Reducing coke formation in the catalytic fast pyrolysis of bio-derived furan with surface modified HZSM-5 catalysts

Abstract

In order to reduce coke yield during biomass catalytic fast pyrolysis process, MgO and 2,4-dimethylquinoline (2,4-DMQ) were selected to deposit the external acid sites of HZSM-5. Both MgO and 2,4-DMQ deposition could cause a reduction in total acid sites (both weak acid sites and strong acid sites) and external acid sites of HZSM-5.The modified catalysts were used for catalytic conversion of bio-derived furan. For MgO/HZSM-5 catalyst, the effects of deposited amount and deposited time were studied. The carbon yields of aromatics, C 2 -C 5 olefins, total chemicals, CO 2 and CO increased at first and then decreased slightly when deposited amount increased, while the carbon yield of coke decreased first and then increased gradually. Besides, with the deposited time increased, the carbon yields of petrochemicals, CO 2 and CO increased greatly, whereas that of coke decreased. For 2,4-DMQ/HZSM-5 catalyst, the effects of 2,4-DMQ treatment amount and treatment time were investigated. The experimental results illuminated that the increase in 2,4-DMQ treatment amount or treatment time could retard the generation of target products, CO 2 and CO but promote coke formation.

Modification and regeneration of HZSM-5 catalyst in microwave assisted catalytic fast pyrolysis of mushroom waste

“…It was important to point out that the relative contents of hydrocarbons were rarely low during the microwave assisted non-catalytic fast pyrolysis of MW, however, a positive increase in hydrocarbons could be realized by the application of parent and different EDTA modified HZSM-5 catalysts, and the modification time of 2 h (i.e., 2H-Z5) was found to be the optimal condition as the most prominent growth of hydrocarbons could be attained. The underlying reason was that, as mentioned before, the unique molar structure and shape selectivity of HZSM-5 played a determining role in increasing the selectivity to fuel range hydrocarbons through various chemical reactions including isomerization, oligomerization, and aromatization [25], which could be reflected in Fig. 5 as discussed below.…”

Optimizing anti-coking abilities of zeolites by ethylene diamine tetraacetie acid modification on catalytic fast pyrolysis of corn stalk

“…To verify the two factors above, H + ions exchange method is further used to treat EDTA-1H. Procedures are as followed [25]: 1 mol/L HCl and the sample were mixed with the mass ratio of 10:1 and treated at 90 °C for 3 h, followed by vacuum filtration combing with deionized water washing. Finally, the sample was dried and analyzed by NH 3 -TPD.…”

Catalytic Conversion of Furan to Hydrocarbons using HZSM‐5: Coking Behavior and Kinetic Modeling including Coke Deposition

“…In our previous study, we have investigated the catalytic characteristics of several model compounds from biomass pyrolysis and found that serious coking happened in the catalytic conversion of furan, which is an important reaction intermediate for the CFP of biomass (up to 50 % of carbon yield) . Coke deposition leads to a product selectivity change caused by coverage of the active sites and pore blockage . Decreasing the number of active sites and narrowing of pores/channels happen initially.…”

“…[15] Coke depositionl eads to ap roduct selectivityc hangec aused by coverageo ft he active sites and pore blockage. [16,17] Decreas-ing the number of active sites and narrowing of pores/channels happen initially. Then conversion decreases sharply when the cokings ignificantly blocks the pores.T he selectivity change causedb yc oke deposition can be explained by diffusivityc hanges of the molecules in the zeolitep ore volume upon the formation of coke.…”