(177b) A Process Design Framework for Utilizing Unconventional Feedstocks

Increasing global need for chemicals and commodity products is a major motivation for utilizing unconventional feedstocks such as stranded natural gas, biogas, contaminated shale gas, and coalbed methane. These feedstocks pose new design challenges due to their small-scale and distributed nature as well as the presence of significant spatio-temporal variabilities in feedstock availability and quality. To this end, we propose a new framework for designing small-scale chemical processes that reduces the capital intensity through dynamic process intensification (DPI) and strikes a balance between economies-of-scale and economies-of-numbers through functionality-based standardization of flexible modular units. A generalized reaction-adsorption modeling and simulation (GRAMS) platform is used for accurately capturing dynamically intensified sorption enhanced reaction process (SERP) alternatives that exploit periodic reaction and separation phenomena in a single unit operation [1]. The key modeling contributions include an extensive and generalized boundary-condition formulation for representing different operation modes in a DPI system, and the use of continuous pressure variables for selecting discrete operation modes and flow directions [2,3]. As a result, the framework is capable of simultaneously optimizing periodic cycle configuration, column design specifications and process operating conditions. The functionality-based equipment standardization also departs from asynchronous design of single-processes and adopts a simultaneous approach for the concurrent design of multiple small-scale processes [4]. This provides new opportunities for reducing the capital intensity via economies-of-numbers. The utility of the developed frameworks is demonstrated through several case studies fundamental to both midstream and downstream unconventional natural gas supply chains. For midstream applications, we design cost-effective processes for natural gas purification and natural gas liquids (NGL) fractionation. For downstream applications, the specific applications of interest include the production of intermediate and end-use chemicals such as methanol, ammonia and hydrogen using natural gas as the raw material feedstock.

References

[1] A. Arora, S.S. Iyer, M.M.F. Hasan, GRAMS: A General Framework Describing Adsorption, Reaction and Sorption-Enhanced Reaction Processes, Chem. Eng. Sci. 192 (2018) 335–358.

[2] A. Arora, I. Bajaj, S.S. Iyer, M.M.F. Hasan, Optimal Synthesis of Periodic Sorption Enhanced Reaction Processes with Application to Hydrogen Production, Comput. Chem. Eng. 115 (2018) 89–111.

[3] A. Arora, S.S. Iyer, I. Bajaj, M.M.F. Hasan, Optimal Methanol Production via Sorption Enhanced Reaction Process, Ind. Eng. Chem. Res. 57 (2018) 14143–14161.

[4] A. Arora, J. Li, M.S. Zantye, M.M.F. Hasan, Design standardization of unit operations for reducing the capital intensity and cost of small-scale chemical processes, AIChE J. 66 (2020) e16802.