Basic Study Of Light Aromatics Production From 2-methylfuran With Methanol Over Modified ZSM-5 Zeolite

Light aromatic hydrocarbons such as benzene,toluene and xylenes are important chemical industry feedstocks,which are mainly derived from catalytic reforming of petroleum components.Due to diminishing quantities of fossil fuels,lignocellulosic biomass has received widespread attention as the only renewable carbon source due to its large availability and economic factors.Furans can form light aromatic hydrocarbons such as benzene,toluene and xylene under the catalysis of zeolites,but there are still problems like low selectivity of light aromatic hydrocarbons and high carbon deposition rate of catalyst.In this paper,the coupling of reaction and energy can be realized by co-catalytic conversion of methanol and 2-methylfurans.At the same time,the effects of pore size,acid type and the amount of acid of hierarchical zeolites and metal modified hierarchical zeolites are studied.The main results as follows:The experimental conditions were optimized for the reaction temperature,weight hourly space velocity and carrier gas flow rate.The selectivity of light aromatics and carbon deposition rate were investigated.When the reaction temperature was 550?,weight hourly space velocity was 4 h^-1 and carrier gas flow rate was 60 ml/min,the reaction has the highest carbon yield of light aromatics and a relatively low carbon deposition rate.Catalytic performance of alkali-treated hierarchical zeolites:the carbon deposition rate are reduced when the catalysts treated with different alkalis,and the carbon yield of light aromatic hydrocarbons is significantly improved when zeolites treated by the NaOH and NaHCO₃.The carbon yield of light aromatic increased first and then decreased with the concentration of NaOH increased from 0.1 M to 0.5 M,but still higher than unmodified zeolites,reaching a maximum at 0.3 M?70.45%?which is 1.63 times of unmodified zeolites.This is because after alkali treatment the formation of multi-stage pore structure and the increase of Lewis acid.The carbon yield of light aromatics showed a downward trend with the increase of alkali-treated time.The selectivity of light aromatics showed an upward trend when the ion exchange time of ammonium chloride increased from 1 h to 8 h.Using isotope tracer by labeling methanol found there are two main ways methanol participates in the reaction:one is methanol generates ethylene which converted to aromatics with furans by Diels-Alder reaction,two is methanol participates the alkylation of aromatics.There are many types of carbon deposited on the catalysts after the reaction,the main type of carbon deposited on the catalysts has a weight loss peak around 550?.Catalytic performance of mental modified hierarchical zeolites:Ga?Zn?Mo?W four kinds of mental modified hierarchical zeolites,only W/ZSM increased the carbon yield of light aromatics?70.62%?,the carbon deposition rate on the catalysts significantly increased.Using different methods to load Zn,the results showed the rank order of carbon yield of light aromatics was excessive wetness impregnation>mechanical mixing>incipient wetness impregnation.