Comparing Method Analysis for Lower Steam Temperature of 660MW Supercritical Lignitic Boiler

The problem of lower main steam temperature(MST) of a supercritical boiler designed for burning high moisture lignite is analyzed. By comparing to another structure-similar subcritical boiler, the effects of coal, furnace size, combustion mode and heating surface distribution are studied. The results show that the major cause of this lower MST problem is unduly decline of high temperature heating area due to over-estimating the heat transfer capability of the upper furnace water wall of the supercritical boiler. At last, this document suggests to the increase the size of rear part of partition platen superheater(SH) to solve the problem and has a certain actual guiding reference.