CN104828839B - The method for preparing small crystal grain Y-shaped molecular sieve - Google Patents

Abstract

The invention discloses a kind of preparation method of small crystal grain Y-shaped molecular sieve.This method is using the NaY type Molecular sieve raw materials that silica alumina ratio is higher, crystallinity is high, stability is good, sequentially pass through alkali cleaning, ammonium exchange, dealumination complement silicon, hydro-thermal process and with acid with after the processing of the mixed solution of ammonium salt, resulting small crystal grain Y-shaped molecular sieve is obtaining higher SiO₂/A1₂O₃While mol ratio, the ratio shared by secondary pore is higher, and maintains the stability of Y type molecular sieve, and molecular sieve has higher specific surface area and higher crystallinity.Y type molecular sieve obtained by the present invention can make catalyst have activity, middle distillates oil selectivity and excellent product property well suitably as the Cracking Component of the oily hydrocracking catalyst of senior middle school.

Description

The method for preparing small crystal grain Y-shaped molecular sieve

Technical field

The present invention relates to a kind of preparation method of Y type molecular sieve, particularly a kind of preparation side of small crystal grain Y-shaped molecular sieve Method.

Background technology

Y type molecular sieve be at present in residual oil cracking field can the most universal cracking active component, crystal grain is generally 1000nm or so, its crystal grain is larger, and duct is relatively long, and diffusional resistance is big, and macromolecular is difficult to enter is reacted inside duct, Product is also more difficult after reaction diffuses out, so the selectivity of its cracking activity and purpose product receives restriction.With conventional Y types Molecular sieve is compared, and small crystal grain Y-shaped molecular sieve has bigger external surface area and more outer surface activated centres, is conducive to improving big point Sub- hydrocarbon cracking capability, thus with more superior catalytic perfomance.Meanwhile, reducing Y type molecular sieve crystallite dimension can be with Improve inner surface active sites utilization rate.In general, diffusion of the reactant molecule in molecular sieve endoporus duct is referred to as transgranular expansion Dissipate.Molecular sieve inner surface is set all to be used for catalyzed conversion, it is necessary to micropore diffusion speed is more than endoporus catalyzed conversion Speed.It is the best way to shorten diffusion path.An effective way for overcoming micropore diffusion to limit is to reduce zeolite crystal Size.This can not only increase the external surface area of zeolite crystal, and shorten diffusion length simultaneously.EP0204236 is to small Crystal NaY molecular sieve and big crystal grain NaY molecular sieve are compared, and are as a result shown, the former has higher to RFCC Active and preferable selectivity.Therefore the technology of preparing of small crystal grain molecular sieve increasingly causes the attention of people.

At present, NaY molecular sieves are substantially using the directed agents proposed in US 3639099 and US 3671191 Method.This method is that to prepare mole composition be (15-17) Na first₂O∶Al₂O₃∶(14-16)SiO₂∶(285-357)H₂O guiding Agent, then the raw materials such as agent and waterglass, sodium metaaluminate, aluminum sulfate are directed to according to mol ratio (3-6) Na₂O∶Al₂O₃∶(8-12) SiO₂∶(120-200)H₂O ratio is mixed with gel, then by gel in 100 DEG C or so crystallization.The NaY of this method synthesis Framework of molecular sieve SiO₂/Al₂O₃Generally 5.0 or so, generally below 5.2, grain size is usually 500-800nm.

It is first by NaY Synthesis liquid 80 DEG C~180 that what is proposed in CN1081425A, which prepares the method for fine grain Y type molecular sieve, Pre- crystallization l~10 hour, are cooled to after room temperature and add directed agents at DEG C, and it is small then to continue crystallization 5~25 at 80 DEG C~100 DEG C When, the processing step is more complicated and is difficult to control to, and the hydrothermal stability of obtained fine grain Y type molecular sieve is poor.

Reduce the crystal grain of molecular sieve by adding organic solvent miscible with water into synthetic system, such as Using addition decentralized medium in USP3516786 and USP4372931, the sugared side of methanol, ethanol, dimethyl alum and left-right rotary Method, the grain size of its synthetic product is 10~100nm.The sial of molecular sieve synthesized by this method is relatively low, is only capable of synthesizing x types Molecular sieve, and organic solvent is readily volatilized under the conditions of hydrothermal crystallizing.

Using the method for improvement synthesis technique, such as heating of high-speed stirred, microwave in USP4587115 and USP4778666, its The grain size of synthetic product is about 500nm.This method building-up process is complicated, and synthesis cost is high, and the silicon of gained molecular sieve Aluminum ratio is low, and hydrothermal stability has much room for improvement.

CN1789125A proposes a kind of high silica alumina ratio, the preparation method of the NaY molecular sieve of little crystal grain, is to close conventional method Into gel at 50~100 DEG C after static 0~70h of crystallization, add silicon source, then continue at 90~120 DEG C crystallization 0.5~ 50h.This method mends silicon to improve silica alumina ratio after needing, step is complicated.

The preparation method for a kind of high silicon aluminium ratio small crystal NaY molecular sieve that CN1785807A is provided, in advance at 15~60 DEG C 0.5~48 hour obtained crystallization director of lower stirring ageing, is then directed to agent, water, silicon source, silicon source and reactant mixture is made, By reactant mixture crystallization, first step dynamic crystallization, second step static crystallization in two steps after stirring, eventually pass filter, wash Wash, dry, the high silicon aluminium ratio small crystal NaY molecular sieve that relative crystallinity is more than 80% is made.But hydrothermal stability is bad, HY points Son sieve is relatively low through crystallization reservations degree after 750 DEG C of hydro-thermal process 2 hours.

The preparation method of small crystal grain NaY molecular sieve disclosed in CN92105661.3, its preparation process is：It will be free of and lead first To the silica-alumina gel of agent in the input orientation agent again in 1 ~ 10 hour of 80 ~ 180 DEG C of crystallization, then continue crystallization 5 ~ 25 at 90 ~ 100 DEG C Hour, until crystallization is complete.Small crystal grain NaY molecular sieve made from this method is compared with NaY molecular sieve made from conventional method, is had Identical silica alumina ratio and crystallinity, simply smaller crystal grain is 0.1 ~ 0.5 micron.Therefore, the fine grain NaY molecule obtained by this method The silica alumina ratio of sieve is still relatively low, and generally less than 5, and also its crystallinity also awaits further raising.

CN101722023A discloses a kind of fine grain NaY type molecular sieve and preparation method thereof.The fine grain NaY type molecule The SiO of sieve₂/Al₂O₃Mol ratio is 4.0~6.0, and average grain diameter, in 100~700nm, is using low temperature synthesis directed agents, low temperature Prepared by the method that synthesized gel rubber and two sections of alternating temperature dynamic crystallizations are combined, this method is the method system using optimum synthesis condition Standby fine grain NaY type molecular sieve, its silica alumina ratio is still relatively low, and its heat endurance and hydrothermal stability await further carrying It is high.

At present, existing method fine grain NaY type molecular sieve is in preparation process, and silicon and aluminium are easy to run off, and silicon utilization rate is low, and And silicon, aluminium distributing inhomogeneity, easily reunite, therefore still can not to prepare silica alumina ratio high for existing method, and heat endurance and Hydrothermal stability and good fine grain NaY type molecular sieve.

Small crystal grain NaY molecular sieve is that do not possess acidity, it is necessary to processing is modified, to meet the performance of Cracking catalyst It is required that.CN1382632A discloses a kind of super stabilizing method of small-grain Y-type zeolite, and this method is the drying gas with silicon tetrachloride Body and fine grain NaY zeolitic contact, are obtained after washing, because the heat and hydrothermal stability of its raw material itself are just poor, simultaneously The inventive method is to handle molecular sieve by the way of gas phase dealumination complement silicon, and this make it that the heat and hydrothermal stability of product are worse, Activity is low.Fine grain NaY zeolite especially poor to heat endurance and hydrothermal stability, itself sial skeleton structure it is steady It is qualitative just it is poor, the removing of framework aluminum is easily caused in modifying process, at the same also some framework silicon also with removing, Easily cause part skeleton and the phenomenon caved in occur so that the crystallization reservation degree of product is relatively low, molecular sieve active and stably Property is not high.

CN200910165116.X discloses a kind of small crystal grain Y-shaped molecular sieve and preparation method thereof.Handled by this method Raw material small crystal grain NaY molecular sieve is prepared by the method disclosed in CN101722023A, i.e. SiO₂/Al₂O₃Mol ratio be 4.0~ 6.0, average grain diameter passes sequentially through successive modified i.e. ammonium exchange, at ammonium hexafluorosilicate dealumination complement silicon, hydro-thermal in 100~700nm The mixed aqueous solution processing of reason, aluminium salt and acid, obtains small-grain Y molecular sieve.In this method, need first to raw material ammonium hexafluorosilicate After dealumination complement silicon processing, then the processing such as hydro-thermal process is carried out, the skeleton structure that so could reduce molecular sieve is caved in, and raising divides The crystallization reservation degree of son sieve, but this method due to occurring the sial isomorphous due to first with after the processing of ammonium hexafluorosilicate dealumination complement silicon, taking In generation, molecular sieve silica constructed of aluminium is than more complete, then carries out hydro-thermal process, and the secondary pore of formation is few, and secondary pore proportion is low.

At present, because the hydrothermal stability of small crystal grain NaY molecular sieve is poor, structural instability, by successive modified, it is impossible to Structural integrity is obtained, crystallinity is high and has the small crystal grain Y-shaped molecular sieve of more secondary pore.

The content of the invention

In order to overcome weak point of the prior art, the invention provides a kind of high silica alumina ratio, high-crystallinity, secondary pore The preparation method of many, bigger serface small crystal grain Y-shaped molecular sieve.This method preparation flow is simple, prepares cost low.

The preparation method of the small crystal grain Y-shaped molecular sieve of the present invention, including：

（1）The preparation of fine grain NaY type molecular sieve；

（2）Fine grain NaY is used and contains alkaline solution treatment；

（3）By step（2）Obtained fine grain NaY type molecular sieve is prepared into Na₂O content≤2.5wt% little crystal grain NH₄NaY；

（4）Step（3）The molecular sieve of gained carries out dealumination complement silicon with hexafluorosilicic acid aqueous ammonium, obtained molecular sieve and pair Product is separated；

（5）To step（4）Obtain little crystal grain NH₄NaY molecular sieve carries out hydro-thermal process；

（6）By step（5）Obtained molecular sieve, which is used, contains NH₄ ⁺And H⁺Mixed solution processing, it is scrubbed and dry, obtain small Grain Y-molecular sieve.

In the inventive method in step (1) fine grain NaY type molecular sieve preparation method, including：

A, preparation directed agents：Silicon source, silicon source, alkali source and water are fed intake according to following proportioning：(6~30) Na₂O：Al₂O₃：(6 ~30) SiO₂：(100~460) H₂O, after stirring, stirs ageing at 0~20 DEG C by mixture and is made for 0.5~24 hour Directed agents；

B, amorphous silica-alumina predecessor prepared using acid-base precipitation method, using the weight of the butt of amorphous silica-alumina predecessor as Benchmark, the content that silicon is counted using silica is 40wt%~75wt%, preferably 55 wt%~70wt%；Its preparation process includes acid In alkali and plastic, aging, wherein silicon be introduced into the method for reaction system be in aluminiferous material and plastic before and/or plastic during Introducing portion contain silicon materials, remainder containing silicon materials be in aluminiferous material and plastic after and introduce before ageing；

C, prepare silica-alumina gel

By (0.5~6) Na₂O：Al₂O₃：(7~11) SiO₂：(100~460) H₂O total molar ratio, at 0~40 DEG C To step under conditions of quick stirring（2）Water, silicon source, directed agents and alkali source are added in the amorphous silica-alumina predecessor of gained, and Control ph is 9.5 ~ 12.0, and uniform stirring obtains silica-alumina gel；Wherein directed agents addition accounts for the 1% of silica-alumina gel weight ~20%,

Reactant mixture obtained by D, step C is washed through two step dynamic crystallizations, then through filtering, is dried, is obtained little crystal grain NaY molecular sieve.

In the present invention, in step A and C, silicon source, alkali source can be using the conventional silicon sources and alkali source for preparing molecular sieve, the present invention In preferably silicon source use sodium metasilicate, alkali source uses sodium hydroxide.In step A, silicon source can prepare the silicon source of molecular sieve using routine, It is preferred to use sodium metaaluminate in the present invention.

In the present invention, step B is preferably in aluminiferous material and after plastic and the silicon that introduces before ageing is in terms of silica The silicon accounted in amorphous silica-alumina predecessor 5wt% ~ 85wt% in terms of silica, preferably 30wt% ~ 70wt%.

In the present invention, the preparation method of step B amorphous silica-alumina predecessor is using conventional acid-base precipitation method, wherein wrapping Acid-base neutralization plastic is included, aging, wherein acid-base neutralization plastic process are usually the neutralization reaction of acid material and alkaline material Journey.Neutralizing plastic process can be by the way of acid material or the continuous acid-base titration of alkaline material, it would however also be possible to employ acid The mode that material and alkaline material cocurrent are neutralized.The method that wherein silicon is introduced into reaction system is as follows：In aluminiferous material and plastic During preceding and/or plastic introducing portion contain silicon materials, remainder containing silicon materials be in aluminiferous material and plastic after and Introduced before aging.Silicon can be according to the different property containing silicon materials in aluminiferous material and before plastic and/or during plastic Matter carries out neutralization plastic again after being mixed with acid material or alkaline material（When such as using sodium metasilicate containing silicon materials, metasilicic acid Sodium can be mixed with alkaline material；When using Ludox containing silicon materials, acid aluminiferous material is added）, can also will contain silicon materials Be individually added into aluminiferous material and during plastic in reaction system or the above method combination.Plastic material one As include aluminiferous material（Al₂(SO₄)₃、AlCl₃、Al(NO₃)₃And NaAlO₂One or more in）, containing silicon materials（Water glass One or more in glass, Ludox and organic silicon-containing compound etc., wherein organic silicon-containing compound is silanol, silicon ether and silica One or more in alkane, precipitating reagent is divided into acidic precipitation agent and alkaline precipitating agent, and wherein alkaline precipitating agent is sodium hydroxide, ammonia One or more in water, sodium carbonate, sodium acid carbonate, acidic precipitation agent is CO₂Or nitric acid, according to the different choice of plastic process Use, conventional mode of operation mainly has：（1）Acid aluminium salt（Al₂(SO₄)₃、AlCl₃、Al(NO₃)₃）With basic aluminium salt （NaAlO₂）Or alkaline precipitating agent（NaOH、NH₄OH）Neutralize plastic,（2）Basic aluminium salt（NaAlO₂）With acidic precipitation agent（CO₂） Neutralize plastic.Described plastic process is general to be carried out at room temperature ~ 85 DEG C, is relatively suitably for 40 ~ 80 DEG C, preferably 50 ~ 70 DEG C.Institute The pH value for the plastic process control system stated is 7.0 ~ 10.0, preferably 7.5 ~ 9.0.When using continuous acid-base titration, control The pH value of final plastic system is 7.0 ~ 10.0, preferably 7.5 ~ 9.0, when using in cocurrent and colloid system is made in plastic time control PH value remains 7.0 ~ 10.0, preferably 7.5 ~ 9.0.Aging is carried out after plastic, aging condition is as follows：PH is 7.0 ~ 10.0, excellent Elect 7.0 ~ 9.5 as, ageing time 0.2 ~ 8.0 hour is relatively adapted at 0.5 ~ 5 hour, preferably 1 ~ 3 hour, aging temperature was room Temperature ~ 85 DEG C, preferably 40 ~ 80 DEG C.Temperature and pH when temperature and pH during aging are with neutralizing is preferably identical.

In step C, 0~40 DEG C of controlling reaction temperature, preferably 10 ~ 30 DEG C, pH value 9.5~12.0, preferable ph 10~11.

Reactant mixture obtained by step D carries out crystallization and uses two step dynamic crystallizations, and the wherein first step carries out dynamic crystallization Condition it is as follows：Temperature control is at 50~90 DEG C, and crystallization time is 0.5~18 hour；Second step carries out the condition of dynamic crystallization It is as follows：Temperature control is at 80~140 DEG C, and crystallization time is 3~10 hours, after the completion of crystallization, then through filtering, washing, dry, system Obtain product.Two step dynamic crystallization conditions are preferably as follows：The first step：Temperature control is at 60~80 DEG C, and crystallization time is 1~10 small When；Second step：Temperature control is at 80~120 DEG C, and crystallization time is 5~10 hours.

Step（1）Described in small crystal grain NaY molecular sieve, its property is as follows：SiO₂/Al₂O₃Mol ratio is 5.0 ~ 9.0, excellent 6.0~9.0, more preferably 7.0~8.0 are selected, average grain diameter is 200~700nm, preferably 300~500nm；Compare table The m of face 800~1000²/ g, preferably 850~950 m²/ g, 0.30/~0.45mL/g of pore volume, relative crystallinity be 90%~ 130%, cell parameter be 2.460~2.470nm, through in 650 DEG C of air be calcined 3 hours after relative crystallinity be generally 85% with On, preferably 90%~110%, it is generally more than 85% through relative crystallinity after 700 DEG C of water vapour hydro-thermal process 2 hours, it is excellent Elect 90%~110% as.

Step（2）In, small crystal grain NaY molecular sieve is well mixed with the aqueous solution mashing of alkali, and maintain 60~120 DEG C 1~4h of stir process under temperature conditionss, filtering, washing.Alkali wherein used is NaOH, KOH or NaOH and KOH mixture. The concentration that the concentration of the aqueous solution of alkali is generally molecular sieve in 0.1~3 mol/L, slurries is 0.05~1.0g/mL.

Step（4）In, little crystal grain NH is added in aqueous medium₄NaY（Solid-liquid weight compares 1：4~1：8）, stir and be warming up to 90~120 DEG C, hexafluorosilicic acid aqueous ammonium is then added dropwise to, constant temperature is stirred 1~2 hour after completion of dropping, separates molecular sieve And accessory substance, and filter, dry.10 wt% of concentration ~ 40wt% of hexafluorosilicic acid aqueous ammonium, ammonium hexafluorosilicate addition is small Crystal grain NH₄10 wt% of NaY molecular sieve ~ 50wt%.

Step（5）In, the condition of described hydro-thermal process is as follows：Treatment temperature is controlled at 500~750 DEG C, is preferably controlled At 600~700 DEG C, pressure is 0.01~0.50MPa, and preferably 0.05~0.30MPa, processing time is 1.0~4.0 hours.

Step（6）In, by the molecular sieve after hydro-thermal process with acid and containing NH₄ ⁺Salt composition mixed solution contact, exchange Na in molecular sieve⁺With the part non-framework aluminum in removing molecular sieve, during acid therein can be hydrochloric acid, carbonic acid, nitric acid, sulfuric acid One or more, containing NH₄ ⁺Salt be one or more in the ammonium salt of the acid group containing the above；H in mixed solution⁺Concentration be 0.05~0.6mol/L, NH₄ ⁺Concentration be 0.5~3.0mol/L, exchange temperature be 70~120 DEG C, exchange slurries in molecular sieve Concentration be 0.1~0.5g/mL, swap time be 0.5~3.0 hour, exchange step may be repeated 1~4 time.Then remove Mother liquor, is washed with water, and dries.

Other operating procedures in the modified Y molecular sieve preparation method of the present invention, such as ammonium salt are exchanged can be normal using this area The operating method and condition of rule.Step（3）The method exchanged using ammonium salt, it is specific as follows：Using NaY molecular sieve as raw material, with can The aqueous solution of undissolved ammonium salt is exchanged 0.5~3.0 hour at 70~120 DEG C at preferably 80~100 DEG C, and Y molecular sieve is exchanging slurry Concentration in liquid is 0.05~0.50g/mL, and repeated exchanged l~5 time filter off mother liquor, washed, dry.Ammonium salt such as ammonium chloride, carbon One or more in sour ammonium, ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium oxalate, ammonium citrate etc., the concentration of ammonium salt solution is 0.5 ~5.0mol/L.

The small-grain Y molecular sieve of the present invention, property is as follows：SiO₂/ A1₂O₃Mol ratio is 30~120, average grain diameter For 200~700nm, preferably 300~500nm, relative crystallinity is more than 100%, preferably 100% ~ 120%, lattice constant 2.425~2.450nm, specific surface area is 850~1000m²/ g, pore volume is 0.40~0.60mL/g, 1.7~10nm secondary pore Shared pore volume is more than the 50% of total pore volume, more preferably preferably 50% ~ 70%, 55% ~ 65%, Na₂O content≤ 0.15wt%.

The preparation method that the present invention is provided has the following advantages that：Due to the silicon for the NaY type Molecular sieve raw materials that the present invention is handled Aluminum ratio is higher, and crystallinity is high, and stability is good, so in the crystal structure of follow-up modification process, not saboteur's sieve, and The stability of final molecular sieve is not influenceed.Molecular sieve of the present invention has carried out alkali process before ammonium exchange, with chemical dealuminization afterwards Be engaged with hydro-thermal process, that is, reached preferable dealumination depth, and preferably maintain molecular sieve structure, at the same generate by Substantial amounts of secondary pore so that modified molecular screen product has good performance.

The small-grain Y molecular sieve of the present invention is particularly suitable for use in the acidic components of medium oil type hydrocracking catalyst, height ratio Surface and flourishing secondary pore not only promote the performance of hydrogenation activity, and are conducive to the diffusion of reaction product, hold charcoal ability Also greatly enhance, secondary pore is more, then reduce the occurrence probability of excessive fragmentation and second pyrolysis, so as to have catalyst Good activity, middle distillates oil selectivity and excellent product property.

Embodiment

In order to which the present invention is better described, the present invention is further illustrated with reference to embodiment and comparative example.But this hair Bright scope is not limited solely to the scope of these embodiments.Analysis method of the present invention：Specific surface area, pore volume use low temperature liquid nitrogen physics Absorption method, relative crystallinity and cell parameter use x-ray diffraction method, and silica alumina ratio uses chemical method, and the crystal grain of molecular sieve is big Small to be determined by the way of SEM (SEM), sodium content uses plasma emission spectrometry.

Embodiment 1

The present embodiment is preparing raw material small crystal grain NaY molecular sieve

NY-1 preparation

（1）The preparation of directed agents：Take 8g sodium hydrate solids to be dissolved in 80g water, add the g (Al of sodium metaaluminate 2.5₂O₃ Content is 45wt%, Na₂O content is 41wt%), then add 40g waterglass (SiO₂Content is 28wt%, Na₂O content is 8 Wt%), in 18 DEG C of stirring 4 hours obtained directed agents of ageing after being well mixed.

（2）The preparation of amorphous silica-alumina predecessor

Solid sodium aluminate is configured to 0.3L concentration for 100g A1₂O₃ / L sodium aluminate working solutions（a）.By concentrated ammonia liquor plus Enter appropriate distilled water diluting into about 10wt% weak aqua ammonias（b）.Take containing SiO₂28wt% sodium silicate solution, then to be diluted to 0.5L dense Spend for 140g SiO₂/ L sodium metasilicate working solutions（c）.Take and 0.5 liter of distilled water is added in one 5 liters of steel retort, tank and is stirred Mix and be heated to after 70 DEG C, have respectively while opening（a）、（b）With（c）The valve of Sulfur capacity device, control（a）With（c）Flow with The neutralization reaction time is set to be adjusted at 40 minutes, and rapidly（b）Flow the pH value of system is maintained at 7~8, and control system Temperature is at 60 DEG C or so.After the completion of reacting aluminum sulfate, stop adding（b）,（c）Addition be 0.17L, the silicon-aluminum sol of generation Stablize after 20 minutes, continuously add（c）0.33L, is added in 10 minutes, starts the ageing process of system, keeps pH value 8.0, Temperature 60 C, aging 30 minutes.

（3）The preparation of gel

In step（2）1L H are added in resulting slurries₂O、140g SiO₂/ L sodium metasilicate working solution 0.6L and step （1）The directed agents 100g of preparation, the pH value of gel is 11.5, and 15 DEG C of controlling reaction temperature, uniform stirring 30 minutes staticizes 2.5 Hour.

（4）Crystallization

By step（2）Resulting gel is poured into stainless steel cauldron, is stirred crystallization 5 hours at 75 DEG C, is then heated up To 110 DEG C, then stirring crystallization 7 hours filters, washs, dry NaY molecular sieve product NY-1, and property is listed in table l.

NY-2 preparation

（1）The preparation of directed agents：Take 10 g sodium hydrate solids to be dissolved in 90g water, add the g (Al of sodium metaaluminate 3₂O₃ Content is 45wt%, Na₂O content is 41wt%), then add 50g waterglass (SiO₂Content is 28wt%, Na₂O content is 8wt%), in 20 DEG C of stirring 4 hours obtained directed agents of ageing after being well mixed.

（2）The preparation of amorphous silica-alumina predecessor

Solid aluminum sulfate is configured to 0.5L concentration for 80g A1₂O₃ / L aluminum sulfate working solutions（a）.Concentrated ammonia liquor is added Appropriate distilled water diluting is into about 10wt% weak aqua ammonias（b）.Take containing SiO₂28wt% sodium silicate solution, then it is diluted to 0.4L concentration For 150g SiO₂/ L sodium metasilicate working solutions（c）.Take and 0.5 liter of distilled water is added in one 5 liters of steel retort, tank and is stirred It is heated to after 70 DEG C, has respectively while opening（a）、（b）With（c）The valve of container, control（a）With（c）Flow so that in Adjusted with the reaction time at 40 minutes, and rapidly（b）Flow the pH value of system is maintained at 7~8, and the temperature of control system At 60 DEG C or so.After the completion of reacting aluminum sulfate, stop adding（b）,（c）Addition be 0.2L, the silicon-aluminum sol of generation is stable After 20 minutes, continuously add（c）0.2L, is added in 10 minutes, starts the ageing process of system, keeps pH value in 8.0, temperature 60 DEG C, aging 30 minutes.

（3）The preparation of gel

In step（2）1.2L H are added in resulting slurries₂O、150g SiO₂/ L sodium metasilicate working solution 0.8L and step Suddenly（1）The directed agents 120g of preparation, the pH value of gel is 12, and 30 DEG C of controlling reaction temperature, uniform stirring 30 minutes staticizes 3 small When.

（4）Crystallization

By step（2）Resulting gel is poured into stainless steel cauldron, is stirred crystallization 6 hours at 80 DEG C, is then heated up To 120 DEG C, then stirring crystallization 5 hours filters, washs, dry NaY molecular sieve product NY-2, and property is listed in table l.

Embodiment 2

Alkali process is carried out to raw material small crystal grain NaY molecular sieve first, is 1 mol/L's by 1000 grams of NY-1 and 5L concentration NaOH solution mashing is well mixed, and maintains stir process 2h under 80 DEG C of temperature conditionss, filters, is washed to solution in Property；Filter cake is in contact with 10 liters of 0.5mol/L aqueous ammonium nitrate solutions, speed of agitator is 300rpm, constant temperature is stirred at 90 DEG C L hours, then filtering molecular was sieved, and stays sample, analyzes Na₂O content；Aforesaid operations are repeated, until Na in molecular sieve₂O content 2.5wt% is reached, dried sample number into spectrum is obtained for NNY-1.

Embodiment 3

Alkali process is carried out to raw material small crystal grain NaY molecular sieve first, is 0.8 mol/L's by 1000 grams of NY-2 and 5L concentration KOH solution mashing is well mixed, and maintains stir process 2h under 80 DEG C of temperature conditionss, filters, is washed to solution close to neutrality； Filter cake is in contact with 10 liters of 0.5mol/L aqueous ammonium nitrate solutions, speed of agitator is 300rpm, constant temperature stirring l is small at 95 DEG C When, then filtering molecular is sieved, and stays sample, analyzes Na₂O content；Aforesaid operations are repeated, until Na in molecular sieve₂O content reaches To 2.5wt%, dried sample number into spectrum is obtained for NNY-2.

Embodiment 4

Take 100 grams of NNY-1 to be beaten with deionized water, and be brought rapidly up under conditions of stirring to 95 DEG C, then with uniform Speed be added dropwise within 2 hours by 25 grams of ammonium hexafluorosilicates and 150m1 deionized waters configuration the aqueous solution, add rear slurry and exist 2 hours of constant temperature under 95 DEG C of stirring conditions, 10 minutes are stood, dried after 3 washings and filtering, sample after drying is placed in In heat-treatment furnace, 500 DEG C/h heating rate is controlled, temperature is risen to 600 DEG C, while the water vapor pressure of the system of maintenance is 0.15MPa, is handled 2 hours, and sample is taken out in cooling；Filter cake is contained into NH with 500mL₄ ⁺And H⁺Concentration be respectively 0.6mol/L and Non-framework aluminum in 0.1mol/L mixed solution (ammonium chloride and hydrochloric acid) processing, removing sample, dealuminzation condition is at 80 DEG C Reason 2 hours, and wash filter cake with hot deionized water, stops close to after 7 washing with the pH value of cleaning solution, filter cake in an oven 120 DEG C dry 5 hours, obtain the small crystal grain Y-shaped molecular sieve product A of the present invention, product A physico-chemical property is shown in Table 2.

Embodiment 5

Take 100 grams of NNY-1 to be beaten with deionized water, and be brought rapidly up under conditions of stirring to 90 DEG C, then with uniform Speed be added dropwise within 2 hours by 30 grams of ammonium hexafluorosilicates and 150m1 deionized waters configuration the aqueous solution, add rear slurry and exist 2 hours of constant temperature under 90 DEG C of stirring conditions, 10 minutes are stood, dried after 3 washings and filtering, sample after drying is placed in In heat-treatment furnace, temperature is risen to 650 DEG C by the heating rate of 400 DEG C/h of control, while the steam partial pressure of the system of maintenance 0.08MPa, is handled 2 hours, and sample is taken out in cooling；Filter cake is contained into NH with 400mL₄ ⁺And H⁺Concentration be respectively 0.8mol/L and Non-framework aluminum in 0.2mol/L mixed solution (ammonium nitrate and nitric acid) processing, removing sample, dealuminzation condition is at 70 DEG C Processing 3 hours, filtering, and filter cake is washed with hot deionized water, stopping washing, filter cake close to after 7 with the pH value of cleaning solution is drying 120 DEG C of dryings 5 hours in case, obtain the small crystal grain Y-shaped molecular sieve product B of the present invention, and product B physico-chemical property is shown in Table 2.

Embodiment 6

Take 100 grams of NNY-2 to be beaten with deionized water, and be brought rapidly up under conditions of stirring to 100 DEG C, then with uniform Speed be added dropwise within 2 hours by 20 grams of ammonium hexafluorosilicates and 150m1 deionized waters configuration the aqueous solution, add rear slurry and exist 2 hours of constant temperature under 100 DEG C of stirring conditions, 10 minutes are stood, dried after 3 washings and filtering, sample after drying is put In hydro-thermal process stove, temperature is risen to 700 DEG C by the heating rate of 400 DEG C/h of control, while the water vapour of the system of maintenance Partial pressure 0.1MPa, is handled 2 hours, and sample is taken out in cooling；Filter cake is contained into NH with 400mL₄ ⁺And H⁺Concentration be respectively 1.0mol/L Handled with 0.2mol/L mixed solution (ammonium chloride and hydrochloric acid), the non-framework aluminum in removing sample, dealuminzation condition is at 75 DEG C Lower processing is filtered for 3 hours, and washs filter cake with hot deionized water, and stopping washing, filter cake close to after 7 with the pH value of cleaning solution is drying 120 DEG C of dryings 6 hours in case, obtain the small crystal grain Y-shaped molecular sieve products C of the present invention, and the physico-chemical property of products C is shown in Table 2.

Comparative example 1

1st, fine grain NaY is prepared with reference to CN101722023A

Feedstock property used is as follows in this comparative example：Low alkali sodium metaaluminate：Na₂O content 120g/L, Al₂O₃Content 40g/L；Waterglass：SiO₂Content 250g/L；Aluminum sulfate：Al₂O₃Content 90g/L.

(1) preparation of directed agents：NY-1 in the preparation be the same as Example 1 of directed agents.

(2) preparation of gel：Temperature is 8 DEG C, under stirring condition, and 59.4mL sulphur is sequentially added into 208mL waterglass Sour aluminium, 62.7mL low sodium metaaluminate and 42.2mL directed agents, then constant temperature constant speed stirring 1.5 hours, then by obtained conjunction Into liquid static aging 8 hours at the temperature disclosed above, gel is obtained.

(3) crystallization：Under agitation, the gel in synthesis reactor is raised to 50 DEG C, constant temperature stirring crystallization 7 in 20 minutes Hour；After low temperature crystallized end, the temperature in synthesis reactor is brought up to 120 DEG C in 20 minutes, then constant temperature is stirred 6 hours. Through being filtered, washed and dried drying, product little crystal grain CNY-l is obtained, product property is shown in Table 1.

2nd, ammonium exchange is carried out to raw material small crystal grain NaY molecular sieve CNY-1, treatment conditions be the same as Example 2 obtains dried Sample number into spectrum is CNNY-1.

3rd, subsequent treatment, processing mode and condition be the same as Example 4 are carried out to CNNY-1, obtains Reference Product CA.CA thing Change property and be shown in Table 2.

Comparative example 2

1st, fine grain NaY is prepared with reference to CN1785807A

The preparation of directed agents：NY-1 in the preparation be the same as Example 1 of directed agents.

14.21g water is positioned in beaker, it is 60 DEG C to control fluid temperature in beaker, quick stirring is lower to be added simultaneously 12.79g50wt% A1₂(SO₄)₃) solution and 31.91g waterglass.After stirring, above-mentioned directed agents 1.90g, gel are added PH value be 12.5, after stirring, be loaded into stainless steel cauldron, stir crystallization 6 hours at 60 DEG C, then heat to 100 DEG C of static crystallizations 60 hours, then filter, wash, dry CNY-2 zeolite products, and product property is shown in Table 1.

2nd, ammonium exchange is carried out to raw material small crystal grain NaY molecular sieve CNY-1, treatment conditions be the same as Example 2 obtains dried Sample number into spectrum is CNNY-2.

3rd, subsequent treatment, processing mode and condition be the same as Example 4 are carried out to CNNY-2, obtains Reference Product CB.CB thing Change property and be shown in Table 2.

Comparative example 3

1st, fine grain NaY is prepared with reference to CN92105661.3

Feedstock property in this comparative example used in NaY is as follows：Low alkali sodium metaaluminate：Na₂O content 120g/L, Al₂O₃Content 40g/L；Waterglass：SiO₂Content 250g/L；Aluminum sulfate：Al₂O₃Content 90g/L.

(1) preparation of directed agents：NY-1 in the preparation be the same as Example 1 of directed agents.

(2) preparation of gel：60mL aluminum sulfate, 60mL low sodium metaaluminate are sequentially added in 220mL waterglass, Then constant temperature constant speed is stirred 0.5 hour, and silica-alumina gel is made.

(3) crystallization：Under agitation, the gel in synthesis reactor is raised to 140 DEG C, constant temperature stirring crystallization in 30 minutes 2 hours；35mL directed agents are added, are mixed evenly, then continue crystallization 15 hours at 100 DEG C, through filtering, are washed and dry It is dry, products C NY-3 is obtained, product property is shown in Table 1.

2nd, ammonium exchange is carried out to raw material small crystal grain NaY molecular sieve CNY-3, treatment conditions be the same as Example 2 obtains dried Sample number into spectrum is CNNY-3.

3rd, subsequent treatment, processing mode and condition be the same as Example 4 are carried out to CNNY-3, obtains Reference Product CC.CC thing Change property and be shown in Table 2.

Comparative example 4

1st, prepared by fine grain NaY

（1）The preparation of directed agents：NY-1 in the preparation be the same as Example 1 of directed agents.

（2）The preparation of amorphous silica-alumina predecessor.

Solid sodium aluminate is configured to 0.3L concentration for 100g A1₂O₃ / L sodium aluminate working solutions（a）.By concentrated ammonia liquor plus Enter appropriate distilled water diluting into about 10wt% weak aqua ammonias（b）.Take containing SiO₂28wt% sodium silicate solution, then to be diluted to 0.5L dense Spend for 140g SiO₂/ L sodium metasilicate working solutions（c）.Take and 0.5 liter of distilled water is added in one 5 liters of steel retort, tank and is stirred Mix and be heated to after 70 DEG C, have respectively while opening（a）、（b）With（c）The valve of container, control（a）Flow so as to neutralize anti- Adjusted between seasonable at 40 minutes, and rapidly（b）Flow the pH value of system is maintained at 7~8, and control system temperature 60 DEG C or so.After the completion of reacting aluminum sulfate, stop adding（b）, the silicon-aluminum sol of generation stablizes 40 minutes.

（3）The preparation be the same as Example 1 of gel.

（4）Crystallization be the same as Example 1, obtains products C NY-4, and product property is shown in Table 1.

2nd, ammonium exchange is carried out to raw material small crystal grain NaY molecular sieve CNY-4, treatment conditions be the same as Example 2 obtains dried Sample number into spectrum is CNNY-4.

3rd, subsequent treatment, processing mode and condition be the same as Example 4 are carried out to CNNY-4, obtains Reference Product CD.CD thing Change property and be shown in Table 2.

Comparative example 5

CNNY-5 preparation is with comparative example 1.Then it is modified using CN200910165116.X method, it is specific as follows：Take 100 grams of CNNY-5 are beaten with 100mL deionized waters, and are brought rapidly up under conditions of stirring to 95 DEG C, then with uniform speed The aqueous solution by 25 grams of ammonium hexafluorosilicates and the configuration of 150m1 deionized waters is added dropwise in degree within 2 hours, adds rear slurry at 95 DEG C 2 hours of constant temperature under stirring condition, 10 minutes are stood, by 3 washings, filtering, dried；Sample after above-mentioned drying is placed in heat In treatment furnace, 500 DEG C/h heating rate is controlled, temperature is risen to 600 DEG C, while the water vapor pressure of the system of maintenance is 0.15MPa, is handled 2 hours, and sample is taken out in cooling；Final sample contains Al with 400mL³⁺And H⁺Concentration be respectively 1.0mol/L With the non-framework aluminum in 0.5mol/L mixed solution (aluminum nitrate and nitric acid) removing sample, dealuminzation condition is to handle 2 at 80 DEG C Hour, and filter cake is washed with hot deionized water, stop washing, filter cake close to after 7 with the pH value of cleaning solution does for 120 DEG C in an oven Dry 5 hours, obtain Reference Product CE.CE physico-chemical property is shown in Table 2.

Comparative example 6

100gNNY-1 is taken, the NNY-1 of the present invention is modified using CN200910165116.X method, specific preparation side Method obtains Reference Product CF with comparative example 5.CF physico-chemical property is shown in Table 2.

The property of the small crystal grain NaY molecular sieve of table 1

In table 1, * roasting conditions：It is calcined 3 hours in 650 DEG C of air；The condition of * hydro-thermal process：700 DEG C of steam treatments 2 hours.

The property of the finished product small crystal grain Y-shaped molecular sieve of table 2

Claims (18)

1. a kind of preparation method of small crystal grain Y-shaped molecular sieve, including：

（1）The preparation of fine grain NaY type molecular sieve；

（2）Fine grain NaY is used and contains alkaline solution treatment；

（3）By step（2）Obtained fine grain NaY type molecular sieve is prepared into Na₂O content≤2.5wt% little crystal grain NH₄NaY；

（4）Step（3）The molecular sieve of gained carries out dealumination complement silicon with hexafluorosilicic acid aqueous ammonium, obtained molecular sieve and accessory substance Separation；

（5）To step（4）Obtain little crystal grain NH₄NaY molecular sieve carries out hydro-thermal process；

（6）By step（5）Obtained molecular sieve, which is used, contains NH₄ ⁺And H⁺Mixed solution processing, it is scrubbed and dry, obtain little crystal grain Y type molecular sieve；

The preparation method of fine grain NaY type molecular sieve wherein in step (1), including：

A, preparation directed agents：Silicon source, silicon source, alkali source and water are fed intake according to following proportioning：(6~30) Na₂O：Al₂O₃：(6~ 30)SiO₂：(100~460) H₂O, after stirring, mixture is stirred to be aged to be made for 0.5~24 hour at 0~20 DEG C and led To agent；

B, amorphous silica-alumina predecessor prepared using acid-base precipitation method, using the weight of the butt of amorphous silica-alumina predecessor as base Standard, the content that silicon is counted using silica is 40wt%~75wt%；Its preparation process includes acid-base neutralization plastic, wherein aging, silicon Be introduced into the method for reaction system be in aluminiferous material and plastic before and/or plastic during introducing portion contain silicon materials, it is remaining Part containing silicon materials be in aluminiferous material and plastic after and introduce before ageing；

C, prepare silica-alumina gel：By (0.5~6) Na₂O：Al₂O₃：(7~11) SiO₂：(100~460) H₂O's always feeds intake mole Than adding water, silicon source, directed agents into the amorphous silica-alumina predecessor obtained by step B under conditions of 0~40 DEG C of quick stirring And alkali source, and control ph is 9.5 ~ 12.0, uniform stirring obtains silica-alumina gel；Wherein directed agents addition accounts for silica-alumina gel The 1%~20% of weight,

Reactant mixture obtained by D, step C is washed through two step dynamic crystallizations, then through filtering, is dried, and obtains fine grain NaY point Son sieve.

2. in accordance with the method for claim 1, it is characterised in that in step B, amorphous silica-alumina predecessor, with amorphous silica-alumina On the basis of the weight of the butt of predecessor, the content that silicon is counted using silica is 55 wt%~70wt%.

3. in accordance with the method for claim 1, it is characterised in that in step B, in the preparation process of amorphous silica-alumina predecessor, In aluminiferous material and after plastic and silicon that the silicon that is introduced into before ageing is accounted in terms of silica in amorphous silica-alumina predecessor with 5wt% ~ 85wt% of silica meter.

4. in accordance with the method for claim 1, it is characterised in that in step B, the preparation process of amorphous silica-alumina predecessor In, the silicon that the silicon being introduced into aluminiferous material and after plastic and before ageing is accounted in terms of silica in amorphous silica-alumina predecessor 30wt% ~ 70wt% in terms of silica.

5. in accordance with the method for claim 1, it is characterised in that in step A and C, silicon source, alkali source are respectively sodium metasilicate and hydrogen Sodium oxide molybdena；In step A, silicon source is selected from sodium metaaluminate.

6. in accordance with the method for claim 1, it is characterised in that in step B, aluminiferous material is Al₂(SO₄)₃、AlCl₃、Al (NO₃)₃And NaAlO₂In one or more, containing silicon materials be waterglass, Ludox and organic silicon-containing compound in one kind or It is several, wherein organic silicon-containing compound be silanol, silicon ether and siloxanes in one or more, precipitating reagent be acidic precipitation agent or Alkaline precipitating agent, wherein alkaline precipitating agent are the one or more in sodium hydroxide, ammoniacal liquor, sodium carbonate, sodium acid carbonate, and acidity is heavy Shallow lake agent carbon dioxide or nitric acid.

7. in accordance with the method for claim 1, it is characterised in that in the acid-base precipitation method that step B is used, acid-base neutralization plastic Process is the neutralization reaction process of acid material and alkaline material, neutralizes plastic process continuous using acid material or alkaline material The mode of acid-base titration, or by the way of acid material and alkaline material cocurrent are neutralized.

8. in accordance with the method for claim 7, it is characterised in that in step B, containing silicon materials in aluminiferous material and before plastic And/or introduced during plastic, it is to enter again after being mixed according to the different properties containing silicon materials with acid material or alkaline material Row neutralizes plastic, or will contain silicon materials in aluminiferous material and be individually added into during plastic in reaction system, or on State the combination of method.

9. in accordance with the method for claim 1, it is characterised in that in step B, described plastic process is entered at room temperature ~ 85 DEG C OK, the pH value of control system is 7.0 ~ 10.0；Aging is carried out after plastic, aging condition is as follows：Aging pH is 7.0 ~ 10.0, aging 0.2 ~ 8.0 hour time, aging temperature is room temperature ~ 85 DEG C.

10. in accordance with the method for claim 1, it is characterised in that in step C, 10 ~ 30 DEG C of controlling reaction temperature, pH value 10~ 11。

11. in accordance with the method for claim 1, it is characterised in that step D uses two step dynamic crystallizations, the wherein first step is carried out The condition of dynamic crystallization is as follows：Temperature control is at 50~90 DEG C, and crystallization time is 0.5~18 hour；It is brilliant that second step enters Mobile state The condition of change is as follows：Temperature control is at 80~140 DEG C, and crystallization time is 3~10 hours.

12. in accordance with the method for claim 1, it is characterised in that step D uses two step dynamic crystallizations, the wherein first step is carried out The condition of dynamic crystallization is as follows：Temperature control is at 60~80 DEG C, and crystallization time is 1~10 hour；Second step carries out dynamic crystallization Condition it is as follows：Temperature control is at 80~120 DEG C, and crystallization time is 5~10 hours.

13. in accordance with the method for claim 1, it is characterised in that step（2）In, by small crystal grain NaY molecular sieve and the water of alkali Solution mashing is well mixed, and maintains 1~4h of stir process under 60~120 DEG C of temperature conditionss；Alkali wherein used be NaOH, KOH or NaOH and KOH mixture；The concentration of the aqueous solution of alkali is that the concentration of molecular sieve in 0.1~3 mol/L, slurries is 0.05~1.0g/mL.

14. in accordance with the method for claim 1, it is characterised in that step（4）In, compare 1 by solid-liquid weight in aqueous medium：4 ~1：8 add little crystal grain NH₄NaY molecular sieve, stirs and is warming up to 90~120 DEG C, be then added dropwise to hexafluorosilicic acid aqueous ammonium, Constant temperature is stirred 1~2 hour after completion of dropping, separation molecular sieve and accessory substance, and is filtered, dried；Hexafluorosilicic acid aqueous ammonium 10 wt% of concentration ~ 40wt%, ammonium hexafluorosilicate addition be little crystal grain NH₄10 wt% of NaY molecular sieve ~ 50wt%.

15. in accordance with the method for claim 1, it is characterised in that step（5）In, the condition of described hydro-thermal process is as follows： Treatment temperature control is at 500~750 DEG C, and pressure is 0.01~0.50MPa, and processing time is 1.0~4.0 hours.

16. in accordance with the method for claim 1, it is characterised in that step（5）In, the condition of described hydro-thermal process is as follows： Treatment temperature control is at 600~700 DEG C, and pressure is 0.05~0.30MPa, and processing time is 1.0~4.0 hours.

17. in accordance with the method for claim 1, it is characterised in that step（6）In, by the molecular sieve after hydro-thermal process with acid and Containing NH₄ ⁺Salt composition mixed solution contact, acid therein is the one or more in hydrochloric acid, carbonic acid, nitric acid, sulfuric acid, containing NH₄ ⁺Salt be one or more in the ammonium salt of the acid group containing the above；H in mixed solution⁺Concentration be 0.05~0.6mol/L, NH₄ ⁺ Concentration be 0.5~3.0mol/L, exchange temperature be 70~120 DEG C, exchange slurries in molecular sieve concentration be 0.1~0.5g/ ML, swap time is 0.5~3.0 hour, and exchange step repeats 1~4 time.

18. in accordance with the method for claim 1, it is characterised in that：Step（3）The method exchanged using ammonium salt, process is as follows： Using NaY molecular sieve as raw material, exchanged 0.5~3.0 hour at 70~120 DEG C with the aqueous solution of soluble ammonium salt, molecular sieve exists It is 0.05~0.50g/mL to exchange the concentration in slurries, and repeated exchanged l~5 time filter off mother liquor, washed, dry；Ammonium salt is chlorination One or more in ammonium, ammonium carbonate, ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium oxalate, ammonium citrate, the concentration of ammonium salt solution is 0.5~5.0mol/L.