The present study focuses on the improvement of gas quality by gasification of raw and cashew shells heat treatment by roasting and carbonization. The gasifier is a fixed-bed co-current batch mode, with a throat. It has a thermal power of around 30 kW. It meets the need for low electrical power of the order of 10 kWe. It has a double wall with a height of 153 cm and a diameter of 50 cm, and a double air injection. Improving the quality of the gas, consisting of reducing the balsam content contained in the raw shells, as well as the improvement of the physico-chemical characteristics of the shells. And this is done through the roasting and carbonization process. The tests carried out aim to evaluate the energy performance of the gasifier and analyze the gas composition resulting from the gasification of raw, roasted and carbonized cashew shells. The parameters studied are the energy efficiency of the gasifier and the energy capacity of the gas. The study showed that the energy yields of the gasifier by gasification of raw, roasted and carbonized hulls are respectively 47.5%; 28.32% and 31.48%. The specific production rate of the gas is 28.3; 132.76 and 155.32 kg/m2∙h respectively for raw, roasted and charred hulls. The gasification times of raw, roasted and charred hulls are 224.33 respectively; 201 and 211 minutes. The composition of syngas shows that the gas produced from cashew shells is low in energy. Indeed, the PCI of gas from the raw, roasted and carbonized hulls is 3.1, respectively; 2.1 and 2.87 MJ/N∙m3.

Cashew Nuts Shells, Gasification, Roasting, Carbonization, Energy Efficiency