Catalyst for enhancing liquid yield in thermal coking process

Abstract

The present invention provides a catalyst product comprising of (a) porous acidic clay material and (b) binder and matrix to shape the catalyst to either microspheres, pellet, tablet, extrudate and ring and suitable for enhancing the crack-ability of heavy feed material derived from atmospheric and vacuum distillation bottoms; FCC bottoms, coker bottoms and hydrocracker bottoms. The invention particularly relates to a catalyst cum heat supply product suitable for thermal coking process either in a batch mode or continuous coking process.

Claims

1. A process of preparing a catalyst for cracking of heavy hydrocarbons, wherein the process consists of: a) calcining clay having a surface area between 10-20 m.sup.2/g a temperature in a range of 300950 C.; b) dispersing the calcined clay in about 10% hydrochloric acid solution at a temperature of about 85 C. under agitation for about 3 hours to obtain an acid treated clay; c) filtering the acid treated clay and washing with demineralized water; d) drying to obtain a modified clay; e) preparing a slurry of the modified clay in water using 0.5 wt % dispersant; f) reacting a pseudoboehmite alumina with an acid to obtain an alumina slurry; g) mixing the alumina slurry with the slurry of modified clay to obtain a slurry having a pH of 2.5 and a solid content of 25%; h) spray drying the slurry obtained in step (g) to obtain microspheres having average particle size of 85 microns; i) calcining the spray dried microspheres at a temperature of 550 C. for an hour to obtain the desired catalyst having an ABD (apparent bulk density) of 0.70 g/cc and a surface area of 85 m.sup.2/g.

2. The process according to claim 1, wherein the clay is selected from kaolinite, bentonite, illite, vermiculite, smectite, montmorillonite, sepiolite and hectorite.

3. The process according to claim 1, wherein the acid of step (f) is selected from nitric acid, formic acid or acetic acid.

4. The process according to claim 1, wherein the dispersant is Tamol, which is a neutral sodium salt of an arylsufonic acid.

5. The process according to claim 1, wherein calcining the clay is carried out at a temperature of 950 C.

Description

DESCRIPTION OF INVENTION

(1) The present invention discloses a material is selected for offering required surface area, acidity and pore diameter for sustaining of cracking of heavier hydrocarbons. The material is selected from class of clays, processed for creating required acidity, pore size and surface area insitu.

(2) Further, a suitable binder and matrix is selected for effectively binding high surface area cracking material at the same time capable of offering required heat energy. Adequate inorganic silica in the form of colloidal shape has been employed for enhancing physical properties of catalyst such as bulk density and attrition resistance. Final catalyst when is in the shape of microspheres has ABD in the range 0.75 to 1 g/cc, attrition Index below 6, average pore diameter from 20 to 1,000A.

(3) The new catalytic material of this application offers higher heat required for enduring endothermic cracking reaction and also required weak acid sites for assisting cracking reaction.

(4) As per the invention, the catalyst composition comprises of porous acidic clay bonded by alumina with a diluent normal clay, silica and aluminum trihydrate. The porous acidic clay can be produced insitu after calcination of shaped catalyst from kaolinite, bentonite, vermiculite, smectite, montmorillonite, sepiolite and hectorite. Natural beneficiated, milled clay can be in finely divided form with a size below about 5 microns. Clay can have a two-layer structure having alternating sheets of silica in tetrahedral configuration and alumina in octahedral configuration. These sheets are separated with a gap of 7.13A. Dry atmosphere equilibrated clay has moisture content of about 15 wt %. The clay is a good source for silica and alumina with about 45 wt % of silica and 38 wt % of alumina with empirical formula 2SiO.sub.2Al.sub.2O.sub.3.2H.sub.2O. Clay possesses surface area in the range 10-20 m.sup.2/g and as such does not have any catalytic activity. According to the present invention, this clay has been transformed to porous mild acidic material through high temperature calcination between 500 C. to 1000 C. followed by controlled mineral acid leaching, acid sourced from hydrochloric acid, nitric acid, sulphuric acid, hydrofluoric acid, phosphoric acid and their mixture. Calcined clay can be used or alternately normal clay containing catalyst can be subjected to high temperature calcination while acid leaching is performed on shaped catalyst employing adequate binder and fillers. Acid leaching of catalyst can pores in the range 20-1000A with mild acidity accessible to large hydrocarbon molecules suitable for cracking heavy resin and alkyl aromatics, heavy naphthenic molecules present in heavy feeds.

(5) While, binder can be derived from alumina especially pseudoboehmite grade which is either produced by reaction between acidic and alkaline alumina salts or by alkoxide process. Pseudoboehmite aluminas with soda, less than 0.1 wt % are ideal binders for normal and calcined clays as they are converted to glue by reacting with acids like nitric acid, formic acid or acetic acid. Glue alumina can be mixed with normal/calcined clays with or without other grades of alumina, silica source and can be produced into microspheres by spray drying technique. Other shapes can be given such as pellets, extrudes, tablets and rings employing suitable process. Once spray dried product is calcined, alumina gets transformed into gamma phase, a hard material, which holds clay and other catalyst ingredients together to form attrition resistant mass. Varieties of pseudoboehmite alumina are commercially available in different crystallite sizes and surface area. Besides, pseudoboehmite other alumina such as aluminum trihydrate, bayerit, gel alumina can also be employed as a matrix or partly serving to improve ABD and attrition resistance.

(6) Colloidal silica is aqueous colloidal dispersions of silica particles, stabilized by the use of small quantities of soda or ammonium. These products having soda less than 0.2 wt % and can be readily used for matrix or catalyst binding purpose. These are stable between pH of 8.5 and 11.

(7) The present disclosure provides working examples which are given by way of illustration and should not be construed to limit the scope of the disclosure.

Example 1

(8) This example describes the process for the preparation of ready to react clay. 588 gm kaolin clay with 85% particles size below 3 micron, volatiles 15% was calcined to 950 C. for one hour and cooled to room temperature. Calcined clay was slurried in 500 cc of demineralised water (DM) containing 0.5 wt % dispersant Tamol to obtain free flowing slurry.

Example 2

(9) This example describes a process for the preparation of acidic and porous microspheres required for carrying thermal cracking of heavy residue feed. 214 g of alumina of Pural SB Grade of Sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 972 g of calcined clay slurry with solid content 50% in water prepared as per example 1, above was added under stirring. Final slurry with of 2.7 with solid content 25% was spray dried to obtain microspheres with average particle size 85 microns. Spray dried product was calcined to 550 C. for one hour.

Example 3

(10) Calcined microspheres were dispersed in 10% hydrochloric acid solution at 85 C. and kept under agitation for 3 hours. At the end, acid treated microspheres were recovered by filtration, washed thrice with fresh DM water and oven dried. Over dried product has loss on ignition of 10 wt %, surface area of 135 m.sup.2/g and ABD of 0.77 g/cc.

Example 4

(11) This example refers to a composition where in, acidity and pore creation on clay was performed as post spray drier.

(12) 214 g of alumina of Pural SB Grade of Sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g of normal clay slurry containing 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.7 with solid content 25% was spray dried to obtain microspheres with average particle size 85 microns. Spray dried product was calcined to 950 C. for one hour. Calcined product was cooled to room temperature and dispersed in 10% hot hydrochloric acid at 85 C. and kept agitated for 3 hours. At the end, acid reacted micropsheres were recovered by filtration, washed three times each time with fresh hot DM water. Washed product was oven dried for 12 hours at 120 C. This product showed ABD of 0.78 g/cc, surface area of 145 m.sup.2/g.

Example 5

(13) This example describes the process for the preparation clay in which 800 g clay with volatiles 15% was calcined at different temperature namely 300 C., 500 C. 700 C. and 950 C. for one hour.

Example 6

(14) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g of calcined clay at a temperature of 300 C. slurry containing 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 550 C., 1 hour. The product 150 g was dispersed in 10% 500 ml of Hydrochloric acid and the mixture was subjected to heating at a temperature of 85 C. for 3 hours. At the end, acid reacted microspheres were recovered by filtration, washed three times with fresh hot DM water. Washed product was oven dried for 12 hours at 120 C. This product showed ABD of 0.72 g/cc, surface area of 23 m.sup.2/g.

Example 7

(15) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g of calcined clay at a temperature of 500 C. slurry contain 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 550 C., 1 hour. The product 150 g was dispersed in 10% 500 ml of Hydrochloric acid and the mixture was subjected to heating at a temperature of 85 C. for 3 hours. At the end, acid reacted microspheres were recovered by filtration, washed three times with fresh hot DM water. Washed product was oven dried for pH at 120 C. This product showed ABD of 0.73 g/cc, surface area of 25 m.sup.2/g.

Example 8

(16) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g of calcined clay at a temperature of 700 C. slurry containing 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 550 C., 1 hour. The product 150 g was dispersed in 10% 500 ml of Hydrochloric acid and the mixture was subjected to heating at a temperature of 85 C. for 3 hours. At the end, acid reacted microspheres were recovered by filtration, washed three times with fresh hot DM water. Washed product was oven dried for 12 hours at 120 C. This product showed a ABD of 0.72 g/cc, surface area of 30 m.sup.2/g.

Example 9

(17) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g of calcined clay at a temperature of 950 C. slurry containing 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 550 C., 1 hour. The product 150 g was dispersed in 10% 500 ml of Hydrochloric acid and the mixture was subjected to heating at a temperature of 85 C. for 3 hours. At the end, acid reacted microspheres were recovered by filtration, washed three times with fresh hot DM water. Washed product was oven dried for 12 hours at 120 C. This product showed a ABD of 0.77 g/cc, surface area of 135 m.sup.2/g.

Example 10

(18) This example refers to a composition where in, acidity and pore creation on clay was performed as post spray drier.

(19) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.) To the alumina, 574 g of normal clay slurry contain 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 950 C., one hour. Calcined product was cooled to room temperature and dispersed in 10% hot hydrochloric acid at 85 C. and kept agitated for 3 hours. At the end, acid reacted microspheres were recovered by filtration, washed three times each time with fresh hot DM water. Washed product was oven dried for 12 hours at 120 C. This product showed a ABD of 0.78 g/cc, surface area of 145 m.sup.2/g.

Example 11

(20) This process describes a process for the preparation of modified clay.

(21) 1000 g calcined clay (300 C., 500 C. C., 700 C. and 950 C.) was dispersed in 10% hydrochloric acid solution at 85 to 90 C. and kept under agitation for 3 hours. At the end, acid treated clay was recovered by filtration, washed thrice with fresh hot DM water and oven dried. Oven dried product is called as modified clay.

Example 12

(22) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g modified clay which was calcined at a temperature of 300 C. slurry containing 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 550 C., 1 hour. This product showed ABD of 0.70 g/cc, surface area of 42 m.sup.2/g.

Example 13

(23) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g modified clay which was calcined at a temperature of 500 C., slurry containing 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 550 C., 1 hour. This product showed ABD of 0.71 g/cc, surface area of 35 m.sup.2/g.

Example 14

(24) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g modified clay which was calcined at a temperature of 700 C. slurry containing 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 550 C., 1 hour. This product showed ABD of 0.71 g/cc, surface area of 43.9 m.sup.2/g.

Example 15

(25) 214 g of alumina of pural SB grade of sasol was reacted with 43.9 g of formic acid at room temperature (20 C.). To the alumina, 574 g modified clay which was calcined at a temperature of 950 C. slurry containing 0.5 wt % of dispersant in water was added under stirring. Final slurry with pH of 2.5 with solid content 25% was spray dried to obtain microsphere with average particle size of 85 microns. Spray dried product was calcined to 550 C., 1 hour. This product showed ABD of 0.70 g/cc, surface area of 85 m.sup.2/g.

(26) Performance Evaluation of Catalyst

(27) Performance evaluation was conducted using VR having CCR 23 wt %. Experiments were conducted at three temperature i.e 490, 500 and 510 C. using catalyst formulation at atmospheric pressure.

(28) TABLE-US-00001 TABLE 1 Example 10 Example 10 Example 10 490 500 510 Base + Base + Base + 490 catalyst 500 catalyst 510 catalyst Base (Example 10) Base (Example 10) Base (Example 6) Gas 10 12 12 14 14 15 Liquid 60 68 58 65 55 63 coke 30 20 30 21 31 22 100 100 100 100 100 100

(29) TABLE-US-00002 TABLE 2 In the table performance evaluation was conducted at a temperature of 490 C. using catalyst formulation of examples 6, 9 10 and 15 at atmospheric pressure. Example 10 Example 9 Example 15 Example 6 490 490 490 490 Base + Base + Base + Base + catalyst catalyst catalyst catalyst 490 (Exam- 490 (Exam- 490 (Exam- 490 (Exam- Base ple 10) Base ple 11) Base ple 15) Base ple 6) Gas 10 12 10 11 10 11 10 10 Liq- 60 68 60 67 60 61 60 60 uid coke 30 20 30 22 30 28 30 30 100 100 100 100 100 100 100 100

(30) TABLE-US-00003 TABLE 3 Physico-chemical properties of catalyst compositions: The table provides the properties such as surface area, ABD and average pore diameter of the Examples 5 to 15. Av. pore SA ABD dia. Examples Description m.sup.2/g g/cc (Angstrom) Example 5 Calcination of clay Example 6 Microspheres of Calcined Clay (300 C.) 23 0.72 and Alumina& post leaching Example 7 Microspheres of Calcined Clay (500 C.) 25 0.73 and Alumina & post leaching Example 8 Microspheres of Calcined Clay (700 C.) 30 0.72 and alumina & post leaching Example 9 Microspheres of Calcined Clay (950 C.) 135 0.77 640 and Alumina & post leaching Example 10 Microsphere of clay & Alumina Calined @ 145 0.78 674 950 C., Post Leaching Example 11 Leaching of calcined clay Example 12 Microsphere of Leached clay which is 42 0.70 calcined @300 C. and alumina Example 13 Microsphere of Leached clay which is 35 0.71 calcined @500 C. and alumina Example 14 Microsphere of Leached clay which is 40 0.71 calcined @700 C. and alumina Example 15 Microspheres of Leached Clay and alumina 85 0.70

(31) It is concluded from Table 2 and 3 that the catalysts formed according to examples 9 and 10 where the surface area between 100-200 m.sup.2/gm, ABD of 0.7 to 1 g/cc and average pore diameter in the range of 630 to 680 A would result in reducing coke in the cracking of heavy hydrocarbon.