Influence of Compatibilization Methods on the Compatibility Between Asphalt and DCLR Components with Molecular Dynamics (MD) Method

This study aims to investigate the effect of compatibilization methods on the compatibility between asphalt and direct coal liquefaction residue (DCLR) components to identify the key components in DCLR and asphalt that affect their compatibility. In this article, three types of compatibilizers, including benzyl alcohol (BA), dioctyl phthalate (DOP), and BA/DOP, were selected and acted on asphalt's components and DCLR's components, respectively. The molecular models of asphalt components, asphalt components with compatibilizers, DCLR components, and DCLR components with compatibilizers were established. The compatibility between DCLR and asphalt's four components, as well as between asphalt and DCLR's three components, were evaluated by solubility parameter difference (SPD) and interaction energy (IE). The compatibility between DCLR and asphalt was analyzed by Segregation test and Scanning Electron Microscope. Results indicate that the SPD and IE values between DCLR and asphalt components declined after adding compatibilizers, which implies that the repulsion decreased and the attraction increased between asphalt components and DCLR and the compatibility between asphalt components and DCLR improved. The IE values between DCLR components and asphalt increased after adding compatibilizers, which indicates that the compatibility was reduced between DCLR components and asphalt. The SPD values between DCLR components and asphalt increased after adding the BA/DOP. The SPD values between pre-asphaltene and asphalt decreased after adding the BA and DOP. The SPD value between asphaltene in DCLR and asphalt increased after adding the BA and decreased after adding the DOP. Moreover, the storage stability and homogeneity of DCLR-modified asphalt improved after adding compatibilizers, indicating that the compatibilizers enhanced compatibility between DCLR and asphalt. Finally, comparing the results of the tests, it could be found that compatibilizers preferentially acted on the asphalt components and mainly affected the aromatics in asphalt, thereby improving the compatibility between asphalt and DCLR. The effect of BA/DOP on improving the compatibility between asphalt and DCLR was better than that of BA and DOP.