Simulated fireside corrosion of T91 in oxy-combustion systems with an emphasis on coal/biomass environments |
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| Authors: | Gordon R Holcomb Casey S Carney Joseph Tylczak Tomasz P Dudziak Nigel J Simms |
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| Affiliation: | 1. Structural Materials Team, Materials Engineering &2. Manufacturing Directorate, Research &3. Innovation Center, National Energy Technology Laboratory, Albany, OR, USA;4. Leidos Research Support Team, Pittsburgh, PA, USA;5. Centre for Thermal Energy Systems and Materials, Cranfield University, Cranfield, Bedfordshire, UK |
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| Abstract: | Oxy-combustion is the burning of a fuel in oxygen rather than air for the ease of capture of CO2 for reuse or sequestration. Corrosion issues associated with the change in heat exchanger tube operating environment (replacement of most of the N2 with CO2 and potentially higher SOx levels) from air- to oxy-combustion were examined. The ferritic-martensitic alloy T91 was used in accelerated fireside corrosion tests using several different gas compositions and ash deposit overcoats to simulate air-fired, oxy-fired coal, and oxy-fired co-fired coal/biomass conditions. Initial corrosion was observed after 240 h of exposure by examining cross-sections with retained ash. Metal section losses were determined after exposures of up to 1440 h at 600–700°C. Severe corrosion was observed, and a corrosion response with respect to ash deposit chemistry was observed. Corrosion response differences with respect to gas phase chemistry were minimal. Alloy-oxide scale-ash morphologies were consistent with oxide fluxing mechanisms. |
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| Keywords: | Fireside corrosion oxidation oxy-combustion co-firing boilers fluxing T91 |
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