Blast furnace gas purification device and process method thereof

Abstract

The invention discloses a blast furnace gas purification device and a process method thereof. The device comprises a heat exchange unit, a washing unit, a desulfurization unit and a sulfur separation and recovery unit which are connected in sequence, wherein the outlet of the desulfurization unit for discharging the desulfurized blast furnace gas is also connected with the inlet at the lower part of the heat exchange unit, and the desulfurized blast furnace gas discharged by the desulfurization unit is conveyed into the heat exchange unit and is subjected to heat exchange with the blast furnace gas subjected to gravitational dust removal. Through the heat exchange unit, the temperature of inlet blast furnace gas is reduced, meanwhile, heat is recycled, the temperature of outlet blast furnace gas is increased, then wet dust removal, purification and desulfurization are conducted, sulfur-containing substances are directly converted into sulfur through a desulfurizing agent so that the sulfur can be recycled, separation is easy, no additional sulfur-containing solid waste is generated, and the desulfurizing agent can be conveniently regenerated and reused; the whole purification process flow is short, the TRT generating capacity can be increased, meanwhile, desulfurized blast furnace gas enters the TRT for power generation, power generation equipment is prevented from being corroded, and the service life of the equipment is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of gas purification and desulfurization, and specifically relates to a blast furnace gas purification device and a process method thereof. Background Art

[0002] Blast furnace gas is the combustible gas with the largest output in steel enterprises. It is mainly used as fuel for blast furnace hot blast furnaces, steel rolling heating furnaces, gas power generation and other user units. After gravity dust removal and bag dust removal, the blast furnace gas is sent to the residual pressure power generation (TRT), and the blast furnace gas after power generation is sent to various use points. Since blast furnace gas contains harmful substances such as sulfur and chlorine, a large amount of harmful pollutants are generated after combustion and discharged with the tail gas, causing environmental pollution, so it is necessary to purify the blast furnace gas. In order to remove harmful substances such as sulfur, the existing technology sets organic sulfur hydrolysis before TRT to hydrolyze organic sulfur COS into hydrogen sulfide, and uses desulfurizers such as iron oxide to remove inorganic sulfur after TRT. In order to protect the hydrolysis catalyst, it is also necessary to set up dechlorination, deoxidation and other protective devices before the hydrolysis catalyst. The process is long and causes a large pressure loss before and after TRT, which affects power generation. At the same time, the use of protective devices increases the cost of desulfurization. In addition, dry bag dust removal is now widely used in blast furnace gas, but the temperature of blast furnace gas is generally high, ranging from 150 to 220°C, and may be higher up to 260°C. The temperature of blast furnace gas entering the bag cannot be too high to prevent the bag from burning. Therefore, water spraying is generally required to cool down the blast furnace gas before entering the bag dust removal, which will consume a lot of water, lose heat, and cause a decrease in TRT power generation. In summary, it is necessary to develop a new blast furnace gas desulfurization technology. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a blast furnace gas purification device and a process method thereof, which can achieve low-cost and high-efficiency purification while reducing TRT power generation losses.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A blast furnace gas purification device is provided, comprising a heat exchange unit, a washing unit, a desulfurization unit and a sulfur separation and recovery unit connected in sequence; wherein:

[0006] The outlet of the desulfurization unit for discharging desulfurized blast furnace gas is also connected to the inlet at the bottom of the heat exchange unit, and the desulfurized blast furnace gas discharged from the desulfurization unit is transported to the heat exchange unit for heat exchange with the blast furnace gas after gravity dust removal.

[0007] According to the above scheme, a regeneration unit is further provided between the desulfurization unit and the sulfur separation and recovery unit, for regenerating the desulfurizer in the desulfurization unit, and then entering the sulfur separation and recovery unit to recover sulfur.

[0008] Preferably, the regeneration unit is a tower reactor, a bubble reactor or a jet pump reactor.

[0009] According to the above scheme, the washing unit is a plate tower, a spray tower, a bubbling tower, a packed tower or a mixed form thereof.

[0010] According to the above scheme, the desulfurization unit is a plate tower, a spray tower, a bubbling tower, a packed tower or a mixed form thereof.

[0011] A process for purifying blast furnace gas using the blast furnace gas purification device is provided, comprising the following steps:

[0012] After gravity dust removal, the blast furnace gas enters the heat exchange unit and exchanges heat with the desulfurized blast furnace gas generated by the desulfurization unit. The cooled blast furnace gas enters the washing unit for washing and purification. The washed and purified blast furnace gas goes to the desulfurization unit for desulfurization. The desulfurizer set in the desulfurization unit converts the sulfur-containing substances in the blast furnace gas into sulfur to obtain desulfurized blast furnace gas; the desulfurized blast furnace gas goes to the heat exchange unit for heat exchange with the blast furnace gas from the gravity dust removal and recovers heat, and the heated desulfurized blast furnace gas goes to TRT for power generation; the desulfurizer containing sulfur in the desulfurization unit goes to the sulfur separation and recovery unit to recover sulfur, and the desulfurizer after oxidation regeneration goes to the desulfurization unit for reuse; wherein:

[0013] The desulfurizing agent is an aqueous solution containing transition metal ions, a complexing agent, an alkali, a stabilizer and an accelerator; wherein, by mass percentage, the transition metal ions are 0.01-5%, the alkali is 1-20%, the stabilizer is 1-20%, and the accelerator is 0.001-0.2%; the molar ratio of the complexing agent to the transition metal ions is 1.2-10:1; the accelerator is a zinc or cobalt complex of an organic substance, and the organic substance is 1,4,7-triazacyclononane, 1,4,7,10-tetraazacyclododecane, porphyrin or phthalocyanine.

[0014] According to the above scheme, the sulfur-containing substances in blast furnace gas include organic sulfur (COS), inorganic sulfur and the like.

[0015] According to the above scheme, the washing unit uses water or alkaline solution as washing liquid to remove dust and impurities such as fluorine and chlorine in blast furnace gas.

[0016] According to the above scheme, the oxidation regeneration process of the desulfurizer is as follows: if the blast furnace gas contains oxygen or air or oxygen-containing gas is added to the blast furnace gas, the oxygen content in the blast furnace gas is controlled at 0.01% to 2%, and the oxidation regeneration and desulfurization reaction of the desulfurizer are both carried out in the desulfurization unit; if the blast furnace gas does not contain oxygen or the oxygen content is too low and no additional air or oxygen-containing gas is added, the oxidation regeneration process of the desulfurizer is carried out in a separate regeneration unit, and the desulfurizer is regenerated by introducing air or oxygen-containing gas to react with the desulfurizer.

[0017] Preferably, when a regeneration unit is provided separately, the desulfurizer mixed with sulfur goes to the regeneration unit. In the regeneration unit, air is introduced from the bottom of the tower, and the desulfurizer flows down from the top of the tower, where it contacts with the oxygen in the air in countercurrent and undergoes an oxidation reaction, thereby oxidizing the transition metal ions in the desulfurizer to a high valence and restoring the oxidation capacity, thereby regenerating the desulfurizer. The regenerated desulfurizer goes to the sulfur separation unit.

[0018] According to the above scheme, the temperature of the blast furnace gas drops to 60-120°C after being cooled by the heat exchange unit; the temperature of the desulfurized blast furnace gas rises to 180-280°C after being heated by the heat exchange unit.

[0019] According to the above scheme, the temperature of blast furnace gas is further reduced to 50-90°C after being washed and purified in the washing unit.

[0020] According to the above scheme, the blast furnace gas after cooling by the heat exchange unit goes to the scrubbing unit, and the blast furnace gas is scrubbed with scrubbing liquid to reduce the dust content in the blast furnace gas to 10mg / m 3 Below, harmful impurities such as chlorine and fluorine in blast furnace gas are removed at the same time, so that the chlorine and fluorine content in blast furnace gas is less than 5ppm.

[0021] According to the above scheme, the washing liquid is discharged from the bottom of the washing unit, the dust-containing washing liquid is filtered and separated, a part of the washing liquid after the solid is separated is used for desalination, and the remaining part is supplemented with washing liquid for recycling.

[0022] According to the above scheme, the desulfurization reaction temperature in the desulfurization unit is 40-90°C.

[0023] According to the above scheme, the transition metal ion is one or more of iron ion, manganese ion, and copper ion; preferably, the transition metal ion is iron ion, a combination of iron ion and manganese ion, a combination of iron ion and copper ion, or a combination of iron ion, manganese ion and copper ion.

[0024] According to the above scheme, the complexing agent is one or more mixtures of EDTA, salicylic acid, polyaspartic acid, iminodisuccinic acid, diethylenetriaminepentacarboxylic acid, nitrilotriacetic acid, ethylenediaminetetraethylphosphonic acid, diethylenetriaminepentamethylphosphonic acid, etc. and their salts.

[0025] According to the above scheme, the base is one or more mixtures of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, ethylenediamine, ethanolamine, diethanolamine, triethanolamine, diglycolamine, piperazine, hydroxyethylpiperazine, aminoethylpiperazine, pyrazine, 2-aminopyrazine, pyridazine, 3-aminopyridazine, and isophoronediamine.

[0026] According to the above scheme, the stabilizer is a water-soluble polyol; preferably, it is a mixture of one or more of ethylene glycol, propylene glycol, butylene glycol, glycerol, polyethylene glycol, and glucose.

[0027] According to the above scheme, the accelerator is prepared by adding 1,4,7-triazacyclononane, 1,4,7,10-tetraazacyclododecane, porphyrin or phthalocyanine to a zinc hydroxide or cobalt hydroxide suspension until the zinc hydroxide or cobalt hydroxide is completely dissolved.

[0028] According to the above scheme, the desulfurizer also contains a sulfur dispersant and a corrosion inhibitor.

[0029] According to the above scheme, in the sulfur separation and recovery unit, sulfur is separated by sedimentation, filtration or centrifugation.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. The present invention provides a blast furnace gas purification device, which reduces the temperature of the imported blast furnace gas by setting a heat exchange unit, making wet dust removal, purification and desulfurization before TRT possible, and reducing the amount of blast furnace gas cooling water; at the same time, heat exchange increases the temperature of the blast furnace gas at the outlet of the purification system, recovers heat, and increases TRT power generation.

[0032] 2. The present invention performs wet dust removal, which saves bag replacement costs compared to dry bag dust removal, and avoids the problem of bag burning caused by excessively high blast furnace coal temperature.

[0033] 3. The present invention provides a blast furnace gas purification process. Through a heat exchange unit, on the one hand, the temperature of the inlet blast furnace gas is reduced to make it suitable for wet processing. Through wet dust removal, purification and desulfurization, the desulfurizer directly converts the sulfur-containing substances into sulfur to make it a resource, and the separation is simple, no additional sulfur-containing solid waste is generated, and the desulfurizer can be recycled; on the other hand, the heat is recovered and the temperature of the outlet blast furnace gas is increased, thereby increasing the power generation of TRT; the entire purification process is short, the blast furnace gas temperature drop is highly matched with the process steps, the energy consumption is low, the system pressure drop is small, and the TRT generates more power. At the same time, the blast furnace gas after purification and desulfurization enters the TRT power generation more cleanly, avoiding corrosion of the power generation equipment and extending the service life of the equipment.

[0034] 4. The present invention carries out desulfurization before TRT. The blast furnace gas pressure before TRT is high, and the gas volume is compressed, so the residence time in the desulfurization unit is correspondingly long. In this way, less desulfurizer can be used to achieve the same reaction effect. Therefore, the amount of desulfurizer can be reduced while the reactor volume can be reduced, which significantly reduces the volume of the desulfurization equipment and reduces the equipment cost.

[0035] 5. Furthermore, the present invention can also adjust the oxygen content in the blast furnace gas so that the desulfurization and regeneration reactions can be completed simultaneously in the desulfurization unit, thereby reducing equipment and saving investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1A schematic diagram of a blast furnace gas desulfurization device provided in an embodiment of the present invention.

[0037] Figure 2 It is a schematic diagram of a blast furnace gas desulfurization device in which a regeneration device is separately provided in an embodiment of the present invention.

[0038] Among them: 1. heat exchange unit, 2. washing unit, 3. desulfurization unit, 4. regeneration unit, 5. sulfur separation unit. DETAILED DESCRIPTION

[0039] The following is combined with Figure 1 The present invention is further described, but it does not limit the protection scope of the present invention.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a blast furnace gas purification device, comprising a heat exchange unit, a washing unit, a desulfurization unit and a sulfur separation and recovery unit connected in sequence; wherein:

[0041] The outlet of the desulfurization unit for discharging desulfurized blast furnace gas is also connected to the inlet at the bottom of the heat exchange unit, and the desulfurized blast furnace gas discharged from the desulfurization unit is transported to the heat exchange unit for heat exchange with the blast furnace gas after gravity dust removal.

[0042] In one embodiment, Figure 2 As shown, a regeneration unit is also provided between the desulfurization unit and the sulfur separation and recovery unit, for regenerating the desulfurizer in the desulfurization unit, and then entering the sulfur separation and recovery unit to recover sulfur. In a preferred embodiment, the regeneration unit is a tower reactor, a bubbling reactor or a jet pump reactor.

[0043] In one embodiment, the washing unit is a plate tower, a spray tower, a bubbling tower, a packed tower or a mixture thereof.

[0044] In one embodiment, the desulfurization unit is a plate tower, a spray tower, a bubbling tower, a packed tower or a mixture thereof.

[0045] The embodiment of the present invention also provides a process for purifying blast furnace gas using the blast furnace gas purification device, comprising the following steps:

[0046] After gravity dust removal, the blast furnace gas enters the heat exchange unit and exchanges heat with the desulfurized blast furnace gas generated by the desulfurization unit. The cooled blast furnace gas enters the washing unit for washing and purification. The washed and purified blast furnace gas goes to the desulfurization unit for desulfurization. The desulfurizer provided in the desulfurization unit converts the sulfur-containing substances in the blast furnace gas into sulfur to obtain desulfurized blast furnace gas. The desulfurized blast furnace gas goes to the heat exchange unit for heat exchange with the blast furnace gas from the gravity dust removal and recovers heat. The heated desulfurized blast furnace gas goes to TRT for power generation. The desulfurizer containing sulfur in the desulfurization unit goes to the sulfur separation and recovery unit to recover sulfur. The desulfurizer after oxidation regeneration goes to the desulfurization unit for reuse. Among them:

[0047] The desulfurizing agent is an aqueous solution containing transition metal ions, a complexing agent, an alkali, a stabilizer and an accelerator; wherein, by mass percentage, the transition metal ions are 0.01-5%, the alkali is 1-20%, the stabilizer is 1-20%, and the accelerator is 0.001-0.2%; the molar ratio of the complexing agent to the transition metal ions is 1.2-10:1; the accelerator is a zinc or cobalt complex of an organic substance, and the organic substance is 1,4,7-triazacyclononane, 1,4,7,10-tetraazacyclododecane, porphyrin or phthalocyanine.

[0048] In one embodiment, the sulfur-containing substances in the blast furnace gas are organic sulfur and inorganic sulfur.

[0049] In one embodiment, the washing unit uses water or alkaline solution as washing liquid to remove dust and impurities such as fluorine and chlorine in blast furnace gas.

[0050] In one embodiment, the oxidation regeneration process of the desulfurizer is as follows: if the blast furnace gas contains oxygen or air or oxygen-containing gas is added to the blast furnace gas, the oxygen content in the blast furnace gas is controlled at 0.01% to 2%, and the oxidation regeneration and desulfurization reaction of the desulfurizer are both carried out in the desulfurization unit; if the blast furnace gas does not contain oxygen or the oxygen content is too low and no additional air or oxygen-containing gas is added, the oxidation regeneration process of the desulfurizer is carried out in a separate regeneration unit, and the desulfurizer is regenerated by introducing air or oxygen-containing gas to react with the desulfurizer.

[0051] In a preferred embodiment, when a regeneration unit is provided separately, the desulfurizer mixed with sulfur goes to the regeneration unit. In the regeneration unit, air is introduced from the bottom of the tower, and the desulfurizer flows down from the top of the tower, where it comes into countercurrent contact with the oxygen in the air and undergoes an oxidation reaction, thereby oxidizing the transition metal ions in the desulfurizer to a high valence and restoring the oxidation capacity, thereby regenerating the desulfurizer. The regenerated desulfurizer goes to the sulfur separation unit.

[0052] In one embodiment, after the blast furnace gas is cooled by the heat exchange unit, the temperature drops to 60-120°C; after the desulfurized blast furnace gas is heated by the heat exchange unit, the temperature rises to 180-280°C.

[0053] In one embodiment, the temperature of the blast furnace gas is further reduced to 50-90° C. after being washed and purified in the washing unit.

[0054] In one embodiment, the blast furnace gas after being cooled by the heat exchange unit is sent to the scrubbing unit, where the blast furnace gas is scrubbed with a scrubbing liquid to reduce the dust content in the blast furnace gas to 10 mg / m 3 Below, harmful impurities such as chlorine and fluorine in blast furnace gas are removed at the same time, so that the chlorine and fluorine content in blast furnace gas is less than 5ppm.

[0055] In one embodiment, the washing liquid is discharged from the bottom of the washing unit, the dust-containing washing liquid is filtered and separated, a part of the washing liquid after the solid is separated is used for desalination, and the remaining part is supplemented with washing liquid for recycling.

[0056] In one of the embodiments, the desulfurization reaction temperature in the desulfurization unit is 40-90°C.

[0057] In one embodiment, the transition metal ion is one or more of iron ion, manganese ion, and copper ion, and preferably the transition metal ion is iron ion, a combination of iron ion and manganese ion, a combination of iron ion and copper ion, or a combination of iron ion, manganese ion and copper ion. The complexing agent is one or more mixtures of EDTA, salicylic acid, polyaspartic acid, iminodisuccinic acid, diethylenetriaminepentacarboxylic acid, nitrilotriacetic acid, ethylenediaminetetraethylphosphonic acid, diethylenetriaminepentamethylphosphonic acid, and their salts. The base is one or more mixtures of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, ethylenediamine, ethanolamine, diethanolamine, triethanolamine, diglycolamine, piperazine, hydroxyethylpiperazine, aminoethylpiperazine, pyrazine, 2-aminopyrazine, pyridazine, 3-aminopyridazine, and isophoronediamine. The stabilizer is a polyol soluble in water; preferably one or more mixtures of ethylene glycol, propylene glycol, butanediol, glycerol, polyethylene glycol, and glucose.

[0058] In one embodiment, the promoter is prepared by adding 1,4,7-triazacyclononane, 1,4,7,10-tetraazacyclododecane, porphyrin or phthalocyanine to a zinc hydroxide or cobalt hydroxide suspension until the zinc hydroxide or cobalt hydroxide is completely dissolved.

[0059] In one embodiment, the desulfurizer also contains a sulfur dispersant and a corrosion inhibitor.

[0060] In one embodiment, in the sulfur separation and recovery unit, sulfur is separated by sedimentation, filtration or centrifugation.

[0061] The following are specific embodiments.

[0062] The preparation methods of the desulfurizers 1-4 used in the specific examples are as follows:

[0063] Desulfurizer 1

[0064] Take 2.8 grams of FeSO4.7H2O and dissolve it in 100 ml of water. Then add 4.4 grams of chelating agent EDTA to the FeSO4 solution, and then add 5 grams of base NaCO3. After stirring the solution evenly, add 10 grams of stabilizer ethylene glycol to obtain solution 1.

[0065] Take 0.1 g of zinc hydroxide and add it to 25 ml of water, stir it into a suspension, then take 0.13 g of 1,4,7-triazacyclononane and add it to the zinc hydroxide suspension, stir for 30 minutes to completely dissolve the zinc hydroxide, and obtain solution 2.

[0066] Pour solution 2 into solution 1 and stir evenly to obtain desulfurizer 1.

[0067] Desulfurizer 2

[0068] Take 2.1 grams of FeSO4.7H2O and 0.423 grams of MnSO4.H2O and dissolve them in 100 ml of water. Then add 7.4 grams of complexing agent iminodisuccinic acid to the FeSO4-MnSO4 mixed solution, and then add 6 grams of base NaOH. After stirring, add 3 grams of stabilizer propylene glycol to the solution to obtain solution 1.

[0069] 0.01 g of cobalt hydroxide was added to 10 ml of water and stirred to form a suspension. Then 0.02 g of 1,4,7,10-tetraazacyclododecane was added to the cobalt hydroxide suspension and stirred for 40 min to completely dissolve the cobalt hydroxide to obtain Solution 2.

[0070] Pour solution 2 into solution 1 and stir evenly to obtain desulfurizer 2.

[0071] Desulfurizer 3

[0072] Take 0.28 g of FeSO4.7H2O and dissolve it in 100 ml of water. Then add 1.5 g of ethylenediaminetetraethylphosphonic acid, a complexing agent, to the FeSO4 solution, and then add 10 g of isophoronediamine, a base, and 5 g of aminoethylpiperazine. After stirring, add 10 g of polyethylene glycol 300, a stabilizer, and 2 g of glucose to the solution to obtain solution 1.

[0073] Take 0.02 g of zinc hydroxide and add it to 20 ml of water, stir it into a suspension, then take 0.04 g of 1,4,7,10-tetraazacyclododecane and add it to the zinc hydroxide suspension, stir for 30 minutes to completely dissolve the zinc hydroxide, and obtain solution 2.

[0074] Pour solution 2 into solution 1 and stir evenly to obtain desulfurizer 3.

[0075] Desulfurizer 4

[0076] Take 0.243 g of FeCl3.6H2O and 0.1 g of Cu(NO3)2.H2O and dissolve them in 100 ml of water. Then add 1.8 g of diethylenetriamine penta(methylenephosphonic acid) as a complexing agent to the FeCl3-Cu(NO3)2 solution, then add 5.5 g of potassium hydroxide and 1 g of 3-aminopyridazine as alkali. After stirring, add 8 g of butanediol and 2 g of glucose as stabilizers to the solution to obtain solution 1.

[0077] Take 0.04 g of zinc hydroxide and add it to 20 ml of water, stir it into a suspension, then take 0.08 g of 1,4,7,10-tetraazacyclododecane and add it to the zinc hydroxide suspension, stir for 30 minutes to completely dissolve the zinc hydroxide, and obtain solution 2.

[0078] Pour solution 2 into solution 1 and stir evenly to obtain desulfurizer 4.

[0079] Take 100 ml of the above desulfurizer and load it into the bubbling bed reactor. The gas source without carbon dioxide and the gas source containing carbon dioxide are introduced respectively. The gas is introduced into the bubbling bed reactor at 250 ml / min. After reacting for 6 hours, the inlet and outlet are analyzed by gas chromatography. The evaluation results are shown in Table 1:

[0080] Example 1

[0081] The 245°C blast furnace gas from the blast furnace enters the heat exchange unit after gravity dust removal, and exchanges heat with the desulfurized blast furnace gas in the heat exchange unit (1), and the temperature drops to 100°C.

[0082] The cooled blast furnace gas is sent to the scrubbing unit, where it is scrubbed with alkali solution to reduce the dust content in the blast furnace gas to 10 mg / m 3 At the same time, harmful impurities such as chlorine and fluorine in the blast furnace gas are removed, so that the chlorine and fluorine content in the blast furnace gas is less than 5 ppm, and the temperature of the blast furnace gas after washing and purification is further reduced to 80° C. The washing liquid is discharged from the bottom of the washing unit (2), and the dust-containing washing liquid is filtered and separated. A part of the washing liquid after the solid is separated is used for desalination, and the remaining part is supplemented with alkali solution for recycling.

[0083] A small amount of oxygen or air is added to the washed and purified blast furnace gas to control the oxygen content in the blast furnace gas to 0.55%, and then the gas is sent to the desulfurization unit. In the desulfurization reactor of the desulfurization unit (3), the blast furnace gas is fully contacted with the desulfurizer for reaction; organic sulfur COS and hydrogen sulfide are converted into sulfur at about 75°C, and at the same time, the oxygen in the blast furnace gas oxidizes the transition metal ions in the desulfurizer to a high valence and restores the oxidation capacity, and desulfurization and regeneration are completed synchronously in the desulfurization unit (3).

[0084] The desulfurizing agent after the reaction is sent to the sulfur separation and recovery unit (5), and sulfur is obtained by filtration and separation, and the filtrate is sent to the desulfurization reactor of the desulfurization unit (3) for recycling. The sulfur filter cake is washed and sulfur is melted to obtain recovered sulfur.

[0085] The purified gas goes to the heat exchange unit (1), exchanges heat with the blast furnace gas after gravity dust removal in the heat exchange unit (1), and the temperature is restored to 210° C., and then goes to the TRT power generation device.

[0086] A simulated blast furnace gas desulfurization experiment was carried out in the laboratory. When the flow rate of the simulated blast furnace gas flow was 250 ml / min, the desulfurizer was 100 ml, and the desulfurizer was selected from any one of desulfurizers 1-4. The specific desulfurization conditions and desulfurization effects are shown in Table 1 below.

[0087] Table 1

[0088]

[0089] The present invention uses specific examples to elaborate the inventive concept in detail, and the description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, any obvious modifications, equivalent substitutions or other improvements made without departing from the inventive concept should be included in the protection scope of the present invention.

Claims

1. A blast furnace gas purification device, characterized in that: It comprises a heat exchange unit, a washing unit, a desulfurization unit and a sulfur separation and recovery unit connected in sequence; wherein: The outlet of the desulfurization unit for discharging desulfurized blast furnace gas is also connected to the inlet at the bottom of the heat exchange unit, and the desulfurized blast furnace gas discharged from the desulfurization unit is transported to the heat exchange unit for heat exchange with the blast furnace gas after gravity dust removal.

2. The blast furnace gas purification device according to claim 1, characterized in that: A regeneration unit is also provided between the desulfurization unit and the sulfur separation and recovery unit, for regenerating the desulfurizer in the desulfurization unit and then entering the sulfur separation and recovery unit to recover sulfur.

3. The blast furnace gas purification device according to claim 1, characterized in that: The desulfurization unit is a plate tower, a spray tower, a bubbling tower, a packed tower or a mixed form thereof.

4. A process for purifying blast furnace gas using the device according to any one of claims 1 to 3, characterized in that: The following steps are involved: The blast furnace gas enters the heat exchange unit after gravity dust removal, and heat exchanges with the desulfurized blast furnace gas generated by the desulfurization unit. The cooled blast furnace gas enters the washing unit for washing and purification. The blast furnace gas after washing and purification is desulfurized in the desulfurization unit. The desulfurizer provided in the desulfurization unit converts the sulfur-containing substances in the blast furnace gas into sulfur to obtain desulfurized blast furnace gas; the desulfurized blast furnace gas heat exchanges with the blast furnace gas after gravity dust removal to heat up and recover heat, and the heated desulfurized blast furnace gas is used for TRT power generation; the desulfurizer containing sulfur in the desulfurization unit is desulfurized and separated and recovered by the recovery unit to recover sulfur, and the desulfurizer after oxidation regeneration is reused in the desulfurization unit; wherein: The desulfurizing agent is an aqueous solution containing transition metal ions, a complexing agent, an alkali, a stabilizer and an accelerator; wherein, by mass percentage, the transition metal ions are 0.01-5%, the alkali is 1-20%, the stabilizer is 1-20%, and the accelerator is 0.001-0.2%; the molar ratio of the complexing agent to the transition metal ions is 1.2-10:1; the accelerator is a zinc or cobalt complex of an organic substance, and the organic substance is 1,4,7-triazacyclononane, 1,4,7,10-tetraazacyclododecane, porphyrin or phthalocyanine.

5. The process according to claim 4, characterized in that: The washing unit uses water or alkaline solution as washing liquid to remove dust and fluorine and chlorine impurities in blast furnace gas.

6. The process according to claim 4, characterized in that: The oxidation regeneration process of the desulfurizer is as follows: if the blast furnace gas contains oxygen or air or oxygen-containing gas is added to the blast furnace gas, the oxygen content in the blast furnace gas is controlled to be between 0.01% and 2%, and the oxidation regeneration and desulfurization reaction of the desulfurizer are both carried out in the desulfurization unit; if the blast furnace gas does not contain oxygen or the oxygen content is too low and no additional air or oxygen-containing gas is added, the oxidation regeneration process of the desulfurizer is carried out in a separate regeneration unit, and the desulfurizer is regenerated by introducing air or oxygen-containing gas to react with the desulfurizer.

7. The process according to claim 6, characterized in that: When a regeneration unit is provided separately, the desulfurizer mixed with sulfur goes to the regeneration unit. In the regeneration unit, air is introduced from the bottom of the tower, and the desulfurizer flows down from the top of the tower, where it contacts with the oxygen in the air in countercurrent and undergoes an oxidation reaction, thereby oxidizing the transition metal ions in the desulfurizer to a high valence and restoring the oxidation capacity, thereby regenerating the desulfurizer. The regenerated desulfurizer goes to the sulfur separation unit.

8. The process according to claim 4, characterized in that: The blast furnace gas from gravity dust removal is cooled by heat exchange unit, and its temperature drops to 60-120°C; the desulfurized blast furnace gas is heated by heat exchange unit, and its temperature rises to 180-280°C; the blast furnace gas is further cooled to 50-90°C by washing and purification in the washing unit; the desulfurization reaction temperature in the desulfurization unit is 40-90°C.

9. The process according to claim 4, characterized in that: The blast furnace gas after cooling by the heat exchange unit goes to the scrubbing unit, where the blast furnace gas is scrubbed with scrubbing liquid to reduce the dust content in the blast furnace gas to 10 mg / m 3 Below, the harmful impurities of chlorine and fluorine in the blast furnace gas are removed at the same time, so that the chlorine and fluorine content in the blast furnace gas is less than 5ppm.

10. The process according to claim 4, characterized in that: Desulfurizer: The transition metal ions are one or more of iron ions, manganese ions, and copper ions; The complexing agent is one or more mixtures of EDTA, salicylic acid, polyaspartic acid, iminodisuccinic acid, diethylenetriaminepentacarboxylic acid, nitrilotriacetic acid, ethylenediaminetetraethylphosphonic acid, diethylenetriaminepentamethylphosphonic acid, etc. and their salts; The stabilizer is a polyol soluble in water; The accelerator is prepared by adding 1,4,7-triazacyclononane, 1,4,7,10-tetraazacyclododecane, porphyrin or phthalocyanine into a zinc hydroxide or cobalt hydroxide suspension until the zinc hydroxide or cobalt hydroxide is completely dissolved.

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