Showing papers in "Preprints-American Chemical Society Division of Petroleum Chemistry in 1998"

Shape-selective isopropylation of naphthalene over mordenite catalysts : Computational analysis using MOPAC

Abstract: The results from our laboratpory show that by using partially dealuminated mordenite catalysts, shape-selective alkylation of naphthalene can be achieved with over 65% selectivity to 2,6-DIPN by using isopropanol with 2,6-DIPN/2,7-DIPN ratio of about 3, or using propylene as the alkylating agent with 2,6-DIPN/2,7-DIPN ratio of >2

Mechanism of thiophene hydrodesulfurization on model molybdenum catalysts

Abstract: Removal of organosulfur compounds from petroleum is accomplished by hydrodesulfurization (HDS) in which the petroleum is reacted with hydrogen on a supported metal sulfide catalyst. The typical catalyst consists of cobalt-promoted molybdenum disulfide supported on γ-alumina

Commercial utility of naphthenic acids recovered from petroleum distillates

Abstract: Naphthenic acids are a naturally occurring, complex mmixture of cycloaliphatic carboxylic acids recovered from petroleum distillates. They have unique properties that can be exploited in many performance-oriented applications requiring excellent oxidative stability and compatibility, high solubility in hydrocarbons and oils, and low solubility in water. Annual North American naphtenic acid consumption was estimated at 20 million pounds in 1996, growing to 22 million pounds by 2000. Although naphthenic acid has been an item of commerce for over seventy-five years, recent market factors have significantly changed its end uses. Their major uses are in oil-soluble metal soaps for driers and other catalysts, wood preservatives, and tire cord adhesion promoters, and in amine derivatives for corrosion inhibitors. This overview will focus on the primary market uses of naphthenic acid, examine the major market forces which affect production and sales, and offer some background information on occurrence, production, and chemistry.

Estimation of sulfur content of petroleum products and crude oils

Abstract: The main objective of this work is to propose a method for accurate estimation of the amount of sulfur in a crude oil or various petroleum products and fuels using easily measurable or readily available properties.

Challenges in the characterization of naphthenic acids in petroleum

Abstract: Limited characterization data exists on naphthenic acid compounds and group-types. This paper reviews those data and identifies areas where additional characterization is needed.

Indirect coal liquefaction : Where do we stand?

Abstract: Following its discovery by Fischer and Tropsch, the desirability of conversion of synthesis gas to hydrocarbons has undergone many cycles ranging from the view that there was an immediate, urgent need for commercialization to periods of benign neglect. In the 1930s, because Germany did not have an internal source of petroleum, but did have a vast reserve of coal, interest in Fischer-Tropsch Synthesis (FTS) was great. Germany developed a significant synfuels industry prior to and during WWII. However, their total peak production was small-scale in comparison to the US consumption of petroleum today. Furthermore, much of the German transportation fuel was derived from coal tars and direct coal liquefaction rather than from FTS. During WWII, the German FTS production was mainly conducted at atmospheric pressure using cobalt catalysts in fixed-bed reactors. Following WWII there was a perceived shortage of petroleum crude. In many countries, crash programs to develop a synfuels industry were initiated. US officials were among those who recognized the potential limits of petroleum crude. Major efforts were directed toward developing the Fischer-Tropsch (F-T) synthesis processes in the US. This paper reviews the history of the development of F-T synthesis processes using both coal and natural gas as feedstocks,more » and describes today`s commercial operations, large demonstration plant operations, research by Standard Oil Co. (now Exxon), pilot scale operations, process and economic evaluations, and potential commercial operations. 85 refs., 25 figs.« less

Corrosion by naphthenic acids in crude oils

Abstract: It is likely that parts of the organic acid molecule other than the carboxylic group also play a part in the corrosivity of the acid. No clear pattern relating corrosivity to acid molecular weight or structure has yet been established. The relationship appears to be a very complex one.

Reactivities of several carbonaceous materials for their combustion catalyzed by potassium salts on perovskite type oxide : Chemistry of diesel fuels

Abstract: In the present study, the catalytic activities of potassium sulfate and carbonate supported on the perovskite type oxide were examined for the combustion of several carbonaceous materials such as activated carbon, carbon black, graphite and coal chars. Influence of reaction temperature on the catalytic combustion and heat treatment temperatures of coal chars on their reactivity were examined

Mass spectrometric characterization of acids in crude oils

Abstract: Naphthenic acids, originally defined as acidic components in curde oils having single to multiple condensed saturated ring structures, have been loosely defined as all acidic components in crude oils that may even contain aromatic functionality. Their presence in crude oils is of concern due to their corrosivity to refinery units.

The relationship between biodegradation, total acid number (TAN) and metals in oils

Abstract: Carboxylic acids are known to be by-products of petroleum biodegradation. Acids and metals in oils poison catalysts used during oil refining. It is thus important to understand the factors affecting the contents and the nature of metals and acids. Oils were selected which were at different stages of biodegradation and which were from different geographic and geological environments. We sought to observe if there was a clear relationship between degree of biodegradation and TAN (total acid number). As Fe was observed to be present at relatively high concentrations in many biodegraded oils, we sought to determine if this metal was associated with naphthenic acids. Some work was done to determine the nature of the acids in a severely biodegraded oil.

Formation of carbonaceous deposits in a model jet fuel under pyrolysis conditions : Structure of jet fuels V

Abstract: Recently, the mechanism responsible for the formation of graphitic carbon was studied under conditions where a normal alkane fuel is heated to 700°C. This report suggests that the mechanism consists of two steps, ring formation and ring growth. The goal of this work was to determine if the mechanism proposed by Nohara and Sakai could be responsible for coke formation under the supercritical conditions proposed in high speed aircraft.

Effect of test period on the rate of fouling in a complex flowing system : Structure of jet fuels V

Abstract: The objective of this experimental work is to better understand the effects of the test period on the rate of surface fouling under thermal and flow conditions similar to those which might be found in future high-performance aircraft.

Characterization and classification of gas oils by mass spectrometry/ chemometrics for application in fluid catalytic cracking

Abstract: Gas oils for fluid catalytic cracking (FCC) contain an immense number of different hydrocarbon compounds that directly impact their chemical/physical properties and FCC catalysts performance. In recent years, refineries and catalyst manufacturers have become interested in developing correlations among feed composition and catalyst properties, in order to optimize FCC cracking conditions and catalyst selection strategies.

Comparison of acid numbers and carboxylic acid molecular compositions in biodegraded and normal crude oils

Abstract: Increases in the overall acidity in crude oils as a result of biodegradation processes have been generally observed. However, knowledge of the types of acidic compounds involved is lacking, and this reflects a lack of understanding of the acidification processes on a molecular level. This work investigates the correspondence of the titrated acid numbers in biodegraded oils with other measures of oil quality, and with analysis of molecular acidic components in a set of oils from the norwegian continental shelf. The co-existing brines have also been analyzed, and relationship between aqueous and oil-phase acids can thus be evaluated.

Chemical structure analysis of Shengli crude vacuum residuum related to thermal conversion

Abstract: The objective of this study was to use the ruthenium ions catalyzed oxidation (RICO) method for characterization of detailed chemical structure changes of resins and asphaltenes of Shengli vacuum residuum before and after thermal conversion. The same analytical procedures were also applied to the toluene-insolubles formed during the thermal conversion.

A novel concept of catalyst design - Sulfur-resistant noble metal catalysts based on shape-selective exclusion and hydrogen spillover

Abstract: The noble metal catalysts with high sulfur resistance, if they can be developed, will allow hydrotreating at substantially lower pressure which can lead to a major improvement on therefining efficiency and economics. recent research has shown that noble metals may be rendered less sensitive to sulfur when supported on certain materials.

Formation of the physical neophase in terms of SARA compositions of vacuum residua

Abstract: Real-time optical microscopy monitoring of the physical progress of the thermal reaction systems of vacuum residua derived from three representative Chinese petroleum, Daqing, Shengli and Gudao crudes has demonstrated that three different kinds of neophases occur sequentially as the residence time extends.

Cyclic species formation in the fuel systems of hydrocarbon fueled high-speed vehicles : Structure of jet fuels V

Abstract: The present contribution addresses the formation of cyclic species in the thermal decomposition of hydrocarbons commonly found in endothermic fuels.

Modeling of pyrolysis and pyrolytic deposition of Norpar-13 under supercritical conditions : Structure of jet fuels V

Abstract: In the present study, pyrolysis and pyrolytic deposition of Norpar-13 under high pressure and relatively low temperature (<600°C) conditions are investigated both experimentally and numerically.

Photocatalytic recycling of H2 in hydrodesulfurization

Abstract: Environmental regulations have required oil and gas refineries to develop waste minimization technologies for the treatment of sulfur-containing compounds, principally hydrogen sulfide, H 2 S, within their facilities. In this report, a new tail gas sulfur recovery process is described in which the H 2 S, having been absorbed into an alkaline solution, is decomposed in an energy-storing solar photochemical scheme to yield not only sulfur, but also hydrogen that can be sold or used internally at the refinery.

Highly efficient and regioselective cyclization catalyzed by TS-1

Abstract: In this paper we report a highly efficient regioselective cyclization of such olefinic alcohols over TS-1, under mild reaction conditions using dilute hydrogen peroxide as oxidant. Similar types of oxidative cyclization (bifunctional behavior, epoxidation followed by acid catalyzed cyclization) was observed in the oxidation of linalool over Al-Ti-Beta and Al-Ti-MCM-41 where the acidity at the Al sites was responsible for the cyclization.

Reaction kinetics of Venezuelan naphthenic acids with high surface iron

Abstract: This paper will focus only on the reaction kinetics of naphthenic acids found in Venezuelan distillation cuts with high surface pure iron, not considering sulfur effects. it was possible to study the reaction order with respect to the acid and kinetic data was achieved. Furthemore, the lack of correlation between TAN and corrosivity was explained, since the polarity and/or the acid stregth of naphthenic acid molecules seem to play a relevant role on the naphthenic corrosion.

Kinetics of deposit precursors in jet fuels : Structure of jet fuels V

Abstract: With advances in jet engine technology and the quest to reach higher mach numbers, fuel stability is expected to play a significant role in the thermal management of modern aircraft. As system temperatures increase, the fuel autoxidation process that forms peroxides, soluble gums and deposits will be greatly accelerated. Fuels will be exposed to higher temperatures for longer periods of time because there will be an increased demand on the cooling capacity of the fuel.

Studies of hydroperoxide decomposing species for inhibiting oxidation in jet fuels : Structure of jet fuels V

Abstract: In the present study, we explore the role that hydroperoxide decomposers play in slowing and/or delaying autoxidation of jet fuel. We also study the synergism of these species with other additive types. In addition, pseudo-detailed chemical kinetic modeling was performed insight into the chemicel mechanism of additive behavior.

Mesoporous aluminosilicate molecular sieve MCM-41 as support of Co-Mo catalysts for deep hydrodesulfurization of diesel fuels : Chemistry of diesel fuels

Abstract: This work explores the potential of MCM-41 as support for Co-Mo catalysts at two different metal loading levels for deep desulfurization of distillate fuels such as diesel and jet fuels where conversion of polycyclic sulfur compounds is necessary.

Computational modeling on hydrodesulfurization of thiophenic compounds on MoS2 and Ni-promoted MoS2

Abstract: Since fundamental understanding of the HDS mechanism on such catalysts is essential for the development of new deep HDS processes and efficient catalysts, considerable effort in aspects of the reaction kinetics of model compounds, characterization of catalyst surface, coordination chemistry of organometallic complexes and molecular simulation, respectively, has been devoted to the HDS mechanism of thiophenic compounds.

The chemistry of coke formation from petroleum : A tutorial : Chemistry of coking, desirable and undesirable

Abstract: When petroleum is heated at elevated temperatures for a very long time, it decomposes into gases and a solid with little or no liquid. This resulting black solid that is insoluble in any solvent and cannot be melted at any temperature, we call coke.

Chemistry of petroleum residues in the presence of H-donors : Chemistry of coking, desirable and undesirable

Abstract: In the present study, the effect of hydroaromatics on the optical texture of coke and on the induction period for mesophase appearance during hydrocracking was investigated using hot-stage microscopy.

Separation and characterization of nitrogen compounds in petroleum vacuum residues

Abstract: This paper reports the development of a method to separate heavy oils. The four vacuum residues were separated into fractions of hydrocarbons, acids, bases and neutral nitrogen compounds by adsorption chromatography on basic and acid alumina. The results ashowed that most of acidic compounds were concentrated in acids and most basic nitrogen compounds in bases. Fractions were analyzed by non-aqueous potentiometric titration and infrared spectroscopy.