Improvement of the LNG (liquid natural gas) regasification efficiency by utilizing the cold exergy with a coupled absorption – ORC (organic Rankine cycle)

• Improvement of absorption method for LNG cold exergy utilization is proposed.
• The use of ethane–krypton pair for the absorption system is analyzed.
• Significant improvement of exergetic efficiency and power output achieved.
• Comparison with other methods shows large benefits of the proposed solution.

Regasification is the process of evaporating and compressing LNG (liquid natural gas) so that the product meets the parameters of a local distribution network. During this process large amounts of potentially useful exergy are destroyed. There were several proposals of using this potential in practice. In this paper the methods for electric energy production using cold exergy from a LNG stream are investigated. The new improvement is proposed for an absorption power cycle by coupling it with an organic Rankine cycle. The new components for working fluid are evaluated. The proposed solution is compared to existing ones and analyzed using a computer model. A significant increase of exergetic efficiency and power output is observed when compared to previous solutions.