Abstract: A steam generator system comprising a coal-fired steam generator in fluid communication with a regenerative air preheater. The steam generator being adapted to receive a flow of heated combustion air exiting from the regenerative air preheater and to discharge a flow of hot flue gas to the regenerative air preheater. The regenerative air preheater adapted to receive a flow of cool air in counter flow to the flow of hot flue gas and to provide a heat exchange between the cool air and the hot flue gas to convert the cool air into the heated combustion air exiting to the steam generator. The steam generator system further comprising a first flow of heated air, diverted from the flow of heated combustion air, and routed through a source of pulverized coal to form a mixture comprising heated air and pulverized coal. The mixture being directed, by means of a fan positioned downstream of the source of pulverized coal, to the steam generator for combustion therein.

Abstract: A regenerative air preheater leakage recovery system comprising a coal-fired steam generator in fluid communication with a regenerative air preheater. The regenerative air preheater adapted to provide a heat exchange between a flow of cool air and of hot flue gas to convert the cool air into the heated combustion air exiting to the steam generator. A combination of seals for effecting at least one plenum that is in fluid communication with the heated combustion air flow and the flow of hot flue gas relative to the regenerative air preheater. A captured flow of leakage, diverted from the flow of heated combustion air and directed by means of a fan to re-enter the regenerative air preheater at a location substantially separate from where the flow of cool air is received in the regenerative air preheater to be further heated therein and exit as the flow of heated combustion air.

Abstract: A sorbent addition system for a steam generator system having a boiler, an air preheater, a scrubber, an air duct providing fluid communication between the air preheater and the boiler, a first flue gas duct providing fluid communication between the boiler and the air preheater, and a second flue gas duct providing fluid communication between the air preheater and the scrubber. The sorbent addition system comprises a calciner having a calciner exhaust which provides fluid communication with either the first or second flue gas ducts. A limestone addition subsystem and a fuel addition subsystem are in fluid communication with the calciner.

Abstract: A method for increasing the efficiency of a steam generator system including a boiler and a regenerative air preheater. The method including determining a reduced rate of acid accumulation in the preheater which may be achieved by injecting an SO3 neutralizing additive material into flue gas generated by the boiler. A new maximum allowable clean condition pressure drop is calculated based on the reduced rate of acid accumulation. Modified heat exchange element baskets are created having an increased heat transfer efficiency, compared to conventional heat exchange element basket assemblies, and a maximum allowable clean condition pressure drop substantially equal to the calculated new maximum allowable clean condition pressure drop. The conventional heat exchange element basket assemblies are replaced with modified heat exchange element basket assemblies. When the boiler is operating, the additive material is added to the flue gas.

Abstract: An air preheater for use with a boiler which discharges a flow of flue gas containing SO3 comprises a housing having oppositely disposed hot and cold ends. The hot end includes an air outlet duct, having a combustion air duct and an excess air duct, and a flue gas inlet duct, the combustion air duct and flue gas inlet duct are in fluid communication with the boiler. The cold end includes an air inlet duct and a flue gas outlet duct in fluid communication with the atmosphere. A rotor rotatably mounted in the housing includes an air sector in fluid communication with the air inlet and outlet ducts and a flue gas sector in fluid communication with the flue gas inlet and outlet ducts. A plurality of heat exchange element basket assemblies rotate through the air and flue gas sectors, with the heat exchange element basket assemblies absorbing heat from the flow of flue gas in the flue gas sector and discharging heat to the flow of air in the air sector.

Abstract: The thermal performance of the heat transfer element assemblies for rotary regenerative air preheaters is enhanced to provide a desired level of heat transfer and pressure drop with a reduced weight. The heat transfer plates in the assemblies have spaced apart dimples for maintaining plate spacing and oblique undulations with the undulations on adjacent plates preferably extending at opposite oblique angles. The dimples may be on every other plate and alternate between the two sides of the plates or they may be on every plate and all extend to the same side.

Abstract: The flue gas temperature coming from an air preheater to a particulate collection device such as an electrostatic precipitation or fabric filter is reduced to improve the operation of the particulate collection device. This may be done by reducing the exit flue gas temperature from the air preheater or reducing the temperature after exiting. In one embodiment, air in excess of that needed for combustion is passed through the air preheater with the heated excess air either being dumped or used for a variety of purposes in the plant. A particular embodiment involves segmenting the air outlet side of a rotary regenerative air preheater and withdrawing the excess air from the segment where the dust loading is the lowest. Further, additional cooling of the flue gas can be provided by reducing the quantity of primary air that typically bypasses the air preheater and then providing other ways to control the primary air temperature to the pulverizers.

Abstract: Heat transfer elements for rotary regenerative heat exchangers are formed with spacing ridges or notches having flow-disrupting indentations in the peaks of the notches formed at selected intervals to project into the flow channels. These projections interrupt the boundary layer and cause turbulence and mixing to enhance the heat transfer. Various methods of forming the indentations are disclosed.

Abstract: Heat transfer elements for rotary regenerative heat exchangers are formed with spacing ridges or notches having flow-disrupting indentations in the peaks of the notches formed at selected intervals to project into the flow channels. These projections interrupt the boundary layer and cause turbulence and mixing to enhance the heat transfer. Various methods of forming the indentations are disclosed.

Abstract: A heat exchange element for an air preheater has first and second heat transfer elements arranged to form channels for the passage of a heat exchange media having a main flow direction. Each of the heat exchange plates has parallel straight ridges and flats between the ridges. The ridges alternate to extend transversely from opposite sides of each heat transfer plate. The ridges of the adjacent plates are oriented obliquely in opposite directions relative to the main flow direction and contact each other solely at points of intersection of the ridges.

Abstract: A heat transfer element for a rotary regenerative preheater has first and second heat transfer plates. The first heat transfer plate defines a plurality of generally equidistantly laterally spaced apart parallel straight notches. Each notch has adjacent double ridges extending transversely from opposite sides of the first heat transfer plate. Undulations extend between the notches. The second heat transfer plate is adjacent the first heat transfer plate and defines a plurality of generally equidistantly laterally spaced apart parallel straight flat sections. Undulations extend between the flat sections and the flat sections are spaced apart a distance generally equal to the lateral spacing of the notches. The notches of the first heat transfer plate are in contact with the flat sections of the second heat transfer plate to define channels therebetween.

Abstract: A fouling sensing system monitors fouling of a rotary regenerative preheater having a housing and a rotor rotatably mounted therein. An emitter for emitting energy is positioned at one of the faces of the rotor and emits energy through the rotor. A sensor is positioned at the other face of the rotor for receiving the energy and generating an output signal indicative of the intensity of the energy.

Abstract: A rotary regenerative air preheater has a rotor which is divided into sectors by diaphragm plates. Mounted between these diaphragms are support gratings which support the heat exchange baskets with there being at least two circumferentially adjacent full-wrapper baskets on each support grating. The gratings include radial seals which extend axially into the spaces between these adjacent baskets to provide a seal to minimize circumferential fluid flow. Attached to the radial seals at the axial ends of the rotor are seal strips which form a seal with the sector plates on the rotor housing thereby forming a double seal to minimize cross flow between the gas side and the air side.

Abstract: Ceramic blocks which may be catalyst coated having gas flow channels therethrough are supported in a metal framework to form a removable basket for a rotary regenerative air heater. The blocks are supported between compressed packing material with individual rows being supported at one inlet edge and the opposite outlet edge by Z-plates.

Abstract: A heat pipe air preheater includes a multiplicity of heat pipes arranged in a plurality of superposed planar rows inclined relative to the horizontal, the rows of heat pipes including a first group of rows inclined at a first inclination angle and a second group inclined at a second inclination angle. Means are provided for removing collections of soot or other particulate matter from the evaporator ends of the heat pipes, the rows of the first group being disposed on one side of these means while the rows of the second group are disposed on the other side, the rows of the two groups converging in the direction of the heat pipe condenser ends.

Abstract: A hollow metallic envelope 10 of a finned cast recuperator tube is cast with preformed interior fins 12 and exterior fins 16 integral therewith. A sand core 30 is formed about the preformed interior fins 12 with portions of the fins 12 protruding outwardly from the sand core, and a sand mold 40 is formed to a cavity for receiving the sand core 30 with the preformed exterior fins 16 embedded in the sand mold with portions of the fins 16 protruding therefrom into the cavity. The sand core 30 is placed into the sand mold 40 in spaced relationship therewith so as to provide a clearance space 50 between the sand core 30 and sand mold 40 into which the portions of the interior fins 12 and exterior fins 16 extend. Molten metal is poured into the space 50 which upon cooling solidifies to form the envelope 10 with the interior fins 12 and exterior fins 16 fused integrally therewith.

Abstract: A tubular recuperative heat exchanger (10) is adapted for transferring heat from a hot gas stream having a temperature of 1200 F. flowing over the outside surface of the heat exchange tubes (12) to a cold gas stream flowing therethrough. A turbulator (22) is disposed within each heat exchange tube (12) to improve convective heat exchange. The turbulator (22) is coated with a material having a higher absorptivity than that of the underlying surface of the turbulator. Further, the inside surface (24) of the heat exchange tubes (12) may be coated with a material having a higher emissivity than that of the underlying inside surface of the heat exchange tubes.

Abstract: A recuperative tubular heat exchanger comprised of a plurality of tube-bundle heat exchange modules (20) stacked in a spaced array and interconnected by U-shaped, open-end header conduits (30) to form a serpentine flowpath through which a fluid to be heated is passed in heat exchange relationship with a heating fluid passing in cross flow over the tube bundle modules. The interconnected modules together with the header conduits form an integral assembly which is free to slide on support beams (26) so as to float within the housing (12) of the heat exchanger in response to the thermal deformation of the tube bundle modules.

Abstract: A structural support for a module of a concentric tube type recuperative heat exchanger. A plurality of support beams 18 extend laterally across each module to support upper and lower tube sheets 22-24 independent from surrounding housing structure. The support beams are attached to the tube sheets by pivotal hangers 26 that permit relative movement therebetween, while said support beams are themselves supported at their ends on lateral shelf units affixed to the housing that surrounds each module.