Designing Supercritical CO2 Power Plants

The supercritical CO2 power cycle is one of the most promising power technologies. It is not by chance though, because carbon dioxide (CO2) has a unique combination of attributes, such as a low critical temperature, an environmentally natural origin, a high standard of safety and a low cost. Carbon dioxide is also thoroughly studied, therefore there is sufficient information surrounding it. But on the other hand, the supercritical CO2 cycle has a high energy conversion factor, such as high thermal efficiency.
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Which gas turbine is the best for my combined cycle power plant conversion?

combinedcyclesThe goal of this test case is to find the gas turbine necessary to produce 58 MW of total net power for the conversion of a steam turbine to a combined gas-steam cycle while providing the highest level of cycle thermal efficiency.

The exhaust gases from the gas turbine are used to heat up steam through three HRSGs (Heat Recovery Steam Generators) in series. The steam is then used in the studied steam turbine which is comprised of two “cylinders” in series.
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Retrofitting – Why Turbine Seals Are Important

Wreckage of 330 MW Turbine-generator from LP rotor burst
Wreckage of 330 MW Turbine-generator from LP rotor burst

Whether it is caused by a “poor” design, extreme operating conditions or even too much deterioration, turbine failures can occur. In order to help prevent these it is necessary to perform regular maintenance on all parts of the machine and control the conditions at which the turbine is operating at any moment in time as well as performing repairs and retrofits to keep the pieces in good shape.

One way to improve steam turbine efficiency is through better seals. However, when designed incorrectly they can create significant damages and performance losses in the turbine. Sealing steam turbine rotors presents several challenges. Any gap between the rotor and the packing lets the steam escape, dropping the pressure and wasting energy. If the packing ring is too tight, however, the rotor will rub, which creates localized hot spots. Continue reading “Retrofitting – Why Turbine Seals Are Important”

Retrofitting – When Steam Turbines Age

Steam-Turbine
Steam-Turbine

Statistics show that as a power plant reaches its rated lifetime, the number of its forced outages begins to grow substantially, and its reliability and availability fall.

Simultaneously, in the operation process the turbine’s efficiency lowers more and more, even though it is partially restored at overhauls.

It is possible to find steam turbines that have successfully operated for 40 – 50 years or more. Lately, power equipment lifetime extension has substantially gained in its scope and acquired much more serious significance. Continue reading “Retrofitting – When Steam Turbines Age”