A Multiscale-System Analysis of the Techno-Economic and Environmental Aspects of Shale and Natural Gas Monetization Pathways

Abstract

Within the context of increasing global efforts to minimize CO₂ emissions into the atmosphere, attention has been directed toward finding cleaner means of energy generation and feedstock production to sustain global demands for energy and raw materials. As a result, shale/natural gas emerged as a transition fuel toward achieving net-zero emission targets. This work aims to synthesize novel tools to effectively harness the benefits of shale/natural gas monetization pathways. The research develops approaches to address the following problems: (1) development of a systematic selection methodology for the available methane reforming technologies, (2) development of shortcut cost correlations and carbon-footprint estimation of shale/natural gas reforming units, and (3) an overall collaborative approach between process systems engineering and catalysis to accelerate the development of chemical processes.

In light of the first problem, the different pathways for methane reforming processes were studied and their unique attributes considered. A selection methodology is presented to identify the most suitable reforming pathway based on the downstream application of interest. The technologies were characterized based on eight key process metrics: (i) H₂/CO ratio, (ii) capacity range, (iii) capital intensity, (iv) operating pressure and temperature, (v) ability to tune H₂/CO ratio, (vi) steam requirements, (vii) O₂ requirements, and (viii) CO₂ intensity.

To address the second problem, over 350 plants worldwide that utilize a reforming unit were surveyed. Of these, 78 were considered for further analysis. The types of plants considered included Gas-to-Liquids (GTL), methanol, and ammonia. Rigorous analyses were carried out based on the plants’ reported capital costs to develop an order-of-magnitude (initial estimate) capital cost correlation. A second correlation to estimate the operating costs of the methane reforming unit was developed based on the feed and energy requirements of the primary reforming reactions. A similar approach was applied for the development of the CO₂ intensity correlation.

Finally, a collaborative methodology between process systems engineering and catalysis is introduced. The methodology aims to accelerate the development of chemical processes by incorporating research efforts at an early stage of technology development. A case study of a methane-to-methanol process is presented to illustrate the use of the proposed methodology.