DEVICE FOR CONTROLLING AMOUNT OF NITROGEN OXIDE IN WASTE GAS OF COMBUSTION TYPE MELTING FURNACE

摘要

PURPOSE:To make it possible to control the amount of nitrogen oxide to a value less than a set value in a state where unburnt matters within an exhaust gas are reduced by measuring the amount of nixtrogen oxide by a gas analyzer and comparing the measured value with the set value. CONSTITUTION:An air inlet pipe 14 with an opening and closing value 13a which introduces blown back air of a filter at every predetermined time and an opening and closing valve switch 13b which closes a gas inlet pipe 12 when introducing air, the provided in the inlet pipe 12 for the gas from a gas filter-collector 10 provided in an exhaust gas passage of a secondary combustion furnace, and the extracted gas is sent to a gas analyzer 11 thereby to continuously meaure the amount of nitrogen oxide. The measuring signal is transmitted to a controller 19 so as to compared the measured value with a set value of the amount of nitrogen oxide, that is, a specific value of 800ppm or less, for example. On the other hand, a fuel flow amount signal of a secondary combustion furnace is transmitted to the controller 19, and the amount of air in accordance with the fuel flow amount is calculated by the controller 19. To the calculated amount of air is added a value with a value deviated from the set value of the amount of nitrogen oxide to adjust the amount of air to be introduced into the secondary combustion furnace and to control the amount of nitrogen oxide within the exhaust gas to less than the set value.