Co-firing of biomass and other wastes in fluidised bed systems

A project on co-firing in large-scale power plants burning coal is currently funded by the European Commission. It is called COPOWER. The project involves 10 organisations from 6 countries. The project involves combustion studies over the full spectrum of equipment size, ranging from small laboratory-scale reactors and pilot plants, to investigate fundamentals and operating parameters, to proving trials on a commercial power plant in Duisburg. The power plant uses a circulating fluidized bed boiler. The results to be obtained are to be compared as function of scale-up. There are two different coals, 3 types of biomass and 2 kinds of waste materials are to be used for blending with coal for co-firing tests. The baseline values are obtained during a campaign of one month at the power station and the results are used for comparison with those to be obtained in other units of various sizes. Future tests will be implemented with the objective to achieve improvement on baseline values. The fuels to be used are already characterized. There are ongoing studies to determine reactivities of fuels and chars produced from the fuels. Reactivities are determined not only for individual fuels but also for blends to be used. Presently pilot-scale combustion tests are also undertaken to study the effect of blending coal with different types of biomass and waste materials. The potential for synergy to improve combustion is investigated. Early results will be reported in the Conference. Simultaneously, studies to verify the availability of biomass and waste materials in Portugal, Turkey and Italy have been undertaken. Techno-economic barriers for the future use of biomass and other waste materials are identified. The potential of using these materials in coal fired power stations has been assessed. The conclusions will also be reported

Integrating calcium looping CO<inf>2</inf> capture with the manufacture of cement

his paper investigates the trace element content of calcium oxide sorbent after repeated cycles of calcination and carbonation in the presence of fuel combustion during the calcination step. The trace element content of the sorbent was measured using ICP-OES after a wet acid digestion procedure. The weight % of alite, the cement phase responsible for short-term strength of the cement, has been measured using XRD for cement prepared in the laboratory from single cycled and repeatedly cycled sorbent. The results indicate that repeated cycling does lead to an increase in the concentration of some trace elements entering the sorbent from the fuel. However the increase in these concentrations was not enough to impact upon the weight % of alite in the resulting clinkers produced from the sorbent