CN114250088A

CN114250088A - Composite solvent for removing carbonyl sulfide in blast furnace gas and application thereof

Info

Publication number: CN114250088A
Application number: CN202111106681.6A
Authority: CN
Inventors: 贾勇
Original assignee: Yuanheng Shanghai Environmental Technology Co ltd
Current assignee: Yuanheng Shanghai Environmental Technology Co ltd
Priority date: 2020-09-25
Filing date: 2021-09-22
Publication date: 2022-03-29

Abstract

The invention provides a composite solvent for removing carbonyl sulfide in blast furnace gas and application thereof, wherein the composite solvent comprises 89-98.9 wt% of an organic alcohol amine compound, 0.1-1 wt% of a stabilizer, 0.5-5 wt% of an activator and 0.5-5 wt% of an accelerator, and the organic alcohol amine compound comprises a primary alcohol amine compound and a tertiary alcohol amine compound. The composite solvent provided by the invention can be applied to a blast furnace gas pre-desulfurization process, carbonyl sulfide in the blast furnace gas can be efficiently removed, the removal rate can reach 90%, and the composite solvent can be recycled, has no secondary pollutant emission, greatly reduces the operation cost and has high economic benefit.

Description

Composite solvent for removing carbonyl sulfide in blast furnace gas and application thereof

Technical Field

The invention belongs to the technical field of blast furnace gas desulfurization, and particularly relates to a compound solvent for removing carbonyl sulfide in blast furnace gas and application thereof.

Background

The blast furnace gas is a byproduct low-calorific-value combustible gas containing carbon monoxide, carbon dioxide, nitrogen and hydrogen in the iron making process of iron and steel enterprises, has large yield and wide application, and can be used as a fuel of blast furnace hot blast furnaces, steel rolling heating furnaces and self-contained electric boilers of steel plants. The blast furnace gas without purification also contains largeDust and sulfides are mainly divided into organic sulfur and inorganic sulfur, and the proportion of organic sulfur is higher than that of inorganic sulfur and is about 70-85%. The main components of the organic sulfur comprise carbonyl sulfide (COS) and carbon disulfide (CS)₂) Sulfur ether, mercaptan, etc. with COS accounting for 60-85% of the total sulfur content; the inorganic sulfur mainly contains hydrogen sulfide and also contains a small amount of sulfur dioxide. The emission of sulfur dioxide in flue gas of blast furnace gas after untreated combustion exceeds standard, and SO in the flue gas emitted by the blast furnace gas is generally excessive₂The content is more than 50mg/Nm³Sometimes even up to 200mg/Nm³The above.

At present, blast furnace gas desulfurization is basically carried out by steel enterprises by terminal treatment, namely, the blast furnace gas is sent to subsequent devices such as a hot blast stove and a heating furnace after being subjected to dust removal and purification and TRT power generation, and organic sulfur is converted into inorganic Sulfur (SO) after being combusted₂) Then carrying out desulfurization treatment, also called post-desulfurization process. However, the sulfur content after the end treatment can not meet the latest national ultra-clean emission requirement (lower than 50 mg/Nm)³Partial areas require less than 35mg/Nm³The latest environmental policy requires that the steel industry needs to reach less than 35mg/Nm by the end of 2025³). At present, the main technologies of tail end treatment include SDS, circulating fluidized bed semidry method, active carbon method and the like, which need to arrange desulfurization facilities (hot blast stove, heating furnace, gas-fired boiler and the like) at multiple points, not only the occupied area is large, the equipment maintenance points are more, but also because of tail end desulfurization, the blast furnace gas contains H₂S seriously corrodes TRT facilities and conveying pipelines, the service life of the generator is shortened, and the early-stage investment cost and the later-stage maintenance cost are high.

Therefore, before the blast furnace gas is combusted, the sulfide in the blast furnace gas is directly removed, and the blast furnace gas is combusted after the sulfur is removed, so that the content of sulfur dioxide in the combusted flue gas can meet the national ultra-low emission requirement, and a post-desulfurization process is not required. The pre-desulfurization process is simple, the occupied area is small, the operation cost is low, no by-product which is difficult to treat is generated, the purified coal gas is directly supplied to various downstream production units to be used as energy for combustion, the national ultra-low emission requirement can be directly met, the solid waste is not generated, the service life of the coal gas pipeline can be prolonged due to the reduction of corrosion, the economic benefit and the social benefit are greatly improved, and the desulfurization cost is greatly reduced.

The sulfur in the blast furnace gas is mainly COS, and the desulfurization of the blast furnace gas is mainly to remove the COS. Because the carbonyl sulfide has stable property, the carbonyl sulfide is difficult to directly carry out chemical reaction with other compounds in the oxygen-free environment of blast furnace gas, is not easy to dissociate and liquefy, and is difficult to remove.

There are many techniques currently employed for gas desulfurization, the most common being to contact an acid gas stream with an organic solvent (or aqueous solution of an organic solvent) in a gas purification unit. In general, there are roughly two different gas purification solvents.

The first is a physical solvent, followed by physical absorption. Typical physical solvents are sulfolane and its derivatives, linear amides, pyrrolidones, methanol, and mixtures of polyvinyl alcohol dialkyl ethers.

The second is a chemical solvent, which is a compound that generates an acid gas by a chemical reaction to be easily removed. For example, the most common chemical solvent used in industry is an alcohol amine, because the resulting salts are easily decomposed or stripped by steam, and the amine can therefore be recycled. Among the preferred amines for removing acidic components from gas streams are Monoethanolamine (MEA), Diethanolamine (DEA), Triethanolamine (TEA), Diisopropanolamine (DIPA), Aminoethoxyethanol (AEE), Methyldiethanolamine (MDEA), and MDEA with various activators added.

In general, the above-mentioned solvent pairs remove H₂S and CO₂Has higher efficiency, but has a plurality of difficulties for organic sulfur, especially carbonyl sulfur. Physical solvents can remove organic sulfur to very low levels, but their regeneration is expensive and not suitable for large-scale industrial use. In the chemical solvent, the hydrolysis rate of various alcohol amines to COS is not high, the hydrolysis process is very slow, the removal rate is very low, thiol compounds are removed by physical dissolution, and the removal effect to organic sulfur is very poor because the hydrolysis degree of thiol in an alcohol amine aqueous solution is very low. After the amine treatment, catalytic hydrolysis or alkaline washing, catalytic oxygen are often usedThe chemical sweetening, and the fixed bed dry fine desulphurization lead to the problems of multiple desulphurization overall steps and long total flow, thus having more equipment, large investment and high total consumption index.

Therefore, in order to remove carbonyl sulfide in blast furnace gas at the front end, the invention provides a compound solvent, which can efficiently and deeply remove carbonyl sulfide in blast furnace gas without adding extra equipment, and can be recycled, so that the economic benefit is high.

Disclosure of Invention

In view of the above problems in the prior art, an object of the present invention is to provide a composite solvent for removing carbonyl sulfide from blast furnace gas, which can effectively promote a reaction of removing organic sulfur from an alcohol amine compound, especially promote the removal of carbonyl sulfide from the alcohol amine compound, and has a removal rate of carbonyl sulfide as high as 90% or more.

The invention provides a compound solvent for removing carbonyl sulfide in blast furnace gas, which comprises 89-98.9 wt% of an organic alcohol amine compound, 0.1-1 wt% of a stabilizer, 0.5-5 wt% of an activator and 0.5-5 wt% of an accelerator, wherein the organic alcohol amine compound comprises a primary alcohol amine compound and a tertiary alcohol amine compound.

Further, the primary alcohol amine compound has 3 to 8 carbon atoms, and the tertiary alcohol amine compound has 3 to 6 carbon atoms.

Further, the primary alcohol amine compound is 2-amino-2-methyl-1-propanol (AMP) and/or 2-amino-1, 3-butanediol, and the primary alcohol amine compound accounts for 10-30 wt% of the organic alcohol amine compound.

Further, the tertiary alcohol amine compound is methyl diethanol amine (MDEA), and the proportion of the tertiary alcohol amine compound in the organic alcohol amine compound is 70-90 wt%.

Preferably, the primary alcohol amine compound is present in an amount of 15 to 25 wt% in the organic alcohol amine compound, and the tertiary alcohol amine compound is present in an amount of 75 to 85 wt% in the organic alcohol amine compound.

Further preferably, the primary alcohol amine compound accounts for 20 wt% of the organic alcohol amine compound, and the tertiary alcohol amine compound accounts for 80 wt% of the organic alcohol amine compound.

Preferably, the stabilizer is a polyether polyol and/or a polyethylene glycol alkyl ether.

Preferably, the polyether polyol is polyoxyethylene propylene glycol ether, propylene oxide propylene glycol ether or polyoxypropylene propylene glycol ether, and the molecular weight of the polyether polyol is 800-4000.

Preferably, the carbon atom number of the alkyl in the polyethylene glycol alkyl ether is 10-16, and the molecular weight of the polyethylene glycol alkyl ether is 400-4000.

More preferably, the number of carbon atoms in the alkyl group in the polyethylene glycol alkyl ether is 12.

Preferably, the activator is formylmorpholine and derivatives thereof.

Further preferably, the activator is N-formylmorpholine.

Preferably, the accelerator is hydroxyethyl piperazine.

Preferably, the pH of the composite solvent is 11 to 12.

The invention also provides the application of the compound solvent in removing carbonyl sulfide of blast furnace gas, and water is added into the compound solvent to dilute the compound solvent to 30-50 wt% for use.

Preferably, the composite solvent is used by adding water to dilute the solvent to 40 wt%.

Furthermore, the compound solvent is used after the blast furnace gas is deprived of hydrogen chloride, and the content of the hydrogen chloride in the blast furnace gas is lower than 5mg/m³。

Further, the composite solvent is used in the blast furnace gas front desulphurization process.

Further, the volume gas-liquid ratio of the blast furnace gas to the composite solvent is 400-600.

Further preferably, the volume gas-liquid ratio of the blast furnace gas to the composite solvent is 500.

Furthermore, the temperature of the blast furnace gas is not higher than 40 ℃, and the pressure is 10-20 kPa.

The principle of removing carbonyl sulfide in blast furnace gas by using the composite solvent provided by the invention is as follows: the compound solvent diluted by water is in gas-liquid reverse contact with blast furnace gas in the desulfurizing tower, and the existence of the accelerator can accelerate the mass transfer process from gas phase to liquid phase, so that carbonyl sulfide in the gas is accelerated to diffuse into the liquid phase; the alcohol amine compound in the compound solvent can physically dissolve part of carbonyl sulfide, and then the carbonyl sulfide and the alcohol amine compound are subjected to rapid hydrolysis reaction under the action of an activating agent to generate hydrogen sulfide and carbon dioxide, and the hydrogen sulfide and the carbon dioxide are further reacted with the alcohol amine compound in a desulfurization tower to generate amine salt, so that the carbonyl sulfide in the blast furnace gas is efficiently removed.

The mechanism of the reaction between carbonyl sulfide and alcohol amine compound is as follows:

namely, the total reaction is as follows: COS + H₂O＝H₂S+CO₂

Wherein R is₁，R₂，R₃At least one of which contains a hydroxyl group.

The mechanism of the reaction of hydrogen sulfide and an alcohol amine compound to form an amine salt is as follows:

the mechanism of the reaction of carbon dioxide and an alcohol amine compound to form an amine salt is as follows:

the reaction of hydrogen sulfide and carbon dioxide with the alcohol amine compound to generate amine salt is reversible, and the reaction is carried out rightward at low temperature, and the reaction is carried out leftward after heating.

The solution absorbing sulfide in the desulfurizing tower is called as rich solution, the rich solution enters a regeneration tower and then is heated and regenerated to obtain barren solution and acid gas, and the regenerated barren solution enters the desulfurizing tower for recycling, so that the compound solvent can be effectively recycled, and the operation cost is reduced.

The invention has the beneficial effects that:

1. the composite solvent provided by the invention can effectively remove organic sulfur (carbonyl sulfur) in blast furnace gas, the removal rate can reach 90% or more, meanwhile, the composite solvent has good selective absorptivity for inorganic sulfur (hydrogen sulfide), and the composite solvent can be recycled, has no secondary pollutant emission, greatly reduces the operation cost and has high economic benefit;

2. the composite solvent has high efficiency of removing carbonyl sulfide, the hydrolysis reaction after the carbonyl sulfide is contacted with the composite solvent is extremely fast, more than 90 percent of carbonyl sulfide in blast furnace gas can be effectively removed after the gas-liquid contact is carried out for 15-30 seconds, and clean gas with the total sulfur content lower than the national ultra-low emission standard is generated and is directly discharged from an equipment outlet to be supplied to each downstream production unit;

3. the compound solvent can be used at normal temperature (not higher than 40 ℃) and ultralow pressure (10-20kPa), has low requirement on equipment, can be widely applied to the blast furnace gas front desulfurization process, and reduces the emission content of sulfur from the source.

Detailed Description

The following are specific examples of the present invention and further describe the technical solutions of the present invention, but the scope of the present invention is not limited to these examples. All changes, modifications and equivalents that do not depart from the spirit of the invention are intended to be included within the scope thereof.

The desulfurization performance was tested on a test apparatus using a specific complex solvent. Before the blast furnace gas enters the desulfurizing tower, HCl removal treatment is carried out on the blast furnace gas to ensure that the content of HCl in the blast furnace gas is lower than 5mg/m³. In the test, COS and H are firstly measured at the blast furnace gas inlet (namely, raw material gas) of the desulfurizing tower₂The content of S is measured at a blast furnace gas outlet (namely, purified gas) of the desulfurizing tower after the gas-liquid contact is carried out for 15 to 30 seconds₂The content of S. The average value was taken in triplicate for each test condition. The specific test conditions were as follows:

example 1:

mother liquor: 9.9 wt% of 2-amino-2-methyl-1-propanol, 89 wt% of methyldiethanolamine, 0.1 wt% of polyethylene glycol dodecyl ether (molecular weight 400), 0.5 wt% of N-formyl morpholine and 0.5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 30 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 400(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 2:

mother liquor: 9.9 wt% of 2-amino-2-methyl-1-propanol, 89 wt% of methyldiethanolamine, 0.1 wt% of polyethylene glycol dodecyl ether (molecular weight 400), 0.5 wt% of N-formyl morpholine and 0.5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 30 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 3:

mother liquor: 9.9 wt% of 2-amino-2-methyl-1-propanol, 89 wt% of methyldiethanolamine, 0.1 wt% of polyethylene glycol dodecyl ether (molecular weight 400), 0.5 wt% of N-formyl morpholine and 0.5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 30 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 600(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 4:

mother liquor: 9.9 wt% of 2-amino-2-methyl-1-propanol, 89 wt% of methyldiethanolamine, 0.1 wt% of polyethylene glycol dodecyl ether (molecular weight 800), 0.5 wt% of N-formyl morpholine and 0.5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 40 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 5:

mother liquor: 9.9 wt% of 2-amino-2-methyl-1-propanol, 89 wt% of methyldiethanolamine, 0.1 wt% of polyethylene glycol dodecyl ether (molecular weight 800), 0.5 wt% of N-formyl morpholine and 0.5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 50 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 6:

mother liquor: 9.9 wt% of 2-amino-2-methyl-1-propanol, 89 wt% of methyldiethanolamine, 0.1 wt% of polyethylene glycol dodecyl ether (molecular weight 4000), 0.5 wt% of N-formyl morpholine and 0.5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 40 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 7:

mother liquor: 19.5 wt% of 2-amino-2-methyl-1-propanol, 78 wt% of methyldiethanolamine, 0.5 wt% of polyoxyethylene glycerol ether (molecular weight 800), 1 wt% of N-formyl morpholine and 1 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 40 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 8:

mother liquor: 23.2 wt% of 2-amino-2-methyl-1-propanol, 69.8 wt% of methyldiethanolamine, 1 wt% of polyoxyethylene glycerol ether (molecular weight 800), 3 wt% of N-formyl morpholine and 3 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 40 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 9:

mother liquor: 26.7 wt% of 2-amino-2-methyl-1-propanol, 62.3 wt% of methyldiethanolamine, 1 wt% of polyoxyethylene glycerol ether (molecular weight 800), 5 wt% of N-formyl morpholine and 5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 40 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 40 deg.C, and the gas pressure at 10 kPa. The data obtained by the test are shown in Table 1.

Example 10:

mother liquor: 9.9 wt% of 2-amino-1, 3-butanediol, 89 wt% of methyldiethanolamine, 0.1 wt% of polyoxypropylene glycerol ether (molecular weight 2000), 0.5 wt% of formylmorpholine and 0.5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 40 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 30 deg.C, and the gas pressure at 20 kPa. The data obtained by the test are shown in Table 1.

Example 11:

mother liquor: 26.7 wt% of 2-amino-1, 3-butanediol, 62.3 wt% of methyldiethanolamine, 1 wt% of polyoxypropylene glycerol ether (molecular weight 2000), 5 wt% of formylmorpholine and 5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 40 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 30 deg.C, and the gas pressure at 20 kPa. The data obtained by the test are shown in Table 1.

Example 12:

mother liquor: 9.9 wt% of 2-amino-1, 3-butanediol, 89 wt% of methyldiethanolamine, 0.1 wt% of polyoxypropylene glycerol ether (molecular weight 4000), 0.5 wt% of formylmorpholine and 0.5 wt% of hydroxyethyl piperazine. Adding water to dilute the mother liquor to 40 wt%, adding into a desulfurizing tower, controlling the gas-liquid ratio at 500(v/v), the temperature at 30 deg.C, and the gas pressure at 20 kPa. The data obtained by the test are shown in Table 1.

Table 1: COS and H in raw material gas and purified gas₂S content and removal rate thereof

As can be seen from the data in Table 1, the removal rate of carbonyl sulfide in blast furnace gas by the composite solvent provided by the application is very high, and can reach more than 90% in most cases, and the removal rate of hydrogen sulfide can also reach more than 70%, and the total sulfur content of the purified gas is lower than the national ultra-low emission standard (35 mg/Nm)³) The waste water can be directly discharged from the outlet of the equipment and supplied to each downstream production unit without secondary treatment.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims

1. The compound solvent for removing carbonyl sulfide in blast furnace gas is characterized by comprising 89-98.9 wt% of an organic alcohol amine compound, 0.1-1 wt% of a stabilizer, 0.5-5 wt% of an activator and 0.5-5 wt% of an accelerator, wherein the organic alcohol amine compound comprises a primary alcohol amine compound and a tertiary alcohol amine compound.

2. The complex solvent according to claim 1, wherein the primary alcohol amine compound has 3 to 8 carbon atoms, and the tertiary alcohol amine compound has 3 to 6 carbon atoms.

3. The complex solvent according to claim 1 or 2, wherein the primary alcohol amine compound is 2-amino-2-methyl-1-propanol and/or 2-amino-1, 3-butanediol, and the primary alcohol amine compound is present in an amount of 10 to 30 wt% based on the organic alcohol amine compound.

4. The composite solvent according to claim 1 or 2, wherein the tertiary alkanolamine compound is methyldiethanolamine, and the tertiary alkanolamine compound accounts for 70 to 90 wt% of the organic alkanolamine compound.

5. The complex solvent according to claim 1, wherein the primary alcohol amine compound accounts for 20 wt% of the organic alcohol amine compound, and the tertiary alcohol amine compound accounts for 80 wt% of the organic alcohol amine compound.

6. The composite solvent according to claim 1, wherein the stabilizer is polyether polyol and/or polyethylene glycol alkyl ether.

7. The composite solvent according to claim 6, wherein the polyether polyol is polyoxyethylene propylene glycol ether, propylene oxide propylene glycol ether or polyoxypropylene propylene glycol ether, and the molecular weight of the polyether polyol is 800-4000.

8. The composite solvent according to claim 6, wherein the number of carbon atoms in the alkyl group in the polyethylene glycol alkyl ether is 10 to 16, and the molecular weight of the polyethylene glycol alkyl ether is 400 to 4000.

9. A composite solvent as set forth in claim 8, wherein the alkyl group has 12 carbon atoms.

10. The composite solvent according to claim 1, wherein the activator is formylmorpholine and its derivatives.

11. The composite solvent of claim 10, wherein the activator is N-formyl morpholine.

12. The composite solvent according to claim 1, wherein the accelerator is hydroxyethyl piperazine.

13. The hybrid solvent according to claim 1, wherein the pH of the hybrid solvent is 11 to 12.

14. The application of the compound solvent in removing carbonyl sulfide in blast furnace gas according to any one of claims 1 to 13, wherein the compound solvent is used by adding water to dilute the compound solvent to 30 to 50 wt%.

15. The use according to claim 14, wherein the multi-component solvent is used by diluting the concentration to 40 wt% with water.

16. The use according to claim 14 or 15, characterized in that the composite solvent is used after removal of hydrogen chloride from blast furnace gas, the hydrogen chloride content of which is less than 5mg/m³。

17. The use according to claim 16, wherein the hybrid solvent is used in a blast furnace gas pre-desulfurization process.

18. The use according to claim 16, wherein the volumetric gas-liquid ratio of the blast furnace gas to the composite solvent is 400-600.

19. The use according to claim 16, wherein the volumetric gas-liquid ratio of the blast furnace gas to the composite solvent is 500.

20. The use according to claim 16, wherein the blast furnace gas has a temperature of not more than 40 ℃ and a pressure of 10-20 kPa.