Research On The Coal Tar Decontamination And Reactions Of Coal Tar Hydrogenation

China is one of the largest coal producers in the world and extensive studies havebeen focused on the fuel production from coal. Abundant coal tar has been producedduring coal carbonization and gasification every year. Through its hydrogenation，thecoal tar can be used as an alternative source for producing conventional liquid fuels（such as gasoline and diesel）. Now, energy is short in China. through catalytichydrogenation technology of coal tar into effective for high heat value of gasoline anddiesel fuel, will be helpful to alleviate our country the sources of energy shortagesituation, and make a positive significance for environmental protection. The maincontent of present paper was focused on the items as follows1. By doing lots of experiments of compounding polyether demulsifiers, find the bestprescription, and do emulsion breaking and dehydration on coal tar.2. Special hydrofining （such as MoCo/γ-Al₂O₃） catalyst and hydrocracking （such asWNi/γ-Al₂O₃-USY） catalyst with different metal loadings were prepared applyingthe synthesis technologies of ultrasonic-assisted impregnation andtemperature-programming calcination methods. Clean liquid fuels were obtainedfrom middle-temperature coal tar via hydrogenation in two-stage fixed beds filledwith the laboratory made catalysts.3. ICP-AES,BET, XRD, SEM, TEM, etc., were employed to characterize thecatalysts. Analysis results showed that the active metals and promoters werehighly dispersed on the catalyst supports.4. Gasoline （≤180℃） and diesel （180–360℃） fractions were separated from the rawoil product, some indexes such as sulfur and nitrogen contents, distillation range,RON for gasoline and cetane number for diesel, etc., were analyzed. The effects ofpressure and liquid hourly space velocity on hydrogenation performance wereinvestigated. Gasoline and diesel fractions with sulfur and nitrogen contents ofaround40ppm and10ppm were obtained at the experimental conditions of PH2=6-10MPa, Thf=360℃, Thc=380℃, LHSV=0.4-1.2h-1and H₂/oil ratio=1600,compared with the sulfur and nitrogen contents of0.98wt.%and1.69wt.%in the coal tar feed.5. GC-MS analyses revealed that the gasoline product was mainly composed of C6-C12hydrocarbons, such as substituted cyclohexanes,substituted and partiallysaturated naphthalenes, and the diesel product mainly consisted of substituted andpartially saturated naphthalenes and paraffins with high carbon number as well aslow content of polycyclic aromatics.6. Cost analysis showed that coal tar hydrogenation should be economicallypromising for industrial application.