The objective of this paper is computational investigation of the carbon black production through thermal decomposition of waste gases containing CH4 and H2S, without requiring a H2S separation process. The chemical reaction model, which involves solid carbon, sulfur compounds and precursor species for formation carbon black, based on an assumed Probability Density Function (PDF) parameterized by the mean and variance of mixture fraction and β-PDF shape. The effects of feedstock mass flow rate and reactor temperature on carbon black, S2 , SO2 ,COS and CS2 formation are investigated. The results show that the major factor influencing CH4 and H2S conversions is reactor temperature. For temperatures higher than1100oK , the reactor CH4 conversion reaches 100%, whilst H2S conversion increases for temperatures higher than 1300oK . The results reveal that at any temperature, H2S conversion is less than that of CH4. The results also show that in the production of carbon black from subquality natural gas, the formation of carbon monoxide which is occurring in parallel, play a very significant role. For lower values of feedstock flow rate, CH4 mostly burns to CO and consequently, the production of carbon black is low.

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