A fluid recirculation system includes an arrangement of a flow control valve located to receive a flow of fluid from an inlet. The system further comprises an economizer inlet mixing device located to receive the flow of hotter fluid from the arrangement of the flow control valve and from a cooler feedwater stream. An economizer inlet mixing device located upstream of an economizer in a supercritical pressure boiler includes a sparger assembly through which a flow of fluid from the waterwall outlet is received, an inlet through which a flow of fluid from a feed stream is received, and a wave breaker assembly through which an outlet stream from the economizer inlet mixing device is directed.

A fluid recirculation system includes an arrangement of a flow control valve located to receive a flow of fluid from an inlet. The system further comprises an economizer inlet mixing device located to receive the flow of hotter fluid from the arrangement of the flow control valve and from a cooler feedwater stream. An economizer inlet mixing device located upstream of an economizer in a supercritical pressure boiler includes a sparger assembly through which a flow of fluid from the waterwall outlet is received, an inlet through which a flow of fluid from a feed stream is received, and a wave breaker assembly through which an outlet stream from the economizer inlet mixing device is directed.

In one embodiment, an exhaust heat collecting system of collecting exhaust heat in a fluid treatment system. The fluid treatment system includes a fluid path to convey at least an operating fluid or a cooled fluid among first and second heat source fluids, the operating fluid and the cooled fluid. The fluid treatment system further includes a fluid treatment module including an expansion module, a power generator and a condenser for the operating fluid, or including a heat absorbing module and a heat releasing module for the cooled fluid. The exhaust heat collecting system includes a water path to heat water by using the condenser or the heat releasing module, and a heater to heat the water from the water path by using the first or second heat source fluid or the operating fluid to produce the water to be used as hot water or to produce steam.

In one embodiment, an exhaust heat collecting system of collecting exhaust heat in a fluid treatment system. The fluid treatment system includes a fluid path to convey at least an operating fluid or a cooled fluid among first and second heat source fluids, the operating fluid and the cooled fluid. The fluid treatment system further includes a fluid treatment module including an expansion module, a power generator and a condenser for the operating fluid, or including a heat absorbing module and a heat releasing module for the cooled fluid. The exhaust heat collecting system includes a water path to heat water by using the condenser or the heat releasing module, and a heater to heat the water from the water path by using the first or second heat source fluid or the operating fluid to produce the water to be used as hot water or to produce steam.

Methods and systems for controlling steam distribution within a kiln. A kiln system includes a muffle, a boiler, a steam sparger coupled to the boiler and located with the muffle. The steam sparger is configured to output steam at a proximal end that is different from output steam at a distal end by less than a threshold amount, and a material introduction device configured to move material from a proximal end to a distal of the muffle, the material introduction device located a predefined distance from the steam sparger.

Methods and systems for controlling steam distribution within a kiln. A kiln system includes a muffle, a boiler, a steam sparger coupled to the boiler and located with the muffle. The steam sparger is configured to output steam at a proximal end that is different from output steam at a distal end by less than a threshold amount, and a material introduction device configured to move material from a proximal end to a distal of the muffle, the material introduction device located a predefined distance from the steam sparger.