1990 Volume 39 Issue 7 Pages 481-485
One important problem stemming from coal oil mixture (COM) utilization is the generation of cohesion products on the walls on the equipment of the COM flowing process (dynamic instability). The stability of coal slurry fuel (CSF) was examind in this study using, with suitable additives, the “Cylinder soaking test” and “Pipe passing test”, developed in our previous work.
COM with additive-A (COM-A) was conducted and considerably more cohesion was detected than when using additive B. This clearly demonstrates the stability of COM. These tests can thus be used to rapidly assess the stability of COM. Even when using additive B, greater cohesion was detected under condition of high shear stress and temperature.
Using a coal water mixture (CWM) with various additives, “Cylinder soaking test” and “Pipe passing test” were carried out. Coal mean particle size in CWM was about half that inraw coal, with ash content being slightly higher than in raw coal. Coals of fine particle size and high ash content may thus possibly cohere predominantly, this being quite consistent with the findings of studies on COM.
The rapid estimation of CSF stability as shown here was found applicable to COM and should prove quite useful for the preparation of high performance additives of COM and CWM in the future.