Design and economic analysis of natural gas hydrate regasification process combined with LNG receiving terminal

Abstract

In this study, natural gas hydrate (NGH) regasification process combined with liquefied natural gas (LNG) receiving terminal is designed. Since NGH contains excess water, the process needs a dehydration step to avoid reproduction of hydrate in the pipelines. As a method for dehydrating NGH, the enhanced dew point shift is chosen, and the last water specification is achieved by mixing with a LNG stream, which contains negligible water. To cool down the compressed NGH stream, the cryogenic energy of LNG receiving terminal is used. After designing the NGH regasification process, the economic analysis is carried out according to the shipping distance, type of refrigerant, capacity of carrier, and mixing ratio of NGH over LNG. Then, comparison between the conventional LNG chain to the proposed chain that utilizes both LNG and NGH is made. When the quantity of regasified natural gas is fixed at 3.7 million metric tons per year (MTPA), the proposed chain is able to reduce the total chain cost by up to 10.6% compared to the conventional LNG chain in the case of natural gas (NG) delivery to South Korea. Lastly, the risk on investment with respect to the NG liquefaction cost is conducted. According to this, as the shipping distance increases, the risk of the proposed chain decreases. (C) 2016 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.