The 13th ExPPERTS Europe conference explored power plant emission reduction technologies and strategies, as a result of the need to comply with new EU Large Combustion Plant (LCP) emission limits for SO2, NOx, PM, Hg, HCl and HF.
The new emission limits for LCP are the result of a review of the Best Available Techniques (BAT) Reference Document for Large Combustion Plants (LCP BREF) which was published on 17 August 2017 in the Official Journal of the European Union. The BAT-AEL (associated emission levels) are also summarised in the IEA CCC emission standards database. The conference enabled delegates from power plant utilities from several European countries, the cement industry, technology suppliers and representatives from various environmental bodies to meet and exchange ideas. The presentations covered regulatory aspects, and technology solutions and innovative processes for meeting the limits.
Martin Muhrberg from the German Energy and Water Industries (BDEW) highlighted the implementation of the Industrial Emissions Directive (IED) in Germany in relation to mercury emissions from large and medium combustion plants. Technologies trialled to reduce these emissions, such as activated carbon injection, and the lessons learned were presented. Power plants in the USA already have experience in controlling mercury emissions to meet US regulations with sorbent injection systems in commercial operation. Ian Hodgson (EC) described the state of play of legislation from the European Commission and gave an assessment of the expected impacts of the LCP BAT conclusions, including costs and benefits. He was not aware of any plant being closed as a result of the LCP BREF regulations. Tomasz Zukowski described some of the sorbents that his company, Cobot Norit, has developed that can cope with elevated SO3 concentrations in the flue gas, which can reduce the efficiency of mercury removal. The theme of mercury control was continued by Pavel Frolka of the ČEZ Group. Czech lignites generally have low chloride, high sulphur and mid to high mercury contents. He described how mixing some 2 wt% of hard coal with lignite in fluidised bed combustors (<300 MWth) enabled the mercury limit to be met. The ČEZ have selected and tested suitable precipitation agents for pulverised hard coal plants and lignite plants (≥300 MWth). Tailor-made SCR catalyst solutions for controlling NOx emissions were then described by Robert Zmude from SBB Energy using case studies in Poland. Catalysts have to be replaced after a few years but the cost is small in relation to the cost of construction and installation of a SCR system.
A change of topic occurred in the presentation I gave on emissions to water instead of to the air. Significant areas on nearly every continent are suffering from water stress, and this is likely to increase in the future. Power plants in India, for example, have had to temporarily shut down for days, or even months, due to water shortages. Consequently, power plants will need to look for alternative non‑fresh water sources, retrofit water saving technologies and/or treat and reuse the generated waste water. I described discharge limits for FGD waste water and technologies for treating it, based on information from my recent reports, available here.
The presentations after an excellent lunch began with Guofeng Zhou from Umicore looking at considerations for SCR catalysts when using biomass in power generation. Cofiring up to 20% of biomass with coal generally does not lead to deactivation of the catalyst by the phosphorus and potassium in the biomass, and injection of coal fly ash can help prevent deactivation in biomass (straw) combustion. Marek Michalski from Lafarge Cement discussed controlling SO2 and NOx emissions from cement plants in Poland. SO2 is removed by wet scrubbers or dry lime addition. The Polish cement industry is one of the biggest users of municipal and industrial waste where it is used to replace fossil fuels and consequently, to reduce CO2 emissions. Hanif Suchwani from Fuel Tech discussed controlling NOx and SO2 emission limits in power plants, including the company’s multi-nozzle system for injecting urea into the boiler to improve NOx removal. Flue gas conditioning can improve the performance of existing ESP for controlling PM. Rehabilitation of the Tušimice II and Prunéřov II CHP plants to improve efficiency and reduce emissions was described by Jan Šimunek, Škoda Praha a.s. The difficulty of getting permits was illustrated where It took nearly 5 years for Prunéřov II to obtain the relevant permits due to actions by environmental groups and others. The first day ended with Krsysztof Kepa, PGE, discussing how Poland’s energy sector could be facing a paradigm shift with a new energy policy on the cards. The effects of two possible scenarios were outlined with the audience encouraged to add their views.
The second day began with two roundtables – the first one I attended discussed the collaboration between applied science and business science and how this could productively contribute to industry. The chairman, Mariusz Podles, began with an example of a successful collaboration between his company, PGNiG TERMIKA, and Warsaw University on SCR. The round table then led onto a discussion on how to interpret the BREF concerning FGD waste water. Interpretation is up to each country, and so power plants may be treated differently in different countries.
The second roundtable, chaired by Tarja Korhonen, Valmet, discussed solutions for emission control. The problem of corrosion due to the use of bromides for mercury control is now understood and can be controlled. It is generally best to reduce NOx in the boiler as much as possible to reduce the load on the downstream SCR/SNCR. This could save on the cost of replacing SCR catalysts. The question was raised on what the cement industry will do when coal power plants close and fly ash is not available. More international trading of fly ash could occur.
Then it was back to presentations with Roger Brandwood, Uniper Energy, discussing how policies and regulations could affect the future of coal power plants and how they can adapt. Some unintended consequences of policy changes were touched on. Technologies for meeting the LCP BREF limits for HCl, HF and mercury that come into force in 2021 were outlined by Tarja Korhonen, Valmet, for coal and biomass plants. These include dry, semi-dry and wet scrubbing methods for HCl, and how to deal with the wastes, such as the chloride containing waste water. Utilising the waste contributes to the circular economy. A change in topic occurred with an interesting talk from Paul McCann, Uniper Energy, who described some of the corrosion problems that can occur in the water-steam cycle if a coal power plant is put on standby, and what protection measures are available. Carmen Schiel, Karlsruhe Institute of Technology, introduced the ERICCA_LCP (Emission Reduction and Investment Cost Calculation) software tool she helped to develop for power plant operators to assess the techno-economic impacts of SO2, NOx and PM control techniques for a specific power plant.
The conference ended with Rémi Bussac, EDF, discussing Coal: What else? This mainly discussed the role of biomass, and showed the difference in the emission limits given in the LCP BREF and the BREF on waste incineration. The combustion of biomass in power plants where it is not the main fuel is covered by the LCP BREF. The impact of the CO2 Emissions Performance Standard for Capacity Mechanisms (<550 gCO2/kWh) under discussion in the Clean Energy Package and how co-firing biomass could help meet the target was indicated.
There were many interesting presentations, but I was left with the thought that although the emission limits in the LCP BREF are strict, they could be even stricter when the next BREF update is published.
The 13th ExPPERTS Europe conference took place in Wroclaw, Poland 26 – 27 September 2018.