The resolution ratio of conventional slagging judgment indices is comparatively low

the result being often inconsistent with the reality. Based on the fuzzy mathematic theory

a collection of judgment factors was established by using five indices with higher resolution ratio

namely solftening temperature t 2

silicon ratio G

silicon aluminum ratio SiO 2/Al 2O 3

alkali/acid ratio B/A

and comprehensive index R

then a comprehensive judgment of slagging tendency for four samples taken from different points of a coal-water slurry fired boiler at Liaohe Oil Field was carried out. In order to ensure the concrete effectiveness of the established model

the said model and a former model of "four factors" are used respectively to judge eleven coal samples with known slagging degrees taken from Longkou Power Plant etc.

and a comparison of the results with real slagging status has been made

so as to enhance the reliability of judgment results.