The output and efficiency of a coal-fired power station unit fitted with CO2 capture equipment will be significantly lower than that of a similar plant without capture because some of the energy produced by burning the fuel will be needed to operate the added systems. Incorporating an aqueous amine-based CO2 scrubbing system in a simple arrangement could decrease the efficiency by as much as 30% of value. However, work at various research institutes and universities shows that the decrease in performance could be reduced by improved heat integration and other techniques. The webinar reviews these studies.
Coal contracts can be typically split into two broad categories, spot contracts (single shipments) and term contracts (multiple shipments). Term contracts can span any period, but in China in 2014, the National Development and Reform Commission announced a desire for coal buyers to negotiate long-term contracts with suppliers. Security of supply of fuel and limiting exposure to shorter-term volatility in prices and fuel supplies are clearly a strategic aim of some Asian economies. Such approaches to coal procurement is used across the world to varying degrees depending on the particular circumstances of the power generators and the markets in which they operate. This webinar provides an overview of a recent publication by the IEA CCC regarding coal procurement and contractual needs, and describes some of the aspects associated with the long-term nature of some coal contracts. It provides an introduction to some of the fundamentals of coal contracts and buying to those unfamiliar with fuel procurement, as well as a review of some regions which have been active in long term coal procurement in recent years.
Global energy demand is rising primarily as a result of population and economic growth in the emerging economies. Meeting this growing demand places increasing stress on limited fresh water resources as electricity production uses large amounts of water. This has repercussions for other water consumers in the agricultural, industrial and domestic sectors. Climate change could exacerbate the situation. This webinar examines the availability of fresh water for power generation, in particular for coal-fired power plants. It shows where the water stressed areas are in the world today and the demand for power. Global water and energy demand are discussed, and the water requirements of different power generation technologies. Some technologies that use less water, for example, dry-cooled power plants, operate at a lower efficiency. Finally, water availability and management in China and the USA, with reference to their energy production and policies are compared.
Most pulverised coal combustion (PCC) plants employ single-reheat cycles. However, double-reheat cycles can significantly improve the electrical efficiency of PCC plants. Surprisingly, no double-reheat units have been commissioned since the 1990s. However, with rising primary energy costs, more stringent emission limits and advances in thermal power engineering, double-reheat cycles are being considered to minimise the cost of electricity, reduce emissions and prolong valuable coal supplies, especially in China. This webinar reviews, analyses and assesses the application and development prospects of coal-fired double-reheat units.
Recent developments in process waste recycling and biomass utilisation have driven the use of these so-called ‘low value fuels’ for energy generation on a stand-alone basis, and in combination with coal. One particular technology stands out as being particularly well suited to utilising these low value fuels, circulating fluidised bed combustion (CFBC). The upcoming webinar sets out examples of the range of low value fuels, their reserves and properties, with particular emphasis on coal-derived materials, the issues for CFB plant in utilising these fuels and selected examples of manufacturer and operator experience with purpose built, or modified CFB plant.
Coal power plant control systems have progressively evolved to meet the growing demand for efficient and flexible power generation whilst maintaining low emissions. In particular, optimisation of the combustion process has required increased use of online monitoring technologies and the replacement of standard control loops with more advanced algorithms
capable of handling multivariable systems. Improved stoichiometric control can be achieved with
coal and air flow sensors or imaging and spectral analysis of the flame itself, whilst in-situ laser absorption spectroscopy provides a means of mapping CO and O2 distribution in hot regions of the furnace. Modern plant control systems are able to draw on a range of computational
techniques to determine the appropriate control response, including artificial intelligence which
mimics the actions of expert operators and complex empirical models built from operational data.
New sensor technologies are also being researched to further improve control and to withstand the high temperature and corrosive environments of advanced coal plant and gasifiers. Increased use of optical technologies is of particular interest, with sensors based on optical fibres able to perform low noise, highly sensitive, and distributed measurements at high temperatures.
Microelectronic fabrication techniques and newly developed high temperature materials are also being combined to develop miniaturised devices which provide a robust and low cost solution for in-situ monitoring of gases and other parameters. These new sensors can be integrated with wireless communication technology and self-powering systems to facilitate the deployment of distributed sensor networks and monitoring of inaccessible locations. Using principles of self-organisation to optimise their output, such networks may play a growing role in future control systems.
Microalgal removal of CO2 from flue gas
Various methods have been developed to remove CO2 from the flue gas of coal-fired power plants. Biological post-combustion capture is one of these. Microalgae may be used for bio-fixation of CO2 because of their capacity for photosynthesis and rapid growth. The ability of microalgae to withstand the high concentrations of CO2 in flue gas, as well as the potentially toxic accompanying SOx and NOx has been researched. Microalgal strains that are particularly suitable for this application have been isolated. Most of the research on algal bio-fixation has been concerned with carbon fixation strategies, photobioreactor designs, conversion technology from microalgal biomass to bioenergy, and economic evaluations of microalgal energy. This webinar considers current progress in algal technology and product utilisation, together with an analysis of the advantages and challenges of the technologies. It opens with a brief introduction to the theory of algal bio-fixation and factors that influence its efficiency especially in terms of flue gas characteristics, and then discusses culturing, processing technologies and the applications of bio-fixation by-products. Current algae-based CO2 capture demonstration projects at coal-fired power stations around the world are described.
Competition between coal and natural gas for power generation has been observed to occur in North America and Europe in recent years, where the costs of the two fuels have played a key role in determining the relative competitiveness. It is perceived that such a competition could also happen in Asian countries. More importantly, as these countries are expanding their generation capacity to meet growing electricity demand, a key question is raised of whether coal or gas power plants should be built with priority. This webinar is based on a recent report published by IEA CCC, where the authors investigate nine Asian countries to seek to understand the mechanisms that drive the competition between coal and gas for power generation.