4mm pelletized coal base virgin activated carbon with impregnant used for hydrogen sulfide removal from air streams. STI-X is a coal-based pellet carbon designed for the removal of acid gases and odor compounds from air. It is manufactured by high-temperature steam activation followed by chemical impregnation. This carbon is a proven product for many odor control applications, including industrial processes, municipal treatment plants, paper plants, and indoor air filtration. It provides very high capacity for compounds that are not strongly adsorbed by standard carbon, including hydrogen sulfide (H2S), mercaptans, sulfur dioxide, chlorine, and hydrogen chloride.
Based on testing per ASTM D-6646, the H2S capacity specification for STI-X is 0.14 g/cc, or about 25% by weight The following plot can be used to estimate the rate of use of STI-X carbon as a function of air flow and H2S concentration. For intermediate flow rates the usage can be estimated.
Compared to other caustically impregnated carbons, STI-X has several advantages
The impregnants on this carbon have been shown to decrease the ignition temperature of the carbon. This product passes the United Nations Self-heating Test and is therefore deemed suitable for shipment without concern over it self-heating. However, in some circumstances when the carbon is left open to air and low convective flow of air passes through it, the carbon can self-heat and ignite. Therefore, when a vessel containing carbon is out of service or in storage, care should be taken to prevent convective airflow which can be prevented with the installation of blind flanges on inlet and outlet connections.
STI-X is applied in fixed-bed adsorbers operated in an upflow, downflow, and cross-flow mode. Bed depths typically range from 18 inches (46 cm) to 36 inches (92 cm) at superficial velocities between 50 to 90 feet per minute (0.25 m/s to 0.46 m/s). For effective H2S control, the gas stream must contain free oxygen and the stream humidity must be in excess of 10%. For applications where organic compounds (VOC's) must be removed in addition to H2S, or where especially long carbon life is desired and potable water is available, Calgon Carbon Corporation recommends the use of its CENTAUR catalytic activated carbon in lieu of STI-X. CENTAUR can be regenerated in place for continued H2S removal simply by washing the carbon with water. Ask your Calgon Carbon Corporation Technical Sales Representative for more information on this product.