A power plant with a fossil fuel fired boiler, an air feed system, flue gas system and condensate system. A unitary flue gas heat exchanger spans a bypass line in the flue gas system and the condensate system so as to improve the thermal efficiency of the power plant while minimising complexity.

A method for improving effectiveness of a steam generator system includes providing air to an air preheater in excess of that required for combustion of fuel and providing the air at a mass flow such that the air preheater has a cold end metal temperature that is no less than a water dew point temperature in the air preheater and such that the cold end metal temperature is less than a sulfuric acid dew point temperature. The method includes mitigating SO.sub.3 in the flue gas which is discharged directly from the air preheater to a particulate removal system and then directly into a flue gas desulfurization system. Flue gas reheat air is fed from the air preheater to heat the flue gas prior to entering a discharge stack to raise the temperature of the flue gas to mitigate visible plume exiting and to mitigate corrosion in the discharge stack.

A coal fired oxy boiler power plant is disclosed in which a steam coil oxygen preheater located on an oxygen line Air Separation Unit is thermally integrated with the condensate system. Thermal energy for the steam coil oxygen preheater is provided via an extraction line connected to a steam extraction port of an intermediate pressure steam turbine. A drain line of the steam coil oxygen preheater fluidly connects the steam coil oxygen preheater to a point of the Rankine steam cycle fluidly within the condensate system.

A coal fired oxy boiler power plant is disclosed in which a steam coil oxygen preheater located on an oxygen line Air Separation Unit is thermally integrated with the condensate system. Thermal energy for the steam coil oxygen preheater is provided via an extraction line connected to a steam extraction port of an intermediate pressure steam turbine. A drain line of the steam coil oxygen preheater fluidly connects the steam coil oxygen preheater to a point of the Rankine steam cycle fluidly within the condensate system.

An apparatus for using a water coil air heater with a single bank economizer. A boiler economizer arrangement includes an economizer bank which has separate hot pass bank and cold pass bank economizer portions in a parallel arrangement, each facing the same flow of hot flue gas. Feedwater enters the cold pass bank economizer where it is heated by the hot flue gas, and then flows to a water coil air heater away from the hot flue gas. The feedwater dissipates heat energy in the water coil air heater which may be used to heat air bound for combustion. The feedwater continues into the hot pass bank economizer portion of the economizer arrangement where it absorbs additional heat from the flue gas. The heated feedwater flows out of the economizer arrangement and may be subject to additional heating by a boiler or other heat exchanger.

An apparatus for using a water coil air heater with a single bank economizer. A boiler economizer arrangement includes an economizer bank which has separate hot pass bank and cold pass bank economizer portions in a parallel arrangement, each facing the same flow of hot flue gas. Feedwater enters the cold pass bank economizer where it is heated by the hot flue gas, and then flows to a water coil air heater away from the hot flue gas. The feedwater dissipates heat energy in the water coil air heater which may be used to heat air bound for combustion. The feedwater continues into the hot pass bank economizer portion of the economizer arrangement where it absorbs additional heat from the flue gas. The heated feedwater flows out of the economizer arrangement and may be subject to additional heating by a boiler or other heat exchanger.

A method for improving effectiveness of a steam generator system includes providing a steam generator system including a steam generator vessel, an air supply system and an air preheater. The air supply system is in communication with the steam generator vessel through the air preheater and the steam generator vessel is in communication with the air preheater. The air supply system provides a first amount of air to the air preheater. At least a portion of the first amount of air is provided to the steam generator vessel. A flue gas mixture is discharged from the steam generator vessel. At least a portion of the flue gas mixture flows into the air preheater. SO.sub.3 in the flue gas mixture is mitigated before the flue gas mixture enters the air preheater.

A fire tube boiler system including a plurality of oxygen transport reactors that heats a working fluid. Each oxygen transport reactor has a first inner tube with an ion transport membrane that receives air from a first supply line, extracts oxygen from the air, and evacuate oxygen depleted air through a first exhaust line, a second inner tube that surrounds the first inner tube that receives the oxygen from the ion transport membrane and a mixture of fuel and carbon dioxide from a second supply line and produces a oxy-combustion, and an peripheral tube that surrounds the second inner tube and evacuates the exhaust gases produced by the oxy-combustion and transfer heat from exhaust gases to the working fluid and the ion transport membrane.

A fire tube boiler system including a plurality of oxygen transport reactors that heats a working fluid. Each oxygen transport reactor has a first inner tube with an ion transport membrane that receives air from a first supply line, extracts oxygen from the air, and evacuate oxygen depleted air through a first exhaust line, a second inner tube that surrounds the first inner tube that receives the oxygen from the ion transport membrane and a mixture of fuel and carbon dioxide from a second supply line and produces a oxy-combustion, and an peripheral tube that surrounds the second inner tube and evacuates the exhaust gases produced by the oxy-combustion and transfer heat from exhaust gases to the working fluid and the ion transport membrane.

A fire tube boiler system including a plurality of oxygen transport reactors that heats a working fluid. Each oxygen transport reactor has a first inner tube with an ion transport membrane that receives air from a first supply line, extracts oxygen from the air, and evacuate oxygen depleted air through a first exhaust line, a second inner tube that surrounds the first inner tube that receives the oxygen from the ion transport membrane and a mixture of fuel and carbon dioxide from a second supply line and produces a oxy-combustion, and an peripheral tube that surrounds the second inner tube and evacuates the exhaust gases produced by the oxy-combustion and transfer heat from exhaust gases to the working fluid and the ion transport membrane.