CN113684069A - Method and device for treating low-concentration blast furnace gas containing inorganic sulfur - Google Patents

Abstract

The invention discloses the field of chemical production, and particularly relates to a method and a device for treating blast furnace gas containing inorganic sulfur. The blast furnace gas to be treated 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; 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⁺A KOH solution of a chelating agent; the device manufactured by the method comprises a spray tower C, a spray tower D, a desulfurizer regeneration tank and the like. The invention has the advantages of investmentLess, good treatment effect, no secondary pollution and the like.

Description

Method and device for treating low-concentration blast furnace gas containing inorganic sulfur

Technical Field

The invention relates to the field of chemical production, in particular to a method and a device for treating low-concentration 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/Nm³(ii) a 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.

Large amount of blast furnace gas, dispersion of end users and in the gasContaining 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 a plurality of sets of SO2 removing devices for dispersion, the investment is large, the management cost is high, and the whole process 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/Nm³Thereby ensuring that the requirement of 35mg/Nm after the blast furnace gas is combusted in the self-contained power plant is met³SO of (A)₂Discharge 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 column onFine removal of inorganic sulfur: 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, SO after the combustion of the blast furnace gas 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 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) Reaction to produce FeS precipitate and Na₂SO₄The solution, FeS precipitation, 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 method for treating low-concentration blast furnace gas containing inorganic sulfur is characterized by comprising the following steps:

(1) the blast furnace gas to be treated 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;

(2) 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, in the step (1) of the method for treating the low-concentration blast furnace gas containing the inorganic sulfur, the NaHS solution in the NaHS reflux pool 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 (1) is preferably a saturated NaHS solution.

Preferably, the desulfurizing agent regeneration tank in the step (2) of the method for treating the blast furnace gas containing inorganic sulfur with low concentration 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 method for treating low-concentration inorganic sulfur-containing blast furnace gas includes the step (2) of treating the blast furnace gas containing inorganic sulfur³⁺The pH value of the KOH solution of the chelating agent is controlled between 8 and 9.

Preferably, in the step (2) of the method for treating low-concentration inorganic sulfur-containing blast furnace gas, a high-concentration waste liquid discharge port is provided in the desulfurizing agent regeneration tank, and the high-concentration waste liquid is discharged from the system for treatment.

Preferably, the method for treating low-concentration inorganic sulfur-containing blast furnace gas includes the step (2) of treating the low-concentration inorganic sulfur-containing blast furnace gas³⁺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.

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⁺) Cannot exist stably, and generally, iron hydroxide or iron sulfide precipitate is easily formed through the following 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:

column C 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 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.

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 the components are respectively 15-22% and 55%, and a small amount of SO₂、H₂S, COS and hydroxysulfur, etc., and has a calorific value of about 3500KJ/m³) Enters a spray tower C, the upper part of the spray tower C is sprayed with NaHS solution and SO in the blast furnace gas₂And the like to carry out a sufficient 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; the NaHS solution in the NaHS reflux pool is divided into two paths, and a small amount of high-concentration nearly saturated 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 and is mixed with the newly supplemented NaHS solution.

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. 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 lower than that of the current market, and the method has huge competitiveness.

Example 2

The same feed liquid as in example 1 was fed into a spray tower C, and the upper part of the spray tower C was sprayed with NaHS solution, together with 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.

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 fed into a spray tower C, and the upper part of the spray tower C was sprayed with NaHS solution, together with 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 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.

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 processing device containing inorganic sulfur is provided, wherein 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. The desulfurizer regeneration tank is at least sequentially divided into an absorption zone, an oxidation zone and a degassing zone.

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

Claims (9)

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

(1) the blast furnace gas to be treated 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;

(2) 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.

2. 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 (1) into two paths, and discharging a small amount of high-concentration NaHS solution 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.

3. The method for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 2, characterized in that: the high-concentration NaHS solution in the step (1) is a NaHS saturated solution.

4. The method for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: the desulfurizer regeneration tank in the step (2) is divided into an absorption area, an oxidation area and a degassing area; 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。

5. The method for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: fe contained in the step (2)³⁺The pH value of the KOH solution of the chelating agent is controlled between 8 and 9.

6. The method for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: and (3) a high-concentration waste liquid discharge port is reserved in the desulfurizer regeneration tank in the step (2), and the high-concentration waste liquid is discharged out of the system for treatment.

7. The method for treating low-concentration inorganic sulfur-containing blast furnace gas according to claim 1, characterized in that: fe contained in the step (2)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 apparatus for treating low-concentration inorganic sulfur-containing blast furnace gas according to claims 1 to 7, wherein the blast furnace gas pipeline is connected to an inlet of a spray tower C, and the inlet of the spray tower C is located at a lower portion 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.

9. The apparatus for treating low-concentration inorganic sulfur-containing blast furnace gas as claimed in claim 8, wherein the desulfurizing agent regenerating tank is divided into at least an absorption zone, an oxidation zone and a degassing zone in this order.

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