Abstract: Method and system for adjusting a measured reheat outlet steam temperature (“RPV”) to approximate a reheat outlet steam temperature setpoint (“RSP”) in a boiler. An RPV is compared to an RSP. If the RPV is less than the RSP and a position of a fuel nozzle tilt (“TILTPV”) is below a high limit of the fuel nozzle tilt (“TILTHIGH”), the TILTPV is increased while a flow rate of a secondary flue gas recirculation (“SFGRPV”) is kept constant. If the RPV is less than the RSP and the TILTPV is at the TILTHIGH, the SFGRPV is increased. If the RPV is greater than the RSP and the SFGRPV is greater than a low limit of flow rate of the SFGR (“SFGRLOW”), the SFGRPV is decreased, while the TILTPV is kept constant. If the RPV is greater than the RSP and the SFGRPV is at the SFGRLOW, the TILTPV is decreased.

Abstract: Disclosed herein is a once-through evaporator comprising an inlet manifold; one or more inlet headers in fluid communication with the inlet manifold; one or more tube stacks, where each tube stack comprises one or more substantially horizontal evaporator tubes; the one or more tube stacks being in fluid communication with the one or more inlet headers; one or more outlet headers in fluid communication with one or more tube stacks; an outlet manifold in fluid communication with the one or more outlet headers; and a plurality of flow control devices to dynamically control the fluid flow to a respective inlet header.

Abstract: Disclosed herein is a once-through evaporator comprising an inlet manifold; one or more inlet headers in fluid communication with the inlet manifold; one or more tube stacks, where each tube stack comprises one or more substantially horizontal evaporator tubes; the one or more tube stacks being in fluid communication with the one or more inlet headers; one or more outlet headers in fluid communication with one or more tube stacks; and an outlet manifold in fluid communication with the one or more outlet headers.

Abstract: Disclosed herein is a system comprising an evaporator; a water reservoir in fluid communication with the evaporator; the water reservoir being located upstream of the evaporator; and a first steam drum in fluid communication with the evaporator; the first steam drum being located downstream of the evaporator; where the water reservoir is operative to supply feedwater to the evaporator while maintaining a predetermined water level in the first steam drum.

Abstract: Disclosed herein is a system comprising an evaporator; a water reservoir in fluid communication with the evaporator; the water reservoir being located upstream of the evaporator; and a first steam drum in fluid communication with the evaporator; the first steam drum being located downstream of the evaporator; where the water reservoir is operative to supply feedwater to the evaporator while maintaining a predetermined water level in the first steam drum.

Abstract: A method for exercising control over the final predefined superheat outlet steam temperature and for exercising control over the final predefined reheat outlet steam temperature from a circulating fluidized bed steam generator having a furnace volume embodying at least superheat surface, a multichambered backpass volume embodying at least superheat surface within one chamber of the multichambered backpass volume and at least reheat surface within another one of the multichambered backpass volume, a first circulatory fluid flow path operative as an evaporative steam loop, and a second circulatory fluid flow path operative as a superheat steam-reheat steam loop and including a saturated steam segment, a superheat steam segment, a reheat steam segment and an economizer segment.

Abstract: The final reheater in a circulating fluidized bed combustion system which is located in a separate fluidized bed heat exchanger and which would be subjected to hot solids without any cooling after a blackout or turbine is cooled by bleeding a portion of the steam from the superheater outlet through a normally closed high pressure drop valve and into the final reheater. A valve downstream from the final reheater is also opened to permit flow.

Abstract: A combustion subsystem with a circulating fluid bed boiler (12) having a pantleg configuration. The boiler includes front (22) and back (24) walls with external fluid bed heat exchangers (48) integral therewith. In addition to the conventional fuel inlets (54) which provide for entry of fuel into the side walls of the boiler through conduits connected to the seal pots (36) of solids recycle cyclones (30), supplemental fuel inlets (63, 66, 70, 72) are provided on the front and back wails of the boiler through the fluid bed heat exchangers or between adjacent fluid bed heat exchangers. The invention improves combustion efficiency in large boilers by reducing the theoretical mixing length within the boiler.