Meeting ADNOC CoP CO & SO2 Emission Limits, at What Cost? Case Study

Abstract Objective / Scope Over the past several decades, ADNOC has adopted increasingly strict clean air regulations. ADNOC Code of Practice (CoP) stipulates that the Sulphur dioxide (SO2) and carbon monoxide (CO) emissions limits from Sulphur Recovery Units (SRU) (categorized as material producing industry) is restricted to 2000 mg/Nm3 (700 ppmv) and 500 mg/Nm3 (400 ppmv) respectively. GASCO Habshan plant existing SRUs are not designed to meet the current ADNOC CoP emissions requirements. This paper explores all possible options for SO2 and CO emission reduction from Habshan complex SRUs along with cost associated with each option. Methods/Procedure Habshan Complex SRU's Licensors (B&V and Jacobs) and an independent third party consultant were approached to identify the all possible options for SO2 and CO emission reduction. Results, Observations and Conclusions Sulphur Recovery Efficiency (SRE) of above 99.5% is required to achieve SO2 emission of 2000 mg/Nm3 (700 ppmv). This can be achieved only by installation of either Amine based TGTU or Caustic Scrubbing Unit. Estimated Capital Cost for installation of such units is approx. US$ 230 MM for all the SRU's in Habshan i.e. U-52/53/54/57/58/59/152/153 (except U-50/51). Also, as sulphur recovery efficiency increases, the energy required to remove each additional kilogram of sulphur escalates. As energy consumption increases, so too do CO2 emissions, which is an undesirable outcome. Similarly, CO emission levels can be achieved by 1) Operating the incinerator at higher temperature or 2) by Installation of hydrogenation reactor upstream of incinerator for tail gas treatment or 3) by Incinerator modification/replacement. Operating Incinerator at higher temperature will lead to increase in fuel gas consumption and consequently increased CO2 release from stack. Estimated increase in operating cost for incinerator operation at Higher Temperature is approx. US$ 3 MM/yr (at current capacity). Installation of Hydrogenation rector will incur significant capital cost. Estimated Capital Cost for installation of hydrogenation reactor is approx. US$ 45 MM for all the SRU's in Habshan i.e. U-52/53/54/57/58/59/152/153 (except U-50/51). Incinerator modification / replacement will cost approx. US$ 4-5 MM for each incinerator. While endeavoring for lower SO2 and CO emissions may be beneficial from environmental point of view, it does not come free of cost. In fact, it comes with substantial increase in cost. This paper explores all possible options for SO2 and CO emission reduction from Habshan complex SRUs along with cost associated with each option. It also investigates energy consumption and associated CO2 footprint with each option.