and the scrubbed waste gas enters a bag filter for dust removal; Step S2: The dust-removed carbon dioxide waste gas is absorbed in a rotary absorption tower, and the unabsorbed carbon dioxide waste gas enters the compressor; Step S3: The compressor compresses the carbon dioxide waste gas, and the waste gas is first mixed with supplemented off-gas at the compressor outlet, and then mixed with the tail gas from the ammonium carbonate synthesis tower, and the mixed waste gas is input into the ammonium carbonate synthesis tower; Step S4: The ammonium carbonate synthesis tower absorbs the carbon dioxide waste gas to generate ammonium bicarbonate solid suspension, which is sent to a centrifuge for separation, and the separated ammonium bicarbonate solid is dried by a dryer. This invention captures and reuses carbon dioxide waste gas from industrial flue gas, achieving the repeated reuse of carbon dioxide resources.

Description

Technical Field

[0001] This invention relates to the field of carbon neutrality and emission reduction technology, and in particular to a method and system for carbon neutrality, carbon emission reduction, recycling, and resource recovery. Background Technology

[0002] Currently, the main technologies for dual-carbon governance both domestically and internationally include:

[0003] 1. Solvent absorption technology;

[0004] Using solvents to absorb and desorb carbon dioxide can achieve a carbon dioxide concentration of over 98%. However, this method is only suitable for recovering carbon dioxide from low-concentration waste gas, and the process is complex and costly.

[0005] 2. Pressure Swing Adsorption Technology;

[0006] Solid adsorbents are used to adsorb carbon dioxide from a mixed gas, achieving concentrations of over 60%. This method is only suitable for removing carbon dioxide from the shift gas of fertilizer plants, and is unsuitable for use as a product if the carbon dioxide concentration is too low.

[0007] 3. Organic membrane separation technology;

[0008] Using hollow fiber membranes to separate carbon dioxide under high pressure is only suitable for situations where the gas source is clean and the required carbon dioxide concentration is no higher than 90%.

[0009] 4. Catalytic combustion technology;

[0010] This method uses a catalyst and pure oxygen to convert combustible impurities in carbon dioxide into carbon dioxide and water. However, this method can only remove combustible impurities, is energy-intensive and costly, and has been phased out.

[0011] 5. Low-temperature distillation technology;

[0012] It is suitable for occasions where the carbon dioxide concentration in the gas source is above 90%, the product purity requirement is high, the equipment is large, the energy consumption is high, and liquefaction storage and transportation are also required.

[0013] 6. Carbon dioxide geological sequestration technology;

[0014] Underground saline aquifers are recognized as ideal locations for large-scale carbon dioxide storage in the future. However, current carbon dioxide geological sequestration technology lacks reliability and long-term sustainability. Once carbon dioxide leaks, it will have an impact on the surrounding ecological environment.

[0015] 7. "Fossil Energy + CCUS" low-carbon emission technology;

[0016] Currently, many low-carbon emission technologies are still in the laboratory stage. Due to high investment costs and varying levels of policy support, the overall development of CCUS globally has been relatively slow.

[0017] 8. Direct air carbon capture technology;

[0018] The process of capturing carbon directly from the air, rather than from factory chimneys, is called "direct air capture." This technology faces challenges such as large land area requirements and high investment costs for carbon emission treatment facilities. Because carbon is captured directly from the air, where the carbon content is relatively low, the equipment's processing efficiency is low, and the treatment cycle is long.

[0019] Therefore, this invention proposes a method and system for carbon neutrality, carbon emission reduction, recycling, and resource recovery. Summary of the Invention

[0020] To address the shortcomings of existing technologies, the present invention aims to provide a carbon neutrality, carbon emission reduction, recycling, and resource utilization method and system. This invention utilizes a highly efficient composite treatment system to capture and reuse carbon dioxide emissions from industrial flue gas, achieving the goals of carbon dioxide resource reuse, energy conservation, and emission reduction. This provides strong technical support for accelerating the realization of global carbon neutrality and carbon peaking.

[0021] To achieve the above objectives, the present invention provides a method for carbon neutrality, carbon emission reduction, recycling, and resource recovery, comprising the following steps:

[0022] Step S1: The recovered carbon dioxide waste gas is subjected to alkaline washing in an alkaline scrubbing tower, and the waste gas after alkaline washing enters a bag filter for dust removal.

[0023] Step S2: The carbon dioxide waste gas after dust removal is absorbed by the rotary absorption tower. The waste liquid formed after the carbon dioxide is absorbed is condensed by the condenser and stored in the condensate storage tank. The unabsorbed carbon dioxide waste gas enters the compressor. Step S3: The compressor compresses the carbon dioxide waste gas. The compressed waste gas is first mixed with the supplemented off-gas at the compressor outlet, and then mixed with the tail gas from the ammonium carbonate synthesis tower. The mixed waste gas is then fed into the ammonium carbonate synthesis tower.

[0024] Step S4: The ammonium carbonate synthesis tower absorbs carbon dioxide waste gas to generate ammonium bicarbonate solid suspension. The ammonium bicarbonate solid suspension is cooled by a cooling tower, and the cooled ammonium bicarbonate solid suspension is sent to a centrifuge for separation. The separated ammonium bicarbonate solid is dried by a dryer.

[0025] Furthermore, the alkaline scrubbing tower for alkaline scrubbing carbon dioxide waste gas specifically includes the following steps:

[0026] Step 1: Carbon dioxide waste gas enters the alkaline scrubbing tower. When the airflow passes through the blades, it generates rotation and centrifugal motion. The absorbent liquid is evenly distributed to each blade through the middle blind plate, forming a thin liquid layer.

[0027] Step 2: The blades and the upward rotating airflow create a rotational and centrifugal effect, spraying the liquid into fine droplets that are then flung towards the tower wall;

[0028] Step 3: The absorbent enters from the top of the tower and exits from the bottom. The airflow and absorbent move relative to each other inside the tower, forming a water film with a large surface area in the structural part of the swirl plate.

[0029] Step 4: The absorbent liquid of each layer falls into the collection tank at the edge through the centrifugal force of the cyclone, and then enters the next tray through the guide pipe to carry out the absorption of the next layer.

[0030] Further, in step S1, the exhaust gas after alkaline washing enters the bag filter equipment. The carbon dioxide exhaust gas enters the ash hopper through the air inlet. Due to the rapid expansion of the gas volume, some of the coarser dust particles fall into the ash hopper due to inertia or natural settling. Most of the remaining dust particles rise with the airflow and enter the bag chamber. After being filtered by the dust collector filter bag, the dust particles are retained on the outside of the filter bag. The purified gas enters the upper box from the inside of the filter bag and is then discharged into the atmosphere through the valve plate hole and the exhaust port.

[0031] Furthermore, in step S2, the rotary absorber performs the carbon dioxide waste gas absorption process as follows:

[0032] Step 21: The carbon dioxide-containing exhaust gas after dust removal is fully mixed in a buffer bottle and then enters the rotary absorption tower. Under pressure, it passes through a uniform air distribution plate and enters the packing layer filled with organic polymer sieves.

[0033] Step 22: The liquid is sprayed into the inner edge of the packing layer as the rotating shaft rotates in the inner cavity of the rotating absorption tower. Under the action of centrifugal force, it is pushed outward to the outer edge of the packing. During the outward pushing process, the liquid is dispersed and broken into droplets with continuously renewed surface area by the packing.

[0034] Step 23: After the liquid is thrown onto the outer shell by the rotating shaft and collected, it leaves the rotating packed bed through the liquid outlet pipe. The concentration of carbon dioxide exhaust gas discharged from the top of the tower is measured by chemical absorption method. The treatment efficiency of the rotating absorption device is calculated by the concentration of carbon dioxide exhaust gas before and after the process.

[0035] Step 24: Using external equipment, the packing layer of the organic polymer sieve is divided into absorption, regeneration, and cooling zones. Water vapor in the range of 150-180°C is supplied to the regeneration zone to obtain highly concentrated carbon dioxide.

[0036] Furthermore, the carbon dioxide exhaust gas from the rotary absorption tower passes through the raw material gas-water separator to the inlet of the CO2 compressor, where it is compressed to 0.5-0.9 MPa and mixed with the off-gas from the rotary absorption tower at the compressor outlet. This mixture is then combined with the carbon dioxide exhaust gas from the top of the ammonium carbonate synthesis tower, which passes through the tail gas-water separator to the tail gas recirculation compressor and is compressed to 0.5-0.9 MPa for recycling, to form a mixed gas that enters the carbonization process.

[0037] Furthermore, the carbonization process is specifically as follows:

[0038] The prepared mixed gas enters the bottom of the main column of the dual-series parallel carbonization tower;

[0039] Carbonization liquid from the carbonization pump is added to the upper part of the main carbonization tower and comes into countercurrent bubble contact with the mixed gas to absorb carbon dioxide. 60% to 95% of the carbon dioxide waste gas is absorbed to form ammonium bicarbonate crystals, and 5% to 40% of the carbon dioxide waste gas enters the carbonization auxiliary tower from the top of the main carbonization tower.

[0040] In the upper part of the main carbonization tower's recovery and cleaning section, soft water cooled to 20°C by a soft water cooler (02E0201) is added to the upper part of the recovery and cleaning tower. In the recovery and cleaning section, the water passes through a sieve plate and enters the absorption chamber to recover NH and CO2 from the gas, ensuring the tail gas meets quality standards. After absorption, the main carbonization tower generates ammonium bicarbonate crystals, most of which are sent to subsequent processes as a suspension. A small amount of crystals adheres to the tower wall and cooling water tank, affecting heat exchange. During production, the main and auxiliary carbonization towers are switched every 1-2 shifts. The main carbonization tower with crystals is replaced with the auxiliary tower, where concentrated ammonia water is used for bubbling cleaning to dissolve the crystallized carbon.

[0041] The main carbonation tower and the auxiliary carbonation tower together constitute the ammonium carbonate synthesis tower.

[0042] Further, in step S4, the generated ammonium bicarbonate solid suspension, the suspension containing crystals, is taken out from the bottom of the ammonium bicarbonate synthesis tower, sent to a thickener, and flows into a centrifuge for separation, so that the ammonium bicarbonate crystals are separated from the mother liquor, and wet ammonium bicarbonate product is obtained.

[0043] A carbon neutrality, carbon emission reduction, recovery, and resource utilization system includes an alkaline scrubbing tower, a bag filter, a rotary absorption tower, a compressor, a condenser, and an ammonium carbonate synthesis tower. The alkaline scrubbing tower is used to scrub carbon dioxide waste gas drawn in by a blower. The bag filter removes dust from the scrubbed waste gas. The waste gas after dust removal enters the rotary absorption tower, where it absorbs carbon dioxide. The absorbed waste liquid is condensed by the condenser, and the unabsorbed waste gas enters the compressor. The compressed waste gas then enters the ammonium carbonate synthesis tower, where the ammonium bicarbonate solid suspension generated is sent to a centrifuge for separation. The separated ammonium bicarbonate solid is dried by a dryer and then collected.

[0044] Furthermore, the compressor's tail end is connected to the top of both the rotary absorption tower and the ammonium carbonate synthesis tower.

[0045] Furthermore, the top of the rotary absorption tower is connected to an exhaust chimney, and the ammonium carbonate synthesis tower is connected to a liquid ammonia storage tank.

[0046] The beneficial effects of this invention are:

[0047] 1. This invention can fully utilize air to use carbon dioxide as a raw material, thereby achieving carbon dioxide emission reduction and resource reuse.

[0048] 2. This invention uses an aqueous solution of MDEA with a small amount of TETA as an absorbent. This mixed amine absorption system has the characteristics of both chemical and physical absorption. In the early stage of the reaction, chemical absorption is dominant, and the higher the concentration of the mixed amine solution, the faster the reaction rate.

[0049] 3. Traditional gas-liquid countercurrent contact towers have low flooding points and small effective contact areas per unit volume. Therefore, rotating absorption towers are used instead, with rotating packed beds, to greatly enhance heat transfer and reaction processes by utilizing centrifugal force. Attached Figure Description

[0050] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0051] Figure 1 This is a flowchart of a carbon neutrality, carbon emission reduction, recycling, and resource recovery method and system according to the present invention.

[0052] In the diagram: 1. Fan; 2. Alkali scrubbing tower; 3. Bag filter; 4. Rotary absorption tower; 5. Exhaust chimney; 6. Centrifuge; 7. Dryer; 8. Cooling tower; 9. Ammonium carbonate synthesis tower; 10. Compressor; 11. Liquid ammonia storage tank; 12. Condensate storage tank; 13. Condenser. Detailed Implementation

[0053] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0054] In this invention, please refer to Figure 1 A carbon neutrality, carbon emission reduction, recovery, and resource utilization system includes an alkaline scrubbing tower 2, a bag filter 3, a rotary absorption tower 4, a compressor 10, a condenser 13, and an ammonium carbonate synthesis tower 9. The alkaline scrubbing tower 2 is used to perform alkaline scrubbing on the carbon dioxide waste gas sucked in by the suction fan 1. The bag filter 3 removes dust from the alkaline scrubbed waste gas. The waste gas after dust removal enters the rotary absorption tower 4, where it absorbs the carbon dioxide in the waste gas. The absorbed waste liquid is condensed by the condenser 13, and the unabsorbed waste gas enters the compressor 10 through the condenser 13. The waste gas compressed by the compressor 10 enters the ammonium carbonate synthesis tower 9, where the ammonium bicarbonate solid suspension generated by the ammonium carbonate synthesis tower 9 is sent to a centrifuge 6 for separation. The separated ammonium bicarbonate solid is dried by a dryer 7 and then collected.

[0055] The compressor 10 is connected to the top of the rotary absorption tower 4 and the ammonium carbonate synthesis tower 9 respectively. The exhaust gas supplemented by the rotary absorption tower 4 is mixed at the outlet of the compressor 10. The carbon dioxide exhaust gas at the top of the ammonium carbonate synthesis tower 9 is compressed to 0.5-0.9 MPa by the exhaust gas recirculation compressor 10 through the exhaust gas water separator and mixed together with the exhaust gas for recycling. The top of the rotary absorption tower 4 is connected to the exhaust chimney 5, which discharges the treated gas. The ammonium carbonate synthesis tower 9 is connected to the liquid ammonia storage tank 11, through which liquid ammonia is supplied.

[0056] This invention discloses a method for carbon neutrality, carbon emission reduction, recycling, and resource recovery, comprising the following steps:

[0057] Step S1: The recovered carbon dioxide waste gas is subjected to alkaline washing in alkaline scrubbing tower 2, and the waste gas after alkaline washing enters bag filter 3 for dust removal.

[0058] When performing alkaline scrubbing on carbon dioxide waste gas, alkaline scrubbing tower 2 specifically includes the following steps:

[0059] Step 1: Carbon dioxide waste gas enters the interior of alkaline scrubbing tower 2. When the airflow passes through the blades, it generates rotation and centrifugal motion. The absorbent liquid is evenly distributed to each blade through the intermediate blind plate, forming a thin liquid layer.

[0060] Step 2: The blades and the upward rotating airflow create a rotational and centrifugal effect, spraying the liquid into fine droplets that are then flung towards the tower wall;

[0061] Step 3: The absorbent enters from the top of the tower and exits from the bottom. The airflow and the absorbent move relative to each other inside the tower, forming a water film with a large surface area in the structural part of the swirl plate, which greatly improves the absorption effect.

[0062] Step 4: The absorbent liquid of each layer falls into the collection tank at the edge through the centrifugal force of the cyclone, and then enters the next tray through the guide pipe to carry out the absorption of the next layer.

[0063] The main mechanisms are inertial collisions between dust particles and liquid droplets, centrifugal separation, and liquid film adhesion. Due to its large opening ratio, this type of tray allows high-speed airflow, resulting in higher load, larger processing capacity, lower pressure drop, and greater operational flexibility. Its gas-liquid contact time is short, making it suitable for gas-phase diffusion control processes, such as direct gas-liquid contact heat transfer and rapid reaction absorption. The pretreatment absorbent is sodium hydroxide, which utilizes the properties of alkaline solutions to neutralize acidic impurities in the combustion exhaust gas.

[0064] After being washed with alkaline solution, the exhaust gas enters the bag filter 3. Carbon dioxide exhaust gas enters the ash hopper through the inlet. Due to the rapid expansion of the gas volume, some of the coarser dust particles fall into the ash hopper due to inertia or natural settling. Most of the remaining dust particles rise with the airflow and enter the bag chamber. After being filtered by the dust collection filter bags, the dust particles are retained on the outside of the filter bags. The purified gas enters the upper chamber from the inside of the filter bags and is then discharged into the atmosphere through the valve plate holes and the exhaust port, thereby achieving the purpose of dust removal.

[0065] Step S2: The carbon dioxide waste gas after dust removal is absorbed by the rotary absorption tower 4, and the waste liquid formed after the carbon dioxide is absorbed is condensed by the condenser 13 and stored in the condensate storage tank 12. The unabsorbed carbon dioxide waste gas enters the compressor 10.

[0066] The process of carbon dioxide waste gas absorption in rotary absorption tower 4 is as follows:

[0067] Step 21: The carbon dioxide-containing exhaust gas after dust removal is fully mixed in a buffer bottle and then enters the rotary absorption tower 4. Under pressure, it passes through the uniform air distribution plate and enters the packing layer filled with organic polymer sieves.

[0068] Step 22: The liquid is sprayed into the inner edge of the packing layer as the rotating shaft rotates in the inner cavity of the rotating absorption tower 4. Under the action of centrifugal force, it is pushed outward to the outer edge of the packing. During the outward pushing process, the liquid is dispersed and broken into droplets with continuously renewed surface area by the packing.

[0069] Step 23: After the liquid is thrown onto the outer shell by the rotating shaft and collected, it leaves the rotating packed bed through the liquid outlet pipe. The concentration of carbon dioxide exhaust gas discharged from the top of the tower is measured by chemical absorption method. The treatment efficiency of the rotating absorption device is calculated by the concentration of carbon dioxide exhaust gas before and after the process.

[0070] Step 24: Using external equipment, the packing layer of the organic polymer sieve is divided into absorption, regeneration, and cooling zones. The cylindrical honeycomb absorbent inside the rotary absorption tower 4 rotates at a speed of 2-3 revolutions per minute. At the same time, water vapor in the range of 150-180°C is supplied to the regeneration zone to carry out the separation reaction of carbon dioxide absorbed by the corrugated absorbent, thereby obtaining highly concentrated carbon dioxide.

[0071] The high-temperature corrugated absorbent, which rotates from the regeneration zone to the cooling zone, is cooled to conditions favorable for the absorption reaction using air at less than 50°C. This constitutes the above-mentioned absorption-regeneration-cooling process, thereby simultaneously achieving the adsorption removal and regeneration concentration of carbon dioxide in a cylindrical absorbent.

[0072] The carbon dioxide exhaust gas from the rotary absorption tower 4 passes through the raw material gas-water separator to the inlet of the CO2 compressor 10. After being compressed to 0.7 MPa by the compressor 10, it is mixed with the off-gas from the rotary absorption tower 4 at the outlet of the compressor 10. Then, it is mixed with the carbon dioxide exhaust gas from the top of the ammonium carbonate synthesis tower 9, which passes through the tail gas-water separator to the tail gas recirculation compressor 10 and is compressed to 0.7 MPa for recycling.

[0073] Selection of carbon dioxide absorbent

[0074] Carbon dioxide separation technology depends on the state characteristics of the carbon dioxide to be captured, such as concentration, pressure, and flow rate. (For the characteristics of low carbon dioxide concentration, low partial pressure, and high impurity and oxygen content in combustion flue gas, most flue gas carbon dioxide is separated by amine solution method. Although MEA (monoethanolamine) and DEA (diethanolamine) solution methods are technically mature, they have disadvantages such as easy solvent degradation, strong corrosiveness, and high regeneration energy consumption. TEA (triethanolamine) and MDEA (N-methyldiethanolamine) solution methods have single selectivity, good stability, low regeneration heat, and basically no corrosion to equipment, but the absorption rate is relatively low. To accelerate the absorption and regeneration rate, we adopt a mixed organic amine absorption method with single-component organic amine as the main solvent and a small amount of activating component that can react strongly with carbon dioxide.)

[0075] The absorption mechanism of organic amine solutions is as follows:

[0076] The absorption of carbon dioxide by organic amine solutions mainly depends on the nitrogen atoms contained in the amine molecules. Amines dissociate in aqueous solutions, making the solution alkaline, which facilitates the reaction with gases like carbon dioxide, thus achieving the removal of carbon dioxide. Using an aqueous solution of MDEA with a small amount of TETA as the absorbent, this mixed amine absorption system combines the characteristics of both chemical and physical absorption. In the early stages of the reaction, chemical absorption is dominant, and the higher the concentration of the mixed amine solution, the faster the reaction rate. As the content of TETA in the solution decreases and the amount of carbon dioxide dissolved increases, the absorption rate decreases, exhibiting the characteristics of physical absorption by MDEA.

[0077] It should be noted that, after the concentrated ammonia water in the ammonium carbonate synthesis tower 9 absorbs the carbon dioxide waste gas, the gas containing 5% to 40% carbon dioxide waste gas re-enters the bottom of the ammonium carbonate synthesis tower 9. The carbon dioxide waste gas is then absorbed by the concentrated ammonia water in the carbonation sub-tower section of the ammonium carbonate synthesis tower 9, reducing the carbon dioxide waste gas content in the tail gas to less than 0.4%. The tail gas then enters the upper recovery and cleaning section of the ammonium carbonate synthesis tower 9. After the demineralized water in the cleaning section absorbs the carbon dioxide and cleans the NH3, the carbon dioxide content is less than 0.4% (Vol%) and the NH3 content is less than 0.07% (Vol%). The tail gas, with a pressure of 0.5 MPa, is then passed through the tail gas water separator to the tail gas recirculation compressor 10, where it is compressed to 0.7 MPa to form a mixed gas before being recycled back into the carbonation process.

[0078] Step S3: The compressor 10 compresses the carbon dioxide exhaust gas. The compressed exhaust gas is first mixed with the supplemented off-gas at the outlet of the compressor 10, and then mixed with the exhaust gas from the ammonium carbonate synthesis tower 9. The mixture is then fed into the ammonium carbonate synthesis tower 9.

[0079] The carbonization process is as follows:

[0080] The prepared mixed gas enters the bottom of the main column of the dual-series parallel carbonization tower;

[0081] Carbonization liquid from the carbonization pump is added to the upper part of the main carbonization tower and comes into countercurrent bubbling contact with the mixed gas to absorb carbon dioxide. 60% to 95% of the carbon dioxide waste gas is absorbed to form ammonium bicarbonate crystals, and 5% to 40% of the carbon dioxide waste gas enters the secondary carbonization tower from the top of the main carbonization tower. The carbonization pump model is 02P0201abc, and the carbonization liquid is a pre-carbonized liquid from the secondary carbonization tower.

[0082] In the upper part of the main carbonization tower's recovery and cleaning section, soft water cooled to 20°C by a soft water cooler is added and enters the upper part of the recovery and cleaning tower. In the recovery and cleaning section, it passes through a sieve plate and enters the absorption to recover NH and CO2 in the gas, ensuring that the tail gas is qualified. After absorption, the main carbonization tower generates ammonium carbonate crystals. The suspension is sent to the downstream section. A small amount of crystals adheres to the tower wall and cooling water tank, affecting the heat exchange of the water tank. During production, the main carbonization tower and the secondary carbonization tower are switched once every 1-2 shifts. The main carbonization tower with crystals is replaced as the secondary tower. The crystallized carbon is dissolved by bubbling cleaning with concentrated ammonia water inside. Water cooler model: 02E0201.

[0083] The main carbonation tower and the secondary carbonation tower together constitute the ammonium carbonate synthesis tower 9.

[0084] Step S4: Ammonium carbonate synthesis tower 9 absorbs carbon dioxide waste gas to generate ammonium bicarbonate solid suspension. The ammonium bicarbonate solid suspension is cooled by cooling tower 8. The cooled ammonium bicarbonate solid suspension is sent to centrifuge 6 for separation. The separated ammonium bicarbonate solid is dried by dryer 7.

[0085] The generated ammonium bicarbonate solid suspension, the suspension containing crystals, is taken out from the bottom of the ammonium bicarbonate synthesis tower 9 and sent to the thickener, then flows into the centrifuge 6 for separation, so that the ammonium bicarbonate crystals are separated from the mother liquor, and wet ammonium bicarbonate product is obtained.

[0086] One portion of the wet ammonium bicarbonate, as agricultural grade ammonium bicarbonate, is weighed and packaged via belt conveyor and sent to the finished product warehouse. The other portion of wet ammonium bicarbonate is fed into a hot air drying pipe via a screw conveyor. Hot air from an air blower and preheated by an air heater is introduced into the bottom of the hot air drying pipe. The dried ammonium bicarbonate is then conveyed by airflow to a cyclone separator for further separation to obtain food-grade ammonium bicarbonate. The food-grade ammonium bicarbonate is weighed and packaged via belt conveyor and sent to the finished product warehouse.

[0087] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for carbon neutrality, carbon emission reduction, recycling, and resource recovery, characterized in that, The method includes the following steps: Step S1: The recovered carbon dioxide waste gas is subjected to alkaline washing in an alkaline scrubbing tower, and the waste gas after alkaline washing enters a bag filter for dust removal. Step S2: The carbon dioxide waste gas after dust removal is absorbed by the rotary absorption tower, and the waste liquid formed after absorbing the carbon dioxide waste gas is condensed by the condenser and stored in the condensate storage tank. The unabsorbed carbon dioxide waste gas enters the compressor. Step S3: The compressor compresses the carbon dioxide exhaust gas. The compressed exhaust gas is first mixed with the supplemented off-gas at the compressor outlet, and then mixed with the exhaust gas from the ammonium carbonate synthesis tower. The mixed exhaust gas is then fed into the ammonium carbonate synthesis tower. Step S4: The ammonium carbonate synthesis tower absorbs carbon dioxide waste gas to generate ammonium bicarbonate solid suspension. The ammonium bicarbonate solid suspension is cooled by a cooling tower, and the cooled ammonium bicarbonate solid suspension is sent to a centrifuge for separation. The separated ammonium bicarbonate solid is dried by a dryer. In step S1, the exhaust gas after alkaline washing enters the bag filter equipment. The carbon dioxide exhaust gas enters the ash hopper through the air inlet. Due to the rapid expansion of the gas volume, some of the coarser dust particles fall into the ash hopper due to inertia or natural settling. Most of the remaining dust particles rise with the airflow and enter the bag chamber. After being filtered by the dust collector filter bag, the dust particles are retained on the outside of the filter bag. The purified gas enters the upper box from the inside of the filter bag and is then discharged into the atmosphere through the valve plate hole and the exhaust port. In step S2, the rotary absorber performs the carbon dioxide waste gas absorption process as follows: Step 21: The carbon dioxide-containing exhaust gas after dust removal is fully mixed in a buffer bottle and then enters the rotary absorption tower. Under pressure, it passes through a uniform air distribution plate and enters the packing layer filled with organic polymer sieves. Step 22: The liquid is sprayed into the inner edge of the packing layer as the rotating shaft rotates in the inner cavity of the rotating absorption tower. Under the action of centrifugal force, it is pushed outward to the outer edge of the packing. During the outward pushing process, the liquid is dispersed and broken into droplets with continuously renewed surface area by the packing. Step 23: After the liquid is thrown onto the outer shell by the rotating shaft and collected, it leaves the rotating packed bed through the liquid outlet pipe. The concentration of carbon dioxide exhaust gas discharged from the top of the tower is measured by chemical absorption method. The treatment efficiency of the rotating absorption device is calculated by the concentration of carbon dioxide exhaust gas before and after the process. Step 24: Using external equipment, the packing layer of the organic polymer sieve is divided into absorption, regeneration, and cooling zones. Water vapor in the range of 150-180°C is supplied to the regeneration zone to obtain highly concentrated carbon dioxide. Carbon dioxide exhaust gas from the rotary absorption tower passes through the raw material gas-water separator to the inlet of the CO2 compressor. After being compressed to 0.5-0.9 MPa by the compressor, it is mixed with the off-gas from the rotary absorption tower at the compressor outlet. Then, it is mixed with the carbon dioxide exhaust gas from the top of the ammonium carbonate synthesis tower, which passes through the tail gas-water separator to the tail gas recirculation compressor and is compressed to 0.5-0.9 MPa for recycling. The mixture is then introduced into the carbonization process. The carbonization process is as follows: The prepared mixed gas enters the bottom of the main column of the dual-series parallel carbonization tower; Carbonization liquid from the carbonization pump is added to the upper part of the main carbonization tower and comes into countercurrent bubble contact with the mixed gas to absorb carbon dioxide. 60% to 95% of the carbon dioxide waste gas is absorbed to form ammonium bicarbonate crystals, and 5% to 40% of the carbon dioxide waste gas enters the carbonization auxiliary tower from the top of the main carbonization tower. The main carbonation tower and the auxiliary carbonation tower together constitute the ammonium carbonate synthesis tower.

2. The method for carbon neutrality, carbon emission reduction, recycling, and resource recovery according to claim 1, characterized in that, The alkaline scrubbing tower for washing carbon dioxide waste gas specifically includes the following steps: Step 1: Carbon dioxide waste gas enters the alkaline scrubbing tower. When the airflow passes through the blades, it generates rotation and centrifugal motion. The absorbent liquid is evenly distributed to each blade through the middle blind plate, forming a thin liquid layer. Step 2: The blades and the upward rotating airflow create a rotational and centrifugal effect, spraying the liquid into fine droplets that are then flung towards the tower wall; Step 3: The absorbent enters from the top of the tower and exits from the bottom. The airflow and the absorbent move relative to each other inside the tower, forming a water film with a large surface area in the structural part of the cyclone tray. Step 4: The absorbent liquid of each layer falls into the collection tank at the edge through the centrifugal force of the cyclone, and then enters the next tray through the guide pipe to carry out the absorption of the next layer.

3. The method for carbon neutrality, carbon emission reduction, recycling, and resource recovery according to claim 2, characterized in that, In step S4, the generated ammonium bicarbonate solid suspension, including the crystallized suspension, is taken out from the bottom of the ammonium bicarbonate synthesis tower, sent to a thickener, and then flows into a centrifuge for separation, so that the ammonium bicarbonate crystals are separated from the mother liquor, and wet ammonium bicarbonate product is obtained.

4. A carbon neutrality, carbon emission reduction, recycling, and resource recovery system, applicable to the carbon neutrality, carbon emission reduction, recycling, and resource recovery method described in any one of claims 1-3, characterized in that, The system includes an alkaline scrubbing tower, a bag filter, a rotary absorption tower, a compressor, a condenser, and an ammonium carbonate synthesis tower. The alkaline scrubbing tower is used to scrub the carbon dioxide waste gas drawn in by the ventilator. The bag filter removes dust from the scrubbed waste gas. The waste gas after dust removal enters the rotary absorption tower, where it absorbs the carbon dioxide. The absorbed waste liquid is condensed by the condenser, and the unabsorbed waste gas enters the compressor. The compressed waste gas then enters the ammonium carbonate synthesis tower, where the ammonium bicarbonate solid suspension generated is sent to a centrifuge for separation. The separated ammonium bicarbonate solid is dried by a dryer and then collected.

5. A carbon neutrality, carbon emission reduction, recycling, and resource recovery system according to claim 4, characterized in that, The compressor's tail end is connected to the top of both the rotary absorption tower and the ammonium carbonate synthesis tower.

6. The carbon neutrality, carbon emission reduction, recycling, and resource recovery system according to claim 5, characterized in that, The top of the rotary absorption tower is connected to an exhaust chimney, and the ammonium carbonate synthesis tower is connected to a liquid ammonia storage tank.

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