Minimization of SO2 Emissions at ADGAS (Das Island, UAE): I- Current vs. Modified Schemes

Abstract

The objective of this work is to explore feasible technologies to minimize SO2 emissions from ADGAS and investigate the impact of implementing such modifications on the ambient air quality at the Island. In order to achieve this, two SO2 emission minimization schemes have been proposed; a Fuel Gas Sweetening (FGS) scheme and a Flue Gas Desulfurization (FGD) scheme.The FGS scheme involves (1) directing most of the H2S in the fuel gas to the Sulfur Recovery Units (SRUs) where it is converted to elemental sulfur. The unconverted H2S will be routed to the SRUs’ incinerators where it is oxidized to SO2, and (2) revamping the UGAs internals (by replacing current packing with an approved higher efficiency packing) in order to produce a sweeter fuel gas. The FGD scheme involves installation of SW-FGD units downstream the SRUs’ incinerators where the SO2 in the flue gas is scrubbed by the plant spent seawater in a dedicated packed bed absorber and converting it to harmless sulfate ions (natural constituents of the seawater) that will be safely disposed to the sea. The FGS scheme is expected to reduce the H2S content in the fuel gas by 94% and result in decreasing the total SO2 emissions due to fuel gas usage by 98%. The FGD scheme is expected to reduce the SO2 emissions due to incomplete sulfur recovery in the SRUs by 99.5%. Implementation of both schemes is expected to reduce the total SO2 emissions by 77%. Most of the remaining SO2 emissions (23%) are due to the continuous flaring of the flash gas in the plant. In Part II of this work, the BREEZE AERMOD Pro Software is used to predict the SO2 Ground Level Concentration (GLC) for the current and modified SO2 minimization schemes. Compliance with the country limits and challenge with future regulatory standards have been examined.