For non-precious metal catalyst and preparation method thereof and the application of hydrocarbon isomerization
Technical field
The present invention relates to a kind of non-precious metal catalyst for hydrocarbon isomerization and preparation method thereof and application, specifically relate to a kind of with have non-precious metal catalyst that larger Extra specific surface area sum prepared for carrier compared with the SAPO-11 molecular sieve of peracidity, this catalyst preparation method and utilize this catalyst to carry out the method for the hydrocarbon isomerization particularly two branched chain isomerization reaction of hydro carbons.
Background technology
Hydrocarbon isomerization is one of most important catalytic conversion process in petrochemical industry, can be applicable to all many-sides such as the viscosity temperature characteristic improving the octane number of gasoline, the pour point of reduction diesel oil and improve lube base oil.In recent years, the research and development of hydrocarbon isomerization technology are made more and more to receive the concern of people to the continuous increase of high-quality oil product demand.Only for the production of high-quality motor petrol, highly-branched chain isomerous alkane is the best blend component that high-quality cleans in motor petrol, make the alkene in gasoline or full close after the n-alkane isoparaffin that is converted into two side chain or highly branched chain be the best means improving octane number, exploitation have highly active hydro carbons isomery particularly two branched chain isomer catalyst production tool that is clean and ultra-clean motor petrol is of great significance.
Current, the hydrocarbon isomerization catalyst of industrial employing is bifunctional catalyst, namely be made up of the molecular sieve with acid function and the metal two parts with hydrogenation-dehydrogenation function, as the hydrocarbon isomerization catalyst disclosed in by US Patent No. P5057471 and USP8198501.Although these catalyst have advantage clearly, also there is the selective shortcoming such as low of serious, the two branched chain isomerization of cracking reaction.Therefore, need the hydrocarbon isomerization catalyst of development of new badly, especially possess the catalyst of the two branched chain isomer function of hydro carbons.
Silicon phosphate aluminium profiles (SAPO) molecular sieve is the novel non-zeolitic molecular sieves of a class that U.S. combinating carbide company invented in 1984, receives extensive attention in catalytic field.SAPO-n replaces AlPO by Si atom
4formed after P or Al atom in-n skeleton by AlO
4, PO
4and SiO
4the non-neutral framework of molecular sieve that tetrahedron is formed.SAPO-11 molecular sieve is as a member in SAPO-n type molecular sieves, be the molecular sieve for hydrocarbon isomerization of most study in recent ten years, the acidity of its special pore passage structure and gentleness gives the hydrocarbon isomerization performance of the catalyst excellence being carrier with it.
At present, research for SAPO-11 molecular sieve based catalyst is devoted to improve catalyst to the isomerisation selectivity of hydro carbons more, and do not focus on fecund high-octane pair of branched chain isomer alkane, as Chinese patent application 02136301.3 (publication number CN1392099A).Therefore, improve the process of octane number if be applied to by these SAPO-11 molecular sieves, the isomerization product generated is the not too high single branched chain isomer of octane number, and the higher two branched chain isomer output of octane number are less.In addition, SAPO-11 molecular sieve coordinates precious metals pt to use mostly, and noble metal be not suitable for sour product, and cost is also higher.Therefore, urgently develop and not only there is the two branched chain isomer function of excellent hydro carbons, but also there is the SAPO-11 molecular sieve based catalyst of resistance to sulfur functional.
Summary of the invention
One object of the present invention is for the problem in above-mentioned prior art existing for hydrocarbon isomerization catalyst, there is provided a kind of there is larger external surface area and the non-precious metal catalyst prepared for carrier compared with the New type of S APO-11 molecular sieve of peracidity, to overcome the shortcoming that current hydrocarbon isomerization noble metal catalyst cost is high, sulfur tolerance is poor.
Another object of the present invention is to the preparation method that described non-precious metal catalyst is provided.
Another object of the present invention is to provide the application of described non-precious metal catalyst in the isomerization reaction of catalysis hydro carbons.
Another object of the present invention is to provide a kind of hydrocarbon isomerization method applying described non-precious metal catalyst.
For reaching above-mentioned purpose, on the one hand, the invention provides a kind of hydrocarbon isomerization non-precious metal catalyst, this catalyst is prepared from the supported carrier base metal active component of SAPO-11 molecular sieve, wherein:
Described SAPO-11 molecular sieve external surface area 200-280m
2/ g, in strong
acid acid amount 120-200 μm of ol/g;
Described base metal active component is selected from two kinds in Ni, Mo, W, Co, with the gross weight of catalyst for benchmark, with the oxide basis of activity component metal, in catalyst in active component content 5 ~ 20wt%(the present invention, except indicating especially, described content and ratio are weight content and ratio).
According to preferred specific embodiments of the present invention, in catalyst of the present invention, described base metal active component is one of Ni-Mo, Ni-W or Ni-Co combination.With the oxide basis of activity component metal, the content of metal active constituent Ni is 3-6%, Mo, the content of W or Co is 5-8%.
According to double-function catalyzing reaction mechanism, the collaborative coupling between the acid function of molecular sieve and the hydrogenation-dehydrogenation function of metal is the key obtaining excellent hydrocarbon isomerization catalyst.Inventor, to this has been large quantifier elimination, finally proposes catalyst of the present invention.
Two branched chain isomers of hydro carbons are owing to having larger volume, it can only generate at the outer surface of SAPO-11 molecular sieve, and the conventional SAPO-11 molecular sieve of prior art due to crystallite dimension larger, external surface area is very little, the place that can generate for two branched chain isomer is limited, thus only has quite limited two branched chain isomerization active.Meanwhile, the acidity that SAPO-11 is more weak is also unfavorable for the generation of two branched chain isomer.
According to specific embodiment of the invention scheme, the present invention SAPO-11 used molecular sieve has different characterisitic parameters from conventional SAPO-11 molecular sieve, its external surface area 200-280m
2/ g, in strong
acid acid amount 120-200 μm of ol/g.For making SAPO-11 molecular sieve, there is larger external surface area, compared with peracidity to meet needs of the present invention, the synthetic method of the present invention to SAPO-11 molecular sieve is improved.Particularly, have larger external surface area described in of the present invention, be employing two sections of crystallization method synthesis compared with the SAPO-11 molecular sieve of peracidity, its concrete preparation process comprises:
(1) phosphorus source, aluminium source, water, di-n-propylamine and Organic Alcohol are pressed (0.5-2.5): 1:(20-50): (0.7-2.0): the mol ratio (by oxide basis) of (0.1-50) mixes mutually, after stirring, carry out crystallization 3-8h in 130-180 DEG C, form precursor sol;
(2) in precursor sol, add cationic surfactant, organosilicon source, or add suitable quantity of water further, through stir, aging after at 160-200 DEG C crystallization 20-40h;
(3) solid product is separated, washing, dry and under the air atmosphere of 400-650 DEG C roasting 4-8 hour, obtain SAPO-11 molecular sieve.
According to preferred specific embodiments of the present invention, in the process of above-mentioned preparation SAPO-11 molecular sieve, described cationic surfactant is DTAB (DoTAB).Preferably, the addition of this cationic surfactant is that in itself and system, the mol ratio in aluminium source is (0.001-0.003): 1.
According to specific embodiment of the invention scheme, the preparation method of described SAPO-11 molecular sieve of the present invention, in second segment crystallization (above-mentioned steps (2)) process, organosilicon source described in preferred controlling crystallizing system: aluminium source: phosphorus source: di-n-propylamine: Organic Alcohol: surfactant (DoTAB): the mol ratio of water is (0.1-2.0): 1:(0.5-2.5): (0.7-2.0): (0.1-50): (0.001-0.003): (20-60).
In the preparation method of described SAPO-11 molecular sieve of the present invention, the mol ratio in described organosilicon source, aluminium source and phosphorus source is respectively with SiO
2, Al
2o
3and P
2o
5meter.
According to specific embodiment of the invention scheme, in the preparation process of described SAPO-11 molecular sieve of the present invention, the selection in the phosphorus source in raw material, aluminium source and organosilicon source can for the raw material generally adopted in prior art, and the present invention is not particularly limited.Such as, phosphorus source can be phosphoric acid, phosphorous acid, and aluminium source can be boehmite, aluminium isopropoxide, and organosilicon source can be ethyl orthosilicate, positive silicic acid propyl ester etc.In the preparation process of described SAPO-11 molecular sieve of the present invention, it is identical that wherein said Organic Alcohol and described organosilicon source are hydrolyzed the alcohol generated.
According to preferred specific embodiments of the present invention, of the present invention there is larger external surface area, prepare in accordance with the following methods compared with the SAPO-11 molecular sieve of peracidity:
(1) phosphorus source, aluminium source and water are mixed by certain mol ratio, and stir in the water bath with thermostatic control of 30 ~ 40 DEG C; Add di-n-propylamine and Organic Alcohol again, load in stainless steel autoclave that liner is polytetrafluoroethylene (PTFE) after mixing and stirring, under the self-generated pressure of 130 ~ 180 DEG C, hydrothermal crystallizing 3 ~ 8h forms precursor sol; Wherein, the mol ratio of phosphorus source in the hierarchy of control, aluminium source, water, di-n-propylamine and Organic Alcohol is (0.5-2.5): 1:(20-50): (0.7-2.0): (0.1-50);
(2) in the precursor sol being cooled to room temperature, quantitative cationic surfactant, organosilicon source and water is added, continue to stir until form uniform gel, and aging 10-34h is left standstill at 55 ~ 65 DEG C, afterwards, this gel is loaded in stainless steel autoclave, under the self-generated pressure of 185-200 DEG C, hydrothermal crystallizing 20-30h, obtains solid product; Wherein, in the hierarchy of control, the mol ratio of organosilicon source, aluminium source, phosphorus source, di-n-propylamine, Organic Alcohol, surfactant (DoTAB), water is (0.1-2.0): 1:(0.5-2.5): (0.7-2.0): (0.1-50): (0.001-0.003): (20-60);
(3) taken out the solid product that obtain, through cooling, centrifugation washing, to neutral, put into baking oven temperature at 120 DEG C and are dried, and in the Muffle furnace of 500-650 DEG C high-temperature roasting 5-8h, obtain SAPO-11 zeolite product.
In the skeleton forming process of SAPO-11, first phosphorus aluminium be combined to form electroneutral AlPO
4-11 skeletons, silicon enters skeleton in two ways afterwards: 1 Si replaces a P; 2 Si replace 1 Al and 1 P, make original electroneutral molecular sieve be provided with tradable electric charge, form acidic site.According to specific embodiment of the invention scheme, in the synthesis of SAPO-11 molecular sieve, adopt two sections of crystallization and the rear mode introducing silicon source can make more Si atom be distributed in the surface of SAPO-11 molecular sieve, thus produce the acidic site contacted more, make in prepared SAPO-11 molecular sieve strong
acid acid amount is 120-200 μm of ol/g, and this value is far longer than in the SAPO-11 molecular sieve prepared by prior art strong
sour value; The introducing of cationic surfactant then can play peptizaiton, and inventor's investigation and comparison peptizaiton of multiple cationic surfactant, find wherein with the cationic surfactant of main chain with 12 carbon atoms, particularly the peptizaiton of DTAB of the present invention to SAPO-11 molecular sieve precursor crystallite is maximum, this greatly reduces the crystallite dimension of SAPO-11 molecular sieve, thus makes the external surface area of SAPO-11 molecular sieve increase to 200-280m
2/ g is even larger.
According to specific embodiment of the invention scheme, in order to avoid metal active constituent poison by impurity such as S, N, As, the present invention adopts base metal as hydrogenation-dehydrogenation active component.Single with regard to metal component, the prerequisite of selection possesses enough hydrogenation-dehydrogenation performances.The d track of the catalytic activity of metal and its atom is closely related, and employing d percentage (d%) carrys out the d electronic state in quantitative expression metallic atom usually.D% is larger, and the electronics that in corresponding metallic atom, d can be with is filled more, then d electron hole is fewer, and the degree of d electron hole affects the absorption of metal and the key of catalytic performance.Adsorption capacity may cause Irreversible Adsorption too by force, and the too weak activated reactant molecule that is not enough to of adsorption capacity, therefore need the adsorption capacity of metal moderate.For hydrogenation catalyst, d%=40 ~ 50% is best.Obtaining in the various base metal active components of commercial Application at present, the d%=40% of the d%=43% of the d%=43% of the d%=40% of Ni, Mo, W, Co.Therefore, in the preparation process in accordance with the present invention, wherein two kinds in this several base metal are adopted.
The catalyst be prepared into the supported carrier base metal active component of SAPO-11 molecular sieve of the present invention can be described as SAPO-11 molecular screen base non-precious metal catalyst, it can be used as hydrocarbon isomerization catalyst and uses, not only can overcome the shortcoming that current noble metal catalyst cost is high, sulfur tolerance is poor, higher two branched chain isomerization can also be obtained selective.
On the other hand, present invention also offers the preparation method of described SAPO-11 molecular screen base non-precious metal catalyst, the method comprising the steps of:
(1) described SAPO-11 molecular sieve, boehmite and sesbania powder mixed and ground, adding peptizing agent dilute nitric acid solution afterwards, extruded moulding is also dry, obtains solid carrier;
(2) prepare the maceration extract of Ni and Mo, W or Co, adopt equi-volume impregnating base metal active component (such as Ni-Mo, Ni-W or Ni-Co) to be impregnated on dry solid carrier;
(3) dry for the solid product obtained after dipping non-noble metal components, roasting can be obtained the catalyst for the two branched chain isomer of hydro carbons of the present invention.
In the preparation method of above-mentioned SAPO-11 molecular screen base non-precious metal catalyst of the present invention, described in step (1), boehmite and sesbania powder are respectively as binding agent and extrusion aid, the conventional amount used in field belonging to its consumption adopts, the amount preferably controlling SAPO-11 molecular sieve in final preparation-obtained catalyst in the present invention is in the final preparation-obtained catalyst of 50 ~ 80wt%(, except the oxide of described base metal active component and SAPO-11 molecular sieve, all the other are binding agent mainly).
In the preparation method of above-mentioned SAPO-11 molecular screen base non-precious metal catalyst of the present invention, the maceration extract of Ni, Mo, W and Co can adopt Ni (NO respectively
3)
2, (NH
4)
6moO
24, (NH
4)
6h
2w
12o
40with Co (NO
3)
2solution.Two kinds of active components preferably impregnated on carrier in the mode of total immersion stain by incipient impregnation simultaneously.
In the preparation method of SAPO-11 molecular screen base non-precious metal catalyst of the present invention, the concrete operations do not mentioned in detail (comprise acid-soluble, the extruded moulding in carrier preparation process, drying, and flooded the process such as drying, roasting of catalyst of active component) routine operation in affiliated field can be adopted, such as, described drying can be after placing 4 ~ 14h at normal temperatures, dry 2 ~ 6h at 80 ~ 140 DEG C; Roasting 2 ~ 6h at described roasting condition is generally 400 ~ 800 DEG C.
On the other hand, present invention also offers the application of described SAPO-11 molecular screen base non-precious metal catalyst in catalysis the hydrocarbon isomerization particularly two branched chain isomerization reaction of hydro carbons.The reaction of described hydro carbons two branched chain isomerization can be such as two branched chain isomerization reactions of normal octane; Two branched chain isomerization reactions of normal heptane; Two branched chain isomerization of the true gasoline that two branched chain isomerization of positive octene are reacted and comprised various straight chain hydrocarbon are reacted.
On the other hand, present invention also offers a kind of hydrocarbon isomerization method applying described non-precious metal catalyst.The method mainly uses non-precious metal catalyst of the present invention as the catalyst of the hydrocarbon isomerization particularly two branched chain isomerization reaction of hydro carbons.During concrete enforcement, preferably controlling isomerization reaction condition in the present invention is: reaction pressure 1-2MPa, weight (hourly) space velocity (WHSV) (WHSV) 1.5-3.5h
-1, reaction temperature 593-723K, hydrogen-oil ratio (n (H2)/n (oil)) 300-500.Catalyst need through presulfurization process before the reaction, and sulfurized oil is for containing 3wt%CS
2normal octane solution.Conditions of vulcanization is: pressure (P)=2.8MPa, weight (hourly) space velocity (WHSV) (WHSV)=2.0h
-1, temperature (T)=613K, hydrogen-oil ratio [n (H
2)/n (oil)]=300.After catalyst preprocessing process completes, device is transferred to P=1-2MPa, WHSV=1.5-3.5h
-1, T=593-723K, n (H
2the isomerization reaction condition of)/n (oil)=300-500, opens sampling valve, pumps into raw material and reacts, and namely usual charging 3h reaction stablizes.
Compared with prior art gained hydrocarbon isomerization catalyst, non-precious metal catalyst provided by the present invention is utilized to carry out hydrocarbon isomerization, not only can overcome the shortcoming that current noble metal catalyst cost is high, sulfur tolerance is poor, higher two branched chain isomerization can also be obtained selective.
Accompanying drawing explanation
Fig. 1 is NiMo/SAPO-11-T-D catalyst, the NiW/SAPO-11-T-D catalyst of embodiment 2 preparation and the X ray diffracting spectrum of conventional SAPO-11 molecular sieve prepared by the embodiment of the present invention 1.
Detailed description of the invention
Introduce realization and the feature of technical solution of the present invention in detail below in conjunction with specific embodiment, to help to understand Spirit Essence of the present invention and beneficial effect, but can not form can any restriction of practical range to the present invention.
The synthesis (T represents two sections of crystallization method synthesis, and D represents cationic surfactant DoTAB) of embodiment 1NiMo/SAPO-11-T-D catalyst
First, two sections of crystallization method synthesis SAPO-11 molecular sieves are adopted: take 13.6g phosphoric acid, 9.0g boehmite (containing 70.3%Al
2o
3) and 30.0g deionized water, stir in the water bath with thermostatic control of 35 DEG C; Slowly add 7.6g di-n-propylamine and 11.3g propyl alcohol successively with vigorous stirring; Load in stainless steel autoclave that liner is polytetrafluoroethylene (PTFE) after mixing and stirring, under the self-generated pressure of 160 DEG C, hydrothermal crystallizing 6h forms precursor sol; The positive silicic acid propyl ester of 0.06g DoTAB, 5.0g and 10.0g water is added in the colloidal sol being cooled to room temperature, continue to stir until form uniform gel, and aging 24h is left standstill at 60 DEG C, afterwards, this gel is loaded in stainless steel autoclave, under the self-generated pressure of 185 DEG C, hydrothermal crystallizing 24h, obtains solid product; Finally taken out by the solid product obtained, through cooling, centrifugation is also washed to neutral, puts into baking oven in 120 DEG C of oven dry, obtains SAPO-11 molecular screen primary powder; By SAPO-11 molecular screen primary powder high-temperature roasting 6h in the Muffle furnace of 600 DEG C, obtaining external surface area is 241m
2/ g, in strong
acid acid amount is the SAPO-11-T-D molecular sieve of 153.6 μm of ol/g.
SAPO-11-T-D molecular sieve, boehmite and sesbania powder are mixed and grind, adds appropriate dilute nitric acid solution afterwards, after extruded moulding, dry supervisor, impregnating metal component.The dipping of metal component adopts the method for incipient impregnation, and maceration extract is Ni (NO
3)
2(NH
4)
6moO
24mixed solution, by oxide basis, pickup is respectively Ni4wt%, Mo6wt%.Namely NiMo/SAPO-11-T-D catalyst is obtained through dry, roasting supervisor after dipping.The X ray diffracting spectrum of this catalyst as shown in Figure 1.
The synthesis (C represents the synthesis of conventional crystallization method, and D represents cationic surfactant DoTAB) of comparative example 1NiMo/SAPO-11-C-D catalyst
First, one section of conventional crystallization method synthesis SAPO-11 molecular sieve is adopted: 40.0g deionized water and 13.6g phosphoric acid are mixed to form colloidal sol in 35 DEG C of water-baths; Add 9.0g boehmite, stir 90min, then add the positive silicic acid propyl ester of 5.0g and 0.06g DoTAB, continue to stir 120min, more slowly add template di-n-propylamine 7.6g, continue to stir, until form uniform initial gel mixture; Load above-mentioned initial gel mixture with in teflon-lined stainless steel cauldron, crystallization 24h at 185 DEG C, obtains solid product; By solid product separation, washing, 120 DEG C of dryings, roasting 6h at 600 DEG C, obtains SAPO-11 molecular sieve.
Afterwards, SAPO-11 molecular sieve, boehmite and sesbania powder are mixed and grind, adds appropriate dilute nitric acid solution, after extruded moulding, dry supervisor, impregnating metal component.The dipping of metal component adopts the method for incipient impregnation, and maceration extract is Ni (NO
3)
2(NH
4)
6moO
24mixed solution, by oxide basis, pickup is respectively Ni4wt%, Mo6wt%.Namely NiMo/SAPO-11-C-D catalyst is obtained through dry, roasting supervisor after dipping.
The pore structure data of catalyst prepared in embodiment 1 and comparative example 1 are as shown in table 1, and acid characterization result is as shown in table 2.
The pore structure parameter of the catalyst in table 1 embodiment 1 and comparative example 1
As seen from Table 1, compared with conventional hydrothermal synthetic method, DoTAB auxiliary under, adopt that the SAPO-11 synthesized by two sections of crystallization methods is catalyst based the larger mesoporous pore volume of Extra specific surface area sum, this is attributable under two sections of crystal patterns, the dispersiveness of DoTAB makes prepared SAPO-11 molecular sieve have less crystallite dimension, and the external surface area significantly increased derives from the reduction of zeolite crystal size just.
The acid amount (calculating according to pyridine-IR Characterization result) of the catalyst in table 2 embodiment 1 and comparative example 1
As seen from Table 2, compared with conventional hydrothermal synthetic method, the SAPO-11 synthesized by two sections of crystallization methods is catalyst based have more can be used for isomerized in strong
acid position.
With n-C
8for model compound, the isomerization reaction performance that the SAPO-11 obtained by having investigated is catalyst based, evaluate and carry out in continuous fixed bed reactors, the loadings of catalyst is 3g.Catalyst needs through presulfurization process before evaluation, and sulfurized oil is for containing 3wt%CS
2normal octane solution.Conditions of vulcanization is: pressure (P)=2.8MPa, weight (hourly) space velocity (WHSV) (WHSV)=2.0h
-1, temperature (T)=613K, hydrogen-oil ratio [n (H
2)/n (oil)]=300.After catalyst preprocessing process completes, device is transferred to following evaluation response condition: reaction pressure 1.5MPa, reaction temperature 340 DEG C, hydrogen alkane volume ratio 400:1, weight (hourly) space velocity (WHSV) 1.5h
-1, open sampling valve, pump into raw material and react, after charging 3h stable reaction, collect condensed fluid product, adopt chromatography to analyze product.Evaluation result is in table 3.
N-C on catalyst in table 3 embodiment 1 and comparative example 1
8isomerization reaction result
? |
NiMo/SAPO-11-T-D |
NiMo/SAPO-11-C-D |
Conversion ratio (%) |
83.6 |
81.9 |
Single branched chain isomer C
8Selective (%)
|
65.6 |
74.7 |
Two branched chain isomer C8 selective (%) |
32.1 |
6.7 |
Cracking Selectivity (%) |
1.8 |
13.6 |
To compare n-C
8isomerization reaction result can find, with the NiMo/SAPO-11-T-D catalyst prepared by method provided by the invention, compared with the NiMo/SAPO-11-C-D catalyst prepared with conventional method, have the Cracking Selectivity that higher two branched chain isomers are selective and lower, this has more strong owing to the catalyst prepared by the present invention
acid position and larger external surface area.
The synthesis (T represents two sections of crystallization method synthesis, and D represents cationic surfactant DoTAB) of embodiment 2, NiCo/SAPO-11-T-D catalyst
First, two sections of crystallization method synthesis SAPO-11 molecular sieves are adopted: take 15.2g phosphoric acid, 9.0g boehmite (containing 70.3%Al
2o
3) and 47.0g deionized water, stir in the water bath with thermostatic control of 35 DEG C; Slowly add 4.6g di-n-propylamine and 2.9g propyl alcohol successively with vigorous stirring; Load in stainless steel autoclave that liner is polytetrafluoroethylene (PTFE) after mixing and stirring, under the self-generated pressure of 160 DEG C, hydrothermal crystallizing 6h forms precursor sol; The positive silicic acid propyl ester of 0.02g DoTAB, 13.8g and 10.0g water is added in the colloidal sol being cooled to room temperature, continue to stir until form uniform gel, and aging 24h is left standstill at 60 DEG C, afterwards, this gel is loaded in stainless steel autoclave, under the self-generated pressure of 185 DEG C, hydrothermal crystallizing 24h, obtains solid product; Finally taken out by the solid product obtained, through cooling, centrifugation is also washed to neutral, puts into baking oven in 120 DEG C of oven dry, obtains SAPO-11 molecular screen primary powder; By SAPO-11 molecular screen primary powder high-temperature roasting 6h in the Muffle furnace of 600 DEG C, obtaining external surface area is 252m
2/ g, in strong
acid acid amount is the SAPO-11-T-D molecular sieve of 159.3 μm of ol/g.
Afterwards, SAPO-11-T-D molecular sieve, boehmite, sesbania powder and dilute nitric acid solution are mixed, after extruded moulding, dry supervisor, impregnating metal component.Maceration extract is Ni (NO
3)
2with Co (NO
3)
2mixed solution, by oxide basis, pickup is respectively Ni3wt%, Co10wt%.Namely NiCo/SAPO-11-T-D catalyst is obtained through dry, roasting supervisor after dipping.
The synthesis (T represents two sections of crystallization method synthesis, and C represents cationicsurfactants) of comparative example 2-1, NiCo/SAPO-11-T-C catalyst
In example 2, just change cationic surfactant DoTAB into softex kw (CTAB), all the other components are constant with operation, obtained NiCo/SAPO-11-T-C catalyst.
The synthesis (T represents two sections of crystallization method synthesis) of comparative example 2-2, NiCo/SAPO-11-T catalyst
First prepare SAPO-11-T molecular sieve, concrete preparation method is identical with embodiment 2, just in the synthesis of molecular sieve, does not introduce cationic surfactant DoTAB.Afterwards, NiCo/SAPO-11-T catalyst is obtained through preparation procedure similarly to Example 2.
The pore structure data of catalyst prepared in embodiment 2 and comparative example 2-1, comparative example 2-2 are as shown in table 4, and acid characterization result is as shown in table 5.
The pore structure parameter of the catalyst in table 4 embodiment 2 and comparative example 2-1, comparative example 2-2
As seen from Table 4, with do not introduce compared with cationic surfactant, under cationic surfactant is auxiliary, adopt that the SAPO-11 synthesized by two sections of crystallization methods is catalyst based the larger mesoporous pore volume of Extra specific surface area sum, this is attributable to the peptizaiton of cationic surfactant, make prepared SAPO-11 molecular sieve have less crystallite dimension, and the external surface area increased derive from the reduction of zeolite crystal size just.Meanwhile, compared with CTAB, the dispersiveness of DoTAB is stronger, makes the external surface area of obtained SAPO-11 molecular sieve maximum, brings unforeseeable significant technique effect.
The acid amount (calculating according to pyridine-IR Characterization result) of the catalyst in table 5 embodiment 2 and comparative example 2-1, comparative example 2-2
As seen from Table 5, have the SAPO-11 of maximum external surface area catalyst based have more can be used for isomerized in strong
acid position.
With n-C
8for model compound, the isomerization reaction performance that the SAPO-11 obtained by having investigated is catalyst based, evaluate and carry out in continuous fixed bed reactors, the loadings of catalyst is 3g.Catalyst needs through presulfurization process before evaluation, and sulfurized oil is for containing 3wt%CS
2normal octane solution.Conditions of vulcanization is: pressure (P)=2.8MPa, weight (hourly) space velocity (WHSV) (WHSV)=2.0h
-1, temperature (T)=613K, hydrogen-oil ratio [n (H
2)/n (oil)]=300.After catalyst preprocessing process completes, device is transferred to following evaluation response condition: reaction pressure 1.5MPa, reaction temperature 400 DEG C, hydrogen alkane volume ratio 350:1, weight (hourly) space velocity (WHSV) 1.5h
-1, open sampling valve, pump into raw material and react, after charging 3h stable reaction, collect condensed fluid product, adopt chromatography to analyze product.Evaluation result is in table 6.
N-C on catalyst in table 6 embodiment 2 and comparative example 2-1, comparative example 2-2
8isomerization reaction result
Relatively n-C
8isomerization reaction result can find, with having larger external surface area and more polyoxybiontic NiCo/SAPO-11-T catalyst prepared by method provided by the invention, has the Cracking Selectivity that higher two branched chain isomers are selective and lower.
The synthesis of embodiment 3, NiW/SAPO-11-T-D catalyst
First, adopt two sections of crystallization method synthesis SAPO-11-T-D molecular sieves, concrete preparation method is identical with described in embodiment 1.Afterwards, SAPO-11 molecular sieve, boehmite, sesbania powder and dilute nitric acid solution are mixed, after extruded moulding, dry supervisor, impregnating metal component.Maceration extract is Ni (NO
3)
2(NH
4)
6h
2w
12o
40mixed solution, by oxide basis, pickup is respectively Ni3.5wt%, W7wt%.Namely NiW/SAPO-11-T catalyst is obtained through dry, roasting supervisor after dipping.The X ray diffracting spectrum of this catalyst as shown in Figure 1.
The synthesis of comparative example 3, Pt/SAPO-11-T-D catalyst
Change the maceration extract in embodiment 2 into H
2ptCl
6, by oxide basis, the load capacity of Pt is 0.5wt%.All the other operations are all identical with embodiment 2, obtain Pt/SAPO-11-T catalyst.
With true catalytically cracked gasoline for reaction raw materials, the isomerization reaction performance that the SAPO-11 obtained by having investigated is catalyst based, evaluate and carry out in continuous fixed bed reactors, the loadings of catalyst is 4g.Catalyst needs through presulfurization process before evaluation, and sulfurized oil is for containing 3wt%CS
2normal octane solution.Conditions of vulcanization is: pressure (P)=2.8MPa, weight (hourly) space velocity (WHSV) (WHSV)=2.0h
-1, temperature (T)=613K, hydrogen-oil ratio [n (H
2)/n (oil)]=300.After catalyst preprocessing process completes, device is transferred to following evaluation response condition: reaction pressure 1.5MPa, reaction temperature 320 DEG C, hydrogen alkane volume ratio 400:1, weight (hourly) space velocity (WHSV) 1.5h
-1, open sampling valve, pump into raw material and react, after charging 3h stable reaction, collect condensed fluid product, adopt chromatography to analyze product.Evaluation result is in table 7.
Table 7 raw material composition and plant running 20h, 50h and 100h after reaction result
As shown in Table 7, the NiW/SAPO-11-T-D catalyst prepared by embodiment 3 is after having run 100h, and isoparaffin on average adds 7.64%, shows good stability; And the Pt/SAPO-11-T catalyst prepared by comparative example 3 is after operation 50h, namely isomerization ability has downward trend, and running time is longer, the inactivation of catalyst is more obvious, this be due to sulphur be combined with precious metals pt after cover its surface, make Pt metal center inactivation, namely compare, catalyst Sulfur tolerance prepared in embodiment is stronger
Can find out through comparative example, the non-precious metal catalyst developed in the present invention not only has excellent hydrocarbon isomerization performance, and shows good stability and Sulfur tolerance, is expected to become hydrocarbon isomerization catalyst of new generation.