According to Niu [2], different ashing rates and different ashing
temperatures lead to different ash compositions, which affect the
ash fusion characteristics (AFC). Therefore, it is essential to establish
an appropriate standard for ash preparation for determining
the biomass AFC. The fusion characteristic of the biomass ash is
affected by the high-temperature behaviour of the mixtures, which
are often eutectics, and is not a simple function of the major element
content in the ash. Changes in the proportions of certain metals
can therefore have significant effects on the fusion
characteristics. At temperatures above 815 C, potassium and chlorine
begin to be released to the gas phase, reducing the relative
content of K2O in the resulting ash.
2. Experimental methods
Twenty solid biomass fuels were selected for this study. These
are typical materials used in large scale power plant, many of them
being sourced from power plant operators. The selection includes
forestry biomass, energy crops, agricultural residues and a torrefied
biomass thus providing a range of differing ash compositions.
The reference names adopted for these sample fuels are
given in Table 1.
The samples of ash for analysis were prepared from portions of
the raw materials following the British/European Standards [7,8].
Samples with