Editorial - VGB PowerTech Journal 3/2016
Power plant chemistry today
The tense situation, in which the conventional power plants are at the moment, should be well-known to the reader of the VGB PowerTech journal. However, what are the consequences for power plant chemistry? Which tasks do the chemists fulfil in the operation of the power plants, today and in the future?
During the last decades, the power plant chemists have made a major contribution to the development of our recent modern and emission-reduced coal-fired power plants. The building up of knowledge concerning the formation of oxide protection layers in the water-steam cycle, the development of the flue-gas desulphurisation plants and the reduction of nitrogen oxides in the flue gas by catalysts should be mentioned as examples. The detailed history was described e.g. by my predecessor Prof. Dr.-Ing. Herwig Maier in his editorial “All power plant is chemistry!” in VGB PowerTech issue March (3) 2014.
Unfortunately, due to the recent cost pressure, the repeated question arises if an own laboratory and hence power plant chemistry know-how is still needed. According to my opinion, this is strongly related. Laboratory coworkers belong to the operational staff of a power station and fulfil tasks far beyond pure analytics. The immediate advantage of power plant chemists belonging to the power station is their knowledge of the technological backgrounds and their direct contact to the sample and its “history”. Unusual measured results can be verified and, if necessary, hints for the optimization of operational adjustments can be given to the operational department. Experience of many years concerning analytical methods is available. Consequently, the deviation of measured results of e.g. waste water samples with high salt concentrations, resulting from well-known matrix effects or sensitivities, can be excluded. An own laboratory leads to the further advantage that the quality of external (e.g. official) analytics can be evaluated and that the needed know-how is located in the own company.
An additional important task of the power plant chemists is to keep an eye on the operation being in agreement with all chemical rules, which can be quite an effort. In most cases, deviations from standardized water qualities (according to the VGB-Standard VGB-S-010) only lead to damage after some time, e.g. due to corrosion or deposits on the turbine. Because of the delay between cause and effect, the chemists need to extendedly explain the acuteness to the operational staff.
Furthermore, the contribution of the chemists to checking the online analytics should not be underestimated. For instance, not every employee of a power station without knowledge of chemistry or measurement technology understands that a measured value of “0.0000” indicated on an online instrument generally means nothing positive. In some cases the employee is happy about the good conductivity in the water-steam cycle, the low sodium concentration or similar things. What should we then do without the power plant chemists who repeatedly point out that currently we operate in a “blind flight” mode?
However, the power plant chemists not only prevent damages by controlling the water chemistry. Numerous suggestions of optimization activities are made by chemists, especially concerning water and waste water treatment. This is only possible because of the close contact to the operational staff. The good network of the power plant chemists due to the VGB committees further leads to a perspective beyond the own power station.
Although all of this is true without restrictions, the cost pressure on the conventional thermal power stations remains enormously high, so that the role of the power plant chemist should be redefined, clever savings have to be made and an optimised use of know-how across locations has to be ensured.
The fully booked VGB conference “Chemistry in Power Plants 2015” indicated a large interest in the new challenges of the power plant chemistry. Current issues, which are partly described by articles in this journal, are e.g. the analytics and combat of
legionella in the cooling water, the reduction of mercury in the flue gas as well as possibilities of optimising online analytics and water treatment. A further big issue is the conservation of power plants, especially in view of decreasing operational hours. First it should be thought of the water-steam cycle but the auxiliary plants should not be forgotten either. The special challenge results of the situation that it often cannot be foreseen how long the standstill will last. VGB PowerTech will therefore soon edit a completely revised standard. Additionally, it is necessary in every case to generate a profound concept for the own power station, in collaboration with the chemists. The concept should pay attention to the specific onsite circumstances.
For these current issues as well as for continuing the operation of our power plants with a low failure rate, the power plant chemical know-how that has been created during the last decades, is essential. We put all our effort into its preservation and efficient application. The challenges never decrease, so the power plant chemistry stays an important part of the daily operation of our power plants!