BRPI1005473A2 - additive for fluid catalytic cracking process catalysts - Google Patents

Abstract

The invention relates to an additive composition for increasing the yield of light olefins in a fluid catalytic cracking process, which exceeds the usual propylene yield limits found in the prior art. Said composition containing ZSM-5 zeolites and Beta zeolites is combined in suitable proportions with typical catalysts for use in fluid catalytic cracking processes, generating higher yields for light olefins, especially propylene.

Description

ADDITIVE FOR CATALYTIC FLUID CRACKING PROCESS CATALYZERS

FIELD OF INVENTION

The present invention finds its field of application among additives for increasing the yield of light olefins in a fluid catalytic cracking process. Preferably, it deals with additives which, combined with the FCC process catalysts, are capable of maximizing propylene production. BACKGROUND OF THE INVENTION In general, the fluid catalytic cracking process is

Widely used for the production of gasoline, light hydrocarbons and especially high value-added olefins. In a scenario of increasing demand for petrochemical raw materials, we seek the maximum production point for light olefins over gasoline production, in order to make the process more economically advantageous for oil refiners.

Thus cracking catalyst additives containing ZSM-5 zeolite have been used to maximize the production of light olefins.

ZSM-5 zeolite has a high silica / alumina ratio and pore opening (approximately 0.55 nm), lower than Y (Faujasite) zeolite, traditionally used in catalytic cracking catalysts.

ZSM-5 zeolite is suitable for processing molecules smaller than their pore diameter. On the other hand, Faujasite zeolite catalyzes hydrogen transfer reactions by forming aromatic compounds that cannot be reversed into light hydrocarbons.

In addition, application of large amounts of additive containing only ZSM-5 zeolite may cause catalytic system activity to fall, an effect known in the art as "dilution". Consequently, the use of catalytic systems containing ZSM-5 and Y zeolites tends to have an upper yield limit for light olefins, particularly for propene.

Thus, it has been the object of study to obtain a catalytic composition capable of expanding the yield limits for light olefins, aiming at their application in catalytic cracking processes.

RELATED TECHNIQUE

Several patent documents are known claiming new additives to increase the yield of light olefins in a fluid catalytic cracking process.

The use of zeolite ZSM-5 as a catalyst additive, for example, is well known to those skilled in the art.

Brazilian patent Pl 8503317 (Tai-Sheng Chou et al.), Incorporated herein by reference, claims the use of said zeolite as an additive for the production of gasoline with a certain octane rating.

U.S. Patent 5,380,690 (Shi Zhicheng et al.), Incorporated herein by reference, discloses a cracking catalyst for the production of light olefins containing from 0% to 70% clay, 5% to 99% inorganic oxides and 1 % to 50% of a zeolite mixture. The zeolite mixture contains from 0% to 25% high silica ratio REY or Y zeolite and 75% to 100% high silica phosphorus or rare earth containing zeolite and a pentasil structure.

European patent EP 0600686 (Eberly, Paul Earl, Jr, et al.), Incorporated herein by reference, discloses a fluid catalytic cracking process in which a low nitrogen and high hydrogen filler is brought into contact with a catalyst containing a mixture of zeolites ZSM-5 and Y. A wide concentration range for said zeolites is claimed.

Brazilian patent application Pl 0605670-9 (Andréa de Rezende Pinho et al.), Incorporated herein by reference, describes an additive for maximizing light olefins in a fluid catalytic cracking process composed of ion exchange modified zeolites with alkaline earth metals.

Similarly, Brazilian patent application Pl 0705179-4 (Alexandre de Figueiredo Costa et al.), Incorporated herein by reference, discloses an additive containing an alkaline earth metal modified zeolite to maximize the production of LPG, propene and isobutene .

Brazilian patent application Pl 0704422-4 (Raquel Bastiani), incorporated herein by reference, discloses an additive containing small pore zeolites, such as ferrierite, for maximizing LPG and propylene in a fluid catalytic cracking process.

The compositions described in the aforementioned documents have some limitations, especially regarding yield for light olefins. It is important to note that the inventions analyzed do not reveal

a new catalytic composition capable of overcoming the usual propylene yield limits imposed by the dilution effect caused by excess ZSM-5 zeolite, and the fact that Faujasite zeolite catalyzes hydrogen transfer reactions by forming aromatic compounds that do not may be reversed into light hydrocarbons. SUMMARY OF THE INVENTION

The invention is an additive composition for increasing the yield of light olefins in a fluid catalytic cracking process which aims to exceed the usual yield limits for propylene imposed by the dilution effect caused by excess zeolite ZSM-5. and hydrogen transfer reactions catalyzed by Faujasite zeolites.

Thus, a composition containing ZSM-5 zeolites and Beta zeolites has been developed which, combined with typical catalysts for use in a fluid catalytic cracking process, yield higher yields for light olefins, especially propylene. DETAILED DESCRIPTION OF THE INVENTION

Detailed description of the additive to increase the yield of light olefins in a fluid catalytic cracking process, object of the present invention, will be based on the following examples.

Generally speaking, the use of higher amounts of ZSM-5 zeolite eventually limits the yield of light olefins. This is mainly due to the absence of light olefin precursors for ZSM-5 action, known in the art as dilution. In addition, secondary reactions occur where the light olefins produced generate oligomers, cyclic and aromatic compounds.

Thus, Beta zeolite-containing additives can act effectively in providing precursors for the action of ZSM-5 zeolite without significantly catalyzing undesirable side reactions.

Beta zeolite contains a three-dimensional large pore channel system circumscribed by 12-tetrahedron rings and can be synthesized directly with a considerably high Si / Al ratio. Its characteristics are high acidity, thermal stability and ease of diffusion of large molecules.

Beta and ZSM-5 zeolites may be incorporated in the form of microspheres suitable for the fluid catalytic cracking (FCC) process, in separate particles or in the same particle. These particles are physically mixed with a typical FCC catalyst in the desired proportions to compose the catalytic systems.

There are several examples of preparation of additives containing ZSM-5 in the specialized technical literature. The following description only illustrates one of the applicable additive preparation methods for the present invention. Other catalytic systems may also be obtained by mixing FCC catalysts with additives prepared by other known methods.

Thus, the additive preparation process comprises the following steps:

Preparation of a suspension containing the desired Beta and ZSM-5 zeolite contents;

Preparation of a pH-inorganic oxide sol, typically of silica, alumina or silica alumina, which forms the composite matrix;

- Mixing the sun of inorganic oxide with the suspension of zeolites and optionally other components as phosphorus compounds

and inert material, such as kaolin, which are also added simultaneously or sequentially to this mixture, followed by maturation of this suspension under conditions that promote interaction between the components in the suspension; e - Drying the suspension by spray dryef.

Optionally, post-treatments such as washes and calcinations may be used. Alternatively, the first suspension may contain only one type of zeolite, either Beta or ZSM-5, and the second type of zeolite may be added to the powder suspension or to a suspension at a later stage.

Thus, the additive to increase the yield of light olefins in a fluid catalytic cracking process, object of the present invention, is formed by Beta zeolite, in a concentration range between 5% and 40% w / w by ZSM-5 zeolite. , in a concentration range of 1% to 55% w / w.

In order that the invention may be better understood and evaluated, the following non-limiting examples will be illustrated below. EXAMPLES

The following examples illustrate the properties of the additive composition for increasing the yield of light olefins in a fluid catalytic cracking process used in varying proportions.

In order to evaluate the yield of FCC1 catalyst additives, the additives of Table 1 were prepared according to the preparation process described above. The indication "n.a." means not analyzed.

TABLE 1 Additive name Z1 Z2 A1 A2 A3 B Zeolite content in additives (%) Beta 0 0 5 10 15 40 ZSM-5 40 55 40 40 40 0 FRX Chemical Analysis (% W / W) SiO2 62.0 68 , 6 64.3 68.2 68.7 63.5 AI2O3 24.5 17.2 22.0 19.6 17.8 22.9 P2O5 11.64 16.8 12.02 10.82 12.41 11 .93 Na2O 0.27 0.00 0.27 0.27 0.27 0.20 Fe2O3 0.93 0.47 0.80 0.66 0.51 0.87 TiO2 0.60 0.35 0.53 0.45 0.35 0.60 Physical properties Bulk density (g / ml) 0.75 0.67 0.74 0.71 0.71 0.59 Micropore volume (mL / g) 0.038 0.047 0.043 0.053 0.057 0.052 Mesoporous Area (m2 / g) 35 28 38 44 57 84 Total Area (rn ^ / g) 117 125 129 158 179 197 Average particle size (μηη) 86 na 69 81 87 95

Prior to catalytic testing, the additives were treated with 100% steam at 788 ° C for 5 hours to simulate the deactivation process that occurs in a commercial FCC unit. In addition, each additive subjected to steam treatment was mixed as an E1 equilibrium catalyst obtained from a commercial unit. The properties of E1 are shown in Table 2. TABLE 2 SiO2 (% w / w) 55.3 AI2O3 (% w / w) 40.1 Na2O (% w / w) 0.53 Re2O3 (% w / w) 2 .48 P2O5 (% w / w) 0.60 Ni (ppm) 3579 V (ppm) 3074 Surface area (m2 / g) 142 Mesoporous area (m2 / g) 30 Micropore volume (ml / g) 0.052

EXAMPLE 1

This example is intended to perform a yield analysis for light olefins according to the state of the art. Additives containing only ZSM-5 (Z1 from Table 1) or ZSM-5 and Beta (A1, A2 and A3 from Table 1) form catalytic systems with ZSM-5 concentration of less than 5% w / w of the final catalyst. For the test, catalyst E1 and a filler whose properties are described in Table 3 were used.

TABLE 3 0API 19.2 Density 0.935 Aniline Point (0C) 83.3 Total Sulfur (% w / w) 0.57 Total Nitrogen (ppm) 2835 Basic Nitrogen (ppm) 854 RCR (%) 0.55 The results of Comparison of catalytic performance of the tested systems at constant conversion of 65% (w / w) and temperature of 535 ° C are consolidated in Table 4.

TABLE4 COMPOSITION 92% E1 + 8% Z1 92% E1 + 8% A1 92% E1 + 8% A2 92% E1 + 8% A3 100% E1 Additive Z1 A1 A2 A3 -% ZSM-5 in the system 3.2 3, 2 3.2 3.2 0% Beta in system O 0.4 0.8 1.2 0 Catalyst / Oil (% w / w) 6.45 6.12 6.17 6.19 6.51 Yield (% w / c) Coke 6.94 6.70 6.83 7.03 7.31 Fuel gas 3.18 3.40 3.24 2.80 2.43 Ethyl 1.31 1.34 1.20 1.14 0.69 LPG 20.2 20.4 20.4 21.4 12.9 Propene 7.94 8.02 7.79 7.83 3.74 Bute 门 os 5.87 5.97 6.27 7.13 4.27 Petrol 34.7 34.5 34.6 33.8 42.4 Distillates Medium 16.7 16.72 16.6 17.0 17 Funds 18.3 18.3 18.3 18.5 18 , 0

The table above shows that propylene and butene are components of LPG and that ethylene is a component of combustible gas.

Comparison between mixtures containing additives A1, A2 and A3 and mixture containing Z1 showed similar propene yield. Butene yield increased and ο ethylene decreased. In addition, there was little change in catalytic activity of the catalyst. Thus, the effect of zeolite admixture additives on yield for Ieves olefins was not significant. EXAMPLE 2

This example proposes to perform an olefin yield analysis in high ZSM-5 catalytic systems.

Thus, the same filler and catalyst (E1) from the previous example were used. However, catalytic systems contain at least 20% of additive Z1, or 8% of crystals of ZSM-5.

The catalytic performance comparison results of the systems tested at constant conversion of 60% (w / w) and temperature of 535 ° C are summarized in Table 5.

TABLE5 COMPOSITION 80% E1 + 20% Z1 70% E1 + 30% Z1 60% E1 + 40% Z1 60% E1 + 30% Z1 + 10% B Additive Z1 Z1 Z1 Z1 eB% ZSM-5 in the system 8 12 16 12 % Beta in System O 0 0 4 Catalyst / Oil (% w / w) 4.90 5.75 7.43 6.70 Yield (% w / w) Coke 4.25 4.28 4.64 4.57 Gas fuel 4.62 5.20 5.66 5.45 Ethyl 2.59 3.30 3.78 3.61 LPG 22.23 22.69 22.84 23.40 Propylene 9.33 9.59 9.58 9 , 88 Butenes 6.66 6.46 6.09 6.49 Gasoline 28.89 27.83 26.86 26.59 Middle Distillates 17.33 16.78 16.12 15.77 Funds 22.67 23.22 23 88 24.23

It can be clearly observed in the table that the increase of Z1

within the mixture caused a drop in conversion, reflected in increased catalyst / oil ratio to maintain the same conversion. Thus, demonstrating the effect of dilution. However, in the same proportion of additive, the mixture containing 60% E1 with 30% Z1 and 10% B was more active than the mixture containing 40% Z1.

Another very important fact shown in the table is that even increasing the Z1 content from 30% to 40% could not increase propylene yield. However, it can be seen that the addition of Beta zeolite, as in the mixture of 10% B with 30% Z1, increased the propene yield, exceeding the threshold.

In general, from the results obtained, it can be stated that the mixture containing 60% E1, 30% Z1 and 10% B has ο higher yield on propylene as well as ο higher yield on light olefins. EXAMPLE 3

This example proposes to perform an analysis of the yield of olefins in high ZSM-5 catalytic systems with a lighter charge and lower aromatics content.

Thus, for example, it uses a load closer than is used to obtain the maximum yield on light olefins to supply the necessary petrochemical inputs. The filler properties are described in Table 6. To compose the catalytic systems a typical FCC commercial catalyst (E2) was used, the properties of which are described in Table 7.

TABLE6 0API 30 Density 0.8721 Aniline Point (0C) 110.5 Total Sulfur (% w / w) 1.41 Basic Nitrogen (ppm) 2.69 RCR (%) 0.05 TABLE7 SiO2 (% w / w) 59.0 Al2O3 (% w / w) 39.4 Na2O (% w / w) 0.30 Re2O3 (% w / w) 0.33 P2O5 (% w / w) 0.00 Ni (ppm) <100 V (ppm) <100 Surface area (m2 / g) 217 Mesoporous area (m2 / g) 73 Micropore volume (ml / g) 0.068

Prior to catalytic testing, the charge was treated with 100% steam at 788 ° C for 5 hours to simulate the deactivation process that occurs in a commercial FCC unit. The catalytic performance comparison results of the systems tested with catalyst / load ratio of 6 and at a temperature of 535 ° C are summarized in Table 8.

TABLE8 COMPOSITION 50% E2 + 50% Z1 50% E2 + 50% Z2 50% E2 + 50% A2 50% E2 50% A3 Additive Z1 Z2 A2 A3% ZSM-5 in the system 20 27.5 20 20% Beta in the system 0 0 5 7.5 Conversion (% w / w) 80.8 80.8 83.2 83.2 Yield (% w / w) Coke 1.47 1.66 1.84 1.88 Fuel gas 4.52 5.69 5.99 4.52 Ethyl 3.49 4.52 4.72 4.32 LPG 32.6 33.9 36.0 35.9 Propene 12.2 12.3 12.5 13.2 Butenes 8 86 8.71 9.38 9.75 Petrol 42.2 39.6 39.3 39.9 Distillates Medium 13.4 13.2 11.4 11.0 Funds 5.84 5.98 5.43 5, 74 Total Yields of Olefins (C2, C3, C4) 24.6 25.5 26.6 27.3

If the 50% Z1-containing mixture is used as a reference, the increase in ZSM-5 content in the Z2-containing mixture system did not significantly change the conversion or yields of propylene and C4 olefins. Thus, it can be concluded that these mixtures reached their yield limits.

However, when Beta zeolite-containing additives were used (50% mixtures of A2 or A3), there was an increase in conversion as well as an increase in total propylene, butene and olefins yields relative to the reference.

The description thus far of the additive to increase the yield of olefins Ieves in a fluid catalytic cracking process, object of the present invention, should only be considered as a possible, or possible embodiments, and any particular features introduced therein should be understood. just as something that has been described for ease of understanding. Accordingly, they may not in any way be construed as limiting the invention, which is limited to the scope of the following claims.

Claims (5)

1.- ADDITIVE FOR CATALYTIC FLUID CRACKING PROCESS CATALYSTALS, containing a mixture of high silicon / aluminum ratio zeolites, characterized in that it comprises: -a Beta type zeolite, in a concentration range between 5% and 40% w / w total catalyst mass; -a zeolite type ZSM-5, in a concentration range between 1% and 55% w / w of the total catalyst mass. 2. An additive for fluid catalytic cracking process catalysts according to claim 1, characterized in that said additive increases the conversion of hydrocarbons to olefins from a catalytic system for FCC. An additive for fluid catalytic cracking process catalysts according to claim 1, characterized in that said additive increases the propylene production of a FCC catalytic system. 4. An additive for fluid catalytic cracking process catalysts according to claim 1, wherein said Beta and ZSM-5 zeolites are incorporated into the FCC catalytic system separately or combined in the same particle. 5. An additive for fluid catalytic cracking process catalysts according to claims 1 and 4, characterized in that said Beta and ZSM-5 zeolites are incorporated in the form of microspheres in the catalytic system for FCC.