Gas-turbine

Hydraulic applications for gas-turbine power plants

Duplomatic Oleodinamica has gained during the years a specific experience in the energy sector by developing and examining some projects in cooperation with sector technicians for the applications of both special components and of gas-turbine dedicated systems which are realized and certified in compliance with the ATEX 94/9CE European Directive for the Area 2 (Category 3).

Adjusting servo-cylinders
They are currently used for 80-160 and 250 MW power plants. Their function is the activation of valves aimed at controlling the flow of the liquid or gaseous fluid; their task is therefore fundamental in order to guarantee positioning precision and reliability. In order to be up to such requirements, the oil regulation occurs through a high-dynamic servo-valve with a transducer on the loop closure, which assures a centesimal positioning precision to the system. Just consider that 1 millimeter error causes a waste of some MW of electrical energy.

On-off cylinders
They are used for the start of the valves stopping the fuel flow in order to guarantee the safety conditions of the plant; the system foresees a set of disc springs and a circuit which allows the fast discharge of the starting oil. The component has to guarantee the valve complete closure within about 0.2÷0.3 seconds independently of any emergency condition.

IGV servo-cylinders
The function performed by this actuator is the handling of the Inlet Guide Vanes system: such system regulates the vanes of the first fixed stage of the compressor of a gas turbine, making the vanes rotate in order to change the air flow rate incoming into the machine and therefore also the combustion of the flame into the boiler. The basic features required to this double-effect actuator are rigidity and precision; the closed loop control system is formed by a high-dynamic servo-valve and a position transducer.

Blow-Off actuators
The function performed by this system is the handling of the blow-off valves of the gas turbines. The blow-off valves protect the main compressor of the gas turbine against possible pumping events or against possible vibrations into the combustion chamber due to undesired transients. The main feature of this actuator is to ensure the required torque at the valve closure but, even more, to guarantee, at any moment and in any operating condition, the emergency opening of the valve itself. The function of the above-mentioned systems is included in the gas turbine enclosure, where the turbine adjustment is performed. This is therefore classified as an “explosion hazardous area” and all the above-mentioned actuators are realized and certified according to the ATEX European Directive for the Area 2.

Power control units
The experience in the design and realization of hydraulic systems in the different energy and industrial sectors allows Duplomatic to supply the whole system by using its own components. The function of the control unit for the power supply of the servo-cylinders requires the use of extremely reliable signaling and emergency components which are manufactured according to strict specifications agreed with the customer. Duplomatic has also the possibility to self-certify the whole plant in compliance with the PED Certification.