Abstract: A once-through stem generator includes a vertical gas flue having a total given height, a bottom, a lower part having a height equal to less than 70% of the total given height, an upper part, and fossil fuel burners disposed on the lower part. The lower and upper parts are formed of gas-tight tube walls with tubes. The tubes of the lower part rise obliquely, while the tubes of the upper part are vertical. The lower part has a lower end limited by the bottom, and the upper part has an upper end limited a partition of the vertical gas flue, by a cross-sectional restriction of the tube walls, or by a lower edge of a heating surface within the vertical gas flue.

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 forced-flow once-through boiler for variable supercritical pressure operation comprises burners, water-wall tubes constituting the surrounding walls of a furnace and which are themselves made up of banks of vertical generating tubes for simultaneous upward flow, and a convection-heating type evaporator mounted between the outlets of the water-wall tubes and a water separator.

Abstract: An improved system of transferring heat energy from a high temperature fluid to a low temperature fluid is described. A countercurrent heat exchanger is employed in which heat transfer fluids undergo one or more thermodynamic transitions at various pressures by employing conventional heat exchangers having additional components. It has been determined that by employing this system of the present invention under a critical choice of design parameters, a substantially greater amount of heat energy can be transferred per unit area of the heat exchanger than was possible by conventional techniques.