Catalytic Upgrading of Coal Pyrolysis Gaseous Tar over Hierarchical Y-Type Zeolites Synthesized Using a Microwave Hydrothermal Method

Abstract

In this work, a series of hierarchical Y-type zeolites were rapidly synthesized using organosilane as templates through a microwave hydrothermal method. The effects of hierarchical Y-type zeolites on the product composition and the yield of light aromatics in gaseous tar from coal pyrolysis were studied. The results showed that the hierarchical Y-type zeolites showed better catalytic properties than the traditional microporous zeolite in the catalytic conversion of gaseous tar and can greatly increase the yield of light aromatics in the pyrolysis products. The hierarchical Ytype zeolite has abundant mesopores, which contribute to the access of bulky molecules into the porous channel and the contact of active sites. Meanwhile, the mesopores reduce the diffusion length of the reaction products, thus promoting the conversion of heavy components in gaseous tar to light aromatics.

Catalytic Conversion of Coal and Biomass Volatiles: A Review

“…Particularly, the oxygen concentration is usually very high, reaching up to 40–50 wt %. The heteroatoms present in bulky molecules must be partially or totally removed during coal/biomass transformation to produce compounds that are suitable for commercial applications. , …”

“…The heteroatoms present in bulky molecules must be partially or totally removed during coal/biomass transformation to produce compounds that are suitable for commercial applications. 24,25 This review outlines the main progress performed in recent years on conversion of coal and biomass volatiles over the CFP process and gasification reforming. Given that the complex pyrolysis behavior of coal/biomass, the principles of volatile reforming are summarized in section 2.…”

State of the Art and Perspectives of Hierarchical Zeolites: Practical Overview of Synthesis Methods and Use in Catalysis

“…In the end, it was seen that a higher TPOAC concentration increased the total pore volume from 0.42 to 0.54 cm 3 g −1 , wherein the mesopore volume slightly increased (from 0.10 to 0.28 cm 3 g −1 ) at the expense of micropore volume (from 0.32 to 0.26 cm 3 g −1 ). [ 310 ] Moreover, a high specific surface area of 810 m 2 g −1 was observed, which was higher compared to a specific surface area of 764 m² g −1 in the first study, where no microwaves were used. Both methods thus proved to be appropriate for synthesizing outstanding hierarchical zeolite Y.…”

“…[308] The final mesoporogen, namely, TPOAC, has been previously discussed in the desilication of zeolite Y, however, this molecule can also be useful in bottom-up approaches. This is done by Venkatesan et al [309] and Lv et al [310] Venkatesan et al started from a seed gel in combination with TPOAC as amphiphilic organosilane. Herein, the crystallization started with a long nucleation period, followed by rapid crystal growth.…”

“…[ 309 ] and Lv et al. [ 310 ] Venkatesan et al. started from a seed gel in combination with TPOAC as amphiphilic organosilane.…”