Collision-induced dissociation Fourier Transform ion cyclotron resonance mass spectrometry (CID-FTICR MS) was developed to determine structural building blocks in heavy petroleum systems. Model compounds with both single core and multicore configurations were synthesized to study the fragmentation pattern and response factors in the CID reactions. Dealkylation is found to be the most prevalent reaction pathway in the CID. Single core molecules exhibit primarily molecular weight reduction with no change in the total unsaturation of the molecule (or Z-number as in chemical formula C(c)H(2c+Z)N(n)S(s)O(o)VNi). On the other hand, molecules containing more than one aromatic core will decompose into the constituting single cores and consequently exhibit both molecular weight reduction and change in Z-numbers. Biaryl linkage, C(1) linkage, and aromatic sulfide linkage cannot be broken down by CID with lab collision energy up to 50 eV while C(2)+ alkyl linkages can be easily broken. Naphthenic ring-openings were observed in CID, leading to formation of olefinic structures. Heavy petroleum systems, such as vacuum resid (VR) fractions, were characterized by the CID technology. Both single-core and multicore structures were found in VR. The latter is more prevalent in higher aromatic ring classes.

In this paper, density functional theory is used to estimate hydrogen adsorption in a novel carbonaceous material, single-walled carbon nanotubes. An idealized adsorbent structure for the nanotubes is assumed. We have mapped out the regime of operating pressures and temperatures where an adsorption-based storage system is expected to deliver more hydrogen than a similar system of compressed gas. This regime is also a function of pore size. We have calculated the overall hydrogen volumetric and gravimetric density within the framework of a typical high-pressure gas storage system. Within the regime of operating conditions where adsorptive storage seems attractive, the storage properties of hydrogen in a carbon nanotube system appear to fall far short of the targets of 62 kg of H2/m3 and 6.5 wt % H2 set by the Department of Energy. The computed gravimetric storage densities also fall short of those reported in the literature (Nature 1997, 386, 377). We discuss several possible mechanisms by which higher gravimetric density could be rationalized, including chemisorption, adsorption at interstitial sites, and swelling of the nanotube array.

The properties of alkanes in the C20–C40 mass range are of fundamental importance in industrial applications as they are important constituents of synthetic lubricant base stocks. In an extension to earlier work on alkanes in the C20–C40 carbon number range we present the results of molecular simulations for 9-octylheptadecane, a starlike isomer of C25. Both equilibrium (EMD) and nonequilibrium molecular dynamics (NEMD) simulations have been performed under ambient state conditions and to pressures in the gigapascal range. The EMD simulations focus on calculations of the rotational relaxation times, while the NEMD simulations reveal the dependence of the viscosity on strain rate. Additionally, we calculate the viscosity number and pressure–viscosity coefficient for 9-octylheptadecane and compare the results with those obtained experimentally.

A computational procedure using a modification of Boston and Sullivan's "inside-out" multistage multicomponent separation algorithm (1974) is developed. In order to improve convergence behavior for problems involving mixtures with highly nonideal liquid phases, a two-parameter model is used to describe liquid-phase compositional effects upon the K-factor. The quasi-Newton methods of Mehra et al. (1983) and Nghiem (1983) are applied to solving various sets of solution variables in the proposed algorithm. Activity coefficients are calculated using the UNIQUAC activitycoefficient model (1975) with parameters obtained from the UNIFAC group-contribution method (1975). The computational procedure is applicable to distillation, absorption and reboiled-absorption configurations. The proposed algorithm was implemented in a FORTRAN 77 program and tested on the Honeywell DPS 8/70M computer at the University of Calgary. Inclusion of the liquid-phase model resulted in improved convergence behavior for nonideal systems in which the original "inside-out" method failed to converge.On a ttabli une mtthode de calcul impliquant une modification de I'algorithme "inside-out" de Boston et Sullivan (1974) pour la sCparation multittagke des mClanges complexes. Pour amtliorer la convergence dans le cas de probltmes faisant intervenir des mtlanges avec des phases liquides fortement non-idtales, on utilise un modtle B deux paramttres pour dtcrire les effets de la composition de la phase liquide sur le facteur K. Les mtthodes quasi-Newtoniennes de Mehra et coll. (1983) et Nghiem (1983) sont appliqutes a la dsolution de plusieurs series de variables dans I'algorithme propost. Les coefficients d'activitt sont calculCs a I'aide du modtle de coefficient d'activitt UNIQUAC (1973, les paramttres ttant obtenus par la mtthode contribution de groups UNIFAC (1975). Cette mCthode de calcul est applicable ? i des systkmes de distillation, d'absorption et d'absorption avec rebouilleur. L'algorithme propost a Ctt intCgrt dans un programme FORTRAN 77 et test6 sur I'ordinateur Honeywell DPS 8/70 M de I'universitt de Calgary. L'inclusion du modkle pour la phase liquide a permis d'amtliorer le comportement de la convergence pour des systkmes non-idtaux dans lesquels la mCthode "inside-out" ne converge pas. large number of solution methods for single column A simulation are reported in the literature. In choosing a 760

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