Coal-based solar thermal fuels: A novel perspective on clean utilization of coal tar

Process intensification, especially the clean utilization processing of coal tar, is significant for the development of coal-based fine chemicals. However, coal tar is traditionally hydrogenated by full-fraction hydrotreating to prepare gasoline and diesel oil, which leads to underutilization of key components and lack of process intensification innovations. Therefore, the combination of coal tar with sustainable solar energy along with the emerging enhanced separation and conversion of polycyclic aromatic hydrocarbons is expected to open up a new way for the clean utilization of coal tar in chemical production. For the aromatic-rich coal tar distillation section, the phenolic compounds are separated first, and the aromatic hydrocarbons are then directed to prepare solar thermal fuels, which not only reduces the hydrogen consumption of the whole process, but also has a high yield of the target product, which greatly improves the added value of the product. Recently proposed coal-based solar thermal fuels can provide storage energy densities up to 0.3 MJ kg −1 and on-demand controllable heat release through reversible transformation of the molecular structures, showing great potential for applications in smart wearable and circulating heating. The process of coal-based solar thermal fuels’ production involves component analysis, separation and chemical synthesis, and its process intensification innovations would help to improve the clean and efficient utilization of coal tar.