(6bc) Process Intensification for Sustainable Fuels and Energy Production

Biomass, coal, natural/shale gas, or carbonaceous wastes can be converted to liquid fuels through X-to-liquids (XTL) processes, some (coal and gas) of which are applied commercially in a number of plants around the world. One of the biggest challenges associated with XTL processes is the high capital costs of these plants. Small-scale XTL have the advantages of being less capital intensive, less risk, and have the potential of utilizing renewable resources such as biomass, sustainable sources such as waste, and gas reserves which previously could not be exploited, i.e. associated and stranded gas reserves. However, the cost per barrel of these processes still remains high, if conventional technology is employed. Novel reactive distillation processes are paving the way for a more sustainable chemical process industry that is profitable, safer and less polluting [1–3].

Research in process intensification (PI) has recently gained considerable attention due to challenges related to energy and the environment, alongside risks in capital investment decisions. These challenges necessitate the development of optimization-based computational tools for process synthesis and design, which enable the integration of multiple phenomena that occur at different scales in an intensified unit. Current efforts in the field are yielding promising results that indicate the transformation of the petrochemical industry. We have recently demonstrated that PI can play a crucial role in the production of fuels, chemicals and electricity using reactive distillation with a Fischer–Tropsch (FT) based process [4,5]. We developed an equation-oriented framework for optimal synthesis of integrated reactive distillation (RD) systems for FT processes in GAMS [6], which has recently been implemented in PYOMO [4].

To produce synthesis gas at the required H₂/CO ratio for the RD process, we are developing a membrane steam-methane reforming (SMR) model. This optimization-based model provides flexibility in both process design and operation. The excess hydrogen from the reformer is used to optimize gasoline and diesel production in the product refining sections. The models are developed in Python and the optimization of the integrated flowsheet is implemented in PYOMO. The use of the SMR with internal hydrogen separation greatly improves conversion and lowers operating conditions. This type of modular design and integration of processes, which is suitable for small-scale plants, also has the potential to ease the scalability of the process. This recent model development will be presented at this conference [P1].

The deployment of large-scale equation-oriented models in industrial Oil & Gas facilities for real-time optimization has made the use of reduced-order models (ROMs) more attractive. I am working on a project with Petrobras to develop accurate and efficient ROMs for their RECAP unit in Mauá, Brazil, and will be presenting our result at this conference [P2].

Research Experience

My PhD Thesis was on the ‘Interaction between Reaction and Phase Equilibria in the Fischer–Tropsch Reaction’ advised by Prof Diane Hildebrandt and Prof David Glasser at the University of the Witwatersrand in Johannesburg, South Africa. The aim was to develop a Fischer–Tropsch synthesis (FTS) model which formed part of the models used in the design, commissioning and start-up of a coal-to-liquids Pilot Plant in Baoji, China.

I spent a year at the University of Kentucky working on catalyst development, characterization, and testing in slurry-phase FT reactors with Prof Burtron H. Davis. This was part of an integrated process synthesis approach since I wanted to expand my experience from working with fixed beds, CSTRs, and Batch Reactors to working with three-phase slurry reactors. The insight and experienced gained from working with slurry reactors could be applied to modeling biomass conversion or other petrochemical process reactors.

As a faculty member at the University of South Africa, I decided to expand my research area to consider renewable energy sources. I advised a PhD student (amongst others) on the conversion of glycerol and water through solar photocatalysis for the production of hydrogen. This project was part of an integrated approach where the waste product of one process (Biodiesel Production) is used to produce something useful (hydrogen) using a renewable energy source (solar energy). This led to a development of a high activity catalyst using titanium hollow spheres as support.

I spent a year at Texas A&M Energy Institute under the Mentorship of Prof Christodoulos A. Floudas working on hybrid energy systems. This gave me exposure to applying mixed-integer nonlinear programming techniques to optimize processes and to developing mathematical models that make use of advanced computational tools to solve complex engineering problems.

Teaching Interests:

I was a Senior Lecturer (Assistant Professor) in Chemical Engineering at the University of South Africa from 2012–2015, and was an Associate Professor from 2016–2018. I advised Masters and PhD students and taught:

PCT402C: Process Control IV,

RTE4701: Reactor Technology IV.

I am committed to excellence in teaching. With my extensive teaching experience and my strong background in chemical and systems engineering, I am well-suited for the instruction of a wide range of undergraduate and graduate subjects as well as develop my own courses focusing on Process Intensification with its application to Sustainable Energy Processes.

Masters and Doctoral Students Supervision

I have advised one PhD and two Masters students to completion at the University of South Africa; and have co-advised three Masters students to completion at Carnegie Mellon University.

Research Grants as a Principal Investigator

National Research Foundation of South Africa, Thuthuka Grant Holder: 2018–2020

Grant no: 113652; Value per annum: R432,000.00 (approximately $30,857).

National Research Foundation, Knowledge Interchange and Collaboration: 2017

Grant no: 110240, Total value: R23,000.00 (approximately $1,643).

Vision Keepers Support Program: 2016–2018

From: University of South Africa, Value per annum: R177,534.72 (approximately $12,681)

Emerging Researcher Support Program: 2016–2018

From: University of South Africa, Value per annum: R845,804.40 (approximately $60,415)

National Research Foundation of South Africa, Thuthuka Grant Holder: 2015–2017

Grant no: 94090; Value per annum: R494,800.00 (approximately $35,343).

Future Direction

As faculty, I aim to lead a research group that uses process systems engineering concepts and catalysis fundamentals for applications in energy processes and the environment. Our work will rely heavily on the use core chemical engineering principles and advanced computational algorithms designed to enhance decision making in complex engineering systems.

I believe in the great value of collaborations and have demonstrated it in numerous projects with colleagues from both academia and industry. I am especially interested in exploring potential collaborations in catalysis, reaction engineering, thermodynamic modeling, systems design and optimization of energy- and sustainability-related projects.

Service

I have been extensively involved in community engagement activities and have mentored and advised students from previously disadvantaged backgrounds and thus should be able to contribute positively to faculty diversity and to working with minorities. I am an approachable, hardworking, enthusiastic, motivated and focused individual with effective interpersonal and communication skills. I can communicate complex and conceptual ideas to students as well as to peers using high level skills and a range of media.

Presentations at the current AIChE Annual Meeting

[P1] Modular gas-to-liquids process with membrane steam-methane reformer, Fischer–Tropsch reactive distillation and integrated product refining. Topical Conference: Advances in Fossil Energy R&D: Design and Optimization of Environmentally Sustainable Advanced Fossil Energy Systems.

[P2] Reduced-order model for a large-scale real-time optimization of a residue fluidized catalytic cracker. Session: Industrial Applications in Design and Operations.

Selected Recent Publications

[1] C.M. Masuku, L.T. Biegler, Recent advances in gas-to-liquids process intensification with emphasis on reactive distillation, Curr. Opin. Chem. Eng. 22 (2019) https://doi.org/10.1016/j.coche.2018.12.009.

[2] W.D. Shafer, M.K. Gnanamani, U. Graham, J. Yang, C.M. Masuku, G. Jacobs, B.H. Davis, Fischer–Tropsch: product distribution – The fingerprint of synthetic fuels, Catalysts 9 (2019) 259.

[3] T.W.P. Seadira, G. Sadanandam, T. Ntho, C.M. Masuku, M.S. Scurrell, Preparation and characterization of metals supported on nanostructured TiO₂ hollow spheres for production of hydrogen via photocatalytic reforming of glycerol, Appl. Catal. B Environ. 222 (2018) 133 – 145.

[4] N. He, Y. Hu, C.M. Masuku, L.T. Biegler, 110^th Anniversary: Fischer–Tropsch synthesis for multiphase product recovery through reactive distillation, Ind. Eng. Res. Chem. 58 (2019) https://doi.org/10.1021/acs.iecr.9b02352.

[5] Y. Zhang, C.M. Masuku, L.T. Biegler, An MPCC reactive distillation optimization model for multi-objective Fischer–Tropsch synthesis, Comput. Aided Chem. Eng. 46 (2019) 451–456.

[6] Y. Zhang, C.M. Masuku, L.T. Biegler, Equation-oriented framework for optimal synthesis of integrated reactive distillation systems for the Fischer–Tropsch processes, Energy Fuels 32 (2018) 7199–7209.

Keywords: Fischer–Tropsch Synthesis, Catalysis and Reaction Engineering, Process Synthesis and Optimization, Process Intensification, Sustainable and Renewable Process Design.