Boilers are an essential element of industrial processes. They need to be reliable and kept in good working order. With skyrocketing fuel and energy costs, maintaining the reliability and consistent performance of a boiler while minimising energy costs is challenging for any industrial plant. This is regardless of the number and size of the boiler or what commercial activity or item is produced at the end of the day.
Since boiler systems are constructed primarily of carbon steel and the medium for heat transfer is water, the potential for corrosion is high. The build up of corrosion can result in a forced shutdown of the boiler and the industrial process. Boiler water treatment is therefore essential for both the operating efficiency and equipment life. The feedwater must be pure, and the re-circulating boiler water and condensate must be kept scrupulously free of contaminants and dissolved oxygen.
"The given pH level in boilers is 9.5 but using the new formulation the pH level drops to between 8.3 and 8.6. This usually implies a higher rate of corrosion, but even with this lower pH level the corrosion was ten times smaller than corrosion at the higher pH level."
Blachownia Institute of Heavy Organic Synthesis, Poland
The basic approach used to keep the corrosion at bay, is to chemically treat the water in the boiler feed system. Up until now, the newest technologies have used combinations of amines and hydrazine to create a protective film and reduce the formation of deposits on the internal heat exchange surfaces. This improves the heat exchange in both the boiling and condensation processes of the boiler and decreases corrosion and erosion.
However, the polyamines used so far have limited thermal resistance and start to decompose at around 300 degrees centigrade. This means that considerably large amounts of the chemical treatment have to be used to build up and renew the protective amine layer. Moreover, maintaining the right level of acidity and alkalinity (pH values) throughout the boiler system becomes a problem when the polyamines start to decompose.
The five partners involved in EUREKA E! 2426 BOILTREAT project set out to research and develop more thermostable amines which start to decompose at higher temperatures, of just over 500 degrees centigrade. Their thinking was that if they could successfully come up with a water treatment using more thermostable amines, it would offer exceptional protection against corrosion and deposit formation. In turn, it would result in higher boiler efficiency and prolong the life of the equipment. Consequently, by improving water quality less contaminant waste is released into the environment.
One of the particular objectives was to pick up on a commercially available amine-based water treatment called Kontamina. This is popular water conditioning treatment available and widely used in Poland and Romania, in thermal electric power stations and heat generating plants with various types of boilers.
Two of the project partners, the Blachownia Institute of Heavy Organic Synthesis in Poland and the Rohm and Haas company in France researched and developed the amines and produced batches of new formulations. Scientists at the Lithuanian Energy Institute conducted the investigations on how the high-temperature resistant amines would affect the corrosion of steel pipes. The Fachhochschule Bonn-Rhein-Sieg in Germany was responsible for the analysis and development of standard procedures.
The most promising formulation underwent a series of industrial tests alongside the traditional water treatment, for the best part of a year, in electric and thermal power stations in Poland. The INCD-Icemenerg Research and Development National Institute for Energy in Romania carried out the final evaluations on corrosion speed and deposit formation in the boiler water, and analysed the metal samples from the boiler.
The results spoke for themselves and were written up as scientific research papers. "The new formulation is much better and much cheaper," says Dr. Marian Kozupa of the Blachownia Institute team. "There was ten times less corrosion than the traditional Kontamina application. And, less of the formulation was needed, ten to thirty percent less than the amount of traditional treatment."
Boiler manufacturers generally state that boilers should be run at higher, more alkaline pH levels to slow down corrosion. "The given pH level in boilers is 9.5 but using the new formulation the pH level drops to between 8.3 and 8.6. This usually implies a higher rate of corrosion, but even with this lower pH level the corrosion was ten times smaller than corrosion at the higher pH level," explains Dr. Kozupa.
"The success of this project required close cooperation between different research organisations in Europe manufacturers and end users. Without EUREKA it wouldn't have been feasible."
Blachownia Institute of Heavy Organic Synthesis, Poland
The project partners have named the new water treatment Kontamina Plus. The treatment is already being used in power stations in Romania and the partners have been successful in signing a licence agreement for its production, with Ekochem, a company based in Gliwice, Poland.
The Institute has also been awarded a distinction for the water treatment in The product of the future competition held by the Polish Agency for Enterprise Development. Power plants in Poland are still wary of using the new treatment, and the partners are looking for endorsements from boiler manufacturers.
The main partners are convinced that the success of the project lies in the cooperation with other partners. "Working in a EUREKA project was a great opportunity for us," says Dr. Kozupa. "The success of this project required close cooperation between different research organisations in Europe manufacturers and end users. Without EUREKA it wouldn't have been feasible to do it. The project required a lot of research which we wouldn't have been able to afford by ourselves."