Technical and Economic Analysis on Bimetallic Clad Pipes for Sour Service

Abstract

With the development of sour gas fields in China, the problem of corrosion protection about gathering and transporting pipes used in CO2/H2S-containing condition gradually appeared, and the demand for economic and technical anticorrosion measures became more and more urgent. As we known, non-metallic material could not give consideration to performance and price, carbon steel with corrosion inhibitor was sometimes still seriously corroded and corrosion resistant alloy pipes was too expensive to use independently. Moreover, for bimetallic lined pipes it had hard to get rid of some inherent safety risks. Therefore, bimetallic clad pipes might be the best options for sour service. In order to provide theoretical basis and technical support for engineering application, taking typical sour environment as an example, fit for purpose of materials, processes and cost about bimetallic clad pipes were conducted in this paper. By analyzing materials applicable range, comparing processes reliability and sorting out anticorrosion cost, the superiority about bimetallic clad pipes would be fully demonstrated from the perspective of technology and economy. The results showed that UNS N08825 rather than non-metallic pipe, carbon steel and low alloy steel, UNS S31603 and UNS S31803 could withstand corrosion in sour environments. Additionally UNS N08825 bimetallic clad pipes are more cheaper than UNS N08825, and more reliable than bimetallic lined pipes. Meanwhile UNS N08825 bimetallic clad pipes more economic than carbon steel with corrosion inhibitor in the whole life cycle. In summary, UNS N08825 bimetallic clad pipes, which has the greatest economic and technical superiority in the whole life cycle, might be suitable for sour service.