A method of operating and an arrangement for a steam boiler system including a furnace and along a following flue gas channel a number of superheaters, a number of economizers, and at least one air preheater located in the flue gas channel downstream of the economizers, a fabric filter baghouse located in the flue gas channel downstream of the air preheater, and downstream of the fabric filter baghouse is located a selective catalytic reduction (SCR) system including an SCR reactor, a high pressure steam coil heater upstream of the SCR reactor and a gas-gas heat exchanger connected upstream and downstream of the SCR reactor to transfer heat from flue gas after the SCR reactor to the flue gas upstream of the high pressure steam coil heater.

A method of operating and an arrangement for a steam boiler system including a furnace and along a following flue gas channel a number of superheaters, a number of economizers, and at least one air preheater located in the flue gas channel downstream of the economizers, a fabric filter baghouse located in the flue gas channel downstream of the air preheater, and downstream of the fabric filter baghouse is located a selective catalytic reduction (SCR) system including an SCR reactor, a high pressure steam coil heater upstream of the SCR reactor and a gas-gas heat exchanger connected upstream and downstream of the SCR reactor to transfer heat from flue gas after the SCR reactor to the flue gas upstream of the high pressure steam coil heater.

An energy-saving gas supply boiler system, comprising: a steam boiler, a flue gas pipeline, a heat exchanger, a steam generator and an ejector. The steam boiler comprises a body, a combusting apparatus, a flue gas outlet, a water outlet and a high pressure steam outlet. The heat exchanger comprises a high temperature flue gas inlet, a medium temperature flue gas outlet, a cooling water inlet and a hot water outlet. Cooling water undergoes heat exchange with flue gas and flows out from the hot water outlet. The steam generator comprises a generator body, a hot water inlet and a low pressure steam outlet. The ejector comprises a high pressure steam inlet, a mixing steam outlet and a low pressure steam inlet. The high pressure steam inlet delivers high pressure steam to the ejector. The low pressure steam inlet delivers low pressure steam to the ejector.

An energy-saving gas supply boiler system, comprising: a steam boiler, a flue gas pipeline, a heat exchanger, a steam generator and an ejector. The steam boiler comprises a body, a combusting apparatus, a flue gas outlet, a water outlet and a high pressure steam outlet. The heat exchanger comprises a high temperature flue gas inlet, a medium temperature flue gas outlet, a cooling water inlet and a hot water outlet. Cooling water undergoes heat exchange with flue gas and flows out from the hot water outlet. The steam generator comprises a generator body, a hot water inlet and a low pressure steam outlet. The ejector comprises a high pressure steam inlet, a mixing steam outlet and a low pressure steam inlet. The high pressure steam inlet delivers high pressure steam to the ejector. The low pressure steam inlet delivers low pressure steam to the ejector.

This boiler has a flue in which a reducing agent supplying device and a selective reduction catalyst are provided, a bypass flow path bypassing economizers is provided, and a first closing device partially closing the bypass flow path and a second closing device partially closing the flue are also provided. A plurality of first closing members, serving as the first closing device, are provided along the direction in which exhaust gas flows through the flue at a predetermined spacing in the width direction of the flue. A plurality of second closing members, serving as the second closing device are provided along the vertical direction at a predetermined spacing in the width direction of the flue. The first closing members and the second closing members are arranged so as to be displaced from each other in the width direction of the flue.

A combined heat recovery device includes a high pressure cylinder of a steam turbine; a main steam pipe; a final-stage steam extraction pipe; an additional pipe additionally provided on the main steam pipe; a heat exchanger taking main steam in the main steam pipe as a heat source; a feedwater heater taking discharged steam from the heat exchanger as a heat source; and a steam side regulating valve provided on the additional pipe, configured to regulate main steam in the additional pipe, and capable of controlling a pressure of extracted steam behind the steam side regulating valve to control an outlet temperature of the feedwater heater to reach a preset feedwater temperature.

An apparatus and method for recovery of waste heat in a boiler system, wherein heat from the low pressure steam in the feed water tank, which otherwise would be lost through dissipation, is used for other applications. Particularly, the waste heat energy recovered in the form of low pressure steam can be used to heat make-up water for the boiler system.

A method for improving effectiveness of a steam generator system includes providing air to an air preheater at a mass flow such that the air preheater has a cold end outlet temperature defined by the improved air preheater operating with increased heat recovery (HR) of at least 1% calculated according to the equation: HR=100%?((Tgi?TgoAdvX)/(Tgi?TgoSTD)?1). The method requires either reducing the amount of heat that flows into the air preheater from the flue gas and/or increasing the amount of heat extracted from the flue gas. 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. The method includes extracting heat from the Flue gas to create equipment preheat and/or flue gas stack reheat air with the latter being fed 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.

An apparatus and method for recovery of waste heat in a boiler system, wherein heat from the low pressure steam in a feed water tank, which otherwise would be lost through dissipation, is used for other applications. Particularly, waste heat energy recovered in the form of low pressure steam can be used to heat make-up water for the boiler system.

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.