Thermodynamic analysis of a new method for producing electrical energy from natural gas hydrates

Abstract

Natural gas hydrates (NGH) is the largest energy reservoir in the globe which consists of natural gas and water in icy form at artic permafrost regions and deep ocean floors but is still undeveloped due to several technical and economic issues. Finding an economic thermal energy resource to make the hydrate dissociated for harvesting is one of the major difficulties for making this technology viable. In light of this issue, a new hybrid process is proposed and thermodynamically analyzed for its viability. In the proposed method, fuel cell system and gas processing system are combined with hydrate harvesting system. Dissociation heat for harvesting natural gas from NGH is supplied using the waste heat from fuel processing and fuel cell systems. In the article, the proposed method is simulated with Aspen Plus.R simulator incorporating mass balance and energy balance equations at every step conforming the validity of the results as well as the system viability under steady state operating conditions. Moreover, the effect of reforming reaction yield is studied and culminated that 85 % yield gives a better system efficiency than the equilibrium conditions to reach the maximum hydrogen production however at a toll of utilizable thermal energy for heating the hydrate sediments. (C) 2020 The Authors. Published by Elsevier Ltd.