Pinakeswar Mahanta

Determination and comparison of kinetic parameters of low density biomass fuels

Biomass has great potential as a clean, renewable feedstock for producing modern energy carriers. Low density biomass, such as rice husk, sawdust, bamboo dust, etc., can provide a continuous supply of liquid and gaseous fuels through thermochemical conversion processes. In the present study, kinetics of the thermal decomposition of three biomasses such as rice husk, sawdust, and bamboo dust were evaluated under air atmosphere from ambient temperature to 1000 °C at a heating rate of 10 °C min−1. Two distinct reaction zones were observed for all the three biomasses. From the thermogravimetric (TG) and differential TG curves, the activation energies, pre-exponential factors, and order of reaction were determined for both the reaction zones. Experimental results were validated numerically and these results are found to be very close to the numerical results. As observed, thermal decomposition rates in the first reaction zone were found to be significantly higher than those in the second reaction zone.

Recent Inventions in Biodiesel Production and Processing- A Review

Since recent past the research on biodiesel production and processing has got high momentum as evidenced from the large number of publications and patents on the subject. Many novel and improved protocols based on chemical, physical, and biological approaches have been reported that addresses the critical issues related to biodiesel production, recovery, purification, and associated recovery of high valued secondary products. Biodiesel typically comprises lower alkyl fatty acid (chain length C14-C22) esters of short-chain alcohols, primarily, methanol or ethanol. Various methods, such as pyrolysis, micro-emulsification, ozonization, ultrasonication, and transesterification have been reported for the production of biodiesel from vegetable oil. Among these, transesterification is appeared as attractive and widely accepted technique. This transesterification is mostly done chemically or enzymatically using lipase as biocatalyst. Lipase catalysis has received increasing attention due to its certain advantages over the conventional chemical catalysis. However, poor operational stability and low focus on the application of lipase for the biodiesel production are some of the important obstructing factors that impede the progress of the enzyme-based process. In addition to the transesterification step, separation of the ester from the reaction mixture, purification of the ester and glycerol, maintenances of appropriate fuel quality standards of the biodiesel (or blend stocks) as per specification for the particular nation, storage and stabilization are ascribed as the critical steps having immense effect on the successful implementation of biodiesel production and processing. In this review the authors emphasise the important patents developed in the last few years that contribute to mitigate the major technological challenges on biodiesel production and processing.

Experimental study of paddy drying in a vortex chamber

ABSTRACT The intensification of interfacial mass, heat, and momentum transfer makes vortex chambers potentially interesting for the efficient drying of paddy, allowing shorter drying times and/or more compact equipment. The presence of a shell introduces particular challenges. Intraparticle diffusion limitations are strong and may reduce the advantage from intensified interfacial mass and heat transfer and the efficiency of air usage. Furthermore, high shear and normal stresses in the fast rotating particle bed may cause damage to the paddy shell, posing problems for transport and storage. With these specific aspects in mind, the use of vortex chambers for paddy drying is experimentally evaluated.

Discernment of synergism in pyrolysis of biomass blends using thermogravimetric analysis

This study reports pyrolysis kinetics of biomass blends using isoconversional methods, viz. Friedman, FWO and KAS. Blends of three biomasses, viz. saw dust, bamboo dust and rice husk, were used. Extractives and volatiles in biomass and minerals in ash had marked influence on enhancement of reaction kinetics during co-pyrolysis, as indicated by reduction in activation energy and increase in decomposition intensity. Pyrolysis kinetics of saw dust and rice husk accelerated (positive synergy), while that of bamboo dust decelerated after blending (negative synergy). Predominant reaction mechanism of all biomass blends was 3-D diffusion in lower conversion range (α ≤ 0.5), while for α ≥ 0.5 pyrolysis followed random nucleation (or nucleation and growth mechanism). Higher reaction order for pyrolysis of blends of rice husk with saw dust and bamboo dust was attributed to catalytic effect of minerals in ash. Positive ΔH and ΔG was obtained for pyrolysis of all biomass blends.

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Effect of temperature on biogas production from lignocellulosic biomasses

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Kinetic model development for biogas production from cattle dung

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