A rational thermodynamic use of liquefied natural gas in a waste incinerator plant

Following the increasing global request for natural gas, the regasification of Liquefied Natural Gas (LNG) is becoming a more widespread process. Liquefied natural gas is transported by gas tankers at a temperature of around 113K at atmospheric pressure. The successive process of regasification, necessary to inlet the gas in the pipeline network, makes it possible to use the LNG exergy for various applications, particularly for the production of electrical energy. In this work, the possibility of capturing the thermal energy released during regasification with an ammonia closed Rankine cycle and an LNG open Rankine cycle, associated to a steam closed Rankine cycle of waste incinerator, is investigated. The three consecutive cycles consent an increase in both the electrical production and thermodynamic efficiency, whilst carrying out regasification of the LNG with consequent environmental benefits. The set of three cycles constitutes a new plant configuration whose functioning does not constrain the processes of the regasification terminal. - Highlights: ► Performances improvement in a waste incinerator plant to produce electric energy. ► Better exploitation of LNG as cold thermodynamic source with ammonia Rankine cycle. ► Thermodynamic analysis of three cycles in sequence and regasification of LNG. ► Growth of specific work and thermodynamic efficiency and parametric analysis. ► Reduction of seawater flow rate and CO2 emissions in regasification process.