CN1306885A - Method of synthesizing medium-pore holecular sieve MCM-41 and preparing hydrogenatino and desulfurization catalyst with MCM-41 as carrier - Google Patents

Abstract

The development of deeply hydrogenation and desulfurization catalyst is the key of producing gasoline and diesel oil with extremely low sulfur content. The present invention proposes one method of synthesizing MCM-41 medium pore molecular sieve and MCM-41 molecular sieve carried Mo-Co-Ni hydrogenation and desulfurization catalyst. Hydrothermally synthesized solid material is treated in nitrogen atmosphere at 600 deg.c for 12 hr before roast; cobalt or nickel nitrate and ammonium molybdate are dissolved in deionized water and MCM-41 is added while stirring for 2 hr; and through 24 hr stagnation, drying and roast, oxidation state catalyst is prepared.

Description

It is the method for preparing carriers Hydrobon catalyst that a kind of synthetic mesoporous molecular sieve MCM-41 reaches with it

The invention belongs to the Hydrobon catalyst that uses in synthetic a kind of petroleum refining, specially refer to a kind of MCM-41 mesoporous molecular sieve synthetic method and be that the molybdenum that the mesoporous molecular sieve of representative is made preparing carriers is the deep hydrodesulfurizationof catalyst with MCM-41.

In order to control SO effectively _xDischarging, reduce vehicle exhaust to atmosphere pollution, many countries have carried out strict control to the sulfur content in the fuel oil.And the present world can adopt crude oil and begin to present inferiorization trend, and sulfur content in crude oil increases.Thereby the oil refining industry is faced with at cost and increases a difficult problem that how to reduce the product oil sulfur content under the little prerequisite.According to people's such as Whitehurst analysis, the sulfur content standard is brought up to＜500ppm from＜2500ppm, if adopt conventional catalyst then reaction velocity must be decreased to original 1/4[Whitehurst, D.D., Isoda, T., and Mochida, I., Adv.Catal., 42,345,1998].Obviously, increase the volume of high-pressure reactor or to reduce output significantly all be unpractical.Therefore, exploitation deep hydrodesulfurizationof catalyst just becomes the key that solves this difficult problem.

Contain multiple sulfur-containing compound in the crude oil, its complexity that removes also difference is very big.In crude oil, main sulfur-containing compound has mercaptan, thiophene, benzothiophene, dibenzothiophenes and alkyl substituent thereof.Wherein, mercaptan is odorant, and the method for available oxidation removes fully.Other sulfur-containing compounds remove with the method for hydrogenation usually.The concentration of these sulfur-containing compounds is successively decreased by the order of thiophene, benzothiophene and dibenzothiophenes in the crude oil, and the difficulty during hydrogenation and removing increases in this order.γ-Al commonly used ₂O ₃Co-that supports or Ni-Mo effective catalyst can remove thiophene-based and the benzothiophene kind sulfur-containing compound in the crude oil fully.Because the content of dibenzothiophenes is very low in the crude oil, although such catalyst is very low to the removal efficiency of dibenzothiophenes, also can satisfy the requirement of sulfur content＜2500ppm.But,, then must remove condensed ring sulfur-containing compounds such as dibenzothiophenes class if further reduce the sulfur content of product oil.Structural analysis and result of study all show, the most difficult the removing of dibenzothiophenes class in these fused ring compounds.Because the above sulfur-containing compound in Fourth Ring is easy to the hydrogenation reaction of aromatic ring takes place and makes its structural distortion, the steric hindrance of the sulphur on the thiphene ring near the activity of such catalysts center time diminishes, and is easy to remove.In the dibenzothiophenes class,,, these two positions increase the inaccessible activated centre of the sulphur atom on the thiphene ring because being replaced the rear space steric hindrance by alkyl again with 4 and 6 the most difficult removing that replaced by alkyl.Therefore, the research of deep hydrodesulfurizationof catalyst is mainly with dibenzothiophenes (DBT), 4-MDBT (4-MDBT) and 4, and (4, hydrogenation reaction 6-DMDBT) is as probe reaction for the 6-dimethyl Dibenzothiophene.

The research and development of deep hydrodesulfurizationof catalyst are promptly screened than Co-or component that Ni-Mo is and W system activity is high and the carrier replacement γ-Al that develops function admirable generally from the expansion of two aspects ₂O ₃People such as Pecoraro [Pecoraro, T.A., Chianelli, R.R., J.Catal., 67,430,1981] screen transient metal sulfide, and they find that the hydrodesulfurization performance of metal sulfides such as Ru is better than W, Mo, Ni and Co.But they are supported on γ-Al ₂O ₃Or FSM-16 activity is but used not as industry when going up W system and Mo series catalysts [Ishihara, A, Nomura, M., and Kabe, T., J.Catal., 150,212,1994; Sugioka, M., Andalaluna, L., Morishita, L., and Kurosaka, T., Catal.Today, 39,61,1997].That studied at present removes γ-Al ₂O ₃Outer carrier has active carbon, TiO ₂, y-type zeolite and MCM-41 mesoporous molecular sieve etc.According to reports, these carriers can both improve activity of such catalysts to a certain extent.People such as Reddy and Song [Reddy, K.M., Wei, B., and Song, C.,, Catal.Today, 43 (3-4), 261,1998; Song, C.S., and Reddy, K.M., Appl.Catal., A, 176 (1), 1,1999] support catalyst that Co-Mo and Ni-Mo make with Al-MCM-41 and the hydrogenation activity of DBT is higher than uses the γ-Al that makes with quadrat method ₂O ₃Make the catalyst of carrier, but not as good as industrial deep desulfurization catalyst.Sugioka, Klimova[Klimova, T., Ramirez, J., Calderon, M., andDominguez, J.M., Stud.Surf.Sci Catal., Vol.117, pp 493,1998] and Yue[Yue, Y., Sun, Y., Xu, Q., and Gao, Z, Appl.Catal., A, 175 (1-2), 131,1998] though etc. the people to have developed Mo with mesoporous molecular sieve (FSM-16, MCM-41 and Al-MCM-41) as carrier be Hydrobon catalyst, they do not investigate the hydrogenation activity of DBT class at the thiophene hydrogenation reaction.

The present invention proposes the synthetic method of a kind of high-specific surface area, high thermal stability MCM-41, and makes the method that supported carrier Mo, Ni-Mo and Co-Mo prepare light oil (being specially adapted to diesel oil) deep hydrodesulfurizationof catalyst with synthetic MCM-41.

People such as Beck [Beck, J.S., Vartuli, J.C., Roth, W.J., Leonowicz, M.E., Kresge, C.T., Schmitt, K.D., Chu, C.T-W., Olson D.H..Sheppard, E.W., McCullen, S.B., Higgins, J.B., and Schlenker, J.L., J.Am.Chem.Soc., 114,10834,1992] characteristic and the synthetic method of MCM-41 molecular sieve have been reported first in 1992.Its synthetic method is similar to traditional synthesis method of zeolite molecular sieve, comprises promptly that the preparation, hydro-thermal of reaction mother liquor (silicon gel+template agent) is synthetic, steps such as filtration, washing, drying and roasting.The present invention improves the preparation method of above-mentioned MCM-41, and promptly the synthetic solid material that obtains of hydro-thermal is first at N before roasting ₂Handled 12 hours in 600 ℃ in the atmosphere.The result of Chu Liing is the heat endurance that had both improved MCM-41 like this, has increased the specific area of MCM-41 simultaneously.Co-Mo/MCM-41 and Ni-Mo/MCM-41 Preparation of catalysts method adopt traditional co-impregnation: cobalt nitrate or nickel nitrate and ammonium molybdate are dissolved in the deionized water; In the solution that makes, add MCM-41; Stirred 2-3 hour, leave standstill 20-24 hour after, with the moisture evaporate to dryness; At 130 ℃ of dry 3-5 hours; In 550 ℃ of roastings 6 hours, make oxidized catalyst then.

Evaluation method to this catalyst is: 0.2 gram oxidized catalyst is placed fixed bed reactors, vulcanized 3 hours down in 400 ℃ of normal pressures with the hydrogen gas mixture that contains 5% hydrogen sulfide earlier, cool the temperature to the hydrodesulfurization reaction temperature then.Behind temperature stabilization, feed H ₂And be forced into 5MPa, and will contain the decahydronaphthalene solution of percentage by weight 1%DBT or contain percentage by weight 0.2%DBT+0.1%4-MDBT+0.1%4 with high-pressure metering pump, the decahydronaphthalene solution of 6-DMDBT imports reaction system, the beginning hydrodesulfurization reaction.Reaction temperature 260-360 ℃, weight space velocity (WHSV) is 56 hours ^-1After question response is stable, got a fluid sample every 20 minutes,, thereby try to achieve under this temperature catalyst the hydrogenation conversion of sulfur-containing compound with the residual quantity of sulfur-containing compound in gas-chromatography (Shimadzu GC-17A) analytic sample.

The prepared mesoporous molecular sieve of the present invention has very high-specific surface area (＞1000m ²/ g); Prepared catalyst has very high hydrogenation activity to the dibenzothiophenes class, and reaction result is as shown in table 1.As seen, the highest to the hydrogenation activity of DBT when Ni/Mo or Co/Mo atomic ratio are 0.75 for the catalyst of Ni-Mo/MCM-41 and two series of Co-Mo/MCM-41, DBT all can transformed more than 320 ℃.Thereby they are well behaved deep desulfurization catalyst.

Table 1 Ni-Mo/MCM-41 and Co-Mo/MCM-41 Hydrobon catalyst are to the conversion ratio of DBT

Catalyst	Conversion ratio, %
					????300℃	?320℃	?340℃	?360℃
	20wt％MoO 3/ MCM-41 Ni-Mo series aNi/Mo is than 0.25 0.50 0.75 1.00 1.20 Co-Mo series aCo/Mo is than 0.25 0.50 0.75 1.00	????32.1 ????81.6 ????91.4 ????99.1 ????96.7 ????89.7 ????88.7 ????94.3 ????93.2 ????95.0	?50.8 ?94.3 ?95.1 ?100 ?98.6 ?97.6 ?98.5 ?98.0 ?99.5 ?98.8	?72.5 ?98.3 ?98.5 ?100 ?99.1 ?98.7 ?99.0 ?98.6 ?100 ?99.2					?85.9 ?99.3 ?100 ?100 ?99.2 ?100

^aMoO on all catalyst ₃Loading be 20%

Fig. 1 is that Ni-Mo/MCM-41 (Ni/Mo=0.75) catalyst is to the temperature variant curve of the hydrogenation conversion of dibenzothiophenes compounds.

Implement side 1.52g Na ₂SiO ₃Be dissolved in the 250ml deionized water, use 6MH ₂SO ₄Solution is with Na ₂SiO ₃The pH of solution transfers to 10.5, and strong agitation 30 minutes at room temperature, makes gel.20g trimethyl cetyl ammonium bromide is dissolved in the 25g deionized water, and the solution of making adds in the aforementioned gel.Gel stirred after 2 hours, added in the stainless steel autoclave, placed 130 ℃ of baking ovens, carried out hydro-thermal reaction.Cessation reaction is also with being water-cooled to room temperature after 12 hours.Product separates after filtration, washes, 60 ℃ of dryings are after 6 hours, at N ₂In the stream in 600 ℃ the heating 12 hours, then in high temperature furnace in air in 550 ℃ of roastings 6 hours, the product that makes is MCM-41.The specific area that records this product with the nitrogen adsorption method is 1153m ²/ g.

Embodiment 2.With 22g Ni (NO ₃) ₂6H ₂O and 21g (NH ₄) ₆Mo ₇O ₂₄4H ₂O is dissolved in the 150g deionized water and makes solution.In solution, add the MCM-41 that 55g makes in embodiment 1, at room temperature stirred 2 hours, then water is steamed.The pressed powder that obtains 130 ℃ dry 4 hours down, then 550 ℃ of roastings 6 hours in air atmosphere, make the Ni/Mo atomic ratio and be 0.75 oxidized catalyst.This catalyst is making the sulphided state catalyst on the fixed bed reactors after sulfuration, and on this device evaluate catalysts to the hydrogenation activity of DBT and derivative thereof.The hydrogenation conversion of this catalyst towards heavy amount percentage 1%DBT sees Table 1.It is 0.2%DBT, 0.1%4-MDBT and 0.1%4 to contained percentage by weight in the decahydronaphthalene, and the hydrogenation conversion of 6-DMDBT as shown in Figure 1.

Embodiment 3.With 24g Co (NO ₃) ₂6H ₂O and 21g (NH ₄) ₆Mo ₇O ₂₄4H ₂O is dissolved in the 150g deionized water and makes solution.In solution, add the MCM-41 that makes in 55g the foregoing description 1, at room temperature stirred 12 hours, then water is steamed.The pressed powder that obtains is 130 ℃ of dryings 4 hours, then 550 ℃ of roastings 6 hours in air atmosphere, makes the Co/Mo atomic ratio and be 0.75 oxidized catalyst.This catalyst on the fixed bed reactors through the sulfuration after making the sulphided state catalyst, and this device on evaluate catalysts to the DBT hydrogenation activity.This catalyst hydrogenation conversion to 1%DBT under different temperatures sees Table 1.

Claims (2)

1. the method for a synthetic MCM-41 mesoporous molecular sieve, it is characterized in that with the synthetic solid material that obtains of hydro-thermal before roasting earlier in nitrogen atmosphere in 600 ℃ of high-temperature process 12 hours.

2. make supported carrier molybdenum, cobalt, nickel with the MCM-41 mesoporous molecular sieve and prepare the method that molybdenum is the deep hydrodesulfurizationof catalyst for one kind, it is characterized in that cobalt nitrate or nickel nitrate and ammonium molybdate are dissolved in the deionized water; In the solution that makes, add MCM-41, stirred 2-3 hour, leave standstill 20-24 hour after, with the moisture evaporate to dryness, at 130 ℃ of dry 3-5 hours,, make oxidized catalyst then in 550 ℃ of roastings 6 hours.

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