Catalyst additive composition for catalytic cracking and a process of preparation thereof

Abstract

The present invention relates to a catalyst additive composition suitable for fluid cracking, riser cracking and fixed bed cracking with reduction in bottom and coke, wherein the aluminosilicate and silica-alumina is generated in situ from added clay and silica. The present invention is also directed towards the preparation of the said catalyst additive composition. The invention also discloses a process for cracking of heavy hydrocarbons using the said catalyst additive.

Claims

1. A catalyst additive composition comprising 10-40 wt % of calcined clay, 10-40 wt % of diluent clay, 10-30 wt % of silica, 1-30 wt % of alumina, and less than 0.3 wt % sodium, wherein the catalyst additive has a surface area of 140 to 165 m.sup.2/g, average pore diameter of 80 to 86 A, apparent bulk density (ABD) of 0.7 to 1 g/cc, an attrition index below 10 and has a pore volume in the range of 0.2 to 0.4 cc/gm, wherein the calcined and diluent clays are selected from kaolinite, illite, vermiculite, smectite, and sepiolite.

2. The catalyst additive as claimed in claim 1, wherein an aluminosilicate is generated in situ from the alumina and silica.

3. The catalyst additive as claimed in claim 1, wherein 10 to 40% of volume of the additive is contributed by pores in the range of 10-100 ? and 10 to 40% of volume is contributed by pores in the range of 100 to 2000 ?.

4. The catalyst additive as claimed in claim 1, wherein the smectite is bentonite.

5. The catalyst additive as claimed in claim 1, wherein the silica is selected from ammonia or sodium stabilized colloidal silica having less than 0.3 wt % residual soda, sodium silicate and tetraethyl orthosilicate.

6. The catalyst additive as claimed in claim 1, wherein the alumina is selected from alumina trihydrate, bohemite, pseudoboehmite, alumina sol and alumina gel.

7. A process for catalytic cracking with the catalyst additive of claim 1, wherein the process comprises contacting a feed with the catalyst as claimed in claim 1 under reaction temperature of 510-540? C. and feed sourced from atmospheric and vacuum distillation bottoms; FCC bottoms, coker bottoms and hydrocracker bottoms, to obtain LPG up to 27%, gasoline in the range of 35-37%, reduction in coke in the range of 2-5 wt %, and bottoms below 5 wt %.

8. A process for catalytic cracking with the catalyst additive of claim 1, wherein the process comprises catalytically cracking a feed sourced from resid under a reaction temperature of 540-580? C., the said catalyst additive produces LPG up to 32%, gasoline in the range of 23-25% and reduction in coke between 2-5 wt %.

Description

BRIEF DESCRIPTION OF DRAWING

(1) FIG. 1: Pore Size distribution of Additive under Example-2 as per present invention.

DESCRIPTION OF THE INVENTION

(2) The present invention discloses a catalyst additive composition suitable for fluid cracking, riser cracking and fixed bed cracking in which high value olefins can be significantly enhanced. The present invention also discloses a process of preparation of the said catalyst additive composition and a process employing the said catalyst additive for enhancing the production of LPG, Propylene, gasoline, diesel and reduction of undesired coke and bottom.

(3) An aspect of the present invention discloses a process for preparing a catalyst additive characterized in that the silica-alumina and aluminosilicate matrix required for cracking of residue and heavy hydrocarbons are generated in-situ rather than adding externally in the process. This process alter the acid sites in the range of 0.158 to 0.168 mmol/g and generates the defects/porosity in the cracking components which in turn enhance yield of desired products such as gasoline, olefin and reduces coke and bottom.

(4) In an embodiment of the present invention, a catalyst additive composition is disclosed comprising, 10-40 wt % of reacted clay, 10-40 wt % of diluent clay, 10-30 wt % of silica, 1-30 wt % of alumina, less than 0.3 wt % sodium. In another embodiment of the present invention, a catalyst additive composition is disclosed comprising, 10-40 wt % of reacted clay, 10-40 wt % of diluent clay, 10-30 wt % of silica, 1-30 wt % of alumina, less than 0.3 wt % sodium wherein the aluminosilicate is generated in situ from alumina and silica.

(5) In accordance with the present invention, the prepared catalyst additive has surface area of 140 to 165 m.sup.2/g, average pore diameter of 80 to 86 ?, acidity of 0.158 to 0.168 (mmol/g) apparent bulk density (ABD) of 0.7 to 1 g/cc, an attrition index below 10 and has a pore volume in the range of 0.2 to 0.4 cc/gm. Also, in accordance with the present invention, a catalyst additive suitable for fluid cracking, riser cracking and fixed bed cracking is disclosed wherein 10 to 40% of pore volume of the catalyst additive is contributed by pores in the range of 10-100 ? and 10 to 40% of pore volume is contributed by pores in the range of 100 to 2000 ?.

(6) In accordance with the present invention, the source of reacted clay and diluent clay is selected from kaolinite, bentonite, illite, vermiculite, smectite, montmorillonite, sepiolite and hectorite. Further in accordance with the present invention, the silica is selected from ammonia or sodium stabilized colloidal silica having less than 0.3 wt % residual soda, sodium silicate and tetraethyl orthosilicate. The alumina used in accordance with the present invention is selected from alumina trihydrate, bohemite, pseudoboehmite, alumina sol and alumina gel.

(7) A process for preparing the catalyst additive suitable for fluid cracking, riser cracking and fixed bed cracking is disclosed, said process comprising calcining clay at 500-1000? C., optionally modifying the reacted clay with acid and adding dilute acid to the reacted clay. The reacted clay-acid mixture is cooled, and sodium silicate, diluent clay and optionally alumina are added to the reacted clay acid mixture. The mixture is then dried to obtain the catalyst additive.

(8) In an embodiment of the invention, process for preparing the catalyst additive suitable for Fluidized Catalytic Cracking process is disclosed wherein the aluminosilicate is generated in situ, employing 10-40 wt % of reacted clay, 10-40 wt % of diluent clay, 10-30 wt % of silica, and 1-30 wt % of alumina.

(9) In yet another aspect of the present invention, a process for cracking of heavy hydrocarbons using prepared catalyst additive is disclosed with steps comprising, contacting a feed with the catalyst additive under reaction temperature of 510-540? C. and feed sourced from atmospheric and vacuum distillation bottoms; FCC bottoms, coker bottoms and hydrocracker bottoms, catalyst additive produces LPG up to 27 wt %, gasoline in the range of 35-37 wt %, reduction in coke in the range of 2-5 wt %, and bottoms below 5 wt %.

(10) In an embodiment of the present invention, a process for cracking of heavy hydrocarbons using prepared catalyst additive is disclosed wherein under reaction temperature of 540-580? C. and feed sourced from resid, the said catalyst additive produces LPG up to 32 wt %, gasoline in the range of 23-25 wt % and reduction in coke between 2-5 wt %.

(11) Having described the basic aspects of the present invention, the following non-limiting examples illustrate specific embodiment thereof.

EXAMPLES

(12) Feed Stocks:

(13) The feed stocks used in the present invention are the residual fractions having metals (Ni+V) less than 40 ppm. Table-1 gives the properties of feed stock used in this invention.

(14) TABLE-US-00001 TABLE 1 Properties of Feed Cases-1 & 2 Sr. No. Attributes Unit Feed-1 Feed-2 1 Density @ 15? C. g/cc 0.887 0.928 2 Kinematic Viscosity @ Cst 7.4 100? C. 3 Distillation, D-1160 4 IBP ? C. 162 5 5% ? C. 267 6 30% ? C. 370 7 50% ? C. 409 8 70% ? C. 457 9 Sulphur wt % 1.72 10 Total N.sub.2 ppm 860 11 CCR wt % 3.3 3.0 12 V ppm 23 <1 13 Ni ppm 9 <1 14 Na ppm 1.8 <1 15 Fe ppm 2.4 <1 16 Paraffin Wt % 46.8 17 Naphthene Wt % 21.6 18 Aromatics Wt % 31.6

Example 1

(15) a. 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 in the range of 13-18 wt % was calcined to 500-1000? C. for one hour and cooled to room temperature. b. Clay prepared as per the procedure mentioned in Example-1(a) was modified with acid like sulfuric acid, hydrochloric acid, nitric acid, formic acid and acetic acid at 50-100? C. for 3-5 hours.

Example 2

Preparation of Cracking Catalyst Additive with Enhanced Olefin, Gasoline with Reduced Coke and Bottom

(16) This example describes the process for the preparation of catalyst additive microspheres. 707 gm of neutral grade sodium silicate was dilutes with 707 gm of chilled DM (4? C.). 333 gm of sulfuric acid (30%) was diluted with 333 gm of DM water and maintained at 95? C. and vigorous stirring, while to this, 450 gm of clay prepared as per the procedure mentioned in Example-1(a). Calcined clay-acid mixture was cooled to 18? C., and to this 1380 gm of dilute sodium silicate solution was added at the 50-100 gm/minute through an immersed air atomization spray nozzle under vigorous stirring between 1000-3000 rpm. During the process of addition of silicate, 352 gm diluent clay having LOI of 15 wt % was also added. Final slurry having pH of 3 was spray dried in a counter current spray dryer at inlet temperature of 375? C. and outlet temperature of 12? C. Spray dried product was sieved to +20, ?120 micron for further processed. 500 gm of spray dried product was dispersed in hot DM water, recovered by filtration reslurried twice with hot DM water, filtered and cake was oven dried to obtained as ready to use catalyst additive suitable for enhancing yield of olefins, enhanced gasoline and reduction in bottoms. Catalyst additive product has ABD of 0.78 gm/cc, attrition index of 5. The pore volume 0.32 cc/gm comprising 10-40% volume contributed by pores in the range 10-100 ? and 10-40% volume contributed by pores in the range 100-2000 ?.

(17) TABLE-US-00002 TABLE 2 Properties of Additive in example-2. S. No Additive in example-2 Properties 1 SA (m.sup.2/g) 165 m.sup.2/g 2 Average pore dia by BET (?) 86 3 Pore volume (cc/g) 0.32 4 Acidity (mmol/g) 0.168

Example 3

(18) This example describes the process for the preparation of catalyst additive microspheres employing sodium stabilized colloidal silica. 333 gm of sulfuric acid (30%) was diluted with 333 gm of DM water and maintained at 95? C. and vigorous stirring, while to this, 450 g clay prepared as per the procedure mentioned in Example-1(a) is said as calcined clay-acid mixture was cooled to 18? C., and to this 833 gm of sodium stabilized colloidal silica was added at the 50-100 gm/minute through a immersed air atomization spray nozzle under vigorous stirring between 1000-3000 rpm. During the process of addition of silicate, 352 gm diluent clay having LOI of 15 wt % was also added. Final slurry having pH of 3 was spray dried in a counter current spray dryer at inlet temperature of 375? C. and outlet temperature of 12? C. Spray dried product was sieved to +20, ?120 micron for further processed. 500 gm of spray dried product was dispersed in hot DM water, recovered by filtration reslurried twice with hot DM water, filtered and cake was oven dried to obtained as ready to use catalyst additive suitable for enhancing yield of olefins, enhanced gasoline and reduction in bottoms. Catalyst additive product has ABD of 0.65 gm/cc, attrition index of 10.

Example 4

(19) This example describes the process for the preparation of catalyst additive microspheres employing Ammonium stabilized colloidal silica. 333 gm of sulfuric acid (30%) was diluted with 333 gm of DM water and maintained at 95? C. and vigorous stirring, while to this, 450 gm clay prepared as per the procedure mentioned in Example-1(a) was added and maintained for 3 hours. Calcined clay-acid mixture was cooled to 18? C., and to this 833 gm of ammonium stabilized colloidal silica was added at the 50-100 gm/minute through an immersed air atomization spray nozzle under vigorous stirring between 1000-3000 rpm. During the process of addition of silicate, 352 gm diluent clay having LOI of 15 wt % was also added. Final slurry having pH of 3 was spray dried in a counter current spray dryer at inlet temperature of 375? C. and outlet temperature of 12? C. Spray dried product was sieved to +20, ?120 micron for further processed. 500 gm of spray dried product was calcined at 550? C. to obtained as ready to use catalyst additive suitable for enhancing yield of olefins, enhanced gasoline and reduction in bottoms. Catalyst additive product has ABD of 0.71 gm/cc, attrition index of 10.

(20) From the Examples 2-4, in-situ modification of clay in presence of silica followed by forming microsphere with diluent clay found to be suitable product with the required Physico-chemical properties and the catalyst additive prepared based on example-2 capable of enhancing propylene rich LPG, gasoline & diesel and to reduce coke and bottom. Therefore procedure described in example-2 employed for preparation of the catalyst additive in following examples.

Example 5

(21) This example describes the process for the preparation of catalyst additive microspheres. 707 gm of neutral grade sodium silicate was dilutes with 707 gm of chilled DM (4? C.). 333 gm of sulfuric acid (30%) was diluted with 333 gm of DM water and maintained at 95? C. and vigorous stirring, while to this, 450 gm of clay calcined at 950? C. and reacted with an acid was added and maintained for 3 hours. Reacted clay-acid mixture was cooled to 18? C., and to this 1380 gm of dilute sodium silicate solution was added at the 50-100 gm/minute through an immersed air atomization spray nozzle under vigorous stirring between 1000-3000 rpm. During the process of addition of silicate, 176 gm diluent clay having LOI of 15 wt % and 180 g bohemite alumina having LOI 17 wt % were also added. Final slurry having pH of 3 was spray dried in a counter current spray dryer at inlet temperature of 375? C. and outlet temperature of 12? C. Spray dried product was sieved to +20, ?120 micron for further processed. 500 gm of spray dried product was dispersed in hot DM water, recovered by filtration reslurried twice with hot DM water, filtered and cake was oven dried to obtained as ready to use catalyst additive suitable for enhancing yield of olefins, enhanced gasoline and reduction in bottoms. Catalyst additive product has ABD of 0.70 gm/cc, attrition index of 7.

Example 6

(22) This example describes the process for the preparation of catalyst additive microspheres. 707 gm of neutral grade sodium silicate was dilutes with 707 gm of chilled DM (4? C.). 333 gm of sulfuric acid (30%) was diluted with 333 gm of DM water and maintained at 95? C. and vigorous stirring, while to this, 450 gm of clay reacted at 950? C. was added and maintained for 3 hours. Reacted clay-acid mixture was cooled to 18? C., and to this 1380 gm of dilute sodium silicate solution was added at the 50-100 gm/minute through an immersed air atomization spray nozzle under vigorous stirring between 1000-3000 rpm. During the process of addition of silicate, 176 gm diluent clay having LOI of 15 wt % and 202 gm Aluminum trihydrate alumina having LOI 26 wt % were also added. Final slurry having pH of 3 was spray dried in a counter current spray dryer at inlet temperature of 375? C. and outlet temperature of 12? C. Spray dried product was sieved to +20, ?120 micron for further processed. 500 gm of spray dried product was dispersed in hot DM water, recovered by filtration reslurried twice with hot DM water, filtered and cake was oven dried to obtained as ready to use catalyst additive suitable for enhancing yield of olefins, enhanced gasoline and reduction in bottoms. Catalyst additive product has ABD of 0.67 gm/cc, attrition index of 7.

Example 7

(23) This example describes the process for the preparation of catalyst additive microspheres with pre-modified clay. 707 gm of neutral grade sodium silicate was dilutes with 707 gm of chilled DM (4? C.). 333 gm of sulfuric acid (30%) was diluted with 333 gm of DM water and maintained at 95? C. and vigorous stirring, while to this, 450 gm of clay prepared as per the procedure mentioned in Example-1(b) 1380 gm of dilute sodium silicate solution was added at the 50-100 gm/minute through a immersed air atomization spray nozzle under vigorous stirring between 1000-3000 rpm. During the process of addition of silicate, 352 gm diluent clay having LOI of 15 wt % was also added. Final slurry having pH of 3 was spray dried in a counter current spray dryer at inlet temperature of 375? C. and outlet temperature of 12? C. Spray dried product was sieved to +20, ?120 micron for further processed. 500 gm of spray dried product was dispersed in hot DM water, recovered by filtration reslurried twice with hot DM water, filtered and cake was oven dried to obtained as ready to use catalyst additive suitable for enhancing yield of olefins, enhanced gasoline and reduction in bottoms. Catalyst additive product has ABD of 0.67 gm/cc, attrition index of 7.

(24) TABLE-US-00003 TABLE 3 Performance evaluation with Feed Case-2 Catalyst *Catalyst-G + Additive of Example-2 (Additive Catalyst-G + Catalyst-G + Catalyst-G + Catalyst-G + prepared as commercial Additive Additive of Additive of per present additive of Example-5 Example-6 Example-7 invention) Cat/oil 5.0 Reaction 545? C. Temperature Dry gas 6.60 7.11 7.16 7.14 5.8 LPG 25.11 25.22 25.4 25.61 26.14 Gasoline 26.02 23.73 24.65 24.31 27.34 (C5-150C) Naphtha 6.78 6.97 6.61 6.74 6.59 LCO 15.47 15.74 15.33 15.57 16.07 DCO 8.68 9.02 9.01 8.72 8.72 Coke 11.34 12.21 11.84 11.91 9.34 216 75.85 75.24 75.66 75.71 75.21 Conversion

(25) Table-3 indicates that the performance of catalyst composition (Catalyst-G+Additive of Example-2) prepared as per present invention is better than other catalyst composition w.r.to LPG & Gasoline yields and reduces low value products yields like dry gas and coke.

(26) Table 3A shows performance of Catalyst-I+Additive of Example-2 in comparison with Catalyst-I+Commercial additive is shown. LPG and Gasoline increase by 1 wt % in case of Catalyst-I+Additive of Example-2 compared to Catalyst-I+Commercial additive.

(27) TABLE-US-00004 TABLE 3A Performance evaluation with Feed Case-2: Catalyst Catalyst-I + commercial Catalyst-I + Additive of additive (Additive-H) Example-2 Cat/oil 5.0 Reaction 545? C. Temperature Dry gas 7.0 6.9 LPG 23.89 25 Gasoline 25.11 26.06 Naphtha 7.25 6.85 LCO 15.8 15.47 DCO 9.02 9.12 Coke 12 10.61 216 Conversion 75.38 75.42

(28) Table-3A indicates that the performance of catalyst composition Catalyst-I+Additive of Example-2 prepared as per present invention is better than other catalyst composition w.r.to LPG & Gasoline yields and reduces low value coke yield.

Example 8

(29) This example describe the performance of cracking catalyst additive component whose preparation is described in example 2 at 5 wt % level with FCC catalyst. The prepared catalysts were impregnated with 6852 ppm vanadium employing vanadium naphthanate, 2200 ppm of nickel employing nickel naphthanate by Mitchell method, followed by hydrogen reduction and hydrothermal deactivation at 788? C. for 3 hours. The performance evaluation was carried out with the process parameters of table 4 in ACER+MAT unit at 510? C. employing feed case-1. The results are shown in Table.4 along with the commercial cracking Catalyst-B.

(30) TABLE-US-00005 TABLE 4 process parameters for performance evaluation S. No. Parameters Value 1 Cat/oil ratio in example 8 4.5 2 Reaction Temperature in example 8 510? C. 3 Cat/oil ratio in example 9 5.0 4 Reaction Temperature in example 9 545? C.

(31) In the fluid catalytic cracking process (FCC), the catalyst/catalyst along with additive is being continuously undergone reaction and regeneration step. The feed being processed in FCCU contains more contaminant metals (Ni & V) & Conradson Carbon Residue (CCR) and it will lead to a significantly higher metal level on the catalyst. i. e. >3000 ppm (Ni+V) & coke on the catalyst. During reaction in the reactor, coke along with metal (Ni & V) is deposited on the catalyst which leads to de-activation of the catalyst. This catalyst is then activated in the regenerator by burning the coke and leaving the metals on the catalyst. This catalyst is called as the equilibrium catalyst (E-cat). Therefore, lab deactivation procedures need to be designed to simulate these changes that occur commercially. An appropriate E-cat sample of the same fresh catalyst should be used to design the lab deactivation conditions, which include duration of steam aging, steam partial pressure, metal (Ni & V) and temperature. Therefore, laboratory deactivation protocols have been mainly developed by taking the properties of E-cat as a reference.

(32) Therefore the conversions of fresh catalysts/catalyst along with additives in to equilibrium catalysts/catalyst along with additives are carried out by metal impregnation followed by hydrothermal deactivation.

(33) TABLE-US-00006 TABLE 5 Performance evaluation with Feed Case-1 Catalyst Base FCC FCC catalyst-B + catalyst-B Additive of example 2 Delta value at Feed conversion at Feed Case-1 Feed Case-1 82.46 wt % Reaction 510 510 Temperature ? C. Cat/Oil ratio 4.5 4.5 Dry gas 2.51 2.00 ?0.51 LPG 24.29 26.66 2.37 Propylene in LPG 30 32 2.00 Isobutylene 2.30 2.48 0.18 Gasoline 37.59 37.55 ?0.04 Naphtha 10.44 10.42 ?0.02 LCO 14.14 14.78 0.64 DCO 3.4 2.76 ?0.64 Coke 7.63 5.83 ?1.80 216 Conversion 82.46 82.46

(34) Table-5 indicates that the performance of catalyst composition (FCC catalyst-B+Additive of example 2) prepared as per present invention is better than the base FCC catalyst w.r.to LPG, Propylene, diesel yields and reduces low value products like coke & dry gas yields.

Example 9

(35) This example describes the performance of cracking catalyst composition comprises catalyst A, B, C, D & E. The details descriptions of the catalysts/additives are given in table-6. However performances of the catalyst compositions are given in table-7.

(36) TABLE-US-00007 TABLE 6 Detailed description of the catalysts/additives Sr. No. Catalyst Name Details description of catalyst 1 Catalyst A Catalyst prepared in the present invention under Example-2 2 Catalyst C Commercial ZSM-5 additive prepared under U.S. Pat. No. 7,656,475 3 Catalyst D Commercial FCC catalyst 4 Catalyst E Commercial additive described in Demel Patent WO97/12011

(37) All these catalyst components are de-activated hydro thermally and its activity was evaluated in fixed bed Auto MAT unit under reaction temperature at 545? C. after preparing their composite mixture. The performance results of the composite catalyst are given in Table 7.

(38) TABLE-US-00008 TABLE 7 Performance evaluation with Feed Case-2 Catalyst (A) + (C) + (D) (Catalyst composition as per Delta (E) + (C) + (D) present invention) value Feed Feed-2 Feed-2 Reaction temperature ? C. Severity, W/F, Min. 1.03 1.02 Dry gas 8.16 7.37 ?0.79 LPG 29.77 31.39 +1.62 propylene 9.03 10.41 +1.38 Propylene in LPG 30.33 33.16 Isobutylene 1.56 1.76 Gasoline 23.91 25.23 +1.32 Naphtha 6.1 6.02 LCO 10.93 10.33 DCO 4.08 5.01 Coke 17.05 14.65 ?2.40 216 Conversion 84.99 84.66 0.33

(39) Table-7 indicates that the performance of catalyst composition [(A)+(C)+(D)] prepared as per present invention is better than the commercial catalyst composition [(E)+(C)+(D)] w.r.to LPG, Propylene, gasoline yields and reduces low value products like coke & dry gas yields.