Transporting Pipeline Research Articles

Heat transfer characteristics of oil-water two-phase in pipeline transportation during shutdown

Gathering and transportation pipelines often appear shutdown condition due to damage, leakage, and other reasons. The reasonable maintenance time should be controlled by closely combined with the change law of the oil-water temperature in the pipeline. This paper established a multi-field coupling 3-D heat transfer mathematical model of the oil-water pipeline environment based on the two-phase shutdown pipeline as the research object. According to the changing law of the oil-water temperature field and flow field under a typical pipe diameter, the evolution behavior of the gelation layer in the pipe and the transformation process of heat transfer mode were analyzed, and the heat transfer characteristics between oil-water phase and its interface in the pipe were defined. With the liquid phase ratio of the oil phase changing the rule, reasonable maintenance time suggestions were given for gathering and transporting pipelines with different water content.

Full-scale tests of transporting pipeline sections : A review and consequences to our investigations

Hydrocarbon transport pipelines' safe operation is an economic and environmental interest. These pipelines are typically designed for static loads, but during their long-time operation - due to pressure changes and environmental impacts - they are also subject to cyclical loads. The individual pipe sections are connected by girth welds, which represent potential sources of hazards in terms of damage. In order to assess the reliability of girth welds, full-scale tests are carried out under simple and complex loads. The purpose of this article is twofold. On the one hand, summarize the full-scale tests on transmission pipelines, with special attention to the tests on girth welds; on the other hand, based on this, draw conclusions for the design and implementation of our own full-scale tests.

Functioning analysis of cathode protection of pipelines for transporting of natural gas through fuzzy logic

The cathodic protection is used to prevent the oc-currence of accidental damages, leaks, generated by the corrosion of metallic structure of tubular material of trans-porting pipelines. Following the proper functioning of the cathodic protection system is made by monitorize of the main parameters: electrical potential pipeline-ground, in-jection parameters (continuous voltage, continuous cur-rent), respectively by measurement of insulating resistance of pipeline. In the case of monitoring of parameters by SCADA, it is constate the fact that are reduce the acciden-tal gases leakeges, generated by corrosion avoid the impact which is produced by the evacuation of hydrocarbons on the envirnment. In this paper is presented an analysis method regarding the functioning of the cathodic protection, the DCVG method coloborated with a fuzzy analysis method, trough which are simultanely operated either the numerical dates, and lexical arguments, prior to locate, in the field, more precisely of the damage. DOI: http://dx.doi.org/10.5755/j01.mech.20.5.6144

STUDY ON FLUIDITY CHARACTERISTICS OF WATER SLUG FLOW CAUSED BY COMPRESSED AIR IN LONG HORIZONTAL PIPELINE

Recently, the long-distance mud transport pipeline systems using a compressed air are utilizing in the field of marine construction works and coastal zone developments. This system is very useful for high density mud transport. However, previous studies of air-liquid two-phase flow have mainly focused on the flow deformation phenomena in short-distance pipeline. The purpose of this study was to clarify the mechanism of mud transporting pipeline system using a compressed air in the experimentally. This papers describe about moving velocity, pressure gradient, pressure fluctuations and passage period of slug flow in long pipeline. As the result of experiment, itwas to clarify that the rate of increase on slug velocity is remarkable at the end of pipeline and it was shown that the passage period of slug flow in long pipeline was controlled by quantity of liquid.