A once-through steam generator or boiler of simple modular construction that utilizes vertical heat transfer tubes, intended primarily for heat recovery in combined cycles. It utilizes a novel method of assembly and operation that make it particularly effective for large combined cycles. Circuit assemblies with a once-through flow path are the key building blocks used to assemble boilers to fit any size gas turbine. They are individually bench fabricated in a horizontal plane. The boiler is manufactured by sequentially stacking individual circuit assemblies in parallel thereby building a circuit module. During the stacking process the inlet and outlet of each circuit assembly are connected to headers to allow the modules to be erected into a heat transfer bundle. For large boilers several transportable circuit modules are interconnected in the field to complete a once-through boiler. Through the use of jumper tubes and a novel maintenance space integrated in the boiler, interconnection of modules in the field is simplified at installation and repair made easy. A novel method of dewatering and drying vertical tube boilers is incorporated. The dewatering method uses stored energy to reverse the flow of water and steam in the boiler thus forcing water out of the tubes. This operating method is important in preventing corrosion of carbon steel tubes, thereby permitting the practical application of carbon steel tubes to vertical tube once-through steam generators.

A turbine overspeed control system for a gas turbine electrical powerplant. The powerplant may employ an aeroderivative gas turbine engine for producing electrical power. The overspeed control system preferably comprises a compression relief system and an air directing system. When an overspeed condition of the gas turbine engine is detected, the compression relief system acts to remove air from a combustion section of the engine. Preferably, the air is removed to the atmosphere. The air directing system operates to ensure that air entering a compressor section of the gas turbine engine does not impinge on the blades of a compressor turbine located therein at the optimum angle. The result of operating the compression relief and air directing systems is a reduced combustor efficiency. Consequently, a reduced amount of hot gases are available to drive the turbines of the gas turbine engine, and the rotational speed thereof decreases.

A microprocessor-based control system for a gas turbine electrical powerplant the microprocessor-based control system controls the startup, operation, and shutdown of the gas turbine electric powerplant. The microprocessor-based control system of the present invention dispenses with the need to utilize relays, timers, or other control hardware. Rather, the microprocessor-based control system employs software that replaces the control hardware, and directly reads the inputs, calculates the control actions, and writes the outputs. The microprocessor-based control system is also in electrical communication with an overspeed control system, provided to ensure that a runaway condition of the gas turbine engine does not occur should the gas turbine engine become disconnected from the speed reducer (gearbox) or generator. Sensors are used to monitor multiple operating conditions of the powerplant. The microprocessor-based control system communicates with the sensors, and activates the overspeed control system if an overspeed condition is detected.

A gas turbine electric powerplant, preferably driven by an aeroderivative turbine engine of split shaft design. The gas turbine engine is coupled to a speed reducer, which is in turn coupled to an electric generator. An engine mount is provided that ensures that the gas turbine engine will remain in proper alignment with the speed reducer and generator, even during the thermal expansion or contraction thereof. Preferably, the components comprising the powerplant are mounted to a common, transportable base, so that the powerplant can be delivered to various locations. An overspeed control system is provided for ensuring that a runaway condition of the gas turbine engine does not occur should the gas turbine engine become disconnected from the speed reducer or generator. Sensors are used to monitor multiple operating conditions of the powerplant. A microprocessor-based control system communicates with the sensors, and is further adapted to activate the overspeed control system if an overspeed condition is detected.

A microprocessor-based control system for a gas turbine electrical powerplant. the microprocessor-based control system controls the startup, operation, and shutdown of the gas turbine electric powerplant. The microprocessor-based control system of the present invention dispenses with the need to utilize relays, timers, or other control hardware. Rather, the microprocessor-based control system employs software that replaces the control hardware, and directly reads the inputs, calculates the control actions, and writes the outputs. The microprocessor-based control system is also in electrical communication with an overspeed control system, provided to ensure that a runaway condition of the gas turbine engine does not occur should the gas turbine engine become disconnected from the speed reducer (gearbox) or generator. Sensors are used to monitor multiple operating conditions of the powerplant. The microprocessor-based control system communicates with the sensors, and activates the overspeed control system if an overspeed condition is detected.