Abstract

The paper presents several aspects regarding the optimization of the operation for a mixed cycle gas turbine, Titan 130S type,

installed at S.C. CET S.A. Bacau, during the warm season. The optimization entails the partial loads operation and has been done

using the multicriterial analysis, taking into consideration the operation restrictions required for this type of gas turbine. The

criteria that regard this analysis are: thermal energy requirements, the global efficiency in high cogeneration, the electric energy

price, the emission level of NOx and CO2. These criteria have been applied on several operating conditions of gas turbine. As a

result of this analysis has been chosen the optimum operating regimen that corresponds to a predefined forecast period.

These operating conditions took into account the need to provide the necessary heat forecast thermal energy to provide hot water

for domestic and non-domestic clients from Bacau city during summer by energy and financial efficiency conditions with a low

level of pollutant emissions. Two operating restrictions were considered for the gas turbine: the first one is a technical type and

the second one regards the admissible level for NOx emissions. The technical restrictions refer to maximum number of turbine

start-ups in this case daily number of start-ups and annual number of start-ups for this type of turbine being limited. This

limitation is due to the equipment’s wear during the turbine start-up drive and exceeding the allowed number of start-ups leads to

premature wearing and to the growth of the maintenance expenses. The restrictions regarding the NOx emissions level derive from

the installation of a SoLoNOx combustion system for this type of turbine. The SoLoNOx combustion system ensures a low level

of NOx emissions and the considered restriction is due to this type of combustion start-up operation at loads higher than 60% of

this type of gas turbine rated power. This system uses powerful swirl injectors, which produce an intense circulating area for the

mix-fuel in the combustion chamber with low oxygen level so as the combustion takes place at a low temperature blocking the

formation of thermal NOx.