Production and beneficial impact of biochar for environmental application: A review on types of feedstocks, chemical compositions, operating parameters, techno-economic study, and life cycle assessment

Biochar generation from biomass pyrolysis is an appealing and practical technology for storing carbon and lowering the greenhouse gas (GHG) emissions. Carbon recalcitrance in biochar, also known as biochar stability, is an important feature that determines carbon sequestration capacity. Further, the stability of biochar affects the varying process parameter, which flatters the frontier of biochar study. Also, the properties of biochar substantially alter with the various parameters such as operating constraints, types of feedstock, reactors types, etc. In this review, the stability of biochar is explored in-depth, as well as how and why biomass handling variables such as pyrolysis temperature and reaction residence time, compositions and physicochemical properties impact on it. Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA) of biochar are also highlighted in this review. This review invalidates the failure of current research to give weight to such important concerns in the exposure of TEA and LCA to biochar production. According to this review, relatively high temperatures (400–900 °C), extended residence and holding times, moderate heating rates, certain minerals, and biomass feedstock with a high lignin content and big particle size are desirable for biochar stability. However, the trade-offs between biochar stability and other potential improvements are mediated by constraints. The compromises between the stability of biochar and other possible gains are mediated by obstacles. In addition to carbon nanotubes, capacitors, energy storage devices, and bio-adsorbents, strategies have been developed to promote the use of biochar as a tool to mitigate climate change. The goal of this review is to improve and commercialize biochar technology to fulfill the needs of many industries; it help to the researcher particularly interested in the thermochemical alteration of feeds and the creation of novel pyrolyzer.