Model-based techno–economic analysis of an integrated synthetic natural gas production system with direct air capture and water electrolysis

Abstract

In this study, a techno-economic analysis is performed for an integrated system of carbon capture and utilization (CCU). The proposed system utilizes CO2 captured by a direct air capture (DAC) process using a metal–organic framework adsorbent. The captured CO2 is converted into a methane product, or synthetic natural gas (SNG), using hydrogen produced by water electrolysis. Rigorous mathematical models are used for the mass and energy balances in the major components of the proposed integrated system, allowing us to estimate the capital and operating costs and energy consumption. A sensitivity analysis is also performed to identify model parameters that significantly affect the SNG cost. Our analysis indicates that the thermal and electrical energies required to produce SNG are 0.409 MJ/Nm3-SNG and 19.6 kWh/Nm3-SNG, respectively, and the cost of SNG is within the range of 1.43–2.60 $/Nm3-SNG.

Keywords

• Carbon capture and utilization
• Direct air capture
• Methanation
• Metal–organic framework
• Power to gas
• Process simulation