Rupam Kataki

Fuelwood characteristics of some indigenous woody species of north-east India

Abstract Wood energy is identified as the major source of energy in rural India and this has necessitated the identification of suitable tree species that can be included in energy plantation programme. As a preliminary to a more detailed future study of wood energy plantation, four indigenous perennial tree species, viz. Albizzia lucida , Syzygium fruticosum , Pterospermum lanceaefolium and Premna bengalensis growing in their natural habitat of north-east India were collected for fuelwood characterization studies. Various physico-chemical properties, viz. moisture and ash content, density, solubility in cold water, hot water and alkali, cellulose, holocellulose, lignin and extractive contents of different parts of these species were determined on ash-free dry weight and extractive-free dry weight basis to find out relationship, if any, between ash and extractive content with the calorific value. In all the species, leaf component contained the highest calorific value presumably because of the presence of extractives in higher amount, followed by heartwood. Elimination of ash from the plant parts increased calorific value while extractive-free materials declined in net caloric content in all plant parts, indicating a possible relationship of these two parameters with the heat of combustion. This study concludes that A. lucida , S. fruticosum and P. lanceaefolium have better fuelwood properties and can be considered for inclusion in the energy plantation programme of north-east India.

Fuelwood characteristics of indigenous tree species of north-east India

Abstract Fuelwood characteristics viz. moisture content, ash, silica, carbon, nitrogen, volatile matter, density and calorific value of 35 indigenous tree species of the age group of 10–15 years growing in their natural habitat in north-eastern region of India were determined and Fuel Value Index (FVI) of each of them was calculated. From the experimental data and the FVIs, it is found that Acacia nilotica, Acacia auriculiformis, Albizzia lebbeck, Albizzia procera, Pinus kesiya and Elaeognus umbellata possess better fuelwood characteristics and they may be considered for inclusion in energy plantation programme in the region.

Perennial grass (Arundo donax L.) as a feedstock for thermo-chemical conversion to energy and materials

In the present study, perennial grass species Arundo donax L. was pyrolysed in a fixed-bed reactor and characterization was performed for the liquid and the solid products. The effect of process parameters such as temperature (350-650 °C), heating rate (10 °C and 40 °C min(-1)) and sweeping gas flow rate (50-250 ml min(-1)) was also investigated. Maximum bio-oil yield of ∼ 26% was observed at 500 °C for the heating rate of 40 °C min(-1). Chemical composition of the bio-oil was analysed through NMR, FTIR and GC-MS. The biochar was characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy along with elemental analysis (CHN). The biochar produced as a co-product of A. donax pyrolysis can be a potential soil amendment with multiple benefits including increased soil fertility and C-sequestration. Current investigation suggests suitability of A. donax as a potential feedstock for exploitation of energy and biomaterials through pyrolytic route.

Pyrolysis of Mesua ferrea and Pongamia glabra seed cover: Characterization of bio-oil and its sub-fractions

In the present study, pyrolysis of Mesua ferrea seed cover (MFSC) and Pongamia glabra seed cover (PGSC) was performed to investigate the characteristics of bio-oil and its sub fractions. In a fixed bed reactor, the effect of temperature (range of 350-650 °C) on product yield and quality of solid product were monitored. The maximum bio-oil yield of 28.5 wt.% and 29.6 wt.% for PGSC and MFSC respectively was obtained at 550 °C at heating rate of 40 °C/min. The chemical composition of bio-oil and its sub fractions were investigated using FTIR and (1)H NMR. GC-MS was performed for both PGSC and MFSC bio-oils and their corresponding n-hexane fractions. The results showed that bio-oil from the feedstocks and its sub-fractions might be a potential source of renewable fuel and value added chemicals.

Thermogravimetric and decomposition kinetic studies of Mesua ferrea L. deoiled cake

The present study aims to explore the physico-chemical properties of Mesua ferrea L. (Iron wood tree) deoiled cake (MFDC) and decomposition parameters for thermochemical methods of conversion. The physico-chemical characteristics of MFDC were investigated by bomb calorimetry, TG/DTA (10, 20 and 40°C min(-1)), elemental analysis (CHN) and FTIR spectroscopy. The proximate composition was calculated using standard ASTM methodology. The temperature profile, activation energy (E), pre-exponential factor (A) and reaction order (n) for the active pyrolysis zone of the species under investigation have been provided for the respective heating rates using Arrhenius, Coats-Redfern, Flynn-Wall-Ozawa (FWO) and Global independent reactions model. The current investigation suggests that within the realm of existing biomass conversion technologies, MFDC can be used as a feedstock for thermochemical conversion.

Characterization of liquid and solid product from pyrolysis of Pongamia glabra deoiled cake.

In the present study, a new feedstock, Pongamia glabra deoiled cake (PGDC), is reported for pyrolysis. Experiments were conducted in a laboratory scale fixed-bed pyrolyzer at temperatures ranging from 350 to 600°C with varying heating rates of 10, 20, 40°C/min in nitrogen atmosphere. The highest liquid yield of 30.60% was observed at 500°C with heating rate of 40°Cmin(-1). The biochar obtained had a porous structure and was characterized by powder X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy along with elemental analysis. The representative bio-oil sample was characterized by CHN analyzer, GC-MS, NMR and FTIR spectroscopy. The bio-oil has a calorific value of 28.19MJ/kg and contains a higher amount of aliphatic compounds. The present investigation suggests that within the realm of biomass energy conversion technologies the PGDC can be used as a feedstock for pyrolysis conversion, thereby serving the demand of second generation biofuels.

Production of Solid Fuel from Ipomoea carnea Wood

Abstract Ipomoea carnea woody stems were pyrolyzed in a laboratory-scale reactor in the temperatures ranging from 350° to 600°C and at constant heating rate of 5°C/min. Yield, density, ash content, volatile matter, fixed carbon content and calorific value of the charcoal samples produced were evaluated. Charcoal yield ranged from 24.23% to 37.89 wt% and calorific value varied from 17.29 to 33.47 MJ/Kg. Conversion of charcoal fines to solid fuel improved combustion quality. Mass balance experiments of pyrolytic decomposition products of I. carnea yielded much higher percentages of non-condensable liquid (59.2–61.8 wt%) as compared to those of tar (4.2–4.8 wt%) and gas (7.3–8.2 wt%) fractions.

Biosorption of Co (II) from aqueous solution using algal biochar: Kinetics and isotherm studies

The present investigation deals with the utilization of biochar derived from the pyrolysis of microalgae Scenedesmus dimorphus as an adsorbent for the removal of cobalt (II) ion (Co) from aqueous solution. A series of experiments were conducted in a batch system to evaluate the performance of the biochar for Co removal. The effect of contact time on adsorption of Co (II) onto surface of the biochar was investigated. The equilibrium sorption data were analyzed by using Langmuir, Freundlich, Temkin, Harkins-Jura and Dubinin-Radushkevich (D-R) isotherms and were found to be adequate in describing the Co adsorption onto the biochar. Equilibrium data were well fitted for Freundlich, Temkin and D-R isotherms. The kinetic study of Co (II) adsorption on microalgae biochar were described by applying pseudo-first-order and pseudo-second-order rate equations. The surface of adsorbent before and after the removal of Co (II) was characterized by using SEM, EDX and XRD analysis.

Pyrolysis of Some Indigenous Tree Species of Northeast India: Effect of Pyrolysis Temperature and Heating Rate on the Products Yield and Char Quality

Abstract Seven indigenous tree species of northeast India were pyrolyzed at temperatures ranging from 300°C–800°C with two different heating rates, 3°C/min and 20°C/min, and the effect of heating temperature and heating rate on the products yield and char quality were analyzed and discussed. Among all the species, E. acuminata, M. bombycina and Q. griffithii were found to yield higher percentages of char with better quality, whereas A. lucida yielded the highest percentage of tar.

Effect of torrefaction on yield and quality of pyrolytic products of arecanut husk: An agro-processing wastes

In the present study, arecanut husk, an agro-processing waste of areca plam industry highly prevalent in the north-eastern region of India, was investigated for its suitability as a prospective bioenergy feedstock for thermo-chemical conversion. Pretreatment of areca husk using torrefaction was performed in a fixed bed reactor with varying reaction temperature (200, 225, 250 and 275°C). The torrefied areca husk was subsequently pyrolyzed from temperature range of 300-600°C with heating rate of 40°C/min to obtain biooil and biochar. The torrefied areca husk, pyrolysis products were characterized by using different techniques. The energy and mass yield of torrefied biomass were found to be decreased with an increase in the torrefaction temperature. Further, biochar were found to be effective in removal of As (V) from aqueous solutions but efficiency of removal was better in case of torrefied biochar. Chemical composition of bio-oil is also influenced by torrefaction process.