Processing Bio-char and Study of Dielectric Behaviour of Castor Plant Biomass

Abstract

In tropical countries a huge amount of plant and trees grows abundantly and their utilisation is not yet being emphasized rather creating environmental hazards. In recent year, few countries have tried for utilisation of biomass to make value added products such as bio-char, bio-fuel and activated carbon etc. Biomass is an effective and eco-friendly alternative source of energy; since it reduces the environmental pollution as well as reduces the net carbon dioxide emissions, is a burning research area. The present piece of work is aimed at making bio-char from castor plant. The plant component such as leaves, stem and wood are selected as 3 specimens for processing bio-char. Chemical treatment and pyrolysis procedure are adopted for making the product. The proximate analysis of the samples is carried out to estimate the fixed carbon and volatile matter etc.The specific heat of the sample is also measured with bomb calorimeter technique, to find its suitability as a substitute for fossil fuel. The specific heat varies between 3448.4 Kcal/kg to 4271.97 Kcal/kg. The dried leaf, stem and the wood of the castor plant were powdered using planetary ball mill. The samples were pyrolysed at 250°C, 350°C, 450°C, 600°C and 900°C at normal atmospheric condition. The chemical treatment of the samples wasmade by adding 5% of stearic acid and sodium hydroxide solutions at room temperature. Then the samples weretaken out and washed thoroughly in running water and stored for further investigation. FTIR analysis of the raw material, chemical treated and pyrolysed samples are carried out to find out stretching,bending and seizing of different bond present (and formed/affected) in the material. The stretching and bonding of C-O-C, C=C stretch of alkanes, presence of O-H vibration stretching, symmetric stretch of CH in aliphatic compounds and the axial deformation of the C-H group have taken place during chemical treatment and pyrolysis. Microstructural studies are carried out using SEM & EDS analysis. The microstructure of the samples is also different depending on the thermal and chemical treatments. In some cases,polygonal grain structure is seen and in some cases needle shaped appearance is observed. X-Ray diffractograms are taken on the samples to find out the phases present and transformed/formed (if), during pyrolysis and chemical treatment. It is observed that,the carbon in organic state is in amorphous form got transformed into crystalline form, during pyrolysis.To find out the high valued utilisation, the dielectric behaviour of the raw and pyrolised stuffs is studied. From the dielectric studies it is found that, these materials can be utilised for capacitor applications at medium frequency range i.e. between 100 Hz to 1 MHz range.