BIOCHAR PRODUCTION

Biochar is a porous carbonaceous solid material with a high degree of aromatization and strong ant decomposition ability that is produced by the decomposition of biomass from plant or animal waste under limited oxygen conditions. It has received much attention during the last few years for its potential applications in various agronomic and industrial sectors. Biochars have a tremendous range of physical and chemical properties, which greatly affect their wide applications. Recent evidence suggests that the feedstock and the method by which the biochar is produced has a significant impact on biochar characteristics, including concentrations of elemental constituents, density, porosity, and pH, which collectively impact the ability of the biochar for various applications. Inagriculture, it is used to upgrade the soil quality. It slows down the rate of decomposition ofnutrients from the soil and hence, enhances the soil quality. In different industries, it is used in waste treatment to remove organic contaminants, heavy metals and different kinds of dyes and pigments from textile industries. In power generation, biochar can be used as a fuel because biochar contains a high carbon percentage in it which cans beused as fuel.
Biomass has been found to be a very potential source of renewable energy materials and chemicals. The main sources of biomass as a raw material include agricultural residues, algal biomass, forest residues, manures, activated sludge, energy crops, digestate etc. Biomass may be converted into such high-value products using a number of physical, thermo chemical and biochemical processes. Biochar is produced by thermo chemical conversions, such as pyrolysis, gasification, torrefaction, and hydrothermal carbonization of carbonaceous biomass, such as agricultural residues, algal biomass, forest residues, manures, activated sludge, energy crops, digestate etc. at high temperature (300–900°C) and under O2-limiting conditions. The physical, chemical and mechanical properties of biochars depend on the feedstock type and pyrolysis operating conditions. The selection of a specific type of feedstock is to a great extent determined by the availability of this material in the region where the biochar is likely to be produced, as this reduces the cost of transport while decreasing the carbon footprint of the biochar technology. Production of the biochar from the biomass does not only depend upon the technique which is employed to produce but it is also a function of the process parameters involved in the production also. Studies on the biomass pyrolysis in the recent past have revealed that the production of the biochar depends upon several factors such as type of biomass, moisture content, and particle size, reaction conditions (reaction temperature, reaction time, heating rate) and surrounding environment (carrier gas type, flow rate of carrier gas) and other factors (catalyst, reactor type).
Biochar is a carbon rich highly porous substance obtained after pyrolysis of organic biomass. Production of biochar is a sustainable option for waste and disease management. It contains 50% of the original carbon which is highly recalcitrant in nature; therefore its production helps in carbon sequestration by locking the carbon present in the plant biomass. The elemental composition and structural configuration of biochar is strongly correlated with temperature, heating rate and residence time maintained during its production. Along with the biochar some amount of bio-oil and gases are also produced which can be used for generation of energy and various chemicals. Soil pH and electrical conductivity (EC) increase in soil incorporated with biochar which may be due to the presence of ash residue that is dominated by carbonates of alkali and alkaline earth metals, and some amount of silica, heavy metals and organic and inorganic nitrogen. With its large surface area biochar helps in increasing water holding capacity, cation exchange capacity (CEC), microbial activity (act as its habitat) and also reduces leaching of nutrient by providing nutrient binding sites. This reduces the total fertilizer requirement of biochar-amended soil and thereby reduces environmental pollution caused by leaching of inorganic fertiliser. It also plays a vital role in increasing crop productivity. Apart from improving soil quality biochar provides various other benefits such as mitigation of greenhouse gases (e.g. CH4, N2O and CO2), decrease in dissipation rate of herbicide in soil, used as a building material, cleansing agent in cosmetic industry, waste water treatment and food industry. Due to large availability of biomass resources, India has great potential towards production of biochar.
Biochar is a carbon rich charcoal that is formed by the pyrolysis (thermal decomposition) of organic biomass or agricultural residues which is used as soil amendment. It is composed of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), sulphur (S) and ash in different proportions. It is mainly used to improve soil nutrient content and to sequester carbon from the environment. It’s highly porous structure makes it attractive option for soil amendment as it improves water holding capacity of the soil by increasing the total surface area of the soil.