A combined cycle power unit (10) including a gas turbine (16), a heat recovery steam generator (HRSG) (34) to generate steam from an exhaust flow (24) of the gas turbine (16), and a steam turbine (64) driven by the steam generated from the HRSG (34). Steam generated in an evaporator (50) in the HRSG (34) is conveyed through an upstream superheater stage (46a) and a downstream superheater stage (46b) in the HRSG (34). The steam is then conveyed from the downstream superheater stage (46b) to the steam turbine (64). Between the upstream and downstream superheater stages (46a, 46b), the steam flow from the upstream superheater stage (46a) is throttled to a lower pressure to form a reduced pressure steam flow prior to entering the downstream superheater stage (46b) where the steam is reheated to an elevated temperature at the reduced pressure.

The present application provides a once-through evaporator system. The once-through evaporator system may include a number of once-through evaporator sections with a distribution valve and a level sensor and a controller in communication with each distribution valve. The controller provides the distribution valve with a position set point and biases the position set point via a feedforward signal based on a fill level as determined by the level sensor in each of the once-through evaporator sections.

The present application provides a once-through evaporator system. The once-through evaporator system may include a number of enlarged once-through evaporator sections, a first superheater positioned immediately downstream of the enlarged once-through evaporator sections, a second superheater positioned downstream of the first superheater, and an attemperator positioned between the first superheater and the second superheater.

A method comprising the steps of: a) capturing carbon dioxide in a carbon dioxide absorption unit using a carbon dioxide absorption solution; b) feeding the carbon dioxide absorption solution comprising absorbed carbon dioxide and generated in step a) to the high-pressure regenerator of a heat exchange system comprising the high-pressure regenerator and a steam-fired reboiler; and c) supplying low-pressure steam at a pressure ranging from 3.2 to 3.5 kg/cm.sup.2 to the steam-fired reboiler for supplying heat to the high-pressure regenerator wherein, the carbon dioxide absorption solution is heated, thereby producing a steam condensate and a regenerated carbon dioxide absorption solution; characterized in that the method further comprises the step of: d) directly supplying the steam condensate produced in step c) to a de-aerator, thereby producing an aqueous solution suitable for producing steam with an oxygen content lower than 20 ppb.

A method comprising the steps of: a) capturing carbon dioxide in a carbon dioxide absorption unit using a carbon dioxide absorption solution; b) feeding the carbon dioxide absorption solution comprising absorbed carbon dioxide and generated in step a) to the high-pressure regenerator of a heat exchange system comprising the high-pressure regenerator and a steam-fired reboiler; and c) supplying low-pressure steam at a pressure ranging from 3.2 to 3.5 kg/cm.sup.2 to the steam-fired reboiler for supplying heat to the high-pressure regenerator wherein, the carbon dioxide absorption solution is heated, thereby producing a steam condensate and a regenerated carbon dioxide absorption solution; characterized in that the method further comprises the step of: d) directly supplying the steam condensate produced in step c) to a de-aerator, thereby producing an aqueous solution suitable for producing steam with an oxygen content lower than 20 ppb.

The invention relates to the nuclear energy field, including systems for passive heat removal from the pressurized water reactor through the steam generator. The invention increases heat removal efficiency, coolant flow stability and system reliability. The system includes at least one coolant circulation circuit comprising a steam generator and a section heat exchanger above the steam generator in the cooling water supply tank and connected to the steam generator through the inlet and outlet pipelines. The heat exchanger is divided into parallel sections wherein L/D20, L being the half-section length, D being the header bore, and includes an upper and lower header interconnected by heat-exchange tubes, startup valves with different nominal bores are installed on the outlet pipeline. The inlet and outlet pipeline sections of the circulation circuit comprise a set of branched parallel pipelines individually connected to each of the above heat exchanger sections.

Described and illustrated is a method for providing process steam for a process, in particular a process engineering process, using geothermal heat. In order to enable a more climate-friendly, simpler, more efficient and more economical operation, it is provided that the geothermal heat of a thermal fluid heated in a geothermal heat source is used to provide a geothermal steam, that an upgrading steam is used to upgrade the geothermal steam and that during the upgrading the geothermal steam is simultaneously compressed and heated.