Autonomous gasification using liquefied natural gas (LNG) is rather new technology in Russia. However it has wide prospects of application especially in areas remote from cross-country gas pipelines. Acting in the scope of Gazprom OJSC Remote Regions Gasification Program adopted in 2011 Cryogastech LLC has performed designing of the Natural Gas Liquefaction Plant (NGLP) being built in Karagay urban settlement, the Perm Territory . The Liquefaction Plant is a part of the unified system for liquefaction, storage, transportation and regasification of LNG in the Perm Territory.
A reliable and proven liquefaction method using nitrogen pressure-reducing cooling cycle with 100 % liquefaction ratio was chosen at designing the NGLP. The technology used in the plant operations includes the following main processes:
- condensed moisture separation and particulate matter filtration;
- adsorption and desorption of residual moister on molecular sieves;
- heating and cooling of gas in plate heat exchangers;
- low-temperature natural gas condensation;
- LNG production;
- LNG accumulation in semi-isothermal tanks;
- LNG distribution by pump.
All primary processes of the Plant are regulated by Automated Process Control System (APCS). Number of manual operations is minimized. The Plant is equipped with fire-fighting and air pollution control systems signal of which can shut it down automatically.
Auxiliary materials in the Plant are either used in closed loop and not consumed (liquid coolant, Freon) or consumed but can be produced by the Plant systems (nitrogen, electric power). Therefore the Plant requires availability of natural gas only. Such self-sufficiency is very important for gas supply to remote regions of Russia.
Liquefaction is just one of stages in the process of LNG use for gasification of the Perm Territory districts. LNG regasification i. e. liquid evaporation and heating of formed vapors to required temperature is performed before supplying gas to a consumer. For LNG regasification Cryogastech LLC has carried out designing of technology for three "LNG Intake, Storage and Regasification Systems" (LNG ISRS) being constructed in Ilyinsk , Karagay and Siva districts of the Perm Territory.
LNG will be regasified in LNG ISRS using atmospheric vaporizers. Such vaporizers have simple design and do not require energy input for regasification. Two parallel vaporizing lines being switched with frosting are used to prevent breaks in LNG ISRS operation connected with evaporator freezing during operation. At low ambient temperature gas at evaporator outlet is heated in electric heaters.
LNG ISRS is designed by Cryogastech LLC under unified scheme and that allows simplifying its operation and maintenance. The technology used in the plant operations includes the following processes:
- LNG accumulation in cryogenic tanks;
- LNG isothermal storage and its supply to vaporizers;
- evaporation (boiling) and heating in atmospheric vaporizers by means of supplying atmospheric air heat to LNG;
- gas heating in electric heaters.
LNG ISRS is automated to the maximum similar to NGLP. Actually operator assistance is required in the course of LNG tank filling only. Equipment parameters can be monitored both locally and remotely. It allows enhancing safety of operation and simplifying provision of timely LNG supplies. Natural gas meeting GOST 5542-87 and fed to medium pressure pipeline for distribution to customers is at the production zone outlet.
1) Natural Gas Liquefaction Plant (NGLP) in Karagay Settlement – [Source]. URL: http://криогазтех.рф/reference/proizvodstvo-spg/56/,
2) LNG Storage System in Ilyinskiy District, the Perm Territory – [Source]. URL: http://криогазтех.рф/reference/khranenie-spg/101/.