The majority of interest in mercury control at coal-fired plants has been in North America, where emission standards for mercury and other pollutants have been set at such a challenging level that many plants face costly retrofits whilst others face closure. However, continued arguments over MATS (the Mercury and Air Toxics Standard) in Federal court only last month have pushed the compliance date for some plants back yet another year to 2017 instead of 2015. Despite this, many plants will move ahead with controls and others are already compliant with the new standards.
In the past the EU has been slower to move against mercury-specific controls as the technologies installed to comply with existing legislation (the old Large Combustion Plant Directive and new Industrial Emissions Directive, IED) for SOx and NOx also resulted in “co-benefit” mercury removal. Mercury emissions from the coal sector have been declining for decades as a result.
But as the UNEP (United Nations Environment Programme) Minamata Convention on mercury moves towards ratification, the EU is heading for more defined mercury control at coal-fired plants and this is adding momentum to the tightening of the guidelines on BAT (best available technology) as they apply under the IED.
The current draft of the BREF (BAT reference document) lists all the options for mercury control, from fuel blending and switching, to bolt-on flue gas treatments. But none is specifically required under the existing IED. In fact, the only reference to mercury within the IED is the requirement for annual monitoring. However, the current draft of the new BREF includes a list of potential emission limits for mercury which could be as low as 0.2 micrograms/m3 or up to 10 micrograms/m3 (for plants over 300 MW). The actual value has yet to be agreed and the applicability of the proposed limits has yet to be defined but it could mean that some plants will be required to install flue-gas polishing techniques for mercury in order to comply. This means there may be a new mercury control market opening up in Europe within the next few years.
With this in mind, Poland, the EU member state with probably the greatest dependence on coal, has started to make moves towards determining compliance options for this potential new mercury limit at its existing plants. Tauron is largest distributor and supplier of electricity in Poland. It is also the second largest electricity generator in Poland and the largest supplier of heat in Upper Silesia. The holding controls approximately 20% of Polish hard coal resources. The company is currently working with http://www.kic-innoenergy.com/ to use international and national funding to support R&D relevant to the energy sector. This research is being carried out in academic institutions such as the AGH University of Science and Technology. This approach is intended to foster better relations between academia and industry, something that is often lacking in the energy sector. The current mercury programme coordinated by KIC InnoEnergy facilitates the progression of pilot-scale projects at AGH University through to demonstration and full-scale installations at full-scale coal-fired plants in Poland, whilst establishing patents and other industrial advantages along the way. AGH is currently working on several mercury reduction projects, from coal cleaning through to control technologies such as sorbents and activated carbons. One of the most advanced projects is a sorbent injection system which is currently being trialled at the Lagisza power plant, a 460 MW circulating fluidised bed plant owned by Tauron. The international mercury meeting, organised by Janusz Golaz at AGH, included a site visit to the Lagisza plant to see the system in practice. Initial results from the trials seem very positive, although the project is still in start-up phase. Similar sorbent injection trials are under-way at the Belchatow Lignite Power Plant in Poland, although on a smaller (1:200 scale) demonstration system. Belchatow is a >5GW lignite plant, the largest in Europe, and therefore both a significant challenge and an excellent target in terms of mercury control.
The mercury meeting at AGH was an excellent mix of small scale laboratory studies and full scale demonstration projects, all highlighting the challenges faced by the coal sector when it comes to reducing mercury emissions in real terms. With the requirements for mercury control looming on the EU horizon, it is encouraging to see such a coal-dependent nation as Poland getting ahead of the game and moving towards control strategies on some of its largest plants. It is also encouraging to witness the full evolutionary journey of a project from a student laboratory through to a potential full-scale installation, something which should be encouraged, and more importantly – funded – significantly more in the international community.
The proceedings of the meeting are not currently available on-line but if this changes, a link will be provided.