Abstract: The flow rate of the absorption medium entering an absorption column and the flow rate of steam into a reboiler associated with a stripping column are controlled in response to the flow rate of a feed stream into the absorption column, the concentration of impurities in the feed stream, and the flow rate of the absorption medium containing the impurity removed from the feedstream into the stripping column in such a manner that the efficiency of the absorption process is optimized. A computer system is utilized to simulate the flow of materials inside the absorption and stripping columns. Feed forward control, based on the simulations, is utilized to maximize the energy efficiency of the absorption/stripping process by reducing the amount of steam required by the stripping process and reducing the energy consumption of the pumping system utilized to return the absorption medium to the absorption column.

Abstract: A process is provided in which a gas, particularly a sulfur-free natural gas, that contains mercury is contacted with an amount of hydrogen sulfide in excess of the stoichiometric amount of hydrogen sulfide necessary to precipitate sulfides of mercury with further contact with an amine that is an absorption agent for hydrogen sulfide. Hydrogen sulfide precipitates sulfides of mercury from the gas stream while the amine absorbs the excess hydrogen sulfide to produce a gas stream of minimal sulfur content with a reduced mercury content that can be below the range of detection.