LNG gasification has been considered as a method of alternative gas supply to facilities distant from cross-country gas pipelines for long enough. In 2012-13 OJSC Gazprom Gazenergoset jointly with the Perm Territory Administration proceeded with implementation of this idea in practice. More than 15-year positive experience in LNG gasification of facilities located in the Leningrad region played not unimportant part in taking the positive decision.
Construction of the Natural Gas Liquefaction Plant (NGLP) in Karagay urban settlement (the Perm Territory, Russia), LNG production and its further supply to consumers allows switching the existing coal, fuel oil and diesel municipal boiler houses to natural gas as well as providing natural gas supply for needs of the public thus reducing environmental impact as well as raising the living standards of people living in these settlements.
The most reliable and proven liquefaction method representing 100 % gas liquefaction using nitrogen cooling cycle is used at designing the Liquefaction Plant. 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;
As well as auxiliary processes:
- nitrogen adiabatic expansion in turbine expanders;
- nitrogen compression in compressor unit;
- nitrogen production in air separation plant;
- electric power generation in gas reciprocating power plant (GRPP).
The accepted process solutions have been designed on the basis of:
- positive data of continuous operation of similar LNG production plants abroad;
- cryogenic equipment and valves operating experience;
- developed methods of computation of phase equilibrium and thermodynamic properties, processes, compression, expansion, boiling and heat exchange;
- developed process simulation system.
The used process of LNG production facility process equipment operation is automated. All primary processes including switching of operation and regeneration of dehydration plant adsorbers, operation of natural-gas fueled reciprocating-engine power plant, nitrogen compressor, temperature maintenance in LNG liquefaction unit (Coldbox), maintenance of produced LNG pressure, filling of LNG accumulation process tanks and switching of LNG supply from filled tank to an empty one are regulated in automatic mode.
Connection of transportation tank to LNG filling unit, opening of valves on transportation tank and filling unit, preparation, cooling down and start of LNG pump are performed in manual mode. Filling process is controlled by an operator using commercial motor-truck scales and readings of level gages on transportation tank and process tank with LNG.
Air pollution is monitored at the site and signals on two levels of air pollution are transmitted to Air Pollution Monitoring System and APCS in automatic mode. In automatic mode flame sensors control fire condition at the site with equipment. A signal is sent to protective fire-fighting system in case of fire.
Automatic Process Control System (APCS) has direct communication with air-pollution and fire-fighting systems. In automatic mode it shuts down operation of Natural Gas Liquefaction Plant, cuts off every process tank and unit from LNG supply, shuts off natural gas supply at the inlet, stops LNG pump operation (if it runs) and closes LNG supply motor operated valve if required.
Sprinkling of LNG process tanks is activated by command from fire-fighting system and signal is sent to fire-fighting service point. Loudspeaker notification of personnel present at NGLP site is carried out simultaneously.
The created Natural Gas Liquefaction Plant is designed as a fully-autonomous unit and natural gas only is required for its operation. Such solution allows installing it almost in any area and that is very important at gas supply to remote areas of Russia.Back to the section