FUEL 249 |
| Steam methane reformer (SMR) components are subject to coking and corrosion by metal dusting. Costly alloys have been developed to minimize the problem but all have limited resistance to metal dusting in the highly carburizing environment. Several materials, such as alumina, are well known to inhibit carburization and metal dusting (Grabke et al. 1998) but uniform application is a challenge, particularly in the narrow channels of a microchannel SMR device, such as that under development at Velocys. Velocys and its manufacturing partner have developed a proprietary process that produces a dense ceramic coating that resists coking and metal dusting. Results from recent tests conducted with assistance of a State of Ohio Third Frontier Grant show that the coating inhibits metal dusting and offers substantially better protection against metal dusting and coke formation than heat treated nickel alloy. While pitting as resulted from metal dusting is clearly visible to naked eyes after only ~100 hr on-stream with the conventional thermally grown chromia scale at the surface, no pitting is seen under an optical microscope with the protective coating after ~600 hr on stream under the same testing conditions of steam-to-carbon ratio 1.25 at 25 atm, covering a temperature range of ~350 to 850 C. Moreover, this coating can be applied uniformly to a microchannel reformer and microchannel recuperators. In addition to a discussion of the surface protection coating, other work covered by the State of Ohio grant will be shared, including the operation of the latest generation of microchannel SMR reactor and plans to migrate Velocys' commodity hydrogen product to fuel cell applications. REFERENCE Grabke, H.J., E.M. Muller-Lorenz, J. Klower, D.C. Agarwal. July 1998. “Metal Dusting of Nickel-Based Alloys.” in Materials Performance. NACE International, Houston, TX.
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Fuel Processing for Hydrogen Production: Small-Scale Hydrogen Generation Status and Future Challenges
8:25 AM-12:10 PM, Thursday, August 23, 2007 Boston Park Plaza -- Berkeley Rm, Oral
Division of Fuel Chemistry |