effect of ceramic coating on the thermal performance of an industrial steam methane reformer

Steam methane reformers compose many tubes full of catalysts inside a combustion chamber, producing synthesis gas in tubes. the combustion chamber has burners in order to provide heat of endothermic steam methane reforming reactions in tubes. the dominant heat transfer mode between combustion chamber and tubes is radiation, and a major problem that arises in heat radiation is emissivity factor reduction in surfaces of steam reformer along times. therefore, the portion of radiation heat transfer decreases and then tubes wall temperature reduces, which has a high effect on the reactions in tubes. in this work, an industrial reformer has been investigated for ten years. computational fluid dynamic (cfd) is applied to compare the performance of this reformer at the first and tenth years of operation. results show that the application of ceramic coating with a high emissivity factor has significant effect on thermal performance of old reformers. this change leads to an increase of about 40 k in tubes temperature in the 10th year, which is 3k more than that in the first year