‘O’ RINGS SWEETEN SOUR GAS PROCESSING

The Dupont™ Kalrez® Spectrum™ 6380 is a non-black sealing product, that has been specifically developed for chemical processing applications involving hot and aggressive amines. Amine plants are operated throughout the world, typically in oil refineries and gas plants for the removal of H2S (hydrogen sulphide) from a product stream such as natural gas. New sources of oil and natural gas fields in the Middle East can incorporate up to 30% of H2S which is known as ‘sour gas’. However, the new, stricter environmental standards require ever decreasing contents of H2S, and the process of removing this contaminant from natural gas is commonly referred to as sweetening.

H2S is highly toxic and needs to be handled with care as it can cause embrittlement in metal equipment. Together with the harsh chemical environments and high temperatures that amine processes operate under, destructive swelling can occur with conventional elastomeric sealing components including fluoroelastomers (FKM) and perfluoroelastomers (FFKM). Loss of mechanical properties and extrusion of O-ring seals can result, leading to leakage and increased valve operating torques where seal face deformation has also occurred.

These problems have led to the development of the Kalrez® Spectrum™ 6380 range by Dupont™, designed to provide extended seal performance and operating life for applications in chemical and hydrocarbon processes involving hot, aggressive amines, strong acids and oxidising media. The extension to MTBR (Mean Time Between Repairs) of valves and pump mechanical seals, together with process leakage reduction helps to reduce maintenance costs while also lowering emissions. Typically the tripling of seal service life to one full year of trouble-free operation has been achieved for current users.

Identified by their cream colour, these products are suitable for both static and dynamic sealing, and together with other specialised sealing products in the Kalrez® Spectrum™ range, are all available in the UK from Dichtomatik Ltd, an authorised Dupont™ distributor.

In test results the Kalrez® Spectrum™ 6380 perfluoroelastomer products exhibit outstanding resistance to amines and strong oxidisers, exhibiting 10 – 15 times lower swell compared to FKM and four times lower swell over general purpose FFKM sealing items. The products are also suitable for continuous use at temperatures up to 225°C, with occasional excursions at even higher temperatures for short durations. They can be supplied in standard AS568 and metric sizes, with custom O-ring sizes and other shapes also available.