A low-load stable-
combustion direct-current
combustor comprises a
natural gas pipeline. The
natural gas pipeline extends to a central air duct to supply
natural gas, a
cyclone arranged at the outlet of the central air duct conveys
mixed gas to a precombustion chamber for
combustion, a primary air
pipe providing primary pulverized
coal to the precombustion chamber is arranged outside the central air duct, an internal secondary blowdryer providing internal secondary air to the precombustion chamber is arranged outside the primary air
pipe, an external secondary blowdryer providing external secondary air to the precombustion chamber is arranged outside the internal secondary blowdryer, the precombustion chamber is divided into an expansion section and a horizontal section along the inlet direction of the
mixed gas, an internal-secondary-air annular
nozzle is arranged in the intersection of the expansion section and the horizontal section, the internal secondary air is in annular direct-current incidence from the internal-secondary-air annular
nozzle,
combustion supporting function is achieved,
slag build-up and pulverized-
coal accumulation can be avoided; the external secondary air is injected in a direct-current oblique manner to supplement air needed for subsequent combustion of pulverized
coal flow, and meanwhile, formation of
NOx is reduced. By the arrangement, low-load stable combustion of a pulverized-coal
combustor can be realized, and deep participation in peak regulating of a coal-fired power
plant is favorably improved.