CA1289543C - Fcc catalysts of increased effective heat capacity - Google Patents
Fcc catalysts of increased effective heat capacityInfo
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- CA1289543C CA1289543C CA000517224A CA517224A CA1289543C CA 1289543 C CA1289543 C CA 1289543C CA 000517224 A CA000517224 A CA 000517224A CA 517224 A CA517224 A CA 517224A CA 1289543 C CA1289543 C CA 1289543C
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- lithium
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Abstract
ABSTRACT
A catalytic composition for use in fluid catalytic cracking has an effective heat capacity of at least about 0.29 BTU/lb. °F over the range from 950 to 1300°F.
The composition may include microspheres containing in situ crystallized Y-faujasite and fluidizable particles consist-ing essentially of dimagnesium borate. The catalytic composition may include a heat retention component select-ed from the group consisting of dimagnesium borate, aluminum borate, magnesium tetraborate, magnesium ortho-borate, lithim aluminum borate, lithium magnesium borate, lithium aluminum silicate, and lithium aluminate.
A catalytic composition for use in fluid catalytic cracking has an effective heat capacity of at least about 0.29 BTU/lb. °F over the range from 950 to 1300°F.
The composition may include microspheres containing in situ crystallized Y-faujasite and fluidizable particles consist-ing essentially of dimagnesium borate. The catalytic composition may include a heat retention component select-ed from the group consisting of dimagnesium borate, aluminum borate, magnesium tetraborate, magnesium ortho-borate, lithim aluminum borate, lithium magnesium borate, lithium aluminum silicate, and lithium aluminate.
Description
` ~8954~ 2843 FCC CATALYSTS OF INCREASED
EFFECTIVE HEAT CAPACITY
Fluid catalytic cracking is central to modern petroleum refineries. Zeolite containing cracking catalysts efficiently convert less valuable long chain hydrocarbons to more valuable shorter molecules. In many cases, the production of an entire refinery complex is controlled by its Fluid Catalytic Cracking (FCC) unit.
In many cases, especially in older systems, it would be desirable to obtain higher temperatures within the reactor by some means such as increasing the feed pre-heat temperature as this would normally lead to increased conversion, cracked products of higher octane, and the ability to use lower quality feedstocks, but an increase in reactor temperatures would lead to an unacceptable temperature within the regenerator. Thus, the production of the FCC unit and in turn, the refinery, is often limited by the maximum temperature that the construction of the re~enerator can tolerate. Therefore, it is desirable to obtain methods of increasing the FCC
reactor temperature without unduly increasing regenerator temperature.
The method and catalyst compositions of the present $nvention provide for catalytic cracking with improved yields at a constant regenerator temperature and may be used with any conventional zeolitic cracking catalyst but is exceptionally well suited for use with high zeolite catalysts such as those disclosed in U.S.P. 4,493,902.
la Various aspects of this invention are as follows:
A catalytic composition for use in fluid catalytic cracking comprising a zeolite FCC catalyst and a component of higher heat retentiveness in the form of fluidizable particles consisting essentially of inert compounds such that the composition has a heat capacity of at least 1214 J/KgK (0.29 BTU/lb.~F) over the range from 510-705C (950-1300F).
A method of fluidized catalytic cracking using a catalytic composition referred to in the previous paragraph.
According to the present invention, regenerator temperature iB controlled by incorporating a heat reten-tion component into the catalyst composition. The high heat capacity component may either be incorporated into the matrix of the zeolite containing particles or it may be present as separate particles circulating with the .~, I
95~3 zeolite containing particles. In many circumstances, it is advantageous to incorporate the heat capacity in-creasing component both into the matrix of the zeolite containing particles as well as to include separate particles with high heat capacity. There are two primary requirements for the high heat capacity component: it must not destroy zeolite too rapidly, and its effective heat capacity must be in excess of 0.29 BTU/lb.F in the temperature range between the reactor temperature of about 950F and the regenerator temperature of about 1300F. In many cases, it will be advantageous to use a material which upon heating undergoes an endothermic reversible phase change between the reactor temperature and the regenerator temperature. Further, many materials which tend to destroy zeolite too rapidly may be incor-porated into non-zeolite containing particles in the catalytic composition by coating the material with an inert material which prevents or delays the interaction between the zeolite and the heat retention material.
Similarly, zeolite deactivating materials may be incor-porated into the matrix of zeolite containing particles if suitable passivating components are also included.
The preferred heat retention components are fluidizable particles consisting essentially of inert compounds, such as the oxides of lithium, beryllium, boron and magnesium as well as carbon containing compounds of these. The most preferred heat retention composition is dimagnesium borate (2MgO B~03) containing an excess of MgO over the 54 weight % stoichiometric value to ensure that B,03 is immobilized to alleviate interaction with zeolite. This composition is quite inert with respect to zeolite.
Another suitable relatively inert compound is boron carbide (B4C). Other suitable but less inert composi-tions include lithium magnesium borate (Li20 MgO B203), including MgO in excess of 55 weight % stoichiometric value, lithium aluminates (Li20 Al203), including lZ895~3 aluminum oxide in excess of the 80 weight %
stoichiometric value, magnesium borate ~MgO B2O3) containing MgO in less than 54 weight %
stoichiometric value and lithium aluminum silicates (Li2O Al~03 SiO2) containing lithium oxide in less than the 20 weight % stoichiometric value. Other suitable compounds which should normally be encapsulated or otherwise passivated include lithium aluminum borate (2Li,O Al2O3 Bz03), lithium magnesium borates including either boron oxide in excess of the 30 weight %
stoichiometric value or lithium oxide in excess of the 15 weight % stoichiometric value, lithium aluminates (Li~o Al~03) containing lithium oxide in excess of the 20 weight % stoichiometric value, lithium aluminum silicates including lithium oxide in excess of the 20 weight %
stoichiometric value and boron phosphate (B2O3 P,O5).
While these materials can be used to provide increased heat capacity, it will normally be prudent to encapsulate them with a more inert material such as magnesia or alumina to protect the zeolite from premature deactivation due to interaction with the heat retention component. The preferred zeolite for incorporation in the compositions of the present invention is zeolite-Y, i.e. faujasite.
Heat balance calculations around the regenerator of FCC units show that increasing the heat capacity of the respective FCC catalyst will reduce the temperature of the catalyst or contact material in the regenerator.
While old prior art such as U.S. Patent 2,400,176, E.W.
Thiele, (1946) and U.S. Patent 2,462,891, H. D. Noll, (1949) refer to incorporation of heat retention materials into FCC catalysts, they fail to suggest the use of materials having heat capacities substantially in excess of 0.27 BTU/lb.F nor do they suggest the use of high heat capacity materials which have been encapsulated to protect zeolite used therewith from premature deactivation. Further, this invention is particularly suitable for use with high zeolite content catalysts such as those described in U.S. Patent 4,493,902 but the prior art reference-~ fail to suggest that the benefits obtained by incorporating "heat retention materials" would be greater for high zeolite content catalysts. Therefore, this invention relates to novel FCC catalysts having effective heat capacities greater than conventional FCC catalysts (i.e. about 0.27 BTU/lb.F). This invention also relates to a specific method of manufacturing such a catalyst by combining high activity cracking component microspheres with separate microspheres containing a high heat capacity component such as 2MgO-B~O~.
For the purpose of this invention, effective heat capacity (Cpe) of a catalyst is defined as follows:
effective catalyst H
heat capacity (Cpe) Regen. Temp. - React. Temp.
where H is the enthalpy change of the catalyst between reactor and regenerator temperatures This invention, in its broadest sense, concerns novel FCC
catalysts having heat capacities greater than conventional FCC cataly~ts, and the use of such catalysts in FCC units such that they lower the regenerator temperature. Prlor art suggested the use of inert high heat capacity materials for heat retention in FCC
processes, but the accompanying disclosure indicates that they could not have achieved the results of the present invention because the disclosed materials did not have heat capacities substantially above that of conventional FCC catalysts. For example, the Thiele patent suggested the use of iron or quartz. Iron has a heat capacity 30g lower than FCC catalysts, and quartz has a comparable heat capacity to conventional FCC catalysts.
~.z89~i~
The present invention also provides for the preparation and use of high heat capacity catalysts (effective heat capacity greater than 0.29 BTU/lb.F) to reduce the regenerator temperature of FCC units. Two ways to achieve this include:
1. Produce FCC catalysts containing substantial amount of elements having an atomic number of from 3 to 12, e.g. compounds containing carbon, lithium, beryllium, boron, magnesium, etc.
EFFECTIVE HEAT CAPACITY
Fluid catalytic cracking is central to modern petroleum refineries. Zeolite containing cracking catalysts efficiently convert less valuable long chain hydrocarbons to more valuable shorter molecules. In many cases, the production of an entire refinery complex is controlled by its Fluid Catalytic Cracking (FCC) unit.
In many cases, especially in older systems, it would be desirable to obtain higher temperatures within the reactor by some means such as increasing the feed pre-heat temperature as this would normally lead to increased conversion, cracked products of higher octane, and the ability to use lower quality feedstocks, but an increase in reactor temperatures would lead to an unacceptable temperature within the regenerator. Thus, the production of the FCC unit and in turn, the refinery, is often limited by the maximum temperature that the construction of the re~enerator can tolerate. Therefore, it is desirable to obtain methods of increasing the FCC
reactor temperature without unduly increasing regenerator temperature.
The method and catalyst compositions of the present $nvention provide for catalytic cracking with improved yields at a constant regenerator temperature and may be used with any conventional zeolitic cracking catalyst but is exceptionally well suited for use with high zeolite catalysts such as those disclosed in U.S.P. 4,493,902.
la Various aspects of this invention are as follows:
A catalytic composition for use in fluid catalytic cracking comprising a zeolite FCC catalyst and a component of higher heat retentiveness in the form of fluidizable particles consisting essentially of inert compounds such that the composition has a heat capacity of at least 1214 J/KgK (0.29 BTU/lb.~F) over the range from 510-705C (950-1300F).
A method of fluidized catalytic cracking using a catalytic composition referred to in the previous paragraph.
According to the present invention, regenerator temperature iB controlled by incorporating a heat reten-tion component into the catalyst composition. The high heat capacity component may either be incorporated into the matrix of the zeolite containing particles or it may be present as separate particles circulating with the .~, I
95~3 zeolite containing particles. In many circumstances, it is advantageous to incorporate the heat capacity in-creasing component both into the matrix of the zeolite containing particles as well as to include separate particles with high heat capacity. There are two primary requirements for the high heat capacity component: it must not destroy zeolite too rapidly, and its effective heat capacity must be in excess of 0.29 BTU/lb.F in the temperature range between the reactor temperature of about 950F and the regenerator temperature of about 1300F. In many cases, it will be advantageous to use a material which upon heating undergoes an endothermic reversible phase change between the reactor temperature and the regenerator temperature. Further, many materials which tend to destroy zeolite too rapidly may be incor-porated into non-zeolite containing particles in the catalytic composition by coating the material with an inert material which prevents or delays the interaction between the zeolite and the heat retention material.
Similarly, zeolite deactivating materials may be incor-porated into the matrix of zeolite containing particles if suitable passivating components are also included.
The preferred heat retention components are fluidizable particles consisting essentially of inert compounds, such as the oxides of lithium, beryllium, boron and magnesium as well as carbon containing compounds of these. The most preferred heat retention composition is dimagnesium borate (2MgO B~03) containing an excess of MgO over the 54 weight % stoichiometric value to ensure that B,03 is immobilized to alleviate interaction with zeolite. This composition is quite inert with respect to zeolite.
Another suitable relatively inert compound is boron carbide (B4C). Other suitable but less inert composi-tions include lithium magnesium borate (Li20 MgO B203), including MgO in excess of 55 weight % stoichiometric value, lithium aluminates (Li20 Al203), including lZ895~3 aluminum oxide in excess of the 80 weight %
stoichiometric value, magnesium borate ~MgO B2O3) containing MgO in less than 54 weight %
stoichiometric value and lithium aluminum silicates (Li2O Al~03 SiO2) containing lithium oxide in less than the 20 weight % stoichiometric value. Other suitable compounds which should normally be encapsulated or otherwise passivated include lithium aluminum borate (2Li,O Al2O3 Bz03), lithium magnesium borates including either boron oxide in excess of the 30 weight %
stoichiometric value or lithium oxide in excess of the 15 weight % stoichiometric value, lithium aluminates (Li~o Al~03) containing lithium oxide in excess of the 20 weight % stoichiometric value, lithium aluminum silicates including lithium oxide in excess of the 20 weight %
stoichiometric value and boron phosphate (B2O3 P,O5).
While these materials can be used to provide increased heat capacity, it will normally be prudent to encapsulate them with a more inert material such as magnesia or alumina to protect the zeolite from premature deactivation due to interaction with the heat retention component. The preferred zeolite for incorporation in the compositions of the present invention is zeolite-Y, i.e. faujasite.
Heat balance calculations around the regenerator of FCC units show that increasing the heat capacity of the respective FCC catalyst will reduce the temperature of the catalyst or contact material in the regenerator.
While old prior art such as U.S. Patent 2,400,176, E.W.
Thiele, (1946) and U.S. Patent 2,462,891, H. D. Noll, (1949) refer to incorporation of heat retention materials into FCC catalysts, they fail to suggest the use of materials having heat capacities substantially in excess of 0.27 BTU/lb.F nor do they suggest the use of high heat capacity materials which have been encapsulated to protect zeolite used therewith from premature deactivation. Further, this invention is particularly suitable for use with high zeolite content catalysts such as those described in U.S. Patent 4,493,902 but the prior art reference-~ fail to suggest that the benefits obtained by incorporating "heat retention materials" would be greater for high zeolite content catalysts. Therefore, this invention relates to novel FCC catalysts having effective heat capacities greater than conventional FCC catalysts (i.e. about 0.27 BTU/lb.F). This invention also relates to a specific method of manufacturing such a catalyst by combining high activity cracking component microspheres with separate microspheres containing a high heat capacity component such as 2MgO-B~O~.
For the purpose of this invention, effective heat capacity (Cpe) of a catalyst is defined as follows:
effective catalyst H
heat capacity (Cpe) Regen. Temp. - React. Temp.
where H is the enthalpy change of the catalyst between reactor and regenerator temperatures This invention, in its broadest sense, concerns novel FCC
catalysts having heat capacities greater than conventional FCC cataly~ts, and the use of such catalysts in FCC units such that they lower the regenerator temperature. Prlor art suggested the use of inert high heat capacity materials for heat retention in FCC
processes, but the accompanying disclosure indicates that they could not have achieved the results of the present invention because the disclosed materials did not have heat capacities substantially above that of conventional FCC catalysts. For example, the Thiele patent suggested the use of iron or quartz. Iron has a heat capacity 30g lower than FCC catalysts, and quartz has a comparable heat capacity to conventional FCC catalysts.
~.z89~i~
The present invention also provides for the preparation and use of high heat capacity catalysts (effective heat capacity greater than 0.29 BTU/lb.F) to reduce the regenerator temperature of FCC units. Two ways to achieve this include:
1. Produce FCC catalysts containing substantial amount of elements having an atomic number of from 3 to 12, e.g. compounds containing carbon, lithium, beryllium, boron, magnesium, etc.
2. Produce FCC catalysts which undergo a reversible endothermic transformation upon heating from conventional FCC stripping temperature (about 1000F) to regeneratsr temperatures (above 1100F) such that there is a corresponding exothermic transformation upon cooling from the regenerator temperature to the cracking reactor temperature (from above 1100 to 1000F).
Prior art relevant to this invention is disclosed in patents issued to Standard Oil Company (U.S. Patent 2,400,176) and Houdry Process Corporation (U.S. Patent 2,462,891). In both cases, the use of an inert material with high heat capacity for heat retention was proposed.
However, the inventors did not anticipate the concept of the present invention, since the heat capacity of the materials claimed in their invention was less than or comparable to conventional FCC catalysts. The fact that these materials do not have a higher heat capacity than silica/alumina indicates that they are not suitable to reduce the regenerator temperature of FCC units.
This invention provides a novel composition of matter for FCC catalysts, i.e. one having an effective heat capacity of at least about 0.29 BTU/lb.F. The process of using this catalyst in FCC units to crack hydrocarbons is also included. For example, two ways to achieve effective heat capacity greater than 0.27 BTU/lb.F are:
1289~43 1. Produce FCC catalysts containing large amounts of elements having an atomic number of from 3 to 12, e.g.
compounds containing carbon, lithium, beryllium, boron, magnesium, and the like either incorporated into the matrix of the zeolite containing particles or incorporated as fluidizable particles physically mixed and circulated with the zeolite containing particles.
2. Produce FCC catalysts materials which undergo a reversible endothermic transformation upon heating from conventional FCC stripping temperature (about 1000F) to regenerator temperatures (above 1100 F) such that there is a corresponding exothermic transformation upon cooling from the regenerator temperature to the cracking reactor temperature (from above 1100 to 1000 F).
Use of the catalytic compositions of the present invention makes it possible to burn more coke in the regenerator, obtain increased conversion, use a greater throughput of residual fractions and use feeds containing larger amounts of basic nitrogen compounds. The above described catalytic materials can be prepared, for example, by spray drying a high heat capacity component with a zeolite-Y containing component such as pure zeolite-Y. Another method of preparing this material is by blending separate fluidizable particles of a high heat capacity component with a zeolite-Y containing component.
Small amounts of ZSM-5 zeolite (e.g. 1-5~) may be included in the catalytic microspheres if desired.
Based on heat balance calculations, a catalyst with high heat capacity is useful for reduction of regenerator temperatures. The measured heat capacity of conventional equilibrium FCC catalysts is 0.27 BTU/lb.F. For example, a catalyst with a heat capacity of 0.29 BTU/lb.F will provide approximately 20F reduction of regenerator temperature, while a catalyst with a heat capacity of 0.32 BTU/lb.F will produce a 50F reduction in regenerator temperature.
-- 12895~3 Throughout this specification (unless otherwise stated) all heat capacities are as determined using a Setaram 111 Differential Scanning Calorimeter ~DSC) calibrated to indicate a value of 0.28 BTU/lb.F for the heat capacity of syntheTtMic sapphire at 500C.
Alternatively, a DuPont 910 Differential Scanning Calorimeter ~DSC) can be used but the Setaram 111 seems to provide the most consistent and meaningful results in the range of 1000 to 1300F.
ExamPle I
The following example describes the preparation and use of a preferred high heat capacity material:
2MgO B,O, The 2MgO ~O~ sample was prepared by slurrying a mixture containing a 1:1 mole ratio of Mg(OH)~ and H3~03 in water, milling, extruding, drying, and then calcining at 1800F for one hour. The resulting solid was ground and washed twice with 20g of water per gram of solid at a temperature of 90C for 0.5 to 1 hour to remove any unreacted B~O3 present in the product. Wet chemical analysis indicated a magnesia contont of 55 weight ~ and a boron oxld- contont of 45 woight ~.
The measured h-at capacity of this 2MgO B,O, sample i8 O. 37 BTU/lb.F at 700C (1292F). Based on a measured heat capacity of 0.27 BTU/lb.F for an equilibrium FCC
catalyst, the use of thi~ inert additive at 50 weight 3 provided a catalyst with a heat capacity of 0.32 BTU/lb.F heat capacity. Heat capacity measurements were made using two calorimetors, tho DuPont 910 Dlfferential Scanning Calorimeter and the Setaram 111 Differential Scanning Calorimeter. The DuPont system is capable of heat capacity measurements up to 700C, while the Setaram system can bo used up to 810C. At temperatures above 500C, the Seteram DSC provides more meaningful heat capacity data than the DuPont system. Heat capacity data were obtained using a reference heat capacity of 0.27 12~39543 BTU/lb.F at 500C for Engelhard equilibrium catalysts such as Ultrasiv R 260, Magnasiv R 380 and HEZ-55 , and 0.28 BTU/lb.F at 500C for synthetic sapphire. Unless otherwise stated, all heat capacity measurements are to be understood to be as measured on the Setaram 111 calibrated to indicate a heat capacity of 0.28 BTU/lb.F
at 500C for synthetic sapphire throughout this specification. Heat balance calculations demonstrate that a catalyst with an 0.32 BTU/lb.F heat capacity, when used in the place of a conventional FCC catalyst, can reduce regenerator temperatures by about 50F.
The material prepared above was steamed as a blend with microspheres containing a high zeolite-Y content catalyst (prepared as described in Example 1 of U.S.P.
4,493,902, except that only a single rare earth exchange [to a rare earth oxide content of 8%] was carried out after the initial ammonium exchange) in a 1:1 weight ratio. The temperatures used were 1350 and 1450F, using 100% steam at 1 atmosphere for four hours. MAT testing results of the steamed samples are provided below:
Steaming Temperature 1350F 1450F
Conversion (%) 87 82 The same conversions were obtained for samples which contained 2MgO B~O, and the high zeolite content catalyst which were steamed individually and then combined for MAT
testing. These data indicate that no deactivation of zeolite-Y occurred during steaming.
When the same 1:1 blend described above was steamed at 1500F for 4 hours using 100% steam, a 59% conversion was obtained. Since a 76% conversion was obtained using the control sample, these data indicated some deactivation had occurred at the higher steaming temperature. However, better activity retention can be obtained (conversion = 66%), if the dimagnesium borate sample is calcined at 1850F for 4 hours prior to steaming and MAT testing with the zeolite-Y component.
~2895~
g However, activity loss in this test can be substantially eliminated if the dimagnesium borate is calcined at 1800F for 8 hours then washed twice as above. When the above test procedure was repeated using catalytic compositions containing dimagnesium borate which had been cleansed of active boron compounds in this fashion, a conversion at 76% was obtained after steaming.
Example II
The following example describes a high heat capacity material which deactivates zeolite-Y and thus should be encapsulated with an inert material for use in this invention.
A MgO 2B2O3 sample was prepared by combining a 1:4 mole ratio of Mg(OH)~ and H3BO3 in water. ~his mixture was milled, extruded, dried and then calcined at 1400F
for one hour. The resulting solid was ground and washed twice with water. The dried solid obtained has a heat capacity of 0.35 BTU/lb.F at 500C (932F) using the DuPont DSC. This material was blended with a high zeolite-Y component as described in Example I in a 1:1 weight ratio and then steamed at 1450F using 100% steam for four hours. MAT testing results showed 6-10%
conversion for this sample, which indicated that extensive zeolite deactivation had occurred during steaming. These data indicate that this magnesia deficient system is less suitable for use as a high heat capacity catalyst.
Prior art relevant to this invention is disclosed in patents issued to Standard Oil Company (U.S. Patent 2,400,176) and Houdry Process Corporation (U.S. Patent 2,462,891). In both cases, the use of an inert material with high heat capacity for heat retention was proposed.
However, the inventors did not anticipate the concept of the present invention, since the heat capacity of the materials claimed in their invention was less than or comparable to conventional FCC catalysts. The fact that these materials do not have a higher heat capacity than silica/alumina indicates that they are not suitable to reduce the regenerator temperature of FCC units.
This invention provides a novel composition of matter for FCC catalysts, i.e. one having an effective heat capacity of at least about 0.29 BTU/lb.F. The process of using this catalyst in FCC units to crack hydrocarbons is also included. For example, two ways to achieve effective heat capacity greater than 0.27 BTU/lb.F are:
1289~43 1. Produce FCC catalysts containing large amounts of elements having an atomic number of from 3 to 12, e.g.
compounds containing carbon, lithium, beryllium, boron, magnesium, and the like either incorporated into the matrix of the zeolite containing particles or incorporated as fluidizable particles physically mixed and circulated with the zeolite containing particles.
2. Produce FCC catalysts materials which undergo a reversible endothermic transformation upon heating from conventional FCC stripping temperature (about 1000F) to regenerator temperatures (above 1100 F) such that there is a corresponding exothermic transformation upon cooling from the regenerator temperature to the cracking reactor temperature (from above 1100 to 1000 F).
Use of the catalytic compositions of the present invention makes it possible to burn more coke in the regenerator, obtain increased conversion, use a greater throughput of residual fractions and use feeds containing larger amounts of basic nitrogen compounds. The above described catalytic materials can be prepared, for example, by spray drying a high heat capacity component with a zeolite-Y containing component such as pure zeolite-Y. Another method of preparing this material is by blending separate fluidizable particles of a high heat capacity component with a zeolite-Y containing component.
Small amounts of ZSM-5 zeolite (e.g. 1-5~) may be included in the catalytic microspheres if desired.
Based on heat balance calculations, a catalyst with high heat capacity is useful for reduction of regenerator temperatures. The measured heat capacity of conventional equilibrium FCC catalysts is 0.27 BTU/lb.F. For example, a catalyst with a heat capacity of 0.29 BTU/lb.F will provide approximately 20F reduction of regenerator temperature, while a catalyst with a heat capacity of 0.32 BTU/lb.F will produce a 50F reduction in regenerator temperature.
-- 12895~3 Throughout this specification (unless otherwise stated) all heat capacities are as determined using a Setaram 111 Differential Scanning Calorimeter ~DSC) calibrated to indicate a value of 0.28 BTU/lb.F for the heat capacity of syntheTtMic sapphire at 500C.
Alternatively, a DuPont 910 Differential Scanning Calorimeter ~DSC) can be used but the Setaram 111 seems to provide the most consistent and meaningful results in the range of 1000 to 1300F.
ExamPle I
The following example describes the preparation and use of a preferred high heat capacity material:
2MgO B,O, The 2MgO ~O~ sample was prepared by slurrying a mixture containing a 1:1 mole ratio of Mg(OH)~ and H3~03 in water, milling, extruding, drying, and then calcining at 1800F for one hour. The resulting solid was ground and washed twice with 20g of water per gram of solid at a temperature of 90C for 0.5 to 1 hour to remove any unreacted B~O3 present in the product. Wet chemical analysis indicated a magnesia contont of 55 weight ~ and a boron oxld- contont of 45 woight ~.
The measured h-at capacity of this 2MgO B,O, sample i8 O. 37 BTU/lb.F at 700C (1292F). Based on a measured heat capacity of 0.27 BTU/lb.F for an equilibrium FCC
catalyst, the use of thi~ inert additive at 50 weight 3 provided a catalyst with a heat capacity of 0.32 BTU/lb.F heat capacity. Heat capacity measurements were made using two calorimetors, tho DuPont 910 Dlfferential Scanning Calorimeter and the Setaram 111 Differential Scanning Calorimeter. The DuPont system is capable of heat capacity measurements up to 700C, while the Setaram system can bo used up to 810C. At temperatures above 500C, the Seteram DSC provides more meaningful heat capacity data than the DuPont system. Heat capacity data were obtained using a reference heat capacity of 0.27 12~39543 BTU/lb.F at 500C for Engelhard equilibrium catalysts such as Ultrasiv R 260, Magnasiv R 380 and HEZ-55 , and 0.28 BTU/lb.F at 500C for synthetic sapphire. Unless otherwise stated, all heat capacity measurements are to be understood to be as measured on the Setaram 111 calibrated to indicate a heat capacity of 0.28 BTU/lb.F
at 500C for synthetic sapphire throughout this specification. Heat balance calculations demonstrate that a catalyst with an 0.32 BTU/lb.F heat capacity, when used in the place of a conventional FCC catalyst, can reduce regenerator temperatures by about 50F.
The material prepared above was steamed as a blend with microspheres containing a high zeolite-Y content catalyst (prepared as described in Example 1 of U.S.P.
4,493,902, except that only a single rare earth exchange [to a rare earth oxide content of 8%] was carried out after the initial ammonium exchange) in a 1:1 weight ratio. The temperatures used were 1350 and 1450F, using 100% steam at 1 atmosphere for four hours. MAT testing results of the steamed samples are provided below:
Steaming Temperature 1350F 1450F
Conversion (%) 87 82 The same conversions were obtained for samples which contained 2MgO B~O, and the high zeolite content catalyst which were steamed individually and then combined for MAT
testing. These data indicate that no deactivation of zeolite-Y occurred during steaming.
When the same 1:1 blend described above was steamed at 1500F for 4 hours using 100% steam, a 59% conversion was obtained. Since a 76% conversion was obtained using the control sample, these data indicated some deactivation had occurred at the higher steaming temperature. However, better activity retention can be obtained (conversion = 66%), if the dimagnesium borate sample is calcined at 1850F for 4 hours prior to steaming and MAT testing with the zeolite-Y component.
~2895~
g However, activity loss in this test can be substantially eliminated if the dimagnesium borate is calcined at 1800F for 8 hours then washed twice as above. When the above test procedure was repeated using catalytic compositions containing dimagnesium borate which had been cleansed of active boron compounds in this fashion, a conversion at 76% was obtained after steaming.
Example II
The following example describes a high heat capacity material which deactivates zeolite-Y and thus should be encapsulated with an inert material for use in this invention.
A MgO 2B2O3 sample was prepared by combining a 1:4 mole ratio of Mg(OH)~ and H3BO3 in water. ~his mixture was milled, extruded, dried and then calcined at 1400F
for one hour. The resulting solid was ground and washed twice with water. The dried solid obtained has a heat capacity of 0.35 BTU/lb.F at 500C (932F) using the DuPont DSC. This material was blended with a high zeolite-Y component as described in Example I in a 1:1 weight ratio and then steamed at 1450F using 100% steam for four hours. MAT testing results showed 6-10%
conversion for this sample, which indicated that extensive zeolite deactivation had occurred during steaming. These data indicate that this magnesia deficient system is less suitable for use as a high heat capacity catalyst.
Claims (10)
1. A catalytic composition for use in fluid catalytic cracking comprising a zeolite FCC catalyst and a component of higher heat retentiveness in the form of fluidizable particles consisting essentially of inert compounds such that the composition has a heat capacity of at least 1214 J/Kg °K (0.29 BTU/lb.°F) over the range from 510-705°C (950-1300°F).
2. A catalytic composition according to claim 1 comprising microspheres containing in situ crystallized Y-faujasite and, as the component of higher heat retentiveness, fluidizable particles consisting primarily of dimagnesium borate, the weight of the microspheres containing Y-faujasite being from about 15 to about 80% of the weight of the total catalytic composition.
3. A catalytic composition according to claim 1 including a component of higher heat retentiveness selected from dimagnesium borate, boron carbide, alumina stabilized dimagnesium borate containing from about 2 to about 10% alumina, aluminium borate, magnesium tetraborate, magnesium orthoborate, lithium aluminium borate, lithium magnesium borate, lithium aluminium silicate, and lithium aluminate.
4. A catalytic composition according to claim 1 containing lithium aluminate as a component of higher heat retentiveness.
5. A catalytic composition according to claim 1 comprising microspheres containing Y-faujasite and alumina stabilized dimagnesium borate containing from about 2 to about 10% alumina.
6. A catalytic composition according to claim 1 comprising microspheres containing Y-faujasite and microspheres comprising a core of higher heat retentiveness material selected from dimagnesium borate, magnesium tetraborate, magnesium orthoborate, lithium aluminium borate, lithium magnesium borate, and lithium aluminate, said core being encapsulated with inert material chosen from magnesia, alumina and alumina stabilized dimagnesium borate containing from about 2 to about 10% alumina.
7. A catalytic composition according to claim 1 including microspheres containing crystallized Y-faujasite, alumina stabilized dimagnesium borate containing from about 2 to about 10% alumina, and a minor proportion of ZSM-5 zeolite, said microspheres containing at least about 20% by weight Y-faujasite, at least about 10% by weight dimagnesium borate, at least 1% by weight ZSM-5 zeolite, and the balance essentially silica-alumina matrix.
8. A catalytic composition according to claim 1 including microspheres containing crystallized Y-faujasite, alumina stabilized dimagnesium borate containing from about 3% to about 10% alumina and a minor proportion of ZSM-5 zeolite.
9. A method of fluidized catalytic cracking using a catalytic composition according to any one of claims 1 to 8.
10. A method according to claim 9 comprising the steps of contacting a petroleum fraction with the catalytic composition, separating the catalytic composition from the fraction and regenerating the catalytic composition by contact with oxygen containing gas at elevated temperature.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US77133485A | 1985-08-30 | 1985-08-30 | |
| US771,334 | 1985-08-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1289543C true CA1289543C (en) | 1991-09-24 |
Family
ID=25091479
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000517224A Expired - Lifetime CA1289543C (en) | 1985-08-30 | 1986-08-29 | Fcc catalysts of increased effective heat capacity |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS62110750A (en) |
| CA (1) | CA1289543C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9441167B2 (en) * | 2013-12-19 | 2016-09-13 | Basf Corporation | Boron oxide in FCC processes |
-
1986
- 1986-08-29 CA CA000517224A patent/CA1289543C/en not_active Expired - Lifetime
- 1986-08-30 JP JP20501986A patent/JPS62110750A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62110750A (en) | 1987-05-21 |
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