Design and Performance Analysis of A Biomass Pyro-Chulha for Clean Cooking and Biochar Production

The traditional practice of open burning of agricultural waste along with the use of traditional cooking stoves in many rural areas of India have contributed to several environmental problems such as the emission of greenhouse gases, air pollution, and soil degradation. In this study, we present the design and simulation-based analysis of a dual function cookstove – the Pyro-Chulha which integrates clean cooking and biochar production through pyrolysis. The design of the stove incorporates a lower combustion chamber and an upper pyrolysis chamber both of which are naturally draft driven and thermally insulated. A producer gas reinjection system is used to enhance the volatile gas pyrolysis combustion. Combustion enhancement reduces emissions and increases efficiency. The design was evaluated using thermodynamic calculations and computational fluid dynamics (CFD) to evaluate heat transfer, gas flow, and temperature distribution within the device. Results from the simulation showed that the traditional cookstove emissions of particulate matter and carbon emissions were significantly surpassed with a lower emission of 150 µg/m³ and 50 ppm, alongside a combustion efficiency of 90% and heat transfer efficiency of 85%. Due to passive heat transfer and the insulation present in the pyrolysis chamber, an estimation of 600-650 K is reached. This enables production of around 0.2 kg/hr of biochar which is ideal for soil enhancement due to its ~70% carbon content. The Pyro-Chulha provides an integrated approach to tackling the issues of clean cooking, the utilization of waste biomass, and sustainable soil management. It does so in a scalable and climate-resilient manner, without incurring significant costs. This paper suggests deployment into the field as well as long-term studies to ascertain real-world performance and agronomic impact in rural settings.