Sealing parts demonstrate outstanding resistance to hot amines amines and strong oxidizers in gas sweetening processes
Oil refineries and gas plants process crude oil and natural (sour) gas containing higher concentrations of hydrogen sulphide (H2S) than ever before, but the hot amine “sweetening” treatments used to remove H2S cause commonly used fluoroelastomer (FKM) and perfluoroelastomer (FFKM) materials used to seal pumps, valves and other vital process equipment to fail more frequently, risking toxic leakage and potentially costly downtime.
Swelling caused by exposure to hot, toxic and aggressive chemicals is the biggest enemy of a sealing material. It can lead to extrusion and rupture of the seal, and eventual leakage of the process stream. The environment found in amine gas sweetening processes has become a particular challenge to sealing material suppliers and to valve, pump and mechanical seal manufacturers.
A major chemical company in France, processing a mix of amines, ethylene oxide and other chemicals at 150°C, reported that conventional FFKM O-rings survived the hazardous and highly aggressive process conditions for only 15 days before requiring replacement.
The chemical company decided to replace the competitive broad resistance FFKM grade O-rings with Kalrez® Spectrum™ 6380 perfluoroelastomer sealing parts, and gained seven times longer seal lifetime as a result. Following the refit, the Kalrez® O-rings survived for 3.5 months in the same process conditions.
According to the company, the benefits of installing Kalrez® Spectrum™ 6380 parts have been seen in increased system efficiency, significantly extended Meantime Between Repairs (MTBR), greater reliability and enhanced safety from reduced risk of potentially dangerous chemical leaks. Ultimately, this has led to valuable annual savings in reduced total system cost.
Kalrez® Spectrum™ 6380 parts offer outstanding resistance to amines and strong oxidizers at high temperatures in gas sweetening processes, and exhibit 10 to 15 times lower swell than FKM, and four times lower swell than general purpose FFKM in such environments.
Kalrez® Spectrum™ 6380 represents a new benchmark in swell-resistant elastomeric sealing materials. By exhibiting as little as 5% swell after long-term exposure to highly toxic hydrogen sulphide and water/amine mixture (see chart), it represents the optimum in FFKM sealing performance.
Kalrez® Spectrum™ 6380 perfluoroelastomer parts have been specifically developed for static and dynamic sealing applications in chemical processes involving hot, aggressive amines and strong oxidizers. The DuPont FFKM has excellent mechanical properties and can operate at a maximum application temperature of 225°C, with short-term excursions to higher temperatures.
The latest Kalrez® 0090 parts represent another option for this application when high pressure resistance is needed. In rigorous third-party laboratory testing for rapid gas decompression (RGD) resistance, Kalrez® AS568-312 O-rings received the best possible rating of 0000 per the NORSOK M-710 Rev 2 standard*
*Test gas: 10% CO2 in methane; Test temperature: 100°C; Test pressure: 150 bar; Decompression rate: 20 bar/minute; Seal size: BS 1806 size 312; Section diameter: 5.33 mm, nominal; Groove fill: 67%, nominal.