Correction and Its Application for Flue Gas Measured Temperature of Boiler

The thermocouples of K type with one layer casing for reducing heat transfer by radiation was used to measure the flue gas temperature of two boilers with 670t/h evaporation. In order to diminish the measurement error, this paper offers a theoretical calculation method to correct the measured temperature basing on the heat transfer theory, the extraction thermocouple with three layers ceramic casing was used to check the reliability of corrected temperature. The measured temperature by extraction thermocouple is access to the corrected temperature, which means that the correction method in this paper has feasibility. This paper obtained the flue gas temperature and its distribution of two boilers with 670t/h evaporation applying such correction method, and analyzed the reasons why the reheat steam temperature is lower than design temperature for one of boilers. Although the flue gas temperature correction method in this paper isn’t perfect, it is benefit for improving the accuracy of measured temperature, reducing the temperature errors, and it has directive and reference functions for test or research engineers.