(56g) Nano-Scale Modifications Promote the Success in Industrial Scale: Catalytic Modified Oxygen Carriers for Advanced Fuel Combustion and Gasification System

With the existence of severe global warming issue, it is in great need to develop and successfully commercialize clean fuel conversion technologies. Among all the technologies, the chemical looping technologies have multiple applications in fuel combustion as well as methane, coal and biomass reforming. The greatest advantage of chemical looping process is that it can result in a dramatic reduction of capital cost required for the process and improvement of carbon utilization efficiency.

However, the success of the commercialization of the chemical looping system is dependent on oxygen carriers’ reactivity and recyclability, whose mechanism requires studies from nano-scale. The core of oxygen carriers’ efficiency relies on complex redox reactions involving hydrocarbon molecule absorption and dissociation on metal-oxide based oxygen carrier surfaces, lattice oxygen ion diffusion, oxygen vacancy creation and annihilation at high temperatures. We utilize iron-based materials for oxygen carriers of chemical looping process. Low cost, multiple phases and environmentally-friendly nature of iron oxide leads to the industrial potential of chemical looping utilization. However, the moderate reactivity and selectivity of iron oxide with fuel reaction still impede the success of the commercialization of chemical looping process, where improvement is needed.

Nano-Scale and Lab-Scale Studies:

With a thorough understanding in the mechanism between the reaction of methane and oxygen carriers through density functional theory (DFT) and several years of research with characterization using XRD, XPS, SEM, TEM, and MS. I, with my colleagues:

• Invented catalytic doping method for oxygen carriers to increase the reactivity by 3 times with better recyclability and negligible cost augment
• Created hybrid materials, which increased the selectivity of syngas from 60% to around 95%

I published 7 papers with my first or leading authorships in this area (3 selected papers are shown below):

• Cobalt Doping Modification for Enhanced Methane Conversion at Low Temperature in Chemical Looping Reforming Systems. Catalysis Today, (in progress). (2019)
• Enhanced Methane Conversion in Chemical Looping Partial Oxidation Systems Using a Copper Doping Modification. Applied Catalysis B: Environmental, 235, 143-149. (2018)
• Impact of 1% Lanthanum Dopant on Carbonaceous Fuel Redox Reactions with an Iron-Based Oxygen Carrier in Chemical Looping Processes. ACS Energy Letters, 2, 70–74. (2016)

In addition, I took the lead in 2 funded projects from OH Development Service Agency (ODSA):

• Redox Mechanism Study of Iron-Based Oxygen Carriers in Coal-Direct Chemical Looping Reactions
• Catalytic dopant in modified oxygen carriers for coal-direct chemical looping applications

Bench-Scale and Sub-pilot-Scale Tests:

We invented our new particle based on our nanoscale knowledge and tested their properties in lab-scale. The ultimate goal of oxygen carriers’ development is commercialization. By co-operation with the other people in our group, I tested the new particles in bench-scale and sub-pilot scale, where I studied the kinetics of the particle by using machine learning fitting and core-shell model. In order to finish these tasks, I learned Java, Python, C, Matlab and Machine Learning during my spare time. I utilized the knowledge and:

• Tested particles in syngas generation and fuel combustion as the bench unit, gaining a conversion of fuel higher than 98% with 90% syngas selectivity or 99% fuel combustion
• Built an automatic program in the labs to control gas injection without manual handling
• Constructed the program with automatic data analysis and graph depicting, leading to a 10 times faster experimental efficiency

2 papers were published for the bench scale and sub-pilot scale test with my leading authorship (and two papers about kinetic model are in progress):

• High Purity Syngas and Hydrogen Coproduction Using Copper-iron Oxygen Carriers in Chemical Looping Reforming Process. Applied Energy, 235, 1415-1426. (2019)
• A Novel Chemical Looping Partial Oxidation Process for Thermal Oxidation Process for Thermochemical Conversion of Biomass to Syngas. Applied Energy, 222, 119-131. (2018)

Meanwhile, I made great contributions to several funded projects from US Department of Energy (DOE) and ODSA:

• Biomass gasification for chemical production using chemical looping techniques
• Chemical looping coal gasification sub-pilot unit demonstration and economics assessment for IGCC application

Pilot-Scale Operation:

Finally, we tested our modified particles in our pilot scale units both in National Carbon Capture Center (NCCC) for Syngas Chemical Looping (SCL) system and Babcock & Wilcox (B&W) for Coal Direct Chemical Looping (CDCL) system. As a member of running the pilot scale unit:

• We achieved both 1000 hours of steady solid circulation operation for both unit with more than 100 hours steady fuel injection and 95% or higher fuel conversion
• I led a programming team for lab-scale and pilot-scale data analysis using andvanced MATLAB and Python techniques and skills
• I led the modification and safety inspection (HAZOP, lockout tag-out) process and a professional team for setting up and maintaining gas analyzer for pilot plant operation
• I negotiated and communicated with technical engineers on the operation site, focusing on scheme decision, design modification and schedule planning with my extraordinarily communication skills for industrial cooperation

We published a paper for NCCC operation and another paper for B&W unit is undergoing:

• 250 kW_th High Pressure Pilot Demonstration of the Syngas Chemical Looping System for High Purity H₂ Production with CO₂Applied Energy, 230, 1660-1672. (2018)

I also made great contributions to these two large funded projects (each with more than 5 millions dollars) from National Energy Technology Laboratory (NETL) and DOE:

• Pilot scale operation and testing of syngas chemical looping for hydrogen production
• Commercialization of an atmospheric iron-based coal direct chemical looping process for power production 10 MWE coal direct chemical looping large pilot plant – Pre-front end engineering and design (pre-feed) study

Carbon Materials and Batteries Experiences:

In addition, I’m also experienced in studies of carbon nanomaterials (carbon nanotubes and graphene) and lithium related batteries. I led an undergraduate group and created phosphoric acid modified carbon nanotubes/sulfur composite as cathode material for lithium-sulfur batteries with enhanced lithium storage performance and long-term cycling stability. I published two papers with first and leading authorship in this area:

• Hydrothermal Synthesis of Porous Phosphorus-doped Carbon Nanotubes and Their Use in the Oxygen Reduction Reaction and Lithium-Sulfur Batteries. New Carbon Materials, 31(3), 352–362. (2016) (27 citations)
• Strongly Coupled Interfaces between A Heterogeneous Carbon Host and A Sulfur-containing Guest for Highly Stable Lithium-Sulfur Batteries: Mechanistic Insight into Capacity Degradation. Advanced Materials Interfaces, 1(7). (2014) (221 citations)

Teaching:

Except for research, I am also an excellent teaching assistant in Transport Phenomena and Process Design, Economics, & Strategy class. As a teaching assistant with the responsibilities of helping both the professor and undergraduate students:

• I led a teaching assistant team for homework grading, exam grading, office hour teaching, and feedback collecting from students to professors
• I designed homework, checked the solutions for examination, and made corrections on those errors during the office hours
• I communicated with students about their study plans, research interests, and how to use the course knowledge from their research to their everyday lives, providing them a deeper understanding of the courses

Meanwhile, I am a mentor of two undergraduate students and several Ph. D. students. As a mentor of the undergraduate students:

• I helped them to study experiment skills, such as TGA, sol-gel synthesis, XRD, and simulation skills, such as MATLAB and Aspen Simulation
• I guided them in how to read papers, how to think creatively, how to schedule the experiments, and how to start their own research
• I inspired them to set the goal to finish their undergraduate theses

As a mentor of the graduate students, not only did I help them in areas above, I also:

• assisted them in learning how to run the system during the 1000 hours operation
• instructed them to get familiar with our pilot scale facility and gave them some suggestions and ideas about their research and theses

My studies in nanoscale promote the success of industrial scale, and my industrial scale experiences prepared me a great candidate with the capability of creative thinking from all scales, and thus enabled me to make a big difference for industrial work.

Technical and scientific skills:

• Experimental skills: X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Focused Ion Beam (FIB), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), Energy-dispersive X-ray spectroscopy (EDS), Thermogravimetric Analysis (TGA), Mass Spectrometer (MS), Gas Analyzer, FTIR
• Process design: Pilot Unit Operation, HAZOP, Sub-pilot Unit Operation, Bench Unit Operation, Fixed Bed Reactor, U-tube Reactor
• Simulation: Aspen Plus, Factsage, Density Functional Theory (DFT), Applied Machine Learning, Applied Data Science
• Programming: Python, Java, C; Matlab, Pandas, Numpy, Scipy, Sklearn
• Software: Microsoft Office, Photoshop, Origin, AutoCAD, Premiere, Dac-Factory