ORIGINAL ARTICLE Development and performance evaluation of batch type biomass pyrolyser for agricultural residue J. M. Makavana 1 & S. V. Kalaiya 1 & M. S. Dulawat 1 & P. N. Sarsavadiya 1 & P. M. Chauhan 1 Received: 2 June 2020 /Revised: 7 October 2020 /Accepted: 22 October 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Cotton stalks and other agricultural crop residues are available in plenty and are very potential as an energy source in Saurashtra region. These residues are sometimes, burnt in the field itself which creates an adverse condition to soil health. The objective of this research study was to develop a pyrolyser, methodology, to identify the physical-chemical-thermal properties and elemental analysis of bio-char. A small capacity (5 kg/batch) biomass pyrolyser was designed and developed for making bio-char from the shredded cotton stalk as feed stalk. Pyrolysis at various experimental temperatures 200, 300, 400 and 500 °C and residence time 60, 120, 180 and 240 min carried out for optimal parameter estimation. The quality of bio-char obtained at 500 °C temperature and 240 min is best out of the all experimental parameters. The calorific value of bio-char measured 33.89 MJ/kg and contents of nitrogen 1.56%, carbon 79.30% with C/N ratio 50.83. Conversion of agricultural residues into bio-char, bio-oil and pyro-gas will be a good option to be used as fuel and a safe sustainable soil amendment of bio-char to improve fertility. Keywords Cotton stalk . Agricultural residue . Biomass . Pyrolyser . Bio-char 1 Introduction Various types of biomass available such as agricultural resi- dues, forestry residues, municipal waste and city products can be used to convert into various forms of energy by direct combustion to modern gasification and pyrolysis. Biomass is available in large quantities, renewable and clean as it has zero carbon emission, low sulphur, nitrogen and metal content [1]. Pyrolysis technologies can be differentiated by the reaction time of the pyrolysis material (slow, intermediate and fast pyrolysis processes) and the heating method [8]. Bio-char is a charcoal, made from biomass by pyrolysis process which can be used as fuel. Thermal degradation of lignin and hemicellulose results in a considerable mass loss in the form of volatiles, leaving behind a rigid amorphous carbon matrix which is referred as bio-char. Depending on the operating condition, pyrolysis can be classified into three main categories: conventional, fast and flash pyrolysis. These differ in process temperature, heating rate, solid residence time, biomass particle size, etc., the product yield of char vary from 12 to 35% [4]. The total carbon recovery in the bio-char ranged from 27 to 37 % over the feedstock. Bio-char is a value-added product, which can be used for many purposes. It is highly carbonaceous and hence contains high energy con- tent, comparable to high rank coals. The primary use has been as fuel (charcoal) for heat production for cooking and heating. The addition of bio-char influences the physical properties of the soil by altering the structure, porosity, pore size distri- bution, density and packing which has the potential to im- prove plant growth. Also, bio-char can reduce soil acidity, improve soil cation exchange capacity (CEC), water holding capacity and improve the environment for beneficial microbes [7]. Less fertiliser needed, when added to soil, bio-char im- proves plant growth and crop yields while reducing the total fertiliser required. Nitrous oxide (N 2 O), a greenhouse gas, released from certain fertilisers is 310 times more potent than carbon dioxide (CO 2 ). Bio-char conditioned soil reduce N 2 O off-gassing by 50–80% [11]. Supplementary Information The online version contains supplementary material available at https://doi.org/10.1007/s13399-020- 01105-1. * M. S. Dulawat msdulawat@gmail.com 1 Department of Renewable Energy Engineering, College of Agricultural Engineering and Technology, Junagadh Agricultural University, Junagadh, Gujarat 362001, India Biomass Conversion and Biorefinery https://doi.org/10.1007/s13399-020-01105-1