Chemicals in the water cycle of a power plant

Power plants are inherently very complex systems. The challenge for power plant operators is to ensure maximum safety in all the processes of the water cycle. All components, including the piping systems, must conform to the highest safety and reliability standards. The piping systems in power plants, in particular, are exposed to excessive loads when transporting the acids and alkalis required for water treatment. Presented in the following are several processes in which aggressive chemicals are used and which can cause corrosive damage in pipe networks.

“Georg Fischer Piping Systems has developed high quality plastic pipes, which provide a superior resistance to corrosion, incrustation, abrasion and chemical resistance, ultimately resulting in reduced costs for planning, operation and maintenance. Even after years of use, there is no incrustation or corrosion, only smooth bore pipes with the same low energy consumption to keep the flow moving.”
-Christina Granacher

Cooling tower make-up water treatment

These are compact systems used to treat all types of raw water (well water, river water and seawater) by means of flocculation, sedimentation and decarbonization.
In the classic method, inhibitors are added to the cooling water to protect the pipes and heat exchangers against corrosion. Biocides or chlorine dioxide are deployed to control biofilms. By dosing acids and alkaline solutions, the pH of the water can be kept to low corrosion levels.

Boiler feed water

The core process of power plants involves heating water and converting it into steam, which is why water quality and corrosion protection are particularly important aspects in this process. The boiler feed water is freed of salts as well as O2 and CO2 by means of ion exchangers or reverse osmosis. Diverse chemical additives (such as e.g. oxygen binding agents, corrosion inhibitors, caustic soda, ammonia water or hydrazine) are used depending on the type of boiler connected.

Liquid waste processing and flue gas cleaning

In the liquid waste processing systems of power plants, the process-related effluents are treated prior to discharge. This is achieved with gypsum dewatering, solids reduction and the removal of heavy metals.

Flue gases are cleaned in a complex process, which requires systems that dose the ammonia water or urea used to remove nitrogen oxides. Also required are lime skids and diverse dewatering processes.

Waste water treatment

The objective of waste water treatment is to remove waste content from the water and to restore the natural quality of the water. In order to comply with legal limits, pH regulation of the plant waste water is realized by the dosed addition of precipitants or substrates.

The future belongs to plastic piping systems

In the past, metal piping systems were used in power plants, where they proved to be effective. However, many features associated with these systems are still considered a given, e.g. high maintenance costs, especially for corrosion protection. Georg Fischer Piping Systems has developed high quality plastic pipes, which provide a superior resistance to corrosion, incrustation, abrasion and chemical resistance ultimately resulting in reduced costs for planning, operation and maintenance.

Compared to metal systems, plastic systems have the added advantage of needing minimal maintenance.

High demands and best solutions

As an experienced partner, Georg Fischer Piping Systems offers ideal solutions for power plant projects. The system solutions include pipes, fittings, valves, measurement and control technology as well as jointing technologies that consulting engineers find very convincing. In addition, the company offers a wide range of services, like consulting, technical and cost optimization, mechanical and chemical advice, training in theory and practice (jointing and installation) and much more. Customers can choose from over 20 different systems, fitting best to their processes and a service life of at least 25 years. GF Piping Systems is the only company which provides complete solutions within industrial plastics piping sector worldwide.

Plastic solutions save time and money

It makes no sense to compare only the engineering and material costs of metal against plastic piping systems. If you look at the total cost of installation, implementation, documentation, maintenance and repair, you get a totally different picture. The chemical resistance of plastics is much higher than that of metals. Even after years of use, there is no incrustation or corrosion, only smooth bore pipes with the same low energy consumption to keep the flow moving and this without major maintenance efforts.

One of the key benefits of the total plastic solutions offered by GF Piping Systems is their high safety margin. The safety and reliability of these solutions have been confirmed by independent certified test laboratories.

Steritec AG, Switzerland, compared the overall installation costs of GF plastic piping systems (PVDF) to stainless steel (316L) systems. In the end, plastic was rated about one-third better, and this even despite the fact that the price of plastic was higher than metal. Overall, plastic piping systems are much easier and also faster to install. With pre-fabrication, the installation time can be reduced even further. The study clearly demonstrated that plastic piping systems offer the "best cost of ownership". The combination of their technical properties and their cost saving potential makes plastic piping systems a true alternative to traditional systems with measurable added value.

The company consistently maps its customers' processes and offers solutions specifically aligned to them. For over 50 years, GF Piping Systems has been developing plastic components that are 100 percent reliable, long-lived and compliant with customer demands. "For the power plant sector as well as for other sectors, we offer a complete system design in the same corrosion-free material, thus allowing our customers to benefit from the lowest repair and maintenance costs. Our materials provide maximum chemical resistance and warrant consistent performance over their entire lifetime," confirms Christina Granacher, Head of Global Market Development & Innovation, Georg Fischer Piping Systems.

Christina Granacher

Since 2009, Christina Granacher, Head of Global Market Development and Innovation, has led a global team which manages eight market segments: energy, water treatment, water and gas distribution, chemical process industry, building technology, food & beverage, shipbuilding and microelectronics. She joined Georg Fischer Piping Systems in 2004 as global market segment manager for the chemical process industry and power plants. She holds a degree in plastic engineering.