How GT13E2 can enhance power generation efficiency in Russia

Vattenfall’ Berlin Mitte Power Plant.

Specifically engineered for the needs of the Russian market conditions, the GT13E2 upgrade brings performance improvements in engine output and efficiency, and this has been possible with a number of improvements. To increase the power output and the turndown capability of the GT13E2, the first 16 stages of the proven compressor used in the GT26 have been integrated into the GT13E2 engine. Three variable guide vanes allow a wider range of turn down at higher compressor efficiency as compared to the previous compressor with single variable guide vane row, and the mass flow of the engine is increased by approximately 10%.

Operational flexibility

The combustion system has been upgraded to further enhance the emission behavior and the operational flexibility of the GT13E2 by implementing the Advanced EnVironmental (AEV) burner. The design of the four-slot swirler is aerodynamically optimized with a higher throughput of combustion air as compared to the existing GT13E2 EV design. As a result the number of burners is reduced, from 72 EV burners to 48 AEV burners. The AEV burner system can be permanently operated over the entire load range with low NOx emissions.

A robust combustion is obtained by the presence of the mixing section, the flame front being insensitive to variations of air temperature and humidity as well as natural gas composition and gas temperature. Therefore, the GT13E2 upgrade with AEV burner has enhanced fuel and operational flexibility.

Increased power output

With the new upgrade, there is 202.7 MW / 38% gross engine performance at generator terminals, i.e. a 10% power output increase, and +0.2%-pt efficiency improvement. The combined cycle plant performance is also boosted, gaining 48 MW in a 2-on-1 plant configuration, with high net plant efficiency. The improved part-load performance permits to generate significant fuel savings.

The 2012 upgrade offers better efficiency at high ambient conditions, especially in typical hot climate countries. The range of air inlet cooling options (evaporative cooling, fogging, high fogging) help to keep the power output characteristics flat over a wide range of ambient temperature. The AEV burners improve the environmental performance of the machine, and the GT13E2 is now able to run with 25 vppm NOx emission in the 100% down to 70% GT load range.

Other improvements and benefits

The GT13E2 allows fast and wide variations in the fuel gas quality. In case of decreasing fuel gas supply pressure, fast fuel switch over from gas to oil operation ensures uninterrupted stable power supply, which can be executed while the machine remains at full load.

The start-up time can be reduced to 15 minutes from the standard 25 minutes through increased start-up power during the rotor acceleration phase combined with a smart ramp-up load control, allowing for higher loading gradients within a selected load range. The use of three rows of variable guide vanes in the GT13E2 upgrade offers superior part load performance, and ensures that the gas turbine exhaust temperature remains high over a wide range of GT operating loads.

The upgrade also features flexible operation modes and power augmentation options, and a GT13E2 based combined cycle power plants can easily be fitted with large supplementary firing, allowing high power supply flexibility, and increased power vs. heat production flexibility for CHP plants.

Simplified fuel system

Small refinements and improvements have also been made to increase the ease of maintenance. Pre-engineered functional modules have been introduced for the auxiliary systems, and the fuel system has been simplified. Together with the reduction in the number of parts (e.g. from 72 EV burners down to 48 AEV burners), the duration of the maintenance work and effort is reduced.

The GT13E2 upgrade achieves increased simple cycle performance, improved part load efficiency, high ambient temperature performance / low ambient temperature capability, and reduced emissions levels and maintenance requirements.