Removal of hydrogen sulfide from landfill gas at full scale landfill (Odayeri): A research study

Landfill gas is produced by the landfilling of solid waste and it can be used energy production. Landfill gas contains environmentally harmful trace components such as siloxanes and Hydrogen Sulfide (H2S), Volatile Organic Compounds (VOCs) and they are caused by problems in the energy recovery. Gas engines performances are affected by impurities in the landfill gas and these impurities are affect the economic of energy recovery. Gas engines equipments can wear out and can be changed earlier than planned, depending on the type and amount of impurities in the gas. These impurities are increase maintenance costs and production losses due to maintenance of gas engines and all of these increase operating costs. Because of these reasons it is necessary to remove the H2S in landfill gas in order to prevent harmful effects. In the literature, the permissible limit concentration of H2S in the internal combustion engine is given as 100 ppm. A pilot scale H2S removal system was designed and established at Ortadoğu Energy Odayeri Power Plant. For this purpose, the system is designed by using 225 mm diameter HDPE pipe. Three different hydrogen sulphide adsorptive materials (commercial activated carbon, iron (III) hydroxide and iron (III) containing sludge) was used at pilot scale system and measurement was made three times a day. After that, hydrogen sulfide removal efficiency of these materials were examined and design criterias and performance parameters for the all materials were determined. For this purpose, adsorption isotherms has been prepared with using MATLAB R2013a program with nonlinear regression and adsorption coefficients were founded. Accordingly, iron (III) containing sludge has the highest maximum saturation capacity (874.8 mg/g). On the other hand, iron (III) hydroxide solution has maximum adsorption capacity of 737.8 mg/g. Iron (III) oxide solution's capacity lower than iron (III) containing sludge because of the pH paremeter was not controlled. In general, iron (III) solutions have higher capacity than activated carbon. The active carbon with working raw gas is determined to be at a higher capacity than dehumidified gas. At the iron (III) solutions removal efficiency can be fixed by making the regeneration of the removal efficiency of the solution than activated carbon. Iron (III) solution's experimental data was found to comply with the first order kinetics and kinetic parameters are determined. Accordingly, iron (III) hydroxide absorption rate constant is higher than the iron (III) containing sludge. So, iron (III) hydroxide's capacity is greater than iron (III) containing sludge. Iron (III) containing sludge can be used as an alternative method for H2S removal from landfill gas according to cost factors such as landfill gas to energy plant capacity and proximity between the drinking water treatment plant and landfill gas to energy plant. Keywords: hydrogen sulfide, landfill gas, activated carbon, iron (III) hydroxide, drinking water treatment sludge, adsorption, absorption