Investigation of gas turbine material performance in high CO₂ and steam atmospheres

Abstract

Purpose

The use of CO₂ as a replacement for conventional air in combustion gas streams of gas turbine power‐generation equipment is a novel idea and a potential method of providing an almost pure CO₂ stream for subsequent disposal/sequestration. The purpose of this paper is to investigate the effects of this novel gas environment on conventional gas turbine component part materials over the same range of temperatures found in service.

Design/methodology/approach

Test samples of candidate materials were tested in simulated environments using controlled gas and steam supplies to sealed horizontal laboratory furnaces. Conventional weight change tests, metal loss tests and electron microscope examination were used to assess the performance of the materials and compare the oxidation morphology. Spectra of the oxidation products were also used to determine the nature of the oxides formed on selected materials.

Findings

It is found that changes in the percentage of steam in the novel gas environment made little difference to the performance of the selected alloys. However, when the results of the program are compared with typical data from previous works, where the same alloys are exposed in air, there is a distinct trend. Comparison between the data from air exposed samples and data from those in this paper show the high CO₂ environment, envisaged for the GAS‐ZEP concept, to be more aggressive to all of the alloys tested.

Originality/value

This paper describes the first investigation into the performance of candidate materials for the various components around a GAS‐ZEP system in the novel operating environments anticipated. The work has shown that current power plant materials can be considered for use in first generation GAS‐ZEP systems, but that care is required in their selection at the higher operating temperatures.

Citation

Mabbutt, S.J. and Simms, N.J. (2010), "Investigation of gas turbine material performance in high CO₂ and steam atmospheres", Anti-Corrosion Methods and Materials, Vol. 57 No. 4, pp. 192-203. https://doi.org/10.1108/00035591011058200