Last number of the PLYN journal – 4/2017


  • The American LNG Trade
  • Nord Stream 2 and the USA’s New Sanctions against Natural Gas from Russia
  • Difficulties of the Turkmen Gas Industry: The End Nowhere within Sight
  • The Future of Supply to Europe, A Study
  • Economics of Heat Production in Certain Plants
  • Ravetti 2
  • The Boiler Subsidies – Evaluation of the First Wave
  • In Brief…
  • Other Periodicals
  • CNG Motoring – New Fuelling Stations


  • CNG Is the Greenest Solution for Transport
  • Josef Kaňa Passes Away
  • Expert Opinions Issued in 2017
  • New CGA Regulations
  • The Board Congratulates


Preventing the Formation of Flammable Hydrocarbon Mixtures through Inerting

Tarig Hussein, Daniel Maxa, Martin Stukbauer, Adam Pařízek, Jan Karl

Summary: irect purging of gas pipelines using air carries an explosiv hazard due to the formation an explosive mixture. The situation get is even more complicated in case of purging a pipeline carrying rich gas due to hydrocarbon condensate separation. Analogically, oil and other petroleum products displacement operations are also challenging as regards safety. The indirect prurging method replaces air with inert gas (typically nitrogen) in order to reduce the explosiv hazard (mandatory in case of pipelines transporting flammable liquids). For this method purpose, CEPS has developed and operates nitrogen units producing a nitrogen inerting mixture with a low content of residual oxygen. These units bring more convenience as regards flexibility, off-road mobility and operating economics compared with conventional liquid nitrogen tank trucks.
For a case of nitrogen inerting of REB crude vapours, the conducted experiments examined the minimum requirement for purging nitrogen purity using a relationship between the MAI parameter and absolute initial pressure ranging between 1 bar and 26 bar (25˚C). The results have confirmed that the nitrogen units operate safely below the limiting residual oxygen content (above the limiting purging nitrogen purity) in the examined range of operating pressures.

Fatigue Strength of Weld Joints on Gas Pipelines

Vladimír Chmelko, Matúš Margetin

Summary: In the actual operation of gas and other pipelines, as well as pressure vessels, there are some sections and junctions where the operating conditions differ from the design conditions. These places usually include booster pump stations and compressor stations where dynamic effects are added to the pressure load on the piping. The most heavily loaded sections are weld joints. Fatigue properties were measured on specimens from the original weld joints on pipelines for two types of material. The multiannual monitoring of pipe loading at a compressor station has made it possible to estimate the real fatigue strength and lifetime of welded pipelines. Some attention is paid to the influence of the orientation of weld joints on their fatigue properties.

A Comparison of Leak Detection Methods

Martin Stýblo, Marko Hauliš, Vít Meistr

Summary: This contribution for the PLYN journal is based on the authors’ paper, under the same heading, for the Safety, Reliability and Operation of the Gas System 2017 conference. It briefly cites statistics of examples, provides an overview and categorisation of detection methods, and summarises general findings for application in the gas industry. The experience with the deployment of the SIMONE software, described in the second part of the contribution, confirms the general findings.

Southern Gas Corridor. Part 1

Matthias Dornfeldt, Igor Korobov

Summary: The Southern Gas Corridor, through which gas produced in the Caspian area is expected to flow, should become an important part of the gas pipelines delivering natural gas to Europe. Two projects, the Nabucco pipeline and the Trans-Caspian Pipeline, through which natural gas from Turkmenistan was planned to flow to Europe, preceded the SGC project. This contribution is dedicated to the reasons why the two pipelines have not materialised in the end.

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