Process, method, and system for removing heavy metals from fluids

摘要

Trace element levels of mercury in crude oil are reduced by first passing the crude oil through a filtration device to generate filtered crude having a reduced concentration of mercury and a reject stream having a concentrated mercury level. In one embodiment, the filtration device is back-flushed to generate the reject stream. In another embodiment, the reject stream comprises a portion of the retentate from a cross-flow filter device. The reject stream is treated with an extractive agent selected from tetrakis (hydroxymethyl)phosphonium sulfate; tetrakis(hydroxymethyl) phosphonium chloride; an oxidizing agent; an organic or inorganic sulfidic compound to extract a portion of the mercury into a water phase for subsequent removal. In one embodiment, the extractive agent is a reductant to convert non-volatile mercury into volatile mercury.