Natural gas-crude oil system

The third system is data for a natural gas-crude oil system published by Katz and Hachmuth (118) which is typical of a black oil. The heptanes plus is separated and characterized using a chromatographic analysis for an oil which has a molecular weight and specific gravity similar to the oil used by Katz and Hachmuth. Comparisons between the experimental and predicted K values at three temperatures are shown in Figures 23-25. The agreement is good except for ethane at 200° and 120°F. 

Callaghan and Neustadter [31] have made a study of the foam stabilities of air-crude oil and natural gas-crude oil systems using a variety of light crude oils of viscosities 14 mPa s. This study, at ambient temperature using a sparging method, concerned so-called dead oils from which natural gas had been separated. It also involved a comparison of the foam behavior with critical film rupture thicknesses, bulk phase, and surface shear viscosities together with dilatational surface properties. 

As shown in Figure 10.3 for the natural gas-crude oil system, this study revealed a linear correlation (albeit with a correlation coefficient of only 0.84) between increasing bulk phase shear viscosity and increasing foam stability as indicated by the average foam lifetime, Lp, which is defined as... 

Here is the initial foam height, H, is the foam height at time t, and t is the time for total foam collapse, where aU quantities are relative to those at the situation immediately after sparging has ceased. A similar correlation was observed for the air-crnde oil system—the foam stability of which was lower than for the natural gas-crude oil system. The foam is seeu to be extremely unstable—collapsing with average lifetimes < 45 s even with oils of viscosities up to an order of magnitude higher than that of water. 

More than 2 million miles of pipeline in the United States are used to transport natural gas, crude oil, petroleum products, and other petrochemicals economically and efficiently over long distances. These steel pipelines can be subjected to corrosive conditions both internally (from the aggressive fluids being transported) and externally (from the a ressive soil or subsea environments). The catastrophic failure of an oil or gas pipeline can result in loss of life and environmental disasters. In United States, more incidents/accidents in pipeline systems are due to human intervention, followed by external and internal corrosion.The U.S. Depart-... 

Here S and are defined for an aqueous foaming liquid by Equations 3.5 and 3.6 respectively. However these definitions can be readily generalised for non-aqueous systems by appropriate substitutions of the relevant surface tensions in those equations. This is exemplified for the case of natural gas-crude oil-antifoam systems in Section 10.4.1. 

In this chapter, we first consider the nature of surface activity in gas-hydrocarbon interfaces in general and in gas-crude oil systems in particular. That represents an issue fundamental to understanding the causes of foam formation in gas-oil separators and has relevance for the mode of action of antifoams in that context. In a separate section, we consider the possible causes of foam formation in gas-crude oil systems. There we review the observations of foam behavior in gas-crude oil systems and make the limited comparison with theory which that permits. Finally we consider foam control in gas-oil separators, which usually involves the use of antifoams. Therefore, we describe the design criteria for suitable antifoams and the evidence available concerning their mode of action in a non-aqneons medium such as crude oil. 

The source of these compounds is varied. The butanes are found naturally in crude oils and natural gas. They, plus the olefins, are products of various refinery processes and of olefins plants. They are separated by fractionation, except for butadiene and isobutylene, which are sometimes recovered by extractive distillation. They all vaporize at room temperature, so they are handled in closed, pressurized systems.. 

Katz, D.L., D.J. Vink, and R.A. David Phase Diagram of a Mixture of Natural Gas and Natural Gasoline Near the Critical Conditions, Trans. AIME, vol. 136, p. 106,1940. Katz, D.L. and A. Firoozabadi, Predicting Phase Behavior of Condensate/Crude-Oil Systems Using Methane Interaction Coefficients, J. Pet. Tech., p. 1649, Nov. 1978. 

Finally, we should draw attention to the prevalent use of air-degassed crude oil systems and foam generation by sparging at ambient temperatures and pressures. It is known that solubilities of asphaltenes, resins, PDMS, and PDMS derivatives are likely to be influenced by temperature and dissolution of natural gas. Moreover, sparging represents a poor model for foam generation in gas-oil separators, which involves depressurization and nucleation of bubbles. Use of apparatus designed to replicate the conditions in actual gas-oil separators for basic studies should therefore be encouraged. 

From a practical standpoint, coal, because of its abundance, has received the most attention as a source for synthetic fuels. As early as 1807, a coal-gas system was used to light the streets of London, and until the 1930s, when less expensive and safer natural gas started to flow through newly constructed pipelines, gas piped to homes in the Eastern United States was derived from coal. Kerosene, originally a byproduct from the coking of coal tor metallurgical applications, can be considered the first synthetic lic -uid fuel made in quantity. But once crude oil became cheap and abundant, there was little serious research on synthetic liquid fuels in the industrial world until the Energy Crisis of 1973. The main exceptions to... 

As crude oil reserves dwindle, the marketplace will either transition to the electrifying of the transportation system (electric and fuel-cell vehicles and electric railways), with the electricity being produced by coal, natural gas, nuclear and renewables, or see the development of an industry to produce liquid fuel substitutes from coal, oil shale, and tar sands. It might also turn out to be a combination of both. The transition will vary by nation and will be dictated strongly by the fuels available, the economic and technological efficiencies of competitive systems, the relative environmental impacts of each technology, and the role government takes in the marketplace. 

The majority of today s turbines arc fueled wth natural gas or No. 2 distillate oil. Recently there has been increased interest in the burning of nonstandard liquid fuel oils or applications where fuel treatment is desirable. Gas turbines have been engineered to accommodate a wide spectrum of fuels. Over the years, units have been equipped to burn liquid fuels, including naphtha various grades of distillate, crude oils, and residual oils and blended, coal-derived liquids. Many of these nonstandard fuels require special provisions. For example, light fuels like naphtha require modifications Co the fuel handling system to address high volatility and poor lubricity properties. 

The material in this section is divided into three parts. The first subsection deals with the general characteristics of chemical substances. The second subsection is concerned with the chemistry of petroleum it contains a brief review of the nature, composition, and chemical constituents of crude oil and natural gases. The final subsection touches upon selected topics in physical chemistry, including ideal gas behavior, the phase rule and its applications, physical properties of pure substances, ideal solution behavior in binary and multicomponent systems, standard heats of reaction, and combustion of fuels. Examples are provided to illustrate fundamental ideas and principles. Nevertheless, the reader is urged to refer to the recommended bibliography [47-52] or other standard textbooks to obtain a clearer understanding of the subject material. Topics not covered here owing to limitations of space may be readily found in appropriate technical literature. 

Due to the water requirement of biocatalytic systems, BDS is typically carried out as a two-phase aqueous-oil process. However, increased sulfur removal rates could be accomplished by using an aqueous-alkane solvent catalytic system [46,203,220,255], The BDS catalytic activity depends on both, the biocatalysts and the nature of the feedstock. It can vary from low activity for crude oil to as high as 60% removal for light gas-oil type feedstocks [27,203,256], or 70% for middle distillates, 90% for diesel, 70% for hydrotreated diesel, and 90% for cracked feedstocks [203,256], The viscosity of the crude oil poses mixing issues in the two-phase oil-water systems however, such issues are minimal for distillate feedstocks, such as diesel or gasoline [257]. 

In 1993 Russia had 48,000 kilometers of pipeline carrying crude oil, 15,000 kilometers for petroleum products, and 140,000 kilometers for natural gas. In recent decades, the natural gas lines have expanded at a much faster rate than the crude oil lines. The main natural gas pipeline, one of the Soviet Union s largest international trade projects, connects the natural gas fields of northern Siberia with most of the countries of Western Europe. Completed in 1984, the line passes nearly 4,000 kilometers across the Ural Mountains, the Volga River, and many other natural obstacles to connect Russian lines with the European system. 

SCO SCPC SD SEC SMR SNG SOFC SPE SRES SULEV SUV Synthetic crude oil Super-critical pulverised coal System dynamics US Securities and Exchange Commission Steam methane reformer Synthetic natural gas Solid-oxide fuel cell Society of Petroleum Engineers IPCC Special Report on Emissions Scenarios Super-ultra-low-emission vehicle Sport utility vehicle... 

All of these equations suffer from at least one common deficiency- -they require that the critical properties of all components in the system be defined. This requirement extends to any undefined component (C6+, crude oil, heavy tar fractions, etc.) which may be present in the system. Prediction of the critical properties of these compounds is at best an art. Changing the critical temperature of an undefined fraction present in quantities less than one mol percent by 10°C can change the predicted dew point of a natural gas system by 35 bar. 

We often refer to the solubility of natural gas in crude oil as if we are dealing with a two-component system. Although it is convenient to discuss dissolved gas in this manner, in fact, the gas and oil are both... 

Shah Deniz is an offshore non-associated gas/condensate field, which is being developed primarily to supply natural gas to export markets in Turkey - and associated liquids to international markets via the crude oil pipeline systems. Production will be brought ashore at Sangachal, where a major gas terminal is to be constructed. In November 2002, the agreement was reached with BOTAS, the Turkish state-owned gas company, for the sale of Shah Deniz gas to Turkey with deliveries commencing in August 2006. 

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