New rating for industrial turbine
Siemens has recently announced a new rating for its SGT-800 gas turbine, the largest of its industrial gas turbines. The new rating is the result of a two megawatt (MW) increase which will reduce life cycle cost for open cycle, CHP and combined cycle plants.
Launched in 1997 as a 43MW machine under the name GTX100, the SGT-800 currently produces 45MW with an electrical efficiency (ISO) in open cycle of 37percent.
The new rating is 47MW at 37.5percent efficiency. The combined cycle performance has also improved from 64MW with an efficiency of 53percent to 66MW with an efficiency of 54percent with dual-pressure heat recovery steam generator (HRSG).
Underlying this enhancement is a proven operating record since commercial introduction and a comprehensive testing program, resulting in redistribution and saving of cooling air.
During a comprehensive ‘hot section mapping’ carried out by Siemens in 2003, over 1900 thermo-crystals were attached to the hot gas path components, and thermal paint, thermocouples and pressure taps were used to verify the temperature and pressure distribution in the turbine area.
The result showed that cooling air could be redistributed and saved, giving a more uniform temperature profile for some hot section components, thus reducing stresses due to temperature gradients.
This saving, together with a 1.4percent additional airflow from the compressor, is now used to increase power and improve efficiency.
Four components in the gas turbine have been modified, but fully interchangeable between the 45MW and the 47MW rating. The combustor exit temperature, which impacts hot section component life, will remain the same.
The enhancement has been running in one single plant since November 2006 (5500 Equivalent Operating Hours, June 2007). The plant operates in continuous duty on natural gas and has only been stopped for washing, filter exchange and a scheduled follow-up borescope inspection at 4100EOH. The results of the inspection were in line with all expectations.
The enhancement can be offered to new and existing customers and orders are already booked by both categories.
The first two new units of SGT-800 gas turbines with 47MW output will be delivered to Condamine in Queensland, Australia. Siemens’ customer is Austrian Energy & Environment (Australia), who are EPC contractor for a 140-MW turnkey combined cycle plant to be built in Queensland, Australia, for end customer Condamine Power Station Pty. Ltd.
Power from the plant will be used for grid support, selling power both into the national power pool, and under contract to various off-takers.
For more information, visit http://w1.siemens.com/en/entry.html
