Research On Extrusion Of ZSM-5 Zeolite Catalyst For Mathanol Aromatization

In this paper,methanol aromatization(MTA)was used as a model reaction,combined with BET,mercury injection and other characterization methods,and the influence of molding conditions on the performance of ZSM-5 zeolite catalyst(aromatic yield,aromatic selectivity and side compression strength,etc.).On the basis of stable synthesis of ZSM-5 molecular sieve in the laboratory,the pilot-scale scale preparation of ZSM-5 molecular sieve was carried out with 100 L dynamic synthesis kettle of Qi Chuangxin Material Technology Co.,Ltd.The characterization and evaluation results showed that the morphology and methanol aromatization properties of the ZSM-5 zeolite prepared by amplification were not significantly different from those of the pilot sample,but the crystallinity of the ZSM-5 zeolite was slightly lower than that of the pilot sample.This difference may be due to the fact that the purity of the industrialgrade raw materials used in the pilot test was lower than that of the laboratory raw materials.The effects of forming conditions on the physical and chemical properties of the catalyst were investigated by single factor experiment,such as nitric acid,SB powder,sesbania powder,gouacine ratio and reaming agent type.The results showed that:(1)The lateral compressive strength of the forming catalyst firstly increased and then decreased with the increase of the amount of nitric acid,and gradually decreased with the increase of the ratio of water powder,and gradually increased with the increase of the amount of Sb powder and the roasting temperature.The side compressive strength of catalyst particles decreased after adding reamer.(2)With the increase of nitric acid dosage and roasting temperature,the aromatic selectivity and yield increased first and then decreased;The ratio of gouache,the amount of Sb powder and sesbania powder had little effect on the catalytic performance of the catalyst.(3)The catalytic performance of forming catalyst using PEG20000 as pore reamer is better than that of PEG200,methyl cellulose and urea pore reamer.The effects of the dosage of Sb powder,nitric acid,sescyanine powder and PEG20000 on the performance of the ZSM-5 molding catalyst were comprehensively investigated by orthogonal experiment with the side pressure strength and aromatic yield of the granular catalyst as the objective function.Finally,the molding conditions were determined as follows:Nitric acid 15%,SB powder 35%,sesbania powder 3%,PEG20000 dosage 5%,gouache ratio 0.9.Based on the catalyst particles prepared under relatively suitable forming conditions,the effect of technological conditions on the MTA process was investigated with the yield of aromatics as the objective function.The results showed that:(1)The higher the space velocity of methanol,the lower the aromatics selectivity and mass yield,and the more easily the catalyst was deactivated;(2)Temperature has a certain effect on the selectivity and yield of aromatic hydrocarbons,but has little effect on methanol conversion.Finally,the operating conditions were determined as follows:evaluation temperature 450℃,methanol mass space velocity 1.5 h-1,and under these operating conditions,the highest aromatic yield and aromatic selectivity were 24.7%and 59.7%.