Supply chain analysis and upgrading of liquefied natural gas (LNG) to meet Finnish gas market specifications

Abstract

Liquefied natural gas (LNG) presents clean, cost-effective solution for transportation/ shipping of natural gas from remote reservoirs to consumer market. Until recently, the limits of natural gas properties, acceptable to LNG importers, had been lenient, as it was generally used for power production. However, new markets, as they use LNG to supplement their current supplies, demand an LNG with characteristics/ quality compatible to their existing pipeline grid and clientele specifications. This raises natural gas harmonization, interoperability and interchangeability issues in potential LNG importers, such as Finland which is wholly reliant on single natural gas source from Russia. Rising environmental concerns, stiffening emission regulations and energy security drive Finland to import LNG.

This thesis is aimed at identifying the world LNG sources suitable for import to Finnish market based on specifications required by natural gas applications in Finland. The thesis also studies the LNG value chain in general and the LNG quality modification at import terminal/ regasification plant.

Production, liquefaction, storage, transportation, and regasification are core components of LNG value chain besides numerous minor constituents including LNG liquid fuel engines. Finnish natural gas market is divided into broad segments of traffic, off-grid industry and existing gas grid users. Specification-data of all three designated sectors was collected from the manufacturers and industry. By considering three interchangeability parameters of natural gas: methane number, Wobbe index (lower), and lower heating value, this data was mapped on charts to determine the requirement of each sector and finally the common demand band (common window) of all the sectors. Similarly, the data of 27 available LNG sources and 3 European LNG re-export terminals was gathered and graphically analyzed. A preliminary simulation of 3 alternative processes, by means of Aspen HYSYS software, and their subsequent comparison resulted in selection of LPG Extraction as the most feasible LNG de-richment technique employed at a receiving terminal LNG re-vapourization plant.

As per the current Finnish market requirement and grid conditions, out of 27 global LNG sources, the number of feasible sources remains 3; however, it could be increased to 7 by compromising land traffic sector methane number demand, and to 11 if the upper bounds for heating value are relaxed up to +3%. LNG from rest of the producers can be viable with additional processing at the targeted market in Finland.