Abstract: A pressurized internal circulating fluidized-bed boiler is incorporated in a combined-cycle electric generating system in which a fuel such as coal, petro coke or the like is combusted in a pressurized fluidized bed and an exhaust gas produced by the combusted fuel is introduced into a gas turbine. The pressurized internal circulating fluidized-bed boiler includes a pressure vessel, a combustor disposed in the pressure vessel and a main fluidized bed combustion chamber provided with an air diffusion device. A thermal energy recovery chamber is partitioned from the main combustion chamber by an inclined partition wall. A fluidized medium flows into and out of the main combustion chamber and the thermal energy recovery chamber. A free board is provided integrally above the main combustion chamber and the thermal energy recovery chamber so that combustion gas from the main combustion chamber and the thermal energy recovery chamber is mixed in the free board.

Abstract: A method of combustion of pulverized coal in two stages of combustion to reduce the amount of NOx produced by combustion. In a first stage, exhaust gas is added to air for combustion in a proportion of 35-60% of the air necessary for carrying out combustion. In a second stage, air for combustion is supplied in a proportion of 25-35% of the air necessary for carrying out combustion. In this method of combustion, the pulverized coal is combusted slowly at low temperature with the formation of a flame of low brightness to produce in large amounts activated intermediate components responsible for denitration reaction to promote reduction of produced NOx, and the concentration of CO produced can be reduced by abstaining from using the minimum air necessary for combustion.

Abstract: A pulverized coal burner including a primary throat having at its forward end a swirler for feeding pulverized coal and primary air in vortical flow, a secondary throat located outside the primary throat for supplying secondary air and a burner throat located outside the secondary throat for supplying tertiary air, the secondary and burner throats being located concentrically with the primary throat having at its forward end a flame sustaining plate diverging outwardly to cause the secondary and tertiary air to flow away from the primary throat along the inner surface of the outwardly diverging forward end portion of the burner throat, to thereby avoid mixing of the secondary and tertiary air with the pulverized coal air in a primary flame region in which the pulverized coal burns slowly and produces NOx in reduced amount.

Abstract: A pressurized internal circulating fluidized-bed boiler is incorporated in a combined-cycle electric generating system in which a fuel such as coal, petro coke or the like is combusted in a pressurized fluidized bed and an exhaust gas produced by the combusted fuel is introduced into a gas turbine. The pressurized internal circulating fluidized-bed boiler includes a pressure vessel, a combustor disposed in the pressure vessel and a main fluidized bed combustion chamber provided with an air diffusion device. A thermal energy recovery chamber is partitioned from the main combustion chamber by an inclined partition wall. A fluidized medium flows into and out of the main combustion chamber and the thermal energy recovery chamber. A free board is provided integrally above the main combustion chamber and the thermal energy recovery chamber so that combustion gas from the main combustion chamber and the thermal energy recovery chamber is mixed in the free board.