Energy & Fuels, Vol.29, No.10, 6734-6746, 2015
Simultaneous Online Determination of S, Cl, K, Na, Zn, and Pb Release from a Single Particle during Biomass Combustion. Part 1: Experimental Setup-Implementation and Evaluation
The interest in experimental data regarding thermal fuel decomposition as well as the release behavior of ashforming elements of biomass fuels for modeling and simulation purposes is continuously increasing. On the basis of combustion experiments with lab-scale reactors and single-particle reactors, integral release data regarding ash-forming vapors can be obtained, whereby the release is calculated on the basis of analysis data of the fuel and the ash residues. At the moment, almost no time-resolved release data of ash-forming elements from single particles exist. Therefore, a single-particle reactor was designed, which has been coupled to an inductively coupled plasma mass spectrometer (ICP-MS). This reactor can be used for targeted experiments in a temperature range of 250-1050 degrees C under inert, reducing, and oxidizing conditions. With this reactor, it is possible to simultaneously determine the surface and center temperatures of a biomass particle, weight loss of the particle, and flue gas composition. The reactor has been coupled to an ICP-MS through a gas stream that is sufficiently diluted with Ar. First performance tests with pure salts (KCl, NaCl, (NH4)(2)SO4, ZnCl2, and PbCl2) proved that relevant volatile ash-forming elements can be detected with the ICP-MS. For a further validation of the received signals, combustion tests with Miscanthus pellets have been carried out, whereby the controlled interruption of the experiments has also been investigated. These tests prove that with this system the simultaneous time-resolved determination of S, Cl, K, Na, Zn, and Pb is possible whereby the Cl signal can only be used with restrictions. On the basis of the determined release of ash-forming elements for the entire combustion experiment, a quantification/calibration of the measured intensities has been carried out. The data gained from these tests will provide deeper insights into release processes as well as form a relevant basis for release model development.