LOW NOX BURNER FOR BOILER, LOW NOX BOILER AND THEIR OPERATION

摘要

PURPOSE:To miniaturize the size and reduce NOX by providing a burner for premixture gas flame round a burner for the expanded flame and a flame holding device with which the jet gas collides to form a circulating flow at a position downstream of the jet opening of the burner for the premixture gas flame. CONSTITUTION:A burner is constituted of a cylindrical burner 1 for expanded premixture gas flame that is installed at the center and an annular gas flame burner for premixture gas flame that is installed on the outer circumference of the burner 1. The burner 1 for the expanded flame has a fuel nozzle 3 in the center and air nozzles 4 are installed on its circumference. The burner 2 for premixture gas flame is constituted of nozzles 7A, 7B, 7C and 7D which are the divisions of an annular channel into four parts, fuel and air mixing means 8 and a flow straightening means 9 for the mixkture gas. Each opening of the nozzles 7A - 7D is provided with a plate-shaped flame holder 12 at right angle to the direction of the main flow in the jet stream of the mixture gas. With this constitution the combustion of the premixture gas is easy to advance from the center of the jet stream so that the stability of the premixture gas flame is raised and also it is possible to reduce NOx a great deal.