A Tank for Transporting Liquefied Natural Gas

Abstract

A solution to the problem of liquefied natural gas delivery to consumers far away from the base gas supply stations is offered. The new method can be applied to significantly improve engineering services and broaden functional potentials of LNG plants with no additional energy consumption. A distinctive feature of the proposed method of LNG transportation to consumers is that the useful refrigerating potential of the LNG is utilized to precool the natural gas before liquefaction, which allows use of lower-power compressors.Natural gas is an efficient and a precious energy resource. A constraint to delivery of natural gas to some regions of Russia is the problem of transportation. Creation of a system of natural gas transportation in liquefied state as an alternative version to pipelines is therefore fully justified. Today, there are a reliable base and technical prerequisites in Russia for widespread utilization of liquefied natural gas (LNG) in the national economy.Currently, in some countries, the cold of the LNG is utilized in ammonia production plants, desalination of sea water, foodstuff preservation, processing utility wastes, dry ice production, etc.[1]. Producing cold is a power-intensive process, so power saving in producing and transporting liquefied gas is an urgent task. Natural gas is liquefied by cooling it to saturation temperature, which corresponds to the pressure of the LNG produced. One of the deficiencies of the known plants and methods for LNG production employed in our country is uneven distribution of the gas stream because in the precooling loop natural gas condenses partially. For more even distribution of the gas stream in the liquefaction loops, additional equipment is needed, which leads to increased pressure gradient in the system and reduced liquefaction efficiency.The proposed idea consists in returning the cold generated in the LNG regasification process back to the LNG plant and utilizing it to precool the natural gas in the liquefaction cycle (Fig. 1).Method of LNG production and transportation to consumers. Pipeline natural gas is cleaned, dried (i.e., pretreated), cooled in heat exchanger, compressed at compressor station, and sent to liquefying block. The liquefied natural gas is delivered for storing in LNG storage tanks (e.g., of trademark BSKhP), from which it is pumped out by a cryogenic pump (e.g., of trademark NkpM) into the space of the cryogenic tank Dewar flask.The cryogenic tank provides for the main casing (inside which the flask is put for gas shipment) and an additional casing (installed and secured between the main casing and the flask). The space between the main and additional casings is filled with the cold carrier and the space between the additional casing and the flask, with a highly efficient insulating material [2,3]. The cryogenic tank is provided with fittings, devices for measuring level, pressure, and temperature, safety devices for protection from excess operating pressure (in the inner flask, heat-insulating chamber, and pipelines). The LNG temperat...

Determination of the Optimal LNG Plant Location in the Gas Supply Area Plan

“…Economic efficiency estimation liquefied natural gas usage shows that this energy carrier allows to provide consumers safe and competitive fuel in those regions of the country where construction of gas pipelines is economically inexpedient [8].…”

“…Questions related to the optimal installation location for the liquefaction of natural gas, are relevant, but little has been worked out theoretically and practically. For optimal functioning of the LNG complex it is necessary to establish a clear interaction between its main components [1,8]. The liquefaction complex is an important and capital-intensive step in the natural gas transmission chain as a reference point for autonomous fuel supply systems.…”

“…This problem is especially acute in the eastern regions of the Russian Federation [7]. For remote settlements, where the main gas pipelines are practically inaccessible, and the construction of gas distribution pipelines is economically inefficient, the use of liquefied natural gas can become a viable alternative to laying gas pipelines [8].…”

“…Liquefaction plant is an important link in the technological chain of liquefied natural gas delivery to fuel consumers [5,8]. In this regard, optimization of plant parameters can significantly improve the overall technical and economic performance of the autonomous gas supply system.…”

“…The main advantages of small plants for the liquefied natural gas production include: significant space savings required for the construction of the plant; decrease in capital investments about 40%, and operational -about 20%; use of simpler technologies; reliability and ease of operation [8].…”