Absorbent for carbon sequestration and decarburization, preparation method thereof and carbon sequestration and decarburization system

Abstract

The invention relates to the technical field of solid waste and hazardous waste treatment, in particular to an absorbent for carbon sequestration and decarburization, a preparation method of the absorbent and a carbon sequestration and decarburization system.The preparation method comprises the steps that S1, hazardous waste raw materials are weighed by mass and subjected to smashing treatment and mixing pretreatment, and a mixed material is formed; s2, conveying the mixed material into a pyrolysis calcining furnace according to a certain treatment amount through a pyrolysis hopper, and performing pyrolysis calcining treatment; s3, the pyrolyzed and calcined material is slowly conveyed into a grinding hopper, meanwhile, the pyrolyzed and calcined material is subjected to spraying and quenching treatment through a spraying and quenching device, then ball milling treatment is conducted, and slurry is obtained; s4, conveying the slurry into a slurry stirring tank, adjusting the pH value of the slurry to be not less than 10, and uniformly stirring to form the absorbent for carbon sequestration and decarburization; when the absorbent for carbon sequestration and decarburization is used for treating carbon dioxide, the treatment cost of solid waste and hazardous waste can be reduced, the utilization value of the solid waste and hazardous waste is increased, and the treatment cost of carbon dioxide can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste and hazardous waste treatment, and in particular to an absorbent for carbon fixation and decarbonization, a preparation method thereof, and a carbon fixation and decarbonization system. Background Art

[0002] Carbon dioxide is one of the main causes of global warming. Capturing, utilizing and storing emitted carbon dioxide is one of the most effective means to achieve large-scale carbon emission reduction and respond to climate change. The existing decarbonization and carbon fixation methods mainly include chemical absorption, physical absorption, physical adsorption, etc. These treatment methods require high investment and consume large amounts of energy. In addition, these methods require the use and consumption of large amounts of decarbonization agents. For example, chemical absorption methods usually use MDEA, MEA, etc. as decarbonization agents, physical absorption methods usually use PC, NHD, methanol, etc. as decarbonization agents, and physical adsorption methods usually use silica gel, etc. as decarbonization agents. This will further increase the cost of decarbonization and carbon fixation. Therefore, it is necessary to find a cheap and widely applicable decarbonization and carbon fixation agent.

[0003] At the current stage of development, industrial hazardous waste (hazardous waste for short) or general solid waste (solid waste for short) is usually backfilled and buried in a specific waste treatment site after a series of strict harmless treatment processes. Although this traditional disposal method can effectively isolate harmful substances to a certain extent and avoid their immediate harm to human society, it requires a large amount of land space resources, which is undoubtedly a heavy burden for today's society with increasingly tight land resources; more seriously, any omissions or leakage caused by long-term natural action during the landfill process may cause harmful substances to penetrate into the soil layer, and then through the circulation of the groundwater system, cause serious pollution to nearby soil, groundwater and other natural elements, and may even spread to a wider area with the flow of air; this pollution not only destroys the balance of the ecological environment, but also seriously threatens the health, safety and quality of life of nearby residents, and brings great challenges to the sustainable development of the natural environment and human society. In order to cope with this problem, researchers and environmental protection departments are constantly exploring more efficient and environmentally friendly solid waste and hazardous waste disposal methods. At present, the conventional treatment methods for hazardous waste and solid waste mainly include solidification treatment method and mineralization treatment method; among them, solidification treatment is to first mix solid waste or hazardous waste with a solidifying agent, so that the solid waste or hazardous waste is contained or fixed in a solidifying substrate, and then converted into ordinary building materials, but the utilization value of this method is relatively single; as for the mineralization treatment method, the implementation methods usually include two types: one is to place the formed solid waste in an acidic gas environment to react and generate carbonates, but this process is not efficient; the other is to use a stirring device to mix the solid waste with an acidic aqueous solution; however, since the stirring device is a mechanical device, the release of acidic gas during operation will cause corrosion to the stirring device; and due to the insufficient sealing performance of the stirring device, the reaction efficiency cannot be improved by pressurization; at the same time, when treating hazardous waste and solid waste in large quantities, the volume of the stirring equipment required is generally large, and the treatment cost also increases accordingly. Therefore, it is necessary to explore a solid waste or hazardous waste treatment method with high treatment efficiency, low cost and high utilization value.

[0004] The present invention provides an absorbent for carbon fixation and decarbonization, a preparation method thereof, and a carbon fixation and decarbonization system to solve the problems existing in the prior art of high treatment cost of solid waste or hazardous waste, single utilization value, high cost of decarbonization and carbon fixation, etc. Summary of the invention

[0005] The purpose of the present invention is to provide an absorbent for carbon fixation and decarbonization, a preparation method thereof, and a carbon fixation and decarbonization system to solve the problems existing in the prior art of high treatment cost of solid waste or hazardous waste, single utilization value, high cost of decarbonization and carbon fixation.

[0006] The technical solution of the present invention is: a method for preparing an absorbent for carbon fixation and decarbonization, comprising the following steps: S1. Weigh hazardous waste materials by mass, and perform crushing treatment and mixing pretreatment on the weighed hazardous waste materials in turn to form a mixed material; the hazardous waste materials include alkaline hazardous waste materials, acidic hazardous waste materials, and hazardous waste materials with uncertain acidity and alkalinity; among the hazardous waste materials, the content of alkaline hazardous waste materials is greater than that of acidic hazardous waste materials; S2, the mixed material is transported to the pyrolysis calciner by the pyrolysis hopper according to a certain amount of disposal, and pyrolysis calcination treatment is carried out in the pyrolysis calciner; the disposal amount does not exceed 2.5t / h; S3, slowly conveying the pyrolysis and calcined material to the grinding hopper, and spraying and quenching the pyrolysis and calcined material through a spray quenching device arranged at the upper end of the grinding hopper, and then conveying the cooled material to a ball mill for ball milling, so that the particle size of the cooled material does not exceed 5mm, and after the ball milling is completed, a slurry is obtained; in the slurry, the mixing ratio of the cooled material to water is 1: (99-98) by weight; S4. The slurry is transported to a slurry stirring tank, and fresh water is transported to the slurry stirring tank. At the same time, the activated composite alkali solution stored in the alkali solution tank is transported to the slurry stirring tank through a dosing pump to adjust the pH value of the slurry to not less than 10. After that, the slurry is stirred evenly to form an absorbent for carbon fixation and decarbonization.

[0007] Preferably, the alkaline hazardous waste material is any one or more of aluminum ash, red mud, fly ash, waste drilling mud, carbide slag, coal gangue, and ironmaking waste slag; the acidic hazardous waste material is any one or more of phosphogypsum slag, acid oil residue, and acid slag; the hazardous waste material with uncertain acidity and alkalinity is any one or more of fly ash, oil sludge, rock cuttings, and garbage; the garbage includes medical waste and domestic waste.

[0008] Preferably, the pyrolysis and calcination treatment uses a burner to ignite natural gas and non-condensable steam, and the high-temperature flue gas generated by the combustion of natural gas and non-condensable steam indirectly heats the mixed material; during the pyrolysis and calcination treatment, the temperature in the pyrolysis and calcination furnace is controlled within the range of 400-1200°C.

[0009] Preferably, the length of the furnace body of the pyrolysis calcining furnace is not less than 20m; the front end of the furnace body of the pyrolysis calcining furnace close to the pyrolysis hopper is a low-temperature pyrolysis zone, and the rear end of the furnace body is a high-temperature calcination zone; The pyrolysis and calcination treatment includes a low-temperature pyrolysis treatment at the front end of the furnace body and a high-temperature calcination treatment at the rear end of the furnace body; the treatment temperature of the low-temperature pyrolysis treatment is 400-480°C.

[0010] Preferably, calculated by mass percentage, the activated composite alkali solution includes 18-23% NaOH, 12-18% piperazine, 8-12% sodium silicate, 10-18% tetraethylenepentamine and the remainder fresh water.

[0011] The present application also provides an absorbent for carbon fixation and decarbonization, which is prepared by the above method.

[0012] The present application also provides a carbon fixation and decarbonization system, which includes a carbon dioxide absorption device connected to the output end of a flue gas delivery pump arranged on a flue gas delivery pipeline or connected to a carbon dioxide aqueous solution tank, wherein the carbon dioxide absorption device is connected to the slurry stirring tank containing the absorbent for carbon fixation and decarbonization.

[0013] Preferably, when the carbon dioxide absorption device is connected to the carbon dioxide aqueous solution tank, the carbon dioxide absorption device includes a pipeline mixer, a solid-liquid separator, a steam-water separator, and a screw conveyor connected to the carbon dioxide aqueous solution tank at the front end; The front end of the pipeline mixer is also connected to the slurry stirring tank through a slurry pump; the rear end of the pipeline mixer is connected to the solid-liquid separator; the upper end of the solid-liquid separator is connected to the steam-water separator, and the bottom is connected to the screw conveyor; the upper end of the steam-water separator is provided with a gas outlet, and the bottom is provided with a liquid outlet.

[0014] Preferably, when the carbon dioxide absorption device is connected to the carbon dioxide aqueous solution tank, the carbon dioxide absorption device includes a solid-liquid separation cyclone connected to the slurry stirring tank through a slurry pump, a high-alkalinity solid material hopper connected to the bottom of the solid-liquid separation cyclone, and a double-axis screw high-pressure reactor connected to the high-alkalinity solid material hopper; the double-axis screw high-pressure reactor is horizontally arranged; the front end of the double-axis screw high-pressure reactor is connected to the carbon dioxide aqueous solution tank through a pipeline; the rear end of the double-axis screw high-pressure reactor is provided with an exhaust port and a discharge port.

[0015] Preferably, when the carbon dioxide absorption device is connected to the output end of the flue gas conveying pump arranged on the flue gas conveying pipeline, the carbon dioxide absorption device includes a desulfurization and decarbonization tower; the bottom end of the desulfurization and decarbonization tower is connected to the output end of the flue gas conveying pump arranged on the flue gas conveying pipeline, and the upper end is connected to the slurry stirring tank through a slurry pump; the top of the desulfurization and decarbonization tower is provided with a gas exhaust outlet, and the bottom is provided with a solid outlet.

[0016] Compared with the prior art, the advantages of the present invention are: The present invention provides an absorbent for carbon fixation and decarbonization, a preparation method thereof, and a carbon fixation and decarbonization system. Solid waste or hazardous waste is prepared into the absorbent for carbon fixation and decarbonization through mixing, pyrolysis, incineration, grinding and other treatments, and is used to treat carbon dioxide in the decarbonization and carbon fixation system. This can not only reduce the treatment cost of solid waste and hazardous waste, and increase the utilization value of solid waste and hazardous waste, but also improve the efficiency of carbon dioxide absorption through a pipeline reaction system and an extended pipeline, thereby reducing the cost of carbon dioxide disposal. This solves the problems of high treatment cost of solid waste or hazardous waste, single utilization value, high decarbonization and carbon fixation costs, and the like in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is a schematic structural diagram of the carbon fixation and decarbonization system of the present invention; Among them: 1. pyrolysis hopper, 2. pyrolysis calcining furnace; 3. burner; 4. grinding hopper; 5. ball mill; 6. spray quenching device; 7. desulfurization and decarbonization tower; 71. flue gas conveying pump; 8. alkali liquid tank; 81. dosing pump; 9. slurry stirring tank; 91. slurry pump; 10. solid-liquid separation cyclone; 11. high alkaline solid material hopper; 12. carbon dioxide aqueous solution tank; 13. double-axis screw high-pressure reactor; 14. solid-liquid separator; 15. pipeline mixer; 16. steam-water separator; 17. carbon dioxide recovery compressor; 18. screw conveyor. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below in conjunction with specific embodiments: The present application provides an absorbent for carbon fixation and decarbonization, which uses hazardous waste or solid waste as raw materials, and through mixing, pyrolysis, incineration, grinding and other treatments, the hazardous waste or solid waste raw materials are subjected to a series of physical and chemical reactions to form an excited state of highly alkaline solid slurry, and is used as an absorbent for decarbonization and carbon fixation. Among them, pyrolysis is to promote the thermal cracking of organic components in the waste through a high temperature environment, and convert them into gas, liquid and solid residues; incineration is to completely burn the waste under high temperature conditions to generate ash and flue gas, and the main substances that finally generate ash include relatively stable compounds such as metal oxides and silicates; and these metal oxides and silicates, when in contact with water, can react chemically to form alkaline substances or hydrolyze to produce alkaline substances. Therefore, this characteristic of hazardous waste or solid waste provides the possibility for the subsequent resource utilization of waste; it can achieve the recycling of waste while reducing environmental pollution, and promote the harmonious development of economy and environment.

[0019] The present application also provides a method for preparing the above-mentioned absorbent for carbon fixation and decarbonization, and the preparation method specifically comprises the following steps: S1. Weigh hazardous waste raw materials by mass, and perform crushing treatment and mixing pretreatment on the weighed hazardous waste raw materials in turn to form a mixed material; wherein, the hazardous waste raw materials include any one of alkaline hazardous waste materials, acidic hazardous waste materials, and hazardous waste materials with uncertain acidity and alkalinity, or a combination of more than one; when the hazardous waste raw materials include both alkaline hazardous waste materials and acidic hazardous waste materials or include both alkaline hazardous waste materials, acidic hazardous waste materials, and hazardous waste materials with uncertain acidity and alkalinity, the content of alkaline hazardous waste materials is much greater than that of acidic hazardous waste materials; and when the hazardous waste raw materials are acidic hazardous waste materials or liquids, lime or alkaline substances are required to adjust their pH value. Commonly used alkaline hazardous waste materials include aluminum ash, red mud, fly ash, waste drilling mud, carbide slag, coal gangue, iron smelting waste slag, etc.; commonly used acidic hazardous waste materials include phosphogypsum slag, acid oil slag, acid slag, etc.; commonly used hazardous waste materials with uncertain acidity and alkalinity include fly ash, oil sludge, rock cuttings, and garbage; among them, the main components of fly ash include silicon dioxide, aluminum oxide, iron oxide, calcium oxide, etc., and its acidity and alkalinity depend on its chemical composition and mineral composition. When the content of silicate (such as silicon dioxide) and aluminate (such as aluminum dioxide) in fly ash is high, the fly ash is acidic; and when the content of calcium hydroxide (lime) in fly ash is high, the fly ash is alkaline. ; In the present application, both acidic fly ash and alkaline fly ash can be used as hazardous waste materials in the preparation of absorbents for carbon fixation and decarbonization; the acidity and alkalinity of rock cuttings depends on their composition and source, and both acidic and alkaline rock cuttings can be used as hazardous waste materials for the present application, preferably alkaline rock cuttings; the garbage used in the present application includes medical waste and domestic waste; the acidity and alkalinity of medical waste and domestic waste also depend on their main components; in the process of preparing absorbents for carbon fixation and decarbonization, adding garbage can increase the calorific value of solid waste and hazardous waste; increase the non-condensable steam generated in the pyrolysis process, and circulate the non-condensable steam for combustion, which plays a role in reducing natural gas consumption. The weighed solid hazardous waste raw materials need to be crushed first, so that the particle size of the hazardous waste raw materials is controlled within the range of 2-3cm, and then the crushed hazardous waste raw materials are added to a mixing container together with other hazardous waste raw materials for mixing pretreatment, and mixed evenly to form a mixed material.

[0020] S2, transporting the mixed material to the pyrolysis calcining furnace 2 according to a certain disposal amount through the pyrolysis hopper 1, and performing pyrolysis calcination treatment in the pyrolysis calcining furnace 2; wherein the disposal amount does not exceed 2.5 tons / hour (t / h); and, if Figure 1As shown, the pyrolysis calcining furnace 2 horizontally penetrates the combustion device, and the burner 3 is arranged at the bottom of the combustion device; the pyrolysis calcining treatment adopts the burner 3 to ignite the natural gas and non-condensable steam in the combustion device, and the high-temperature flue gas generated by the combustion of the natural gas and non-condensable steam indirectly heats the mixed material; during the pyrolysis calcining treatment process, according to the different hazardous waste raw materials used, the temperature in the pyrolysis calcining furnace 2 needs to be controlled in the range of 400-1200℃. In the present application, a pyrolysis calcining furnace 2 with a furnace body length of not less than 20m is usually selected, and the diameter of the pyrolysis calcining furnace 2 is proportional to the processing capacity. For example, when the processing capacity is 1t / h, a pyrolysis calcining furnace 2 with a furnace body diameter of 1m is selected, and when the processing capacity is 1.5t / h, a pyrolysis calcining furnace 2 with a furnace body diameter of 1.5m is selected; the front end of the furnace body of the pyrolysis calcining furnace 2 close to the pyrolysis hopper 1 is a low-temperature pyrolysis zone, and the furnace body length of the low-temperature pyrolysis zone is 8-12m, and the rear end of the furnace body is a high-temperature calcination zone; the mixed material transported to the pyrolysis calcining furnace 2 is first subjected to low-temperature pyrolysis treatment at the front end of the furnace body, and the processing temperature of the low-temperature pyrolysis treatment is 400-480℃; and then transported from the front end of the furnace body to the rear end of the furnace body for high-temperature calcination treatment. The organic materials in the mixture will decompose to produce combustible non-condensable gases after high-temperature calcination. These non-condensable gases circulate and burn in the combustion device, which can effectively reduce the use of natural gas and save the cost of mixed material disposal. The inorganic materials in the mixture will decompose or form silicates with the silicon dioxide therein after high-temperature calcination.

[0021] S3, slowly conveying the pyrolysis calcined material to the grinding hopper 4, and spraying and quenching the pyrolysis calcined material through the spray quenching device 6 arranged at the upper end of the grinding hopper 4, and then conveying the cooled material to the ball mill 5 for ball milling, so that the particle size of the cooled material does not exceed 5mm, and after the ball milling is completed, a slurry is obtained; wherein the length of the ball mill 5 is about 5m; the diameter of the ball mill 5 is proportional to its disposal capacity, for example, when the disposal capacity of the ball mill 5 is 1t / h, a ball mill with a diameter of 1m is selected, and when the disposal capacity of the ball mill 5 is When the speed is 2t / h, a ball mill with a diameter of 2m is selected; the processing capacity of the ball mill 5 does not exceed 2.51t / h; through the continuous rotation of the ball mill 5, the steel balls in the ball mill 5 continuously grind the cooled material, so that the particle size of the cooled material reaches below 5mm, and the small particle material can increase its contact area with carbon dioxide gas or carbon dioxide aqueous solution, thereby increasing its reaction rate with carbon dioxide gas or carbon dioxide aqueous solution; at the same time, in order to ensure that the slurry has good fluidity, the mixing ratio of solid material to water is 1:99-98 calculated by weight.

[0022] S4, conveying the slurry to the slurry stirring tank 9, and conveying fresh water to the slurry stirring tank 9, at the same time, conveying the activated composite alkali solution stored in the alkali solution tank 8 to the slurry stirring tank 9 through the dosing pump 81 to adjust the pH value of the slurry, and then stirring evenly to obtain an absorbent for carbon fixation and decarbonization. After the ground slurry is conveyed to the slurry stirring tank 9, it is necessary to first test the pH value of the slurry. When the pH value of the slurry is not less than 10, it is not necessary to convey the activated composite alkali solution to the slurry stirring tank 9. Only when it is found that the pH value of the slurry is less than 10, it is necessary to convey the activated composite alkali solution stored in the alkali solution tank 8 to the slurry stirring tank 9 through the dosing pump 81 to adjust the pH value of the slurry and use it to activate the slurry; wherein, calculated by mass percentage, the activated composite alkali solution includes 18-23% of N aOH, 12-18% piperazine (PZ), 8-12% sodium silicate, 10-18% tetraethylene pentamine and the rest of fresh water; further, the preferred activated composite alkali solution includes 20% NaOH, 15% piperazine, 10% sodium silicate, and 15% tetraethylene pentamine; the role of NaOH is mainly to increase the pH value of the slurry, the role of piperazine is mainly to cooperate with tetraethylene pentamine to absorb carbon dioxide, and the role of sodium silicate is mainly to cooperate with NaOH to activate silicate and promote the crystallization and solidification of silicate. When preparing the absorbent for carbon fixation and decarbonization, high alkalinity hazardous waste raw materials should be added as much as possible to ensure or increase the alkalinity of the slurry and reduce the amount of activated composite alkali solution used.

[0023] The present application also provides a carbon fixation and decarbonization system; the carbon fixation and decarbonization system includes a carbon dioxide absorption device connected to the output end of the flue gas delivery pump 71 arranged on the flue gas delivery pipeline or to the carbon dioxide aqueous solution tank 12; the carbon dioxide absorption device is also connected to the slurry stirring tank 9 containing the absorbent for carbon fixation and decarbonization. Among them, the input end of the flue gas delivery pump 71 arranged on the flue gas delivery pipeline is connected to the device for generating or storing flue gas, which is used to transport the flue gas to the desulfurization and decarbonization tower 7 to contact and react with the absorbent for decarbonization and carbon fixation; and the carbon dioxide aqueous solution tank 12 is connected to the carbon dioxide recovery compression unit and the fresh water source through the air flow pipeline and the water flow pipeline respectively; the carbon dioxide gas recovered from other ways is transported to the carbon dioxide aqueous solution tank 12 after being processed by the carbon dioxide recovery compression unit, and is dissolved in the fresh water transported to the carbon dioxide aqueous solution tank to form a carbon dioxide aqueous solution.

[0024] Among them, when the carbon dioxide absorption device is connected to the output end of the flue gas delivery pump 71 arranged on the flue gas delivery pipeline, the carbon dioxide absorption device includes a desulfurization and decarbonization tower 7; the bottom end of the desulfurization and decarbonization tower 7 is connected to the output end of the flue gas delivery pump 71 arranged on the flue gas delivery pipeline, and the upper end of the desulfurization and decarbonization tower 7 is connected to the slurry stirring tank 9 through a slurry pump 91; the top of the desulfurization and decarbonization tower 7 is provided with a gas outlet, and the gas outlet is connected to the desulfurization and decarbonization seawater emptying area through a pipeline, and the bottom of the desulfurization and decarbonization tower 7 is provided with a solid outlet, and the solid outlet is connected to the sulfur-fixing and carbon-fixing slurry storage area through a pipeline. At this time, the carbon-fixing and decarbonization system is equivalent to a traditional tower system, and the decarbonization and carbon-fixing absorbent is directly transported to the desulfurization and decarbonization tower through a slurry pump, and is contacted with the flue gas spray, so that the acidic gases such as sulfur dioxide and carbon dioxide in the flue gas react with the highly alkaline decarbonization and carbon-fixing absorbent, and the reaction process is similar to the traditional lime milk desulfurization.

[0025] When the carbon dioxide absorption device is connected to the carbon dioxide aqueous solution tank 12, the carbon dioxide absorption device includes a solid-liquid separation cyclone 10 connected to the slurry stirring tank 9 through a slurry pump 91, a high-alkalinity solid material hopper 11 connected to the bottom of the solid-liquid separation cyclone 10, and a double-axis spiral high-pressure reactor 13 connected to the high-alkalinity solid material hopper 11; and the double-axis spiral high-pressure reactor 13 is horizontally arranged; the front end of the double-axis spiral high-pressure reactor 13 is connected to the carbon dioxide aqueous solution tank 12 through a pipeline; the rear end of the double-axis spiral high-pressure reactor 13 is provided with an exhaust port and a discharge port. At this time, the carbon fixation and decarbonization system is a double-axis spiral high-pressure reaction system. The absorbent for decarbonization and carbon fixation is transported to the solid-liquid separation cyclone 10 through the slurry pump 91. Solid and liquid separation is performed in the solid-liquid separation cyclone 10. The highly alkaline solid material with a particle size of less than 5 microns obtained by separation and concentration is discharged from the bottom of the solid-liquid separation cyclone 10 and transported to the double-axis spiral high-pressure reactor 13. At the same time, the carbon dioxide aqueous solution stored in the carbon dioxide aqueous solution tank 12 and dissolved in water at a high pressure of 1MPa will be transported to the double-axis spiral high-pressure reactor 13, and fully mixed and mineralized with the highly alkaline solid material in the double-axis spiral high-pressure reactor 13. The product of the mineralization reaction and the liquid are transported out from the discharge port at the rear end of the double-axis spiral high-pressure reactor 13 for disposal or made into carbon fixation building materials, and the unreacted carbon dioxide gas is recovered to the carbon dioxide aqueous solution tank 12. Further, valves are provided at the feed point at the front end and the discharge point at the rear end of the double-axis spiral high-pressure reactor 13 to close the device.

[0026] In order to improve the reaction efficiency, it is necessary to control the opening of the valve at the exhaust port of the double-axis spiral high-pressure reactor, maintain the pressure in the double-axis spiral high-pressure reactor, and ensure that the carbon dioxide is always in a dissolved state. The carbon fixation and decarbonization system mainly uses the alkalinity of solid waste and hazardous waste for decarbonization. The higher the alkalinity, the better the decarbonization effect. The collected and purified carbon dioxide can also be used for carbon fixation with hazardous waste and solid waste. The solid waste after carbon fixation can be made into green carbon fixation building materials.

[0027] In addition, in order to improve the efficiency of the reaction and absorption of the absorbent for carbon fixation and decarbonization with carbon dioxide and reduce the cost of carbon dioxide disposal, the present application also provides a pipeline reaction system for carbon fixation and decarbonization; that is, when the carbon dioxide absorption device is connected to the carbon dioxide aqueous solution tank 12, the carbon dioxide absorption device can also include a pipeline mixer 15, a solid-liquid separator 14, a gas-water separator 16 and a screw conveyor 18 connected to the front end of the carbon dioxide aqueous solution tank 12; and the front end of the pipeline mixer 15 is also connected to the slurry stirring tank 9 through a slurry pump 91, which is used to transport the absorbent for carbon fixation and decarbonization to the pipeline mixer 15 at a pressure of 1 MPa, and mix it with the carbon dioxide aqueous solution in the pipeline mixer 15, so that the carbon dioxide gas in the carbon dioxide aqueous solution reacts and is absorbed with the absorbent for carbon fixation and decarbonization; at the same time, the contact time between carbon dioxide and the slurry can be extended by extending the length of the pipeline, thereby improving the reaction efficiency; the pipeline has a lower cost and is more convenient to process, which also helps to reduce the cost of decarbonization and carbon fixation. The rear end of the pipeline mixer 15 is connected to the solid-liquid separator 14, which is used to transport the product of the reaction of the carbon fixation and decarbonization absorbent with carbon dioxide, the carbon fixation and decarbonization absorbent that has not participated in the reaction, and the unreacted carbon dioxide aqueous solution to the solid-liquid separator 14, and complete the separation in the solid-liquid separator 14; the upper end of the solid-liquid separator 14 is connected to the steam-water separator 16, which is used to transport the separated carbon dioxide aqueous solution to the steam-water separator 16 for separation of the water phase and the gas phase; the upper end of the steam-water separator 16 is provided with a gas outlet, which is used to discharge the separated gas phase into the atmosphere or to be recovered into the carbon dioxide aqueous solution tank through the carbon dioxide recovery compressor 17, and the bottom of the steam-water separator is provided with a liquid outlet, which is used to discharge the separated water phase and return it to the slurry stirring tank 9 for continued use or return it to the ball mill for continued use in slurry making; the bottom of the solid-liquid separator 14 is connected to the screw conveyor, which is used to transport the separated solid to the screw conveyor 18, and discharge it through the screw conveyor 18 for backfilling or making it into carbon fixation building materials.

[0028] The following lists five combinations of hazardous waste raw materials with different components and proportions, which are prepared into absorbents for carbon fixation and decarbonization through the above-mentioned preparation method; in the hazardous waste raw material combination, the proportion of each component is calculated by mass; the specific combination and proportion of hazardous waste raw materials are shown in Table 1.

[0029] Table 1. Combinations of hazardous waste materials with different components and ratios Components Fly ash Aluminum ash Red Mud Drilling Mud Cuttings Contains sludge Phosphogypsum Rubbish Acidity and alkalinity Alkaline Alkaline Alkaline Alkaline uncertain uncertain Acidic uncertain Combination 1 1 1 1 1 1 1 1 10 Combination 2 / / 1 1 1 5 1 5 Combination 3 1 1 / 1 1 5 1 2 Combination 4 1 1 1 1 1 / 1 8 Combination 5 1 1 5 / / / 1 8 The five groups of absorbents for carbon fixation and decarbonization prepared by using different components and proportions of hazardous waste raw materials were applied to the above-mentioned traditional tower for carbon fixation and decarbonization; the absorption rate of flue gas and acid gas in the absorption tower was designed to be 95%. The flow rate value of the absorbent for carbon fixation and decarbonization consumed to achieve this absorption rate is shown in Table 2.

[0030] combination Combination 1 Combination 1 Combination 2 Combination 2 Combination 5 Combination 5 pH 11 13 11 13 11 13 Designed absorption tower flue gas acid gas absorption rate 95% <![CDATA[1Nm 3 Smoke / 18.2m 3 Slurry]]> <![CDATA[10Nm 3 Smoke / 13.5m 3 Slurry]]> <![CDATA[1Nm 3 Smoke / 17.9m 3 Slurry]]> <![CDATA[1Nm 3 Smoke / 14.4m 3 Slurry]]> <![CDATA[1Nm 3 Smoke / 11.2m 3 Slurry]]> <![CDATA[1Nm 3 Smoke / 9.1m 3 Slurry]]> It can be seen from Table 2 that the higher the pH value of the absorbent used for carbon fixation and decarbonization, the more helpful it is for the absorption of acidic gases such as carbon dioxide; in the combination of hazardous waste raw materials, increasing the proportion of red mud is also helpful for the absorption of acidic gases such as carbon dioxide.

[0031] The pH values ​​of the five kinds of absorbents for carbon fixation and decarbonization prepared by the five groups of hazardous waste raw materials with different components and proportions were adjusted to 11. Then, the five kinds of absorbents for carbon fixation and decarbonization were respectively applied to the above-mentioned double-axis spiral high-pressure reaction system, pipeline reaction system and traditional mechanical stirring reaction system, and the carbon dioxide aqueous solution was treated under the same parameter conditions. The average escape rate of carbon dioxide in the treatment process of the carbon dioxide aqueous solution in different reaction systems was detected. The specific test results are shown in Table 3.

[0032] Table 3. Average carbon dioxide escape rate of the same reaction system System Name Double-axis spiral high pressure reaction system Traditional mechanical stirring reaction system Pipeline reaction system Average CO2 Escape Rate 64% 91% 34.5% It can be seen from Table 3 that when a pipeline reaction system is used and five kinds of absorbents for carbon fixation and decarbonization are used to treat carbon dioxide aqueous solution, the average carbon dioxide escape rate is 34.5%, which is significantly lower than the average carbon dioxide escape rate when a double-axis spiral high-pressure reaction system and a traditional mechanical stirring reaction system are used. This further shows that the use of a pipeline reaction system can significantly improve the efficiency of the reaction and absorption of the absorbent for carbon fixation and decarbonization with carbon dioxide and reduce the cost of carbon dioxide disposal.

[0033] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the scope of protection of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A method for preparing an absorbent for carbon fixation and decarbonization, characterized in that: The following steps are involved: S1. Weigh hazardous waste materials by mass, and perform crushing treatment and mixing pretreatment on the weighed hazardous waste materials in turn to form a mixed material; the hazardous waste materials include alkaline hazardous waste materials, acidic hazardous waste materials, and hazardous waste materials with uncertain acidity and alkalinity; among the hazardous waste materials, the content of alkaline hazardous waste materials is greater than that of acidic hazardous waste materials; S2, the mixed material is transported to the pyrolysis calciner by the pyrolysis hopper according to a certain amount of disposal, and pyrolysis calcination treatment is carried out in the pyrolysis calciner; the disposal amount does not exceed 2.5t / h; S3, slowly conveying the pyrolysis and calcined material to the grinding hopper, and spraying and quenching the pyrolysis and calcined material through a spray quenching device arranged at the upper end of the grinding hopper, and then conveying the cooled material to a ball mill for ball milling, so that the particle size of the cooled material does not exceed 5mm, and after the ball milling is completed, a slurry is obtained; in the slurry, the mixing ratio of the cooled material to water is 1: (99-98) by weight; S4. The slurry is transported to a slurry stirring tank, and fresh water is transported to the slurry stirring tank. At the same time, the activated composite alkali solution stored in the alkali solution tank is transported to the slurry stirring tank through a dosing pump to adjust the pH value of the slurry to not less than 10. After that, the slurry is stirred evenly to form an absorbent for carbon fixation and decarbonization.

2. The method for preparing an absorbent for carbon fixation and decarbonization according to claim 1, characterized in that: The alkaline hazardous waste materials are any one or more of aluminum ash, red mud, fly ash, waste drilling mud, carbide slag, coal gangue, and ironmaking waste slag; the acidic hazardous waste materials are any one or more of phosphogypsum slag, acid oil slag, and acid slag; the hazardous waste materials with uncertain acidity and alkalinity are any one or more of fly ash, oil sludge, rock cuttings, and garbage; the garbage includes medical waste and domestic waste.

3. The method for preparing an absorbent for carbon fixation and decarbonization according to claim 2, characterized in that: The pyrolysis calcination treatment uses a burner to ignite natural gas and non-condensable steam, and the high-temperature flue gas generated by the combustion of natural gas and non-condensable steam indirectly heats the mixed material; during the pyrolysis calcination treatment process, the temperature in the pyrolysis calcination furnace is controlled within the range of 400-1200°C.

4. The method for preparing an absorbent for carbon fixation and decarbonization according to claim 3, characterized in that: The length of the furnace body of the pyrolysis calcining furnace is not less than 20m; the front end of the furnace body of the pyrolysis calcining furnace close to the pyrolysis hopper is a low-temperature pyrolysis zone, and the rear end of the furnace body is a high-temperature calcination zone; The pyrolysis and calcination treatment includes a low-temperature pyrolysis treatment at the front end of the furnace body and a high-temperature calcination treatment at the rear end of the furnace body; the treatment temperature of the low-temperature pyrolysis treatment is 400-480°C.

5. The method for preparing an absorbent for carbon fixation and decarbonization according to claim 1, characterized in that: Calculated by mass percentage, the activated composite alkali solution includes 18-23% NaOH, 12-18% piperazine, 8-12% sodium silicate, 10-18% tetraethylenepentamine and the rest fresh water.

6. An absorbent for carbon fixation and decarbonization, characterized in that: The preparation method is described in any one of claims 1 to 5.

7. A carbon fixation and decarbonization system, comprising a carbon dioxide absorption device connected to the output end of a flue gas delivery pump arranged on a flue gas delivery pipeline or connected to a carbon dioxide aqueous solution tank, characterized in that: The carbon dioxide absorption device is connected to the slurry stirring tank described in any one of claims 1-5.

8. A carbon fixation and decarbonization system according to claim 7, characterized in that: When the carbon dioxide absorption device is connected to the carbon dioxide aqueous solution tank, the carbon dioxide absorption device includes a pipeline mixer, a solid-liquid separator, a steam-water separator, and a screw conveyor whose front end is connected to the carbon dioxide aqueous solution tank; The front end of the pipeline mixer is also connected to the slurry stirring tank through a slurry pump; the rear end of the pipeline mixer is connected to the solid-liquid separator; the upper end of the solid-liquid separator is connected to the steam-water separator, and the bottom is connected to the screw conveyor; the upper end of the steam-water separator is provided with a gas outlet, and the bottom is provided with a liquid outlet.

9. A carbon fixation and decarbonization system according to claim 7, characterized in that: When the carbon dioxide absorption device is connected to the carbon dioxide aqueous solution tank, the carbon dioxide absorption device includes a solid-liquid separation cyclone connected to the slurry stirring tank through a slurry pump, a high-alkalinity solid material hopper connected to the bottom of the solid-liquid separation cyclone, and a double-axis spiral high-pressure reactor connected to the high-alkalinity solid material hopper; the double-axis spiral high-pressure reactor is horizontally arranged; the front end of the double-axis spiral high-pressure reactor is connected to the carbon dioxide aqueous solution tank through a pipeline; the rear end of the double-axis spiral high-pressure reactor is provided with an exhaust port and a discharge port.

10. A carbon fixation and decarbonization system according to claim 7, characterized in that: When the carbon dioxide absorption device is connected to the output end of the flue gas conveying pump arranged on the flue gas conveying pipeline, the carbon dioxide absorption device includes a desulfurization and decarbonization tower; the bottom end of the desulfurization and decarbonization tower is connected to the output end of the flue gas conveying pump arranged on the flue gas conveying pipeline, and the upper end is connected to the slurry stirring tank through a slurry pump; the top of the desulfurization and decarbonization tower is provided with a gas exhaust outlet, and the bottom is provided with a solid outlet.

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