ST1-X - Pelleted Impregnated Activated Carbon

H₂S Capacity

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

• Use of a pellet carbon provides a lower pressure drop than granular carbons thereby reducing electrical costs
• Use of a coal-based pellet ensures a high density product with good mechanical properties producing a product that does not breakdown as readily as coconut-based carbons
• STI-X is the most cost-effective caustically impregnated carbon available today

• CCl4 by weight: 60% (min)
• Moisture by weight: 15% (max)
• H2S Capacity: 0.14 g H2S/cc carbon (min)
• Particle Size: 4 mm

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.

• Ash Content by weight: 12%
• Ball Pan Hardness: 95 (min)

Design Considerations
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.