Cheng process
The Cheng process , also known as Cheng Cycle or STIG ( Steam Injected Gas Turbine ) process, is a process used to improve the efficiency of gas turbines , which are used to provide heat and electrical energy .
The residual heat generated by a gas turbine is used in the Cheng process to generate steam in a waste heat boiler connected behind the turbine , which can be fed back into the combustion chamber of the gas turbine. The higher mass flow in the turbine due to the addition of steam ensures an increase in output, and the efficiency of the gas turbine is improved through heat recovery . The steam is released into the environment with the flue gas. The feed water used to generate steam escapes with the turbine exhaust gases and has to be replaced, but it can also be recovered from the exhaust gas through condensation (as in the "Aquarius" system from the Ukrainian manufacturer Zorya-Mashproekt ).
The Cheng cycle process is very flexible, as it is possible to change the amount of steam fed back into the turbine so that the increase in efficiency can be adapted to the needs at hand. The residual heat of a gas turbine can therefore be used to increase the electrical power or to provide process heat , depending on the requirements .
The steam must be of feed water quality in order to avoid damage in continuous operation ( corrosion and contamination by salts). Therefore, because of the high costs, the Cheng cycle is currently used less for continuous operation than for short-term increases in performance. (E.g. in the paper industry with significant fluctuations in the demand for electricity and heat)
literature
- Richard A. Zahoransky: Energy technology: Systems for energy conversion. Compact knowledge for studies and work. 456 pp., Vieweg + Teubner Verlag, 2004. ISBN 978-3-528-13925-4