Abstract: A once-through steam generator having single pass non-split fluid flow upper furnace circuitry with a one to one connection of tubes of the lower furnace spiral or vertical tube assembly being connected to the vertical tubes of the upper furnace assembly to prevent steam water separation and provide a fully drainable flow circuit.

Abstract: The water flow circuit for a heat recovery steam generator includes both a low pressure circuit and a high pressure circuit. Both circuits are designed for once-through flow and both include evaporators with rifled tubing. A pressure equalizing header may be located between the evaporator and superheater and orifices may be located at the inlet to the evaporator for flow stability.

Abstract: In a once-through steam generator, a separating bottle (25) is inserted between the evaporator (22) and the superheater (23). To purify the water/steam circuit, a greater quantity of water than is necessary is conveyed through the evaporator (22) via a feed pump (20). The water quantity is measured in such a way that wet steam enters the separating bottle (25). This water fraction, together with all the impurities contained therein, is separated in said bottle and is drawn off via a blowdown line (29). On the occasion of overfeeding, a conditioning agent is metered to the water, in order to reduce the volatility of the substances to be separated.

Abstract: In once-through flow steam generators including a burner for fossil fuels and having a vertical gas flue with essentially vertically disposed tubes, inlet ends of the tubes are connected to an inlet header and outlet ends of the tubes are connected to an outlet header. According to the invention, a pressure-equalization tube branches off from each tube at the same height. The tube is connected to a pressure-equalization vessel. The height H is chosen in such a way that in the case of an individual tube being more strongly heated between the inlet header and the branching-off point of the pressure-equalization tube, the mass flow through the individual tube increases as compared to a mean value of the heating of all of the tubes.

Abstract: A once-through steam generator has a vertical flue formed of tubes which are oriented vertically and which are connected in parallel for guiding a flow of flow medium therethrough. The tubes have a surface structure on an inner wall surface which causes flow turbulence and eddy currents in the flow medium. The surface structure includes first and second, mutually superimposed, contrary ribbings. The first ribbing encloses an acute angle with the tube axis, and the second ribbing extends parallel to the tube axis. The first ribbing forms an onflow flank angle with the tube wall which is flatter than a flow-off flank angle. Elevations of the ribbings rise at least 0.7 mm above the tube wall surface. A mass flow density of the medium in the tubes is adjusted as a function of the inner tube diameter, by maintaining the mass flow density below a predetermined limit curve.

Abstract: A gas and steam turbine plant has a gas turbine producing exhaust gas, a water-steam loop in which water is preheated at a given high pressure and subsequently evaporated, a steam turbine in the water-steam loop, and a steam generator through which the exhaust gas flows for generating steam for the steam turbine. The steam generator has at least one preheater connected to the water-steam loop and a high-pressure heater connected downstream of at least one preheater. The water-steam loop has a partial loop connected parallel to the at least one preheater outside the steam generator for carrying an adjustable throughput quantity. A heat exchanger is disposed in the steam generator in the vicinity of the at least one preheater for removing usable heat.

Abstract: A reheat steam temperature control system that utilizes the separate components of a reheater and a reheat heat exchanger to generate hot reheat steam. The reheater uses the fluidized bed as its source of heat while the reheat heat exchanger uses main steam as its source of heat. A bypass control valve is operated to divert the required amount of main steam to the reheat heat exchanger depending on operating conditions. Should the temperature of the hot reheat steam be too low, additional main steam is delivered to the reheat heat exchanger. Conversely, should the temperature of the hot reheat steam be too high, the amount of main steam delivered to the reheat heat exchanger is reduced. Attemperators are used within both the reheating circuit and the main steam circuit to temper the fluctuations of their respective steam.

Abstract: The invention relates to a process for starting up a heat exchanger system for the generation of steam accommodated in a hot gas line, in particular in an exhaust gas line, conveniently in a waste heat boiler, for instance downstream from a gas turbine, for instance for starting up a circulation system steam generator or a continuous flow (once-through) steam generator, conveniently a natural or forced circulation boiler or once-through boiler, in particular a preheater/evaporator/superheater system provided with a start-up heat exchanger upstream via which the supply of feed medium, in particular water or steam, is effected, and which on start-up dispenses first hot steam and finally water to the heat exchanger system, so that the initially pressureless, void heat exchanger system substantially heated to hot gas temperature is continuously brought to its operative state and its operating temperature, as well as a corresponding heat exchanger system.

Abstract: A continuous-flow steam generator includes a vertical gas flue for connection to an outlet conduit of an apparatus emitting hot gas, such as a gas turbine. An evaporator heating surface in the vertical gas flue has an inlet header, an outlet header and tubes connected between the inlet and outlet headers. The tubes form an upper tube segment having an upper segment end and a lower segment end as well as a lower tube segment having an upper segment end and a lower segment end. The upper segment end of the upper tube segment merges with the upper segment end of the lower tube segment.

Abstract: A condensate return tank for storing and condensing water in a closed loop steam system is provided having a generally cylindrical body closed at each end and a float valve comprising a ball attached at one end to a lever arm which is itself attached at its other end to a pivotal fitting secured to the inner surface of the tank. The tank is arranged, and an opening is provided on the surface of the horizontally disposed tank, adjacent one end and spaced therefrom by a distance permitting manual entry into the tank. The float valve is mounted on the inner surface of the end so as to be accessible from the opening. A cap rests on and closes the opening.

Abstract: A method of operating a once-through steam generator having a first evaporator heating surface formed of a tube wall of a combustion chamber, and a second evaporator heating surface connected in parallel to the first evaporator heating surface at a water inlet side thereof, the second evaporator heating surface being located in a convection chamber post-connected to the combustion chamber at a flue-gas outlet side thereof downstream from a superheating surface as viewed in a flow direction of flue gas, includes opening a water regulating valve preconnected to the second evaporator heating surface in the flow direction of the feedwater, if a predetermined value of a mass flow of the feedwater into the once-through stem generator is exceeded, so as to initiate a partial mass flow of the feedwater into the second evaporator heating surface; and closing the water regulating valve again, if the predetermined value fails to be attained, so as to terminate the partial mass flow of the feedwater into the second evapo

Abstract: An evaporating apparatus includes an evaporator (E) for converting a liquid into vapor and a preheater (2) for heating the liquid before it is fed to the evaporator (E). A pump (6) for feeding the liquid to the preheater (2) and another pump (8) for pressurizing the liquid passing from the preheater (2) to the evaporator (E) are provided, where the former maintains the liquid at a saturation pressure with respect to a temperature slightly higher than a saturation temperature (t.sub.o) at the preheater outlet, and the latter serves to raise the liquid pressure to a saturation pressure with respect to a desired evaporation temperature (t.sub.2). Rate of flow of a heating medium for the preheater (2) is controlled so that its temperature (t.sub.w3) is slightly higher than a liquid preheater outlet temperature (t.sub.ex). Thus, in the preheater (2), the liquid temperature (t.sub.ex) is maintained lower than saturation temperature (t.sub.o), ensuring a greater amount of heat transfer by subcool boiling.

Abstract: The steamer comprises a first heating chamber (5) intended to generate wet steam from supplied water, and a second heating chamber (6) arranged between the first heating chamber (5) and the cooking chamber (2) and used for heating the wet steam coming from the first heating chamber (5). The temperature of the steam introduced in the cooking chamber (2) by means of the distribution means (4) is regulated by control device (9). In the steamer, the temperature of the steam supplied to the cooking chamber (2) may be continuously varied while reducing to a minimum the negative influence of limestone.

Abstract: A method of controlling the steam quality leaving parallel circuits of once-through steam generators using untreated feedwater having high solids concentration wherein control valves in each circuit are actuated by signals generated by the electrical conductivities of the water phase leaving each circuit and the feedwater entering the generator unit.

Abstract: A method and apparatus for recovery of heat from the flue gas of the combustion furnace of a steam boiler or power generation plant uses a heat pump heat extracted from a lower temperature point in the system to a higher temperature point in the system. The flue gas is passed through an economizer to preheat the boiler feed water. The flue gas then passes to a direct contact gas cooler where a second stream of cooling water extracts heat from the flue gas. The second stream of cooling water is passed through the evaporator of the heat pump to heat a refrigerant. The refrigerant is compressed and then condensed in thermal contact with the boiler feed water to heat it before it enters the economizer. In a second embodiment a power generation plant has a steam turbine and an auxiliary vapor turbine. The flue gas is passed through a gas cooler and gives up heat to a stream of cooling water.

Abstract: A heater comprising two separate tube nests of which one (29) heats the circulating water by condensation and supercooling and the other (39) heats a partial flow of this water by the desuperheating of steam. Steam is admitted through pipe (16). The foregoing partial flow of water comes from the desuperheating zone of a heater located downstream and is admitted through a manifold (41). Pipes (39) are wound round a central drum (43).

Abstract: An apparatus for controlling the drum water level of a drum boiler prevents the boiler system from being tripped off which would otherwise be caused by an excessive fall in the drum water level immediately after the start of load runback, by increasing the real feed water flow rate in such a manner that a feed water flow rate demand signal obtained from the drum water level deviation is corrected by a feed water flow rate increment signal obtained from the amount of load reduction (load demand--load reference after load runback) at the time of load runback. In addition, the fact that the drum water level stops falling and starts to rise is detected, and the feed water flow rate demand signal is adjusted so as to take a medium value between the real feed water flow rate and the real main steam flow rate, thereby preventing the boiler system from being tripped off which would otherwise be caused by an excessive rise in the drum water level.

Abstract: A coupling controller opens a dump valve at the outlet of a heat recovery steam generator when such generator is to be coupled to another generator being in operation with a steam turbine on a common header. The controller gradually permits pressure build-up until the pressure at the outlet of the new generator matches the pressure behind the header. The controller also responds to critical conditions in the superheater as well as in the high pressure drum of the generator in the operation.

Abstract: A fluid feeding apparatus can gradually elevate the head of a fluid of steam/liquid mixture by recirculating the fluid through a centrifugal pump of moderate output and an injector. The fluid ejecting out of the nozzle of the injector will entrain a steam/liquid mixture of high latent heat from a fluid intake port so that the heat energy of the condensate from the other sources can be recovered and reused. By virtue of providing a gas intake port for the injector, the fluid can be supplemented with gas wherever needed. Due to the substantial volume of the gas phase in the reservoir, the internal pressure of the reservoir will not increase drastically because of the dampering effect of the gas phase. Thus only a centrifugal pump of moderate output is needed for implementing the recirculation of the elevation of the pressure in the reservoir.

Abstract: A method of utilizing the energy of a high pressure condensate stream including passing steam at an elevated pressure in indirect heat exchange with a material to be heated, collecting a condensate product condensed from the steam of the heat exchange step at an elevated pressure, passing the condensate directly to a steam stripping step at essentially the same pressure at which the condensate was collected and reducing the pressure of the condensate while simultaneously contacting the condensate with a material to be stripped in the stripping step.

Abstract: Boiler feedpump net positive suction head (NPSH) control is performed in a heat recovery steam generator including a deaerator inserted between steam turbine condensate and steam boiler. To this effect apparatus is provided responsive to temperature at the output of the deaerator, to fluid flow therefrom, and to temperature at the input of the boiler feedpump for providing a signal representative of the anticipated suction head pressure, and the NPSH margin is derived by comparison with actual pressure to control the pegging valve, or other heat source control to the deaerator.

Abstract: An apparatus and method of supplying feedwater to a forced flow boiler or the like as described. A positive displacement pump having a plurality of discrete pumping elements is arranged to pump feedwater from an inlet to the boiler. The pump includes bypass valves which, when open, disable the pumping action of an associated pumping element. Control means responsive to the demand for water in the boiler are arranged to disable a selected number of the pumping elements so that the rate of water supplied by the remaining elements, if operated continuously, would just exceed that required. The control means is further arranged to disable at least one of the remaining pumping elements on a periodic basis so that the ratio of time that the element is enabled to the time for one period multiplied by the water flow rate supplied by said element, if operated continuously, equals the difference between the total demand for water and the rate supplied by the pumping elements enabled on a full-time basis.

Abstract: A control system for controlling the location of the nucleate-boiling region in a fluid heated steam generator comprises means for measuring the temperature gradient (change in temperature per unit length) of the heating fluid along the steam generator; means for determining a control variable in accordance with a predetermined function of temperature gradients and for generating a control signal in response thereto; and means for adjusting the feedwater flow rate in accordance with the control signal.

Abstract: An economizer is connected to the highest point of the evaporator by an evaporation pipe provided with a valve, in order to operate a forced flow-through steam generator at low costs. During re-filling of the economizer with a small quantity of feed water, the steam formed during shutdown due to stored heat, can escape into the vapor space above the water level when the valves are open.

Abstract: Energy and water are recovered from flue gases by cooling them to a temperature sufficiently below the acid dew point temperature by contact with an aqueous stream so as to recover the sensible heat and to reduce the water content of the flue gases by about 50%. The water by which the aqueous stream is enriched is subsequently flashed off to cool the stream back to its original temperature and the water vapor is then compressed to generate a higher temperature vapor stream which is condensed to recover the water and extract heat. The aqueous stream is continuously enriched with material such as calcium carbonate to control the pH sufficiently as to avoid substantial corrosion due to acidic gases removed from the flue gases and the aqueous stream is purged continuously or periodically to remove compounds such as chlorides, calcium sulphates, and fly ash solids picked up from the flue gases.

Abstract: A once-through steam generator has both radiant and convection sections. The flue gases discharged from the convection section are passed through a wet scrubber to remove both sulfur oxides (SO.sub.x) and particulate matter. The feedwater to the convection section has its temperature controlled by the temperature of the flue gases discharged from the convection section, reducing the temperature of the feedwater by the use of a feedwater exchanger, as the convection section progressively fouls due to particulates in the flue gases. An additional heat exchanger upstream of the feedwater exchanger and convection section which scavenges additional heat from the wet scrubber liquids while the temperature of the flue gases into the scrubber are lowered to a temperature equal to or less than the water dew point temperature of the flue gases entering the scrubber.

Abstract: Installation for generating superheated steam from raw water containing salt using preheaters for heating the raw water. The last preheater, as seen in the flow direction of the raw water, is followed via a control valve by a decompression cylinder. Part of the raw water evaporates and the vapor is withdrawn from the dome of the decomposition cylinder by a compressor which compresses and heats it and discharges it as superheated steam.

Abstract: The inventive combination provides for a profitable and efficient utilization of low-pressure waste heat in conjunction with medium-pressure steam. The combination of mechanical and thermodynamic compression for the generation of superheated low-pressure steam is a method that has better results regarding energy and cost than any other known configuration.

Abstract: A boiler water trip system comprises a flow transmitter for sensing a flow of water into a boiler, a pressure transmitter for sensing a pressure of steam entering a first stage of a turbine powered by the boiler, a unit power transmitter for sensing the power generated by the turbine, a feeder water temperature transmitter and a drum level transmitter for sensing the level of water in a steam drum connected to the boiler. Function generators are connected to the pressure and unit load transmitters for obtaining a measure of flow out of the boiler. The higher of the two flow values are compared with the feed water flow to the boiler to generate an error signal which is integrated. The integrated error signal corresponds to a calculated boiler water level amount. If the boiler water level rises above or falls below set limits and, simultaneously, a drum level rises above or falls below said amounts as determined by the drum level transmitter, a tripper is activated to trip the boiler.

Abstract: A heat exchanger in which the main component is formed of a plurality of elongated strips of rigid heat conductive material. The strips are generally transversely aligned and wound into a coil formation in which each of the surfaces of each strip is disposed in facing relation to the opposite surface of an adjacent strip in the coil. Each pair of facing surfaces is ridged to provide passage defining portions and force transmitting portions with certain of the strips having both end edges thereof sealingly secured to the corresponding end edges of an adjacent strip so as to define a longitudinal fluid passage having a coil formation other of the strips have both end edges thereof disposed out of sealing engagement with corresponding end edges of the adjacent strip so as to define a transverse fluid passage.

Abstract: A water outlet pipe leading to a feed water tank is connected to a separator disposed downstream of an evaporator. A heat exchanger and a first control valve are disposed in the water outlet pipe, the valve being influenced by the level in the separator 20. In the heat exchanger heat is transmitted from the water flowing out of the separator to the feed water flowing to the heating surfaces of the vapor or steam generator. Between the heat exchanger and the first control valve, a bypass pipe branches from the water outlet pipe and contains a second control valve which is also influenced by the level in the separator. The bypass pipe leads into a condenser. A considerable proportion of the water leaving the separator is discharged via the bypass pipe to the condenser as a result of the pipe branching off upstream of the first control valve.

Abstract: Steam generator for generating steam from feedwater of lower quality, having heating surfaces formed of tubes welded to one another directly or through bridges, a plurality of the tubes being connected in parallel in respective groups at the feedwater and steam sides of the generator including a first feedwater circulatory system with water of lower quality, a second feedwater circulatory system with water of higher quality, a first part of the group of tubes connected in parallel at the feedwater side of the generator being connected in the first feedwater circulatory system, and a second part of the group of tubes connected in parallel at the feedwater side of the generator being connected in the second feedwater circulatory system, the tubes of the second part of the group of tubes at the feedwater side being distributed between the tubes of the first part thereof.

Abstract: Method of improving the permissible load-varying speed of a once-through steam generator having a water separating vessel connected between a heating surface of the once-through steam generator and a heating surface of a superheater with a valve connected into a steam delivery line extending from the water separating device to the superheater heating surface, the valve being openable during start-up and shut-down of the once-through steam generator, which includes closing the valve to such a limited extent, depending upon the temperature of the water separating vessel, that the temperature of the water separating vessel corresponds to boiling temperature of feedwater supplied to the once-through steam generator at a pressure at which a transition occurs with respect to pure once-through operation, and device for performing the foregoing method.

Abstract: System for separating water and steam in a continuous steam generator in which a separating device is interposed after the evaporator to separate steam from water coming from the evaporator. The steam goes to a second heating surface. Water is stored in the separating device and withdrawn through a discharge line for recirculating. A second discharge line above the first discharge line leads to the second heating surface. Control valve means control the discharge of water through the second discharge line. This system permits use of a highly heated second heating surface by effecting cooling of the heating surface during start-up and preventing damage to the heating surface material, and by providing the superheater surface for maintaining a high live steam temperature at partial load.

Abstract: The forced-flow steam generator is provided with a control means for controlling the amount of water fed to the evaporator. The control means includes a controller which receives a load-dependent signal and an actual value signal from a temperature measuring means. The steam generator includes an injection line which communicates at a point downstream of the temperature measuring means. The controller may be connected directly to a valve in the injection line in order to regulate the amount of water which is bypassed around the evaporator or may be connected directly to the feedwater supply to maintain a constant flow to the evaporator during injection of water.

Abstract: The temperature of a monotube boiler is controlled by apparatus that regulates the water flow only. Primary water is supplied to the inlet end of the boiler tube in accordance with the heat furnished to the boiler, and secondary water is injected into the boiler tube at a plurality of points spaced along the tube in accordance with the temperature of the steam as determined by a sensor located just upstream of the outlet end of the tube. One of the injection points, termed the feedback point, is located adjacent to and upstream from the temperature sensor. Feedback water injected at the feedback point has an immediate effect on the temperature sensor which is effective to maintain the steam at a substantially constant output temperature during steady state operation over a wide range in the heat furnished to the boiler, and during transient operation from one state to another caused by rapid and large changes in the heat furnished to the boiler.

Abstract: A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. A condenser receives the spent steam from the steam turbine for converting it into condensate. The steam generator includes a deaerator for receiving the condensate flow from the condenser and for storing it in a storage portion, a feedwater pump for directing the stored condensate through a first heat exchange tube whereby heat is transferred from the gas turbine exhaust gases to the fluid, a main drum for receiving and storing the heated fluid and a second heat exchange tube for heating the fluid by the gas turbine exhaust gases into superheated steam to be supplied to the steam turbine.

Abstract: The steam generator which may be a forced-flow type, a drum boiler type or exhaust-gas type has at least one of the operational magnitudes, i.e. firing intensity, feedwater flow rate, gas flow rate and the like, regulated in accordance with temperature variations in the region of the economiser. The temperature variation is subjected to a retardation and the resulting signal is superimposed on the control signal (L) for the operating magnitude.