Compatibility Evaluation between Direct Coal Liquefaction Residue and Bitumen

The compatibility between direct coal liquefaction residue (DCLR) and five kinds of pure bitumen (Shell-90, SK-90, ZSY-70, DM-70 and KLMY-50) was evaluated in this study. The rheological characteristics, glass transition temperatures (Tg), solubility parameters (SP) and SARA (saturates, aromatics, resins, and asphaltenes) fractions of DCLR, five kinds of pure bitumen and their blends (named as DCLR modified bitumen) were measured using the dynamic shear rheometer (DSR), differential scanning calorimetry (DSC), viscosity, and SARA tests, respectively. And the compatibility between DCLR and pure bitumen was characterized with three approaches, viz. the Cole-Cole plot, Tg, and the solubility parameter difference (SPD) method. Since each method has its own working mechanism, the compatibility ranking for the DCLR and five kinds of pure bitumen is slightly different according to the three approaches. However, the difference is pretty close and sometimes can be ignored. The general compatibility ranking decreases in the following order: Shell-90≈SK-90>DM-70≈ZSY-70>KLMY-50, which is affected by the asphaltenes content and the colloid index (Ic) value in the pure bitumen. Pure bitumen with lower asphaltenes content and colloid index (Ic) value has better compatibility with DCLR.