Part A: Investigation of the Interplay of Reaction and Transport within Biomass Particle during Fast Pyrolysis
Pyrolysis of biomass and waste converts it to bio-oil, which can be further upgraded to fuels and chemicals. Decomposition of the feed particle, within the pyrolysis reactor, governs the product distribution, and hence the yield and the composition of bio-oil. Complex and often unknown decomposition chemistry, high temperatures and short residence times of the volatile products in the reactor and an interplay between reaction kinetics and heat and mass transport effects within the particle make it extremely difficult to understand the particle level decomposition of biomass. In this work, we applied an integrated experimental and theoretical (a particle level model) approach to investigate the fundamentals of particle level decomposition, using glucose as the model biomass compound. Pyrolysis experiments were conducted in a micropyrolyzer and products were analysed using an online GC-MS system. Initial experiments were performed in an isothermal and reaction controlled regime using micron size thin film of glucose and the effect of reaction temperature on the product distribution was studied. To describe the reaction chemistry theoretically, a kinetic model was fitted to this transport free experimental pyrolysis data. Later, by using different sizes of glucose particles, experiments were performed to investigate the effect of transport on pyrolysis product distribution. Simultaneously, a particle level model comprising of energy and species mass conservation equations was developed, as heat and mass transport occurs simultaneously along with pyrolysis reactions, considering the entire particle as a control volume. Conservation equations consist of generation, convective and diffusive transport and accumulation terms. Unlike using lumped models for the pyrolysis reactions, the aforementioned kinetic model fitted to transport free experimental data (thin-film pyrolysis), is incorporated into the mass conservation equations. Changes in particle porosity and thermal conductivity and shrinkage of the particle during the pyrolysis process were also taken into account. Further, the model equations and boundary conditions were non-dimensionalized to group difficult to measure variables/properties/parameters into non-dimensional numbers like Biot, Pyrolysis, Peclet, Damkohler and Sherwood numbers that represent characteristic reaction and transport timescales. Solving the non-dimensional particle level model and validating it with the in-house experimental pyrolysis data will enable us to capture the interplay of pyrolysis reactions and transport within the biomass particle.
Part B: Catalytic Influence of Naturally Occurring Salts on Biomass Pyrolysis Chemistry
Most of the biomass contains naturally occurring inorganic metal ions like sodium (Na+), potassium (K+), calcium (Ca2+) and magnesium (Mg2+) which plays an important catalytic role during pyrolysis and considerably modifies the pyrolysis product distribution. Despite of many research in biomass pyrolysis, the mechanistic insight of the catalytic role of aforementioned metal ions has not yet been investigated in detail. In this work, we present the biomass (taking glucose and cellobiose as model compounds) decomposition mechanisms in the presence of Na+, K+, Ca2+ and Mg2+ using a density functional theory approach. Simultaneously, the pyrolysis of micron size thin-film of glucose an cellobiose samples (which is homogeneously mixed with Na+, K+, Ca2+ and Mg2+ metal ions) is performed and pyrolysis product distribution is obtained. The experimentally observed pyrolysis product distribution is used to validate the glucose and cellobiose decomposition pathways in the presence of Na+, K+, Ca2+ and Mg2+ metal ions.
Bio-sketch: Khursheed was born in India and completed his undergraduate studies in chemical engineering in year 2006 from Shivajirao S Jondhale College of Engineering, University of Mumbai (India). Later, he moved to Institute of Chemical Technology (Formerly known as UDCT), Mumbai (India) to pursue his graduate studies in chemical engineering. He completed master degree in chemical engineering in the year 2009 under the supervision of Professor Vilas G. Gaikar and later continued his doctoral studies in chemical engineering under the same guide. During Master’s, he worked on adsorption of carbon dioxide on synthetic functional polymers. His doctoral research involved investigation of “Renewable biofuel form ligno-cellulosic and waste biomass”. He received doctorate degree in Chemical Engineering in year 2015. He holds six international research publication as an outcome of his research. He received two IIChE (Indian Institute of Chemical Engineers) awards for his best 2nd technical paper published in Indian Chemical Engineer Journal, 2015. After PhD, he joined a petrochemical company named Fossil Liquid and Mineral Exim Pvt. Ltd., Wada, Maharashtra (India). He performed lab scale R&D on bitumen oxidation, polymer modified bitumen and bituminous coating and also monitored a pilot plant of 10000 kg capacity for bitumen oxidation. He worked for Fossil Liquid and Mineral Exim Pvt. Ltd. from September, 2014 to February, 2016. Later, from June-2016 to till date, he is working as postdoctoral research fellow in School of Chemical and Biomedical Engineering at Nanyang Technological University under the supervision of Assist. Prof. Samir H. Mushrif . His postdoctoral research involves an integrated experimental and theoretical approach to improve biomass pyrolysis technology.