Coal pyrolysis is an efficient route for the clean utilization of low-rank coals due to its producing scarce gas and oil resources.This paper focuses on the key technical problems of the unmanageable yield and quality of tar and the high dust content in tar.From coal pyrolysis mechanism

the types and occurrence conditions of volatile secondary reactions and the major influence factors on pyrolysis are discussed in detail.Combining the application of coal pyrolysis technology

it is summarized that gas phase secondary reactions of volatiles are responsible for the decrease of tar yield.Meanwhile

the coal particle fragmentation mechanism and the source of dust during pyrolysis are analyzed.Based on previous research results

we propose that the control methods for coal pyrolysis process

such as changing volatile flow direction from high temperature zone to low temperature zone

coupling pyrolysis with gasification and in situ tar upgrading and dust removal

which can inhibit heavy tar formation

improve light tar content and reduce dust content in tar

and thus realize oriented coal pyrolysis.