Pilot Plant Test For Alkylation Of Toluene With Methanol Into Para-Xylene Over Modified HZSM-5Zeolite

Para-Xylene has a large market demand and are widely used in the fields, such as polyester fibers, resins etc. As oil resources drying up, however, the non-oil route of p-xylene production becomes increasingly important. Because of its low raw material prices, high product selectivity and less investment costs, Alkylation of Toluene with Methanol into Para-Xylene over kinds of zeolites has attracted much attention in recent years. However, the catalysts of zeolite will deposite carbon during reaction inevitably result in deactivation by coking. Finding effective and sample way to restrain the process of carbon deposition to improve the catalysts stability has been the important tobic of realizing the industrializing of this technology.In this article Si-P-Mg modified HZSM-5was used as parent catalyst, the PX is first generated, to ensure high selectivity of PX in the products. Then, on the basis of the modified catalyst, second silicone modification and Ni modification, not only further adjust the catalyst pore structure, the orifice size and the distribution of acid center, but also metal Ni hydrogenation function appear. Ni modified HZSM-5catalysts were prepared using for toluene alkylation with methanol in hydrogen atmosphere, dealkylation of macromolecular hydrocarbon material was promoted by hydrogenation properties of Ni, the generation chance of methane was improved and generated low-carbon alkene was hydrogenated to reduce the proportion of low-carbon alkene. The generation of carbon precursors was inhibited while the process of carbon deposition was postponed, the stability of catalyst was improved.On the fixed bed reactor, the amplification of reaction conditions in the hydrogen atmosphere are investigated over the modified molecular sieve. Under the optimized reaction conditions of460℃, pressure was0.2MPa, toluene/methanol=6(molar ratio), WHSV=4h"’(toluene and methanol as feed), H2/(T+M)=H2O/(T+M)=2(molar ratio). the toluene conversion (CT) was8-12%and the selectivity of para-xylene (Spx) kept at93%. The catalyst was not deactivation during the continuous reaction beyond1100h.