Title of Invention

"AN IMPROVED PROCESS FOR THE PREPARATION OF FLUID CATALYTIC CRAKING (FCC) CATALYSTS"

Abstract The invention provides to an improved process for the preparation of cracking catalyst using dealuminated Y type zeolite and catalytically active silica-alumina matrix as important components. The invention more particularly provides a process for the preparation of fluid catalytic cracking catalyst using 60% dealuminated zeolite-Y and catalytically active silica-alumina matrix which results in improved catalytic performance with respect to bottoms cracking.
Full Text This invention relates to an improved process for the preparation of fluid catalytic cracking (FCC) catalyst. In particular, the invention relates to a process for the preparation of cracking catalyst using dealuminated Y type zeolite.and catalytically active silica-alumina matrix as important components. The invention more specifically relates to a process for the preparation of fluid catalytic cracking catalyst using 60% dealuminated zeolite-Y and catalytically active silica-alumina matrix which results in improved catalytic performance with respect to bottoms cracking.
Fluid catalytic cracking (FCC) occupies an important place in petroleum refining industry for the conversion of heavier petroleum fractions in to valuable products like LPG, gasoline and middle distillate [Total cycle oil (TCO)] a blanding component for diesel pool. It is well known that heavier feeds are heavily contaminated with metals like vanadium, nickel and iron. These metals particularly vanadium and nickel causes catalyst deactivation and promote undesirable non selective cracking. For the processing of heavier feeds, increase in heat load, higher thermal instability, increased contaminated metals and decreased hydrogen availability dictate the catalyst requirement to meet the following objective :
• Higher thermal and hydrothermal stability
• Enhanced metal tolerance
• High TCO selectivity
• Minimum coke yield
• Increased bottoms cracking i.e. reduced yield of material boiling above 370oC
• Dealuminated zeolite-Y to the appropriate level of dealumination can withstand the process conditions used in the regeneration of coked catalyst and retention of activity and crystallinity of the zeolite part of the FCC catalyst is improved. Mesopores created during dealumination of zeolite are also helpful in the cracking of larger molecules present in the heavier feeds. Dealumination of zeolite results in decrease in unit cell size (UCS) and increase in the silica to alumina ratio of the zeolitic frame work which in turn affects the physico-chemical properties and increase the thermal and hydrothermal stability. Such changes in zeolite composition and properties have a significant impact on catalytic activity, selectivity and stability. The dealumination to the appropriate level also modifies the acidity pattern of the zeolite and hence the activity and coke selectivity. Because of lower concentration of active sites, hydrogen transfer reactions are suppressed and there by produce less coke and more olefinic products resulting in higher olefiniicity of LPG.
The catalytically active matrix serves one valuable purpose i.e. the cracking of larger molecules with increased accessibility of active sites of the matrix to the reacting molecules. The inclusion of active matrix in the catalyst formulation therefore leads to the decrease in the yield of bottoms i.e. the material boiling above 370oC. The active matrix preparation based on either silica-alumina gel prepared by sodium containing ingredients as a source of silica and alumina or aluminia sol prepared by alumina chlorohydrate suffers the of low apparent bulk density (ABD), poor attrition resistance due to low solid content of the catalyst slurry at pumpability for the spray drying, lower product yield due to losses incurred in the washing steps involved during the removal of impurities.
The matrix prepared by the process of the present invention based on silica alumina sol prepared by using soda free materials like commercially available silica sol and disperal alumina hydrate. The FCC catalyst prepared by the process of the present invention does not require gelation time for interaction between Si-Al bond to generate appropriate acidity and pore size as the dispersal alumina hydrate itself is acidic and contain larger pores required for the cracking of larger molecules present in the heavier feedstocks. The advantages of the present invention for the preparation of FCC catalyst over the known processes in the prior art are as follows :
1. FCC catalyst slurry using the active matrix prepared by the process of the
present invention meets the pumpable characteristics required for spray
drying.
2. Solid content of the catalyst slurry is higher, 30% resulting in higher ABD and
attrition properties.
3. The catalyst prepared by the process of the present invention eliminates the
washing steps to remove impurities giving higher product yield improving the
process economics.
4. The catalyst prepared by the process of present invention eliminates the step
of kaolin clay modification.
5. The catalyst prepared by the process of the present invention contain
significantly higher percentage of larger pore in the 50-150 A° region and is
more resistant towards metal deactivation for the processing of heavier feeds
containing larger molecules and heavily contaminated with metal like
vanadium and nickel.
The objective of the present invention is therefore, to provide a process for the preparation of FCC catalyst using 60% dealuminated zeolite-Y and catalytically
active matrix with increased bottoms conversion, better middle distillate and coke selectivity with improved physical properties.
In carrying out the present invention, as a result of extensive research carried out by us, two FCC catalysts were prepared having the same active matrix, dealuminated zeolite Y to 60% level of dealumination with varying zeolite content. The composition of the finished catalyst is presented in detail in Table-Accordingly, the present invention provides an improved process for the preparation of fluid catalytic cracking catalyst which comprises (i) preparing silica -aluminium sol by mixing silica sol with fine powder of alumina in acidified water (water + nitric acid) wherein ratio of silica to alumina is 5 :34.4 and final pH of the sol is maintained at a range 2.7 to 2.8 by adding nitric acid to get homogenous sol, (ii) peptizing dispersal aluminium hydrate from aluminium powder by adding dilute nitric acid ,(iii) preparing 60% dealuminated zeolite -Y by exchanging NaY to NH4Y zeolite with an aqueous solution of ammonium salt such as herein described having strength ranging from 1 to 3N at a temperature in the range of 70°C - 100°C , followed by subjecting NH4Y zeolite to hydrothermal treatment in the presence of 100% steam in the temperature range of 550°C to 650°C for the duration of 0.5 to 1.5 hours to achieve 60% dealumination,(iv) dispersing 25 to 30% of obtained 60% dealuminated zeolite -Y in a silica - alumina active matrix consisting of 40% of silica alumina sol as obtained above, 10% peptized alumina and 20-25% kaolin clay,(v) treating with lanthanum nitrate so as to get 1.0 - 3.0% lanthanum exchanged,(vi) filtering, washing, drying the resultant by conventional manner and then calcining at a temperature in the range of 400°C to 600°C to get the desired FCC catalyst.
In an embodiment of the present invention, the concentration of the ammonium salt solution is so adjusted to provide 2-6 equivalents of the cation per equivalent of total base exchange capacity.
According to an embodiment of the present invention exchange of NaY zeolite to the NH4Y zeolite is affected by treatment with an aqueous solution of ammonium salt generally of 1-3 N strength at a temperature in the range of 70-100°C. salt such as that of ammonium chloride sulfate or nitrate preferably ammonium nitrate may be used. This step is required to bring down the sodium content to less than 1 %, where the concentration of the ammonium salt solution is so adjusted to have 2-6 equivalents of the cation per equivalent of total base exchange capacity. The NH4 Y zeolite formed is heated to a temperature in the range of 550 to 650°C over a period of 0.5 to 1.5 hours in presence of steam in a specified and controlled manner to achieve a degree of dealumination to 60%. The dealuminated zeolite-Y obtained from the step
(b) is treated with mineral acid to further enhance the crystallinity and pore size of the zeolite-Y and reducing sodium content to less than 0.1%. The concentration of the acid in the range of 0.1 to 6N is so chosen that it does not affect the frame work aluminium. The acid used may be selected from any mono basic acid like hydrochloric acid or nitric acid. The dealuminated zeolite-Y was
then dispersed in active matrix prepared by the process of the present invention. Silica-alumina sol and peptized alumina constituted the active matrix. The silica-alumina matrix prepared by the process of the present invention is catalytically more active for the cracking of larger molecules present in the heavier FCC feedstocks and is better coke selective and metal resistant.
The fresh catalyst prepared was with nickel and vanadium salt by the well established method, artificially deactivated by hydrothermal treatment at high temperature in presence of steam at predetermined conditions of temperature, duration and steam partial pressure. Hydrothermally deactivated catalyst samples were subjected to detailed evaluation of catalytic activity and product selectivities in Micro Activity Test (MAT) unit at predetermined conditions of temperature, duration of reaction, cat / oil ratio etc.
The may be practiced as illustrated in the following examples, which should not be construed to limit the scope of the present invention. EXAMPLE-1
In a typical procedure, 600 ml commercial silica sol containing 32% silica of pH 9.5 was taken in a separating funnel. The silica sol was mixed slowly in acidified water (1320 ml water +6 ml cone HNO3) by stirring. The final pH of diluted silica sol was 2.4 and silica concentration 10%. 68.8 g of fine powder of disperal alumina was mixed with vigorous stirring. The silica alumina sol was vigorously stirred for 20 minutes to disperse alumina in sol. The pH of silica-alumina sol was maintained between 2.7 to 2.8 by the addition of nitric acid.
The silica-alumina sol prepared above was taken in a bafflled vessel and added slowly 120g kaolin powder (anhydrous basis) with vigorous stirring maintaining the pH of the system at 2.8. After 10 minutes, 180g of 60% delauminated zeolite-Y was added with vigorous stirring maintaining the pH at 2.8. After 10 minutes, 85.7 g of peptized disperal alumina (60 g anhydrous asis) was added with vigorous stirring maintaining the pH ~3.0.
The above slurry was spray dried to get the desired particle size material. The spray dried material was clacined for 2 hours at 350°C.
The catalyst prepared above was exchanged with lanthanum at 85°C for 2 hours. The solid to liquid ratio was kept 1:4. The concentration of lanthanum nitrate solution was 2.3%. The lanthanum exchanged catalyst was filtered, washed and dried in oven at 110°C for 16 hours. The dried material was calcined at 500°C for 2 hours. It was then sieved to get 100-230 mesh size particles.
EXAMPLE-2
In a typical procedure, 600 ml commercial silica sol containing 32% silica of pH 9.5 was taken in a separating funnel. The silica sol was mixed slowly in acidified water (1320 ml water + 6 ml Conc HNO3) by stirring. The final pH of diluted silica sol was 2.4 and silica concentration 10%. 68.8 g of fine powder of the disperal alumina was mixed with vigorous stirring. The silica-alumina sol was vigorously stirred for 20 minutes to disperse alumina in silica sol. The pH of silica-alumina sol was maintained between 2.7 to 2.8 by the addition of nitric acid. The silica alumina sol prepared above was taken in a bafflled vessel and added slowly 150 g of kaolin powder (anhydrous basis) with vigorous stirring maintaining the pH of the system at 2.8. After 10 minutes., 150 g of 60% dealuminated zeolite-Y was added with vigorous stirring maintaining the pH at 2.8. After 10 minutes, 85.7g of peptized disperal alumina (60g anhydrous basis) was added with vigorous stirring maintaining the pH at-3.0.
The above slurry was spray dried to get the desired particle size material. The spray dried material was calcined for 2 hours at 350°C.
The catalyst prepared above was exchanged with lanthanum at 85°C for 2 hours. The solid to liquid ratio was kept 1:4. The concentration of lanthanum nitrate solution was 2.3%. The lanthanum exchanged catalyst was filtered, washed and dried in oven at 110°C for 16 hours. The dried material was calcined at 500°C for 2 hours. It was then sieved to get 110-230 mesh size particles.
The two catalyst samples were hydrothermally deactivated in presence of 100% steam at 788°C for 3 hours and subjected to evaluation under simulated conditions in Micro Activity Test Unit using combined Mathura feed. The activity and product selectivities for the two catalysts are given in Table-2. The results
indicate that at 38% conversion, the two catalyst formulations have coke selectivity in the range of 1.2637 to 1.3337, total cycle oil selectivity in the range of 39.99% to 41.52% and the yield of bottoms i.e material boiling above 370°C in the range of 31.62% to 31.92%, which shows high potential of catalyst formulations for increased bottoms conversion with lower yield of coke and higher yield of total cycle oil.
Table-1 Composition of FCC" Catalysts
(Table Removed)
(Table Removed)





We Claim:
1. An improved process for the preparation of fluid catalytic cracking catalyst which comprises (i) preparing silica -aluminium sol by mixing silica sol with fine powder of alumina in acidified water ( water + nitric acid) wherein ratio of silica to alumina is 5 :34.4 and final pH of the sol is maintained at a range 2.7 to 2.8 by adding nitric acid to get homogenous sol, (ii) peptizing dispersal aluminium hydrate from aluminium powder by adding dilute nitric acid , (iii) preparing 60% dealuminated zeolite -Y by exchanging NaY to NH4Y zeolite with an aqueous solution of ammonium salt such as herein described having strength ranging from 1 to 3N at a temperature in the range of 70°C - 100°C , followed by subjecting NH4Y zeolite to hydrothermal treatment in the presence of 100% steam in the temperature range of 550°C to 650°C for the duration of 0.5 to 1.5 hours to achieve 60% dealumination, (iv) dispersing 25 to 30% of obtained 60% dealuminated zeolite -Y in a silica -alumina active matrix consisting of 40% of silica alumina sol as obtained above, 10% peptized alumina and 20-25% kaolin clay, (v) treating with lanthanum nitrate so as to get 1.0- 3.0% lanthanum exchanged, (vi) filtering, washing, drying the resultant by conventional manner and then calcining at a temperature in the range of 400°C to 600°C to get the desired FCC catalyst.
2. An improved process as claimed in claim 1 wherein the ammonium
salt used in step (iii) is selected from ammonium chloride, sulfate or
nitrate preferably ammonium nitrate.
3. An improved process for the preparation of fluid catalytic cracking
catalyst substantially as herein described with reference to the
examples.

Documents:


Patent Number 231702
Indian Patent Application Number 241/DEL/2000
PG Journal Number 13/2009
Publication Date 27-Mar-2009
Grant Date 08-Mar-2009
Date of Filing 16-Mar-2000
Name of Patentee COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH
Applicant Address RAFI MARG, NEW DELHI-110001, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 SOBHAN GHOSH INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
2 RAJENDRA PRASAD BADONI INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
3 MOOL CHAND INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
4 BABU LAL INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
5 VEMULAPALLI VENKATA DURGA NAGENDRA PRASAD INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
6 NEERAJ ATHEYA INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
7 ANAND SINGH INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
8 JAI KRISHNA GUPTA INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
9 SADANAND DATTATREYA PHATAK INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
10 SURENDRA NATH SURESH INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
11 TURAGA SUNDAR RAMA PRASADA RAO INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
12 UMA SHANKAR INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
13 MANORANJAN SANTRA INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
14 MOHAN PRABHU KUVETTU INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
15 VENKATACHALAM KRISHNAN INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
16 SUKUMAR MANDAL INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
17 SHANKAR SHARMA INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
18 MANI KARTHIKEYAN INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
19 SATISH MAKHIJA INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
20 SANJAY KUMAR RAY INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
21 GANGA SHANKER MISHRA INDIAN OIL CORPORATION (R&D CENTRE) SECTOR-13, FARIDABAD, 121007, INDIA.
22 TURAGA SUNDAR RAMA PRASADA RAO INDIAN INSTITUTE OF PETROLEUM, DEHRADUN-248005, INDIA.
PCT International Classification Number B01J 21/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA