Composite organic solvent for removing organic sulfur in coke oven gas and application thereof
By using composite organic solvents to selectively absorb and hydrolyze organic sulfur in coke oven gas at room temperature and low pressure, the problem of difficult removal of organic sulfur before combustion of coke oven gas is solved, achieving efficient and economical pre-desulfurization effect and meeting national emission standards.
Patent Information
- Application Number
- CN202511220371.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-28
- Publication Date
- 2025-10-28
AI Technical Summary
Existing technologies are insufficient to effectively remove organic sulfur before coke oven gas combustion, resulting in excessive sulfur dioxide levels in the flue gas after combustion. Furthermore, end-of-pipe treatment methods are costly, require large land areas, and involve complex equipment maintenance, making it difficult to meet national ultra-low emission requirements.
A composite organic solvent, comprising an organic sulfur selective absorber and an active substance, is used to selectively absorb and hydrolyze organic sulfur by contacting coke oven gas at room temperature and low pressure, generating easily treatable sulfides, thus realizing a pre-desulfurization process.
It achieves a high efficiency removal rate (over 80%) of organic sulfur in coke oven gas, reduces operating costs, avoids secondary pollution, meets national ultra-low emission standards, and simplifies equipment requirements.
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Figure CN120843160A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of desulfurization technology, and in particular to a composite organic solvent for removing organic sulfur from coke oven gas and its application. Background Technology
[0002] Coke oven gas contains a large amount of sulfides, mainly divided into organic sulfur and inorganic sulfur, with organic sulfur accounting for up to 90%. The main components of organic sulfur include carbonyl sulfide (COS), carbon disulfide (CS2), sulfides, and thiols, with carbon disulfide accounting for the highest proportion, reaching 50%-60%, followed by carbonyl sulfide, accounting for 30%-40%.
[0003] Carbon disulfide (CS2) and carbonyl sulfide (COS) in coke oven gas are organic sulfur compounds, structurally similar to CO2. They are stable and rarely react directly with other compounds during coke oven gas generation and use. Their molecular structure is relatively simple, linear, with oxygen and carbon atoms linked by double bonds. The compact molecular structure, with the S and C atoms tightly bound together in their spatial orbitals, makes them difficult to dissociate or liquefy, thus hindering their removal. Direct combustion of untreated coke oven gas results in sulfur dioxide levels significantly exceeding safety standards.
[0004] Currently, in China's coking industry, coke oven gas is used as a power source, and almost all of it relies on end-of-pipe treatment. This involves converting organic sulfur into inorganic sulfur (SO2) after combustion, followed by desulfurization. The main technologies include SDS, circulating fluidized bed semi-dry method, and activated carbon method. End-of-pipe treatment is characterized by multiple desulfurization facilities (e.g., in steel rolling furnaces and gas-fired boilers), high treatment costs, large land area requirements, difficult retrofitting, numerous equipment maintenance points, large personnel requirements, high requirements for operating temperature stability, and severe corrosion of gas transmission pipelines. Furthermore, with increasingly stringent national environmental policies, the results of end-of-pipe treatment may not meet ultra-low emission requirements (below 50 mg / Nm³) in the next few years. 3 In some regions, the requirement is below 35 mg / Nm 3 The latest environmental protection policy requires that by the end of 2025, the entire steel industry must achieve a concentration of less than 35 mg / Nm³. 3 ).
[0005] Therefore, it is necessary to remove sulfides from the coke oven gas directly before combustion. After desulfurization, combustion can achieve the national ultra-low emission requirements for sulfur dioxide in the flue gas, eliminating the need for post-desulfurization processes. This method is called pre-desulfurization, also known as source control. Pre-desulfurization is simple, requires less land, has lower operating costs, and produces no difficult-to-treat byproducts. The purified gas can be directly supplied to downstream production units as energy, meeting national ultra-low emission requirements directly. No solid waste is generated, and gas pipelines experience reduced corrosion, extending their service life. This significantly improves economic and social benefits while greatly reducing desulfurization costs.
[0006] Therefore, those skilled in the art are dedicated to developing a desulfurizing agent that can remove organic sulfur from coke oven gas in the pre-desulfurization process and meet national emission requirements. Summary of the Invention
[0007] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is how to develop a desulfurizing agent that can remove organic sulfur from coke oven gas in the pre-desulfurization process and meet national emission requirements.
[0008] To achieve the above objectives, the present invention provides a composite organic solvent for removing organic sulfur from coke oven gas, comprising an organic sulfur selective absorbent, an active substance, and water; The organic sulfur selective absorbent is configured to selectively absorb the organic sulfur; The active substance is configured to accelerate the absorption rate of the organic sulfur by the selective organic sulfur absorbent. The organic sulfur selective absorbent has a weight percentage of 76 wt% and 89 wt%, and the active substance has a weight percentage of 1.5 wt% and 2 wt%.
[0009] Furthermore, the organic sulfur selective absorbent includes sulfolane.
[0010] Furthermore, the weight percentage of sulfolane is greater than or equal to 38 wt% and less than or equal to 42 wt%.
[0011] Furthermore, the organic sulfur selective absorbent includes methyldiethanolamine.
[0012] Furthermore, the weight percentage of the methyldiethanolamine is greater than or equal to 38 wt% and less than or equal to 42 wt%.
[0013] Furthermore, the organic sulfur selective absorbent includes methyl monoethanolamine.
[0014] Furthermore, the weight percentage of the methyl monoethanolamine is less than or equal to 5 wt%.
[0015] Furthermore, the active substance includes diisopropanolamine.
[0016] Furthermore, the weight percentage of the diisopropanolamine is greater than or equal to 1 wt% and less than or equal to 1.5 wt%.
[0017] Furthermore, the active substance includes tetraethylene glycol dimethyl ether.
[0018] Furthermore, the weight percentage of the tetraethylene glycol dimethyl ether is less than or equal to 0.5 wt%.
[0019] Furthermore, an application of a composite desulfurization organic solvent in removing organic sulfur from coke oven gas is provided, wherein the composite desulfurization organic solvent is the aforementioned composite organic solvent for removing organic sulfur, and the organic sulfur contains CS2.
[0020] Furthermore, the CS2 accounts for more than or equal to 50% of the organic sulfur.
[0021] Furthermore, the organic sulfur also includes COS and thiols.
[0022] Furthermore, the COS accounts for more than or equal to 30% of the organic sulfur.
[0023] Furthermore, the organic sulfur is organic sulfur found in coke oven gas.
[0024] Furthermore, the temperature of the coke oven gas is not higher than 50°C.
[0025] Furthermore, the pressure of the coke oven gas is ultra-low pressure.
[0026] Furthermore, the ultra-low pressure is less than or equal to 8 kPa.
[0027] Furthermore, the composite desulfurization organic solvent is used in the pre-desulfurization process of coke oven gas. The pre-desulfurization process of coke oven gas refers to directly removing sulfides from the coke oven gas before combustion. After desulfurization, combustion is carried out, so that the sulfur dioxide content in the flue gas after combustion can meet the national ultra-low emission requirements. This method is also known as source control.
[0028] The beneficial effects of this invention are as follows: 1. The composite solvent provided by this invention can effectively remove organic sulfur from coke oven gas, especially carbon disulfide, which has a higher content. The total organic sulfur removal rate can reach 80% or more. At the same time, it also has good selective absorption of inorganic sulfur (hydrogen sulfide). Furthermore, the composite solvent can be recycled and there is no secondary pollutant emission, which greatly reduces operating costs and has high economic benefits. 2. This composite solvent has a high efficiency in removing organic sulfur. With the synergy of active substances, the organic sulfur selective absorbent can quickly and specifically absorb organic sulfur and accelerate its hydrolysis reaction. After gas-liquid contact for about 30-60 seconds, more than 80% of the organic sulfur in coke oven gas can be effectively removed, generating clean gas with a total sulfur content lower than the national ultra-low emission standard, which is directly supplied to downstream production units from the equipment outlet. 3. This composite solvent has a high absorption rate of organic sulfur but a low absorption rate of other organic compounds (benzene compounds, phenols, naphthalene, various hydrocarbons, etc.), which can avoid the adverse effects of other organic compounds on the solvent. 4. This composite solvent can be used at room temperature (not higher than 50℃) and ultra-low pressure (5-8kPa), with low equipment requirements. It can be widely used in the desulfurization process before coke oven gas to reduce sulfur emissions from the source.
[0029] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description
[0030] Figure 1 This is the total sulfur removal rate result of a preferred embodiment of the present invention. Detailed Implementation
[0031] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention. However, the scope of protection of the present invention is not limited to these embodiments. All changes or equivalent substitutions that do not depart from the concept of the present invention are included within the scope of protection of the present invention.
[0032] Example 1
[0033] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine and methyl monoethanolamine, and the active substances include diisopropanolamine (DIPA amine) and dimethylaminoethoxyethanol. The specific proportions of each substance are as follows: 80 wt% methyl diethanolamine, 5 wt% methyl monoethanolamine, 1.5 wt% diisopropanolamine, 0.5 wt% dimethylaminoethoxyethanol, and the remainder is water as a solvent; The reaction conditions were: temperature 50℃ and pressure 8kPa.
[0034] The measured data are shown in Table 1.
[0035] Example 2
[0036] The formulation of the composite organic solvent is as follows: Organic sulfur selective absorbers include methyl diethanolamine, sulfolane, and methyl monoethanolamine. The specific proportions of each substance are as follows: 40 wt% methyl diethanolamine, 40 wt% sulfolane, 5 wt% methyl monoethanolamine, and the remainder is water as solvent; the reaction conditions are: temperature 50℃ and pressure 8 kPa.
[0037] The measured data are shown in Table 1.
[0038] Example 3
[0039] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine and sulfolane, and the active substance includes diisopropanolamine. The specific proportions of each substance are as follows: methyl diethanolamine 42wt%, sulfolane 43wt%, diisopropanolamine 1.5wt%, and the remainder is water as a solvent; The reaction conditions were: temperature 50℃ and pressure 8kPa.
[0040] The measured data are shown in Table 1.
[0041] Example 4
[0042] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine, sulfolane, and methyl monoethanolamine, and the active substance includes diisopropanolamine; The specific proportions of each substance are as follows: 40 wt% methyl diethanolamine, 40 wt% sulfolane, 3 wt% methyl monoethanolamine, 1.2 wt% diisopropanolamine, and the remainder is water as a solvent; The reaction conditions were: temperature 50℃ and pressure 8kPa.
[0043] The measured data are shown in Table 1.
[0044] Example 5
[0045] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine, sulfolane, and methyl monoethanolamine, and the active substances include diisopropanolamine and dimethylaminoethoxyethanol. The specific proportions of each substance are as follows: methyl diethanolamine 38wt%, sulfolane 42wt%, methyl monoethanolamine 3wt%, diisopropanolamine 1.2wt%, dimethylaminoethoxyethanol 0.3wt%, and the remainder is water as a solvent; The reaction conditions were: temperature 50℃ and pressure 8kPa.
[0046] The measured data are shown in Table 1.
[0047] Example 6
[0048] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine, sulfolane, and methyl monoethanolamine, and the active substances include diisopropanolamine and dimethylaminoethoxyethanol. The specific proportions of each substance are as follows: 42 wt% methyl diethanolamine, 38 wt% sulfolane, 5 wt% methyl monoethanolamine, 1 wt% diisopropanolamine, 0.2 wt% dimethylaminoethoxyethanol, and the remainder is water as a solvent; The reaction conditions were: temperature 50℃ and pressure 8kPa.
[0049] The measured data are shown in Table 1.
[0050] Example 7
[0051] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine, sulfolane, and methyl monoethanolamine, and the active substances include diisopropanolamine and dimethylaminoethoxyethanol. The specific proportions of each substance are as follows: 42 wt% methyl diethanolamine, 42 wt% sulfolane, 5 wt% methyl monoethanolamine, 1.5 wt% diisopropanolamine, 0.5 wt% dimethylaminoethoxyethanol, and the remainder is water as a solvent; The reaction conditions were: temperature 50℃ and pressure 8kPa.
[0052] The measured data are shown in Table 1.
[0053] Example 8
[0054] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine, sulfolane, and methyl monoethanolamine, and the active substances include diisopropanolamine and dimethylaminoethoxyethanol. The specific proportions of each substance are as follows: methyl diethanolamine 38wt%, sulfolane 38wt%, methyl monoethanolamine 5wt%, diisopropanolamine 1wt%, dimethylaminoethoxyethanol 0.5wt%, and the remainder is water as a solvent; The reaction conditions were: temperature 50℃ and pressure 8kPa.
[0055] The measured data are shown in Table 1.
[0056] Example 9
[0057] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine, sulfolane, and methyl monoethanolamine, and the active substances include diisopropanolamine and dimethylaminoethoxyethanol. The specific proportions of each substance are as follows: 42 wt% methyl diethanolamine, 42 wt% sulfolane, 5 wt% methyl monoethanolamine, 1.5 wt% diisopropanolamine, 0.5 wt% dimethylaminoethoxyethanol, and the remainder is water as a solvent; The reaction conditions were: temperature 50℃ and pressure 5kPa.
[0058] The measured data are shown in Table 1.
[0059] Example 10
[0060] The formulation of the composite organic solvent is as follows: The organic sulfur selective absorbents include methyl diethanolamine, sulfolane, and methyl monoethanolamine, and the active substances include diisopropanolamine and dimethylaminoethoxyethanol. The specific proportions of each substance are as follows: 42 wt% methyl diethanolamine, 42 wt% sulfolane, 5 wt% methyl monoethanolamine, 1.5 wt% diisopropanolamine, 0.5 wt% dimethylaminoethoxyethanol, and the remainder is water as a solvent; The reaction conditions were: temperature 30℃ and pressure 8kPa.
[0061] The measured data are shown in Table 1.
[0062] Table 1: Total Sulfur Removal Rate in Coke Oven Gas
[0063] The total sulfur removal rate is obtained by chromatography, which analyzes the sulfur content at the inlet (raw gas) and outlet (purified gas) of the coke oven gas desulfurization tower. The total time from the inlet to the outlet of the coke oven gas after purification is generally 30-60 seconds.
[0064] As shown in Table 1, Example 1, which did not add sulfolane, and Example 2, which did not add any active substances, had relatively low organic sulfur removal rates, with a total sulfur removal rate of only about 50%. In contrast, the composite solvents used in Examples 3-10 achieved very high organic sulfur removal rates from coke oven gas, with average total sulfur removal rates exceeding 80%. The total sulfur content of the purified gas was lower than the national ultra-low emission standard (35 mg / Nm³). 3 The equipment can be directly supplied to downstream production units without secondary processing.
[0065] The organic sulfur selective absorbent of the present invention has a high absorption rate for organic sulfur but a low absorption rate for other organic compounds (benzene compounds, phenols, naphthalene, various hydrocarbons, etc.). Therefore, it can selectively absorb organic sulfur and avoid the adverse effects of other organic compounds on the solvent. In particular, sulfolane can selectively absorb and remove CS2 and COS, and has a very high absorption rate for CS2 and COS because sulfolane (C4H8O2S) has a similar polarity to CS2 and COS.
[0066] Although sulfolane has a very high absorption rate for CS2 and COS, its absorption rate is relatively slow. Furthermore, in the water phase, CS2 and COS in the gas phase cannot fully contact sulfolane due to the water barrier, further hindering its absorption rate. By adding an active substance, on the one hand, the active substance can act as a bridge connecting the organic sulfur in the gas phase and the organic sulfur selective absorbent in the aqueous solution, thus eliminating the water barrier effect. On the other hand, diisopropanolamine in the active substance has a certain degree of alkalinity and physical solubility for acidic gases, and can enhance the absorption efficiency of the organic sulfur selective absorbent for acidic components through Henry's Law. Meanwhile, tetraethylene glycol dimethyl ether in the active substance acts as a phase transfer catalyst, promoting heterogeneous reactions (i.e., it can capture CS2 and COS from the gas phase into the organic sulfur selective absorbent), and because it also has weak alkalinity, it has the ability to selectively absorb acidic gases, thereby accelerating the absorption rate of CS2 and COS by sulfolane. Therefore, under normal temperature and low pressure, the composite organic solvent of the present invention can efficiently remove total sulfur from coke oven gas within 30-60 seconds.
[0067] The specific process for removing CS2, COS, and thiols from coke oven gas using the composite organic solvent provided by this invention is as follows: The composite organic solvent undergoes counter-current gas-liquid contact with coke oven gas inside the desulfurization tower; Organic sulfur selective absorbents in composite organic solvents, under the action of active substances... It can quickly select absorb After absorption, CS2, COS, and thiols undergo rapid hydrolysis with water under the catalysis of an organic sulfur selective absorbent to produce hydrogen sulfide and carbon dioxide. Hydrogen sulfide and carbon dioxide further react with methyldiethanolamine in the desulfurization tower to form amine salts, thereby efficiently removing CS2, COS, and thiols from blast furnace gas. Sulfolane exhibits selective absorption and removal of CS2 and COS from organic sulfur compounds, with extremely fast adsorption rates. Methyl monoethanolamine selectively absorbs and removes thiols from organic sulfur compounds.
[0068] The reaction mechanism between organic sulfur and complex organic solvents is as follows: CS2 + 2H2O = 2H2S + CO2 COS + H2O = H2S + CO2 The reaction mechanism between inorganic sulfur and complex organic solvents is as follows: Hydrogen sulfide and carbon dioxide react with methyldiethanolamine to form amine salts, and the reactions are reversible. H2S+ CH3N(CH2CH2OH)2 [(HOCH2CH2)2N + HCH3] H , CO2 + H2O + 2CH3N(CH2CH2OH)2 [(HOCH2CH2)2N + HCH3]2 CO3 2 .
[0069] Furthermore, coke oven gas, besides having a high total sulfur content and a more complex sulfide composition than blast furnace gas, also contains many other organic compounds, such as benzene series compounds, phenols, naphthalene, and various hydrocarbons. These complex organic compounds can affect the solvent system, especially benzene series compounds and phenols, which can be adsorbed by the solvent and produce unknown chemical reactions similar to floating substances in oil. This application uses a solvent that selectively absorbs and removes organic sulfur compounds, thus avoiding the adverse effects of these organic compounds on the solvent.
[0070] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A composite organic solvent for removing organic sulfur from coke oven gas, characterized in that, Includes organic sulfur selective absorbents, active substances, and water; The organic sulfur selective absorbent is configured to selectively absorb the organic sulfur; The active substance is configured to accelerate the absorption rate of the organic sulfur by the selective organic sulfur absorbent. The organic sulfur selective absorbent has a weight percentage of 76 wt% and 89 wt%, and the active substance has a weight percentage of 1.5 wt% and 2 wt%.
2. The composite organic solvent as described in claim 1, characterized in that, The organic sulfur selective absorbent includes sulfolane.
3. The composite organic solvent as described in claim 2, characterized in that, The weight percentage of sulfolane is greater than or equal to 38 wt% and less than or equal to 42 wt%.
4. The composite organic solvent as described in claim 1, characterized in that, The organic sulfur selective absorber includes methyldiethanolamine.
5. The composite organic solvent as described in claim 4, characterized in that, The weight percentage of the methyldiethanolamine is greater than or equal to 38 wt% and less than or equal to 42 wt%.
6. The composite organic solvent as described in claim 1, characterized in that, The organic sulfur selective absorber includes methyl monoethanolamine.
7. The composite organic solvent as described in claim 6, characterized in that, The weight percentage of the methyl monoethanolamine is less than or equal to 5 wt%.
8. The composite organic solvent as described in claim 1, characterized in that, The active substance includes diisopropanolamine.
9. The composite organic solvent as described in claim 8, characterized in that, The weight percentage of the diisopropanolamine is greater than or equal to 1 wt% and less than or equal to 1.5 wt%.
10. The composite organic solvent as described in claim 1, characterized in that, The active substance includes tetraethylene glycol dimethyl ether.
11. The composite organic solvent as described in claim 10, characterized in that, The weight percentage of the tetraethylene glycol dimethyl ether is less than or equal to 0.5 wt%.
12. The application of a composite desulfurization organic solvent in the removal of organic sulfur from coke oven gas, characterized in that, The composite desulfurization organic solvent is the composite organic solvent for removing organic sulfur as described in any one of claims 1-11, wherein the organic sulfur comprises CS2.
13. The application as described in claim 12, characterized in that, The CS2 accounts for more than or equal to 50% of the organic sulfur.
14. The application as described in claim 12, characterized in that, Its features are, The organic sulfur also includes COS and thiols.
15. The application as described in claim 13, characterized in that, The COS accounts for more than or equal to 30% of the organic sulfur.
16. The application as described in claim 12, characterized in that, Its features are, The organic sulfur mentioned is organic sulfur found in coke oven gas.
17. The application as described in claim 16, characterized in that, The temperature of the coke oven gas shall not exceed 50°C.
18. The application as described in claim 16, characterized in that, The pressure of the coke oven gas is ultra-low pressure.
19. The application as described in claim 16, characterized in that, The ultra-low pressure is less than or equal to 8 kPa.
20. The application as described in claim 16, characterized in that, The composite desulfurization organic solvent is used in the desulfurization process before coke oven gas.