Amount Of Pentane Research Articles

Synthesis of core-shell PS/PMMA expandable particles via seeded suspension polymerization

Expandable core-shell beads were synthesized by dosing methyl methacrylate (and styrene) in a constant rate and polymerizing in the presence of polystyrene seeds and pentane. The morphological studies of beads indicated that there were larger poly(methyl methacrylate)-rich domains near the shell. The sizes of these domains were decreased towards the core of the particles. For better surveying the likely structures of domains and the extent of expansion agent diffusion, the beads having the shells formed with copolymerization of styrene and methyl methacrylate in the presence of polystyrene seeds were studied. From the morphological studies, the parallel regular and the onion-like structures were recognizable. In addition, another shell was formed around the dispersed phase showing a complex core/shell structure both in particle and in domain scales. The pentane content in the beads with copolymerized styrene and methyl methacrylate monomers on the polystyrene seeds was increased compared to the beads having the shells of pure poly(methyl methacrylate). This was because the onset of gel effect was longer with adding the styrene to methyl methacrylate monomer hence there was more time for expansion agent to diffuse into the beads. The different amounts of pentane distributed in polystyrene- and poly(methyl methacrylate)-rich phases were discussed in terms of the changes in glass transition temperature of two phases.

P−ρ−TBehavior of Four Lean Synthetic Natural-Gas-Like Mixtures from 250 K to 450 K with Pressures to 37 MPa

The p−ρ−T behaviors of four lean synthetic natural gas mixtures were measured along isotherms of 250 K, 350 K, and 450 K with pressures to 37 MPa with a two-sinker, magnetic-suspension densimeter. The gravimetrically prepared mixtures have seven to nine components (methane to pentane). They are all nominally 0.90 mole fraction methane, and they differ primarily in the amount of pentane and isopentane and the presence or absence of nitrogen and carbon dioxide. The analysis for density accounts for the force transmission error in the magnetic suspension coupling (MSC) of the densimeter and the magnetic effects of the fluid. These data are compared to the GERG 2004 and AGA-8 models for natural gas mixtures. The densities calculated by both the models are generally in very good agreement with the data, with average deviations less than 0.05 %, at the higher temperatures (T = 350 K and T = 450 K) and lower pressures (p < 15 MPa). But at higher pressures and lower temperatures, the average deviations are substantially larger, ranging up to 0.28 % and 0.93 % for the GERG 2004 and AGA-8 models, respectively, for T = 250 K and p > 15 MPa for one or more of the mixtures. Additional data on these same mixtures were measured by Texas A&M University and are reported in a previous paper.

Viscosity and Density Correlations for Hydrocarbon Gases and Pure and Impure Gas Mixtures

In this work, newly developed correlations for hydrocarbon gas viscosity and density are presented. The models were built and tested using a large database of experimental measurements collected through extensive literature search. The database covers gas composition, viscosity, density, temperature, pressure, pseudoreduced pressure and temperature and compressibility factor for different gases, and pure and impure gas mixtures containing high amount of pentane plus and small concentration of nonhydrocarbon components. Gas viscosity and gas density models were built with 800 randomly selected data points extracted from the large database. The models were developed using the Alternating Conditional Expectations (ACE) algorithm. The models' accuracy was validated using the rest of the database, and their efficiency was tested against some commonly used correlations. The developed models seemed very efficient and they accurately predicted the experimental viscosity and density measurements, overcoming several constraints limiting the other correlations' accuracy with average absolute errors of 3.95% and 4.93% for the gas viscosity and gas density models, respectively. Sensitivity analysis of the proposed gas viscosity model indicated the positive impact of density and pseudoreduced temperature and the trivial impact of pseudoreduced pressure. The gas density model was found to be sensitive to all input parameters of pseudoreduced temperature, apparent molecular weight, and pseudoreduced pressure listed on the order of their impact. Negative impact was predicted for reduced temperature, whereas positive ones werenoticed for the pseudoreduced pressure and gas apparent molecular weight.

Novel Density and Viscosity Correlations for Gases and Gas Mixtures Containing Hydrocarbon and Non-Hydrocarbon Components

Abstract Hydrocarbon gas often contains some amounts of heavier hydrocarbon and non-hydrocarbon components that contribute to its properties (i.e. viscosity and density). Prediction of the density and viscosity values for hydrocarbon gases is necessary in several hydrocarbon gas engineering calculations such as the calculation of gas reserves, gas metering, gas compression, estimating the pressure gradient in gas wells and for the design of pipeline and surface facilities. Literature correlations for the density and viscosity of pure hydrocarbon gas such as methane, ethane, propane, butane and isobutene are available. However, wide-ranging and accurate correlations for predicting the gas viscosity and density are not available for gas mixtures associated with heavier hydrocarbon components and impurities components such as carbon dioxide, nitrogen, helium and hydrogen sulphide. This paper presents two new models for estimating the density and viscosity of pure hydrocarbon gases and hydrocarbon gas mixtures containing high amounts of pentane, plus small concentrations of non-hydrocarbon components (i.e. carbon dioxide, nitrogen and helium), over a wide range of temperatures and pressures on the basis of fuzzy logic approach. The density model was developed using apparent molecular weight, pseudo-reduced temperature and pseudo-reduced pressure. However, the viscosity model was developed using density, apparent molecular weight and pseudo-reduced temperature. The fuzzy models were derived from 5,350 measurements of density and viscosity of various pure gases and gas mixtures. The partitioning of the input space into the fuzzy regions, represented by the individual rules, was obtained through fuzzy clustering. Accuracy of the new fuzzy models was compared to various literature correlations by blind tests using 1,460 measurements of density and viscosity. The results show that the new fuzzy models are more accurate than the compared correlations. Introduction Accurate determination of the density, viscosity and phase behaviour of pure hydrocarbon gases and hydrocarbon gas mixtures is essential for reliable reservoir characterization and simulation and, hence, for optimum usage and exploitation. The variety of possible natural gas mixtures at different conditions of interest preclude obtaining the relevant data by experimental means alone, thus, requiring the development of prediction methods. Natural gas is a mixture of many components. Wide ranging correlations for the viscosity of the lower alkanes, such as methane, ethane, propane, butane and iso-butane, have already been developed and are available in the literature(1–3). However, wide-ranging correlations are often not readily available for many of the higher alkanes and impurities such as carbon dioxide and hydrogen sulfide. These impurities may be present in small quantities in natural gas and are important when modelling the mixture properties(4). In this paper, the fuzzy logic technique was applied for developing new efficient empirical models to estimate density and viscosity of pure hydrocarbon gases (from methane to pentane) and hydrocarbon gas mixtures (different gas mixtures of methane with ethane and/or propane,...., n-Decane) containing small concentrations of non-hydrocarbon components (i.e. carbon dioxide, nitrogen and helium) over a wide range of temperatures (0–238 °C) and pressures (1–890 bar). The new models are designed to be simpler and more efficient than the existing equations of state (EOS).

Generation of Free Radicals in Lipid Emulsion Used in Parenteral Nutrition

Lipid emulsions used in parenteral nutrition are prone to peroxidation that may be an important feature of oxygen-associated tissue damage. Incubation of lipid emulsion [Intralipid (IL)] with H2O2 and FeCl2 increased lipid peroxidation, measurable as increased production of pentane, from 0.39 +/- 0.33 to 0.99 +/- 0.18 microM (p less than 0.0001). Malondialdehyde was increased from 0.010 +/- 0.005 mM to 0.380 +/- 0.025 mM (p less than 0.001). Superoxide dismutase and catalase (each 100 U/mL) or vitamin C (10 mM) inhibited pentane and malondialdehyde production (p less than 0.0001). Incubation of human erythrocytes in the presence of FeCl2 caused 11.0 +/- 3.2% hemolysis (control 0.95 +/- 0.14%). Addition of 0.44% IL increased hemolysis to 66.5 +/- 3.4%, whereas further addition of vitamin E or C significantly inhibited hemolysis to 16.4 +/- 8.1 and 38.9 +/- 7.1%, respectively (p less than 0.0001). IL was administered i.v. to eight preterm infants. It increased 3- to 28-fold (p less than 0.001) the amount of pentane in expired breath. Partly, this increase was due to pentane dissolved in IL as a result of lipid peroxidation during storage. After discontinuing IL infusion, the elimination of pentane was nonexponential, consisting of a rapid and a slow component. According to our results, IL undergoes peroxidation causing free-radical-dependent damage to human cells. We propose that the adverse effects of parenteral IL are partially caused by free oxygen radicals generated by lipid peroxidation.

The effect of sulphur compounds on hydrodenitrogenation of nitrogen compounds on a nickel-tungsten catalyst

Hydrodenitrogenation of pyridine on a sulphided NiO-WO3/Al2O3 catalyst has been studied in the presence of ethanethiol, propanethiol, thiophene and hydrogen sulphide and the amount of pentane, 1-methylpiperidine, 1-ethylpiperidine and piperidine has been determined. It was found that in the presence of all the sulphur compounds but hydrogen sulphide, the conversion of pyridine was lower than in their absence. The presence of hydrogen sulphide increased pyridine conversion.

Addition of n-pentane to slowly reacting mixtures of hydrogen + oxygen at 480 °C

A detailed analysis has been made of the products formed when small amounts of pentane are added to slowly reacting mixtures of H2+ O2 at 480 °C. Use of the rate constants for attack of H, O, OH and HO2 at specific C—H bonds in pentane enables the proportion of pent-1-yl, pent-2-yl and pent-3-yl radicals to be calculated for all mixtures studied. Use of a wide range of H2 and, particularly, of O2(8–355 Torr) pressures makes it possible to confirm suggested mechanisms for the oxidation of each of the three species of pentyl radical. Rate constants have been obtained for a large number of the elementary reactions involved, almost all of which have not been determined previously. The values of the rate constants form a very consistent pattern with those determined from studies with the C2–C4 alkanes and neopentane as additive.