CN113684070A - Treatment process and device for low-concentration blast furnace gas containing inorganic sulfur - Google Patents

Abstract

The invention relates to the field of chemical production, in particular to a treatment process and a treatment device for blast furnace gas containing inorganic sulfur. The method comprises the steps of adsorbing blast furnace gas by activated carbon, and adding a hydrolytic agent to convert organic sulfur into hydrogen sulfide; entering a TRT device to recover energy; then enters a spray tower C to absorb SO by NaHS solution₂Carrying out full reaction; then enters a spray tower D to be treated by a desulfurizer, and a device formed by the connection of the desulfurizer and the desulfurizer. The invention has the advantages that the desulfurizer is recycled, the regeneration process of the desulfurizer is simple, the energy consumption is low, the reaction condition is mild, the reaction process is a liquid phase reaction process at normal temperature and normal pressure, and the desulfurization efficiency is high; the service life of the process equipment and the pipeline is long, and the maintenance cost is low.

Description

Treatment process and device for low-concentration blast furnace gas containing inorganic sulfur

Technical Field

The invention relates to the field of chemical production, in particular to a treatment process and a treatment device for blast furnace gas containing inorganic sulfur.

Background

The blast furnace gas is a byproduct generated in the blast furnace ironmaking process in the ironmaking procedure of iron and steel enterprises, and comprises the main components of CO and CO₂、N₂、H₂、CH₄Etc., wherein the combustible component CO content is about 20-25%, and H₂、CH₄Is very small in content, CO₂、N₂The content of the heat value is respectively 15-22% and 55%, and the heat value is about 3500KJ/m³. Blast furnace gas is mainly used as fuel for iron-making sintering, pelletizing, blast furnace hot blast furnaces, steel rolling heating furnaces, heat treatment furnaces, self-contained thermal power plant gas boilers and the like in iron and steel enterprises. At present, gas-fired boiler equipment is in accordance with the emission Standard of boiler atmospheric pollutants, SO₂Emission limit of 50mg/Nm 3; according to the emission Standard of atmospheric pollutants for thermal Power plants, the atmospheric pollutants SO of gas boilers₂Emission limit of 35mg/Nm³(ii) a 22.4.2019, the ecological environment department issued an opinion on the implementation of ultra-low emission in the steel industry, strict requirements are put forward on ultra-low emission indexes of steel enterprises, major areas for air pollution control such as Jingjin Ji and peripheral areas, Yangqi area, Fenwei plain and the like are advanced first, and the limit of emission of sulfur dioxide of sintered and self-contained power plants is 35mg/Nm³Iron-smelting hot-blast stove and steel-rolling heat treatment furnace SO₂Emission limit 50mg/Nm³The desulfurization treatment of blast furnace gas is the inevitable requirement for ensuring the subsequent standard discharge and is also the requirement of the current environmental protection policy.

The blast furnace has large gas quantity and dispersed end users, and the gas contains H₂S contains a certain content of organic sulfur, hydrogen cyanide, chlorine, fluorine, dust and other impurities, such as SO is removed after coal gas is combusted₂The process needs to be added with a plurality of sets of SO removal₂The device is dispersed and the investment is largeAnd the management cost is high, and the whole process of pipeline equipment has serious potential safety hazard in the aspect of corrosion. The prior patents 201310583623.1 and 201410026037.1 disclose that the concentration of H is high₂S treatment has advantages in that effective effects cannot be achieved at low concentrations, and cost is high.

According to the practical situation of blast furnace gas desulfurization, a set of blast furnace gas is developed to be desulfurized in a centralized way at the source, and the desulfurized blast furnace gas meets the requirement of H₂The S content is controlled to be 20mg/Nm³The total sulfur content was controlled to 28mg/Nm³SO that 35mg/Nm3 of SO is satisfied after the blast furnace gas is combusted in the self-contained power plant₂Discharge standard, hot blast stove and steel rolling heating furnace 50mg/Nm³SO of (A)₂And (4) emission standard. The scheme can better realize the environmental protection benefit, the social benefit and the economic benefit of the iron and steel enterprises.

The prior blast furnace gas desulfurization technology introduces:

post-desulfurization-conventional desulfurization protocol: the blast furnace gas of the iron and steel enterprise has more users and complex and changeable working conditions, and the SO removal after the adoption is carried out according to the technical characteristics₂The traditional flue gas system desulfurization process (lime gypsum method, wet method, semi-dry method, dry method and the like) does not meet the desulfurization requirements of the current steel enterprises, and adopts a dispersive desulfurization mode, so that the investment is relatively large and the occupied area is large.

Pre-desulfurization-existing desulfurization scheme: the blast furnace gas treatment process flow is shown in the attached figure 1.

Aiming at the technology of processing the sulfur component in the blast furnace gas, four steps are needed to be adopted for completion, and the method specifically comprises the following steps:

1) a-1, blast furnace gas pretreatment in the tower: treating blast furnace gas (active carbon adsorbing Cl, F, etc.)

2) The conversion of carbonyl sulfide into inorganic sulfur is completed in the A-2 tower: COS-H2S

3) And (3) carrying out coarse removal of inorganic sulfur by the tower B: h₂S+HCL

4) C, fine removal of inorganic sulfur by a tower C: h₂S+HCL+H₂O

Wherein the conversion process of organic sulfur is mainly in the A-1 and A-2 towers, and the removal process of inorganic sulfur is mainly in the B, C tower, and finallyEnsuring SO after combustion of blast furnace gas₂The emission index of (1). The gas pipeline in the red line range of the tower A adopts a stainless steel composite pipeline.

The organic sulfur conversion tower adopts a fixed bed, needs manual replacement, is replaced once a year or so generally according to the condition of a blast furnace for about 48 hours, has the non-toxic and harmless characteristic of a reactant, and is mainly composed of modified activated carbon, thereby being not hazardous to waste.

Early-stage source desulfurization, and the desulfurized blast furnace gas meets SO of all subsequent users₂Emission standard, desulfurization process centralization, and equipment and engineering are in one process. The equipment resistance is small, the operation is stable, and the desulfurization efficiency can reach 90-95%. And the spray desulfurization solution (NaOH solution) of the B, C tower has rich resources, low price and low operating cost. The desulfurization solution from the tower body passes through a purification treatment system, is pressurized by a pump and then is conveyed to the top of an alkali spraying tower to be in countercurrent contact with blast furnace gas from bottom to top from the bottom of the tower, and the desulfurization solution is recycled.

Na is generated after the NaOH solution is desulfurized₂Adding water purifying agent (FeSO) into the S solution₄) FeS sediment and Na2SO4 solution are produced through reaction, and the FeS sediment is matched with an inclined tube sedimentation tank, a flocculation and coagulation mixer, a sludge tank, a sludge screw pump, a plate-and-frame filter press and a dosing device and then enters a sintering machine to be used as a sintering raw material. The Na2SO4 solution enters a newly-built water treatment center for independent desalination, BOD and COD removal treatment and finally enters a wastewater treatment system of a steel enterprise.

The advantages are that:

1) the combination of the dry conversion and the wet desulfurization processes not only realizes the high efficiency and stability of the organic sulfur conversion and inorganic sulfur removal processes, but also fully exerts the technical and economic advantages of the respective processes for the organic sulfur and inorganic sulfur removal;

2) desulfurizing by chemical absorption method, and wet desulfurizing to obtain tail gas H₂The S content can be reduced to 20mg/Nm³The total sulfur content was controlled to 28mg/Nm³The following;

3) the process device occupies small area;

4) the device has high operation stability and reliability;

5) the wet desulphurization adopts a packed tower absorption technology, so that the desulphurization efficiency is high;

6) the service life of the process equipment and the pipeline is long, and the maintenance cost is low.

The disadvantages are as follows:

and the FeS sediment enters the sintering machine again, the S load of the sintering machine is increased, and finally the sintering desulfurization pressure is increased. Product Na₂SO₄The solution treatment capacity is large, and the wastewater treatment process is long. The treatment cost of iron per ton reaches 10-15 yuan per ton, and the operation cost is high.

Disclosure of Invention

Aiming at the defects in the prior art, the problems of high cost, secondary pollution and the like in the actual operation process, the invention provides a new treatment scheme.

The invention is realized by the following technical scheme:

a process for treating low-concentration blast furnace gas containing inorganic sulfur is characterized by comprising the following steps:

(1) adsorbing blast furnace gas by activated carbon to remove chlorine and fluorine gases in the blast furnace gas; before the activated carbon adsorption, the blast furnace gas is dedusted by a dry method, so that the protection of equipment is facilitated;

(2) adding a hydrolytic agent into the adsorbed blast furnace gas in a desulfurization device to convert organic sulfur in the blast furnace gas into hydrogen sulfide;

(3) the blast furnace gas converted in the step (2) enters a TRT device to recover energy;

(4) blast furnace gas coming out of the TRT enters a spray tower C, the upper part of the spray tower C is sprayed with NaHS solution and SO in the blast furnace gas₂Carrying out full reaction;

the blast furnace gas from the spray tower C enters a spray tower D; the spray liquid from the spray tower C enters a NaHS reflux pool;

(5) after entering the spray tower D, the blast furnace gas reacts with a desulfurizer sprayed from the upper part of the spray tower D; discharging the blast furnace gas after treatment through a gas pipeline; the sprayed desulfurizer enters a desulfurizer regeneration tank; the desulfurizing agent is Fe-containing³⁺KOH solution of chelating agent.

Preferably, the NaHS solution in the NaHS reflux pool in the step (4) of the treatment process of the low-concentration blast furnace gas containing inorganic sulfur is divided into two paths, and a small amount of high-concentration NaHS solution is discharged from the NaHS reflux pool; and the other path of NaHS solution reflows to the upper part of the spray tower C to react with the blast furnace gas. The high concentration NaHS solution in the step (4) is preferably a saturated NaHS solution.

Preferably, the desulfurizer regeneration tank in the step (5) of the method for treating the blast furnace gas with low concentration containing inorganic sulfur is divided into an absorption zone, an oxidation zone and a degassing zone; the middle desulfurizer is subjected to oxidation reaction, and the absorbed spray liquid firstly enters an absorption area and is rich in hydrogen sulfide; the desulfurizer flowing out of the spray tower D enters an absorption area firstly, then flows into an oxidation area from the absorption area, and is oxidized by air to complete the generation of elemental sulfur and Fe³⁺Regenerating the chelating agent; then the desulfurizing agent flows into a degassing zone from the oxidation zone, and then is conveyed to the upper part of a spray tower D by a conveying pump for absorbing H₂S。

Preferably, the Fe-containing blast furnace gas having a low concentration of one kind of inorganic sulfur is treated in the step (5)³⁺The pH value of the KOH solution of the chelating agent is controlled between 8 and 9.

Preferably, in the step (5) of the method for treating low-concentration blast furnace gas containing inorganic sulfur, a high-concentration waste liquid discharge port is further provided in the desulfurizing agent regeneration tank, and the high-concentration waste liquid is discharged from the system for treatment.

Preferably, the Fe-containing blast furnace gas of step (5) of the method for treating a low-concentration blast furnace gas containing inorganic sulfur is³⁺The chelating agent is HEDP, EDTMPS, DTPMPA, EDDHA, STPP, NTA, Na₃NTA、HEDTA、Na₃HEDTA、Na₄At least one of EDTA, sodium gluconate, sodium metasilicate and potassium tartrate.

The treatment device of the blast furnace gas containing inorganic sulfur with low concentration is characterized in that a blast furnace gas pipeline is connected with an inlet of a spray tower C, and the inlet of the spray tower C is positioned at the lower part of the spray tower C; the upper part of the spray tower C is connected with an NaHS solution inlet pipe and a blast furnace gas outlet connecting pipe; the lower part of the spray tower C is also provided with a NaHS solution outlet;

the discharging port of the NaHS solution is connected with the NaHS reflux pool; the outlet of the NaHS reflux tank is divided into two paths, wherein one path is used for discharging high-concentration waste liquid, and the other path is connected to a NaHS solution inlet pipe at the upper part of the spray tower C through a pump;

a blast furnace gas outlet connecting pipe at the upper part of the spray tower C is connected to an inlet of the spray tower D, and the inlet of the spray tower D is positioned at the lower part of the spray tower D; the lower part of the inlet of the spray tower D is also provided with a desulfurizer discharging port which is connected with a desulfurizer regeneration tank; the upper part of the spray tower D is also provided with a desulfurizer inlet and a blast furnace gas outlet, and the blast furnace gas outlet is connected with a gas pipeline and conveyed outwards; the outlet of the desulfurizer regeneration tank is divided into two paths, one path is used for discharging high-concentration desulfurizer solution, and the other path is connected to a desulfurizer inlet at the upper part of the spray tower D through a pump; the bottom of the desulfurizer regeneration tank is also connected with a sulfur simple substance suction outlet.

Preferably, in the above-described apparatus for treating low-concentration inorganic sulfur-containing blast furnace gas, the desulfurizing agent regeneration tank is divided into at least an absorption zone, an oxidation zone and a degassing zone in this order. The desulfurization device is divided into two devices which are connected in series, and the effect of better treating materials can be achieved.

In the application, aiming at the sulfur component treatment technology in blast furnace gas,

c tower for SO₂And (3) transformation: SO (SO)₂(l)+2HS^-+H₂O→SO₃ ^2-+2H₂S(g)

And D, carrying out coarse removal of inorganic sulfur by a tower D: h₂S+HCL，S^2-(l)+2Fe³⁺→S+2Fe²⁺

The regeneration tank carries out the regeneration of the desulfurizer and the removal of the simple substance S: 1/2O₂(g)+H₂O+2Fe²⁺→2OH^-+2Fe³⁺

Organic sulfur hydrolysis-SO of blast furnace gas source₂The technical characteristics and the principle of the conversion-cycle desulfurization process flow are explained as follows:

chelating agent and catalyst:

in aqueous proportioning solution, ferrous ion (Fe)²⁺) And ferric ion (Fe)³⁺) All can not be stabilizedThere is, generally, a readily formed precipitate of iron hydroxide or iron sulfide by the reaction:

Fe³⁺+3OH^-→Fe(OH)₃(s)

Fe²⁺+S^2-→FeS(s)

in order to prevent the generation of the precipitate, the process system adopts a unique chelating agent, so that iron in the water proportioning liquid can keep a stable ionic state in a wider pH value range. A chelating agent is an organic compound that encapsulates a metal ion in a claw-like structure, allowing the metal ion to form a chemical bond with two or more non-metal ions.

CO in coal gas₂Influence and technical scheme:

the acid tail gas usually contains a certain amount of carbon dioxide (CO)₂) The gas, carbon dioxide is an acidic gas, and can generate a side reaction with water to electrolyze free H +, so that the pH value of the desulfurization medium is reduced. In particular, as the partial pressure increases, the side reactions that lower the pH increase. Carbon dioxide is readily soluble in water and forms bicarbonate (HCO)₃ ^-) And Carbonates (CO)₃ ^2-) The reaction is as follows:

in order to stabilize the pH of the solution, an alkaline substance, such as potassium hydroxide, is added to the system, which reacts with carbon dioxide as follows:

after KOH is added, the solution is proportioned to form HCO₃-——CO₃ ^2-Buffer the equilibrium solution, then CO₂The sulfur-containing compound is not absorbed and no alkali is consumed, but a small amount of alkali is required to be added at random in normal production to control the pH value of the entire desulfurization solution in order to suppress side reactions and to replenish salt lost with sulfur cakes.

SO in coal gas₂Influence and technical scheme:

SO in tail gas₂Is an important operating parameter, and the process is to add SO to the C column₂Absorption and conversion into H₂S gas is convenient for absorption in subsequent procedures, simplifies the pressure of the subsequent absorption procedures and can be obtained according to the actual SO in the blast furnace gas₂In this case, the amount of absorption conversion in the column is controlled to achieve the most economical overall process cost of desulfurization.

The desulfurization regeneration of the absorption liquid regeneration tank and the technical scheme are as follows:

the regeneration tank is divided into an absorption zone, an oxidation zone and a degassing zone by a partition plate. The absorption liquid rich in hydrogen sulfide overflows the clapboard and enters an oxidation zone, and the regeneration of the absorption liquid is completed under the action of air. And after the regeneration of the absorption liquid is finished, the absorption liquid enters a degassing area and is sent to a tower C by a pump for spraying, and the circulation is finished. Settling sulfur slurry containing 5-15 wt% of sulfur to the bottom of the oxidation pond, blowing air to avoid the sulfur from adhering to the pond wall, and finally pumping the sulfur slurry to a post-stage filter for treatment. The regeneration tank needs to be supplemented with a series of chemical agents and added through a metering pump, wherein the defoaming agent is added in batches and periodically in an air pressure injection mode.

The regeneration tank elemental sulfur removal technical scheme is as follows:

filtering the sulfur slurry by a filter to obtain a sulfur product with the water content of 35-45%.

Organic sulfur hydrolysis-SO of blast furnace gas source₂Analysis of the conversion-cycle desulfurization process:

wherein A, B the tower is mainly used for conversion of organic sulfur, and C the tower is SO₂The conversion process and the removal process of inorganic sulfur in the tower D are mainly adopted, SO after the blast furnace gas is combusted is finally ensured₂The emission index of (1). The gas pipeline in the red line range of the tower A adopts a stainless steel composite pipeline.

The organic sulfur hydrolysis and conversion tower adopts a fixed bed, needs to be replaced manually, the replacement time depends on the condition of a blast furnace, the replacement is generally carried out once every year for about 48 hours, the reactant has the characteristics of no toxicity and no harm, and the main component is modified activated carbon, which does not belong to hazardous waste.

Organic sulfur hydrolysis-SO of blast furnace gas source₂The conversion-cycle desulfurization process is adopted, and the desulfurized blast furnace gas meets the SO requirements of all subsequent users₂Emission standard, desulfurization process centralization, and equipment and engineering are in one process. Small resistance of equipment, stable operation, high desulfurizing efficiency up to 99%, and high desulfurizing efficiency₂The S concentration is less than 1 ppm. And the gas flow has large elasticity and can adapt to H in the feed gas₂The S concentration fluctuates greatly. The C tower NaHS is an industrial byproduct, has extremely low price and rich resources, and can be adjusted according to the working condition. D tower spray desulfurization liquid (containing Fe)³⁺Chelating agent lye) has rich resources, low price and low operating cost. The desulfurization solution from the tower body can be regenerated and recycled through a regeneration tank system, is pressurized through a pump and then is conveyed to the top of a spray tower C, and is in countercurrent contact with blast furnace gas from bottom to top from the bottom of the tower, the desulfurization solution is recycled, sulfur in the gas is finally removed as sulfur simple substances, and three wastes are not generated.

Organic sulfur hydrolysis-SO of blast furnace gas source₂The advantages of the conversion-cycle desulfurization process are summarized as follows:

Efficient

1) high hydrogen sulfide removal rate, one-step reaction removal rate of more than 99 percent, and treated tail gas H₂The S concentration is less than 1 ppm.

2) Wide application range, and can treat various kinds of H₂S、SO₂Gas, the selectivity is high. Especially for SO₂The blast furnace gas with higher or fluctuating content has rich treatment effect and process control means.

3) The acid gas flow has large elasticity and can adapt to H in the feed gas₂The S concentration fluctuates greatly.

Energy saving

1) The desulfurizer can be recycled.

2) The regeneration process of the desulfurizer is simple, the energy consumption is low, and the overall desulfurization cost is about 5-8 yuan per ton of iron.

3) The reaction condition is mild, and the reaction process is a liquid phase, normal temperature and normal pressure reaction process.

Environment-friendly

1) Except a small amount of waste liquid after desulfurization, no other three wastes are discharged.

2) High safety, no toxic chemical used, no H in sulfur product₂And (4) S gas.

Has the advantages that:

the combination of the dry conversion and the wet desulfurization processes not only realizes the high efficiency and stability of the organic sulfur conversion and inorganic sulfur removal processes, but also fully exerts the technical and economic advantages of the respective processes for the organic sulfur and inorganic sulfur removal; desulfurizing by chemical absorption method, and wet desulfurizing to obtain tail gas H₂The S content can be reduced to 20mg/Nm³The total sulfur content was controlled to 28mg/Nm³The following; the process device occupies small area; the device has high operation stability and reliability; the wet desulphurization adopts a packed tower absorption technology, so that the desulphurization efficiency is high; the service life of the process equipment and the pipeline is long, and the maintenance cost is low.

Low running cost

Because the absorption liquid is recycled, the product generates simple substance sulfur, no three wastes are generated, the power consumption is low, the operation cost is about 5-8 yuan/ton iron, and is 40 percent of the operation cost of the existing source desulfurization technology.

Low investment cost

The process of hydrolysis-circulation desulfurization treatment of the source organic sulfur is centralized and constructed, so the investment cost is low.

The process flow of the organosulfur hydrolysis-cycle desulfurization process of the source of blast furnace gas comprisesAfter dry dedusting, a tower A gas purification treatment is added before TRT to mainly purify Cl, F, S and other elements and contain activated carbon filler; b, hydrolyzing organic sulfur in the tower B, wherein the organic sulfur is hydrolyzed into hydrogen sulfide gas through a hydrolyzing agent; after TRT, add C tower, mainly make SO₂Conversion to H₂S, filling materials are contained, a transforming agent is NaHS solution, and NaHS is added according to actual production consumption; the tower C is followed by a tower D which is mainly a desulfurizer spray tower and contains filler, and the desulfurizer mainly contains alkali liquor (KOH) and Fe³⁺The chelating agent of (2) is mainly used for absorbing hydrogen sulfide.

Setting up SO separately₂A conversion process: according to the blast furnace gas SO₂The variation fluctuation range is large, a conversion process is added, and SO is added₂Conversion to H₂S, ensuring the subsequent H₂The S process is normally and efficiently operated, and the transforming agent has rich resources and extremely low price.

The regeneration pool desulfurization process has mild reaction conditions and is a liquid-phase, normal-temperature and normal-pressure reaction process. The process comprises the steps of refluxing a solution of hydrogen sulfide gas absorbed by the tower D to a regeneration tank, and reducing the hydrogen sulfide to an S simple substance in the regeneration tank through air aeration. The S simple substance is extracted by a pump through precipitation, and finally pressed into a sulfur cake containing 35-45% of water through a filter press, and a small amount of saturated salt-containing solution is discharged to blast furnace slag flushing water (10 tons/day). The absorption liquid is pumped to the D tower to circularly absorb the hydrogen sulfide. The absorption liquid is recycled, and in order to inhibit side reaction and supplement salt lost along with the sulfur cake, a small amount of alkali is required to be supplemented at random in normal production so as to control the overall pH value of the desulfurization solution.

The process is carried out in an alkaline environment with a pH value between 8 and 9.

The regeneration tank is divided into an absorption zone, an oxidation zone and a degassing zone by a partition plate. The absorption liquid rich in hydrogen sulfide overflows the clapboard and enters an oxidation zone, and the regeneration of the absorption liquid is completed under the action of air. And after the regeneration of the absorption liquid is finished, the absorption liquid enters a degassing area and is sent to a tower C by a pump for spraying, and the circulation is finished.

The removal rate of one-step reaction reaches more than 99 percent, and the treated tail gas H₂The S concentration is less than 1 ppm.

The desulfurization solution from the tower body can be regenerated and recycled through a regeneration tank system, is pressurized through a pump and then is conveyed to the top of a spray tower C, and is in countercurrent contact with blast furnace gas from bottom to top from the bottom of the tower, the desulfurization solution is recycled, sulfur in the gas is finally removed as sulfur simple substances, and three wastes are not generated.

C tower spray desulfurization liquid (containing Fe)³⁺Chelating agent lye) is an organic compound that encapsulates metal ions in a claw-like structure such that the metal ions form chemical bonds with two or more non-metal ions.

Drawings

FIG. 1 is a schematic diagram of the overall process flow used in the prior art

FIG. 2 is a schematic diagram of the overall process flow used in the present application

Detailed Description

The following detailed description of the invention is made with reference to the accompanying drawings:

example 1

As shown in the attached figure 2, blast furnace gas (the main components are CO and CO)₂、N₂、H₂、CH₄Etc., wherein the combustible component CO content is about 20-25%, and CO₂、N₂The contents of (A) and (B) are respectively 15-22% and 55%, and SO₂、H₂S, COS and hydroxysulfur, etc., and has a calorific value of about 3500KJ/m³) Removing chlorine and fluorine gases in the blast furnace gas by activated carbon adsorption; adding a hydrolytic agent into the adsorbed blast furnace gas in a desulfurization device to convert organic sulfur in the blast furnace gas into hydrogen sulfide; the hydrolytic agent is MTCOMS-01 type COS hydrolytic catalyst, and the air speed of the gas material is 1000h^-1The using temperature is 200 ℃, the pressure is 7.0MPa, and the height-diameter ratio of the filling hydrolytic agent layer is 5; the treated blast furnace gas enters a TRT device again to recover energy, the pressure of the gas can be reduced to 5-20kpa, and the temperature is reduced to about 100 ℃; blast furnace gas coming out of the TRT enters a spray tower C, the upper part of the spray tower C is sprayed with NaHS solution and SO in the blast furnace gas₂Carrying out full reaction; the blast furnace gas from the spray tower C enters a spray tower D; the spray liquid from the spray tower C enters a NaHS reflux pool; after entering the spray tower D, the blast furnace gas reacts with a desulfurizer sprayed from the upper part of the spray tower D; after being treatedDischarging blast furnace gas through a gas pipeline; the sprayed desulfurizer enters a desulfurizer regeneration tank; the desulfurizing agent is Fe-containing³⁺KOH solution of chelating agent. Fe-containing alloy used in the present example³⁺The chelating agent of (a) is EDTMPS, and the total iron concentration is 1000 ppm; regulating the content of Fe³⁺The pH of the KOH solution of the chelating agent was 8.

In the embodiment, the hydrogen sulfide removal rate is high, the removal rate of one-step reaction reaches more than 99 percent, and the treated tail gas H₂The concentration of S is below 1 ppm; the running cost is far cheaper than the treatment scheme on the current market, and the method has very great competitiveness.

Example 2

In the same material liquid as in example 1, two desulfurization devices are connected in series, namely A, B, and the device A has the effect of gas purification treatment and mainly purifies elements such as Cl, F, S and the like; hydrolyzing organic sulfur in the device B, and then entering a TRT device to recover energy; the material coming out of the TRT enters a spray tower C, the upper part of the spray tower C sprays NaHS solution and SO in blast furnace gas₂Carrying out full reaction; the blast furnace gas from the spray tower C enters a spray tower D; the spray liquid from the spray tower C enters a NaHS reflux pool; after entering the spray tower D, the blast furnace gas reacts with a desulfurizer sprayed from the upper part of the spray tower D; discharging the blast furnace gas after treatment through a gas pipeline; the sprayed desulfurizer enters a desulfurizer regeneration tank; the desulfurizing agent is Fe-containing³⁺KOH solution of chelating agent. The desulfurizer regeneration tank is also provided with a high-concentration waste liquid discharge port for discharging the high-concentration waste liquid out of the system for treatment. Fe-containing alloy used in the present example³⁺The chelating agent is sodium gluconate, and the total iron concentration is 1000 ppm; regulating the content of Fe³⁺The pH of the KOH solution of the chelating agent was 9. The embodiment has a protection effect on the whole system.

In the embodiment, the hydrogen sulfide removal rate is high, the removal rate of one-step reaction reaches more than 99 percent, and the treated tail gas H₂The S concentration is less than 1 ppm.

Example 3

The same feed liquid as in example 1 was subjected to dry dedusting, and then introduced into a desulfurization unit and a TRT unit for energy recovery, and then introduced into a spray unitSpraying NaHS solution on the upper part of the tower C and SO in blast furnace gas₂Carrying out full reaction; the blast furnace gas from the spray tower C enters a spray tower D; the spray liquid from the spray tower C enters a NaHS reflux pool; after entering the spray tower D, the blast furnace gas reacts with a desulfurizer sprayed from the upper part of the spray tower D; discharging the blast furnace gas after treatment through a gas pipeline; the sprayed desulfurizer enters a desulfurizer regeneration tank; the desulfurizing agent is Fe-containing³⁺KOH solution of chelating agent. The desulfurizer regeneration tank is divided into an absorption zone, an oxidation zone and a degassing zone; the middle desulfurizer is subjected to oxidation reaction, and the absorbed spray liquid firstly enters an absorption area and is rich in hydrogen sulfide; the desulfurizer flowing out of the spray tower D enters an absorption area firstly, then flows into an oxidation area from the absorption area, and is oxidized by air to complete the generation of elemental sulfur and Fe³⁺Regenerating the chelating agent; then the desulfurizing agent flows into a degassing zone from the oxidation zone, and then is conveyed to the upper part of a spray tower D by a conveying pump for absorbing H₂And S. The desulfurizer regeneration tank is also provided with a high-concentration waste liquid discharge port for discharging the high-concentration waste liquid out of the system for treatment. Fe-containing alloy used in the present example³⁺The chelating agent is Na₃HEDTA, total iron concentration 1000 ppm; regulating the content of Fe³⁺The pH of the chelating agent in KOH was 8.5.

In the embodiment, the hydrogen sulfide removal rate is high, the removal rate of one-step reaction reaches more than 99 percent, and the treated tail gas H₂The S concentration is less than 1 ppm.

Example 4

A blast furnace gas pipeline of a low-concentration blast furnace gas containing inorganic sulfur is connected with a dry dust removal device, the dust removal device is then connected with a desulfurization device, the desulfurization device is then connected with a TRT device, the outlet of the TRT device is connected with the inlet of a spray tower C, and the inlet of the spray tower C is positioned at the lower part of the spray tower C; the upper part of the spray tower C is connected with an NaHS solution inlet pipe and a blast furnace gas outlet connecting pipe; the lower part of the spray tower C is also provided with a NaHS solution outlet; the discharging port of the NaHS solution is connected with the NaHS reflux pool; the outlet of the NaHS reflux tank is divided into two paths, wherein one path is used for discharging high-concentration waste liquid, and the other path is connected to a NaHS solution inlet pipe at the upper part of the spray tower C through a pump; a blast furnace gas outlet connecting pipe at the upper part of the spray tower C is connected to an inlet of the spray tower D, and the inlet of the spray tower D is positioned at the lower part of the spray tower D; the lower part of the inlet of the spray tower D is also provided with a desulfurizer discharging port which is connected with a desulfurizer regeneration tank; the upper part of the spray tower D is also provided with a desulfurizer inlet and a blast furnace gas outlet, and the blast furnace gas outlet is connected with a gas pipeline and conveyed outwards; the outlet of the desulfurizer regeneration tank is divided into two paths, one path is used for discharging high-concentration desulfurizer solution, and the other path is connected to a desulfurizer inlet at the upper part of the spray tower D through a pump; the bottom of the desulfurizer regeneration tank is also connected with a sulfur simple substance suction outlet.

The desulfurizing device can be divided into two devices which are connected in series, and the desulfurizing agent regeneration tank can be divided into an absorption zone, an oxidation zone and a degassing zone in sequence. The device is more favorable for the effect of treating the feed liquid.

The apparatus of this example can be applied to examples 1 to 3 of the present application.

Claims (10)

1. A process for treating low-concentration blast furnace gas containing inorganic sulfur is characterized by comprising the following steps:

(1) adsorbing blast furnace gas by activated carbon to remove chlorine and fluorine gases in the blast furnace gas;

(2) adding a hydrolytic agent into the adsorbed blast furnace gas in a desulfurization device to convert organic sulfur in the blast furnace gas into hydrogen sulfide;

(3) the blast furnace gas converted in the step (2) enters a TRT device to recover energy;

(4) blast furnace gas coming out of the TRT enters a spray tower C, the upper part of the spray tower C is sprayed with NaHS solution and SO in the blast furnace gas₂Carrying out full reaction;

the blast furnace gas from the spray tower C enters a spray tower D; the spray liquid from the spray tower C enters a NaHS reflux pool;

(5) after entering the spray tower D, the blast furnace gas reacts with a desulfurizer sprayed from the upper part of the spray tower D; discharging the blast furnace gas after treatment through a gas pipeline; the sprayed desulfurizer enters a desulfurizer regeneration tank(ii) a The desulfurizing agent is Fe-containing³⁺KOH solution of chelating agent.

2. The process for treating low-concentration and low-concentration blast furnace gas containing inorganic sulfur according to claim 1, wherein the blast furnace gas is subjected to dry dedusting before activated carbon adsorption.

3. The method for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: dividing the NaHS solution in the NaHS reflux pool in the step (4) into two paths, and discharging a small amount of high-concentration NaHS solution from the NaHS reflux pool; the other path of NaHS solution reflows to the upper part of the spray tower C to react with the blast furnace gas; the high-concentration NaHS solution refers to a saturated or nearly saturated NaHS solution.

4. The process for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: the desulfurizer regeneration tank in the step (5) is divided into an absorption area, an oxidation area and a degassing area; wherein, the desulfurizer is oxidized, and the absorbed spray liquid firstly enters an absorption area to be rich in hydrogen sulfide; the desulfurizer flowing out of the spray tower D enters an absorption area firstly, then flows into an oxidation area from the absorption area, and is oxidized by air to complete the generation of elemental sulfur and Fe³⁺Regenerating the chelating agent; then the desulfurizing agent flows into a degassing zone from the oxidation zone, and then is conveyed to the upper part of a spray tower D by a conveying pump for absorbing H₂S。

5. The process for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: fe contained in the step (5)³⁺The pH value of the KOH solution of the chelating agent is controlled between 8 and 9.

6. The process for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: and (5) reserving a high-concentration waste liquid discharge port in the desulfurizer regeneration tank, and discharging the high-concentration waste liquid out of the system for treatment.

7. The process for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: fe contained in the step (5)³⁺The chelating agent is HEDP, EDTMPS, DTPMPA, EDDHA, STPP, NTA, Na₃NTA、HEDTA、Na₃HEDTA、Na₄At least one of EDTA, sodium gluconate, sodium metasilicate and potassium tartrate.

8. The process as claimed in claim 1, wherein the hydrolytic agent is MTCOMS-01 type COS hydrolytic catalyst, and the gas material passes through space velocity of 500-^-1The using temperature is 90-260 ℃, the pressure is below 8.0MPa, and the height-diameter ratio of the filling hydrolytic agent layer is 3-6.

9. The apparatus for treating low-concentration blast furnace gas containing inorganic sulfur according to claims 1 to 8, wherein the blast furnace gas pipeline is connected with a dry dust removal device, the dust removal device is then connected with a desulfurization device, the desulfurization device is then connected with a TRT device, the outlet of the TRT device is connected with the inlet of a spray tower C, and the inlet of the spray tower C is positioned at the lower part of the spray tower C; the upper part of the spray tower C is connected with an NaHS solution inlet pipe and a blast furnace gas outlet connecting pipe; the lower part of the spray tower C is also provided with a NaHS solution outlet;

the discharging port of the NaHS solution is connected with the NaHS reflux pool; the outlet of the NaHS reflux tank is divided into two paths, wherein one path is used for discharging high-concentration waste liquid, and the other path is connected to a NaHS solution inlet pipe at the upper part of the spray tower C through a pump;

a blast furnace gas outlet connecting pipe at the upper part of the spray tower C is connected to an inlet of the spray tower D, and the inlet of the spray tower D is positioned at the lower part of the spray tower D; the lower part of the inlet of the spray tower D is also provided with a desulfurizer discharging port which is connected with a desulfurizer regeneration tank; the upper part of the spray tower D is also provided with a desulfurizer inlet and a blast furnace gas outlet, and the blast furnace gas outlet is connected with a gas pipeline and conveyed outwards; the outlet of the desulfurizer regeneration tank is divided into two paths, one path is used for discharging high-concentration desulfurizer solution, and the other path is connected to a desulfurizer inlet at the upper part of the spray tower D through a pump; the bottom of the desulfurizer regeneration tank is also connected with a sulfur simple substance suction outlet.

10. The apparatus for treating low-concentration inorganic sulfur-containing blast furnace gas as claimed in claim 9, wherein the desulfurization apparatus is divided into two apparatuses connected in series, and the desulfurizing agent regeneration tank is divided into at least an absorption zone, an oxidation zone and a degassing zone in this order.

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