Mass Transfer in Hollow Fiber Supported Liquid Membrane for As and Hg Removal from Produced Water in Upstream Petroleum Operation in the Gulf of Thailand

Abstract

This chapter describes the merits of using hollow fiber supported liquid membrane (HFSLM), one of liquid membranes in supported structures, and the step-by-step mass transfer in removing arsenic (As) and mercury (Hg) ions from produced water in upstream petroleum operation from the Gulf of Thailand. Apart from the necessary fundamentals, the contents comply existing information and data based on our up-to-date publications in journals. Arsenic (As) and mercury (Hg) are naturally trace components in petroleum reservoir. In certain Gulf of Thailand fields, the concentration levels vary widely and Hg, in particular, is drawing local statutory attention since its concentration is found typically higher than those found in the rest of the global petroleum production areas. A number of hypotheses have suggested the origin of As and Hg in the petroleum reservoirs laid underneath the Gulf. But one common fact agrees that mercury predominantly presents in an elemental form Hg(0) with the rest in an inorganic form (HgCl2), organic forms (CH3HgCH3 and C2H5HgC2H5) and an organo-ionic form (ClHgCH3). For arsenic, it presents as As(III) and As(V) (Korte & Fernando, 1991). The As(III) is normally in the form of H3AsO3 whereas As(V) is in either H2AsO4or HAsO42-. Arsenic and mercury are grouped in the most hazardous metals since arsenic compounds are carcinogens, both severe acute and chronic toxicity, while mercury can evaporate in soil or water; short-term exposure results in kidney damage; and a lifetime of exposure can lead to impairments in neurological functioning (U.S. EPA, 1984). In the Gulf of Thailand, petroleum development and upstream production have been very active recently following an increasing domestic energy demand and a soaring global oil price. Accordingly, numbers of leading and national oil companies have been gathering in the Gulf for an interest of petroleum exploration and production. Figure (1) presents 2009 updated petroleum concessionaire map in the Gulf of Thailand where total gross production