The effect of addition of several solvents on atmospheric residue (AR) hydrotreating was examined in the autoclave test. Higher hydrodesulfurization (HDS) activity was obtained by adding solvents in the order of H₂O > light cycle oil (LCO) > tetralin > none (base) > 1-MN > phenol, using the same volume of solvent. The amount of deposited coke on the catalyst was reduced with all solvents. Larger amounts of tetralin enhanced HDS activity, but tetralin was still inferior to water for the enhancement of HDS in the same molar amounts. The specific effects of H₂O were confirmed through the activity test. The amount of deposited coke on catalyst with tetralin was similar to that of H₂O. Enhancement of asphaltene desorption reduces coke formation on the catalyst whereas the hydrogenative conversion of solvents with sulfur species in AR may indicate competitive occupation on the active sites. Solvents were not only hydrogenated but also contributed to inhibition of HDS when remaining for long periods on the active sites. Consequently, the inhibition effects of the solvents were considered based on the conversion and evaluation results. H₂O enhances the desorption of asphaltene and desulfurized products from the catalyst compared with the other solvents. The remarkable effects of H₂O addition are due to remaining on the active sites for short periods, without inhibiting the HDS activity.

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Dynamic behavior for breakup of a single water drop and coalescence among multiple water drops falling through an oil phase were experimentally studied in a novel electrodynamic liquid-liquid contactor, which was developed for use as a large-scale practical electrodynamic desalter for crude petroleum. (1) In the experiment of a single water drop, the effects of electric field strength on elongation rate of the drop, breakup mechanism of the drop and the number of the breakup drops were investigated. It was found that the dynamic breakup of the drop could be grouped into three types depending on the strength of the electric field. (2) In the experiment of multiple water drops, the effects of interacting range of their positions and the electric field strength on drop-drop coalescence between the main drop and surrounding drops were examined. Droplet-chains formed by multiple water drops falling between the electrodes and the resulting formation of a water bridge, which cause operational problems in desalters, were simulated experimentally, and their formation process and their shapes were traced.

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Production planning for multi-site batch plants to maximize total profits should establish simultaneous allocations to the plants considering available production times and transportation of products from the plants to the distribution centers. Since some intermediate products of batch plants are unstable, combining products often reduces the cycle times. Therefore, production sequences are required to estimate production times, but production sequences depend upon allocation, which cannot be determined without estimation of production times. A straightforward mathematical formulation for such production planning results in a mixed-integer non-linear programming (MINLP) problem, which may require excessive computational time even for small problems. Optimal production planning requires that allocations for each batch plant are produced based on product combinations (product mixes), of which only the productivities are improved. This study introduced product mixes as the units of allocation. The method of allocation is to determine the optimal numbers of individual product mixes for each batch plant. Cycle times of product mixes are constant, so the required production time at each plant may be approximated as the sum of the cycle times of product mixes. Based on product mixes with predetermined cycle times, manufacturing costs, and transportation costs, the mixed-integer linear programming (MILP) problem is solvable and can simultaneously establish the allocation and the transportation of products with maximum total profits. The effectiveness of this proposal is demonstrated through an example problem.

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The structural characteristics of the components of several vacuum residues from different geological sources (Taching, Sumatra light, Iranian heavy, Arabian mix, and Murban vacuum residues) were investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) without chromatographic pre-separation. The present approach can detect basic nitrogen compounds in vacuum residues with high selectivity. The mass spectra showed differences in both average and range of molecular weights depending on the origin. Accurate masses were used to estimate molecular formulas. All observed peaks were assigned to mononitrogen-containing compounds (major components) or both mononitrogen- and monosulfur- containing compounds (minor components). Homologue analysis for all estimated molecular formulas showed the analogies and peculiarities in components of the five vacuum residues. Every observed compound was sorted by hydrogen deficiency index (Z-value: [C_nH_{2n + Z}N_mS_s+H]⁺) and carbon number. The distribution center of the Z-values depended on the vacuum residue origin and the maximum value decreased as follows: Taching (−17) > Sumatra light (−19) > Iranian heavy (−21) ≥ Arabian mix (−21) > Murban (−25). Taching vacuum residue contained low absolute Z-values compared to the other vacuum residues from the Middle East. The results obtained by ESI FT-ICR MS were in good accordance with reported findings of highly condensed aromatic compounds in Middle East vacuum residues contains compared to Chinese vacuum residues.

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Dimethyl terephthalate was hydrogenated over ZrO₂ catalyst in the vapor phase to form terephthalaldehydic acid methyl ester and terephthalaldehyde as the major products. The reactivity of the three regioisomers of benzenedicarboxylic acid dimethyl esters to hydrogenation was in the order, terephthalic > isophthalic >> phthalic. The low reactivity of dimethyl phthalate is probably due to the mutual steric hindrance of the two vicinal methoxycarbonyl groups and to catalyst deactivation caused by strong adsorption of the intermediates of dimethyl phthalate on the catalyst surface. Formation of terephthalaldehyde by hydrogenation of terephthalaldehydic acid methyl ester suggested that the hydrogenation reaction of dibasic acid diesters proceeds via successive reduction of the ester groups to formyl groups. Alicyclic acid diester dimethyl 1,4-cyclohexanedicarboxylate was also converted into the corresponding mono- and dialdehyde in a similar way. However, aliphatic dibasic acid esters such as dimethyl glutarate and dimethyl adipate were not hydrogenated at all. Modification of ZrO₂ by Cr, In or Zn improved the catalyst activity. Maximum dialdehyde selectivity in the hydrogenation of terephthalaldehydic acid methyl ester reached 72.4% by using Zn modified ZrO₂ catalyst (atomic ratio Zn/Zr = 5/100).

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The adsorption species on ZrO₂ or Cr-ZrO₂ catalyst in the hydrogenation of dimethyl benzenedicarboxylates as well as benzoic acid were characterized by diffuse reflectance FT-IR and CP/MAS ¹³C-NMR spectroscopy. Benzoic acid and dimethyl terephthalate were adsorbed as the monocarboxylate species with weak bonding to the catalyst with lower polarization at a carbonyl group similar to that of free benzoic acid. In contrast, dimethyl phthalate was adsorbed only as the dicarboxylate species. Dimethyl isophthalate was adsorbed as both mono- and dicarboxylic species. Formation of dicarboxylate adsorption species will greatly hinder the hydrogenation of dimethyl benzenedicarboxylates. In addition, the methoxycarbonyl group was more favorable for the adsorption to form the carboxylic active species than the formyl group in the interaction of Cr-ZrO₂ catalyst with terephthalaldehydic acid methyl ester. A reaction mechanism for the hydrogenation is also proposed.

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Isomerization of light naphtha containing sulfur compounds was investigated over metal/SO₄²⁻/ZrO₂-Al₂O₃ catalysts, and the appearance of sulfur tolerance was discussed using the analysis of the metal distribution in the sulfur-tolerant isomerization catalysts. Although the isomerization activity of the conventional Pt/SO₄²⁻/ZrO₂-Al₂O₃ catalyst decreased linearly in the presence of sulfur in the feed, the Pd-impregnated Pt/SO₄²⁻/ZrO₂-Al₂O₃ catalyst, in which Pd was added to the Pt/SO₄²⁻/ZrO₂-Al₂O₃ carrier, maintained stable isomerization activity even in the presence of high concentrations of sulfur. EPMA (Electron Probe Micro Analysis) investigation of the metal distribution indicated that a hybrid structure (Pt/SO₄²⁻/ZrO₂-Pd/Al₂O₃) was formed in the Pd-impregnated catalyst, and that the high sulfur tolerance of the catalyst originated in the desulfurization function of the Pd/Al₂O₃ particles formed in the catalyst. To investigate the effect of the Pd/Al₂O₃ particles, isomerization was carried out over a powder mixture of Pt/SO₄²⁻/ZrO₂-Al₂O₃ catalyst and Pd/Al₂O₃ catalyst. Since the powder mixture catalyst also showed sulfur tolerance equal to the Pd-impregnated Pt/SO₄²⁻/ZrO₂-Al₂O₃ catalyst, it was suggested that the Pd/Al₂O₃ particles supply hydrogen to the Pt/SO₄²⁻/ZrO₂-Al₂O₃ particles in addition to catalyzing hydrodesulfurization. Moreover, the lifetime test showed that the sulfur tolerance of Pd-impregnated Pt/SO₄²⁻/ZrO₂-Al₂O₃ catalyst was maintained in the long term, and that products with higher octane number could be obtained stably even from the isomerization of sulfur-containing light naphtha.

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A novel type of photo-operated biofuel cell was based on the combination of NAD⁺ reduction with glucose and GDH, with photosensitization of zinc chlorin-e₆ (ZnChl-e₆) as a model of chlorophyll a on a nanocrystalline TiO₂ film electrode as the anode, and electrochemical reduction of oxygen to the water on a platinum electrode as the cathode. The short-circuit photocurrent (I_SC) and the open-circuit photovoltage (V_OC) were 6.8 μA·cm⁻² and 444 mV, respectively. The peaks in the photocurrent action spectrum of this cell were observed at 400 and 780 nm, and the IPCE values at 400 and 780 nm were estimated to be approximately 11.0 and 6.2%. This novel type of photo-operated glucose-O₂ biofuel cell depends on the visible and near IR photosensitization of ZnChl-e₆ molecules on nanocrystalline TiO₂ film electrode.

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