Water from Air Scrubbers
For some small medical waste incinerators, the exhaust gas is passed through a water scrubber to remove particulates and water-soluble compounds. If mercury (Hg) is present in the exhaust, it will be contained in the scrubber water. This scrubber water, containing 0.3 ppmw mercury is passed through a column of MERSORB® LW to remove the mercury. Effluent levels of less than 0.2 ppbw Hg are being obtained.
Mercury Cell Hydrogen
High purity hydrogen chloride (HCl) is manufactured by reacting hydrogen and chlorine. One location uses hydrogen from mercury cells and the mercury must be removed to meet the specifications for the HCl. Mercury concentrations up to 300 ppb were reduced to less than 0.01 ppb in a single column of MERSORB® 3 mm diameter pellets. This system has been in operation for over eight years with 100% mercury removal.
Natural Gas Processing
A large liquefied natural gas (LNG) plant in Northern Algeria was processing natural gas with high mercury content in aluminum heat exchangers. In order to protect the equipment from corrosion, large beds of MERSORB® 4 mm pellets were installed. There are also several installations of MERSORB® adsorbent in U.S. LNG plants.
A gold mining plant in Nevada encountered concentrations well above the TLV in the enclosed processing area. An air purification system containing MERSORB® 3 mm pellets was installed. The mercury level has been reduced to below the TLV.
Mercury Waste Remediation
Waste materials containing mercury are retorted to make them non-hazardous. The effluent gas is cooled to recover liquid mercury but the temperature must remain above the water boiling point to prevent large quantities of condensate. The high temperature capability of the MERSORB® adsorbent provides good efficiency at temperatures of 250°F. The pelleted adsorbent provides good flow distribution.
Mercury Removal from Waste Water
Water containing up to 100 ppmw mercury is processed in a system which includes pretreatment to reduce the mercury levels to around 1 ppmw. Three vessels in series, containing MERSORB®LW mercury adsorbent, reduce the concentration to <20 ppbw The water can then be disposed of as non-hazardous waste. Empty bed contact times (EBCT) range from 20-30 minutes at a feed water pH of 7.0.
Fluorescent Lamp Recycling
A major manufacturer of fluorescent lamp recycling machines uses MERSORB® Hg adsorbents in both its original and new model machines. The treated air is within regulatory emission control limits.