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

Effects of chirality on the intracellular localization of binuclear ruthenium(II) polypyridyl complexes

Interest in binuclear ruthenium(II) polypyridyl complexes as luminescent cellular imaging agents and for biomedical applications is increasing rapidly. We have investigated the cellular localization, uptake, and biomolecular interactions of the pure enantiomers of two structural isomers of [μ-bipb(phen)4Ru2]4+ (bipb is bis(imidazo[4,5-f]-1,10-phenanthrolin-2-yl)benzene and phen is 1,10-phenanthroline) using confocal laser scanning microscopy, emission spectroscopy, and linear dichroism. Both complexes display distinct enantiomeric differences in the staining pattern of fixed cells, which are concluded to arise from chiral discrimination in the binding to intracellular components. Uptake of complexes in live cells is efficient and nontoxic at 5 μM, and occurs through an energy-dependent mechanism. No differences in uptake are observed between the structural isomers or the enantiomers, suggesting that the interactions triggering uptake are rather insensitive to structural variations. Altogether, these findings show that the complexes investigated are promising for future applications as cellular imaging probes. In addition, linear dichroism shows that the complexes exhibit DNA-condensing properties, making them interesting as potential gene delivery vectors

3 rd i-CIPEC

Abstract: Co-combustion of sewage sludge with coal or wood as base fuels may cause high emissions of sulphur dioxide and hydrogen chlorine to the atmosphere. The conventional technique for sulphur capture in fluidised bed combustion using coal, lime addition, works well under co-combustion conditions with coal as base fuel but not with wood. The concentration of SO2 certainly plays a role, but phosphorous, originating from the sewage sludge, forms calcium phosphate that may interfere with the sulphur capture reactions normally taking place when lime is added to the bed. Lime addition to the fluidized bed during combustion of pulp&paper sludge, not containing phosphorous and with similar sulphur levels as for the sewage sludge, gives a normal sulphur capture. Adding hydrated lime to a bag filter is an alternative to lime addition to the bed that can be used when fuels with high content of phosphorous are co-combusted with wood. Hydrated lime also captures chlorine in the bag filte

Chalmers Publication Library Gas Phase Alkali Chlorides and Deposits during Co-Combustion of Coal and Biomass Gas Phase Alkali Chlorides and Deposits during Co- Combustion of Coal and Biomass

Abstract Straw pellets have been co-fired with a bituminous coal with a high chlorine content. The tests were carried out in a 12 MW circulating fluidized bed (CFB) boiler located at Chalmers University of Technology in Sweden. The tests focused on variation of the ratio of straw to coal in combination with different feeding rates of limestone to the bed. Three test series were carried out: Lime -the fuel was a constant mixture of coal and straw pellets, with an increasing lime supply; Coal -the fuel was coal only, with an increasing lime supply. Alkalithe fuel was coal and straw pellets and constant lime supply. The fraction of straw pellets (alkali) was increased. An In-situ Alkali Chloride Monitor (IACM) was used during the tests to measure the on-line concentration of alkali chlorides and SO 2 before the convection section of the boiler. Deposit measurements were also carried out and the deposits were analysed by means of SEM-EDX. It was found that an increased fraction of straw pellets in the fuel mix results in increased level of alkali chlorides in the gas phase as well as in collected deposits. Introduction Co-combustion of biomass with coal or other primary fuels has many potential advantages: the effective emission of CO 2 is reduced by replacing a certain amount of coal with biomass, and efficient utilisation of the energy in biomass by converting it to electricity in a coal power station. There are also potential risks: some biofuels may lead to deposit formation on heat exchanger surfaces in the combustor or to bed agglomeration in a fluidised bed. Fluidised bed combustion is probably the most advantageous method available for co-combustion due to its fuel flexibility and the possibility to influence the processes of formation and destruction of emissions. There are several important factors to investigate when co-firing coal and biomass. This project focuses on the possibility of co-firing a troublesome fuel (with respect to alkali related problems) such as straw with coal. Gas phase alkali chlorides was measured by means of an In-situ Alkali Chloride Monitor (IACM) and SEM-EDX was used for analysis of collected deposit. IACM was also used as a tool for on-line judgements of the limits of co-firing in order to avoid deposit problems. The results from SEM-EDX analysis were used to support the results from IACM. The results were also discussed with respect to mechanisms that could explain the positiv