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Chemistry of Power Stations

by Rami Elias Kremesti M.Sc., CSci, CEnv, CWEM

 

© 2025 – All Rights Reserved

 

Introduction

 

Besides dealing with the chemical dosing and sampling of the Boiler, which we talked about in the page Chemistry of Boilers, Power Station Chemists also deal with the cooling systems and the quality labs. Some power station  labs are certified to ISO17025. Some of them also keep an eye on the CEMS – the Continuous Emissions Monitoring System. If there is an ISO 14001 EMS – Environmental Management System in place, they have to report their results for compilation in that file too. Chemists on power stations keep an eye on the sewage treatment plant if there is no connection to the local sewer system. They have to make sure that all the chemicals are handled safely. If the power station has a CCUS/FGD system to capture CO2/SOx, they are in charge of the chemistry. Last but not least, they usually deal with the Legionella Management file too.

 

 Chemistry of Boilers

This is basically about minimizing deposits and corrosion in the boiler and steam turbine blades if it is a CCGT or the power station has a large steam turbine. The boiler dumps its steam into the condenser which is cooled by the main cooling tower. Chemicals like ammonia and phosphate are dosed to keep the pH elevated. Oxygen is deadly for boiler running on reducing environments hence the chemist has to keep an eye on the Deaerator which removes traces of dissolved oxygen from the boiler water.

Cooling Tower Chemistry

Cooling towers are fascinating and because of evaporation, they require lots of make up water – unless it is a once through system. We talk about maintaining proper chemistry in cooling towers in our page on Cooling Systems. Sometimes the blowdown from cooling towers is returned to local surface water catchments and needs to be monitored for quality and sometimes even flow. For example, blowdown flow meters might be required to be mCERTS certified.

 

Closed Cooling Water System

Inside the machine hall, where the turbine and condenser are housed, there is normally a closed cooling system to cool all the bearings of the major pumps and sometimes coal feeders. This system is normally filled with demin water and the pH is kept elevated.

 

Chemistry of the FGD

Some dirty coal power stations like Galabovo power Station in Bulgaria and Belchatow in Poland have FGD units – Flue Gas Desulfurization – used to remove SO2 from the flue gas. Limestone is normally crushed and turned into an emulsion and is dosed in an FGD absorber to capture the SO2 and turn it into Gypsum.

 

Quality Lab – ISO 17025

The lab in a power station monitors water, fuel chemistry and sometimes even the insulating oil in the main transformer. Coal fired power station analyze the coal coming in to the power station. We talk about this in detail on our page on coal analysis. For a lab to be accurate and precise, certain standards for quality have to be followed that are laid out in the ISO17015 standard.

 

Chemical Safety File

Most power stations use harsh, corrosive chemicals like acids and bases for regeneration of MBX systems, cooling water treatment, boiler treatment etc. Hence the COSHH file becomes a very important responsibility of the power station chemist.

 

Figure 2. Operators at the Belchatow Power station preparing for unloading hydrochloric Acid which is toxic and dangerous.

CEMS

The continuous emissions monitoring system analyses the flue gas for fossil fuel power stations. The amounts of CO2 emitted, NOx, SOx, and particulates are monitored and recorded for reporting.

CCUS

For those power stations that have CCUS, there are large systems that strip CO2 out of the flue gas. They usually use amines. The chemist has to keep an eye on those systems.

 

ISO 14001 EMS

Power stations that are serious about their environmental impact are ISO 14001 certified.

 

The Sewage Treatment Plant

Many power stations are not connected to local sewers and have the treat the sewage from the operators of the power station. Effluent from the STP needs to be monitored to make sure the STP is working properly.

 

Legionella Management

Anywhere where there is water which is lukewarm with the potential for human contact there is a risk of breathing in the Legionella bacterium. For this reason, the law in the UK, EU and USA requires adherence to strict codes of practice to minimize this risk. We have a presentation on Legionella Management and Control. The Legionella file usually ties in with CDM rules that apply in the UK.

 

In Conclusion

Without power there can be no water and without water there can be no power. This is called the Water-Power nexus and is a fascinating topic. And without a good Chemist at a power station, everything will corrode or scale… there will be accidents… people can get sick.

 

About The Author

Rami Elias Kremesti is a chemist with twenty years of applied experience. He  has worked on power stations around the world. He is chartered with CIWEM, the UK Society for the Environment and the UK Science Council. He loves to read, cook, spend time in nature and his family. He also plays some guitar.