Effect Of Additives On The Stability Of Coal-Oil Slurry And The Reaction Of Coal/Heavy Oil Hydrogenation Co-Refining

Coal-oil slurry is a raw material for coal/heavy oil hydro-co-processing.As a solid-liquid dispersion system,the decrease of its stability can lead to a large number of solid particles depositing and blocking pipelines,which will affect the storage,transportation and reaction of coal-oil slurry.Improving the stability of coal-oil slurry is one of the key technologies of coal/heavy oil hydro-co-processing.Therefore,in this paper,the solid content was used as the stability evaluation index,and the conversion rate of dry ash-free coal and the yield of light oil were used as the evaluation indexes of reaction performance,and the effects of additives types and addition amounts on the stability and reaction performance of different types of coal slurry were investigated.The characteristics of solid sediment of coal-oil slurry and the solid residue after reaction were characterized by SEM,FT-IR,XRD and particle size analysis.The formulation of additives which can improve the stability and reactivity of coal-oil slurry was optimized,and the mechanism of additives for stabilizing coal-oil slurry was preliminarily discussed.The results showed that the ability of surfactant additives to stabilize coal-oil slurry was nonionic surfactant>no additive>anionic surfactant>cationic surfactant.Anionic and cationic surfactants can reduce the stability of coal-oil slurry.Non-ionic surfactants PVP and tratton X-100 can enhance the stability of coal-oil slurry to a certain extent,but the effect was not very significant.Adding different types of polymers,polymer A can significantly improve the stability of coal-oil slurry.With appropriate addition amount,coal particles can be evenly dispersed in coal-oil slurry,and there was no coal powder sedimentation and agglomeration at the bottom of the slurry.Polymer A with different molecular weight has different stabilizing ability for coal-oil slurry.The higher molecular weight,the more remarkable stabilizing effect.It is also suitable for coal-oil slurry with different concentration and coal type.In the slurry-bed hydrotreating system of coal-oil slurry,the conversion and light oil yield of dry-based ashless coal were improved after adding surfactant SDBS,the solid residue had lower yield,smaller particle size,looser structure,higher aromaticity and branching degree,and increased the conversion of coal.After adding polymer A,the conversion of dry ash-free coal and the yield of light oil were slightly higher than those without additives.The properties of solid residue were between those without additives and SDBS,and the particle size was more uniform.Polymer A can significantly improve the stability of slurry while maintaining the reaction performance of coal-oil slurry,and is a better additive for coal-oil slurry.