Comparison of Various Technological Options in a Smr-Hydrogen Plant in Refineries for Supplying CO2 Feedstock to Combined Reforming and Dry Reforming of Methane Based CO2 Conversion Processes

Combined reforming (CR) and dry reforming (DR) of methane are two of the most promising CO₂ conversion reactions for utilizing concentrated CO₂ as a feedstock to produce syngas, which is used in various applications like liquid fuel synthesis.[1,2] In order to make these conversion processes more economically attractive, it is important to procure CO₂ feed as cheaply as possible. Steam methane reforming (SMR) based hydrogen pl ant in typical refineries is a suitable CO₂ emission source to target for this because there are process streams containing CO₂ at high partial pressure, giving potentials for an acceptably low CO₂ avoidance cost ($/ton of CO₂).[3] The aim of this study is to compare various processing options for removing CO₂ in a SMR-H₂ plant and supplying it to the two CO₂ conversion processes, employing the combined reforming and dry reforming of methane, respectively. As the technological candidates, three CO₂ capture technologies applied to the H₂ purification unit upstream are considered: physical absorption (1-stage Selexol), chemical absorption (activated MDEA), and adsorption (Vacuum Swing Adsorption). In addition, the applicability of directly feeding the a CO₂ containing output stream of the H₂ purification into the CO₂ conversion processes is examined, an option that does not require any CO₂ capture facility. Methanol and long-chain hydrocarbons are selected as final products of the CR based and the DR based CO₂ conversion processes respectively because they guarantee the suitable syngas conditions for synthesizing the targeted products. Mass and energy balance information of each process is obtained by a commercial process simulator Aspen plus¢ç. To analyze the economic feasibility of each technological option, operating and capital costs are evaluated.

Figure 1. Four different strategies (three CO₂ capture options & process stream direct use) for integrating the H₂ plant with CO₂ conversion processes

Reference

[1] Olah, G. A.; Goeppert, A.; Prakash, G. S., Beyond oil and gas: the methanol economy. John Wiley & Sons: 2009.

[2] Gadalla, A. M.; Bower, B., The role of catalyst support on the activity of nickel for reforming methane with CO₂. Chemical Engineering Science 1988, 43 (11), 3049-3062

[3] Soltani, R.; Rosen, M. A.; Dincer, I., Assessment of CO₂ capture options from various points in steam methane reforming for hydrogen production. International Journal of Hydrogen Energy 2014, 39 (35), 20266-20275