COMPOSITION AND PROCESS FOR PREPARATION OF ATTRITION RESISTANT ADDITIVE SUITABLE FOR CRACKING HYDROCARBON FEED

Abstract

The present invention relates to attrition resistant hydrocarbon cracking catalyst additive composition comprising aluminium phosphate binder for cracking of hydrocarbon molecules to produce light olefins and process of preparation thereof. The present invention further relates to the process of preparation of the aluminium phosphate binder wherein said binder is incorporated into the ZSM-5 additive composition to enhance its attrition resistance property as well as enhance selectivity and activity of additive composition for production of light olefins such as liquefied petroleum gas (LPG).

Claims

1. An attrition resistant hydrocarbon cracking catalyst additive composition comprising an aluminium phosphate binder, wherein said binder is having a surface area in the range of 80-200 m.sup.2/gm in dry form, and zeta potential in the range of 40mv to 60mv.

2. The composition as claimed in claim 1, wherein said composition comprises: a) 10-70 wt % ZSM-5 zeolite; b) 5-12 wt % aluminium phosphate binder; c) 5-20 wt % colloidal silica; d) 10-60 wt % clay; and e) 1-12 wt % phosphate.

3. The composition as claimed in claim 1, wherein said additive has Attrition Index (ASTM D5757) below 5 and ABD above 0.75 g/cm.sup.3.

4. The composition as claimed in claim 1, wherein said aluminium phosphate binder is prepared by reacting an aluminium compound with an acidic phosphate compound and at least one basic phosphate compound.

5. The composition as claimed in claim 4, wherein the aluminium compound is selected from the group comprising of aluminium nitrate, aluminium chloride, aluminium sulfate and aluminium acetate.

6. The composition as claimed in claim 4, wherein the acidic phosphate compound is phosphoric acid and said basic phosphate compound is selected from di-ammonium hydrogen phosphate, mono-ammonium di-hydrogen phosphate or mixture thereof.

7. A process for preparation of an aluminium phosphate binder having surface area in the range of 80-200m.sup.2/gm in dry form, and zeta potential in the range of 40mv to 60mv, wherein said process comprises of reacting an aluminium compound with an acidic phosphate compound and at least one basic phosphate compound.

8. The process as claimed in claim 7, wherein said acidic phosphate compound is phosphoric acid.

9. The process as claimed in claim 7, wherein said basic phosphate compound is selected from di-ammonium hydrogen phosphate, mono-ammonium di-hydrogen phosphate or mixture thereof.

10. The process as claimed in claim 7, wherein said aluminium compound is selected from the group comprising of aluminium nitrate, aluminium chloride, aluminium sulfate and aluminium acetate.

11. A process for preparation of an attrition resistant cracking catalyst additive composition comprising: a) preparing an aluminium phosphate binder solution by adding aqueous solution of a basic phosphate compound to an aluminium phosphate solution, wherein said aluminium phosphate solution is prepared by reacting an aluminium compound with acidic phosphate compound in water under heating; b) preparing phosphated zeolite slurry by adding di-ammonium hydrogen phosphate to zeolite; c) preparing clay-silica-alumina phosphate slurry by adding kaolin clay slurry and ammonium polysilicate to aluminium phosphate binder solution of step (a); d) preparing additive precursor slurry by adding the phosphated zeolite slurry of step (b) to the clay-silica-alumina phosphate slurry of step (c); and e) spray-drying followed by calcinations of the additive precursor slurry of step (d) to obtain the final attrition resistance additive product ready for use to crack the hydrocarbon molecules to produce light olefins.

12. The process as claimed in claim 11, wherein said aluminium compound is selected from the group comprising of aluminium nitrate, aluminium chloride, aluminium sulfate and aluminium acetate, said acidic phosphate compound is phosphoric acid and said basic phosphate compound is selected from di-ammonium hydrogen phosphate, mono-ammonium di-hydrogen phosphate or mixture thereof.

13. The process as claimed in claim 11, wherein said aluminium phosphate binder obtained in step (a) is characterized by surface area in the range of 80-200 m.sup.2/gm in dry form, and zeta potential in the range of '140mv to 60mv.

14. The process as claimed in claim 11, wherein said zeolite is selected from mordenite, ZSM-5, beta, ZSM-11 with silica alumina ratio ranging from 8 to 200.

15. The process as claimed in claim 11, wherein said attrition resistant cracking catalyst additive composition so obtained has Attrition Index (ASTM D5757) below 5 and ABD above 0.75 g/cm.sup.3.

Description

EXAMPLES

Example-1

Additive Prepared as per Example-7 of U.S. Pat. No. 7,517,827 and Increased Zeolite Content from 25 wt % to 40 wt %

[0081] 98.63 gm of Pural SB grade alumina (having loss on ignition of 23.96 wt %) was made into a slurry with 425 gm of Demineralised (DM) water. The slurry was peptized with 21.52 gm of formic acid (85% concentration). 682.72 gm of ZSM-5 zeolite (loss on ignition 12.12 wt %) having silica to alumina molar ratio of 30 was made into a slurry with 700 gm of 10% ammonia solution followed by addition of 27.7 gm phosphoric acid (85%) to produce a zeolite slurry having pH of 7.8. 758.02 gm of kaolin clay (having loss on ignition 14.91 wt %) was made into a slurry with 800 gm DM water and kept under vigorous stirring while 191.53 gm of ortho-phosphoric acid (concentration 85 wt %) was added. Earlier prepared alumina gel and zeolite slurry were added to the clay-phosphate slurry one after another under vigorous stirring. Final slurry having a pH of about 2.9 was spray dried in a counter current spray drier having two fluid nozzles. Spray dried product was calcined at 500 C.

[0082] Calcined additive showed ABD of 0.77 g/cc and ASTM D5757 attrition index of 30. The catalyst is then de-activated and evaluated in Advanced Cracking Evaluation R+ Micro Activity Test unit at 5 wt % concentration level along with base catalyst and feed (Table-1). Physical properties along with performance results are shown in the Table 3 & 4.

Example-2

Preparation of Additive using Aluminium Phosphate as per Example-2 of U.S. Pat. No. 5,286,369

[0083] 83.41 gm of di-ammonium hydrogen phosphate (DAHP) was dissolved in 500 gm of DM water and 454.55 gm of ZSM-5 zeolite (loss on ignition 12 wt %) having silica to alumina molar ratio of 30 was added under stirring to form phosphated zeolite slurry having pH of 7.2. 399.62 gm of kaolin clay (having loss on ignition 14.92 wt %) was made into a slurry with 400 gm DM water and kept under vigorous stirring while 664.45 gm of aluminium phosphate prepared as per the method mentioned in the Example-2 of U.S. Pat. No. 5,286,369 was added followed by addition of 333.33 gm of ammonium poly-silicate to form clay-silica-alumina phosphate slurry. Earlier prepared phosphated zeolite slurry was added to clay-silica-alumina phosphate slurry under vigorous stirring to form final ZSM-5 precursor slurry. The final slurry having a pH <1 was spray dried in a counter current spray drier having two fluid nozzles. Spray dried product was calcined at 500 C.

[0084] Calcined catalyst showed ABD of 0.78 g/cc and ASTM D5757 attrition index of 1.2. The catalyst is then de-activated and evaluated in Advanced Cracking Evaluation R+ Micro Activity Test unit at 5 wt % concentration level along with base catalyst and feed (Table-1). Physical properties along with performance results are shown in the Table 3 & 4. Although the additive possess attrition index of 1.2, however it shows inferior activity.

Example-3

Preparation of Aluminium Phosphate of Current Invention:

[0085] 61.25 gm of aluminium nitrate (Al (NO.sub.3).sub.3, 9 H.sub.2O) was dissolved in 17.98 gm of DM water and heated the solution at 80 C. after addition of 5.93 gm of phosphoric acid to form solution A. The temperature of the solution A was bringing down to room temperature before preparation of final aluminium phosphate solution. 6.79 gm of di-ammonium hydrogen phosphate was dissolved in 8.05 gm DM water to form a Solution B. Solution B was added gradually to the solution A under stirring to form final aluminium phosphate solution ready for use in the preparation of ZSM-5 additive. Thus the prepared aluminium phosphate solution has zeta potential 50 mv. Further the prepared aluminium phosphate has surface area more than 80 m.sup.2/gm when oven dried at 120 C. followed by calcinations at 500 C. for 1 hr.

TABLE-US-00002 TABLE 2 Binder AlPO.sub.4 Preparation Example-1&2 of U.S. Pat. No. 5,286,369 Current invention Binder preparation Wt % Wt % Composition of solution A Al(NO.sub.3).sub.39H.sub.2O 43.17-45.92 61.25 DM Water 36.29-45.51 17.98 H.sub.3PO.sub.4 11.31-17.79 5.93 Composition of solution B DM Water 0 8.05 (NH.sub.4).sub.2HPO.sub.4 0 6.79 Total 100 100 Surface Area, m.sup.2/gm <5 >80

Example-4

Preparation of Additive using Aluminium Phosphate Prepared as per Example-3 of Current Invention with 40 wt % Zeolite Concentration

[0086] 83.41 gm of di-ammonium hydrogen phosphate (DAHP) was dissolved in 500 gm of DM water and 454.55 gm of ZSM-5 zeolite (loss on ignition 12 wt %) having silica to alumina molar ratio of 30 was added under stirring to form phosphated zeolite slurry having pH of 7.2. 399.62 gm of kaolin clay (having loss on ignition 14.92 wt %) was made into a slurry with 400 gm DM water and kept under vigorous stirring while 664.45 gm of aluminium phosphate as prepared under

[0087] Example-3 was added followed by addition of 333.33 gm of ammonium polysilicate to form clay-silica-alumina phosphate slurry. Earlier prepared phosphated zeolite slurry was added to clay-silica-alumina phosphate slurry under vigorous stirring to form final ZSM-5 precursor slurry. The final slurry having a pH of about 1.3 was spray dried in a counter current spray drier having two fluid nozzles. Spray dried product was calcined at 500 C.

[0088] Calcined additive has ABD of 0.79 g/cc and ASTM D5757 attrition index of 2.92. The additive is then de-activated and evaluated in Advanced Cracking Evaluation R+ Micro Activity Test unit at 5 wt % concentration level along with base catalyst and feed (Table-1). Physical properties along with performance results are shown in the Table 3 & 4. The additive shows high LPG selectivity

Example-5

Preparation of Additive using Aluminium Phosphate Prepared as per Example-3 of Current Invention with 50% Zeolite Concentration

[0089] 83.41 gm of DAHP was dissolved in 625 gm of DM water and 568.18 gm of ZSM-5 zeolite (loss on ignition 12 wt %) having silica to alumina molar ratio of 30 was added under stirring to form phosphated zeolite slurry having pH of 7.5. 282.09 gm of kaolin clay (having loss on ignition 14.92 wt %) was made into a slurry with 300 gm DM water and kept under vigorous stirring while 664.45 gm of aluminium phosphate as prepared under Example-3 was added followed by addition of 333.33 gm of ammonium poly-silicate to form clay-silica-alumina phosphate slurry. Earlier prepared phosphated zeolite slurry was added to clay-silica-alumina phosphate slurry under vigorous stirring to form final ZSM-5 precursor slurry. The final slurry having a pH of about 1.4 was spray dried in a counter current spray drier having two fluid nozzles. Spray dried product was calcined at 500 C.

[0090] Calcined additive has ABD of 0.78 g/cc and ASTM D5757 attrition index of 3.5. The additive is then de-activated and evaluated in Advanced Cracking Evaluation R+ Micro Activity Test unit at 5 wt % concentration level along with the base catalyst and feed (Table-1). Physical properties along with performance results are shown in the Table 3 & 4. The additive shows high LPG selectivity.

Example-6

Preparation of Additive using 14 wt % Aluminium Phosphates Prepared as per Example-3 of Current Invention and with 40 wt % Zeolite Concentration

[0091] 83.41 gm of DAHP was dissolved in 500 gm of DM water and 454.55 gm of ZSM-5 zeolite (loss on ignition 12 wt %) having silica to alumina molar ratio of 30 was added under stirring to form phosphated zeolite slurry having pH of 7.2. 352.61 gm of kaolin clay (having loss on ignition 14.92 wt %) was made into a slurry with 370 gm DM water and kept under vigorous stirring while 930.23 gm of aluminium phosphate as prepared under Example-3 was added followed by addition of 333.33 gm of ammonium poly-silicate to form clay-silica-alumina phosphate slurry. Earlier prepared phosphated zeolite slurry was added to clay-silica-alumina phosphate slurry under vigorous stirring to form final ZSM-5 precursor slurry. The final slurry having a pH of about 1.2 was spray dried in a counter current spray drier having two fluid nozzles. Spray dried product was calcined at 500 C.

[0092] Calcined additive has ABD of 0.79 g/cc and ASTM D5757 attrition index of 2.5. The additive is then de-activated and evaluated in Advanced Cracking Evaluation R+ Micro Activity Test unit at 5 wt % concentration level along with the base catalyst and feed (Table-1). Physical properties along with performance results are shown in the Table 3 & 4. The additive shows inferior LPG selectivity.

TABLE-US-00003 TABLE 3 Additive composition and their physical properties Example-1 Prepared as per U.S. Pat. No. 7,517,827 Example-2 Example-4 Example-5 Example-6 Binder AlPO4, wt % 0 10 (Prepared 10 (Prepared 10 (Prepared 14 (Prepared as per U.S. as per as per as per Pat. No. Example 3) Example 3) Example 3) 5,286,369 PSB Alumina 5 0 0 0 0 Zeolite, wt % 40 40 40 50 40 Clay, wt % 43 34 34 24 30 H.sub.3PO.sub.4 (as PO.sub.4), wt % 12 0 0 0 0 (NH.sub.4).sub.2HPO.sub.4 as PO.sub.4. Wt % 0 6 6 6 6 SiO.sub.2 0 10 10 10 10 ABD, gm/cc 0.77 0.78 0.79 0.78 0.79 Attrition Index, 12 1.20 2.92 3.5 2.5 ASTM D5757

TABLE-US-00004 TABLE 4 Performance results of additive prepared as per examples 1 to 6 Base Catalyst + Base Catalyst + Base Catalyst + Base Catalyst + Base Catalyst + 5 wt % Additive of 5 wt % Additive of 5 wt % Additive of 5 wt % Additive of 5 wt % Additive of Example-1 Example-2 Example-4 Example-5 Example-6 Cat/oil 7.52 7.52 7.52 7.52 7.52 220 C. 81.93 80.77 82.20 82.50 81.11 Conversion, wt % Coke 8.03 7.99 7.95 7.83 8.36 DG 2.30 2.33 2.36 2.41 2.12 LPG 27.68 25.74 27.80 28.27 26.15 Gasoline (C5-150) 33.24 34.41 34.32 34.16 34.63 HN (150-220) 10.68 10.23 9.77 9.83 9.85 LCO (220-370) 13.77 14.98 13.60 13.48 13.98 Bottom (370+) 4.30 4.32 4.20 4.02 4.91

[0093] The examples 3, 4 & 5 were prepared based on present invention. The example-3 teaches the preparation of novel aluminium phosphate binder. Examples 4 & 5 were the final additive product prepared based on example 3. The performance of examples 4 & 5 shows better LPG selectivity.