All Sulphur recovery units (SRU’s) in the Province of Alberta employ thermal incinerators to treat the tail gas effluent from the SRU’s prior to emitting the waste gas to the atmosphere. The purpose of the thermal incinerator is to facilitate the oxidation of all of the common reduced Sulphur compounds (H2S, COS, CS2 and Sulphur vapour) to SO2 prior to release to the atmosphere.
Since 1980, many thermal incinerators in the province have conducted “incinerator optimization” studies in order to identify opportunities to reduce fuel gas consumption by reducing the operating temperature of these systems while continuing to meet the environmental emission requirements of the plant. The “traditional” approach to these optimization studies was based primarily on a combined thermodynamic and kinetic incinerator model (INCWRD), which has been in use since ca. 1980.
The original incinerator model was based on a limited set of data which had been gathered in the late 1970’s. This work expanded the test set to include plant test data gathered from 1980 to 2004 which allowed for more accurate and representative kinetic correlations for modelling the oxidation efficiency of TRS compounds in these thermal incinerators.
The results from this study have allowed for the compilation of updated correlations for the oxidation of H2S, COS, CS2 and H2. Also, this work allowed for the derivation of an kinetic correlation for the oxidation of CO for the first time. The use of these correlations in the update incinerator simulation model will allow for more accurate and effective calculations to support new incinerator optimization programs.
Additionally, this study investigated the use of new incinerator technology to realize new opportunities for incinerator optimization. In past works, these incinerators were optimized only for incinerator temperature, essentially a one dimensional optimization approach. These new concepts allow for a “multi-dimensional” optimization approach which includes the use of better system mixing (turbulence) and more system residence time as well as investigating methods for reducing the amount of the undesired pollutants in the SRU waste gas. The case studies completed in this work suggest that these approaches will identify more and larger opportunities for optimization of thermal incinerators in order to reduce fuel gas consumption and CO2 emissions.