Laboratory-Scale Coking of Coal−Petroleum Mixtures in Sealed Reactors

Abstract

Three highly fluid bituminous coalsfrom the Pittsburgh, Powellton, and Eagle seamswere reacted with atmospheric resid and decant oil in microautoclave reactors under nitrogen at temperatures of 450−500 °C. This exploratory study is the first step in evaluating the prospects for adding coal to delayed cokers to obtain coal-derived components in the liquid product. Subsequent hydrotreating (not studied here) of the liquid would produce a jet fuel with good stability toward pyrolytic decomposition. Coal-derived components appear in the oil fraction from coal−resid reactions at 465 °C. This reaction temperature represents a “coke jump”, in which the yield of solid, as a function of temperature, increases dramatically. This behavior is not observed when the individual feedstocks are reacted alone. Further evidence for coal−petroleum interactions in this system is exhibited by the fact that (i) the product slates from the co-coking reactions are not linear combinations of the products from the feedstocks reacted individually and (ii) the fluidity profiles of the Powellton−resid mixtures are similar to those for two interacting coking coals. The effect of changing coal with the same petroleum feedstock is minimal, although the coals are very similar in composition and properties. In contrast, changing from resid to decant oil with the same coal causes major changes in the product slate.

Comparative Study on Structural Parameters of Graphitized Coal–Petroleum Co-cokes and Pennsylvania Anthracites, with Implications for Their Use

“…The location of the reference sample, opposite end to nuclear-grade samples, is ascribed to the high anisotropic nature of this sample, implying long-range preferential orientation. The addition of coal to petroleum feed, i.e., vacuum resid or decant oil, reduces the concentration of large isochromatic units, such as flow domains, in a co-coke structure. ,,, Large isochromatic units lead to a highly anisotropic graphitic structure upon graphitization of the co-coke. The location of co-cokes in Figure is attributed to the fact that the precursor co-cokes were prepared to be deficient in anisotropic character, by adding coal to petroleum feeds, and that the structure of graphitized co-cokes carries both anisotropic and isotropic characteristics.…”

“…Although graphite occurs as natural graphite, it is also produced artificially by heat-treating graphitizable carbons to temperatures of 2500–3000 °C under inert conditions. Currently, the graphite industry uses petroleum coke as the filler constituent and coal tar pitch as a binder in the manufacture of graphitic materials. , In view of concerns pertaining to a steadily increasing cost of petroleum, the use of non-conventional precursor materials that graphitize readily is perceived as an alternative to or a way of reducing dependence upon petroleum coke. , For more than 1 decade, the Earth and Mineral Sciences (EMS) Energy Institute at The Pennsylvania State University has been investigating two parallel lines of synthesizing graphitic materials from non-conventional precursors, namely, synthesis of graphitic materials from co-cokes − and anthracites. − The co-coke is a byproduct of the Penn State co-coking process, which is the simultaneous co-carbonization of bituminous coal with petroleum-derived streams, such as fluid catalytic cracking decant oil (DO) or vacuum resid (VR), under typical delayed coking conditions.…”

Co-coking of Hydrotreated Decant Oil/Coal Blends: Effect of Hydrotreatment Severity on the Yield Distribution and Quality of Distillate Fuels

“…Previous studies have determined that the compounds present in jet fuel that are derived from coal account for improved thermal stability. [11][12][13][14][15][16][17][18]20 In this study, we were concerned to determine whether the overhead liquid distilled from the co-coking experiments would be of better quality; i.e., liquids would have more one-to three-ring aromatics, hydroaromatics, and cycloalkanes, which are desirable precursors for the production of thermally stable jet fuel.…”

“…For instance, fuel could be used as a primary coolant for onboard heat sources, such as the engine lubrication oil, hydraulic fluid, environmental control system, avionics and electrical systems, and airframe. , If employed in such an application, conventional jet fuel (JP-8) would be stressed to temperatures above its thermal stability. This, in turn, leads to fuel degradation, followed by gas formation and solid deposition in the fuel lines and burner nozzles. , In a multi-phase 20 year program, we developed such a multi-functional jet fuel from coal-based precursors. ,− Throughout the development, it has been shown that coal is a good precursor from which to produce hydrocarbon components that will make the fuel thermally stable, i.e., partially saturated two-ring compounds. − ,− Key advantages of using coal as a starting material are strategically important for long-term security (in the U.S., coal is a secure, domestic energy source) and stable procurement (coal is less vulnerable to price spikes than petroleum).…”

Characterization of Chars Obtained from Co-pyrolysis of Coal and Petroleum Residues

“…There are few references in the literature on this subject because most of the works on co-utilization of coal and petroleum residues are related to catalytic coprocessing reactions using high hydrogen pressures. Tomic and Schobert, 13 Martin et al, 14 and Fickinger et al [15][16][17] studied coal/petroleum resid interaction during co-processing under nitrogen and noncatalytic conditions using a lab-scale simulated delayed coker and at temperatures lower than 450 °C.…”