Experimental and numerical approach to improve the performance of a small chp wood gasification plant

Currently, biomass gasification for small scale combined heat and power (CHP) plants (< 500 kWe) is attracting increasing interest as a way to provide remote and/or rural districts with electrical-thermal power, also creating a sustainable economy on the territory. In this context, downdraft gasification technology, coupled with reciprocating internal combustion engine (RICE), is characterized by higher conversion efficiencies in comparison with other technologies. However, the exploitation of a syngas from biomass gasification into a RICE is not easy, due to the presence of contaminants and to the composition that mainly affects engine outputs. At the same time, gasification operative parameters, such as equivalence ratio (ER), biomass moisture content, gasification air temperature (GAT), etc., have a significant influence on gas production and composition and, consequently, on its heating value. Therefore, it is not immediate to find the best setting to maximize, at the same time, gasifier and RICE performances.The present work shows the application of an experimental and numerical methodology aimed to study how the gasifier setting influences RICE performances. Using a kinetic model, implemented Aspen Plus ® commercial platform, the syngas production and composition of a wood downdraft gasifier has been predicted varying ER and GAT. After that, the influence of syngas composition on RICE performances has been analysed using the dedicated AVL Boost® commercial code. Both models have been previously tuned using experimental data obtained from a commercial scale wood gasification CHP plant.