Abstract: A combustion apparatus including a mixture feeding pipe for injecting a mixture of pulverized coal for combustion air into a furnace, with the mixture being then ignited. A first gas feeding passage is disposed outwardly of the mixture feeding pipe for feeding oxygen-containing gas into the furnace, with a second gas feeding passage being disposed between the gas feeding passage and the mixture feeding pipe, in a radial direction, for feeding the oxygen-containing gas into the furnace. A projection is disposed between the gas feeding passage and the mixture feeding pipe and extends at an exposed end surface thereof into the furnace beyond an exposed end of the mixture feeding pipe, with the projection being hollow for allowing the oxygen-containing gas to flow within the projection.

Abstract: A combustion apparatus including a mixture feeding pipe for injecting a mixture of pulverized coal and combustion air into a furnace, with the mixture then being ignited. A radially outwardly flared flame maintaining ring is provided at a tip end of the mixture feeding pipe, with the maintaining ring being exposed to a reduced atmosphere and to high temperatures due to radiant heat from the furnace. A projection extends into the furnace beyond the flame maintaining ring so as to protect the flame maintaining ring from radiation from inside the furnace thereby suppressing an excessive increase in temperature. Combustion air flows along a surface of the projection so as to provide at oxidized atmosphere.

Abstract: A pulverized coal combustion apparatus comprises a burner through which pulverized coal and carrier air are passed to be burnt in a combustion chamber, and a flame retainer disposed at an end of the burner. The flame retainer includes a flared tube and an annular plate, which plate has a plurality of radially inwardly projecting parts equiangularly spaced from each other. The annular plate comprises a plurality of ceramic pieces and a plurality of fastener elements, both of which are arranged and assembled alternately to form the annular plate. Each ceramic piece is so shaped that it projects radially inwardly to serve as the projecting part when assembled. The ceramic piece has at opposite sides thereof smoothly curved edge surfaces, and the fastener element has at opposite sides thereof smoothly curved edge surfaces which are engaged with the curved edge surfaces of neighboring two ceramic pieces.

Abstract: A combustion apparatus for low concentration NOx for burning gas, oil and coal along the same axis, having overcome the drawbacks of the prior art, without hindering the whirling of the air and also having prevented clogging of the nozzle and combustion vibration is provided, which apparatus is provided with a means for carrying pulverized coal by a primary air, a means for feeding a gas fuel through a gas nozzle, a means for separating combustion air into a secondary air and a tertiary air and feeding these airs, and a means for feeding and spraying an oil, and which apparatus is characterized by providing an annular space part between the flow paths of the secondary air and the tertiary air; and also arranging the gas nozzle penetrating through the annular space part in a movable manner in the axial direction.

Abstract: A coal combustion apparatus capable of improving NO.sub.x reduction to a large extent is provided, which apparatus comprises a pulverized coal-feeding pipe (abbreviated to coal pipe) inserted into a burner throat on the lateral wall of a combustion furnace and for feeding the coal and air into the furnace; a means for feeding the coal and air into the coal pipe; a secondary air passageway formed between the coal pipe and a secondary air-feeding pipe provided on the outer peripheral side of the coal pipe; a ternary air passageway formed on the outer peripheral side of the secondary air-feeding pipe; a means for feeding air or an oxygen-containing gas into the secondary air passageway and that into the ternary air passageway; and a bluff body having a cross-section of a L-letter form provided at the tip end of the coal pipe.