The Clean Coal Centre’s biennial flagship event, the International Conference on Clean Coal Technologies (CCT2015), was held last week in Krakow with the help of our local hosts, the Central Mining Institute of Poland. The event brought together some major players from the energy industry, national research institutes, and universities from coal regions around the world, with almost 200 participants attending from over 30 countries. Being involved in the organisation meant that I wasn’t able to get to as many of the 120 or so presentations as I’d have liked, but I’ll try to pick out some of the highlights I came across over a busy and informative three days.
A key theme of this year’s conference was how coal plants can meet the challenge of operating flexibly enough to provide effective backup to intermittent renewables. This was highlighted in the first day’s keynote from Oliver Then of VGB Powertech, which looked at the growing economic and technical pressure on coal plant already occurring in Germany, where dispatch priority for the large proportion of renewables on the grid has forced coal plant to operate for significantly reduced hours at lower energy prices. In future, these conditions may force a shift away from large, high efficiency plants, to smaller plants designed for maximum flexibility. A great series of presentations from Mitsubishi Hitachi Power Systems addressed the technical solutions which have been developed to improve plant flexibility, including reducing material thicknesses to mitigate the effect of thermal stresses, lowering minimum load by using more mills and new burner designs, and achieving rapid, cheaper startups with electrical burner ignition. As a solution for large scale energy storage – still the biggest problem facing renewable-rich grids – conversion of excess power to methanol transport fuel was proposed as a highly competitive option, using captured CO2 as the carbon source.
Another effective means of optimising plant efficiency, flexibility, and availability, upgrades to control systems were also well-represented, including online coal and air flow sensors from Promecon and neural network-based controls from NeuCo which can both help keep boilers tuned to the operational sweet spot for efficiency and NOx emissions. Already successful in the US, NeuCo’s recent collaboration with Alstom may lead to much wider adoption of this kind of approach elsewhere. The importance of these technologies to future coal plant has been fully recognised by the US Department of Energy, whose extensive sensors and controls research programme was detailed by NETL’s Robert Romanosky. With research aims including microelectronic sensors which can be embedded into plant components through additive manufacturing, and new control paradigms based on intelligent, wireless sensor networks, it is clear that there is considerable scope for integrating coal plant with cutting edge technologies in this field.
Minimising emissions of conventional air pollutants such as SOx, NOx and particulates, remains a priority for the coal industry worldwide, with tighter emissions limits on the horizon and mercury now also facing regulation. This is nowhere more the case than in China, where serious air quality problems have spurred the government and coal industry into action over the last five years. A presentation from utility Shenhua Guohua Power detailed their ‘near zero emissions’ technology which has managed to meet not only China’s stringent emissions targets for coal plants but also those for gas plants, essentially through optimising existing abatement technologies. Even with the additional capital expense, these cleaner coal plants still represent a much more economic alternative to gas turbines due to their much lower fuel costs. I also managed to attend the session dedicated to NOx controls, which covered a diverse range of approaches for optimising SNCR, including ‘smart’ ammonia injection targeted using real-time CFD modelling of boiler temperatures. These kind of developments are increasingly allowing SNCR to compete with SCR installation even for larger plants and low emissions targets.
Unsurprisingly, carbon capture in all its forms was an ever-present theme throughout the conference, although the dominance of relatively small-scale research bore testament to the continued struggles faced by capture demonstrations in Europe especially. A keynote from Juho Lipponen of the IEA provided insight into the factors which are making certain CCS demonstrations more viable, including certainty of the fuel source, revenue for the CO2, governmental support, and the strategic advantage of claiming a technical ‘first’. As many of these success stories are in the USA, where the value of CO2 for enhanced oil recovery in the southern states is helping a handful of large CCS demos get going, an update from NETL’s Tom Sarkus gave more encouraging news for CCS proponents. Besides the long-awaited Kemper IGCC project, due to start operations next year, two other precombustion capture plants are planned, and a 240 MW postcombustion slipstream on the Petra Nova plant in Texas has already broken ground. Results from smaller scale local projects included Polish utility Tauron’s ‘split flow’ amine pilot, which improves the energetic integration of the stripper and adsorber columns, and a relatively unique solid sorbent pilot based on pressure swing adsorption.
This PSA capture pilot was also one of the highlights of Thursday’s excursion to Tauron’s Lagisza power plant, where it has been successfully operating for around a year on a small flue gas slipstream. The plant itself is already renowned for its 460 MW circulating fluidised bed boiler, which was the world’s first ever supercritical CFB and remains the largest of its kind outside China. Having extensively researched this plant myself, this was a rare opportunity to have such a close up look at the unit as well as the capture pilot. The visit also followed nicely from Wednesday’s talk by Amec Foster Wheeler, designers of the CFB unit, who provided an update of their ongoing projects in this field including the four 550 MW CFB units which will start up in South Korea next year.
Fortunately, the conference was not all about work, as on Tuesday night delegates descended into the world-famous Wieliczka Salt Mine for a dinner in the unusual and spectacular surroundings of a cavern carved from rock salt. The dinner was preceded by a tour of some of the fascinating network of chambers and their elaborately carved decorations dating from throughout the mine’s long history.
I have only been able to touch on a fraction of CCT2015 here, missing the major themes of gasification, biomass cofiring, and underground coal gasification, amongst others. However, all presentations will be made available to delegates from the conference website in the next couple of weeks, and will become open access after six months. I’d like to thank everyone who presented and attended for contributing to such a successful and truly international event, and I hope we will see everyone again for the next edition in Sardinia, May 2017.