A critical review is made of the experience on DEA and MDEA amine units covering 4decades and more than 100 amine units, with 90% working in sour conditions, i.e. with H2S.For sour amine units, the three key corrosion mitigating issues are to avoid too high flowvelocities, air entries leading to corrosive degradation products and a too high reboiler temperature.All these issues are easily resolved with the design and operating practices detailed in this article.They result from a long term field proven performance of sour DEA and MDEA units working withamine concentrations up to 40% weight.Concerning sweet gases (i.e. with CO2 only) a few DEA units have been subjected tounprecedented corrosion damages mainly occurring on AISI 410 and 304L stainless steels, despiteapparently mild corrosive conditions. This corrosion is shown to be due to a complex and specificinteraction between the metal, the corrosion products and the complexing amine degradationproducts. Field experience also shows the satisfactory resistance of AISI 316L material.This experience is now incorporated in the new design bases of sweet amine units. The useof AISI 316L is extended to all areas potentially prone to corrosion. This solution increasesCAPEX by only 2.0%, including the cost of the initial amine load. It also remains particularlyeconomical with respect to OPEX and fully flexible to the future because not requiring speciallyformulated products. Keeping the versatility and flexibility of amine units to encompass the widestrange of amines, including some in development, is thought to be of particular benefit since theyare always built for long service years.The design bases of these sweet and sour DEA and MDEA processes are the result of acontinuing effort made to the collection and feed-back of experience from existing units, in order toapply the know-how to new ones. These processes from Total are now licensed by Prosernat, anIFP subsidiary.
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