Characterization of Sludge Deposits from Refineries and Gas Plants: Prerequisite Results Requirements to Facilitate Chemical Cleaning of the Particular Equipment

Abstract

In this paper, the method developed by the authors to separate the inorganic materials from the hydrocarbon of the sludge deposits, which is fast and can accurately identify very small quantities of inorganic materials, has been extended to characterize the 12 types of sludge samples collected from (a) a regeneration overhead acid gas condenser, (b) water draw-off pump’s suction strainer in a gas plant, and (c) condenser, inside vessels of inlet head, and head coiler tube equipment at gas plants. The results revealed that the major phases are (a) iron sulfide corrosion products with the hydrocarbon type of mixture of diesel and lube oil for a condenser and (b) carbonate scale in the form of calcium carbonate with the hydrocarbon type of lubricant oil for sludge deposits from a suction strainer for pumps, and drilling mud in the form of barium sulfate with no organic hydrocarbon or polymer for sludge samples from a water recycling pump. Moreover, the major phases for inorganic materials built up in a condenser, inside the vessel’s inlet head, and the head coiler tube revealed that iron oxide corrosion products are found in the steam drum, and iron sulfate corrosion products are built up in the condenser. The presence of dissolved oxygen in the boiler feed water is indicated by a high wt% of iron oxide corrosion product in the form of magnetite (Fe3O4), which appeared in the inorganic materials built up in the condenser steam drum. Knowing accurately which phases and their wt% were involved in the inorganic materials can guide the field engineers to facilitate efficient cleaning of the equipment by drawing up the right procedures and taking preventive action to stop the generation of those particular sludge deposits.