Tailor-Made Materials for High Temperature Applications: New Strategies for Radiant Coil Material Development

Schmidt + Clemens and the R&D partner HDZ, a High-Tech R&D Institute for Materials- and Surface Technology, have developed a new and unique bench-scale unit to simulate high temperature corrosion of alloys for petrochemical plants. The unit provides the possibility to examine samples at steam cracking conditions: e.g. high metal temperatures/lower gas temperatures, low residence and a gas mixture which is corresponding to the composition within the outlet tube of a radiant coil. The oxide layers formed during the start-up of a cracking furnace are examined for different holding times, surface conditions etc., also the catalytic coke formation on oxidized surfaces. This provides valuable information on the amount and location of catalytically active sites formed on the oxide layer. In order to evaluate the oxide layer stability of alloys after several runs, samples are exposed to controlled coking and de-coking cycles under various conditions. This test rig provides the possibility to add feed contaminants or reactive elements into the process gas for testing their specific influence on materials deterioration. It is the aim to “tailor- made” tube materials in dependence of the specific coil design and the operating conditions.

Exemplary test results of conventional and experimental alloys will be presented.