Control systems and methods suitable for combination with power production systems and methods are provided herein. The control systems and methods may be used with, for example, closed power cycles as well as semi-closed power cycles. The combined control systems and methods and power production systems and methods can provide dynamic control of the power production systems and methods that can be carried out automatically based upon inputs received by controllers and outputs from the controllers to one or more components of the power production systems.

Aspects of the present disclosure relate to steam cycle methods, systems, and apparatus for efficiently reducing carbon footprints in plant systems. In one aspect, a cycle is conducted in a plant system to collect CO.sub.2. In one aspect, a cycle is conducted in a plant system to recycle energy. The plant system includes one or more of a power production system, a refining system, and/or a petrochemical processing system.

Control systems and methods suitable for combination with power production systems and methods are provided herein. The control systems and methods may be used with, for example, closed power cycles as well as semi-closed power cycles. The combined control systems and methods and power production systems and methods can provide dynamic control of the power production systems and methods that can be carried out automatically based upon inputs received by controllers and outputs from the controllers to one or more components of the power production systems.

A diffuser nozzle for a gas turbine engine includes a housing disposed about a nozzle axis and extending between a first nozzle end and a second nozzle end. The housing defines a nozzle duct. A plurality of walls is disposed within the nozzle duct. The plurality of walls subdivides the nozzle duct into a plurality of duct sections. The plurality of walls further defines a plurality of axially-extending duct segments of the nozzle duct such that within a first axially-extending duct segment, the duct cross-sectional area of a first duct section of the plurality of duct sections is greater than the duct cross-sectional area of each other duct section and within a second axially-extending duct segment, the duct cross-sectional area of a second duct section of the plurality of duct sections is greater than the duct cross-sectional area of each other duct section.

The present invention provides methods and system for power generation using a high efficiency combustor in combination with a CO.sub.2 circulating fluid. The methods and systems advantageously can make use of a low pressure ratio power turbine and an economizer heat exchanger in specific embodiments. Additional low grade heat from an external source can be used to provide part of an amount of heat needed for heating the recycle CO.sub.2 circulating fluid. Fuel derived CO.sub.2 can be captured and delivered at pipeline pressure. Other impurities can be captured.

Offshore systems and methods may be configured for offshore power generation and carbon dioxide injection for enhanced gas recovery for gas reservoirs. For example, a method may include: providing an offshore facility including a gas turbine, and a gas separator; producing a produced gas from a gas reservoir to the offshore facility; combusting the produced gas in a gas turbine to produce power and a flue gas; at least partially removing nitrogen from the flue gas in a gas separator to produce a carbon dioxide-enriched flue gas and a nitrogen-enriched flue gas; compressing the carbon dioxide-enriched flue gas in a gas compressor to produce a compressed gas; and injecting the compressed gas from the gas compressor into the gas reservoir, wherein 80 mol % or more of hydrocarbon in the produced gas is combusted and/or injected into the gas reservoir.

The present disclosure relates to systems and methods wherein a dilute hydrocarbon stream can be oxidized to impart added energy to a power production system. The oxidation can be carried out without substantial combustion of the hydrocarbons. In this manner, dilute hydrocarbon streams that would otherwise be required to undergo costly separation processes can be efficiently utilized for improving the power production system and method. Such systems and methods particularly can utilize dilute hydrocarbon stream including a significant amount of carbon dioxide, such as may be produced in hydrocarbon recovery process, such as enhanced oil recovery or conventional hydrocarbon recovery processes.

Sweep-based gas separation processes for reducing carbon dioxide emissions from gas-fired power plants. The invention involves at least two compression steps, a combustion step, a carbon dioxide capture step, a power generate step, and a sweep-based membrane separation step. One of the compression steps is used to produce a low-pressure, low-temperature compressed stream that is sent for treatment in the carbon dioxide capture step, thereby avoiding the need to expend large amounts of energy to cool an otherwise hot compressed stream from a typical compressor that produces a high-pressure stream, usually at 20-30 bar or more.

Methods and systems for CO.sub.2 separation for low emission power generation in combined-cycle power plants are provided. One system includes a gas turbine system that stoichiometrically combusts a fuel and an oxidant in the presence of a compressed recycle stream to provide mechanical power and a gaseous exhaust. The compressed recycle stream acts as a diluent to moderate the temperature of the combustion process. A boost compressor can boost the pressure of the gaseous exhaust before being compressed into the compressed recycle stream. A purge stream is tapped off from the compressed recycle stream and directed to a CO.sub.2 separator configured to absorb CO.sub.2 from the purge stream using a potassium carbonate solvent.

The invention relates to a method for operating a gas turbine power plant, including a gas turbine, a HRSG following the gas turbine, an exhaust gas blower, and a carbon dioxide separation plant which separates the carbon dioxide contained in the exhaust gases and discharges it to a carbon dioxide outlet, the gas turbine, HRSG, exhaust gas blower, and carbon dioxide separation plant being connected by means of exhaust gas lines. According to the method a trip of the gas turbine power plant includes the steps of: stopping the fuel supply, switching off the exhaust gas blower, and controlling the opening angle of a VIGV at a position bigger or equal to a position required to keep a pressure in the exhaust gas lines between the HRSG and the exhaust gas blower above a minimum required pressure. The invention relates, further relates to a gas turbine power plant configured to carry out such a method.