Title of Invention

A PROCESS FOR THE PREPARATION OF CATALYST PARTICLES

Abstract

The present invention relates to a process for the preparation of catalyst particles with a particle diameter in the range 20-2000 microns involving the steps of agitating a: !eas; two dry catalyst ingredients, spraying a liquid binding agent on the catalyst ingredients while continuing the agitation, and isolating formed catalvst carticies with the desired particle diameter and eomnrisma the catalvst ingredients. In crntras: to the conventional way of preparing such panicles, spray-drying, the present process allows the formation of small particles from slurries with a high solids con rent. Hence, smaller amounts of liquid have to be

Full Text

PROCESS FOR THE PREPARATION OF CATALYST MICROSPHERES The present invention relates zc a process fcr the preparation cf catalyst compositions with a particle diameter in the range 2G-2QC0 microns. Within the specification. :he term cataiys: compositions also encompasses catalyst additives and adsorbents. -For several catalytic applications, such as fiuidized bed processes, small catalyst panicles are required. Such particles are generally practiced by spray-drying a mixture of the catalyst ingredients. For instance, fluid catalytic cracking (FCC) catalysts are generally prepared by spray-drying an acueous slum/ of zeolite, clay, and silica and/or alumina. Spray-drying involves pumping a slurry containing the catalyst ingredients through a nozzle (a high-pressure nozzle or a rotating wheel with nozzle) into a chamber heated with hot air. During this process, high shear is placed on the slurry, thereby creating small droplets that quickly dry in the heated chamber. Depending on the type cf nozzle used, the particle size distribution of the resulting catalyst particles depends on either the nozzle pressure or the rotating speed of the wheel, but generally lies in the range of 30-90 microns. Unfortunately, only slurries with a low solids content (i.e. below about 45 wt% solids) and, consequently, a high liquid content can be spray-dried. Slurries with a higher solids content either are too viscous to be pumped through the nozzle or will not give suitable droplets upon spraying. Due to this low solids limitation, large volumes of liquid are required, which have to be evaporated during the drying step. This is energy inefficient. This problem is solved by the process according to the present invention, which involves the following steps: a) agitating at least two dp/ catalyst ingredients, b) spraying a liquid binding agent on the catalyst ingredients while continuing the agitation, c) isolating formed catalyst particles with the desired particle diameter and comprising the catalyst ingredients, and d) optionally calcining the isolated catalyst particles. This process requires less liquid than spray-drying. Hence, less liquid has to ce evaporated in the drying step, making this process more energy efficient than spray-drying. The process according to the invention requires at least two individual catalyst ingredients to form a catalyst particle, it is not a process that involves only surface coating of existing catalyst particles as irv US 5.286,370 and US 5,001,096. Suitable agitation techniques involve fluidization and high-shear mixing. Fluidization is performed by fluidizing the catalyst ingredients in a stream of gas, generally air. A nozzle is present above the so formed fluidized bed. Through this nozzle, the liquid binding agent is sprayed on the catalyst ingredients. A suitable apparatus for performing this process is a fluidized bed granulator. The gas velocity influences the size of the catalyst particles obtained. This gas velocity preferably ranges from 1-10 times the minimum fluidization velocity and most preferably from 1-5 times the minimum fluidization velocity, with the minimum fluidization velocity being defined as the minimum gas velocity required for holding up the catalyst ingredients. It will be clear that this minimum velocity depends on the particle size of the .catalyst ingredients: the larger the particles, the higher the required minimum gas velocity. Catalyst ingredients for the preparation of FCC catalyst particles generally have a particle size up to about 10 microns. The temperature of the gas preferably ranges from 20° to 7CC3C, mere preferably from 50a to 200°C, and most preferably :":-- 30° - AZ~~-~ High-shear nixing is performed in a high-shear mixer. A nozzle is present in the mixer, above the catalyst ingredients. Through this nozzle, the iicuid bindinc agent is sprayed on the catalyst ingredients. The preferred shear rare ranges from 250 to 5000 s"1, mere preferably from 250 to 2500 s"\ and most preferably from 500 to -1000 s"1. The temperature during high shear mixing preferably is belcv/ 1CC3C, mere preferably below 50°C. and most preferably ambient. Catalyst ingredients which can be used in the crccess acccrdinc to the invention include soiid acids, alumina, iron (hydr)oxide, (meta)kaolin, bentcnite. (calcined) anionic clays, saponite, sepiolite, smectite, montmoriilonite, and mixtures thereof. Suitable sclid acids include zeolites such as zeolite beta, MCM-22. MCM-36, mordenite, faujasite zeolites such as X-zeolites and Y-zeoiites 'including H-Y-zeolites, RE-Y zeolites, and USY-zeolites), pentasil-type zeolites such as ZSM-5, non-zeoiitic solid acids such as silica-alumina, sulphated oxides such as sulphated oxides of zirconium, titanium, or tin, sulphated mixed oxides of zirconium, molybdenum, tungsten, etc., and chlorinated aluminium oxides. Suitable aluminas include boehmite, pseudoboehmite, transition aluminas such as alpha-, delta-, gamma-, eta-, theta-, and chi-alumina, aluminium trihydrate such as gibbsite or bauxite ore concentrate (BOC), and flash-calcined aluminium trihydrate. Examples of suitable anionic clays (also called hydrotalcite-like materials or layered double hydroxides) are Mg-Al anionic clays, Fe-AI anionic clays, Zn-AI anionic clays, Fe-Fe anionic clays, etc. The catalyst ingredients used have to be dry before starling the process according to the invention. The term "dry" in'thls context means that not more than 90% of the pore volume of these ingredients is filled v/ith water. Most of the aluminas used for FCC applications are made via precipitation processes. These processes usually involve the sequential steps of precipitation, crystallization, and dewatering. A suitable dewatering technique to obtain alumina sufficiently dry to be used In the process according to the invention uses a high-pressure filter. Zeolites are usually prepared via crystallization, wsshing/cewaterir.g, Ion-exchange with NH4 and rare earth rr.etais (RE), drying, caicinaticn, and milling. Suitable liquid binding agents include water, acidic aqueous solutions, or aqueous silicon and/or aluminium-containing solutions or suspensions. The term "liquid binding agent' refers to liquids, solutions, or suspensions that assist in bincing of the catalyst ingredients to form the cataiyst particles. The liquid binding agent can initiate this binding either during step b) or later, for instance during an additional calcination step. Whether or not binding takes place during step b) depends on the liquid binding agent and the cataiyst ingredients used. The desired liquid binding agent depends en the desired binder. For example: If anionic clay is the desired binder, water can be used as the liquid binding agent and a calcined anionic clay as one of the cataiyst ingredients. Said water will rehydrate the calcined anionic clay to form a binder anionic clay. If alumina is the desired binder, acidified water can be used as liquid binding agent and a peptizable alumina such as pseudoboehmite as one of the catalyst ingredients. Alternatively, aluminium chlcrohydrol (ACH) or aluminium nitrohydrol (ANH)-containing suspensions can be used as liquid binding agent, with formation of alumina binder, irrespective of the types of catalyst ingredients used. Consequently, if one of the catalyst ingredients is an alumina and ACH or ANH is used as liquid binding agent, the resulting catalyst will comprise two types of alumina. Another option to obtain a catalyst particle with an alumina binder is to use water as the liquid binding agent and flash-calcined aluminium . trihydrate as one of the catalyst ingredients. Although the iatter combination does not result in binding of the particles during step b), binding does take place during an additional calcination step (step d). If silica is the desired binder, a solution or suspension containing a silicon compound can be used' as liquid binding agent, irrespective of the types of Catalyst ingrecients used, examples cf suitace silicon compounds are silica sol, sodium (mets; silicate, and precipitated siiica. More tnan cne liquid binding agent can be _sed, which can be sprayed en the catalyst ingrecients sequentially. For instance, a siiiccn-ccntaining solution or • sol, or an aluminium chlcrchydrcl or nitrchy-rcl-containing sol can be used as a first liquid binding agent, while acidified wa:sr can be used as a second liquid binding agent Depending en the extern cf dryness cf :he catalyst ingredients, it may be preferred to spray some water on the catalyst ingredients before spraying the liquid binding agent. The required amount cf water is such that about 30% of the pores of the catalyst ingredients can.be filled with water. The liquid binding agent is preferably sprayed on the catalyst ingredients at a rate cf 1-1.5 times the required amount divided by the residence time. This residence time generally ranges from about 1 to 30 minutes. The droplet size preferably is between 1 and 20 urn. Agitation is continued until the right particie size is obtained. In the case of fluidized bed granulation, the gas velocity is selected in such a way that it can only hold up particles smaller than the desired size. Hence, once the particles have the desired size, they fall down. The particles obtained by the process according to the invention range in size from about 20 to about 2000 microns, preferably 20-600 microns, more preferably 20-200 microns, and most preferably 30-100 microns. .For fluid catalytic cracking (FCC) applications a particle size between 30 and 100 microns is preferred. If desired, the resulting carticies are dried ard/cr calcined. !f the applied iiauid oir.cir.g agent does net result in binding during agitation siec b). a calcinaiicn 3I5C 2) may be required to initiate this binding. Drying involves heating of the formed particles a: a tempera-re oreferabiy in the range 100-200aC. Calcination is preferably conducted st 3C0°--:2003C, mere preferably 3003-800°C: and mest preferably 30C:-5C03C for 15 minutes tc 2d hcurs, preferably 1-12 hcurs. and most creferablv 2-6 hcurs. The particles obtained by the process according tc the invention can be used for various purposes, e.g. as a catalyst, adsorbent, etc. Suitable catalytic applications include Gas to Liquid processes (e.g. Fischer-Tropsch), E-bed and H-cil processes, reforming, isomerization, slkylation, and auto exhaust catalysis. EXAMPLES Example 1 This Example describes the preparation of FCC catalyst particles with the following composition (on dry base): 15 wt% alumina, 20 wt% USY, 4 wt% silica, 61 wt% kaolin. A fluidized bed granulator was filled with about 200 g of a mixture of dry pseudoboehmite, dry kaolin, and dry zeolite. The mixture was fluidized and afterwards 35 g of silicasol were sprayed on top of the fluidized bed at a rate of 4.8 g/min. Simultaneously, the inlet temperature of the gas was set to 70°C. Next, 10% nitric acid solution was sprayed on top of the fluidized bed through the same nozzle at a rate of 4.8 g/min. After addition of 100 g of the nitric acid solution, liquid addition was stopped and the gas inlet temperature was set to 135°C to dry the material. The resulting FCC particles had a mean diameter (d50) of 75 microns. SEM analysis showed that the particles had a uniform distribution of ingredients. Example 2 This Example describes the preparation of FCC catalyst panicles with the following composition (en cry base): 15 wt% pseudoboehmite, 2C wt% USY, 10 wt% alumina originating from aluminium chlorohydrol (ACH), 55 wt% kaolin. A fluidized bed granulator was filled with about 200 g of a mixture of dry pseudoboehmite, dp/ kaolin, and dry zeoiite. The mixture was fluidized and afterwards 90 g of an aiuminium chlorchydcl suspension were sprayed on top of the fluidized bed at a rate of 4.8 g/min. Simultaneously, the inlet temperature of the gas was set to 70°C. Next, a 10% nitric acid solution was sprayed on top of the fluidized bed through the same nozzle at a rate of 4.8 g/min. After addition of 100 g of the nitric acid solution, the liquid addition was stopped and the gas inlet temperature was set to 135°C to dry the material. The resulting FCC particles had a mean diameter (d50) of 78 microns. SEM analysis showed that the particles had a uniform distribution of ingredients. Example 3 This Example describes the preparation of FCC catalyst particles with the following composition (on dry base): 25 wt% pseudoboehmite, 25 wt% USY, 35 wt% kaolin, and 15 wt% Mg-AI anionic clay. A Mg-AI anionic clay was first calcined and then rehydrated in aquesous suspension at hydrothermal conditions, i.e. 130°C and autogeneous pressure. A fluidized bed granulator was filled with about 200 g of a mixture of dry pseudoboehmite, kaolin, the anionic clay, and zeolite. The mixture was fluidized and afterwards 10% nitric acid solution was sprayed on top of the fluidized bed through the same nozzle at a rate of 4.8 g/min. Simultaneously, the inlet temperature of the gas was set to 70°C. After addition of 100 g of the nitric acid solution, liquid addition was stopped and the gas inlet temperature was set to 135°C to dry the material. The resulting FCC particles have a mean diameter (d50) of 75 microns. SEM analysis showed that the particles had a uniform distribution of ingredients. CLAIMS 1. Process for the preparation of catalyst particles with a panicle diameter in the range 20-2000 microns, which prccsss comprises the steps of: a) agitating at least two dry catalyst ingredients, b) spraying a liquid binding agent en the cataiys; Ingredients while continuing the agitation, c) isolating formed catalyst particles with the desired particle diameter and comprising the catalyst ingredients, and d) optionally calcining.the isolated catalyst particles. 2. Process according to claim 1 wherein agitation is performed by high-shear mixing. 3. Process according to claim 1 wherein agitation is performed by fluidization. 4. Process according to any one of the preceding claims wherein at least one of the catalyst ingredients is alumina, clay, or zeolite. 5. Process according to claim 4 wherein the catalyst particles are FCC catalyst particles or FCC catalyst additive particles. 6. Process according to any one of the preceding claims v/herein the liquid binding agent is selected from the group consisting of water, an aqueous acidic solution, a silicon-containing solution or suspension, a suspension comprising aluminium chlorohydrol and/or aluminium nitrohydrol, and mixtures thereof. 7. Process according to claim 2 wherein the shear rate applied en the catalyst

Documents:

1273-chenp-2005-abstract.pdf

1273-chenp-2005-claims.pdf

1273-chenp-2005-correspondnece-others.pdf

1273-chenp-2005-correspondnece-po.pdf

1273-chenp-2005-description(complete).pdf

1273-chenp-2005-form 1.pdf

1273-chenp-2005-form 3.pdf

1273-chenp-2005-form 5.pdf

1273-chenp-2005-form18.pdf

1273-chenp-2005-pct.pdf