A calcium source solid waste leaching-absorption-carbonation reaction circulating system and method based on biomineralization

Abstract

The application discloses a calcium source solid waste leaching-absorption-carbonation reaction circulating system and method based on biological mineralization, and belongs to the technical field of calcium source solid waste treatment and CO2 solidification. The system and method disclosed by the application adopt a CO2 absorption system, a calcium source solid waste leaching system and a carbonation reaction system, adopt a composite absorbent to respectively realize CO2-containing flue gas absorption and calcium source solid waste leaching, and connect a liquid product collecting system with the CO2 absorption system and the calcium source solid waste leaching system respectively, so that the composite absorbent can be recycled, wherein the composite absorbent serves as both a leaching agent of the calcium source solid waste and a low-concentration CO2 gas absorbent, and respectively completes the leaching and absorption processes independently, the carbonation reaction is a liquid-liquid reaction, and the disadvantages of low gas-liquid interface mass transfer rate and uneven bubble particle size in the bubbling carbonation reaction mode, which result in CO2 bubble dissolution difference and affect product characteristic change, are avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of calcium source solid waste treatment and CO2 solidification, and specifically relates to a calcium source solid waste leaching-absorption-carbonation reaction cycle system and method based on biomineralization. Background Art

[0002] Due to the high carbon emissions from coal-fired power generation and heating, the CO2 concentration in the flue gas emitted is generally low and carries fine dust. Under the goal of carbon neutrality, the task of reducing carbon emissions from coal-fired boilers will be very challenging. Currently, chemical absorption is one of the most promising carbon capture technologies. It uses ethanolamine (MEA) or complex alcoholamine solutions with a relatively fast absorption rate to absorb CO2, and then regenerates it through high-temperature decomposition of carbamate or chemical regeneration by adding low-cost calcium source solid waste. However, these adsorbent regeneration processes have problems such as high regeneration energy consumption, low gas-solid interface reaction rates, dissolution and accumulation of other ions, and limited utilization value of mineralized products (carbonate-attached solid waste).

[0003] Fly ash is the source of calcium in fly ash produced by pulverized coal boilers in power plants. The calcium element mainly exists in the form of aluminosilicate minerals such as CaSO4, Ca2SiO4 and anorthite. The particle size is generally small and it is in urgent need of reduction, harmlessness and resource utilization. Amino acids can release H + Neutralize CaO and Ca(OH)2 in ash, which is beneficial to the Ca in calcium compounds 2+ However, the CO2 absorption load of amino acids is one order of magnitude lower than that of single or compound alcoholamine solutions, so they are not suitable as CO2 absorbents alone.

[0004] In order to reduce carbon and recycle calcium source solid waste, the Chinese patent application with publication number CN116099347A proposed a system and method for preparing light calcium carbonate by CO2 cycle absorption-mineralization. The calcium-based alkaline solid waste leachate prepared in advance is mixed with the CO2 absorbent lean solution to achieve absorption-mineralization integration in the reaction vessel. However, its bubbling mineralization reaction mode has the problems of low gas-liquid interface mass transfer rate and uneven bubble particle size, which can easily lead to differences in CO2 bubble dissolution and affect product characteristics, resulting in low economic benefits. In addition, the calcium source solid waste leaching agent and the CO2 absorbent are not the same solvent and need to be configured and adjusted separately, which increases the system devices and steps. The Chinese patent application with publication number CN115820946A proposed a method for comprehensive utilization of steel slag, using NH4Cl solution as the leaching agent, which is divided into primary and secondary leaching reactions. The reaction is relatively thorough, but the Cl - It will cause corrosion to the reaction vessels, reduce the service life of the system, and pollute the environment, making it difficult to further process and recycle. In addition, the temperature of the primary reaction system is 5-55°C and the temperature of the secondary reaction system is 90-125°C, which increases the energy consumption. Summary of the Invention

[0005] The present application aims to provide a calcium source solid waste leaching-absorption-carbonation reaction cycle system and method based on biomineralization, which is used to solve the low gas-liquid interface mass transfer rate in the existing bubbling carbonation reaction mode and the low gas-solid interface reaction rate in the absorption agent regeneration process.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The present application discloses a calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization, which comprises a CO2 absorption system, a calcium source solid waste leaching system and a carbonation reaction system; the CO2 absorption system and the calcium source solid waste leaching system are connected with the carbonation reaction system respectively; the carbonation reaction system further comprises a solid product collection system and a liquid product collection system;

[0008] The composite absorbent is placed in the CO2 absorption system and the calcium source solid waste leaching system, which is used to realize the absorption of CO2-containing flue gas and the leaching of calcium source solid waste respectively;

[0009] The liquid product collection system is connected with the CO2 absorption system and the calcium source solid waste leaching system respectively, which is used to realize the recycling of the composite absorbent.

[0010] Further, the CO2 absorption system comprises a washing tower, a separator, a first-stage CO2 absorption device, a second-stage CO2 absorption device, a CO2 composite absorbent supply device and a CO2 absorption post-storage tank;

[0011] The inlet end of the washing tower of the CO2 absorption system is connected with a CO2 flue gas source, and the outlet end is connected with the inlet end of the separator; the liquid outlet end of the separator is connected with the top of the washing tower; the gas outlet end of the separator is connected with the inlet end of the first-stage CO2 absorption device; the outlet end of the first-stage CO2 absorption device is connected with the inlet end of the second-stage CO2 absorption device; the outlet end of the second-stage CO2 absorption device is connected with the inlet end of the CO2 absorption post-storage tank; and the outlet end of the CO2 absorption post-storage tank is connected with the calcium source solid waste leaching system;

[0012] The CO2 composite absorbent supply device is communicated with the bottom of the first-stage CO2 absorption device and the second-stage CO2 absorption device respectively;

[0013] The top of the second-stage CO2 absorption device is further connected with a residual gas air discharge device; and a first water pump is further arranged between the outlet end of the CO2 absorption post-storage tank and the calcium source solid waste leaching system.

[0014] Further, the calcium source solid waste leaching system comprises a leaching Ca 2+ device, a leaching Ca2+ Composite absorbent supply device and Ca 2+ Liquid storage tank after leaching; the leaching Ca 2+ The inlet end of the device is connected to the calcium source solid waste source; the leaching Ca 2+ The outlet of the device and Ca 2+ After leaching, the inlet end of the liquid storage tank is connected; the Ca 2+ The outlet end of the liquid storage tank after leaching is connected to the calcium source solid waste leaching system;

[0015] The leaching of Ca 2+ Composite absorbent supply device and leaching Ca 2+ The bottom of the device is connected;

[0016] The leaching of Ca 2+ The bottom of the device is also connected to an ultrasonic device; the Ca 2+ A second water pump is also connected between the outlet end of the post-leaching liquid storage tank and the calcium source solid waste leaching system.

[0017] Furthermore, the carbonation reaction system comprises a carbonation reaction device, a solid product collection system and a liquid product collection system; the outlet end of the CO2 absorption liquid storage tank, the Ca 2+ The outlet ends of the post-leaching liquid storage tanks are respectively connected to the inlet ends of the carbonation reaction device; and the outlet ends of the carbonation reaction device are respectively connected to a solid product collection system and a liquid product collection system.

[0018] Furthermore, the solid product collection system includes a solid product collection tank and a drying box; the liquid product collection system includes a liquid product standing tank and a liquid storage tank; the outlet end of the carbonation reaction device is connected to the inlet end of the solid product collection tank; the outlet end of the solid product collection tank is connected to the drying box; the outlet end of the carbonation reaction device is connected to the inlet end of the liquid product standing tank; the solid product outlet end of the liquid product standing tank is connected to the inlet end of the solid product collection tank; and the liquid product outlet end of the standing tank is connected to the liquid storage tank.

[0019] Furthermore, the liquid storage tank is respectively connected to the CO2 composite absorbent supply device and the Ca leaching device. 2+ The composite absorbent supply device is connected; the CO2 composite absorbent supply device and the leaching Ca 2+ Composite absorbent supply devices are all equipped with composite absorbents to achieve the absorption of CO2 flue gas and the leaching of calcium source solid waste.

[0020] The present invention also discloses a calcium source solid waste leaching-absorption-carbonation reaction cycle method based on biomineralization, comprising the following steps:

[0021] Prepare a composite absorbent of a composite alcoholamine-amino acid-water system and allocate the amount of the composite absorbent in the CO2 absorption system and the calcium source solid waste leaching system;

[0022] The CO2 flue gas is introduced into the CO2 absorption system and the composite absorbent is used to absorb the CO2 to obtain a CO2-rich absorbent;

[0023] Calcium source solid waste is added into the calcium source solid waste leaching system and composite absorbent is used to make it Ca 2+ Leaching and dissolution to obtain Ca-rich 2+ absorbent;

[0024] The CO2-rich absorbent and the Ca-rich 2+ The absorbent is placed in a carbonation reaction system to carry out a carbonation reaction, and after the reaction is completed, the obtained reaction solution is filtered to obtain a solid product and a liquid product;

[0025] The solid product is collected through a solid product collection system, and the liquid product is placed in a liquid product collection system, and then added to a CO2 absorption system and a calcium source solid waste leaching system respectively to realize the recycling of the composite absorbent.

[0026] Furthermore, the composite absorbent of the composite alcoholamine-amino acid-water system is based on ethanolamine, and amine substances are added to construct a mixed alcoholamine solution, which is then mixed with a water-soluble amino acid to obtain the obtained product;

[0027] The molar ratio of the ethanolamine to the amine substance is 1:1 to 1.5;

[0028] The concentration of the water-soluble amino acid is 0.45 to 0.85 mol / L;

[0029] The amine substance is one or more of methylethanolamine, triethanolamine and 2-amino-2-methyl-1-propanol;

[0030] The concentration of the composite absorbent is 1 to 3 mol / L;

[0031] The volume ratio of the composite absorbent used in the calcium source solid waste leaching system and the CO2 absorption system is 2.5-10.

[0032] Furthermore, in the step of introducing CO2 flue gas into the CO2 absorption system and using the composite absorbent to absorb CO2, the gas-liquid ratio of the CO2 flue gas to the composite absorbent is 5 to 10 m / s. 3 / L, the time for absorbing CO2 is 0.75~1.25h;

[0033] The calcium source solid waste is added into the calcium source solid waste leaching system and a composite absorbent is used to make the calcium 2+In the leaching and dissolution steps, an indirect external field ultrasound is added, the output frequency of the ultrasound is 200 to 300 Hz, and the indirect action lasts 10 to 15 seconds per minute;

[0034] The solid-liquid ratio of calcium source solid waste to composite absorbent is 70-100g / L, Ca 2+ The leaching and dissolution time is 0.75 to 1.25 hours.

[0035] Furthermore, the CO3-rich 2- Absorbent and Ca-rich 2+ The leaching agent is placed under ultrasonic and mechanical stirring to complete the carbonation reaction through liquid-liquid ion mixing. 2+ The volume ratio of the leaching agent to the CO2-rich absorbent is 2 to 5, and the carbonation reaction to pH change rate is ≤ 0.0025 min -1 , stop the carbonation reaction, and after the reaction is completed, let it stand for 3 to 6 hours.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention discloses a calcium source solid waste leaching-absorption-carbonation reaction circulation system based on biomineralization, which comprises a CO2 absorption system, a calcium source solid waste leaching system and a carbonation reaction system. A composite absorbent is used to respectively realize the absorption of CO2 flue gas and the leaching of calcium source solid waste. At the same time, a liquid product collection system is respectively connected to the CO2 absorption system and the calcium source solid waste leaching system to realize the recycling of the composite absorbent. The composite absorbent serves as both a leaching agent for the calcium source solid waste and a low-concentration CO2 gas absorbent, and each independently completes the leaching and absorption processes. The carbonation reaction is a liquid-liquid reaction, which avoids the shortcomings of a bubbling carbonation reaction mode in which the gas-liquid interface mass transfer rate is low and the uneven bubble particle size leads to differences in the dissolution of CO2 bubbles that affect changes in product characteristics.

[0038] The present invention also discloses a method for a calcium source solid waste leaching-absorption-carbonation reaction cycle based on biomineralization, which utilizes a composite alcohol amine-amino acid-water system absorbent to realize a calcium source solid waste leaching-absorption-carbonation cycle process. Compared with the existing absorption-mineralization integration and leaching-mineralization cycle processes, the method has the following differences: 1) the composite absorbent serves as both a leaching agent for the calcium source solid waste and a low-concentration CO2 gas absorbent, and each independently completes the leaching and absorption processes; 2) the carbonation reaction is a liquid-liquid ion reaction, which avoids the shortcomings of a bubbling carbonation reaction mode in which the gas-liquid interface mass transfer rate is low and the uneven bubble particle size leads to differences in the dissolution of CO2 bubbles that affect changes in product characteristics; 3) the process and system react under normal temperature and mild conditions, which reduces the requirements for equipment and reduces the energy consumption required for the process. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a structural diagram of the calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization of the present invention;

[0040] Among them: 1-washing tower; 2-separator; 3-first-stage CO2 absorption device; 4-second-stage CO2 absorption device; 51-CO2 composite absorbent supply device; 51-leaching Ca 2+ Composite absorbent supply device; 6-CO2 absorption liquid storage tank; 7-residual gas discharge device; 8-first water pump; 9-Ca leaching 2+ Device; 10-Ca 2+ Post-extraction liquid storage tank; 11-ultrasonic device; 12-second water pump; 13-carbonation reaction device; 14-solid product collection tank; 15-drying box; 16-liquid product standing tank; 17-liquid storage tank. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0042] The first aspect of the present invention discloses a calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization, comprising a CO2 absorption system, a calcium source solid waste leaching system and a carbonation reaction system; wherein the CO2 absorption system and the calcium source solid waste leaching system both use a composite absorbent to achieve the absorption of CO2 flue gas and the leaching of calcium source solid waste; subsequently, the CO2-rich absorbent obtained after the CO2 flue gas absorption is combined with the Ca-rich absorbent obtained after the calcium source solid waste leaching. 2+ The absorbent undergoes a carbonation reaction in the carbonation reaction system to obtain calcium carbonate and a regenerated composite absorbent; the regenerated composite absorbent then enters the CO2 absorption system and the calcium source solid waste leaching system respectively to achieve the recycling of the composite absorbent.

[0043] The second aspect of the present invention is to disclose a method for a calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization, comprising the following steps:

[0044] Step 1: Prepare a composite absorbent of a composite alcoholamine-amino acid-water system, and allocate the amount of the composite absorbent in the CO2 absorption system and the calcium source solid waste leaching system; wherein the composite absorbent of the composite alcoholamine-amino acid-water system is a composite alcoholamine solution constructed by adding a dibasic or tribasic alcoholamine solution such as TEA to MEA as a basis, and then adding amino acids;

[0045] Step 2: introducing the CO2 flue gas into the CO2 absorption system and using the composite absorbent to absorb CO2 to obtain a CO2-rich absorbent;

[0046] Step 3: Combine CO2-rich absorbent and Ca-rich 2+ The extractant is placed in a carbonation reaction system to carry out a carbonation reaction, and after the reaction is completed, the obtained reaction solution is filtered to obtain a solid product and a liquid product;

[0047] Step 4: Collect the solid product through the solid product collection system, place the liquid product into the liquid product collection system, and then add it to the CO2 absorption system and the calcium source solid waste leaching system respectively to realize the recycling of the composite absorbent.

[0048] Preferably, the composite absorbent of the composite alcoholamine-amino acid-water system relies on amino acids to release H + Neutralization of alkaline calcium source solid waste and amino groups in polyol amines to Ca 2+ The complexation of Ca 2+ Leaching; At the same time, the polyvalent complex alcohol amine solution meets the requirements of fast CO2 absorption rate, large absorption load and chemical regeneration, and can also neutralize the acidic environment of the reaction between amino acids and CO2, solving the problem of slow reaction with CO2 and low absorption load caused by neutral amino acids; According to experimental data, it is found that the single 3 mol / LMEA solution Ca 2+ The leaching concentration is 1000 mg / L, Ca 2+ The utilization rate is 30%, 1.5mol / LMEA+1.5mol / LTEA composite alcoholamine solution Ca 2+ The leaching concentration is 2800 mg / L, Ca 2+ The utilization rate was 75%. The dissolution capacity of MEA-TEA composite alcohol amine absorbent with different ratios on calcium ions in the purified ash of calcium carbide plant was significantly higher than that of single MEA, and it showed a significant increasing trend with the increase of TEA addition ratio. When the TEA addition ratio was 1:1.5, the Ca 2+ The utilization rate is the highest, and as the addition ratio increases, Ca 2+ The utilization rate dropped significantly. At the same time, the experiment found that when 0.5 mol of glycine was added to the 1.5 mol / LMEA+1.5 mol / LTEA composite alcohol amine solution, the CO2 absorption load reached 0.9650 mol / L, and the Ca 2+ The leaching concentration was 7391 mg / L, but after adding more than 1 mol of glycine, the Ca 2+The leaching concentration gradually decreased. At the same time, a higher-value nano-calcium carbonate product was found to be produced. The principle behind this is that the biomineralized organic matrix regulates the biomineral morphology and structure. The experiment verified the feasibility of simultaneous leaching, absorption, and carbonation using a composite alcoholamine-amino acid-water system absorbent, and determined the type and concentration of the composite absorbent mixture. In summary, MEA (ethanolamine) was used as the base, and di- or tri-alkanolamine solutions such as MDEA (methylethanolamine), TEA (triethanolamine), and AMP (2-amino-2-methyl-1-propanol) were added to construct a composite alcoholamine solution with a mixing ratio of 1:1 to 1.5. 0.45 to 0.85 mol / L of amino acids (any one or more combinations of glycine, alanine, or arginine with both basic amino groups and acidic hydroxyl groups) were added. Water was added to adjust the composite absorbent concentration to 1 to 3 mol / L, with the water solubility of the amino acids exceeding 95 g / L.

[0049] Preferably, it is Ca-rich 2+ Leaching agent and rich CO3 2- When the absorbent volume ratio γ>5, Ca 2+ The utilization rate is less than 30%. If γ<2, the carbonate ions produced in the absorption sub-process are not completely reacted. In order to ensure the economic benefits of the system and the yield of calcium carbonate, γ=2~5 must be satisfied.

[0050] Preferably, before the CO2 flue gas is introduced into the CO2 absorption system, the CO2 concentration in the CO2 flue gas is greater than 15%, and the gas-liquid ratio of the CO2 flue gas to the composite absorbent flow is less than 5m 3 / L, the CO2 absorption load in the composite absorbent is reduced and the utilization rate of the composite absorbent is low; if the gas-liquid ratio is greater than 10m 3 / L, the CO2 in the CO2 flue gas is not fully captured and the carbon emission reduction effect is not significant; therefore, the gas-liquid ratio is selected to be 5-10m 3 / L, under normal temperature and pressure, and a stirring rate of 200-600r / min, the absorption time is 0.75-1.25h to generate a CO2-rich absorbent.

[0051] Preferably, the calcium source solid waste leaching is calcium source solid waste with a total CaO content of more than 15%, a particle size of about 1 to 5 mm, and a specific surface area of ​​15 to 20 m 2 / g, the concentration of heavy metal elements (such as vanadium and chromium) in the ash is less than 0.005%, the solid-liquid ratio of calcium source solid waste to composite absorbent is less than 70g / L, and the leaching of Ca 2+ As the concentration decreases, the subsequent carbonation reaction rate decreases, and the yield of the product calcium carbonate decreases; if the solid-liquid ratio is greater than 100g / L, the solid surface area in the container increases, making it difficult to stir, and Ca dissolves. 2+ A large amount of Ca is attached to the surface of solid waste particles. 2+The utilization rate is reduced; therefore, the solid waste and the composite absorbent are immersed for 0.75-1.25 h under the conditions of a solid-liquid ratio of 70-100 g / L, normal temperature and pressure, and a stirring rate of 300-600 r / min, to generate a Ca 2+ absorbent.

[0052] Preferably, the CO3 2- absorbent and the Ca 2+ rich solution are placed in a carbonation reaction system for carbonation reaction under the conditions of normal temperature and pressure, and a stirring rate of 200-600 r / min, until the pH change rate is less than or equal to 0.0025 min -1 , and the reaction is stopped; due to the slow release of carbonate ions in the filtrate after the reaction, the absorbent filtrate is allowed to stand for 3-6 h to maximize the carbonation product.

[0053] Preferably, the solid product is returned to the CO2 absorption system and the calcium source solid waste leaching system after secondary filtration, and the volume ratio β remains unchanged; however, the composite absorbent is irreversibly consumed during the circulation process, so that the Ca 2+ leaching concentration is less than 70% A (Ca 2+ concentration A = 7000-12000 mg / L) and the absorption load is less than 80% B (CO2 absorption load B = 0.8-1.5 mol / L), then a part of the new composite absorbent needs to be replaced.

[0054] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and in the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0055] Example 1

[0056] A calcium source solid waste leaching-absorption-carbonation reaction circulation method based on biomineralization, comprising the following steps:

[0057] S1: preparing a composite absorbent: 1.5 mol TEA + 1.5 mol MEA + 0.5 glycine, and adding water to prepare 100 mL of the composite absorbent;

[0058] S2: CO2 absorption: Take 20 mL of the composite absorbent in S1, introduce gas at 1 L / min, gas composition: 85% CO2, 15% N2, at room temperature (20-25°C), stirring rate 500 r / min, absorb for 1 h, and the measured CO2 absorption load is 0.965 mol / L;

[0059] S3: Calcium source solid waste leaching: The calcium source solid waste is obtained from fly ash particles removed from the purified flue gas emitted by a calcium carbide furnace in a certain place. It is mainly composed of calcium-containing components, most of which exist in the form of CaO, CaCO3, Ca(OH)2 and Ca2SiO4, with a conversion of CaO to about 58.83%. Table 1 shows the detailed chemical composition of dust ash A;

[0060] Table 1 Chemical composition of dust ash A

[0061]

[0062] Take 50ml of the composite absorbent in S1 with a solid-liquid ratio of 70g / L, stir at room temperature at a rate of 500r / min, soak for 1h, and measure Ca 2+ The dissolution concentration is 0.330 mol / L;

[0063] S4: Carbonation reaction: According to the reaction between carbonate in the mother liquor and Ca in the leaching solution 2+ Concentration, take the CO2 rich solution and Ca in step 2 and 3 respectively 2+ The rich liquid, volume ratio is 1:2, at room temperature, stirring rate is 500r / min, reaction for 1h, after filtration, the remaining absorbent mother liquor is transferred to a standing tank and left for two days;

[0064] S5: Product treatment: Filter the carbonation reaction solution, wash and dry the solid product to obtain 0.43 g of calcium carbonate product, and filter it at irregular intervals during the standing period to obtain 0.919 g of calcium carbonate product;

[0065] S6: Regeneration of composite absorbent cycle: the filtrate in step 5 is divided into V j and V i , enter the absorption and leaching containers respectively, and enter the next leaching-absorption-carbonation reaction cycle.

[0066] Example 2

[0067] A calcium source solid waste leaching-absorption-carbonation reaction cycle method based on biomineralization, comprising the following steps:

[0068] S1: Prepare composite absorbent: 1.5 mol TEA + 1.5 mol MEA + 1 mol glycine, add water to make 100 mL of composite absorbent;

[0069] S2: CO2 absorption: Take 10 mL of the composite absorbent in S1, pass in gas at 0.5 L / min, gas composition: 85% CO2, 15% N2, at room temperature (20-25°C), stirring rate 500 r / min, absorb for 1 h, measured CO2 absorption load is 1.1609 mol / L;

[0070] S3: Calcium source solid waste leaching: The calcium source solid waste is taken from the fly ash particles removed from the purified flue gas of a certain calcium carbide furnace, which is mainly composed of calcium-containing components, most of which exist in the form of CaO, CaCO3, Ca(OH)2 and Ca2SiO4, and the equivalent CaO is about 45.6%, Table 2 is the detailed chemical composition of the dust removal ash B;

[0071] Table 2 Chemical composition of dust removal ash B

[0072]

[0073] Take 50 ml of the composite absorbent in S1, solid-liquid ratio is 90 g / L, at room temperature, stirring rate 500 r / min, leaching for 1 h, measured Ca 2+ dissolution concentration is 0.542 mol / L;

[0074] S4: Carbonation reaction: According to the concentration of carbonate in the absorption mother liquor and Ca 2+ in the leaching solution, respectively take the CO2-rich liquid and Ca 2+ rich liquid in steps two and three, volume ratio is 1:2.4, at room temperature, stirring rate 500 r / min, react for 1 h, after filtration, the remaining absorption mother liquor is transferred to a standing tank and stands for two days;

[0075] S5: Product treatment: filter the carbonation reaction solution, wash and dry the solid product to obtain 0.175 g of calcium carbonate product, and at the same time, filter the product calcium carbonate 0.56 g during the standing period;

[0076] S6: Regeneration of composite absorbent cycle: divide the filtrate in step five into V j and V i , respectively, into the absorption and leaching containers, and enter the next leaching-absorption-carbonation reaction cycle.

[0077] Example 3

[0078] A calcium source solid waste leaching-absorption-carbonation reaction cycle method based on biomineralization, comprising the following steps:

[0079] S1: Preparation of composite absorbent: 1.5 mol TEA + 1.5 mol MEA + 0.75 mol glycine, add water to prepare 100 mL of composite absorbent;

[0080] S2: CO2 absorption: Take 20 ml of the composite absorbent in S1, introduce gas at 1 L / min, gas composition: 85% CO2, 15% N2, at room temperature (20-25°C), stirring rate 500 r / min, absorb for 1 h, and the measured CO2 absorption load is 1.2768 mol / L;

[0081] S3: Calcium Source Solid Waste Leaching: The calcium source solid waste was collected from a fly ash sample collected from a dust collector of an industrial coal-fired boiler in a certain province. The converted CaO content was approximately 33.5%. Table 3 shows the detailed chemical composition of the fly ash.

[0082] Table 3 Chemical composition of fly ash

[0083]

[0084] Take 50ml of the composite absorbent in S1 with a solid-liquid ratio of 90g / L, stir at room temperature at a rate of 500r / min, soak for 1h, and measure Ca 2+ The dissolution concentration is 0.452 mol / L;

[0085] S4: Carbonation reaction: According to the reaction between carbonate in the mother liquor and Ca in the leaching solution 2+ Concentration, take the CO2 rich solution and Ca in step 2 and 3 respectively 2+ The rich liquid, volume ratio is 1:3.3, at room temperature, stirring rate is 500r / min, reaction is 1h, after filtration, the remaining absorbent mother liquor is transferred to a standing tank and left to stand for two days;

[0086] S5: Product treatment: Filter the carbonation reaction solution, wash and dry the solid product to obtain 0.858 g of calcium carbonate product, and filter it periodically during the standing period to obtain 1.02 g of calcium carbonate product;

[0087] S6: Regeneration of composite absorbent cycle: the filtrate in step 5 is divided into V j and V i , enter the absorption and leaching containers respectively, and enter the next leaching-absorption-carbonation reaction cycle.

[0088] like Figure 1 As shown, the present invention discloses a calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization, comprising a washing tower 1, a separator 2, a primary CO2 absorption device 3, a secondary CO2 absorption device 4, a CO2 composite absorbent supply device 51, a CO2 post-absorption liquid storage tank 6, a residual gas air discharge device 7, a first water pump 8, a leaching Ca 2+ Device 9, Ca 2+The post-leaching storage tank 10, the ultrasonic device 11, the second water pump 12, the carbonation reaction device 13, the solid product collection tank 14, the drying box 15, the liquid product standing tank 16 and the storage tank 17; wherein the CO2 absorption system comprises that the inlet end of the washing tower 1 is connected with a CO2 flue gas source, and the outlet end is connected with the inlet end of the separator 2; the liquid outlet end of the separator 2 is connected with the top of the washing tower 1; the gas outlet end of the separator 2 is connected with the inlet end of the primary CO2 absorption device 3, the outlet end of the primary CO2 absorption device 3 is connected with the inlet end of the secondary CO2 absorption device 4; the outlet end of the secondary CO2 absorption device 4 is connected with the inlet end of the post-CO2 absorption storage tank 6; the outlet end of the post-CO2 absorption storage tank 6 is connected with the inlet end of the carbonation reaction device 13; the secondary CO2 absorption device 4 is connected with the remaining gas air discharge device 7; the first water pump 8 is arranged between the post-CO2 absorption storage tank 6 and the carbonation reaction device 13;

[0089] Ca 2+ The inlet end of the device 9 is connected with a calcium source solid waste source, and the Ca 2+ The outlet end of the device 9 is connected with the post-leaching storage tank 10; the Ca 2+ The inlet end of the post-leaching storage tank 10 is connected; the Ca 2+ The outlet end of the post-leaching storage tank 10 is connected with the inlet end of the carbonation reaction device 13; the Ca 2+ The composite absorbent supply device 52 is connected with the Ca 2+ The bottom of the device 9 is communicated; the Ca 2+ The bottom of the device 9 is further connected with the ultrasonic device 11, and the Ca 2+ The second water pump 12 is arranged between the outlet end of the post-leaching storage tank 10 and the carbonation reaction device 13.

[0090] The outlet end of the carbonation reaction device 13 is connected with the inlet end of the solid product collection tank 14; the outlet end of the solid product collection tank 14 is connected with the drying box 15; the outlet end of the carbonation reaction device 13 is connected with the inlet end of the liquid product standing tank 16; the solid product outlet end of the liquid product standing tank 16 is connected with the inlet end of the solid product collection tank 14; the liquid product outlet end of the standing tank 16 is connected with the storage tank 17; wherein the storage tank 17 is respectively connected with the CO2 composite absorbent supply device 51 and the Ca 2+ The composite absorbent supply device 52 is connected; the CO2 composite absorbent supply device 51 and the Ca 2+ The composite absorbent supply device 52 is placed with a composite absorbent, so that the CO2 flue gas is absorbed and the calcium source solid waste is leached.

[0091] The working method of the calcium source solid waste leaching-absorption-carbonation reaction circulating system based on biological mineralization disclosed by the application is as follows:

[0092] The prepared CO2 composite absorbent is supplied to the device 51 and the Ca leaching 2+ The composite absorbent of the composite alcoholamine-amino acid-water system in the composite absorbent supply device 52 is respectively put into the CO2 composite absorbent supply device 51 and the Ca2 leaching system according to the amount of composite absorbent allocated in the CO2 absorption system and the calcium source solid waste leaching system. 2+ The composite absorbent supply device 52 then passes the CO2 flue gas into the scrubber 1, where it is scrubbed and dust-removed, passes through the separator 2, and enters the primary CO2 absorption device 3 and the secondary CO2 absorption device 4. After contacting the composite absorbent, a CO2-rich absorbent is generated, which is then placed in the CO2-absorbed liquid storage tank 6 and pumped into the carbonation reaction device 13 via the first water pump 8.

[0093] Calcium source solid waste is added to leaching Ca 2+ In device 9, with leaching Ca 2+ The composite absorbent in device 9 contacts the Ca 2 + Dissolved, the obtained Ca 2+ After the leaching liquid is filtered, Ca 2+ After leaching, the liquid storage tank 10 is used to obtain Ca-rich 2+ absorbent, which will be rich in Ca 2+ The absorbent is pumped into the carbonation reaction device 13 through the second water pump 12;

[0094] The CO2-rich absorbent and Ca-rich absorbent in the carbonation reaction device 13 2+ The absorbent undergoes a carbonation reaction. After the reaction is completed, the obtained reaction solution is filtered, and the obtained solid product (calcium carbonate) is sequentially placed in a solid product collecting tank 14 and a drying box 15. The obtained liquid product is placed in a liquid product standing tank 16 for standing. After standing, the obtained solid product after standing enters the solid product collecting tank 14, and the liquid product after standing enters the liquid storage tank 17.

[0095] The liquid product in the liquid storage tank 17 is the regenerated composite absorbent, which enters the next cycle after the leaching-absorption dosage is reasonably distributed.

[0096] The biomineralization method used in this invention is divided into several stages, including pre-organization of organic macromolecules, recognition of organic / inorganic interface molecules, and morphology control of organic matter. Based on the biomineralization mechanism, a polyolamine-amino acid-water system composite absorbent is used as an organic macromolecule to absorb and leach, generating negatively charged CO3 2- The structural surface and the number of critical sites for nucleation of epitaxial units Ca 2+, completing the pre-assembly of organic macromolecules. During the carbonation reaction, organic groups at the organic-inorganic interface and inorganic ions in the crystals recognize and complement each other in ligand structure, promoting the nucleation and growth of calcium carbonate. Simultaneously, the addition of amino acids to the composite absorbent imposes certain constraints and restrictions on the growth of calcium carbonate crystals in three dimensions, resulting in the production of nanoscale calcium carbonate products.

[0097] Based on the biomineralization of Ca in organic macromolecules 2+ With inorganic ion CO3 2- The principle of reaction and regulation of the formation of inorganic calcium carbonate at the interface and the effect of the composite absorbent on CO2 absorption performance and selectivity of Ca 2+ The present invention proposes a calcium source solid waste leaching-absorption-carbonation cycle process and system based on a reactive composite absorbent. The composite alcohol amine solution is coupled with amino acids to obtain a chemically regenerated bifunctional composite alcohol amine-amino acid-water system absorbent, which combines the alcohol amine solution's ability to efficiently absorb low-concentration CO2 in flue gas with the amino acid solution's high selectivity for dissolving calcium ions in calcium source solid waste. After leaching-absorption, the calcium-rich solid waste is treated with a certain volume ratio. 2+ The carbonation reaction of the mixture of absorbent and CO2-rich absorbent is a liquid-liquid reaction, which avoids the shortcomings of low gas-liquid interface mass transfer rate in the bubbling carbonation reaction mode and low gas-solid interface reaction rate in the absorbent regeneration process, and solves the problem that the product calcium carbonate adheres to solid waste, which limits its utilization value.

[0098] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization, characterized in that: It includes a CO2 absorption system, a calcium source solid waste leaching system and a carbonation reaction system; the CO2 absorption system and the calcium source solid waste leaching system are respectively connected to the carbonation reaction system; the carbonation reaction system also includes a solid product collection system and a liquid product collection system; Composite absorbents are placed in both the CO2 absorption system and the calcium source solid waste leaching system, respectively used to achieve the absorption of CO2-containing flue gas and the leaching of calcium source solid waste; the composite absorbent is a composite absorbent of a composite alcoholamine-amino acid-water system; The liquid product collection system is connected to the CO2 absorption system and the calcium source solid waste leaching system respectively to achieve the recycling of the composite absorbent; The CO2 absorption system comprises a washing tower (1), a separator (2), a primary CO2 absorption device (3), a secondary CO2 absorption device (4), a CO2 composite absorbent supply device (51) and a CO2 post-absorption liquid storage tank (6); The CO2 absorption system comprises a washing tower (1) whose inlet end is connected to a CO2 flue gas source, and whose outlet end is connected to an inlet end of a separator (2); a liquid outlet end of the separator (2) is connected to the top of the washing tower (1); a gas outlet end of the separator (2) is connected to an inlet end of a primary CO2 absorption device (3); an outlet end of the primary CO2 absorption device (3) is connected to an inlet end of a secondary CO2 absorption device (4); an outlet end of the secondary CO2 absorption device (4) is connected to an inlet end of a CO2 post-absorption liquid storage tank (6); and an outlet end of the CO2 post-absorption liquid storage tank (6) is connected to a calcium source solid waste leaching system. The CO2 composite absorbent supply device (51) is communicated with the bottom of the primary CO2 absorption device (3) and the secondary CO2 absorption device (4) respectively; The top of the secondary CO2 absorption device (4) is also connected to a residual gas air discharge device (7); a first water pump (8) is also provided between the outlet end of the CO2 post-absorption liquid storage tank (6) and the calcium source solid waste leaching system; The calcium source solid waste leaching system includes leaching Ca 2+ Device (9), leaching Ca 2+ Composite absorbent supply device (52) and Ca 2 + After leaching, the liquid storage tank (10); the leaching Ca 2+ The inlet end of the device (9) is connected to the calcium source solid waste source; the leaching Ca 2+ The outlet of the device (9) and Ca 2+ The inlet end of the liquid storage tank (10) after leaching is connected; the Ca 2+ The outlet end of the post-leaching liquid storage tank (10) is connected to the calcium source solid waste leaching system; The leaching of Ca 2+ Composite absorbent supply device (52) and leaching Ca 2+ The bottom of the device (9) is connected; The leaching of Ca 2+ The bottom of the device (9) is also connected to an ultrasonic device (11); the Ca 2+ A second water pump (12) is further connected between the outlet end of the post-leaching liquid storage tank (10) and the calcium source solid waste leaching system.

2. A calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization according to claim 1, characterized in that: The carbonation reaction system comprises a carbonation reaction device (13), a solid product collection system and a liquid product collection system; the outlet end of the CO2 absorption liquid storage tank (6), the Ca 2+ The outlet ends of the post-leaching liquid storage tank (10) are respectively connected to the inlet ends of the carbonation reaction device (13); and the outlet ends of the carbonation reaction device (13) are respectively connected to a solid product collection system and a liquid product collection system.

3. A calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization according to claim 2, characterized in that: The solid product collection system comprises a solid product collection tank (14) and a drying box (15); the liquid product collection system comprises a liquid product standing tank (16) and a liquid storage tank (17); the outlet end of the carbonation reaction device (13) is connected to the inlet end of the solid product collection tank (14); the outlet end of the solid product collection tank (14) is connected to the drying box (15); the outlet end of the carbonation reaction device (13) is connected to the inlet end of the liquid product standing tank (16); the solid product outlet end of the liquid product standing tank (16) is connected to the inlet end of the solid product collection tank (14); and the liquid product outlet end of the standing tank (16) is connected to the liquid storage tank (17).

4. The calcium source solid waste leaching-absorption-carbonation reaction cycle system based on biomineralization according to claim 3, characterized in that: The liquid storage tank (17) is respectively connected to the CO2 composite absorbent supply device (51) and the Ca leaching 2+ The composite absorbent supply device (52) is connected; the CO2 composite absorbent supply device (51) and the leaching Ca 2+ The composite absorbent supply device (52) is provided with composite absorbent to achieve the absorption of CO2 flue gas and the leaching of calcium source solid waste.

5. A calcium source solid waste leaching-absorption-carbonation reaction cycle method based on biomineralization, characterized in that: The following steps are involved: Prepare a composite absorbent of a composite alcoholamine-amino acid-water system and allocate the amount of the composite absorbent in the CO2 absorption system and the calcium source solid waste leaching system; The CO2 flue gas is introduced into the CO2 absorption system and the composite absorbent is used to absorb the CO2 to obtain a CO2-rich absorbent; Calcium source solid waste is added into the calcium source solid waste leaching system and composite absorbent is used to make it Ca 2+ Leaching and dissolution to obtain Ca-rich 2+ absorbent; The CO2-rich absorbent and the Ca-rich 2+ The absorbent is placed in a carbonation reaction system to carry out a carbonation reaction, and after the reaction is completed, the obtained reaction solution is filtered to obtain a solid product and a liquid product; The solid product is collected through a solid product collection system, and the liquid product is placed in a liquid product collection system, and then added to a CO2 absorption system and a calcium source solid waste leaching system respectively to realize the recycling of the composite absorbent.

6. The calcium source solid waste leaching-absorption-carbonation reaction cycle method based on biomineralization according to claim 5, characterized in that: The composite absorbent of the composite alcoholamine-amino acid-water system is based on ethanolamine, and amine substances are added to form a mixed alcoholamine solution, which is then mixed with a water-soluble amino acid to obtain the composite absorbent; The molar ratio of the ethanolamine to the amine substance is 1:1-1.5; The concentration of the water-soluble amino acid is 0.45-0.85 mol / L; The amine substance is one or more of methylethanolamine, triethanolamine and 2-amino-2-methyl-1-propanol; The concentration of the composite absorbent is 1 to 3 mol / L; The volume ratio of the composite absorbent used in the calcium source solid waste leaching system and the CO2 absorption system is 2.5-10.

7. The calcium source solid waste leaching-absorption-carbonation reaction cycle method based on biomineralization according to claim 5, characterized in that: In the step of introducing CO2 flue gas into the CO2 absorption system and using the composite absorbent to absorb CO2, the gas-liquid ratio of the CO2 flue gas to the composite absorbent is 5-10m / s. 3 / L, the time for absorbing CO2 is 0.75~1.25h; The calcium source solid waste is added into the calcium source solid waste leaching system and a composite absorbent is used to make the calcium 2+ In the leaching and dissolution steps, an indirect external field ultrasound is added, the output frequency of the ultrasound is 200-300 Hz, and the indirect action lasts 10-15 seconds per minute; The solid-liquid ratio of calcium source solid waste to composite absorbent is 70~100g / L, Ca 2+ The leaching and dissolution time is 0.75~1.25h.

8. The calcium source solid waste leaching-absorption-carbonation reaction cycle method based on biomineralization according to claim 5, characterized in that: Rich in CO3 2- Absorbent and Ca-rich 2+ The leaching agent is placed under ultrasonic and mechanical stirring to complete the carbonation reaction through liquid-liquid ion mixing. 2+ The volume ratio of the leaching agent to the CO2-rich absorbent is 2~5, and the carbonation reaction to pH change rate is ≤0.0025min -1 , stop the carbonation reaction, and after the reaction is completed, let it stand for 3~6 hours.

Images