Fine desulfurization and decarbonization combined device for blast furnace gas

Abstract

The utility model discloses a blast furnace gas fine desulfurization and decarburization combined device, and relates to the technical field of blast furnace gas desulfurization and decarburization. The system comprises an absorption system and a regeneration analysis system, wherein the absorption system comprises an absorption tower and a first intermediate cooling system; a plurality of absorption filler layers are arranged in the absorption tower at intervals, and the first intermediate cooling system is connected among the plurality of absorption filler layers; the regeneration analysis system comprises an analysis tower and a rich and lean liquid heat exchanger; a rich liquid outlet in the bottom of the absorption tower, a barren liquid spraying inlet above each absorption filler layer, a barren liquid outlet in the side surface of the bottom of the desorption tower and a rich liquid inlet above the desorption filler layer are all connected with the barren and rich liquid heat exchanger. The absorption tower is provided with the first intermediate cooling system, the absorbent is pumped and cooled and then sent back into the absorption tower, the temperature in the absorption tower is kept stable, and high efficiency of desulfurization and decarburization is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of blast furnace gas desulfurization and decarburization technology, more specifically, it is a blast furnace gas fine desulfurization and decarburization device. BACKGROUND

[0002] The steel industry produces blast furnace gas as a byproduct during the ironmaking process, which is an important source of gas fuel for steel enterprises. Blast furnace gas has the characteristics of low heat value but high yield. Its main components include N2 (53%-57%), CO (21%-26%), CO2 (16%-22%), H2 (1%-4%), and a small amount of hydrocarbons and O2. Although the nitrogen content in blast furnace gas is relatively high, the combustible components such as carbon monoxide and hydrogen make blast furnace gas a valuable fuel resource. However, blast furnace gas is not a pure energy source, as it contains a certain amount of harmful substances, especially sulfides, with a content of about 100-200 mg / m 3 These sulfides are mainly composed of carbonyl sulfide (COS) and hydrogen sulfide (H2S), as well as trace amounts of carbon disulfide (CS2), sulfides, and mercaptans. Among them, the proportions of organic sulfur COS and inorganic sulfur H2S in the total sulfur content are about 70% and 30%, respectively. The presence of these sulfides not only poses a pollution threat to the environment but also poses a challenge to the utilization of blast furnace gas.

[0003] Fine desulfurization of blast furnace gas has become an urgent task for the steel industry to achieve ultra-low emission targets. Although current fine desulfurization technology for blast furnace gas has attracted widespread attention in China and several experimental projects have been carried out, unfortunately, there have been no successful cases of long-term stable operation to date.

[0004] At present, carbon capture technology is still in its early stages of application in the steel industry, with a low level of development.

[0005] In summary, blast furnace gas is currently facing the dual urgent needs of carbon emission reduction and fine desulfurization technology. The development of fine desulfurization and carbon capture technology for blast furnace gas is of great significance to the sustainable development of the steel industry. The development of related devices is crucial for the steel industry to achieve pollution reduction, carbon reduction, and ultra-low emission targets. This technology not only has broad market prospects but also has significant social and environmental benefits. Currently, traditional wet absorbents have exposed many problems in practical applications, such as the inability to simultaneously remove organic and inorganic sulfides, poor regeneration performance, high regeneration energy consumption, severe equipment corrosion, and large solvent loss.

[0006] In view of this, there is an urgent need to develop a blast furnace gas fine desulfurization and synergistic decarbonization device to overcome the limitations of traditional absorbents, thereby improving the desulfurization and decarbonization efficiency, reducing energy consumption and costs, and effectively reducing equipment corrosion and solvent loss, and promoting the steel industry to develop in a green and sustainable direction. Utility Model Content

[0007] The purpose of the utility model is to overcome the shortcomings of the above-mentioned background technology and to provide a blast furnace gas fine desulfurization and coordinated decarbonization device.

[0008] To achieve the above-mentioned object, the technical solution of the present invention is as follows: a blast furnace gas fine desulfurization and coordinated decarbonization device, characterized in that: it includes an absorption system and a regeneration and decomposition system, the absorption system includes an absorption tower and a first intermediate cooling system; multiple layers of absorption filler are arranged at intervals in the absorption tower, the bottom of the absorption tower is connected to the original blast furnace gas, and the top is provided with a clean blast furnace gas outlet; the first intermediate cooling system is connected between the multiple layers of absorption filler;

[0009] The regeneration and decomposition system includes a decomposition tower and a lean and rich liquid heat exchanger; the decomposition tower is provided with multiple layers of decomposition filler layers at intervals, the bottom of the decomposition tower is connected to the external steam supply, and the top is provided with a decomposition exhaust gas outlet;

[0010] The rich liquid outlet at the bottom of the absorption tower, the lean liquid spray inlet above each absorption packing layer, the lean liquid outlet on the bottom side of the decomposition tower, and the rich liquid inlet above the decomposition packing layer are all connected to the lean and rich liquid heat exchanger.

[0011] The first intermediate cooling system controls the temperature in the absorption tower to be maintained at 40-50°C, and the temperature in the desorption tower to be maintained at 110-120°C.

[0012] The above technical solution also includes a pretreatment system, through which the original blast furnace gas is connected to the absorption tower, and the pretreatment system is connected to the second intermediate cooling system.

[0013] In the above technical solution, a washing system is also included. A water washing packing layer is arranged above the absorption packing layer in the absorption tower. One end of the washing system is connected to the cooling water washing inlet above the water washing packing layer, and the other end is connected to the cooling water washing outlet below the water washing packing layer.

[0014] In the above technical solution, the multi-layer absorbent filler layer includes a first absorbent filler layer, a second absorbent filler layer and a third absorbent filler layer which are sequentially arranged from bottom to top; the first intermediate cooling system is arranged between the first absorbent filler layer and the second absorbent filler layer;

[0015] The multi-layer analytical filler layer includes a first analytical filler layer, a second analytical filler layer and a third analytical filler layer which are sequentially arranged from bottom to top.

[0016] In the above technical solution, the net blast furnace gas outlet is arranged below the resolving waste gas outlet.

[0017] Compared with the prior art, the utility model has the following advantages:

[0018] 1) The utility model discloses a kind of high-temperature blast furnace gas fine desulfurization and decarburization device, which can be used for solving the problems that traditional wet absorption agent cannot simultaneously remove organic sulfur and inorganic sulfur, and the service life of absorption agent is limited, and the problems of high energy consumption and equipment corrosion are solved.

[0019] 2) The utility model has efficient purification and synergistic treatment capacity: the device of the utility model can effectively treat various impurities in blast furnace gas; after blast furnace gas enters from the bottom of absorption tower, organic sulfur impurities such as CO2, H2S and COS in the gas can be adsorbed, the gas is purified, and the purified gas can meet the use requirements of downstream users; this simultaneous treatment capacity for various impurities effectively improves the quality of blast furnace gas and provides high-quality energy for subsequent production links of the steel industry; the unique absorption system and the use of two-phase absorbent realize fine desulfurization and carbon capture, overcome the problem that traditional process cannot simultaneously effectively treat various impurities, solve the two key problems of carbon emission reduction and fine desulfurization in one process, and greatly improve the treatment efficiency of the steel industry in environmental protection.

[0020] 3) The utility model optimizes the performance of the absorbent: the two-phase absorbent of the utility model is a high-efficiency binary phase separation system combined with a phase separation agent and a conventional alcohol amine chemical absorbent; by optimizing the proportion of different components, a superior SF / DEA / H2O phase change system is obtained, which has good phase separation ratio, absorption load and absorption capacity; the performance advantages of the two-phase absorbent can more effectively capture acidic impurity gases in blast furnace gas, improve the absorption efficiency and ensure the purification effect of the entire process on the gas; the addition of active components AMP and piperazine PZ further optimizes the performance of the absorbent; piperazine PZ can react with COS to generate a zwitterion, thereby improving the removal rate of COS through deprotonation; the steric effect of AMP increases the chemical activity of the amino group, accelerates the hydrolysis conversion rate of COS and promotes the absorption of COS; the combined action of the two significantly improves the removal efficiency of H2S, COS and CO2; in experiments, the absorption amount of H2S, COS and CO2 of the absorbent compounded with different active components is obviously improved, realizing the deep removal of these impurities.

[0021] 4) The utility model has good process adaptability and stability: the structure design of the absorption tower of the utility model is reasonable, which learns from the internal structure of the traditional absorption tower, and the inner part can select the tray or the filler form, and the special designed filler (metal material supplemented with special treatment process) is used in the lower part to strengthen the main absorption reaction; this design not only makes the process flexible to adjust according to actual needs, but also ensures the stability and efficiency of the absorption process; the segmented filler design cooperates with the collector and the redistributor, ensuring that the gas and liquid in the filler fully contact, making the entire absorption process more stable and reliable; the entire process forms a stable cycle, and the cycle process from the absorption tower to the desorption tower and back to the absorption tower makes the absorbent work continuously and effectively, ensures the stability of the process in long-term operation and overcomes the shortcomings of the traditional process in long-term stable operation.

[0022] 5) The absorption tower is provided with a first intermediate cooling system, the absorbent is extracted, cooled and then sent back into the absorption tower, the temperature in the absorption tower is maintained stable, and high efficiency of desulfurization and decarburization is ensured; the decarburization and desulfurization reaction is an exothermic reaction, according to the chemical equilibrium principle, reducing the temperature is beneficial to the reaction to proceed in the positive direction, that is, beneficial to the absorption of carbon dioxide and sulfur; due to the heat release of the reaction, a temperature gradient is formed in the absorption tower, leading to uneven distribution of gas and liquid, after the intermediate cooling system is arranged, the temperature of the absorbent at different heights in the tower is effectively adjusted, and the adverse effect of the temperature gradient on the flow of gas and liquid is reduced; after the cooled absorbent is sent back into the tower, the gas-liquid contact condition can be improved, the distribution of the gas in the tower is more uniform, and the gas-liquid mass transfer efficiency is improved; through the first intermediate cooling system, the temperature of the absorbent is reduced, the reaction equilibrium in the absorption tower can be moved to the right, the solubility of carbon dioxide and sulfur in the absorbent is increased, and thus the absorption efficiency is improved; high temperature can promote the volatilization of the absorbent, especially some absorbent components with high volatility, through the first intermediate cooling system, the temperature of the absorbent is reduced, and the volatilization loss of the absorbent can be significantly reduced.

[0023] 6) The utility model discloses reduce the cost, improve the economy: in the absorbent aspect, the optimization binary phase separation system and the addition of active component are reduced the solvent loss while improving the absorption efficiency, the traditional wet method absorbent has the problem of big solvent loss, and the utility model discloses improve the absorbent performance and stability, reduce the cost increase due to solvent loss, in the regeneration process, through the influence of regeneration temperature on acid gas regeneration rate, determine the best regeneration temperature interval of 110 DEG C-120 DEG C, in the interval, can guarantee that acid gas total regeneration rate is greater than 85%, and can avoid too high regeneration energy consumption, compared with the traditional process, effectively reduce the regeneration energy consumption, reduce the operation cost, improve the economy of whole process, help in steel industry large-scale popularization and application.

[0024] 7) The utility model discloses reduce the equipment complexity and cost: the utility model discloses through reasonable process design and absorbent performance make the design and operation of equipment more simplified, for example, shorter phase separation time avoids the problem of the phase separator volume increase due to the phase separation time is too long, thereby reduces the equipment cost, at the same time, the stable operation of process reduces the maintenance cost and equipment updating cost due to equipment corrosion, breakdown and other problems, improves the overall service life and economy of equipment. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the structural schematic diagram of the utility model.

[0026] Figure 2 It is the structural schematic diagram of the absorption tower.

[0027] Figure 3 It is the structural schematic diagram of the analysis tower.

[0028] Wherein, 100-absorption system, 110-absorption tower, 1111-pure blast furnace gas outlet, 1112-blast furnace gas inlet, 112-rich liquid outlet, 113-lean liquid spray inlet, 1141-cooling water washing inlet, 1142-cooling water washing outlet, 120-first intermediate cooling system, 121-absorbent extraction interface, 122-extraction device, 123-circulating water cooler, 130-multilayer absorption packing layer, 131-first absorption packing layer, 132-second absorption packing layer, 133-third absorption packing layer, 140-water washing packing layer, 200-regeneration desorption system, 210-desorption tower, 211-desorption waste gas outlet, 212-lean liquid outlet, 213-rich liquid inlet, 220-lean and rich liquid heat exchanger, 221-rich liquid pump, 222-lean liquid pump, 230-multilayer desorption packing layer, 231-first desorption packing layer, 232-second desorption packing layer, 233-third desorption packing layer, 241-condenser, 242-steam-water separator, 243-reboiler, 300-pre-treatment system, 310-second intermediate cooling system, 400-washing system, 500-wire mesh demister. DETAILED DESCRIPTION

[0029] The embodiments of the present application will be described in detail below with reference to the drawings, but they do not constitute limitations to the present application, and are only examples. Meanwhile, the advantages of the present application will become more apparent and easier to understand through the description.

[0030] Referring to the drawings, a blast furnace gas fine desulfurization and decarburization device is characterized by comprising an absorption system 100 and a regeneration desorption system 200, the absorption system 100 comprising an absorption tower 110 and a first intermediate cooling system 120; the absorption tower 110 is provided with a multilayer absorption packing layer 130 at intervals, and the bottom of the absorption tower 110 is connected to raw blast furnace gas, and the top is provided with a pure blast furnace gas outlet 1111; the first intermediate cooling system 120 is connected between the multilayer absorption packing layer 130;

[0031] The regeneration desorption system 200 comprises a desorption tower 210 and a lean and rich liquid heat exchanger 220; the desorption tower 210 is provided with a multilayer desorption packing layer 230 at intervals, and the bottom of the desorption tower 210 is connected to external steam, and the top is provided with a desorption waste gas outlet 211;

[0032] The rich liquid outlet 112 at the bottom of the absorption tower 110, the lean liquid spray inlet 113 above each absorption packing layer 130, the lean liquid outlet 212 at the side of the bottom of the desorption tower 210, and the rich liquid inlet 213 above the desorption packing layer 230 are all connected to the lean and rich liquid heat exchanger 220.

[0033] The first intermediate cooling system 120 controls the temperature in the absorption tower 110 to be maintained at 40-50 DEG C, and the temperature in the desorption tower 210 to be maintained at 110-120 DEG C.

[0034] The pre-treatment system 300 is further included, through which the raw blast furnace gas accesses the absorption tower 110, and the pre-treatment system 300 is connected with the second intermediate cooling system 310.

[0035] The washing system 400 is further included, and a water washing filler layer 140 is arranged above the absorption filler layer 130 in the absorption tower 110, one end of the washing system 400 accesses the cooling water inlet 1141 above the water washing filler layer 140, and the other end accesses the cooling water outlet 1142 below the water washing filler layer 130.

[0036] The multi-layer absorption filler layer 130 includes the first absorption filler layer 131, the second absorption filler layer 132 and the third absorption filler layer 133 which are sequentially and spacedly arranged from bottom to top; and the first intermediate cooling system 120 is arranged between the first absorption filler layer 131 and the second absorption filler layer 132.

[0037] The multi-layer desorption filler layer 230 includes the first desorption filler layer 231, the second desorption filler layer 232 and the third desorption filler layer 233 which are sequentially and spacedly arranged from bottom to top.

[0038] The screen demister 500 is arranged below the clean blast furnace gas outlet 1111 and below the desorption waste gas outlet 211.

[0039] An absorption agent for blast furnace gas fine desulfurization and decarburization in cooperation, characterized in that it comprises a phase separation agent, an alcohol amine chemical absorbent and water, the phase separation agent is sulfolane, and the alcohol amine chemical absorbent is diethanolamine.

[0040] The mass fraction of sulfolane accounts for 50-70%, the mass fraction of diethanolamine accounts for 15-25%, and the rest is water, and the total of the mass fraction percentages of the above components is 100%.

[0041] The active component further includes a steric-hindered amine AMP and / or piperazine PZ, the mass fraction of the steric-hindered amine AMP accounts for 0-11%, the mass fraction of the piperazine PZ accounts for 0-11%, and the mass fraction of the steric-hindered amine AMP and the piperazine PZ accounts for 0-11% in total.

[0042] In the absorption agent, the mass fraction of sulfolane accounts for 60%, the mass fraction of diethanolamine accounts for 20%, the mass fraction of the steric-hindered amine AMP accounts for 6%, and the mass fraction of the piperazine PZ accounts for 5%.

[0043] The absorption temperature of the absorption agent is 40-50 DEG C, and the regeneration temperature is 110-120 DEG C.

[0044] A method for using a high-temperature fine desulfurization and decarburization device, characterized in that the method comprises the following steps:

[0045] Step 1: preparing an absorbent composed of 60% sulfolane, 20% diethanolamine, 6% steric-hindered amine AMP, 5% piperazine PZ, and H2O, and feeding the absorbent into the absorption system 100;

[0046] Step 2: after the raw high-temperature gas is pretreated to remove impurities and reduce the temperature, the gas is fed into the absorption tower 110 from the bottom, the absorbent and the gas are reversely contacted in the absorption tower 110, the weakly acidic impurity gas in the gas is combined with the absorbent on the surface of the multi-layer absorption filler layer 130 in the absorption tower 110 under the driving of the gas partial pressure, and slight reaction heat is released; the whole reaction process continues from the upper part of the absorption tower 110 to the lower main reaction zone of the absorption tower 110, until the formed rich liquid is transported to the desorption tower 210 by the rich liquid pump 221 at the bottom of the absorption tower 110;

[0047] The absorbent simultaneously adsorbs the greenhouse gas CO2, inorganic sulfur H2S, and organic sulfur COS in the high-temperature gas, and the clean gas after purification is sent out from the clean high-temperature gas outlet 1111 and enters the downstream user;

[0048] The first intermediate cooling system 120 extracts the absorbent; the flow rate of the extracted absorbent is 10%-50% of the total circulation flow rate of the absorption tower 110. After the absorbent enters the first intermediate cooling system 120, the absorbent exchanges heat with the cooling medium; the cooled absorbent is sent back to the absorption tower 110, so that the temperature in the absorption tower 110 is maintained at 40-50℃;

[0049] Step 3: the desorption tower 210 provides a reverse reaction driving force by supplying steam, so that the rich liquid is overflowed again to form regenerated high-concentration clean acidic gas, and the regenerated absorbent solution is transported to the absorption tower 110 again by the lean liquid pump 222; the steam maintains the temperature in the desorption tower 210 at 110-120℃;

[0050] Step 4, the cycle of steps 2-3 is completed, and the fine desulfurization and decarburization of the raw high-temperature gas and the circulation and repeated use of the absorbent are completed.

[0051] The structure of the absorption tower 110 is similar to that of a conventional gas absorption tower, and is composed of a barrel body shell and inner parts; the inner parts of the absorption tower 110 draw on the conventional mature internal structure of an absorption tower, and can adopt a tray inner part or a packing inner part; the upper part of the absorption tower 110 is a main absorption section, and can adopt a tray or packing, as required by process design; the lower part of the absorption tower 110 needs to adopt packing to strengthen the main absorption reaction, and can be regular or scattered, and is consistent with the conventional packing in form but adopts metal with special treatment process to strengthen the absorption reaction process; when considering the use of packing, a segmented design is needed, and a collector and a redistributor are arranged between each layer of packing to ensure that the gas and liquid in the packing are in full contact.

[0052] The first intermediate cooling system 120 ensures that the temperature of the absorption tower 110 is maintained at 40°C, and ensures the best absorption efficiency; the absorbent extraction interface 121 is arranged at a suitable position in the middle section of the absorption tower 110, and the absorbent is extracted through the suction device 122 (such as a centrifugal pump) connected with a pipeline. The flow rate of the extracted absorbent is determined according to the processing scale of the absorption tower 110, the reaction heat generation condition, and the design parameters of the first intermediate cooling system 120 and other factors, and is generally 10%-50% of the total circulation flow rate of the absorption tower 110; after the absorbent enters the first intermediate cooling system 120, heat exchange is performed with a cooling medium; if circulating water cooling is adopted, the circulating water enters from one side of the cooler 123, is discharged from the other side after absorbing the heat of the absorbent, and the cooling degree of the absorbent is controlled by adjusting the flow rate and temperature of the circulating water; the cooled absorbent is pressurized through a delivery pump, and is sent back to a suitable position in the upper section or the lower section of the absorption tower 110 through a pipeline; the selection of the back-to-tower position should be determined according to the gas-liquid flow characteristics and reaction distribution in the absorption tower 110, to ensure that the cooled absorbent can fully contact the gas in the absorption tower 110 and continue to participate in the decarburization and desulfurization reaction, and form a good circulation system.

[0053] In actual use, the phase separation agent sulfolane (SF) selected in the utility model is combined with the alcohol amine chemical absorbent diethanolamine (DEA) to develop an efficient binary phase separation system; first, the sulfolane (SF) is combined with the alcohol amine chemical absorbent diethanolamine (DEA) to obtain an SF-based two-phase absorbent with good absorption performance; then the system is further optimized to obtain a system with the best solvent ratio; in this process, the parameters of the lean phase ratio, absorption load, absorption capacity, phase separation time and phase change load of the system are analyzed, among which the phase separation time and the phase change load have an important influence on the actual process operation; a longer phase separation time means that the absorbent needs a longer time to achieve two-phase separation during the standing process, which not only increases the complexity of the operation, but also leads to the increase of the volume of the phase separator, thereby increasing the equipment cost; at the same time, in order to effectively meet the needs of carbon capture and fine desulfurization in low-concentration blast furnace gas, a lower phase change load and a shorter phase separation time are particularly important; according to the test results, the SF, DEA and H2O phase change system has the best performance, and after optimization, the system exhibits good phase separation ratio, absorption load and absorption capacity, and the performance is stronger than that of the DEEA-based two-phase absorbent system formed by combining the phase separation agent diethylamine ethanol (DEEA) with the conventional alcohol amine chemical absorbent (such as MEA, MDEA, DEA, etc.).

[0054] According to the existing engineering experience and tests, compared with the single-phase system, the phase separation system has lower regeneration energy consumption for desulfurization and decarburization under the premise of maintaining the same absorption efficiency, which shows great energy-saving potential; as shown in Table 1, the influence of different SF+DEA ratios on the CO2 absorption load, absorption rate and phase change characteristics of the absorbent under the SF+DEA phase separation system is investigated:

[0055] Table 1

[0056]

[0057]

[0058] As shown in Table 1, under 60% SF, DEA is less than 15% and higher than 25% and does not phase separate, and within this range, as the DEA content increases, the phase separation time gradually shortens, the phase change load gradually decreases, and the absorption capacity gradually increases; under 20% DEA, as the SF content is less than 60%, it does not phase separate, but as the SF content increases, the absorption rate gradually decreases.

[0059] 60% SF+20% DEA has the best CO2 absorption load, absorption rate and phase change characteristics.

[0060] As shown in Table 2, the absorption temperature is 40-50℃, the reaction time is 120 min, the ratio of 60% SF+20% DEA is selected, the H2S / COS / CO2 in the simulated coal gas is analyzed for capture experiment, different active components are added to improve the absorption efficiency, a new blast furnace gas simultaneous desulfurization and carbon capture two-phase absorbent is obtained, and the total sulfur in the purified coal gas is less than 20 mg / Nm 3 , and the CO2 capture rate is greater than 90%.

[0061] Table 2

[0062]

[0063] As shown in Table 2, the performance of the absorbent is optimized by adding active components; piperazine PZ can react with COS to generate a zwitterion due to the active hydrogen atoms in its molecular structure, thereby significantly improving the removal rate of COS; this reaction process is prone to deprotonation, which is beneficial to the removal of COS; on the other hand, the steric hindrance amine AMP has a unique steric effect, which makes the amino group exhibit higher chemical activity, accelerates the hydrolysis conversion rate of COS, and promotes the absorption between the components and COS, thereby achieving deep removal of COS. These characteristics make piperazine PZ and steric hindrance ammonium AMP effective additives for improving the removal efficiency of H2S, COS and CO2.

[0064] When piperazine PZ and steric hindrance ammonium AMP are added at the same time, the active substances in the solution are significantly increased. These active substances promote the reaction between the absorbent and H2S; therefore, when piperazine PZ and steric hindrance ammonium AMP are contained in the solution at the same time, the absorbent exhibits higher absorption capacity and absorption rate.

[0065] Piperazine PZ can react with COS to generate a zwitterion, and this reaction process is more prone to deprotonation, thereby improving the removal rate of COS; in addition, the unique steric effect of steric hindrance amine AMP can improve the hydrolysis conversion rate of COS and promote the absorption between the absorbent components and COS; therefore, by adding appropriate steric hindrance amine AMP and piperazine PZ active components, the removal efficiency and absorption capacity of the two-phase absorbent for COS can be significantly improved.

[0066] The absorption capacity of CO2 is significantly increased after adding active components; among them, the absorption capacity of CO2 of 60% SF+20% D+6% AMP+5% PZ+H2O is 28.12 g / L, which is increased by 68.18% compared with the absorption capacity of CO2 of 60% SF+20% DEA+H2O.

[0067] In summary, the 60% SF + 20% DEA + 6% AMP + 5% PZ + H2O system can achieve efficient and deep removal of H2S, COS and CO2 after introducing the space- hindered amine AMP and piperazine PZ active substances into the system. In addition, after adding these active substances, the phase separation time of the system is significantly advanced, and the phase separation occurs 60 min earlier on the basis of 60% SF + 20% DEA, but the phase change ratio of the system is not improved.

[0068] The regeneration performance of the two-phase absorbent is a key factor for its commercial application, as it directly affects the operating cost and energy efficiency. It is particularly crucial to reduce the regeneration energy consumption while ensuring the desorption efficiency. As shown in Figure 3, with the increase of regeneration temperature, the acid gas regeneration rate shows a gradually increasing trend. However, when the regeneration temperature reaches 110°C, the increase of acid gas regeneration rate slows down, and only increases by 2.60% from 120°C to 130°C, while the regeneration energy consumption increases significantly. Therefore, considering economic applicability, the increase of acid gas regeneration rate is small at a high regeneration temperature, so the regeneration temperature range of 110°C-120°C is the best, which can ensure a high total acid gas regeneration rate of more than 85% and avoid high regeneration energy consumption.

[0069] Table 3

[0070]

[0071]

[0072] Example 1, medium-sized steel plant blast furnace gas treatment project:

[0073] Project background: A medium-sized steel plant has multiple blast furnaces with a large amount of daily blast furnace gas production. However, the original gas treatment system cannot meet the increasingly stringent environmental emission requirements, and there are problems such as high energy consumption, severe equipment corrosion, and unsatisfactory removal of impurities such as H2S, COS and CO2 in blast furnace gas.

[0074] Implementation process: install the absorption system, regeneration analysis system and supporting control system of the utility model; according to the yield and component characteristics of the blast furnace gas of the plant, design the appropriate scale of fine desulfurization absorption tower and analysis tower; the absorption tower 110 adopts the filler inner part, the lower main reaction zone selects the regular filler of metal material supplemented by special treatment process, and adopts the sectional design, each section is provided with collector and redistributor; the two-phase absorbent composed of 60% SF+20% D+6% AMP+5% PZ+H2O is deployed, and is used for the absorption system 100; after starting the system, the original blast furnace gas enters from the bottom of the absorption tower 110 through the pipeline, and is contacted with the absorbent in reverse. In the absorption tower 110, H2S, COS and CO2 and other impurities in the gas react with the absorbent, and the purified gas is output from the upper part of the absorption tower 110 and sent to the user end in the plant area, such as heating furnace; the rich liquid that has absorbed impurities is sent to the analysis tower 210 from the lower part of the absorption tower 110 by the rich liquid pump 221, and is regenerated at the temperature interval of 110 DEG C-120 DEG C, and the regenerated absorbent is sent back to the absorption tower 110 by the lean liquid pump 222 for recycling.

[0075] Implementation effect: after treatment, the content of H2S in the blast furnace gas is reduced to 10 mg / m 3 The content of COS is reduced to 5 mg / m 3 The CO2 capture rate reaches more than 80%, which fully meets the requirements of the steel plant for gas quality, and also meets the local environmental emission standards. Compared with the original treatment system, the regeneration energy consumption is reduced by about 20%, the solvent loss is reduced by about 30%, the equipment corrosion condition is obviously improved, the equipment maintenance cycle is expected to be prolonged by 1.5 times, and the operation cost and maintenance cost are greatly reduced.

[0076] Example 2, blast furnace gas purification upgrading project of large-scale steel joint enterprise:

[0077] Project background: the blast furnace gas of a large-scale steel joint enterprise is supplied to multiple production links, but the traditional desulfurization and carbon treatment process faces upgrading pressure; the enterprise faces the requirements of national ultra-low emission policy, and hopes to reduce production cost and improve energy utilization efficiency.

[0078] Implementation process: According to the large-scale processing needs of the enterprise blast furnace gas, a large-scale fine desulfurization absorption tower and a resolving tower are built, and a high-efficiency control system is equipped. The main absorption section of the upper part of the absorption tower 110 adopts the combination of trays and fillers, and the lower part adopts the scattered fillers to strengthen the main absorption reaction; the two-phase absorbent of SF / DEA / H2O phase change system is used, and according to the composition and flow of the gas, the proportion of each component of the absorbent is accurately adjusted, and an appropriate amount of steric hindrance amine AMP and piperazine PZ active components are added; the original blast furnace gas enters the absorption tower 110, and fully contacts and reacts with the absorbent in the whole absorption tower 110, and the purified gas is supplied to the rolling steel, sintering and other processes in the enterprise; the rich liquid is transported to the resolving tower 210 for regeneration, and the regeneration temperature is controlled in the best interval to ensure the acid gas regeneration rate and the performance of the absorbent.

[0079] Implementation effect: The quality of the processed blast furnace gas is significantly improved, the removal rates of H2S and COS are more than 95% and 90% respectively, the CO2 capture efficiency is increased to 85%, the pollution emission of the subsequent production link is effectively reduced, the ultra-low emission requirement is met, the regeneration energy consumption is reduced by about 23% compared with before, the solvent supplement period is prolonged, the failure rate of the equipment caused by corrosion is reduced, the overall operation cost is reduced by about 18%, and the enterprise brings significant economic benefits and environmental protection benefits.

[0080] The other parts not described belong to the prior art.

Claims

1. A high-temperature fine desulfurization and decarburization device for blast furnace gas, characterized in that: The system comprises an absorption system (100) and a regeneration and analysis system (200), the absorption system (100) comprises an absorption tower (110) and a first intermediate cooling system (120); a plurality of absorption filler layers (130) are arranged in the absorption tower (110) at intervals, the bottom of the absorption tower (110) is connected to raw blast furnace gas, and the top of the absorption tower (110) is provided with a clean blast furnace gas outlet (1111); the first intermediate cooling system (120) is connected between the plurality of absorption filler layers (130); ​ The regeneration and analysis system (200) comprises an analysis tower (210) and a lean-rich liquid heat exchanger (220); a plurality of analysis filler layers (230) are arranged in the analysis tower (210) at intervals, the bottom of the analysis tower (210) is connected to external steam, and the top of the analysis tower (210) is provided with an analysis waste gas outlet (211); The rich liquid outlet (112) at the bottom of the absorption tower (110), the lean liquid spray inlet (113) above each absorption filler layer (130), the lean liquid outlet (212) at the side of the bottom of the analysis tower (210), and the rich liquid inlet (213) above the analysis filler layer (230) are all connected to the lean-rich liquid heat exchanger (220); The first intermediate cooling system (120) controls the temperature in the absorption tower (110) to be maintained at 40-50 DEG C, and the temperature in the analysis tower (210) to be maintained at 110-120 DEG C.

2. The high-temperature fine desulfurization and decarburization device for blast furnace gas according to claim 1, characterized in that: The system further comprises a pretreatment system (300), the raw blast furnace gas is connected to the absorption tower (110) through the pretreatment system (300), and the pretreatment system (300) is connected to a second intermediate cooling system (310).

3. The high-temperature fine desulfurization and decarburization device of the blast furnace gas according to claim 1, characterized in that: The system further comprises a washing system (400), a water washing filler layer (140) is arranged above the absorption filler layer (130) in the absorption tower (110), one end of the washing system (400) is connected to a cooling water washing inlet (1141) above the water washing filler layer (140), and the other end of the washing system (400) is connected to a cooling water washing outlet (1142) below the water washing filler layer (140).

4. The high-temperature fine desulfurization and decarburization device of the blast furnace gas according to claim 2, characterized in that: The plurality of absorption filler layers (130) comprise a first absorption filler layer (131), a second absorption filler layer (132) and a third absorption filler layer (133) arranged at intervals from bottom to top; the first intermediate cooling system (120) is arranged between the first absorption filler layer (131) and the second absorption filler layer (132); The plurality of analysis filler layers (230) comprise a first analysis filler layer (231), a second analysis filler layer (232) and a third analysis filler layer (233) arranged at intervals from bottom to top.

5. The high-temperature fine desulfurization and decarburization device of the blast furnace gas according to claim 4, characterized in that: A wire mesh demister (500) is arranged below the clean blast furnace gas outlet (1111) and below the analysis waste gas outlet (211).

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