Zsm-22 zeolite has an iZmportant role in the catalysis of important reactions in petroleum refining and petrochemical industries.zsm-22 zeolite The zeolite has excellent catalytic activity for the hydroisomerization of normal paraffins. This reaction is a key process for petroleum refinement and petrochemical production, because it can significantly reduce the content of light products in crude oil. This can also increase the yield of fuels such as gasoline and diesel. The zeolite has high isomerization activity and suppressed decomposition activity in the normal paraffin hydroisomerization reaction. This enables highly efficient conversion of heavy products such as naphtha and kerosene to lighter hydrocarbons. The zeolite can be classified according to its pore structure. It is possible to use a variety of catalysts in the normal paraffin hydroisomerization process with this type of zeolite.
The present invention relates to a method for producing a zsm-22 zeolite carrier with an organic template that is used as a catalyst in the hydroisomerization of normal paraffins.zsm-22 zeolite The method is characterized by firing a mixture of a carrier and the organic template containing zeolite under an atmosphere comprising hydrogen and molecular oxygen. The supported amount of active metal deposited on the carrier is 0.001 to 20% by mass based on the total weight of the mixture. This is a relatively low amount, which can make the catalyst more economical.
In the present invention, a core-shell ZSM-22 zeolite is prepared by adding an organic template to a zeolite synthesis solution for shell synthesis. This is a useful approach, which enables the preparation of core-shell zeolite without the need for post-synthesis and recrystallization of the shell. The invented method is also simple and convenient, making it particularly suitable for the preparation of core-shell zeolite.
The zeolite used in the present invention has a 10-membered ring one-dimensional pore structure and is preferably of the AEL, EUO, FER, HEU, MEL, MFI, NES, TON, MTT, WEI, *MRE or SSZ-32 type. These are skeletal structures defined by the Structure Commission of The International Zeolite Association for different classifications of molecular sieve type zeolites.
The zeolite is blended with an inorganic oxide, which can be selected from the group consisting of alumina, silica, titania, zirconia, magnesia, ceria, and a combination thereof, at a temperature of 250 to 350 degC in the presence of oxygen. The inorganic oxide is dissolved in water, and the resulting solution is sprayed onto the surface of the ZSM-22 zeolite, and then subjected to ion exchange treatment. The ion exchange treatment is carried out under conditions of aqueous ammonium ions or protons, preferably in the presence of protons, so that a large number of organic templates can be removed from the zeolite pores. The zeolite and the inorganic oxide are then ground into a fine powder, whereafter they are mixed with each other and kneaded with a kneader or the like to form a slurry. The slurry is then dried and ground again to form the zeolite carrier. This slurry can be used for the hydroisomerization of normal naphtha and kerosene in an oxidation-reduction cycle, or it can be used in other conventional processes for the formation of heavier hydrocarbons.
