Coke oven gas hydrodesulfurization catalyst and preparation method thereof

Abstract

The invention belongs to the technical field of catalysts, and relates to a coke oven gas hydrodesulfurization catalyst and a preparation method thereof.The preparation method comprises the following steps that S1, a mixed solution is prepared from molybdenum salt, ferric salt and a compound containing acid radicals of A, then the mixed solution is kneaded with aluminum hydroxide powder, and a catalyst modified carrier is obtained through roasting; and S2, preparing a mixed solution from molybdenum salt and nickel salt, dipping the catalyst modified carrier obtained in the step S1, and roasting to obtain the coke oven gas hydrodesulfurization catalyst. In the use process, Mo in the carrier is gradually diffused to the surface of the catalyst to supplement lost Mo, so that the service life of the catalyst is prolonged; besides, F, P, S, B, As and the like are used for modifying the carrier, so that the acidity of the surface of the catalyst carrier can be enhanced, the interaction between the carrier and loaded molybdenum oxide can be weakened, the dispersity and the sulfuration degree of the molybdenum oxide on the surface can be improved, and the activity of the catalyst can be further improved.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a coke oven gas hydrodesulfurization catalyst and its preparation method. Background Technology

[0002] Coke oven gas is rich in essential components such as H2, CH4, CO, CO2, C2H4, and C2H6, giving it significant application value. After purification, coke oven gas can be used as a raw material for the synthesis of methanol, natural gas, and ammonia. However, coke oven gas contains various harmful impurities, including trace amounts of H2S, COS, CS2, thiophene, mercaptans, and sulfides, which can poison and deactivate subsequent catalysts. Therefore, coke oven gas desulfurization is a crucial process for its purification and utilization.

[0003] Currently, coke oven gas hydrodesulfurization generally uses Fe-Mo / γ-Al2O3 catalysts, but their activity is low. Even at operating temperatures of 350℃~420℃, the removal rate of organic sulfur is only about 60%, which is difficult to meet the requirements of industrial use. On the other hand, conventional Co-Mo or Ni-Mo catalysts are thermally deactivated because the CO and CO2 contained in coke oven gas are prone to undergo strong exothermic reactions such as methanation.

[0004] Chinese invention patent CN 101797513A discloses a coke oven gas hydrodesulfurization catalyst obtained by using γ-Al₂O₃ or MgO-Al₂O₃ as a support, loading a mixed solution of Mo-Fe-Ni-P salts, and then drying and calcining it. The invented catalyst is said to effectively improve the low-temperature activity of the catalyst, reduce side reactions such as methanation, and extend the catalyst's lifespan. However, since the active component is loaded onto the support surface only once, the problem of loss of the active component Mo is not well addressed. Chinese invention patent CN 108855116B discloses a coke oven gas hydrodesulfurization catalyst obtained by kneading, extruding, drying, and calcining a mixed solution of Mo-Fe-Ni with boehmite. This catalyst is said to effectively reduce the methanation reaction activity; however, to reduce methanation activity, the amount of active component Mo is significantly reduced, sacrificing hydrodesulfurization activity. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention provides a coke oven gas hydrodesulfurization catalyst and its preparation method, which can effectively reduce Mo loss and extend catalyst life, as well as reduce the methanation reaction rate.

[0006] The specific plan is as follows:

[0007] A coke oven gas hydrodesulfurization catalyst, using Al2O3 as a support, supports active components MoO3, NiO, Fe2O3, and an acid anion containing A; wherein, the content of MoO3 accounts for 1-25 wt% of the total catalyst, the content of NiO accounts for 0.01-6 wt% of the total catalyst, the content of Fe2O3 accounts for 0.5-10 wt% of the total catalyst, the content of the acid anion containing A accounts for 0.05-5 wt% of the total catalyst, and the balance is Al2O3; A is selected from at least one of F, P, S, B, As, and Sb.

[0008] A method for preparing a coke oven gas hydrodesulfurization catalyst includes the following steps:

[0009] S1 is prepared by mixing molybdenum salt, iron salt, and a compound containing an acid radical A, then kneading it with aluminum hydroxide powder, and calcining it to obtain a catalyst-modified support.

[0010] S2. A mixed solution of molybdenum salt and nickel salt is prepared, and then the catalyst-modified support obtained in step S1 is impregnated and calcined to obtain a coke oven gas hydrodesulfurization catalyst.

[0011] Furthermore, in step S1, the calcination temperature is 500~700℃ and the calcination time is 1~20h.

[0012] Furthermore, in step S2, the calcination temperature is 400~600℃ and the calcination time is 1~20h.

[0013] Furthermore, the amount of Mo moles in the molybdenum salt in step S1 accounts for 5 to 50% of the total amount of Mo moles in the molybdenum salts in steps S1 and S2.

[0014] Preferably, the molybdenum salt is selected from at least one of ammonium molybdate, ammonium tetramolybdate, and ammonium paramolybdate; the iron salt is selected from at least one of soluble iron salts, preferably ferric nitrate, ferric chloride, ferric sulfate, and ferric acetate; the compound containing the A anion is selected from at least one of acid or ammonium salt; and the nickel salt is selected from at least one of soluble nickel salts, preferably nickel nitrate, nickel chloride, nickel sulfate, and nickel acetate.

[0015] Preferably, the aluminum hydroxide powder in step S1 is boehmite.

[0016] The beneficial effects of this invention are as follows:

[0017] Studies have shown that one of the main reasons for the deactivation of coke oven gas hydrodesulfurization catalysts is the loss of the active component Mo. This invention divides the active component Mo into two parts: one part is prepared as a modified support by extrusion with iron salts and modifier A and pseudoboehmite; the other part is loaded onto the support surface by impregnation with nickel salts. The advantages are that during use, Mo in the support gradually diffuses to the catalyst surface to replenish the lost Mo, extending the catalyst's lifespan. Furthermore, by modifying the support with F, P, S, B, As, etc., the acidity of the catalyst support surface can be enhanced, the interaction between the support and the supported molybdenum oxide can be weakened, and the dispersibility and sulfidation degree of the surface molybdenum oxide can be improved, thereby increasing the catalyst activity. Detailed Implementation

[0018] The embodiments of the present invention will be described in further detail below. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0019] Example 1

[0020] A method for preparing a coke oven gas hydrodesulfurization catalyst includes the following steps:

[0021] S1 Weigh 10g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 20g ferric nitrate nonahydrate Fe(NO3)3·9H2O, 2g ammonium fluoride NH4F, and 100mL deionized water were dissolved to obtain a mixed transparent solution. Then, 200g of boehmite was added and kneaded evenly. The mixture was then extruded into strips, dried at 120℃ for 10h, and calcined at 600℃ for 5h to obtain a catalyst-modified support.

[0022] S2 Weigh 25g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 5g nickel nitrate hexahydrate Ni(NO3)2·6H2O, were dissolved in 50mL of deionized water to obtain a mixed transparent solution. The above modified support was added and impregnated for 5h, then dried at 110℃ for 10h, and calcined at 500℃ for 5h to obtain the catalyst.

[0023] The catalyst uses Al2O3 as a support and supports active components MoO3, NiO, Fe2O3, and fluoride ions; wherein, the content of MoO3 accounts for 17.3 wt% of the total catalyst, the content of NiO accounts for 0.779 wt% of the total catalyst, the content of Fe2O3 accounts for 2.40 wt% of the total catalyst, the content of fluoride ions accounts for 0.623 wt% of the total catalyst, and the balance is Al2O3.

[0024] Example 2

[0025] A method for preparing a coke oven gas hydrodesulfurization catalyst includes the following steps:

[0026] S1 Weigh 10g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 20g of ferric nitrate nonahydrate Fe(NO3)3·9H2O, 3g of ammonium phosphate (NH4)3PO4, and 100mL of deionized water were dissolved to obtain a mixed transparent solution. Then, 200g of boehmite was added and kneaded evenly. The mixture was then extruded into strips, dried at 120℃ for 10h, and calcined at 600℃ for 5h to obtain a catalyst-modified support.

[0027] S2 Weigh 25g of ammonium molybdate (NH4)6Mo7O 24 10g of nickel nitrate hexahydrate Ni(NO3)2·6H2O was dissolved in 50mL of deionized water to obtain a mixed transparent solution. The above modified support was added and impregnated for 5h, then dried at 110℃ for 10h, and calcined at 550℃ for 5h to obtain the catalyst.

[0028] The catalyst uses Al2O3 as a support and supports active components MoO3, NiO, Fe2O3, and phosphate ions. The content of MoO3 accounts for 17.1 wt% of the total catalyst, the content of NiO accounts for 1.54 wt% of the total catalyst, the content of Fe2O3 accounts for 2.37 wt% of the total catalyst, the content of phosphate ions accounts for 1.15 wt% of the total catalyst, and the balance is Al2O3.

[0029] Example 3

[0030] A method for preparing a coke oven gas hydrodesulfurization catalyst includes the following steps:

[0031] S1 Weigh out 15g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 25g ferric nitrate nonahydrate Fe(NO3)3·9H2O, 1g ammonium fluoride NH4F, 5g ammonium phosphate (NH4)3PO4, and 100mL deionized water were dissolved to obtain a mixed transparent solution. Then, 200g of boehmite was added and kneaded evenly. The mixture was then extruded into strips, dried at 120℃ for 10h, and calcined at 600℃ for 5h to obtain a catalyst-modified support.

[0032] S2 Weigh 20g of ammonium molybdate (NH4)6Mo7O 24 8g of nickel nitrate hexahydrate Ni(NO3)2·6H2O was dissolved in 50mL of deionized water to obtain a mixed transparent solution. The above modified support was added and impregnated for 5h, then dried at 110℃ for 10h, and calcined at 550℃ for 10h to obtain the catalyst.

[0033] The catalyst uses Al2O3 as a support and supports active components MoO3, NiO, Fe2O3, as well as fluoride ions and phosphate ions. The content of MoO3 accounts for 16.9 wt% of the total catalyst content, the content of NiO accounts for 1.21 wt% of the total catalyst content, the content of Fe2O3 accounts for 2.92 wt% of the total catalyst content, the total amount of fluoride ions and phosphate ions accounts for 2.19 wt% of the total catalyst content, and the balance is Al2O3.

[0034] Example 4

[0035] A method for preparing a coke oven gas hydrodesulfurization catalyst includes the following steps:

[0036] S1 Weigh out 15g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 10g ferric nitrate nonahydrate Fe(NO3)3·9H2O, 5g ammonium sulfate (NH4)2SO4, and 100mL deionized water were dissolved to obtain a mixed transparent solution. Then, 200g of pseudoboehmite was added and kneaded evenly. The solution was then extruded into strips, dried at 120℃ for 10h, and calcined at 550℃ for 5h to obtain a catalyst-modified support.

[0037] S2 Weigh 20g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 5g nickel nitrate hexahydrate Ni(NO3)2·6H2O, were dissolved in 50mL of deionized water to obtain a mixed transparent solution. The above modified support was added and impregnated for 5h, then dried at 110℃ for 10h, and calcined at 550℃ for 5h to obtain the catalyst.

[0038] The catalyst uses Al2O3 as a support and supports active components MoO3, NiO, Fe2O3, and sulfate ions. The content of MoO3 accounts for 17.3 wt% of the total catalyst, the content of NiO accounts for 0.776 wt% of the total catalyst, the content of Fe2O3 accounts for 1.20 wt% of the total catalyst, the total amount of sulfate ions accounts for 2.20 wt% of the total catalyst, and the balance is Al2O3.

[0039] Comparative Example 1

[0040] Weigh out 35g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 20g ferric nitrate nonahydrate Fe(NO3)3·9H2O, 10g nickel nitrate hexahydrate Ni(NO3)2·6H2O, 3g ammonium phosphate (NH4)3PO4, and 60mL deionized water were dissolved to obtain a mixed transparent solution. 130g of γ-Al2O3 support was added and impregnated for 5h, then dried at 110℃ for 10h, and calcined at 550℃ for 5h to obtain the catalyst.

[0041] Comparative Example 2

[0042] Weigh out 35g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 20g of ferric nitrate nonahydrate Fe(NO3)3·9H2O, 10g of nickel nitrate hexahydrate Ni(NO3)2·6H2O, and 100mL of deionized water were dissolved to obtain a mixed transparent solution. 200g of boehmite was added and kneaded evenly. The solution was then extruded into strips, dried at 120℃ for 10h, and calcined at 550℃ for 5h to obtain the catalyst.

[0043] Comparative Example 3

[0044] S1 Weigh out 35g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 20g ferric nitrate nonahydrate Fe(NO3)3·9H2O, 2g ammonium fluoride NH4F, and 100mL deionized water were dissolved to obtain a mixed transparent solution. Then, 200g of boehmite was added and kneaded evenly. The mixture was then extruded into strips, dried at 120℃ for 10h, and calcined at 600℃ for 5h to obtain a catalyst-modified support.

[0045] S2 Weigh 5g of nickel nitrate hexahydrate Ni(NO3)2·6H2O, dissolve it in 50mL of deionized water to obtain a mixed transparent solution, add the above modified support and impregnate for 5h, then dry at 110℃ for 10h, and calcine at 500℃ for 5h to obtain the catalyst.

[0046] Comparative Example 4

[0047] Weigh out 35g of ammonium molybdate (NH4)6Mo7O 24 ·4H2O, 20g ferric nitrate nonahydrate Fe(NO3)3·9H2O, 2g ammonium fluoride NH4F, 5g nickel nitrate hexahydrate Ni(NO3)2·6H2O, and 100mL deionized water were dissolved to obtain a mixed transparent solution. Then, 200g of boehmite was added and kneaded evenly. The solution was then extruded into strips, dried at 120℃ for 10h, and calcined at 600℃ for 5h to obtain the catalyst.

[0048] test

[0049] The catalysts prepared according to the embodiments and comparative examples of the present invention were applied to the hydrodesulfurization reaction of coke oven gas in a fixed-bed reactor with a catalyst loading of 10 mL and a gas space velocity of 1000 h⁻¹. -1 The reaction temperature was 300℃. The simulated coke oven gas composition (V / V) was: H2 60%, N2 10%, CO 7%, CO2 3%, CH4 20%, and total sulfur: 100 mg / m³. 3 H2S 50mg / m 3 CS2 25mg / m 3 C4H4S 25mg / m 3After continuous reaction for 10 hours, the initial desulfurization rate and methanation amount were obtained. Then, the reaction temperature was raised to 550℃ to accelerate catalyst deactivation. After 10 hours of deactivation, the temperature was lowered to 300℃ and the reaction was continued for 10 hours to obtain the desulfurization rate and methanation amount after catalytic deactivation. The results are shown in Table 1.

[0050] Table 1 Comparison of catalytic results

[0051]

[0052] The above data demonstrate that the catalyst of this invention has high activity, low methanation rate, and significantly better stability than the comparative catalyst.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A catalyst for hydrodesulfurization of coke oven gas, characterized in that, The catalyst uses Al2O3 as a support and supports active components MoO3, NiO, Fe2O3 and an acid radical containing A; wherein A is selected from at least one of F, P, S, B, As, and Sb.

2. The coke oven gas hydrodesulfurization catalyst according to claim 1, characterized in that, The content of MoO3 is 1-25 wt% of the total catalyst, the content of NiO is 0.01-6 wt% of the total catalyst, the content of Fe2O3 is 0.5-10 wt% of the total catalyst, the content of acid radicals containing A is 0.05-5 wt% of the total catalyst, and the balance is Al2O3.

3. The preparation method of the coke oven gas hydrodesulfurization catalyst as described in claim 1, characterized in that, Includes the following steps: S1 is prepared by mixing molybdenum salt, iron salt, and a compound containing an acid radical A, then kneading it with aluminum hydroxide powder, and calcining it to obtain a catalyst-modified support. S2. A mixed solution of molybdenum salt and nickel salt is prepared, and then the catalyst-modified support obtained in step S1 is impregnated and calcined to obtain a coke oven gas hydrodesulfurization catalyst.

4. The preparation method according to claim 3, characterized in that, In step S1, the calcination temperature is 500~700℃ and the calcination time is 1~20h.

5. The preparation method according to claim 3, characterized in that, In step S2, the calcination temperature is 400~600℃ and the calcination time is 1~20h.

6. The preparation method according to claim 3, characterized in that, The molar amount of Mo in the molybdenum salt in step S1 accounts for 5 to 50% of the total molar amount of Mo in the molybdenum salts in steps S1 and S2.

7. The preparation method according to claim 3, characterized in that, The molybdenum salt is selected from at least one of ammonium molybdate, ammonium tetramolybdate, and ammonium paramolybdate; the iron salt is selected from at least one of soluble iron salts; the compound containing an acid radical is selected from at least one of acid or ammonium salts; and the nickel salt is selected from at least one of soluble nickel salts.

8. The preparation method according to claim 3, characterized in that, In step S1, the aluminum hydroxide powder is boehmite.

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