Carbon capture and utilization (CCU) has emerged in recent years as a promising decarbonization solution for hard-to-abate industries. Compared to carbon capture and storage (CCS), CCU aims not for the storage of carbon dioxide (CO₂) but for its use in the production of synthetic fuels, such as synthetic methanol (MeOH). Synthetic MeOH is produced through CO₂ hydrogenation, utilizing green hydrogen (H₂). Efficient use of CO₂ and H₂ feedstocks is essential to maximize the carbon reduction potential and energy efficiency of the process. This study performed an optimization analysis on a small-scale, containerized, and portable CO₂ hydrogenation unit with a 5 kg MeOH/h production capacity goal, focusing on carbon conversion efficiency (CCE), MeOH yield, H₂ consumption, and MeOH purity. The analysis was conducted using Aspen Plus V12. A single-pass model was used first to evaluate an initial reactor design. The reactor was then re-designed according to the results of the gas hourly space velocity (GHSV). The model was then expanded to include a recycling loop and the final reactor design was validated, aiming to maximize overall efficiency. The effects of the operational parameters including the reactor inlet temperature, reactor pressure, thermal fluid temperature, and condensation temperature were examined. The model was then further expanded to include the MeOH distillation process, and the effect of the distillation temperature was examined. The final product of the analysis was a fully-defined and optimized unit, achieving an 87.97% CCE and an 84.99% MeOH yield, consuming 1.11 kg H₂/h for the production of 5.01 kg MeOH/h of 99.86 wt% purity. This study can provide valuable information and guidelines for designing small-scale, containerized, and portable CO₂ hydrogenation units, which can serve as alternative solutions to address issues of H₂ production and transportation related to large-scale installations.

Decarbonization of hard-to-abate industrial sectors, namely the extractive industries, has become an imperative, and thus, processes such as carbon capture and utilization (CCU) have been explored thoroughly and seem to be a promising solution. Carbon dioxide (CO₂) catalytic hydrogenation employing green hydrogen (H₂) to produce synthetic methanol (MeOH) aims to utilize industrial-captured carbon. A thermodynamic and kinetic analysis of a pilot scale methanol synthesis reactor was conducted by modeling the process using Aspen Plus V12 software. The methanol synthesis model consists mainly of a multi-tubular packed-bed reactor with a thermal oil heat recovery system, a product separator, and an internal recycle loop for optimal efficiency. The reactor has a 5 kg h⁻¹ methanol production capacity, and its heat recovery system achieves an overall heat reduction of 64.1% and can retrieve 1.293 kWh per kg of methanol produced. The overall carbon conversion achieved is 80.6%. Valuable information concerning the design and profile of the reactor is provided in this study.