Study On Compatibility Between Direct Coal Liquefaction Residue And Bitumen

Direct Coal Liquefaction Residue(DCLR),as a by-product of direct liquefaction production technology,can be added to bitumen as a modifier in road engineering.In this paper,the compatibility between DCLR bitumen is evaluated at multiscale.Firstly,five representative Bitumens(Shell-90,SK-90,DM-70,ZSY-70,KLMY-50)were selected according to asphaltene content and the Ic value.The characteristics of materials were analyzed by SARA,elemental analysis,functional group analysis and molecular weight distribution.It was found that compared with five bitumens,the saturated and aromatic(oil)content and molecular weight of DCLR were lower,the bitumenene content was much higher than bitumen,and the functional groups are mainly alkanes.There are also certain amounts of olefins and carboxylic acids.Secondly,five blends of bitumen and DCLR were prepared.The compatibility between DCLR and bitumen was evaluated by segregation softening point method,glass transition temperature method(Tg),solubility parameter difference method and Cole-Cole plot method.It was found that the compatibility of Shell-90 and SK-90 with DCLR was better than that of KLMY-50 with DCLR.Therefore,the order of compatibility between DCLR and five Bitumens is Shell-90≈SK-90 > DM-70≈ZSY-70 > KLMY-50.The Cole-Cole plot based on rheological method is more suitable for evaluating the compatibility between DCLR and bitumen.Thirdly,three kinds of Bitumens(Shell-90,ZSY-70 and KLMY-50)with different DCLR content(0%,4%,8%,12%,16%)were selected to prepare blends.The influence of DCLR content on the compatibility of DCLR with bitumen was analyzed by Cole-Cole plot.Based on Cole-Cole plot,it is recommended that DCLR content should not exceed 12% in DCLR modified Shell-90 bitumen,8% DCLR modified ZSY-70 bitumen,and the compatibility between DCLR and KLMY-50 is poor.DCLR is not suitable for the modification of KLMY-50.Finally,the mechanism of compatibility between DCLR and bitumen was studied by IR,SARA,GPC and AFM.It is found that when the asphaltene content and Ic value in bitumen are low,its compatibility with DCLR is the best.