One-step synthesized complex iron desulfurizer and preparation method therefor and use thereof

Abstract

A one-step synthesized complex iron desulfurizer and a preparation method therefor and a use thereof, relating to the technical field of desulfurization. The preparation method comprises: adding aspartic acid, maleic anhydride, iron powder, and a transition metal salt into water, mixing uniformly, heating to a preset temperature, then slowly adding a mixed salt solution of ammonia water and an ammonium salt solution, heating to 120°C to 140°C after completion of the addition, maintaining the temperature for reaction, and carrying out solid-liquid separation to obtain a reaction solution; and adding a corrosion inhibitor and a stabilizer to the reaction solution, heating to 50°C to 70°C, introducing an oxidizing gas for oxidation, concentrating, and drying to obtain a complex iron desulfurizer. The provided method for one-step synthesis of the complex iron desulfurizer involves a simple process, significantly simplifies the process flow of producing the complex iron desulfurizer, and reduces energy consumption; the complex iron desulfurizer prepared by using the method has a high complex iron content, a low impurity content, and a stable structure; the iron ion loss rate is below 1% after repeated use; and the process is safe and reliable and is suitable for large-scale production and application.

Description

One-step synthesis of complex iron desulfurizer and its preparation method and application

[0001] This patent application claims priority to Chinese patent application No. CN202311389437.4 filed on October 25, 2023. The disclosure of the prior application is incorporated herein by reference in its entirety. Technical Field

[0002] The present application relates to the field of desulfurization technology, and in particular to a one-step synthetic complex iron desulfurizer, a preparation method thereof, and applications thereof. Background Art

[0003] The LO-CAT desulfurization process, developed by a US company, uses complex iron as a desulfurizer and has been widely used in the desulfurization industry. Commonly used complexing agents for complex iron desulfurizers include ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, and polyaspartic acid (PASP). Polyaspartic acid is a water-soluble polymer that is phosphorus-free, non-toxic, pollution-free, and completely biodegradable. It has a strong chelating ability for ions and has dual corrosion and scale inhibition properties, making it an excellent complexing agent for complex iron. Currently, polyaspartic acid complex iron desulfurizers are mostly obtained by complexing polyaspartate salts with iron or ferrous ion salts. Polyaspartic acid needs to be synthesized from multiple raw materials such as aspartic acid and maleic anhydride through steps such as polycondensation, alkaline hydrolysis, and neutralization. In other words, the synthesis of polyaspartic acid complex iron desulfurizers requires a multi-step reaction to synthesize polyaspartic acid before proceeding to the next step.

[0004] At present, polyaspartic acid complex iron desulfurizing agent is mainly obtained by two-step or multi-step reaction, that is, first synthesizing polyaspartic acid, and then reacting with iron salt to obtain polyaspartic acid complex iron desulfurizing agent. This process reaction step is cumbersome, the raw material type used is more, the synthesis cost is high, and the obtained complex iron desulfurizing agent has many impurities, low iron complexing amount, and unstable complexing effect, which makes its production application subject to certain restrictions. Therefore, it is necessary to develop a synthetic method for a complex iron desulfurizing agent with simple process, low cost, high iron complexing amount and few impurities. Technical issues

[0005] In view of the problems existing in the existing process for preparing complex iron desulfurizers, such as complex process, high cost, low iron complexation amount, high impurity content, etc., the present application provides a one-step synthesis complex iron desulfurizer and its preparation method and application. Technical Solutions

[0006] To solve the above technical problems, the technical solutions provided by this application are:

[0007] In a first aspect, the present application provides a one-step method for synthesizing a complex iron desulfurizer, comprising the following steps:

[0008] Add aspartic acid, maleic anhydride, iron powder and transition metal salt into water, mix well, heat to a preset temperature, slowly add a mixed salt solution of ammonia water and ammonium salt solution, heat to 120°C~140°C after addition, keep warm for reaction, separate solid and liquid to obtain a reaction solution;

[0009] Adding a corrosion inhibitor and a stabilizer to the reaction solution, raising the temperature to 50° C. to 70° C., introducing an oxidizing gas for oxidation, concentrating, and drying to obtain a complex iron desulfurizer;

[0010] Wherein, the adding time of the mixed salt solution is 3h~5h.

[0011] Furthermore, the transition metal salt includes at least one of manganese chloride, chromium chloride or nickel chloride.

[0012] The addition of the preferred transition metal salt can improve the ability of polyaspartic acid to complex iron ions, thereby improving the desulfurization effect of the prepared polyaspartic acid complexed iron desulfurizer.

[0013] In one embodiment, the mass ratio of aspartic acid, maleic anhydride, iron powder, transition metal salt and water is 100:60~130:50~90:0.1~0.9:50~200.

[0014] The preferred raw material ratio in this embodiment is conducive to promoting the full progress of the reaction and improving the conversion rate of aspartic acid.

[0015] In one embodiment, the preset temperature is 80°C~100°C.

[0016] Adding ammonia water and ammonium salt solution at 80℃~100℃ can ensure that the raw materials are mixed more fully, and preheating the raw materials to 80℃~100℃ can reduce the occurrence of side reactions and reduce the impurity content in the polyaspartic acid complex iron desulfurizer.

[0017] In one embodiment, the insulation reaction time is 2h~5h.

[0018] The preferred reaction time in this embodiment can increase the conversion rate of aspartic acid and reduce the occurrence of side reactions.

[0019] In one embodiment, the mass ratio of the iron powder, ammonia water and ammonium salt solution is 100:10~30:600~1000.

[0020] Specifically, the mass concentration of the ammonia water is 15% to 30%, and the ammonium salt solution is a saturated ammonium chloride solution.

[0021] The preferred amount of ammonia water and ammonium salt added in this embodiment can ensure that the iron powder and NH4 + Fully respond and reduce response costs.

[0022] In one embodiment, the corrosion inhibitor includes at least one of chromate, molybdate, tungstate, vanadate, orthophosphate or borate.

[0023] The above-mentioned salts in this application can be sodium salts, potassium salts or ammonium salts commonly used in the art, and the use of the above-mentioned salts commonly used in the art can achieve basically equivalent technical effects.

[0024] In one embodiment, the stabilizer comprises one or both of sorbitol and polyethylene glycol.

[0025] In one embodiment, the mass ratio of the aspartic acid, the corrosion inhibitor and the stabilizer is 100:0.7~1.3:1~3.

[0026] The preferred corrosion inhibitor, stabilizer and addition amount in this embodiment can improve the structural stability and corrosion inhibition effect of the prepared polyaspartic acid complex iron desulfurizer and increase the number of recycling times of the complex iron desulfurizer.

[0027] It should be noted that after the heat preservation reaction is completed, nitrogen is introduced into the reaction system for purging, and then solid-liquid separation is performed, and a corrosion inhibitor and a stabilizer are added to the obtained filtrate.

[0028] In one embodiment, the oxidation time is 30 min to 40 min.

[0029] Furthermore, the oxidizing gas may be air or oxygen, and air is preferred for safety and cost considerations.

[0030] Specifically, the oxidizing gas is introduced into the system by bubbling.

[0031] In a second aspect, the present application further provides a complex iron desulfurizer, which is prepared by the above-mentioned one-step synthesis method of the complex iron desulfurizer.

[0032] In a third aspect, the present application also provides the use of the above-mentioned complex iron desulfurizer in the desulfurization of coke oven gas.

[0033] The complex iron desulfurizer provided in this application can also be used in the desulfurization process of coal gas, biogas, etc. produced by sewage treatment plants, oil extraction, pharmaceutical factories, etc.

[0034] In a fourth aspect, the present application further provides a method for desulfurizing coke oven gas, comprising the following steps:

[0035] Dissolve the above-mentioned complex iron desulfurizer in water and adjust the pH to 8.5-9.0 to obtain a complex iron desulfurizer solution;

[0036] The complex iron desulfurizing agent solution is sprayed into the desulfurizing device from the top, and coke oven gas is introduced from the bottom of the desulfurizing device to perform desulfurization to obtain a desulfurized rich liquid;

[0037] regenerating the desulfurized rich liquid to obtain a desulfurized lean liquid;

[0038] After the desulfurized lean liquid is filtered, it is circulated into the desulfurization device to continue desulfurization. Beneficial effects

[0039] Compared with the prior art, the method for synthesizing a complex iron desulfurizer in one step provided by the present application uses iron powder and ammonium chloride instead of the iron salt and part of the ammonia water in the prior art as reaction raw materials. By utilizing the reaction of ammonium salt and iron powder under specific conditions, heat consumption is reduced and the conversion rate of aspartic acid is improved. At the same time, by controlling the addition time of ammonia water and ammonium salt solution, the occurrence of side reactions is effectively reduced, the content of impurities is reduced, and the iron complexation amount is effectively increased, which is 10% higher than the complex iron content in the polyaspartic acid complex iron prepared by the traditional process; in addition, by adding corrosion inhibitors and stabilizers, the stability of the molecular structure of the polyaspartic acid complex iron is effectively improved. The polyaspartic acid complex iron prepared by the present application is regenerated 10 times in the desulfurization cycle, and the iron ion loss rate is less than 1%. It has a high cycle service life and has broad application prospects in the field of desulfurization.

[0040] The complex iron desulfurizer prepared in the present application uses aspartic acid, maleic anhydride, iron powder, transition metal salt, ammonia water and ammonium salt as raw materials to obtain polyaspartic acid complex iron with low impurity content, stable complex structure and high complex iron content in one step, which effectively shortens the preparation time, greatly improves the production efficiency, and has low production cost, and can be produced on a large scale. It opens up a new process for the preparation and performance optimization of the complex iron desulfurizer and has broad application prospects.

[0041] The method for synthesizing a complex iron desulfurizer in one step provided in the present application has a simple process, greatly simplifies the process flow for producing the complex iron desulfurizer, has low energy consumption, and the prepared complex iron desulfurizer has a high complex iron content, a low impurity content, a stable structure, and an iron ion loss rate of less than 1% after repeated use. The process is safe and reliable, suitable for large-scale production and application, and has broad application prospects in the field of desulfurization. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is an infrared spectrum of iron polyaspartate prepared in Example 1 of the present application;

[0043] FIG2 is a schematic diagram of the process flow of coke oven gas desulfurization in an embodiment of the present application. Modes for Carrying Out the Invention

[0044] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0045] In order to better illustrate the present application, further examples are given below.

[0046] The iron ion content in the polyaspartic acid complexed iron in the following examples and comparative examples was determined using the total iron content method specified in the Environmental Protection Industry Standard of the People's Republic of China HJ / T 345-2007 "Water Quality - Determination of Iron - O-Phenanthroline Spectrophotometry (Trial)".

[0047] Example 1

[0048] A one-step method for synthesizing a complex iron desulfurizer comprises the following steps:

[0049] 100 kg of aspartic acid, 63 kg of maleic anhydride, 55 kg of iron powder, 0.61 kg of chromium chloride, and 180 kg of water were added to a reactor and stirred evenly. The mixture was then heated to 100°C. 15 kg of 20% aqueous ammonia and 400 kg of saturated ammonium chloride were mixed evenly and slowly added to the reactor over a period of 5 hours. After the additions were complete, the temperature was raised to 135°C and the reaction was maintained for 2 hours. Nitrogen was purged through the reactor for 10 minutes, followed by filter press. 0.9 kg of sodium molybdate and 1.7 kg of polyethylene glycol were added to the resulting filtrate. The temperature was maintained at 60°C, air was bubbled through the filtrate for 35 minutes, and the solution was concentrated until viscous. The filter cake was dried and pulverized to obtain a polyaspartic acid-complexed iron desulfurizer.

[0050] The total impurity content of aspartic acid, maleic anhydride and maleic acid in the polyaspartic acid complex iron desulfurizer was detected by high performance liquid chromatography and was less than 1%. The iron ion content in the polyaspartic acid complex iron desulfurizer was detected by spectrophotometry and was 28.73%.

[0051] The infrared spectrum of the polyaspartic acid complexed iron desulfurizer prepared in this example is shown in FIG1 . Analysis shows that the infrared spectrum is consistent with the characteristics of polyaspartic acid.

[0052] Example 2

[0053] A one-step method for synthesizing a complex iron desulfurizer comprises the following steps:

[0054] 100kg of aspartic acid, 100kg of maleic anhydride, 76kg of iron powder, 0.74kg of manganese chloride, and 130kg of water were added to a reactor and stirred evenly. The mixture was then heated to 80°C. 10kg of 15% ammonia water and 650kg of saturated ammonium chloride aqueous solution were mixed evenly and slowly added to the reactor over a period of 4 hours. After the addition was complete, the temperature was raised to 125°C and the reaction was maintained for 4 hours. Nitrogen was purged through the reactor for 10 minutes, followed by filter press. 0.8kg of sodium tungstate and 2.6kg of sorbitol were added to the resulting filtrate. The temperature was maintained at 50°C, air was bubbled through the filtrate for 40 minutes, and the solution was concentrated until the liquid became viscous. The filter press was then performed, and the resulting filter cake was dried and pulverized to obtain a polyaspartic acid complexed iron desulfurizer.

[0055] The total impurity content of aspartic acid, maleic anhydride and maleic acid in the polyaspartic acid complex iron desulfurizer was detected by high performance liquid chromatography and was less than 1%. The iron ion content in the polyaspartic acid complex iron desulfurizer was detected by spectrophotometry and was 27.96%.

[0056] Example 3

[0057] A one-step method for synthesizing a complex iron desulfurizer comprises the following steps:

[0058] 100kg of aspartic acid, 125kg of maleic anhydride, 90kg of iron powder, 0.1kg of manganese chloride, 0.1kg of nickel chloride, and 200kg of water were added to a reactor and stirred evenly. The mixture was then heated to 90°C. 9kg of 30% aqueous ammonia and 890kg of saturated ammonium chloride were mixed evenly and slowly added to the reactor over 4.5 hours. After the additions were complete, the temperature was raised to 120°C and the reaction was maintained for 5 hours. Nitrogen was purged through the reactor for 10 minutes, followed by filter press. 1.1kg of ammonium molybdate and 1.2kg of polyethylene glycol were added to the resulting filtrate. The temperature was maintained at 65°C, air was bubbled through the filtrate for 35 minutes, and the solution was concentrated until viscous. The filter cake was dried and pulverized to obtain a polyaspartic acid-complexed iron desulfurizer.

[0059] The total impurity content of aspartic acid, maleic anhydride and maleic acid in the polyaspartic acid complex iron desulfurizer was detected by high performance liquid chromatography and was less than 1%. The iron ion content in the polyaspartic acid complex iron desulfurizer was detected by spectrophotometry and was 28.39%.

[0060] Example 4

[0061] A one-step method for synthesizing a complex iron desulfurizer comprises the following steps:

[0062] 100kg of aspartic acid, 110kg of maleic anhydride, 75kg of iron powder, 0.9kg of chromium chloride, and 60kg of water were added to a reactor and stirred evenly. The mixture was then heated to 100°C. 20kg of 25% aqueous ammonia and 570kg of saturated ammonium chloride were mixed evenly and slowly added to the reactor over a period of 3 hours. After the additions were complete, the temperature was raised to 130°C and the reaction was maintained for 3 hours. Nitrogen was purged through the reactor for 10 minutes, followed by filter press. 0.7kg of sodium chromate and 2.2kg of sorbitol were added to the resulting filtrate. The temperature was maintained at 70°C, air was bubbled through the filtrate for 30 minutes, and the solution was concentrated until viscous. The filter cake was dried and pulverized to obtain a polyaspartic acid-complexed iron desulfurizer.

[0063] The total impurity content of aspartic acid, maleic anhydride and maleic acid in the polyaspartic acid complex iron desulfurizer was detected by high performance liquid chromatography and was less than 1%. The iron ion content in the polyaspartic acid complex iron desulfurizer was detected by spectrophotometry and was 28.04%.

[0064] Comparative Example 1

[0065] This comparative example provides a preparation method of a complex iron desulfurizer, which is different from Example 2 only in that no saturated ammonium chloride aqueous solution is added. The method specifically comprises the following steps:

[0066] 100kg of aspartic acid, 100kg of maleic anhydride, 76kg of iron powder, 0.74kg of manganese chloride, and 130kg of water were added to a reactor and stirred evenly. The mixture was then heated to 80°C. 10kg of 15% ammonia water was slowly added to the reactor over a 4-hour period. After addition, the temperature was raised to 125°C and the reaction was maintained for 4 hours. Nitrogen was purged through the reactor for 10 minutes, followed by filter press. 0.8kg of sodium tungstate and 2.6kg of sorbitol were added to the resulting filtrate. The temperature was maintained at 50°C, air was bubbled through the filtrate for 40 minutes, and the solution was concentrated until viscous. The filter cake was dried and pulverized to obtain a polyaspartic acid complexed iron desulfurizer.

[0067] The total impurity content of aspartic acid, maleic anhydride and maleic acid in the polyaspartic acid complex iron desulfurizer was 12.6% by high performance liquid chromatography. The iron ion content in the polyaspartic acid complex iron desulfurizer was 0.2% by spectrophotometry. The iron content was too low and the impurity content was too high, so it could not be used for desulfurization experiments.

[0068] Comparative Example 2

[0069] This comparative example provides a preparation method of a complex iron desulfurizer, which is different from Example 3 only in the addition time of ammonia water and saturated ammonium chloride aqueous solution, and specifically includes the following steps:

[0070] 100kg of aspartic acid, 125kg of maleic anhydride, 90kg of iron powder, 0.1kg of manganese chloride, 0.1kg of nickel chloride, and 200kg of water were added to a reactor and stirred thoroughly. The mixture was then heated to 90°C. 9kg of 30% aqueous ammonia and 890kg of saturated ammonium chloride were mixed thoroughly and slowly added to the reactor over a period of 1 hour. After the addition was complete, the temperature was raised to 120°C and the reaction was maintained for 5 hours. Nitrogen was purged through the reactor for 10 minutes, followed by filter press. 1.1kg of ammonium molybdate and 1.2kg of polyethylene glycol were added to the resulting filtrate. The temperature was maintained at 65°C, air was bubbled through the filtrate for 35 minutes, and the solution was concentrated until viscous. The filter cake was dried and pulverized to obtain a polyaspartic acid-complexed iron desulfurizer.

[0071] The total impurity content of aspartic acid, maleic anhydride and maleic acid in the polyaspartic acid complex iron desulfurizer was determined by high performance liquid chromatography and was found to be 27.1%. The iron ion content in the polyaspartic acid complex iron desulfurizer was determined by spectrophotometry and was found to be 14.16%. The impurity content was too high and the desulfurization experiment was not performed.

[0072] Comparative Example 3

[0073] This comparative example provides a preparation method of a complex iron desulfurizer, which is different from Example 1 only in that the saturated ammonium chloride aqueous solution is replaced with an equal amount of saturated aluminum chloride aqueous solution, and specifically comprises the following steps:

[0074] 100 kg of aspartic acid, 63 kg of maleic anhydride, 55 kg of iron powder, 0.61 kg of chromium chloride, and 180 kg of water were added to a reactor and stirred thoroughly. The mixture was then heated to 100°C. 15 kg of 20% aqueous ammonia and 400 kg of saturated aluminum chloride were mixed thoroughly and slowly added to the reactor over a period of 5 hours. After the additions were complete, the temperature was raised to 135°C and the reaction was maintained for 2 hours. Nitrogen was purged through the reactor for 10 minutes, followed by filter press. 0.9 kg of sodium molybdate and 1.7 kg of polyethylene glycol were added to the resulting filtrate. The temperature was maintained at 60°C, air was bubbling through the filtrate for 35 minutes, and the solution was concentrated until viscous. The solution was then filter press filtered, and the resulting filter cake was dried and pulverized to obtain a polyaspartic acid-complexed iron desulfurizer.

[0075] The total impurity content of aspartic acid, maleic anhydride and maleic acid in the polyaspartic acid complex iron desulfurizer was determined by high performance liquid chromatography and was found to be 25.80%. The iron ion content in the polyaspartic acid complex iron desulfurizer was determined by spectrophotometry and was found to be 0.3%. The iron content was too low and the impurity content was too high, so it could not be used for desulfurization experiments.

[0076] Desulfurization performance test

[0077] The desulfurization process flow for testing the desulfurization effect and stability of the polyaspartic acid complexed iron desulfurizer prepared in Examples 1-4 is shown in FIG2 .

[0078] The gas used is coke oven gas produced by conventional coking plant process, in which the H2S content is 5740mg / m 3 The coke oven gas is drawn out from the branch pipe of the gas pipeline which has been cooled to 30~40℃.

[0079] The polyaspartic acid complexed iron desulfurizer prepared in Examples 1-4 was added to water to prepare 60 L of polyaspartic acid complexed iron solution with a total iron ion concentration of 1000 mg / L, and the pH was adjusted to 8.5-9.0 with sodium carbonate and sodium bicarbonate. 3 / h rate from the bottom of the desulfurization tower, the prepared polyaspartic acid complex iron solution is sprayed into the desulfurization tower from the top, the feeding rate is 120L / h, and the temperature of the polyaspartic acid complex iron solution is controlled at 30~35℃. When the polyaspartic acid complex iron solution is sprayed, the coke oven gas is stopped, and the desulfurized rich liquid after desulfurization is transported from the bottom of the desulfurization tower to the regeneration tower (i.e., the regeneration tank in Figure 2) through the rich liquid pump, and regenerated by air aeration to make the desulfurizer have desulfurization capacity again. Among them, the air flow rate is 1m 3 / h. The regeneration tower temperature is controlled at 50-60°C by steam, and the regeneration time is 25-30 minutes. The regenerated desulfurized lean liquid is pumped to the plate and frame filter via a lean liquid pump for filtration to obtain a sulfur filter cake (sulfur paste). The filtrate is then circulated into the desulfurization tower via a filtrate pump for further desulfurization.

[0080] After 10 cycles of regeneration and desulfurization according to the above operation, the iron ion loss rate, sulfur capacity and desulfurization efficiency of the polyaspartic acid complex iron desulfurizer prepared in each example are shown in Table 1.

[0081] Among them, the iron ion loss rate

[0082] Wherein, h0 represents the iron ion content in the complex iron desulfurizer before desulfurization, in mg / L; h represents the iron ion content in the complex iron desulfurizer after desulfurization, in mg / L.

[0083] Desulfurization efficiency

[0084] In the above formula: c0 represents the initial hydrogen sulfide concentration in coke oven gas, unit: mg / m 3 ; c represents the concentration of hydrogen sulfide in the clean gas after desulfurization, in mg / m 3 .

[0085] Table 1

[0086] Iron ion loss rate Sulfur capacity (g / L) Desulfurization efficiency Example 1 0.53% 3.099.76% Example 2 0.75% 2.999.49% Example 3 0.71% 2.999.55% Example 4 0.62% 3.099.61%

[0087] In summary, the method for preparing a polyaspartic acid complexed iron desulfurizer provided in the present application has a simple process and high production efficiency. The prepared polyaspartic acid complexed iron desulfurizer has a high iron ion content and a low impurity content, which can effectively improve the desulfurization effect. The complex structure is stable and can be reused multiple times, effectively reducing the desulfurization cost and having high practical value.

[0088] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A one-step synthesis method of a complex iron desulfurizing agent, characterized in that: The steps include: Add aspartic acid, maleic anhydride, iron powder and transition metal salt into water, mix well, heat to a preset temperature, slowly add a mixed salt solution of ammonia water and ammonium salt solution, heat to 120°C~140°C after adding, keep warm for reaction, separate solid and liquid to obtain a reaction solution; Adding a corrosion inhibitor and a stabilizer to the reaction solution, raising the temperature to 50° C. to 70° C., introducing an oxidizing gas for oxidation, concentrating, and drying to obtain a complex iron desulfurizer; Wherein, the adding time of the mixed salt solution is 3h~5h; The mass ratio of aspartic acid, maleic anhydride, iron powder, transition metal salt and water is 100:60~130:50~90:0.1~0.9:50~200; the mass ratio of iron powder, ammonia water and ammonium salt solution is 100:10~30:600~1000, the mass concentration of ammonia water is 15%~30%, and the ammonium salt solution is a saturated ammonium chloride solution.

2. The method for synthesizing a complex iron desulfurizing agent in one step according to claim 1, characterized in that: The transition metal salt includes at least one of manganese chloride, chromium chloride or nickel chloride.

3. The one-step synthesis method of the complex iron desulfurizing agent according to claim 1, characterized in that: The preset temperature is 80°C to 100°C; and / or The insulation reaction time is 2h~5h.

4. The one-step synthesis method of the complex iron desulfurizing agent according to claim 1, characterized in that: The corrosion inhibitor comprises at least one of chromate, molybdate, tungstate, vanadate, orthophosphate or borate; and / or The stabilizer includes one or both of sorbitol and polyethylene glycol.

5. The method for synthesizing a complex iron desulfurizing agent in one step according to claim 1 or 4, characterized in that: The mass ratio of aspartic acid, corrosion inhibitor and stabilizer is 100:0.7-1.3:1-3; and / or The oxidation time is 30min~40min.

6. A complex iron desulfurizer, characterized in that: The desulfurizer is prepared by the one-step synthesis method of the complex iron desulfurizer according to any one of claims 1 to 5.

7. Use of the complex iron desulfurizer according to claim 6 in desulfurization of coke oven gas.

8. A method for desulfurizing coke oven gas, characterized in that: The steps include: Dissolving the complex iron desulfurizer according to claim 6 in water, adjusting the pH to 8.5-9.0, to obtain a complex iron desulfurizer solution; The complex iron desulfurizing agent solution is sprayed into the desulfurizing device from the top of the desulfurizing device, and coke oven gas is introduced from the bottom of the desulfurizing device to perform desulfurization to obtain a desulfurized rich liquid; regenerating the desulfurized rich liquid to obtain a desulfurized lean liquid; After the desulfurization lean liquid is filtered, it is circulated into the desulfurization device to continue desulfurization.

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