CN107955639B - Method for cracking hexaalkane - Google Patents

Method for cracking hexaalkane Download PDF

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CN107955639B
CN107955639B CN201610898329.3A CN201610898329A CN107955639B CN 107955639 B CN107955639 B CN 107955639B CN 201610898329 A CN201610898329 A CN 201610898329A CN 107955639 B CN107955639 B CN 107955639B
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zsm
molecular sieve
hexaalkane
cracking
hours
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CN107955639A (en
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黄政
金国杰
高焕新
杨洪云
刘远林
汪超
丁琳
康陈军
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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Sinopec Shanghai Research Institute of Petrochemical Technology
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G11/02—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils characterised by the catalyst used
    • C10G11/04—Oxides
    • C10G11/05—Crystalline alumino-silicates, e.g. molecular sieves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/80—Mixtures of different zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/18—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the mordenite type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/7034—MTW-type, e.g. ZSM-12, NU-13, TPZ-12 or Theta-3
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
    • C10G2300/10—Feedstock materials
    • C10G2300/1081—Alkanes

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Materials Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Catalysts (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention relates to a method for cracking hexaalkane, which mainly solves the technical problems of low catalytic activity and poor stability in the prior art. The invention adopts ZSM-12(MTW) and Mordenite (MOR) symbiotic composite material as catalyst, and the catalytic reaction conditions are as follows: the method comprises the following steps of taking hexaalkane as a raw material, enabling the reaction temperature to be 270-550 ℃, enabling the reaction pressure to be 0.01-1 MPa, and enabling the raw material to be in contact reaction with an eutectic molecular sieve catalyst. The catalyst comprises the following components in parts by weight: a) 30-100 parts of mercerized/ZSM-12 intergrowth composite molecular sieve material with the Si/Al molar ratio less than 100, wherein the weight ratio of the ZSM-12 molecular sieve is 10-50%; b) 0-70 parts of binder, and the technical scheme can be used for better solving the problem and can be used for industrial production of low-carbon olefin.

Description

Method for cracking hexaalkane
Technical Field
The invention relates to a method for cracking hexaalkane.
Background
The petrochemical industry has developed into one of the key prop industries for promoting economic development of various countries nowadays, and the key raw materials of the petrochemical industry and the petrochemical industry, namely low-carbon olefin: the yield of ethylene and propylene becomes a weather meter of the national petrochemical and economic development level. In the petroleum refining industry, processes such as catalytic cracking have commercialized the primary route for the synthesis of lower olefins from hydrocarbonaceous materials.
Since the beginning of the 20 th century in the 60's, molecular sieves have been used as catalytic cracking catalysts and have been widely used in catalytic cracking reactions due to their high thermal stability, catalytic activity and selectivity. Commonly used zeolite molecular sieves with a single structure such as A type, X type, Y type, M type and ZSM type. With the continuous improvement of the quality requirements of chemical products, higher requirements are also put forward on the catalytic performance of the zeolite molecular sieve.
CN102373069A discloses a method for cracking carbon hexaalkane, which adopts ZSM-5 and mordenite symbiotic composite material as catalyst, however, ZSM-5 is MFI and is formed by ten-membered ring, and mordenite is MOR and is formed by twelve-membered ring, therefore, ZSM-5/MOR has a composite structure which is not stable between the ten-membered ring and the twelve-membered ring, which causes the problems of low activity and poor stability when used in the cracking reaction of carbon hexaalkane.
Disclosure of Invention
The invention relates to a method for cracking hexaalkane, which mainly solves the technical problems of low catalytic activity and poor stability of the hexaalkane cracking reaction in the prior art. The invention provides a method for cracking hexaalkane, which adopts mercerization/ZSM-12 intergrowth composite molecular sieve as a catalyst, and the mercerization/ZSM-12 composite molecular sieve has better stability and catalytic activity.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a method for cracking carbon hexaalkane takes the carbon hexaalkane as a raw material, the raw material and a catalyst are contacted to react to generate C1-C5 hydrocarbon, wherein the used catalyst comprises the following components in parts by weight:
a) 30-100 parts of mercerized/ZSM-12 intergrowth composite molecular sieve with the Si/Al molar ratio of 10-100; wherein the weight proportion of the ZSM-12 molecular sieve is 10-50%;
b) 0-70 parts of a binder.
In the above technical solution, preferably, the carbon hexaalkane includes at least one selected from n-hexane, 3-methylpentane and 2-methylpentane; more preferably, n-hexane to 3-methylpentane in a ratio of 1: 1.
in the technical scheme, the preferable range of the reaction temperature is 250-600 ℃, and the more preferable range is 270-500 ℃. The reaction pressure is preferably in the range of 0.1 to 1MPa, more preferably in the range of 0.1 to E0.5 MPa. The preferable range of the liquid phase space velocity is 0.01-3 hours-1More preferably in the range of 0.1 to 1 hour-1。
In the technical scheme, the mercerization/ZSM-12 molecular sieve is used in an amount of 40-90 parts by weight, preferably, the binderless mercerization/ZSM-12 symbiotic composite molecular sieve without the binder is adopted, and the mechanical strength of the molecular sieve can reach 40 newtons.
In the technical scheme, the binder is selected from alumina or silica.
In the above technical scheme, preferably, the mercerization/ZSM-12 intergrowth composite molecular sieve has a silica-alumina molar ratio Si/Al of 20 to 80.
In the technical scheme, the weight proportion of the ZSM-12 of the mercerized/ZSM-12 symbiotic composite zeolite is 15-40%.
The preparation method of the mercerization/ZSM-12 intergrowth composite molecular sieve comprises the following steps: firstly, a silicon source, an aluminum source, a template agent R and water form a mixture, and the molar ratio of the mixture is as follows: 37.5-50% of Si/Al; h2O/SiO2＝15～30；R/SiO20.1 to 0.5; and adding an alkali source into the mixture of tetraethylammonium hydroxide and tetraethylammonium chloride as a template agent R to form a synthetic reaction system of ZSM-12, adding mordenite, continuously stirring until the mixture is uniform, crystallizing at the temperature of 120-200 ℃ for 20-120 hours to obtain a crystallized product, and washing and drying the crystallized product to obtain the mercerization/ZSM-12 intergrowth composite molecular sieve. The alkali source can be sodium hydroxide, ammonia water and the like.
The preparation method of the catalyst comprises the following steps: firstly, mixing the synthesized MOR/MTW intergrowth composite molecular sieve and activated alumina, adding a binder to carry out mixing kneading, molding, drying and roasting to prepare a catalyst precursor, then exchanging sodium ions in the catalyst precursor by using an ammonium salt solution, and finally carrying out drying, roasting and activating to obtain a catalyst finished product.
The invention adopts a mercerization/ZSM-12 intergrowth composite molecular sieve catalyst, wherein ZSM-12 is MTW and is formed by twelve-membered rings, mordenite is MOR and is formed by twelve-membered rings, and the mercerization/ZSM-12 has a stable composite structure of the twelve-membered rings, and the possible interaction of the two structures is utilized to simultaneously regulate and control the silicon-aluminum ratio of the mercerization/ZSM-12 intergrowth composite molecular sieve catalyst and the weight ratio of MOR and MTW in the mercerization/ZSM-12 intergrowth composite molecular sieve catalyst, so that the catalytic activity of the reaction is at least 10 percent higher than that of mechanical mixing, and meanwhile, the reaction evaluation is basically unchanged within 400 hours, the stability is good, and better technical effects are obtained.
The invention is further illustrated by the following examples.
Detailed Description
Example 1:
the preparation method of the mercerization/ZSM-12 molecular sieve comprises the following steps:
in the first step, 35.22 g of water glass, 1.1 g of sodium hydroxide and 6.45 g of solid aluminum sulfate are mixed with 141 g of distilled water, and then ammonia (containing NH) is added325.5 wt%) of 10 g, uniformly mixing, placing into a reaction kettle, crystallizing at 180 ℃ for 48 hours, cooling to room temperature after crystallization is finished, filtering and washing, and then placing into an oven to dry at 100 ℃ for 3-4 hours to obtain mordenite raw powder.
And secondly, taking 25.6g of silica sol (wt 40%), 0.25g of sodium metaaluminate, 1g of sodium hydroxide, 40g of deionized water, 9.5g of 30 wt% tetraethylammonium bromide, 3.9g of 30 wt% tetraethylammonium hydroxide and 3.25g of 30 wt% tetraethylammonium chloride, mixing, and stirring uniformly at room temperature. The pH was adjusted to 13 with 10% aqueous sodium hydroxide solution and left to stand for 6 hours. Then adding 9g of mordenite seed crystal synthesized in the first step, fully stirring, then placing into a reaction kettle, crystallizing for 72 hours at 160 ℃, and drying for 3-4 hours in an oven at 100 ℃ to obtain the symbiotic composite molecular sieve raw powder. Then crystallized at 180 ℃ for 72 hours. The resulting milky white slurry was washed 5 times with deionized water and then dried under vacuum for 12 hours. Obtaining the intergrowth composite molecular sieve raw powder.
36 g of synthesized mixed crystal molecular sieve and 24 g of alumina are mixed, and the mixed powder and dilute nitric acid (0.5 weight percent) are mixed according to the weight ratio of 80: 20 by weight ratio, kneading, molding and drying. Roasting the catalyst precursor for 6 hours at 550 ℃ in air to obtain the catalyst precursor.
The catalyst precursor thus obtained was ion-exchanged 3 times with a 10% by weight ammonium nitrate solution, each time at 90 ℃ for 3 hours, with a sodium content of less than 50ppm after the treatment. And filtering and drying the catalyst precursor subjected to ammonium exchange at room temperature, activating for 4 hours at the temperature of 550 ℃ in the air, and cooling to room temperature to obtain the catalyst.
1g of 60 percent mercerized/ZSM-12 molecular sieve catalyst (the Si/Al molar ratio is 20) (the MTW weight ratio is 30 percent) and 40 percent of alumina binder are added into a 10 ml fixed bed reactor, the particle size is 20-40 meshes, and the molar ratio of the reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.5h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 280 ℃ under normal pressure, the product was analyzed by on-line gas chromatography. The n-hexane conversion was 45.43% and the 3-methylpentane conversion was 6.35%, and no reduction in conversion was observed at 400 hours of the reaction evaluation.
Example 2:
the preparation method of the mercerization/ZSM-12 molecular sieve comprises the following steps:
in the first step, 35.22 g of water glass, 1.1 g of sodium hydroxide and 6.45 g of solid aluminum sulfate are mixed with 141 g of distilled water, and then ammonia (containing NH) is added325.5 wt%) of 10 g, uniformly mixing, placing into a reaction kettle, crystallizing at 180 ℃ for 48 hours, cooling to room temperature after crystallization is finished, filtering and washing, and then placing into an oven to dry at 100 ℃ for 3-4 hours to obtain mordenite raw powder.
And secondly, taking 25.6g of silica sol (wt 40%), 0.25g of sodium metaaluminate, 1g of sodium hydroxide, 40g of deionized water, 9.5g of 30 wt% tetraethylammonium bromide, 3.9g of 30 wt% tetraethylammonium hydroxide and 3.25g of 30 wt% tetraethylammonium chloride, mixing, and stirring uniformly at room temperature. The pH was adjusted to 13 with 10% aqueous sodium hydroxide solution and left to stand for 6 hours. Then adding 12 g of mordenite seed crystal synthesized in the first step, fully stirring, then placing into a reaction kettle, crystallizing for 72 hours at 160 ℃, and drying for 3-4 hours in an oven at 100 ℃ to obtain the symbiotic composite molecular sieve raw powder. Then crystallized at 180 ℃ for 72 hours. The resulting milky white slurry was washed 5 times with deionized water and then dried under vacuum for 12 hours. Obtaining the intergrowth composite molecular sieve raw powder.
Mixing 24 g of synthesized mixed crystal molecular sieve with 36 g of alumina, mixing the mixed powder with dilute nitric acid (0.5 wt%) according to a ratio of 80: 20 by weight ratio, kneading, molding and drying. Roasting the catalyst precursor for 6 hours at 550 ℃ in air to obtain the catalyst precursor.
The catalyst precursor thus obtained was ion-exchanged 3 times with a 10% by weight ammonium nitrate solution, each time at 90 ℃ for 3 hours, with a sodium content of less than 50ppm after the treatment. And filtering and drying the catalyst precursor subjected to ammonium exchange at room temperature, activating for 4 hours at the temperature of 550 ℃ in the air, and cooling to room temperature to obtain the catalyst.
1g of 40 percent mercerized/ZSM-12 molecular sieve catalyst (the Si/Al molar ratio is 40) (the MTW weight ratio is 15 percent) and 60 percent of alumina binder are added into a 10 ml fixed bed reactor, the particle size is 20-40 meshes, and the molar ratio of the reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.5h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 300 ℃ under normal pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 62.77% and the conversion of 3-methylpentane was 9.80%. In the reaction evaluation, no decrease in the conversion rate was observed in 400 hours.
Example 3:
the preparation method of the mercerization/ZSM-12 molecular sieve comprises the following steps:
in the first step, 35.22 g of water glass, 1.1 g of sodium hydroxide and 6.45 g of solid aluminum sulfate are mixed with 141 g of distilled water, and then ammonia (containing NH) is added325.5 wt%) of 10 g, uniformly mixing, placing into a reaction kettle, crystallizing at 180 ℃ for 48 hours, cooling to room temperature after crystallization is finished, filtering and washing, and then placing into an oven to dry at 100 ℃ for 3-4 hours to obtain mordenite raw powder.
And secondly, taking 25.6g of silica sol (wt 40%), 0.25g of sodium metaaluminate, 1g of sodium hydroxide, 40g of deionized water, 9.5g of 30 wt% tetraethylammonium bromide, 3.9g of 30 wt% tetraethylammonium hydroxide and 3.25g of 30 wt% tetraethylammonium chloride, mixing, and stirring uniformly at room temperature. The pH was adjusted to 13 with 10% aqueous sodium hydroxide solution and left to stand for 6 hours. Then 8 g of mordenite seed crystal synthesized in the first step is added, the mixture is fully stirred and then is put into a reaction kettle, crystallized for 72 hours at 160 ℃, and dried for 3-4 hours in an oven at 100 ℃ to obtain the symbiotic composite molecular sieve raw powder. Then crystallized at 180 ℃ for 72 hours. The resulting milky white slurry was washed 5 times with deionized water and then dried under vacuum for 12 hours. Obtaining the intergrowth composite molecular sieve raw powder.
54 g of synthesized mixed crystal molecular sieve and 6g of alumina are mixed, and the mixed powder and dilute nitric acid (0.5 weight percent) are mixed according to the weight ratio of 80: 20 by weight ratio, kneading, molding and drying. Roasting the catalyst precursor for 6 hours at 550 ℃ in air to obtain the catalyst precursor.
The catalyst precursor thus obtained was ion-exchanged 3 times with a 10% by weight ammonium nitrate solution, each time at 90 ℃ for 3 hours, with a sodium content of less than 50ppm after the treatment. And filtering and drying the catalyst precursor subjected to ammonium exchange at room temperature, activating for 4 hours at the temperature of 550 ℃ in the air, and cooling to room temperature to obtain the catalyst.
1g of mercerized/ZSM-12 molecular sieve catalyst (the Si/Al molar ratio is 30) (the MTW weight ratio is 40%) with the content of 90% is added into a 10 ml fixed bed reactor, 10% is silicon oxide binder, the particle size is 20-40 meshes, and the molar ratio of the reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.5h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 350 ℃ under normal pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 48.07% and the conversion of 3-methylpentane was 19.64%. In the reaction evaluation, no decrease in the conversion rate was observed in 400 hours.
Example 4:
the preparation method of the mercerization/ZSM-12 molecular sieve comprises the following steps:
in the first step, 35.22 g of water glass, 1.1 g of sodium hydroxide and 6.45 g of solid aluminum sulfate are mixed with 141 g of distilled water, and then ammonia (containing NH) is added325.5 wt%) of 10 g, uniformly mixing, placing into a reaction kettle, crystallizing at 180 ℃ for 48 hours, cooling to room temperature after crystallization is finished, filtering and washing, and then placing into an oven to dry at 100 ℃ for 3-4 hours to obtain mordenite raw powder.
And secondly, taking 25.6g of silica sol (wt 40%), 0.25g of sodium metaaluminate, 1g of sodium hydroxide, 40g of deionized water, 9.5g of 30 wt% tetraethylammonium bromide, 3.9g of 30 wt% tetraethylammonium hydroxide and 3.25g of 30 wt% tetraethylammonium chloride, mixing, and stirring uniformly at room temperature. The pH was adjusted to 13 with 10% aqueous sodium hydroxide solution and left to stand for 6 hours. Then adding 12 g of mordenite seed crystal synthesized in the first step, fully stirring, then placing into a reaction kettle, crystallizing for 72 hours at 160 ℃, and drying for 3-4 hours in an oven at 100 ℃ to obtain the symbiotic composite molecular sieve raw powder. Then crystallized at 180 ℃ for 72 hours. The resulting milky white slurry was washed 5 times with deionized water and then dried under vacuum for 12 hours. Obtaining the intergrowth composite molecular sieve raw powder.
30 g of synthesized mixed crystal molecular sieve and 30 g of alumina are mixed, and the mixed powder and dilute nitric acid (0.5 weight percent) are mixed according to the weight ratio of 80: 20 by weight ratio, kneading, molding and drying. Roasting the catalyst precursor for 6 hours at 550 ℃ in air to obtain the catalyst precursor.
The catalyst precursor thus obtained was ion-exchanged 3 times with a 10% by weight ammonium nitrate solution, each time at 90 ℃ for 3 hours, with a sodium content of less than 50ppm after the treatment. And filtering and drying the catalyst precursor subjected to ammonium exchange at room temperature, activating for 4 hours at the temperature of 550 ℃ in the air, and cooling to room temperature to obtain the catalyst.
1g of 50 percent mercerized/ZSM-12 molecular sieve catalyst (the Si/Al molar ratio is 80) (the MTW weight ratio is 15 percent) and 50 percent of alumina binder are added into a 10 ml fixed bed reactor, the particle size is 20-40 meshes, and the molar ratio of the reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 1h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 400 ℃ under normal pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 95.33% and the conversion of 3-methylpentane was 35.23%. In the reaction evaluation, no decrease in the conversion rate was observed in 400 hours.
Example 5:
the preparation method of the mercerization/ZSM-12 molecular sieve comprises the following steps:
in the first step, 35.22 g of water glass, 1.1 g of sodium hydroxide and 6.45 g of solid aluminum sulfate are mixed with 141 g of distilled water, and then ammonia (containing NH) is added325.5 wt%) 10 g, uniformly mixing, placing into a reaction kettle, crystallizing at 180 ℃ for 48 hours, cooling to room temperature after crystallization, filtering, washing, placing into an oven, and drying at 100 ℃ for 3-4 hours to obtain the silkRaw mordenite powder.
And secondly, taking 25.6g of silica sol (wt 40%), 0.25g of sodium metaaluminate, 1g of sodium hydroxide, 40g of deionized water, 9.5g of 30 wt% tetraethylammonium bromide, 3.9g of 30 wt% tetraethylammonium hydroxide and 3.25g of 30 wt% tetraethylammonium chloride, mixing, and stirring uniformly at room temperature. The pH was adjusted to 13 with 10% aqueous sodium hydroxide solution and left to stand for 6 hours. Then adding 9g of mordenite seed crystal synthesized in the first step, fully stirring, then placing into a reaction kettle, crystallizing for 72 hours at 160 ℃, and drying for 3-4 hours in an oven at 100 ℃ to obtain the symbiotic composite molecular sieve raw powder. Then crystallized at 180 ℃ for 72 hours. The resulting milky white slurry was washed 5 times with deionized water and then dried under vacuum for 12 hours. Obtaining the intergrowth composite molecular sieve raw powder.
30 g of synthesized mixed crystal molecular sieve and 30 g of alumina are mixed, and the mixed powder and dilute nitric acid (0.5 weight percent) are mixed according to the weight ratio of 80: 20 by weight ratio, kneading, molding and drying. Roasting the catalyst precursor for 6 hours at 550 ℃ in air to obtain the catalyst precursor.
The catalyst precursor thus obtained was ion-exchanged 3 times with a 10% by weight ammonium nitrate solution, each time at 90 ℃ for 3 hours, with a sodium content of less than 50ppm after the treatment. And filtering and drying the catalyst precursor subjected to ammonium exchange at room temperature, activating for 4 hours at the temperature of 550 ℃ in the air, and cooling to room temperature to obtain the catalyst.
1g of 50 percent mercerized/ZSM-12 molecular sieve catalyst (the Si/Al molar ratio is 35) (the MTW weight ratio is 30 percent) is added into a 10 ml fixed bed reactor, 50 percent of the catalyst is silicon oxide binder, the particle size is 20 to 40 meshes, and the molar ratio of the reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.1h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 270 ℃ under 0.5MP pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 82.29% and the conversion of 3-methylpentane was 16.44%. In the reaction evaluation, no decrease in the conversion rate was observed in 400 hours.
Example 6:
the preparation method of the mercerization/ZSM-12 molecular sieve comprises the following steps:
first step, water glass 35.22G, sodium hydroxide 1.1 g, solid aluminium sulphate 6.45 g, mixed with 141 g distilled water, then ammonia (containing NH) is added325.5 wt%) of 10 g, uniformly mixing, placing into a reaction kettle, crystallizing at 180 ℃ for 48 hours, cooling to room temperature after crystallization is finished, filtering and washing, and then placing into an oven to dry at 100 ℃ for 3-4 hours to obtain mordenite raw powder.
And secondly, taking 25.6g of silica sol (wt 40%), 0.25g of sodium metaaluminate, 1g of sodium hydroxide, 40g of deionized water, 9.5g of 30 wt% tetraethylammonium bromide, 3.9g of 30 wt% tetraethylammonium hydroxide and 3.25g of 30 wt% tetraethylammonium chloride, mixing, and stirring uniformly at room temperature. The pH was adjusted to 13 with 10% aqueous sodium hydroxide solution and left to stand for 6 hours. Then 8.5 g of mordenite seed crystal synthesized in the first step is added, the mixture is placed into a reaction kettle after being fully stirred, crystallized for 72 hours at 160 ℃, and dried for 3-4 hours in an oven at 100 ℃ to obtain the intergrowth composite molecular sieve raw powder. Then crystallized at 180 ℃ for 72 hours. The resulting milky white slurry was washed 5 times with deionized water and then dried under vacuum for 12 hours. Obtaining the intergrowth composite molecular sieve raw powder.
And roasting the synthesized mixed crystal molecular sieve for 6 hours at 550 ℃ in the air to obtain the catalyst precursor.
The catalyst precursor thus obtained was ion-exchanged 3 times with a 10% by weight ammonium nitrate solution, each time at 90 ℃ for 3 hours, with a sodium content of less than 50ppm after the treatment. And filtering and drying the catalyst precursor subjected to ammonium exchange at room temperature, activating for 4 hours at the temperature of 550 ℃ in the air, and cooling to room temperature to obtain the catalyst.
1g of mercerized/ZSM-12 molecular sieve catalyst (the Si/Al molar ratio is 35) (the MTW weight ratio is 20%) with the content of 100% is added into a 10 ml fixed bed reactor, no adhesive is used, the particle size is 20-40 meshes, and the molar ratio of reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.1h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 270 ℃ under 0.5MP pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 84.25% and the conversion of 3-methylpentane was 17.03%. In the reaction evaluation, no decrease in the conversion rate was observed in 400 hours.
Comparative example 1:
2 g of molecular sieve catalyst with the mass ratio of MOR to MTW being (1: 4) and the particle size being 20-40 meshes is added into a 10 ml fixed bed reactor, and the molar ratio of reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.5h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 300 ℃ under normal pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 15.57% and the conversion of 3-methylpentane was 8.36%. The reaction was evaluated at 150 hours, and the conversion rate began to decrease.
Comparative example 2:
1g of a silk molecular sieve catalyst is added into a 10 ml fixed bed reactor, the particle size is 20-40 meshes, and the molar ratio of reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.5h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 300 ℃ under normal pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 11.78% and the conversion of 3-methylpentane was 12.54%. The reaction was evaluated at 100 hours, and the conversion rate began to decrease.
Comparative example 3:
adding 1g of ZSM-12 molecular sieve catalyst into a 10 ml fixed bed reactor, wherein the particle size is 20-40 meshes, and the molar ratio of the reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.5h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 300 ℃ under normal pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 21.38%, and the conversion of 3-methylpentane was 7.63%. The reaction was evaluated at 300 hours, and no decrease in conversion rate was observed.
Comparative example 4:
adding 1g of ZSM-5/Mercerized (MOR) molecular sieve catalyst into a 10 ml fixed bed reactor, wherein the particle size is 20-40 meshes, and the molar ratio of reaction raw materials is 1: 1 n-hexane and 3-methylpentane at LHSV of 0.5h-1，N2The molar ratio to the reactants was 4:1 and after half an hour at 300 ℃ under normal pressure, the product was analyzed by on-line gas chromatography. The conversion of n-hexane was 82.29% and the conversion of 3-methylpentane was 16.44%. The reaction was evaluated at 350 hours, conversionThe decrease is started.
The mercerization/ZSM-12 molecular sieve catalyst of the method for cracking the carbon hexaalkane has the advantages of high catalytic activity and good stability in the reaction.

Claims (10)

1. A method for cracking carbon hexaalkane takes the carbon hexaalkane as a raw material, the raw material and a catalyst are contacted to react to generate C1-C5 hydrocarbon, wherein the used catalyst comprises the following components in parts by weight:
a) 30-100 parts of mercerized/ZSM-12 intergrowth composite molecular sieve with the Si/Al molar ratio of 10-100; wherein the weight proportion of the ZSM-12 molecular sieve is 10-50%;
b) 0-70 parts of a binder.
2. The process for cracking carbon hexaalkane according to claim 1, wherein the reaction conditions for contacting the carbon hexaalkane raw material with the catalyst are as follows: the reaction temperature is 250-600 ℃, the reaction pressure is 0.1-1 MPa, and the liquid phase space velocity is 0.01-3 hours-1。
3. The method for cracking hexaalkane according to claim 1, wherein the reaction temperature is 270-400 ℃.
4. The method for cracking hexaalkane according to claim 1, wherein the reaction pressure is 0.1-0.5 MPa.
5. The method for cracking hexaalkane according to claim 1, wherein the space velocity of liquid phase is 0.1-1 hr-1。
6. The method of cracking hexaalkanes according to claim 1, wherein said binder is selected from the group consisting of alumina and silica.
7. The method for cracking hexaalkane according to claim 1, wherein the mercerization/ZSM-12 intergrowth composite molecular sieve has a Si/Al molar ratio of 20 to 80.
8. The method for cracking hexaalkane according to claim 1, wherein the weight ratio of ZSM-12 in the mordenite/ZSM-12 intergrowth composite zeolite is 15-40%.
9. The method for cracking carbon hexaalkane according to claim 1, wherein the mercerization/ZSM-12 molecular sieve is used in an amount of 40-90 parts by weight, or a binderless mercerization/ZSM-12 intergrowth composite molecular sieve without a binder is used.
10. The carbon hexaalkane cracking method of claim 1, wherein the mercerization/ZSM-12 intergrown composite molecular sieve is prepared by the following steps: firstly, a silicon source, an aluminum source, a template agent R and water form a mixture, and the molar ratio of the mixture is as follows: 37.5-50% of Si/Al; h2O/SiO2＝15～30；R/SiO20.1 to 0.5; and adding an alkali source into the mixture of tetraethylammonium hydroxide and tetraethylammonium chloride as a template agent R to form a synthetic reaction system of ZSM-12, adding mordenite, continuously stirring until the mixture is uniform, crystallizing at the temperature of 120-200 ℃ for 20-120 hours to obtain a crystallized product, and washing and drying the crystallized product to obtain the mercerization/ZSM-12 intergrowth composite molecular sieve.
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CN1756829A (en) * 2003-02-28 2006-04-05 埃克森美孚研究工程公司 C6 recycle for propylene generation in a fluid catalytic cracking unit
CN101094906A (en) * 2004-12-30 2007-12-26 埃克森美孚研究工程公司 Fcc feed injection system
CN102373069A (en) * 2010-08-23 2012-03-14 中国石油化工股份有限公司 Method used for C6-alkane cracking

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1756829A (en) * 2003-02-28 2006-04-05 埃克森美孚研究工程公司 C6 recycle for propylene generation in a fluid catalytic cracking unit
CN101094906A (en) * 2004-12-30 2007-12-26 埃克森美孚研究工程公司 Fcc feed injection system
CN102373069A (en) * 2010-08-23 2012-03-14 中国石油化工股份有限公司 Method used for C6-alkane cracking

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