During the past several decades, the Abu Dhabi National Oil Company (ADNOC) has adopted increasingly strict clean-air regulations. ADNOC’s code of practice stipulates that the sulfur dioxide (SO2) and carbon monoxide (CO) emissions from sulfur-recovery units (SRUs) are restricted to 700 and 400 ppmv, respectively.
ADNOC’s Habshan gas-processing plant’s existing SRUs are not designed to meet the ADNOC’s current emissions requirements. This paper explores all possible options for SO2 and CO emission reduction from Habshan complex SRUs along with the cost associated with each option.
The Habshan SRU’s licensors and an independent third-party consultant were approached to identify all possible options for SO2 and CO emission reduction.
Sulfur-recovery efficiency (SRE) of greater than 99.5% is required to achieve SO2 emission of 700 ppmv. This can be achieved only by installing either an amine-based tail-gas-treating unit or a caustic scrubbing unit. The estimated cost for installation of such units is approximately $ 230 million for all the SRU’s in Habshan. Also, as SRE increases, so does the energy required to remove each additional kilogram of sulfur. As energy consumption increases, so, too, do carbon dioxide (CO2) emissions, which is an undesirable outcome.
Similarly, the desired CO emission levels can be achieved by operating the incinerator at a higher temperature, by installing a of hydrogenation reactor upstream of the incinerator for tail-gas treatment, or by modifying or replacing the incinerator.
Operating the incinerator at a higher temperature will lead to an increase in fuel-gas consumption and, consequently, an increase in CO2 released from stack. The estimated increase in operating cost for operating the incinerator at a higher temperature is approximately $ 3 million/year at current capacity.
The installation of hydrogenation reactors will incur significant cost. Estimated cost for installation of hydrogenation reactors is approximately $ 45 million for all the SRU’s in Habshan.
Incinerator modification or replacement will cost approximately $4 million to 5 million for each incinerator.
While working to lower SO2 and CO emissions is beneficial from an environmental point of view, it is not free. In fact, it comes with substantial increase in cost. This paper explores possible options for SO2 and CO emission reduction from Habshan complex SRUs along with costs associated with each option. It also investigates energy consumption and associated CO2 footprint with each option.
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