This project aims at conversion of waste tars compounds in synthesis gas derived from biomass gasification, into valuable gases using one step catalytic process. The importance of this research is driven by three significant factors: (a) the detrimental effect of tars in downstream gasification processes, (b) the carginogenic nature of tars (multi-ring aromatic hydrocarbons), which makes their disposal impossible and (c) the potential to increase the efficiency of the overall biomass gasification process by transforming byproducts to valuable products.
The key objective this research is to test the hypothesis that zeolite-based materials with hierarchical pore network architecture will eliminate the diffusion limitations of the heavy multi-ring aromatic compounds hydrocarbons present in tars and will accommodate their cracking. Moreover, they will provide the open framework structure for the incorporation of transition metals, which will enhance the reforming reactions of the produced lighter hydrocarbons to synthesis gas.This project will focus on the synthesis, characterization and evaluation of various microporous-mesoporous zeolites with pore network and metal active sites that will enhance the cracking and reforming of heavy aromatic hydrocarbons to synthesis gas. Two types of zeolite precursors with different acidity, crystal size and Si/Al ratios will be modified. Mesoporosity will be introduced in the zeolites by employing controlled desilication pathways and surfactant assisted method. Various transition metals will be incorporated in the micro/mesoporous surface of the zeolites using wet impregnation method. The effectiveness of the modified zeolites to crack and subsequently reform the tars into valuable synthesis gas will be evaluated in laboratory-scale fixed bed reactor. Model compounds will be used to simulate the complex mixture of the tars. Advanced materials characterization and liquid and gas analysis techniques will be used to gain fundamental understanding of the cracking and reforming reaction mechanism of tars.
PI?s hypothesis lies on the idea that utilizing the advantages of zeolites with hierarchical porosity and transition metals would be ideal and would create great potential for transforming the unwanted tars to valuable energy. Thus, this research will make fundamental contributions via: (a) the discovery and the advanced characterization of hierarchical pore zeolite-based materials for the effective cracking of heavy hydrocarbons present in tars; (b) the identification of effective transition metals for the reforming of light hydrocarbons to synthesis gas; and c) the understanding of the nature and the reactivity of multi-ring aromatic hydrocarbons present in tars.
In addition to the technological impact on the biofuel industry, this project will also have educational impact: a) it will contribute to the education of both undergraduate and graduate students; b) it will bring high school students during the summer for a one-week-long introduction to engineering technologies through the NSF RET program; and c) it will attract and give the opportunity to teachers from districts with financial challenges to elevate their professional carrier and to stimulate their post-elementary students to pursue an engineering education in college through the NSF Joule Fellow and da Vinci programs.
