The effect of the initial water of lignite on its liquefaction reactivity
In this paper, the effect of different initial water content of lignite on its direct liquefaction reactivity was studied. The results show that: initial water content in lignite can be used as hydrogen supplier and promote direct liquefaction reaction inducing higher total conversion rate, higher oil yield and lower pre-asphaltene / asphaltene yield, when the water content of lignite is of 20 ~ 30%. And the maximum of total conversion rate and oil yield is achieved 85.12% and 51.72%, respectively, when the water content of lignite is 25.33%. While the gas product yield and the pre-asphaltene /asphaltene yield is relatively lower, which is of 11.16% and 3.93%, respectively. This can be of practical significance to optimize the coal pre-treatment technology of direct liquefaction industry.
Relevance of cleavage of strong bonds in coal liquefaction
Almost ten years ago we proposed that cleavage of bonds too strong to undergo simple thermolysis but which are cleaved by the mediation of solvent or solvent-derived radicals may be an important contributor to the liquefaction of coals. In this paper we discuss the process implications of this revised view. We show how this picture continues to help rationalize many otherwise inexplicable observations in fossil fuel conversion technology. These observations include the breaking of nonhomolyzable bonds in grafted and doped coals, the ineffectiveness (in liquefaction) of nonhydroaromatic radical scavengers, the effectiveness of nondonor polycyclic aromatic hydrocarbons (PAH), the «activation» of cyclic aliphatics by PAH, increasing hydrogen utilization efficiency observed with added PAH, and the decrease in gas formation observed at lower temperatures or with added PAH
Catalysis and catalyst dispersion in coal liquefaction
The Bergius process for the hydroliquefaction of coal 80 an 80-year history. This selective review attempts to trace the role of catalysis, and especially of catalyst dispersion, in this process. The metals commonly used in liquefaction catalysts, iron, molybdenum, and tin, were discovered and utilized in large-scale plants in Germany and England well before World War II. The usefulness of achieving high dispersion, and therefore high interfacial contact of catalyst with coal, coal-derived liquids, and hydrogen, was demonstrated in autoclave and pilot plant experiments during the early 1950s. Research since then has followed several themes. Although impregnation of catalyst on coal was recognized early as one method of achieving high dispersion, the cost of impregnation led to studies of other methods