The Effect of Potassium Hydroxide (KOH) Concentration, Temperature and Resistance Time on Quality of Producer Gas

Biomass gasification is the thermochemical conversion of biomass materials into a producer gas. The producer gas is a mixture of CO, CO₂, CH₄, H₂, N₂ and water vapour. During gasification, impurities, such as tars, particulate matters, NH₃, H₂S, HCl and SO₂, are unavoidably produced and generally sustained in the producer gas. Tars cause severe problems in downstream applications of the gas such as blocking of the pipes, gas engines or turbines due to its condensable characteristics. Thus, results decrease in efficiency and increase the process cost. Hence, it is indispensable to remove tar as well as particulates from the producer gas to achieve better efficiencies. There are several technologies for removal of tars; however, everyone have some limitations and these were too expensive from the techno-economical point of view. In the present work, dosing of alkali hydroxide (KOH) for cleaning of producer gas was performed. The producer gas was passed through different concentrations of KOH solution to achieve the gas of best quality. The optimised concentration was further studied to enhance its cleaning efficiency by maintaining some temperature of KOH solution and residence time of the producer gas with KOH solution. The percentage found of the removal efficiency of tar and suspended particulate matter at higher temperature (70°C) was 76.19%. Hence, it was concluded that the cleaning efficiency of the producer gas enhances by increasing the temperature of optimised concentration of dosing solution. The significant feature of this technology is that it is economically feasible.