Blast furnace gas carbon capture and sintering machine head ash treatment process and device

Abstract

The invention relates to a blast furnace gas carbon capture and sintering machine head ash treatment process and device, and the process comprises the following steps: S1, carrying out absorption treatment on blast furnace gas by using a lean amine solution as an absorbent to obtain a rich amine solution; s2, mixing the amine-rich liquid with the sintering machine head ash, and removing precipitates after a first precipitation reaction to obtain a first filtrate; s3, a heavy metal trapping agent and a flocculating agent are added into the first filtrate, precipitates are removed after a second precipitation reaction, and second filtrate is obtained; s4, the second filtrate is subjected to evaporative crystallization, and amine steam and inorganic salt are recycled. According to the method, CO2 in the amine-rich liquid is removed through the sintering machine head ash, steam loss is avoided, the carbon capture cost is reduced, meanwhile, alkali needed in traditional machine head ash treatment is replaced with the amine-rich liquid, the dosage of heavy and impurity removal agents is reduced, and the cost is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of steel smelting, and particularly relates to a blast furnace gas carbon capture and sintering machine head ash treatment process and device. BACKGROUND

[0002] For long process smelting, blast furnace gas is the main carrier of CO2 emission in the steel smelting process, accounting for more than 30% of total carbon emissions; on the other hand, the blast furnace gas also contains sulfides such as H2S and COS, so simultaneous desulfurization and decarburization is required. However, due to the large fluctuation of CO2 content and the presence of impurities in the blast furnace gas, the existing carbon capture process is not suitable, resulting in high absorbent loss and high steam consumption, greatly increasing the cost of desulfurization and decarburization.

[0003] Sintering machine head ash is an important hazardous waste in the steel smelting production process, which is the dust collected by electrostatic precipitators during the sintering process in the steel plant, and has high contents of potassium, sodium and chlorine elements (K is more than 10 wt.%, Na is more than 5 wt.% and Cl is more than 20 wt.%). If the sintering machine head ash is directly returned to the steel plant for sintering and reuse, the alkali metals such as potassium and sodium and the Cl element will accumulate in the sintering process, causing increased sintering energy consumption, grate bar clogging and blast furnace clogging and other hazards. Currently, the sintering machine head ash is mainly treated by water washing-heavy removal / impurity removal-evaporation crystallization to separate and purify the above elements and produce potassium and sodium salt (mainly KCl and NaCl) products. However, this process requires a large amount of heavy removal and impurity removal reagents, resulting in high process cost. SUMMARY

[0004] The present application aims to overcome the above technical deficiencies and provide a blast furnace gas carbon capture and sintering machine head ash treatment process and device to solve the technical problems of high absorbent loss in the carbon capture process and high cost due to the need for a large amount of heavy removal and impurity removal reagents in the treatment of sintering machine head ash in the prior art.

[0005] To achieve the above technical purposes, the technical solution provided by the present application is as follows: In a first aspect, the present application provides a blast furnace gas carbon capture and sintering machine head ash treatment process, comprising the following steps: S1, using lean amine solution as an absorbent to absorb and treat blast furnace gas to obtain rich amine solution; S2, mixing the rich amine solution with sintering machine head ash, removing the precipitate after a first precipitation reaction to obtain a first filtrate; S3, adding a heavy metal capture agent and a flocculating agent to the first filtrate, removing the precipitate after a second precipitation reaction to obtain a second filtrate; and S4, evaporating and crystallizing the second filtrate to recover amine steam and inorganic salt.

[0006] Secondly, the present invention provides a blast furnace gas carbon capture and sintering machine head ash treatment device, comprising an absorption tower, a first-stage stirred tank, a second-stage stirred tank, and a multi-effect evaporation system. The absorption tower is used to absorb blast furnace gas through a lean amine solution to generate a rich amine solution, and then sends the rich amine solution into the first-stage stirred tank. The first-stage stirred tank is used to mix the rich amine solution with the sintering machine head ash to carry out a first precipitation reaction, and after the first precipitation reaction, a first filtrate is obtained by separation. The second-stage stirred tank is used to mix the first filtrate with a heavy metal trapping agent and a flocculant to carry out a second precipitation reaction, and after the second precipitation reaction, a second filtrate is obtained by separation. The multi-effect evaporation system is used to evaporate and crystallize the second filtrate to recover amine vapor and inorganic salts.

[0007] Compared with the prior art, the beneficial effects of the present invention include: This invention uses lean amine liquid as an absorbent to absorb and treat blast furnace gas, absorbing carbon and sulfur such as CO2 and H2S to form a rich amine liquid. After carbon and sulfur removal, the blast furnace gas can be directly discharged in compliance with emission standards without further treatment after power generation. The rich amine liquid is then mixed with sintering machine head ash, allowing the effective components in the machine head ash to dissolve into the rich amine liquid. Furthermore, the rich amine liquid, after absorbing CO2 and H2S, forms a large amount of carbonate and hydrogen sulfide ions, which react with the calcium in the machine head ash. 2+ After the reaction produces a precipitate, the precipitate is removed by filtration to complete the initial heavy metal removal. The resulting first filtrate undergoes a second precipitation reaction under the action of a heavy metal trapping agent and a flocculant to complete the deep impurity removal. The resulting second filtrate mainly includes amine solution, K salt, and Na salt, and the amine vapor and salt products can be recovered by evaporation. This invention utilizes sintering die head ash to remove CO2 from amine-rich solution, avoiding steam loss and reducing carbon capture costs. At the same time, the amine-rich solution replaces the alkali required in traditional die head ash treatment, reducing the amount of heavy metal removal and impurity removal agents used and greatly reducing costs. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the process for blast furnace gas carbon capture and synergistic sintering machine head ash treatment according to the present invention. Figure 2 This is a schematic diagram of the blast furnace gas carbon capture and sintering machine head ash treatment device of the present invention; wherein, 1-absorption tower; 2-upper section cooler of absorption tower; 3-lower section cooler of absorption tower; 4-first stage stirred tank; 5-first stage filter press; 6-second stage stirred tank; 7-second stage filter press; 8-multi-effect evaporation system; 9-amine liquid cooler; Figure 3 This is a schematic diagram of the workflow of the present invention. Detailed Implementation

[0009] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0010] The present application provides a process of coupling blast furnace gas carbon capture and sintering machine head ash treatment, by coupling the desorption step of the capture process and the heavy removal step of the machine head ash treatment process, solving the problems of large steam consumption in the blast furnace gas desulfurization and decarburization process and the use of a large amount of impurity removal reagent in the machine head ash treatment process.

[0011] In the conventional carbon capture process, the carbonates formed by the rich amine solution need to be decomposed by heating to release CO2, so that the rich amine solution becomes lean amine solution again for reuse. The production of 1 ton of CO2 requires the consumption of 1-1.5 tons of steam, and the cost of steam accounts for more than 50% of the operating cost of carbon capture.

[0012] On the other hand, the sintering machine head ash has high potassium, sodium and chlorine elements. In the conventional sintering machine head ash purification treatment process, water washing-heavy removal / impurity removal-evaporation crystallization is mainly used for treatment, but various reagents need to be added to precipitate impurity cations. Among them, the addition amount of soda ash for precipitating Ca 2+ , Mg 2+ is the largest, accounting for more than 50% of the cost of sintering machine head ash reagents.

[0013] In view of the defects of high absorbent loss in carbon capture process and high cost caused by large amount of heavy and impurity removal reagents in sintering machine head ash treatment, the present application provides a blast furnace gas carbon capture and sintering machine head ash treatment process and device, which cooperatively treats blast furnace gas carbon capture and sintering machine head ash in the steel industry. While decarburizing and desulfurizing the blast furnace gas in the steel industry, the alkali metals such as potassium and sodium and chlorine elements in the sintering machine head ash are also removed. Decarburization and desulfurization treatment effectively reduces the emission of carbon and sulfur pollution, and the removal of alkali metals and other treatments in the machine head ash avoids the hazards of increased sintering energy consumption, grate bar clogging and subsequent blast furnace clogging caused by the accumulation of these elements. While ensuring the treatment effect, the treatment cost is effectively reduced.

[0014] In a first aspect, referring to Figure 1 , the present application provides a blast furnace gas carbon capture and sintering machine head ash treatment process, comprising the following steps: S1, using lean amine solution as absorbent to absorb and treat blast furnace gas to obtain rich amine solution; S2, mixing the rich amine solution with the sintering machine head ash, removing the precipitate after the first precipitation reaction to obtain the first filtrate; S3, adding heavy metal capture agent and flocculating agent to the first filtrate, removing the precipitate after the second precipitation reaction to obtain the second filtrate; S4, the second filtrate is evaporated and crystallized, and the amine vapor and inorganic salt are recovered.

[0015] In the present application, the blast furnace gas is mixed with the lean amine solution, the lean amine solution absorbs CO2, H2S and COS as an absorbent to become rich amine solution, enters the next process, the carbon and sulfur removed gas is discharged up to standard; the rich amine solution is mixed with the sintering machine head ash, in the process of the machine head ash dissolving in the rich amine solution, a large amount of carbonate and hydrogen sulfide ions are formed after the rich amine solution absorbs CO2 and H2S, which reacts with the Ca 2+ , Pb 2+ and other cations in the machine head ash to generate water-insoluble carbonate and hydrogen sulfide salt precipitates, the precipitates are removed, the preliminary removal of the impurity cations in the machine head ash is completed, and the first filtrate after preliminary purification is obtained. The first filtrate is subjected to a second precipitation reaction by sequentially adding a heavy capture agent (heavy metal capture agent) and a flocculating agent, the precipitates are removed, and the second filtrate after purification is obtained. The second filtrate is subjected to multi-effect evaporation, and the amine solution is discharged in the form of steam; the reduction of the amine solution leads to the crystallization of K and Na salts, and the separation into products.

[0016] Preferably, in step S1, the components of the lean amine solution include 5-25% NH3, 5-25% ethanolamine (MEA), and the balance is water.

[0017] Further preferably, the total mass fraction of NH3 and ethanolamine in the lean amine solution is not more than 30%.

[0018] In the present application, if the effective component content in the lean amine solution is too low, the amount of amine solution used in the absorption of CO2 and H2S is too large, the concentration of K and Na ions dissolved in the amine solution when mixed with the machine head ash is low, more water needs to be evaporated in the subsequent evaporation crystallization, and the energy consumption is large; if the content is too high, the amount of amine solution used in the absorption of CO2 and H2S is too small, there is not enough water to completely leach the K and Na ions in the machine head ash, and the product yield is low; the present application uses a lean amine solution composed of ammonia and organic amine to treat blast furnace gas, which is beneficial to improve the absorption effect of carbon and sulfur.

[0019] Preferably, in step S1, the lean amine solution is used to absorb and treat the blast furnace gas, specifically, the lean amine solution is sprayed to make the blast furnace gas and the lean amine solution counterflow contact, and the volume flow ratio of the blast furnace gas to the lean amine solution is (90-130):1.

[0020] Preferably, in step S2, the mass ratio of the rich amine solution to the sintering machine head ash is (2-3):1.

[0021] Preferably, in step S2, the first precipitation reaction is carried out under stirring, and the stirring time is 20-45 min.

[0022] Preferably, in step S3, the pH value of the first filtrate is controlled to be 9-12 before adding the heavy metal capturing agent; the amount of the heavy metal capturing agent is 0.5-1% of the mass of the first filtrate; and the amount of the flocculant is 1-3% of the mass of the first filtrate.

[0023] In the present application, the pH value of the first filtrate is controlled to be 9-12 to avoid acid corrosion to the equipment, and the amounts of the heavy metal capturing agent and the flocculant are controlled to avoid waste of reagents on the basis of ensuring removal of heavy metals and impurities.

[0024] Preferably, in step S3, the heavy metal capturing agent is a mixture of Na2S and TMT-15 in a mass ratio of 1:1.

[0025] Preferably, in step S3, the flocculant comprises polyacrylamide (PAM).

[0026] Preferably, in step S3, the second precipitation reaction is performed after the heavy metal capturing agent and the flocculant are added and stirring is performed for 20-45 min.

[0027] In the present application, the time of the precipitation reaction is controlled to avoid excessive energy consumption on the basis of ensuring complete reaction.

[0028] Preferably, in step S4, the amine vapor is condensed and returned to step S1 as lean amine liquid. In the present application, the amine vapor is reused after cooling, thereby effectively saving cost.

[0029] Preferably, the first precipitation reaction and the second precipitation reaction are both performed by plate-and-frame filter pressing to remove the precipitates.

[0030] In a second aspect, referring to Figure 2 The present application provides a blast furnace gas carbon capture and sintering machine head ash treatment device, which comprises an absorption tower 1, a first-stage stirring kettle 4, a second-stage stirring kettle 6, and a multi-effect evaporation system 8, wherein, The absorption tower 1 is used for absorbing blast furnace gas by lean amine liquid to generate rich amine liquid, and the rich amine liquid is sent to the first-stage stirring kettle 4; The first-stage stirring kettle 4 is used for mixing the rich amine liquid with sintering machine head ash to perform a first precipitation reaction, and a first filtrate is obtained after separation; The second-stage stirring kettle 6 is used for mixing the first filtrate with a heavy metal capturing agent and a flocculant to perform a second precipitation reaction, and a second filtrate is obtained after separation; The multi-effect evaporation system 8 is used for performing evaporation crystallization on the second filtrate, recovering amine vapor, and recovering inorganic salt.

[0031] Preferably, the lower end of the absorption tower 1 is provided with a blast furnace gas inlet, the upper end is provided with a lean amine liquid inlet, the top is provided with a gas outlet, and the bottom is provided with a liquid outlet; the liquid outlet of the absorption tower 1 is connected with the inlet of the first stage stirring kettle 4, the outlet of the first stage stirring kettle 4 is connected with the inlet of the first stage filter press 5, the liquid outlet of the first stage filter press 5 is connected with the inlet of the second stage stirring kettle 6, the outlet of the second stage stirring kettle 6 is connected with the inlet of the second stage filter press 7, and the liquid outlet of the second stage filter press 7 is connected with the inlet of the multi-effect evaporation system 8.

[0032] Preferably, the absorption tower 1 is further provided with an upper absorption tower cooler 2 and a lower absorption tower cooler 3; the upper absorption tower cooler 2 is used to control the temperature of the liquid in the upper part of the absorption tower to be 50-60℃, and the lower absorption tower cooler 3 is used to control the temperature of the liquid in the lower part of the absorption tower to be 30-40℃.

[0033] Further preferably, two-stage gas-liquid separation devices are arranged in the absorption tower 1 to form a three-stage spraying structure, and the upper absorption tower cooler 2 and the lower absorption tower cooler 3 are respectively arranged corresponding to the two-stage gas-liquid separation devices; the liquid separated by the two-stage gas-liquid separation devices returns to the absorption tower after being controlled in temperature by the upper absorption tower cooler 2 and the lower absorption tower cooler 3 respectively.

[0034] Specifically, from the starting stage, the present application includes three-stage amine liquid spraying; the lean amine liquid in the first stage spraying absorbs the blast furnace gas to obtain first-stage absorption liquid, which returns to the absorption tower 1 after being controlled in temperature by the upper absorption tower cooler 2, and is used as the second-stage spraying liquid; the second-stage spraying liquid returns to the absorption tower 1 after being controlled in temperature by the lower absorption tower cooler 3, and is used as the third-stage spraying liquid; and the third-stage spraying liquid is the rich amine liquid; the amine liquid of the present application returns to the absorption tower 1 after being controlled in temperature by the upper absorption tower cooler 2 and the lower absorption tower cooler 3, so that the temperature of the amine liquid can be accurately controlled; in the present application, the upper part of the absorption tower is controlled by kinetics, and the temperature is maintained at 50-60℃, which can promote the reaction rate to accelerate; and the lower part of the absorption tower is controlled by thermodynamics, and the absorption process is exothermic, so that maintaining a lower temperature is beneficial to the reaction equilibrium to move to the right, and improves the capacity of the absorption liquid to absorb CO2.

[0035] Preferably, the present application further includes an amine liquid cooler 9, which is used to condense the amine vapor discharged from the multi-effect evaporation system 8 to form lean amine liquid and send it into the absorption tower 1.

[0036] Preferably, the multi-effect evaporation system 8 includes 2-5 single-effect evaporators, which are all heated by steam.

[0037] Referring to Figure 2 and Figure 3During the working process of the present application, the coal gas enters from the bottom of the absorption tower 1 and flows to the top, and is in countercurrent contact with the lean amine liquid sprayed at the top of the absorption tower 1, and the carbon (CO2), sulfur (H2S and / or COS) in the coal gas is removed by the amine liquid to become desulfurized and decarbonized coal gas, which can be directly discharged after reaching the standard after burning for power generation without treatment. The lean amine liquid flows downward from the top of the tower, and a large amount of heat is released during the absorption of H2S and CO2 and the like, and the amine liquid passes through the upper section cooler 2 and the lower section cooler 3 of the absorption tower in turn and returns to the absorption tower, and the heat is removed through the above two coolers to control the temperature. The amine liquid becomes rich amine liquid due to the absorption of a large amount of H2S and CO2 and the like, and contains a large amount of carbonate and hydrogen sulfide ions.

[0038] The rich amine liquid and the head ash are simultaneously introduced into the first stage stirring tank 4 for stirring and amine washing to remove heavy metals, and the cations (K + , Na + , Zn 2+ , Ca 2+ , Cu 2+ , Pb 2+ , Fe 3+ , Fe 2+ ) in the head ash are first dissolved in the rich amine liquid, and the carbonate and hydrogen sulfide ions in the rich amine liquid mainly react with Ca 2+ , Pb 2+ and the like to form a precipitate, and after filtration separation through the first stage filter press 5, the filtrate still contains K + , Na + , Zn 2+ , Cu 2+ , Fe 3+ , Fe 2+ . The first filtrate enters the second stage stirring tank 6 for deep removal of impurities, and according to the need, caustic soda can be added first to adjust the pH of the first filtrate, then heavy trapping agent is added, and heavy metal ions such as Zn 2+ , Cu 2+ , Fe 3+ , Fe 2+ in the first filtrate are removed by reaction precipitation, and finally a flocculating agent is added to promote the aggregation of the precipitate. After passing through the second stage filter press 7, only K + , Na + cations are left in the second filtrate.

[0039] The second filtrate enters the multi-effect evaporation system 8, and the amine liquid is evaporated using steam heating, and the amine vapor is condensed after passing through the amine cooler 9 to become lean amine liquid again and return to the absorption tower 1 for repeated use. K + , Na + cations are precipitated in the form of chloride salt and sulfate salt to obtain inorganic salt products.

[0040] The present application utilizes the fact that the head ash contains a large amount of Ca2+ The carbon dioxide in the amine solution is removed by the reaction of the carbonate in the amine solution and Ca 2+ The reaction generates calcium carbonate, removes the CO2 in the amine solution, avoids the loss of steam, and greatly reduces the cost of carbon capture. At the same time, the use of amine solution instead of the alkali required in the traditional treatment of machine head ash can completely eliminate the use of caustic soda, greatly reducing the cost.

[0041] The present application will be further described in detail through specific examples. To avoid repetition, the components of the blast furnace gas and the sintering machine head ash treated are described as shown in Table 1 and Table 2 below, respectively.

[0042] Table 1 Components of blast furnace gas

[0043] Note: The main components are expressed in percentage. Since H2S and COS are trace components, and the amount of main components is quite different, they are expressed in mg / Nm 3 .

[0044] Table 2 Main components of sintering machine head ash

[0045] Example 1 A blast furnace gas carbon capture and sintering machine head ash treatment process, comprising the following steps: S1, the blast furnace gas enters from the bottom of absorption tower 1 and flows to the top, with a flow rate of 2400 Nm 3 / h (displacement under standard conditions); countercurrent contact with the absorbent sprayed at the top of absorption tower 1, the use amount of absorbent is 24.5 m 3 / h, and the absorbent is a lean amine solution composed of 15% NH3, 15% MEA and water. Due to the large amount of heat released by the reaction, the upper section cooler 2 of the absorption tower controls the temperature of the liquid returning to the tower to be 50℃, and the lower section cooler 3 of the absorption tower controls the temperature of the liquid returning to the tower to be 35℃, obtaining rich amine solution at the bottom of the tower.

[0046] In this case, the CO2 concentration in the desulfurized and decarburized gas at the top of the tower is reduced to about 1%, H2S is not detected, and COS is reduced to about 11 mg / Nm 3 , and the capture rate of CO2 reaches 95%.

[0047] S2, the rich amine solution is used at a flow rate of 24.6 m 3The flow rate of the solution (absorbing CO2 and H2O volume increase) and the amount of the head ash 8.4 t / h are simultaneously introduced into the first stirring tank 4 for stirring for 30 min. After passing through the first filter press 5, the first filtrate obtained under the same conditions is taken three times for testing ion composition. At the same time, the same proportion of pure water and head ash are stirred and filtered according to the same method to obtain a comparative filtrate for testing ion composition. In the head ash, K and Na exist in the form of chloride salt, which is dissolved in the rich amine solution and water in a large amount, and the ion concentration is relatively high. Cu, Fe and other ions exist in the form of oxides and chlorides, among which only the form of chlorides can be dissolved, and thus the ion concentration is relatively low. The specific results are shown in Table 3.

[0048] Table 3 Test results of the first filtrate of Example 1

[0049] As can be seen from Table 3, the contents of Ca and Pb decrease significantly, and Fe and Cu decrease to a certain extent, proving that the amine solution and the above-mentioned ions have a precipitation reaction, and proving that the amine solution can completely replace the traditional pure alkali reagent.

[0050] S3, the first filtrate enters the second stirring tank 6, without adjusting the pH, directly adding 271.2 kg / h of heavy capture agent (a mixture of Na2S and TMT-15 with a mass ratio of 1:1) and 600 kg / h of flocculant to remove Zn 2+ , Cu 2+ , Fe 3+ , Fe 2+ and other heavy metal ions by reaction precipitation (stirring for 20 min), and after passing through the second filter press 7, the second filtrate is obtained. The ion composition of the second filtrate is shown in Table 4.

[0051] Table 4 Test results of the second filtrate

[0052] As can be seen from Table 4, only K + , Na + cations remain in the second filtrate, and heavy metals are basically removed.

[0053] S4, the second filtrate enters the multi-effect evaporation system 8, and the amine solution is evaporated by using steam heating. The amine vapor is condensed by the amine cooler 9 to become lean amine solution again, and the lean amine solution 24 m 3 / h is recovered, in which NH3 and ethanolamine basically maintain a concentration of 15%. The CO2 content in the lean amine solution is 0, which is detected by titration. K + , Na + cations are precipitated in the form of chlorides and sulfates, with a yield of about 1.55 t / h and 0.26 t / h, respectively.

[0054] Example 2 The difference from Example 1 is only that the proportion of components in the absorbent is adjusted, NH3 accounts for 5%, ethanolamine accounts for 25%, and the absorbent dosage is 23 m 3 / h; other steps and conditions are the same as in Example 1.

[0055] After passing through the first-stage filter press, the first filtrate is taken for ion component testing, and is compared with the comparative filtrate in Example 1. As shown in Table 5 below.

[0056] Table 5 Test results of the first filtrate of Example 2

[0057] As can be seen from Table 5, Example 2 also achieves a relatively good precipitation effect (similar to the results of the first filtrate in Example 1), proving that the amine solution can replace the soda reagent.

[0058] Comparative Example 1 The difference from Example 1 is only that NH3 is removed from the absorbent, only ethanolamine accounts for 30%, the lower-stage cooler 3 of the absorption tower is not used, and the absorbent flow rate is 24.7 m 3 / h; other steps and conditions are the same as in Example 1.

[0059] After passing through the first-stage filter press, the first filtrate is taken for ion component testing, and is compared with the comparative filtrate in Example 1. As shown in Table 5 below.

[0060] Table 6 Test results of the first filtrate of Comparative Example 1

[0061] As can be seen from Table 6, there are still a large amount of Ca and Pb ions remaining, and the precipitation effect is poor. The reason for this is that only ethanolamine is used in the amine solution, and after absorbing CO2, only carbamate is generated, which reacts with Ca 2+ , Pb 2+ to generate precipitates at a rate that is not fast enough.

[0062] Comparative Example 2 The difference from Example 1 is only that the upper-stage cooler 2 and the lower-stage cooler 3 of the absorption tower are not used, and other steps and conditions are the same as in Example 1.

[0063] After testing, the temperature in the absorption tower rises to a maximum of 85℃, the CO2 concentration in the desulfurized and decarburized coal gas at the top of the tower is 13.54%, and H2S+COS is 62.3 mg / Nm 3 , which indicates that the desulfurization and decarburization effect is poor.

[0064] Comparative Example 3 The difference from Example 2 is that the sintering machine head ash is used in 25t / h, which makes the ratio of amine liquid to machine head ash close to 1:1, and other steps are the same as Example 2.

[0065] After the first stage filter press, the first filtrate is taken to test the ion composition as shown in Table 7.

[0066] Table 7 Test results of the first filtrate of Comparative Example 3

[0067] As shown in Table 7, the sintering machine head ash dosage is increased by 3 times, and the ion concentration is not 3 times of Example 2, which is represented by K and Na. This shows that there are still ions in the solid that have not been leached into water, and the removal effect on calcium is not obvious. After calculation, compared with the leaching rate of K of 75% and Na of 83% in Example 2, the leaching rate of K in this comparative example is only about 40%, and the leaching rate of Na is only about 51%.

[0068] The specific embodiments of the application described above do not constitute a limitation on the protection scope of the application. Any various other corresponding changes and modifications made according to the technical concept of the application shall be included in the protection scope of the claims of the application.

Claims

1. A process for co-processing blast furnace gas carbon capture and sintering machine head ash treatment, characterized in that, Includes the following steps: S1, using lean amine liquid as absorbent to absorb and treat blast furnace gas to obtain rich amine liquid; S2, the amine-rich liquid is mixed with sintering machine head ash, and the precipitate is removed after the first precipitation reaction to obtain the first filtrate; S3, add heavy metal precipitant and flocculant to the first filtrate, remove the precipitate after the second precipitation reaction, and obtain the second filtrate; S4, the second filtrate is evaporated and crystallized to recover amine vapor and inorganic salts.

2. The blast furnace gas carbon capture and sintering machine head ash treatment process according to claim 1, characterized in that, In step S1, the components of the lean amine solution, by mass percentage, include: 5-25% NH3, 5-25% ethanolamine, and the balance being water.

3. The blast furnace gas carbon capture and sintering machine head ash treatment process according to claim 1, characterized in that, In step S1, the absorption treatment involves spraying the blast furnace gas with the lean amine solution, wherein the flow rate ratio of the blast furnace gas to the lean amine solution is (90-130):

1.

4. The blast furnace gas carbon capture and sintering machine head ash treatment process according to claim 1, characterized in that, In step S2, the mass ratio of the rich amine solution to the sintering machine head ash is (2-3):1; the first precipitation reaction is carried out under stirring conditions for 20-45 minutes.

5. The blast furnace gas carbon capture and sintering machine head ash treatment process according to claim 1, characterized in that, In step S3, the pH of the first filtrate is controlled to be 9-12 before adding a heavy metal precipitant; the amount of heavy metal precipitant is 0.5-1% of the mass of the first filtrate; the amount of flocculant is 1-3% of the mass of the first filtrate.

6. The blast furnace gas carbon capture and sintering machine head ash treatment process according to claim 1, characterized in that, In step S3, the re-capturing agent is a mixture of Na2S and TMT-15 in a mass ratio of 1:1; the flocculant includes polyacrylamide.

7. The blast furnace gas carbon capture and sintering machine head ash treatment process according to claim 1, characterized in that, In step S3, the second precipitation reaction is carried out after the heavy metal precipitator and flocculant are added and stirred for 20 to 45 minutes.

8. The blast furnace gas carbon capture and sintering machine head ash treatment process according to claim 1, characterized in that, In step S4, the amine vapor is condensed and returned to step S1 as a lean amine solution.

9. A device for co-processing blast furnace gas carbon capture and sintering machine head ash treatment in the processing technology described in any one of claims 1-8, characterized in that, It includes an absorption tower, a first-stage stirred tank, a second-stage stirred tank, and a multi-effect evaporation system, among which, The absorption tower is used to absorb blast furnace gas through lean amine liquid to produce rich amine liquid, and the rich amine liquid is sent into the first stage stirred tank. The first-stage stirred tank is used to mix the rich amine liquid with the sintering machine head ash to carry out the first precipitation reaction. After the first precipitation reaction is completed, the first filtrate is obtained by separation. The second-stage stirred tank is used to mix the first filtrate with a heavy metal precipitant and a flocculant to carry out a second precipitation reaction. After the second precipitation reaction is completed, the second filtrate is separated. The multi-effect evaporation system is used to evaporate and crystallize the second filtrate, and to recover amine vapor and inorganic salts.

10. The blast furnace gas carbon capture and sintering machine head ash treatment device according to claim 9, characterized in that, The absorption tower is also equipped with an upper section cooler and a lower section cooler. The upper section cooler is used to control the liquid temperature in the upper section of the absorption tower to be 50-60℃, and the lower section cooler is used to control the liquid temperature in the lower section of the absorption tower to be 30-40℃.

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