Liquefied natural gas as a backup fuel for TPP

Abstract

Major trends in the development of the gas industry point to a large-scale expansion of the liquefied natural gas (LNG) market, which continues to be a fast-growing segment compared to other energy sources. The national policy of the Russian Federation is aimed at developing the infrastructure of LNG complexes. This article analyses the world experience in the use of LNG complexes in gas consumption peak damping installations, which meet the conditions of LNG use as a backup fuel by PJSC Mosenergo branches (low-tonnage production combined with a large volume of LNG storage). It is shown that, in terms of the conditions of production and use of LNG at power plants, the most suitable are installations with 90–100% liquefaction of the incoming gas flow with an external refrigerating circuit using a mixed refrigerant or nitrogen, which provide the composition of regasified LNG almost identical to the composition of the source gas. The authors have formulated requirements for the development of energy-efficient LNG complexes at PJSC Mosenergo branches, including ensuring cycle energy consumption by expanding the network gas in the expander with utilization of refrigerating capacity in the liquefaction cycle, as well as cooling the compressed coolant of the refrigerating circuit by gas flows supplied further for combustion. The technological features of implementation of the LNG complex for production, storage and regasification of LNG as a reserve fuel for TPPs are reviewed. The study has shown that the most suitable power plant for the introduction of an LPG complex is TPP-22, for which a new fuel oil facility is being designed. Despite the current practice of using fuel oil and diesel fuel as backup fuels, LNG can have a competitive advantage through the use of secondary energy resources of TPPs.