Indexed by:期刊论文

Date of Publication:2017-01-15

Journal:CHEMICAL ENGINEERING JOURNAL

Included Journals:SCIE、EI、Scopus

Volume:308

Page Number:40-49

ISSN No.:1385-8947

Key Words:CH4/CO2 replacement; Thermal stimulation; CH4 replacement percentage; CO2 storage efficiency; Energy efficiency

Abstract:The replacement of CH4 by CO2 in methane hydrates is a promising method for simultaneously achieving CO2 storage and CH4 recovery for global warming mitigation and energy production, respectively. However, gas replacement is restricted to the slow diffusion-limited transport of CO2 caused by the formation of a mixed hydrate layer, and little attention has been paid to the storage of CO2. Therefore, this study proposed a combination of CH4/CO2 replacement and thermal stimulation to enhance CH4 recovery and CO2 storage. The effects of the methane hydrate saturation level, replacement zone, and freezing point on the replacement were analyzed. The CH4 replacement percentage and energy efficiency were obtained and compared using the replacement and combined methods. The results suggested that the combined method effectively improved CH4 recovery, with the CH4 replacement percentage exhibiting an upper limit of 64.63%. Moreover, In CH4/CO2 replacement, the total number of moles of CO2 stored is unequal to CH4 recovered, because the replacement is sensitive to the free water in the pores of the hydrate sediments. In addition, the CO2 storage efficiency was first discussed. The results proved that the CH4/CO2 replacement has obvious advantages in CO2 storage, and a maximum CO2 storage efficiency of 96.73% was achieved by combined method. (C) 2016 Elsevier B.V. All rights reserved.