ELIMINATION OF HYDROGEN SULFIDE FROM SOUR GAS IN CSTR BIOREACTOR USING NATIVE ISOLATED STRAIN OF SULFUR OXIDIZING BACTERIA

Abstract

Biodesulfurization of sour gas has been carried out in a continuous stirred tank bioreactor with culture volume of 3.5 L. Pure culture of sulfur oxidized bacteria was isolated from Ramsar (Iran) hot spring. Bioreactor performance was evaluated in terms of elimination capacity (EC, mg/L.h) and removal efficiency (RE, %). The highest RE% of H2S at high concentration of sour gas was determined to be 99%. The effect of agitation rate on the removal efficiency was evaluated at four different gas flow rates ranged in 0.5 to 2mL/min. The optimum gas flow rate was achieved 0.5mL/min. In addition, the achieved optimal dilution rate and cell productivity were 0.01 1/h and 0.018 g/L/h, respectively. Furthermore, the limitation of dilution rates in the bioreactor and wash-out phenomena were considered. The biodegradation kinetic values obtained from Michaelis Menten model. The proposed model was satisfactorily fitted with the experimental data with three agitation rates in the bioreactor operation for the purpose of biodesulfurization of natural gas.