CO₂ Capture in Natural Gas Production by Adsorption Processes for CO₂ Storage, EOR and EGR

Publication Overview

The aim of this work was to evaluate PSA processes for removal of CO₂ from NG at high pressure. For this, the study performed a techno-economic comparison of a PSA with an amine based solvent process and identified candidate materials for the PSA process.

Publication Summary

• An iterative pathway was applied to find a PSA cycle design with maximum CO₂ The final design consists of a 12-column multi-feed cycle with around 85% CO₂ purity and is the first reported design for the separation of CO₂ and CH₄ at a pressure of 70 bar and flowrates of 500 000 Sm³/h.
• The final PSA design has about 50% higher costs of CO₂ removal (including CO₂ conditioning, transport and storage) and NG sweetening than the reference amine process. However, the process is not yet optimised, so there is ample room for improvement.
• Data availability for suitable adsorbent materials is severely limited. This study used a carbon molecular sieve (CMS) and identified other materials worthwhile of further investigation, such as certain zeolites, titanosilicates, metal organic frameworks (MOFs), zeolitic imidazolate frameworks (ZIFs) and honeycomb monoliths.
• A combined approach of material and process optimisation could significantly reduce the cost of the proposed PSA design, potentially even below the cost for the reference case of amine scrubbing.
• Improving the feasibility of the PSA process for CO₂ capture from NG requires more work in several areas. This includes optimisation of the PSA cycle to minimise NG losses, investigation of novel cycle concepts (e.g. hybrid of single and dual PSA), evaluation of advanced adsorption materials and data for suitable adsorbents at high pressure. This is basic research and modelling work that should be taken up by related research groups from academia and industry.