Department of Chemical Engineering
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Item Multi reaction apparent kinetic scheme for the pyrolysis of large size biomass particles using macro-TGA(Elsiever, 2018-05-15) Sheth, P.N.In the present study, the pyrolysis of biomass is proposed by one step multi reaction apparent model. It is expressed as parallel production of bio-oil, gases and charcoal. Macro TGA of Jatropha de-oiled cake is performed at temperatures ranging from 350 °C to 700 °C. The volatiles released during pyrolysis exits from the top of the reactor and are cooled in a two-stage condenser followed by an ice trap. The weight reduction variation of the biomass with time, product yield and composition of non condensable gases are measured and used to develop the apparent kinetic model. The corresponding apparent kinetic parameters are estimated by minimizing the square of the error between simulated values of residual weight fraction and experimental values using non-traditional optimization technique logarithmic differential evolution (LDE). The weight reduction with time suggests that the pyrolysis of de-oiled cake is carried out in three stages. The maximum liquid yield obtained is 31.2% at 500 °C, which further decreases with an increase in temperature. The model predicted values of residual weight fractions and yield of products are matching very well with the experimental data for all reactor temperature.Item Recent progress in thermochemical techniques to produce hydrogen gas from biomass: A state of the art review(Elsiever, 2019-10-04) Sheth, P.N.The present work comprehensively covers the literature that describes the thermochemical techniques of hydrogen production from biomass. This survey highlights the current approaches, relevant methods, technologies and resources adopted for high yield hydrogen production. Prominent thermochemical methods i.e. pyrolysis, gasification, supercritical water gasification, hydrothermal upgrading followed by steam gasification, bio-oil reforming, and pyrolysis inline reforming have been discussed thoroughly in view of the current research trend and latest emerging technologies. Influences of important factors and parameters on hydrogen yield, such as biomass type, temperature, steam to biomass ratio, retention time, biomass particle size, heating rate, etc. have also been extensively studied. Catalyst is a vital integrant that has received enough attention due to its encouraging influence on hydrogen production. Literature confirms that hydrogen obtained from biomass has high-energy efficiency and potential to reduce greenhouse gases hence, it deserves versatile applications in the coming future. The study also reveals that hydrogen production through steam reforming, pyrolysis, and in-line reforming deliver a considerable amount of hydrogen from biomass with higher process efficiency. It has been identified that higher temperature, suitable steam to biomass ratio and catalyst type favor useful hydrogen yield. Nevertheless, hydrogen is not readily available in the sufficient amount and production cost is still high. Tar generation during thermochemical processing of biomass is also a concern and requires consistent efforts to minimize it.