Use of gasification char for hot gas filtration in micro-scale power plants

Char is a carbonaceous gasification by-product often used as soil amendment due to its high porosity and recalcitrant structure. Porosity is a fundamental feature when char is used to adsorb liquids and aerosol. This paper investigates gasification char as filtering medium for producer gas in small-scale gasifiers. Two metallic candle filters filled with about 1 kg of gasification char each were fabricated and tested under different temperature conditions (60, 70 to 80 °C). Char behavior as tar and particulate filter is qualitative and quantitative assessed evaluating tar deposits afterwards the engine governor as well as using the “Tar Sampling Procedure” methodology. Encouraging performance of char candle filters was achieved with a producer gas temperature of 60 °C and with gas-air mixture temperature of 70 °C at the engine manifold. Furthermore pressure drop across the filters was monitored and its influence on the engine maximum power output was evaluated.