The existing natural gas fired combined cycle unit was built in 1993 and has an electricity output of 60 MW and district heating output of 60 MW. The configuration is a single shaft arrangement with a gas turbine with HRSG, a steam turbine and 1 generator in common for the gas turbine and steam turbine.
The combined cycle unit shall be modified in order to use the existing steam turbine and generator without operating the gas turbine, i.e. by steam supply to the steam turbine from the new bio-mass boiler. However, in order to cover peak load electricity demands, the modification shall be made in such a way that the possibilities to operate the combined cycle in the original mode remains.
The primary modification required for operation without the gas turbine is the installation of a clutch in the shaft line between the gas turbine and the generator. A number of other modifications of the combined cycle unit will also be required, for instance:
— Modify or replace the ST SSS clutch for start up of the ST — Generator unit from stand still;
— Rebuild of the lube oil system which presently is one common system for GT and Generator;
— Adaption of the GT and ST control systems to the new operational modes.
It is intended to have one single contractor for the modifications required for the combined cycle unit. This includes all services and deliveries from design and engineering up to and including commissioning support etc. required for the modification of the unit.