Challenges in production and distribution of low-tonnage LNG

Pavel Mikriukov

Research output: ThesisMaster's Thesis

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Abstract

According to the global market analysis, there is an urgent need to switch to green energy, especially in the fuel and energy sector (utilities, production needs, special equipment, trucks, etc.). Therefore, LNG has been gaining popularity among companies in recent years. Small- scale LNG production can cope with most of these needs for example, it does not require much time for construction of the plant, high capital expenditures, large amount of space for construction, etc.). The basic scheme of LNG production is based on the throttle effect in the reduction unit realized by means of a throttle valve, but there are other ways of realizing this effect. The objective of this research work is to optimize and improve a low-tonnage liquefied natural gas plant based on the nitrogen cycle. This is done by selecting the optimum performance of the LNG plant operating modes, as well as analysing the efficiency of the reduction units and proposing possible options for improving the cooling process in it based on promising technologies (turbo expander and supersonic separator). The global market for low-tonnage liquefied natural gas production has revealed that the main factors for the choice of LNG technology are technological efficiency, reliability of design solutions, ease of plant maintenance, modularity and low investment costs. Moreover, the need to minimise operating costs should be considered. As a result of this analysis, a scheme based on an external isolated nitrogen cycle was chosen as the basic one for further study. Based on the analysis of performance indicators of LNG plant operating modes, based on the results of the calculation experiment, it was found that at flow rates above 5,500 Nm3/h, the gas cooling system cannot cope with the load, i.e., it does not work stably and with a large margin of error in the required values. The work assessed the technological efficiency of a number of possible modes of LNG plant control depending on the request of potential customers. It was found that the LNG plant, consisting of 6 lines of 5500 Nm3/h, has the greatest flexibility, which can provide both the minimum possible load of the plant, and the maximum, exceeding the required one by 30%. It has also been observed that turbo expander and supersonic separator have about the same potential. However, these values are within the margin of error. Considering the materials required for the 3S separator, special non-brittle and cold resistant materials will be required. It has also been observed that turbo expander and supersonic separator have about the same potential. However, these values are within the margin of error. Considering the materials required for the 3S separator, special non-brittle and cold resistant materials will be required.
Translated title of the contributionHerausforderungen bei der Produktion und Verteilung von Low-Tonnage-LNG
Original languageEnglish
QualificationDipl.-Ing.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Hofstätter, Herbert, Supervisor (internal)
  • Kolchin, Alexander, Supervisor (external), External person
  • Fazeli Tehrani, Fatemeh, Co-Supervisor (internal)
Award date25 Jun 2021
Publication statusPublished - 2021

Bibliographical note

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Keywords

  • LNG
  • Low-tonnage LNG
  • Trunk gas pipeline
  • Gas
  • Supersonic Separator
  • 3S-separator
  • Throttle
  • Expander
  • turbo expander unit
  • Gas liquefaction
  • Technology comparison

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