The influence of multiple process factors affecting the oil shale particles size distribution and the degree of fragmentation/pulverization was studied in fixed-bed during thermal effect.The results show that with the temperature increasing from 120℃ to 900℃

the fraction of retention particles (25-13 mm) is decreased from 96.54% to 82.69%.The fragmentation particles group (13-1 mm) are increased from 2.01% to 10.63%(13-6 mm grain size increased the highest rate);The pulverization particles group (less than 1 mm) are increased from 1.45% to 6.68%(the fractions of particles less than 0.075mm are significantly changed).The degree of fragmentation and pulverization are increased with particles size and holding time as well.Impact of multi-factor on fragmentation is revealed using gray relational analysis method as follows:temperature > size > time

and the impact on pulverization is:temperature > time > size.Through the analysis of TGA

XRF

XRD

SEM-EDS

the internal incentives affecting fragmentation/pulverization are revealed:vapor-volatile arising

calcite decomposition behavior

indirect reinforcement with time

and internal air resistance/particle material resistance.The descriptive model of oil shale fragmentation-pulverization in fixed-bed during thermal effect is built based on these factors.