ISBN: 9282832570 9789282832578

Category: Unavailable

Page count: 132

As a part of the EU-JOULE project JOR3-CT95-0001 and in cooperation with the IEA Bioenergy Agreement, TASK XIII, Activity 6 "Integrated Bioenergy Systems", 16 laboratories participated in this Round Robin on biomass fuel and ash analysis. The aim of the Round Robin was to provide a basis for establishing international standards for the correct and complete detection of trace elements in biomass fuels and for the reliable detection of elements in the different ash fractions produced in biomass combustion/gasification plants. The investigation was to cover all relevant analytical steps, sample homogenization, sample digestion and analysis itself. Four fuel samples (milled and unmilled samples of straw and bark), four ash samples (bark bottom ash, bark and straw fly ash, condensation sludge) and two digest solutions (from the milled straw and from the condensation sludge) were investigated in the Round Robin. The fuel samples were analysed for their concentrations of water, Ca, P, K, S, CI, Zn, Pb, Cd, ell and the total ash content. The ashes were analysed for their concentrations of water, Ca, P, K, S, Cl, Zn, Pb, Cd, Cu, C combustible and C C02 and the digest solutions for the parameters Ca, P, K, S, Zn, Pb, Cd and Cu. All participating laboratories were free to choose the respective analytical methods, only recommendations and information concerning available experience and possible problems that might occur in certain cases were supplied. The results from the participating laboratories were statistically evaluated for intra- and interlaboratory outlier values with a distribution-free method called Huber's method. The reason for using the Huber's outlier test and not the common ISO 5725 method was that in this Round Robin the participating laboratories were using the procedures and methods they have experience with and that they normally use for biomass fuel and ash analyses. Consequently, the results were not obtained using the same protocol for a certain analysis and therefore a robust method based on the median value instead of the average (mean) value was required for the statistical evaluation. The results of all participating laboratories were treated equally in this evaluation; the resulting medians were used as guiding values for the probably true values. Moreover, homogeneity tests for several biomass samples used in the Round Robin were performed separately. Subsequently, an analytical evaluation was performed by comparing the different methods and the equipment used for sample homogenization, digestion and analysis with the results achieved. The results of the statistical as well as the analytical evaluation are shown in diagrams and tables for all samples and all elements investigated. In addition the most important results are discussed separately for biomass fuels and ashes, distinguishing in both cases between the homogenization, the digestion and the analysis step and between specific problems that occurred for certain elements. Finally, an analysis meeting was held to discuss the results of the Round Robin for both biomass fuel and ash samples element by element. The aim of this meeting was to ensure that the accuracy and comparability of analytical results will fulfil the technological requirements for the calculation of material balances for ash-forming elements in biomass combustion/gasification plants