The invention provides an ignition method and device through a high-temperature
high oxygen torch generated by
coal powder or crushed
coal combustion and belongs to ignition method and devices of
coal-burned boilers. The method includes the steps that coal
powder or crushed coal is added to a vertical
fluidized bed precombustion chamber, when the equivalent excessive air coefficient alpha' is larger than 1.3 and smaller than 2.6, the small amount of generated high-temperature high-
oxygen torch which is burnt strongly is sent to a
combustor, and the main fuel is ignited through a
flame step-by-step amplification principle. The device comprises a
plasma generator I, a precombustion chamber I, a main
combustor, a
torch outlet I, a first-level
barrel, a second-level
barrel, a third-level
barrel, a primary air
flue of a precombustor and a secondary air
flue of a precombustor. By means of the ignition method and device, coal
powder boiler oil-free ignition, circulating
fluidized bed oil-free ignition, low-load stable
combustion and low-
nitrogen combustion can be achieved. The ignition method and device have the advantages that the precombustor is simple, reliable and free of coking after being operated for a long time; an external heat source, such as a
plasma or oil gun can stop working after ignition is stable, and the precombustor is relied on for achieving stable combustion.