SIMULATION OF BIOFILTRATION UNIT FOR H2S REMOVAL

Abstract

Biofiltration is a technology based on the biodegradation of pollutants in airstreams and for odor control. This is accomplished by microorganisms in biofilm formed around porous solids that are placed in packed-bed reactors. A mathematical model is developed to validate the data obtained for steady-state biodegradation of. H2S. The mgdel took into account biodegradation kinetics, the effect of oxygen, and mass transfer from the gas to the biolayer. System is simulated to predict performance of biofilter.The model is solved in the Biofllm first and then along the Biofilter using a computer code in MATLAB. It is proved that Removal efficiencies of greater than 98% can be achieved by parameter analysis for 1 meter length of biofilter by simulation. Simulation is done over all H2S concentration ranges low, mid and high. Modeling and simulation for reactions involving substrate inhibition, effect of excess oxygen and net chemical and biological oxidation are done. It is observed that H2S removal is nearly same, both in the absence of oxygen and in the presence of excess oxygen. Effect of substrate inhibition is clearly shown through simulation. Sensitivity of biofilter performance to Surface Area per unit volume, film thickness and other parameters are studied. . Comparison of different reaction situations in the Biofilm is done. Nearly linear concentration profile along the Biofilter is obtained. Elimination Capacity and removal efficiency are studied for different parameters. Higher stream flow rates increases Elimination capacities with decrease in removal efficiencies. Inlet loadings of around 10-20 g/m3/hr are best for higher removal efficiencies. It is concluded that analysis on inlet concentration of 5 g/m3 for 1 m biofilter given best performance at ALE ratio of 3000 m2 /m3 and film thickness of 2* 104 m. It is concluded that biofilter's performance of removal efficiency greater than 98% is achieved at high residence times and high surface area per unit volume. The Code faced some numerical problems during simulation at low concentrations of H2S. III