ABNORMAL TEMPERATURE RISE PREVENTION METHOD OF DENITRATION DEVICE OR AIR PREHEATER

摘要

PURPOSE:To prevent the generation of abnormal heat by judging the generation degree of abnormal heat from signals transmitted from a gas detector which is installed in the downstream side of the air preheater to detect the density of hydrocarbon, CO, NOx, and SOx, and a temperature detector which detects the temperature of waste gas and operating a disaster prevention means based on their detection results. CONSTITUTION:For example, when a CO gas detector detects CO gas, it is considered that the CO gas is generated in a state where unburnt carbon contained in dust adhered or collected on a heat exchanger element of an air preheater is subjected to low temperature oxidation. Therefore, if the detected value reaches an abnormal level, a failure judgment device 20 transmits a signal based on the relation between the density of the detected CO gas and gas generation time so that a disaster alarming and processing device 21 may instruct air purge for example. Then the instructed air purge is executed. Since NOx gas is generated at a temperature of 400 and over while SOx gas is generated at a temperature of 250 deg.C and over, similarly to the detection by a thermometer, the generation phenomena of denitration catalyst or AH heat exchanger element is detected so that the detection status is displayed on the CRT of the failure judgment device 20, and output to the disaster alarming and processing device 21, thereby enabling an operator to take proper measures.