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Highly active and heat-resisting strong acid-promoted W/HZSM-5-based catalysts, W-Zn (La, Nb)-H2SO4/HZSM-5, for non-oxidative dehydro-aromatization of methane have been developed. Over a W-Zn-H2SO4/H2SO4/HZSM-5 catalyst and under the reaction conditions of 1 123 K, 0. 1 MPa, and GHSV=1 500 mL/h per gram cat., methane conversion (XCH4) reached 23%, with a selectivity to benzene at 97% and an amount of coking for 3 h operation at 0. 02% of the weight of the catalyst used. During a stability test at 1 073 K for 3 h, XCH4 had been maintaind at about 21.5% over the W-Zn-H2SO4/HZSM-5 catalyst,whereas dropped gradually to 13% from 19％ in the initial stage over the Mo-Zn-H2SO4/HZSM-5, demonstrating that the former has a better heat-resisting peculiarity than the latter. The results of investigation of optimization of the catalyst composition showed that the optimal W-loading on the HZSM-5[n (Si)/n (Al)=38] zeolite support was about 2.5％, and that an optimal match-ratio existed among the W and the promoters, Zn (or La or Nb) and H2SO4. The experimental results also indicated that the promoting effects of Zn and La were more pronounced than Nb.
Highly active and heat-resisting strong acid-promoted W / HZSM-5-based catalysts, W-Zn (La, Nb) -H2SO4 / HZSM-5, for non-oxidative dehydro- -Zn-H2SO4 / H2SO4 / HZSM-5 catalyst and under the reaction conditions of 1 123 K, 0.1 MPa, and GHSV = 1 500 mL / h per gram cat., Methane conversion (XCH4) reached 23% with a selectivity to benzene at 97% and an amount of coking for 3 h operation at 0.2% of the weight of the catalyst used. During a stability test at 1 073 K for 3 h, XCH4 had been maintaind at about 21.5% over the W-Zn-H2SO4 / HZSM-5 catalyst, unsupproding gradually to 13% from 19% in the initial stage over the Mo-Zn-H2SO4 / HZSM-5 demonstrating that the former has better heat-resisting peculiarity than the latter . The results of investigation of optimization of the catalyst composition showed that the optimal W-loading on the HZSM-5 [n (Si) / n (Al) = 38] zeolite support was about 2.5%, and that an optimal match-ratio former among the W and the promoters, Zn (or La or Nb) and H2SO4. The experimental results also indicated that the promoting effects of Zn and La were more pronounced than Nb.