Liquids pipelines

It is often a requirement for industrial fabrications that once complete they are dried. The reason for this are as diverse as the applications it is used for but typical applications for drying include electrieal transformers, gas and liquid pipelines, thermal insulation and cryogenic applications. Drying through the application of vacuum allied with energy input is often the only solution. Drying with vacuum is... 

Wilson, K. C. Hydrotransporl 4 (BHRA Fluid Engineering, Banff. Alberta, Canada) (May 1976) ALL A unified physically-based analysis of solid-liquid pipeline flow. 

EDM Services Inc., Hazardous Liquid Pipeline Risk Assessment. California State Fire Marshal, Sacramento, CA, 1993. 

Radon s main use is as a short-lived source of radioactivity for medical purposes. It is collected from the decay of radium as a gas and sealed in small glass capsules that are then inserted at the site of the cancer. It is also used to trace leaks in gas and liquid pipelines and to measure their rate of flow. The rate at which radon gas escapes from the Earth is one measurement that helps scientists predict earthquakes. 

The main technical difference between liquid and gas pipeline transport is the compressibility of the fluid being moved and the use of pumps, rather than compressors, to supply the pressure needed for transport. The primary use for liquids pipelines is the transport of crude oil and petroleum products. 

At the beginning of 1992, the largest liquids pipelines in the United States, based on pipeline length, were Amoco Pipeline Co., 19,096 km Mobil Pipe Line Co., 15,026 km Exxon Pipeline Co., 14,983 km and Conoco Pipe Line Co., 12,980 km. Distances do not include 1316 km of the Trans-Alaska Pipeline with multiple ownership. In both 1991 and 1992, the product pipeline company with the most product deliveries was Colonial Pipeline with 104,990,000 m3, more than double the amount delivered by Santa Fe Pacific Pipelines, Inc. The top pipeline in terms of cmde oil deliveries was the Alyeska Pipeline Service Co., operator of the Trans-Alaska Pipeline System, with movement of 105,735,000 m3 (3). 

Pipeline technology involves design, construction, maintenance (qv), and operation. Although certain aspects of the technology differ under different climatic conditions, whether above or below ground or under water, etc, the basic steps are the same for liquids pipelines as for gas pipelines. 

U.S. Department of Transportation (DOT) statistics on liquids pipelines operated under the Code of Federal Regulations (49) indicate that corrosion was the second largest contributor to accidents and failures for the period from 1982 to 1991. These statistics covered an average of 344,575 km of liquids pipelines and were derived from required reports to DOT on all pipeline accidents involving loss of at least 7.95 m3 of liquid, death or bodily harm to any person, fire or explosion, loss of at least 0.8 m3 of highly volatile liquid, or property damage of 5000 or more (50). Similar results were also reported for 1991 in the 1992 DOT/OPS report on both oil and gas pipeline incidents 62 out of 210 oil pipeline incidents were due to corrosion, of which 74% were due to external corrosion (43). For gas pipelines, 16 of all 71 reported incidents were due to corrosion, of which 63% were reported as due to internal corrosion however, internal corrosion of gas pipelines is likely only if C02 and H20 and/or H2S are present, as with unprocessed gas in gathering lines. 

Between 1985 and 1991,1726 natural gas pipeline ruptures andleakages were reported in the United States. These incidents resulted in 634 injuries and 131 fatalities. Third-party damage was the most common cause of these incidents, followed by corrosion. The GAO believes that the corrosion-related incidents can be reduced with the use of smart pigs (46). U.S. DOT 1992 accident statistics showed that 52.5% of U.S. oil spills involving loss of at least 1590 m3 came from pipeline accidents, comparable to the worldwide statistic of 51.5%. The U.S. DOT regulated 344,575 km of liquids pipelines during the 10-yr study period and received reports on 1901 accidents during that time thus the number of failures per year per 1000 miles was 0.888, of which 27% was due to corrosion and 31% to outside forces (48). 

The most reliable methods for fully developed gas/liquid flows use mechanistic models to predict flow pattern, and use different pressure drop and void fraction estimation procedures for each flow pattern. Such methods are too lengthy to include here, and are well suited to incorporation into computer programs commercial codes for gas/liquid pipeline flows are available. Some key references for mechanistic methods for flow pattern transitions and flow regime-specific pressure drop and void fraction methods include Taitel and Dukler (AIChEJ., 22,47-55 [1976]), Barnea, et al. (Int. J. Multiphase Flow, 6, 217-225 [1980]), Barnea (Int. J. Multiphase Flow, 12, 733-744 [1986]), Taitel, Barnea, and Dukler (AIChE J., 26, 345-354 [1980]), Wallis (One-dimensional Two-phase Flow, McGraw-Hill, New York, 1969), and Dukler and Hubbard (Ind. Eng. Chem. Fun-dam., 14, 337-347 [1975]). For preliminary or approximate calculations, flow pattern maps and flow regime-independent empirical correlations, are simpler and faster to use. Such methods for horizontal and vertical flows are provided in the following. 

Gibson, N., Effect of electrification in ball valves on ignition risk in liquid pipeline systems, J. Electrostatics 1, 339-350, 1975. 

High energy content, low vapor pressure (200 psi), and liquid state at ambient temperatures favors low-cost liquid pipeline transportation vs. high-pressure compressed gas—1000+ psig if methane conversion is done near the production site. 

What if high pressure flammable, corrosive or toxic gases leak into a liquid pipeline ... 

The purpose of formal pipeline integrity management is to better manage safety in HCAs. There are several types of HCAs and definitions differ between those designated for gas and liquid pipelines. An example for gas pipelines is ... 

Pipeline safety pipeline integrity management in high consequence areas (hazardous liquid pipeline operators with 500 or more miles of pipeline). In Federal Register, 49 CFR Part 195 Department of Transportation, Research, and Special Projects Administration Vol. 65 (232) 75, 378, Dec 1, 2000. 

American Petroleum Institute. Assurance of Hazardous Liquid Pipeline System Integrity, 1st Ed. American Petroleum Institute Washington, DC, Aug 1996 API RP 1129. 

Rgura 8.1 Control valve installed in a liquid pipeline. 

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