A gasifier can convert 1 kg of wood 195 MJkg into 15 m3 of s

A gasifier can convert 1 kg of wood (19.5 MJ/kg) into 1.5 m3 of syngas (5.2 MJ/m3). If we define energy conversion efficiency as the ratio of syngas energy to biomass energy, what is the energy conversion efficiency of wood to syngas?

Solution

Any efficiency is simply : output power / input power

Output power = 5.2*1.5 = 7.8 Mj

Input power = 19.5 * 1 = 19.5 Mj

Energy efficiency = 7.8/19.5 = 0.4 = 40%