A dual fluid heat exchange system is presented that provides a stable output temperature for a heated fluid while minimizing the output temperature of a cooled fluid. The heated and cooled fluids are brought into thermal contact with each other within a tank. The output temperature of the warmed fluid is maintained at a stable temperature by a re-circulation loop that connects directly to the mid portion of the tank such that the re-circulated fluid flow primarily warms only a re-circulation section of the tank. The other, lower flow rate, section of the tank may be positioned so that it has a cooler temperature and thus serves to increase the efficiency of the heat exchange by extracting extra heat energy out of the cooled fluid before it leaves the tank. Alternatively, the low flow rate section of the tank may be warmer than the re-circulated section, and thus allow the re-circulated section to be cooler than the output temperature of the warmed fluid.

Methods and systems generate steam for injection in a well to facilitate oil recovery. Water is preheated at a central processing facility, transported to a well pad by hot water lines, and converted to steam by a steam generator at the well pad.

Apparatus and method to wet start the HRSG and combined cycle in the fastest time with minimum thermal stress. This wet start provides the earliest possible cooling steam during acceleration, reducing stress in the superheater, reheater and steam turbine. The gas turbine is started and loaded to full power in the fastest possible time without holds. A once-through HRSG filled with saturated boilerwater including the superheater generates dry steam during acceleration. Start apparatus positions the dryout zone in each superheater tube, controls surge swell, ensures uniform pressure rise, and controls the steam temperature. The superheater generates temperature controlled steam to cool the tubes while heating headers. Superheater and reheater tubes and headers start at saturation and increase to operating with minimum differential temperatures. The superheater evaporating boilerwater supplies constant low temperature dry steam to start the steam turbine without the use of attemporators.

Heat recovery steam generator comprises a casing, low-pressure evaporator coils, preheater booster coils upstream thereof and feedwater heater coils downstream thereof, a water-to-water heat exchanger having low and high temperature paths; a first conduit from the preheater to the high-temperature path, and a second conduit from the feedwater heater to the preheater. A conduit can extend from feedwater heater to low-pressure evaporator. A conduit can extend from the water-to-water heat exchanger to the feedwater heater. High-pressure economizer coils can be upstream of the preheater, with a conduit exiting the feedwater heater to the high-pressure economizer. Additional coils can be upstream of the high-pressure economizer. The feedwater heater can comprise first and second sections, or first, second and third sections; or more sections. The connections among the various components and sections can be near their upstream and downstream faces.

A method of heat recovery from bulk solids includes introducing the bulk solids into an inlet of a heat exchanger for indirect heat exchange with water as the bulk solids flow, by gravity, from the inlet to an outlet of the heat exchanger, pumping the water into subcritical heating heat transfer elements within the heat exchanger for indirect heat exchange with the bulk solids to heat the water and thereby provide heated, pressurized water, and flashing off steam from the heated, pressurized water.

A method of heat recovery from bulk solids includes introducing the bulk solids into an inlet of a heat exchanger for indirect heat exchange with water as the bulk solids flow, by gravity, from the inlet to an outlet of the heat exchanger, pumping the water into subcritical heating heat transfer elements within the heat exchanger for indirect heat exchange with the bulk solids to heat the water and thereby provide heated, pressurized water, and flashing off steam from the heated, pressurized water.

The steam boiler system comprises a steam boiler comprising a burner and a chimney for exhausting flue gases, a feedwater line for leading feedwater to said steam boiler for producing steam, a steam line leading from said steam boiler to at least one application heat exchanger for feeding steam to said application heat exchanger, said application heat exchanger for heating an application fluid, and a condensate line leading away from said application heat exchanger for recuperating condensate from said application heat exchanger. An economizer heat exchanger is provided in said chimney, wherein at least one of said condensate return line and said feedwater line circulates through said economizer heat exchanger for allowing at least one of said condensate and said feedwater to be in heat exchange relationship with the flue gases for simultaneously cooling the flue gases while heating at least one of the condensate and the feedwater.

A thermal power plant is described comprising a solar collector field and a heat storage to allow the use of the thermal energy collected by the solar field with a time delay for the production of electricity in the steam power plant.

A solar thermal power system includes a solar receiver, and a thermal energy storage arrangement having thermal energy storage fluid to be circulated through the solar receiver to store thermal energy. The system includes a multistage steam turbine operable on variable pressure steam generated by a steam generator arrangement, by utilizing the thermal energy storage fluid. The arrangement includes an economizer section, an evaporator section, and a superheater section communicably configured to utilize the heat of the hot thermal energy storage fluid to generate and supply the variable pressure steam to the turbine. The system includes a recirculation line configured around the economizer section to recirculate the heated water to an inlet of the economizer section, increasing pressure range of the variable pressure steam in the arrangement.

A solar thermal power system includes a solar receiver, and a thermal energy storage arrangement having thermal energy storage fluid to be circulated through the solar receiver to store thermal energy. The system includes a multistage steam turbine operable on variable pressure steam generated by a steam generator arrangement, by utilizing the thermal energy storage fluid. The arrangement includes an economizer section, an evaporator section, and a superheater section communicably configured to utilize the heat of the hot thermal energy storage fluid to generate and supply the variable pressure steam to the turbine. The system includes a recirculation line configured around the economizer section to recirculate the heated water to an inlet of the economizer section, increasing pressure range of the variable pressure steam in the arrangement.