Balance+ control concept

Paved the way for economic and environmental benefits

The implementation of the ÅF Balance+ adaptive boiler control concept in Thailand’s largest coal power plant, Gheco-One, has led to major efficiency enhancements. The plant’s carbon footprint has been reduced by improving efficiency, and sustainability has been upgraded thanks to a longer service life for the boiler.

The integration of the ÅF Balance+ control concept into the Gheco-One plant has brought numerous advantages. The most important are faster startups with less oil and demineralised water make-up, a higher utilisation rate and improved efficiency. ÅF experts began work on the project in June 2012 with a control performance evaluation. This showed that there was a potential for introducing numerous improvements.

Throughout the project ÅF specialists and plant staff collaborated closely to optimise the plant, and by the time the project was completed in 2014, ÅF’s efforts had supported Gheco-One’s selection as winner of the prestigious ASEAN Energy Awards 2013 in the category “Best Practices – Clean Coal Use and Technology in Power Generation”.

Pressure to improve efficiency

It is the increased use of lower quality fuels together with pressure to reduce emissions and increase efficiency that often is the main driving forces behind the development of new control and optimization strategies in power plants.

The Balance+ concept

ÅF has developed advanced control strategies that facilitate optimal control of power plant processes without the need for time-consuming tuning procedures. The solutions developed by ÅF’s Advanced Process Control team have been incorporated into a single, straightforward control concept called Balance+. This can be customised to meet individual demands for enhancing plant performance and availability.

Adaptive calculation models

The essence of Balance+ is the tool’s process-based calculation models. Any process upsets are measured directly or indirectly and the calculation model then computes what action needs to be taken in order to compensate for these effects. The calculation models are adaptive, so the control response remains optimal even if the process parameters change. Sophisticated calculation models ensure that the process remains stable in the steady state, yet responds quickly to transients, thus minimising any overhand undershoot.

Big savings

The control concept has been successfully introduced in dozens of different kinds of power plants, including drum units and OTU’s of varying sizes. In every case, Balance+ has paved the way for significant economic and environmental benefits in the plants concerned. In Thailand, Balance+ has complemented the plant’s conventional controls with an advanced, process-based control concept. Since Balance+ was installed, overall efficiency gains have been remarkable and plant availability has been much higher. Unit operation has become easier and there is now less need for manual intervention.

World-class efficiency

The plant’s thermal efficiency has improved while variations in feed water and coal flow have decreased. This has resulted in a reduction in average coal consumption, which translates into truly significant annual financial savings. Much more stable combustion process, reduced over-firing and lower excess oxygen levels have also reduced emissions of carbon monoxide, nitrogen dioxide and sulphur dioxide.

Satisfied client

The advantages are numerous for both plant owner and the environment. The plant manager of Gheco-One was so pleased with the results of the Balance+project that, when interviewed, he explained that he had already recommended several of his company’s other plants to implement the same system.

Gheco-One power station is a 660 MWe coal-fired power station in Map Ta Phut, Thailand. It commenced operation in 2012 and supplies power to the state owned Electricity Generating Authority of Thailand, which manages the nation’s entire power transmission network. When first built, the power station increased the Glow Group’s generation capacity in Thailand by approximately 30 percent.

A supercritical plant

Designed to be eco-friendly, the plant operates with supercritical team parameters. This significantly increases steam cycle efficiency, reducing fuel consumption while maximising power generation. However, because of the very high steam pressure and temperatures, a reliable control system is essential to avoid spurious boiler trips that could trigger safety incidents and damage equipment.

With ÅF Balance+ coal savings have been made by 25,200 tonnes annually, and the CO2 emissions reduced by 65,400 tonnes. And the 3.5 MWe reduction in the plant’s own electricity consumption translates into to a CO2 reduction of 23,000 tonnes. In total the annual CO2 reduction due to Balance+ adds up to 88,400 tonnes.