The present invention relates to a pulverized coal fired boiler with wall-attachment secondary air and grid overfire air. Primary burners including primary air spouts, secondary air spouts and close coupled overfire air spouts arranged at intervals along the height direction of a hearth are arranged on four corners of the hearth. Two-way wall-attachment secondary air spouts and one-way wall-attachment secondary air spouts are arranged from bottom to top in a primary combustion zone where the primary burners are located. One-way wall-attachment secondary air spouts are arranged in a reduction zone between the primary burners and the top overfire air spouts, and grid overfire air spouts are arranged in a burnout zone where the overfire air is supplied. By adopting the pulverized coal fired boiler with wall-attachment secondary air and grid overfire air according to the present invention, the NO amount generated in the hearth is reduced, the NO reduction rate along a flame is improved, the coke burnout rate is improved, less coke which is not burnt out enters into the burnout zone, slagging on the water-cooled wall is reduced, and ultralow emission of NOx may be realized on the premise that the combustion efficiency is not reduced, slag is not agglomerated in the hearth and the flue gas temperature deviation is small.

A steam generating system includes a furnace, a nozzle tip assembly for pulverized coal and primary air as well as means for conveying secondary air in the furnace. The nozzle according to the invention comprises a nozzle body (3) and several channels (5) being connected with the nozzle body, the channels are diverging from each other. At the exit faces (17) of the channels obstructions (13) are disposed to induce huge turbulences of the primary air when entering the furnace. Due to these turbulences the primary air and the entrained coal are mixed very well before being combusted in the furnace. This results in a better more effective combustion with reduced NOx-emissions.

A steam generating system includes a furnace, a nozzle tip assembly for pulverized coal and primary air as well as means for conveying secondary air in the furnace. The nozzle according to the invention comprises a nozzle body (3) and several channels (5) being connected with the nozzle body, the channels are diverging from each other. At the exit faces (17) of the channels obstructions (13) are disposed to induce huge turbulences of the primary air when entering the furnace. Due to these turbulences the primary air and the entrained coal are mixed very well before being combusted in the furnace. This results in a better more effective combustion with reduced NOx-emissions.

A pulverized coal burner for an oxyfuel combustion boiler which attains uniform combustion from a pulverized coal burner and which constrains a temperature rise of an oxygen injection nozzle is provided. The burner includes burner inner and outer cylinders arranged to penetrate a wind box and come close to a throat portion. A pulverized coal feed passage is provided between the burner inner and outer cylinders. A plurality of oxygen injection devices are arranged outwardly of the burner outer cylinder so as to directly feed oxygen ahead of the burner outer cylinder.

A pulverized coal burner for an oxyfuel combustion boiler which attains uniform combustion from a pulverized coal burner and which constrains a temperature rise of an oxygen injection nozzle is provided. The burner includes burner inner and outer cylinders arranged to penetrate a wind box and come close to a throat portion. A pulverized coal feed passage is provided between the burner inner and outer cylinders. A plurality of oxygen injection devices are arranged outwardly of the burner outer cylinder so as to directly feed oxygen ahead of the burner outer cylinder.

A system and method of igniting a coal air-fuel mixture, including a burner having a burner tube operable to carry a flowing mixture of fuel and air to a furnace for combustion therein and a first flow directing device disposed within the tube, operable to direct a first portion of the flowing fuel and air mixture to a location in the burner tube. The system also includes a laser igniter within the burner tube, the laser igniter including a laser tube having a first end with a laser light input and a second end with a light output, and a laser light source operably coupled to the laser light input. The laser light source, including a laser. The laser ignitor directing photons from the light output at the location in the burner tube to ignite at least a part of the first portion of the fuel.

This solid fuel burner is provided with: a venturi tube in which a channel for mixed fluid in a fuel nozzle narrows toward the center in the channel cross section; a fuel concentrator that imparts, to the mixed fluid, a velocity component away from the center of the fuel nozzle; and a channel separation member that separates the channel of the fuel nozzle into an internal side and an external side; wherein the channel separation member is shaped in such a way that the cross sectional area of an external channel is larger at the downstream end than at the upstream end, and the upstream end of the fuel concentrator is located between the upstream end and the downstream end of an expanded portion of the venturi tube. This solid fuel burner prevents solid fuel particles, which is ground biomass fuel, from adhering and depositing inside the nozzle.

This solid fuel burner is provided with: a venturi tube in which a channel for mixed fluid in a fuel nozzle narrows toward the center in the channel cross section; a fuel concentrator that imparts, to the mixed fluid, a velocity component away from the center of the fuel nozzle; and a channel separation member that separates the channel of the fuel nozzle into an internal side and an external side; wherein the channel separation member is shaped in such a way that the cross sectional area of an external channel is larger at the downstream end than at the upstream end, and the upstream end of the fuel concentrator is located between the upstream end and the downstream end of an expanded portion of the venturi tube. This solid fuel burner prevents solid fuel particles, which is ground biomass fuel, from adhering and depositing inside the nozzle.

A two-channel burner includes a pulverized coal supply mechanism, a transition channel, an inner secondary air guide tube, an outer secondary air guide tube, a combustion stabilizing chamber, and a flow smoothing chamber. The outer secondary air guide tube, the combustion stabilizing chamber, and the flow smoothing chamber are sequentially connected to form a burner body. The pulverized coal supply mechanism passes through an interior of the burner body. The transition channel is fitted over the pulverized coal supply mechanism. The inner secondary air guide tube is disposed between the transition channel and the outer secondary air guide tube and forms an inner secondary air passage together with the transition channel, and forms an outer secondary air passage together with the outer secondary air guide tube. An outlet end of the inner secondary air guide tube is formed to have a flared opening.

The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO.sub.2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO.sub.2 circulating fluid. Fuel derived CO.sub.2 can be captured and delivered at pipeline pressure. Other impurities can be captured.