Optimization Approach to Reduction of CO2 Emissions for Syngas Production Involving Dry Reforming

Dry Reforming of Methane (DRM) is a widely studied reaction which uses CO₂ and CH₄ to produce synthesis gas (CO+H₂) with H₂/CO ~ 1. Since the process uses a waste stream (CO₂), this reaction system has received considerable attention from industry and academia like. However, there are still significant challenges in the path of its commercialization. This work addresses the life-cycle analysis viewpoint looking at the overall CO₂ balance of the DRM process¹. All major sources of CO₂ emissions as well as credits are accounted for based on available greenhouse gas emissions database from GREET. The reformer modeling was based on Gibbs Free Energy Minimization Principle². It was found that for the production of high H₂/CO ratio syngas, the DRM process helps in reduction in overall CO₂ emissions and operating costs only when coupled with a post-DRM processing step where the excess CO is removed. Without this additional step (which will add to the capital costs), the DRM process produces a low-quality synthesis gas (H₂/CO ~ 1). This synthesis gas has limited utility and hence the DRM process cannot compete with existing established processes of syngas production like Steam Methane Reforming where H₂/CO ratios are above 3. The estimated reduction in terms of CO₂ emissions on an industrial scale is presented for the DRM coupled with post-CO removal.

 

REFERENCES

(1) Afzal, S.; Sengupta, D.; Sarkar, A.; El-Halwagi, M. M.; Elbashir, N. O. Optimization Approach to the Reduction of CO2 Emissions for Syngas Production Involving Dry Reforming. ACS Sustain. Chem. Eng. 2018, 6, 7532−7544.

(2) Noureldin, M. M. B.; Elbashir, N. O.; El-Halwagi, M. M. Optimization and Selection of Reforming Approaches for Syngas Generation from Natural/Shale Gas. Ind. Eng. Chem. Res. 2014, 53 (5), 1841–1855.