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A. Zhang and C. Li
Mesoporous molecular sieve catalysts with regular pore structure and shapeselective catalytic effect have been developed. Mesoporous molecular sieves as catalysts can significantly reduce the formation of non-condensable gasses and improve
the yield of liquid products. It has been proved in petrochemical, waste plastic cracking, and other research fields, and similar results have been obtained in oil cracking.
However, there are many weaknesses, such as the acid content of pyrolysis products
is high, and the acid value is about 120 mg KOH/g. According to the literature, the
development of catalysts is limited to the synthesis of catalysts used in petroleum
refining, and ignoring the negative impact of high acid value of pyrolysis products on
fuel performance. Twaiq and Sang et al. attempted to carry out triglyceride catalytic
cracking using a small pore-mesoporous composite catalytic material. It was found
that the composite material with this structure has better gasoline fraction selectivity.
The reaction conditions for obtaining the best gasoline fraction yield are: temperature
440 °C, the ratio of fatty acid to catalyst is 9.64, and the weight hourly space velocity
(WHSV) is 3.66. H-1. Shinae Jun et al. reported the synthesis of a new material
for mesoporous carbon molecular sieves and studied its structure. The results show
that carbon molecular sieve is an inert material, which can ensure the stability of its
own skeleton structure regardless of the acid-base environment. Mesoporous silica
molecular sieves (such as MCM-41) will undergo structural instability under alkaline
conditions and cause skeleton collapse. In addition, mesoporous carbon molecular
sieves have similar mesoporous structure, high specific surface area and thermal stability to mesoporous silica molecular sieves (such as MCM-41), but their catalytic
properties have not been studied. Zhang FQ and other studies have shown that carbon
molecular sieve as a catalyst carrier has the advantages of high dispersion of active
phase, reaction heat removal in time, reduction of polycondensation and condensation, etc. It is an ideal catalyst carrier. Therefore, if the basic metal compound is
uniformly supported on the surface of the mesoporous carbon molecular sieve, the
alkaline mesoporous carbon molecular sieve is created as a grease cracking catalyst,
and the uniform mesoporous structure can be utilized to avoid the limitation of the
molecular sieve having a smaller pore size in the cracking reaction. It can also produce >C5 hydrocarbons (for liquid fuels), ensure higher conversion of raw materials,
reduce the occurrence of carbon formation, and improve the activity, selectivity, and
service life of the catalyst. In addition, the uniform, highly dispersed surface alkali
center can not only improve its catalytic activity, but also change the reaction process, convert the higher fatty acid produced by the cracking into carboxylate and
decompose it to obtain low-oxygen bio-hydrocarbon fuel oil (alkane, olefin mixed
fuel).), and the catalytic reaction kinetics, reaction mechanism, and surface physicochemical properties in this new catalytic system are different from the traditional
catalytic system, many of which need to be studied and explored in-depth.
Recent studies have found that alkali metal elements can exhibit strong acid binding during catalytic cracking and can significantly reduce the carboxylic acid content
of pyrolysis products. The mechanism is to form a carboxylate with the carboxylic
acid produced by the cleavage, and then the carboxylate is decomposed at a set temperature to obtain an alkane or olefin mixture having better combustion properties.
This reaction process effectively reduces the activation energy of the reaction, and
A. Zhang and C. Li
Mesoporous molecular sieve catalysts with regular pore structure and shapeselective catalytic effect have been developed. Mesoporous molecular sieves as catalysts can significantly reduce the formation of non-condensable gasses and improve
the yield of liquid products. It has been proved in petrochemical, waste plastic cracking, and other research fields, and similar results have been obtained in oil cracking.
However, there are many weaknesses, such as the acid content of pyrolysis products
is high, and the acid value is about 120 mg KOH/g. According to the literature, the
development of catalysts is limited to the synthesis of catalysts used in petroleum
refining, and ignoring the negative impact of high acid value of pyrolysis products on
fuel performance. Twaiq and Sang et al. attempted to carry out triglyceride catalytic
cracking using a small pore-mesoporous composite catalytic material. It was found
that the composite material with this structure has better gasoline fraction selectivity.
The reaction conditions for obtaining the best gasoline fraction yield are: temperature
440 °C, the ratio of fatty acid to catalyst is 9.64, and the weight hourly space velocity
(WHSV) is 3.66. H-1. Shinae Jun et al. reported the synthesis of a new material
for mesoporous carbon molecular sieves and studied its structure. The results show
that carbon molecular sieve is an inert material, which can ensure the stability of its
own skeleton structure regardless of the acid-base environment. Mesoporous silica
molecular sieves (such as MCM-41) will undergo structural instability under alkaline
conditions and cause skeleton collapse. In addition, mesoporous carbon molecular
sieves have similar mesoporous structure, high specific surface area and thermal stability to mesoporous silica molecular sieves (such as MCM-41), but their catalytic
properties have not been studied. Zhang FQ and other studies have shown that carbon
molecular sieve as a catalyst carrier has the advantages of high dispersion of active
phase, reaction heat removal in time, reduction of polycondensation and condensation, etc. It is an ideal catalyst carrier. Therefore, if the basic metal compound is
uniformly supported on the surface of the mesoporous carbon molecular sieve, the
alkaline mesoporous carbon molecular sieve is created as a grease cracking catalyst,
and the uniform mesoporous structure can be utilized to avoid the limitation of the
molecular sieve having a smaller pore size in the cracking reaction. It can also produce >C5 hydrocarbons (for liquid fuels), ensure higher conversion of raw materials,
reduce the occurrence of carbon formation, and improve the activity, selectivity, and
service life of the catalyst. In addition, the uniform, highly dispersed surface alkali
center can not only improve its catalytic activity, but also change the reaction process, convert the higher fatty acid produced by the cracking into carboxylate and
decompose it to obtain low-oxygen bio-hydrocarbon fuel oil (alkane, olefin mixed
fuel).), and the catalytic reaction kinetics, reaction mechanism, and surface physicochemical properties in this new catalytic system are different from the traditional
catalytic system, many of which need to be studied and explored in-depth.
Recent studies have found that alkali metal elements can exhibit strong acid binding during catalytic cracking and can significantly reduce the carboxylic acid content
of pyrolysis products. The mechanism is to form a carboxylate with the carboxylic
acid produced by the cleavage, and then the carboxylate is decomposed at a set temperature to obtain an alkane or olefin mixture having better combustion properties.
This reaction process effectively reduces the activation energy of the reaction, and