Laboratory long-term metal dusting tests and field test was conducted for several Ferrous and Ni alloys to evaluate the metal dusting behavior. The test specimens were reacted with a CO-H2-CO2-H2O gas mixture which simulates synthetic gas produced in reforming plants. The carbon activity of the test was 46.5 which was a very severe environment. Several pits were observed on the specimens of conventional Ni alloys after exceeding 2,000 h when the heating at 575°C for 50h was periodically. The hybrid-suppression technique of new Ni alloy, a new concept for prevention of metal dusting, is based on the formation of protective oxide scales and the reduction of reactivity with CO gas in syngas environments. The new alloy had no pits.

As next step, a field test in a commercial Gas to Liquid (GTL) plant was conducted. The field test duration and temperature was 15,000 h and 520°C, giving a carbon activity of 175.8. Several pits have developed on the specimens of conventional Ni alloys after test and the new alloy had no pits, indicating better metal dusting resistance than the other alloys. The test results have proven that the novel technique holds great promise in the variety of severe carbonaceous environments.

Subject
Pits, New alloys, Materials, Metal surfaces, Nickel based alloys, Commercial alloys, Syngas, Oxide scales, Scale formation, Metal dusting, Carbon, Alloys, Test specimen
Keywords:
metal dusting, carburization, syngas, nickel alloy, oxide, Cu, dissociative adsorption, field test, GTL plant
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2012
Association for Materials Protection and Performance (AMPP)
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