Kansas State Chemical Engineering Research Areas
Biofuels and biobased products can improve environmental quality, rural economies, and national security through the cross-disciplinary efforts of scientists and engineers with an appreciation for the complexity of the societal, technological, and scientific issues involved. Key to success in this field is efficient reactions and biorefining, the separation of biologically derived, high value chemicals. Compared to the processing of petrochemical products, bio-based refining technology is still at its infancy. Recent efforts have focused on developing bio-based specific processing technology. However, the majority of the ongoing research in this field is devoted towards fuels rather than chemicals. The importance of chemicals can be realized from the fact that petrochemicals consume only 3.4% of the crude oil in a refinery but generate revenue roughly equivalent to fuels, which consume 70.6% of the crude oil. To realize a high return on investment, it is imperative for a biorefinery to produce industrially useful chemicals along with fuels.
This research is focused on membrane reactor technology to promote succinic acid hydrogenation at mild operating conditions (1 atm pressure). Asymmetric membranes with a thin, defect-free polymer layer are employed as a contactor between the aqueous-phase and gas phase hydrogen. The skin of the membrane contactor is decorated with metal catalytic sites. The aqueous feed solution is continuously pumped past the catalytic surface and hydrogen is supplied from the permeate side. Characterization of the membrane is performed, as defects in the skin layer and the thickness of this layer play an important role in regulating the supply hydrogen to the catalyst surface. This research examines the effect of membrane flux, presence of skin-layer defects, and catalyst loading on the performance of the membrane reactor system.
The production of ammonia, commonly used in agriculture as a fertilizer, consumes several percent of the world's energy budget. . Producing a pound of ammonia currently consumes more than a pound of natural gas The increasing demand for food along with plans to use more biomass to produce fuels point towards increasing demand for fertilizers (and thereby ammonia) for many years to come. In addition, the options of using ammonia as a fuel in diesel engines or as a hydrogen carrier for an on-board hydrogen supply for vehicles are currently being investigated elsewhere.
At K-State, the potential of using solar energy to produce ammonia at mild process conditions is being explored. The goal is to create a sustainable production of ammonia based on an inorganic reaction cycle driven by concentrated sunlight. The overall cycle converts water, air and biomass or another carbon source into ammonia and valuable syngas. Both ammonia and syngas can be used as energy carrier or as feedstock for chemical synthesis.
Another approach integrates solar hydrogen production with the ammonia synthesis process with the benefit of converting solar-derived hydrogen to an easily stored and transported form (ammonia). No carbon source is needed. Ammonia easily exceeds the current benchmarks for hydrogen storage approaches set by the U.S. Department of Energy in regard to a hydrogen economy.
This project is supported by the NSF IGERT program "I-STAR BioEnergy" at Kansa State University. Experimental research, process design, and economic evaluation are integrated for this project.
Ethanol from fermentation processes is produced widely in Brazil, and the U.S. has embarked on a path to reach very significant ethanol production using fermentation. All fermentation-based ethanol production faces the issue of the energy intensive ethanol/water separation following fermentation. This is especially true for cellulosic-based bio-ethanol that produces rather dilute ethanol/water mixtures due to the fermentation parameters.
This project explores the use of salt-extractive distillation enabled by a membrane-based salt recycling process to lower the energy demand of the ethanol/water separation. Calcium chloride can greatly improve distillation performance. Electrodialysis is used to recover salt from the distillation process and recycle it. Process simulation including customized thermodynamics and economic evaluation is used to integrate the experimental design parameters for the membrane process in the intricate separation network to recover fuel grade ethanol from fermentation broth. Significant energy savings will accrue, and this will help to improve the energy balance and sustainability of bioethanol.
A multi-disciplinary collaboration between Dr.'s Amanor-Boadu (Agricultural Economics), Nelson (Resources), and Pfromm (Engineering) has resulted in an initial publication on the technological sustainability of algae-based diesel that has found some resonance. Several publications have already taken note of the work. The second part of this sustainability analysis for algae diesel (economic sustainability interrogated by dynamic stochastic economic evaluation) is in review for publication.
The project team anticipated to apply their interdisciplinary approach to sustainability to more processes in the future.
Ionic liquids are organic compounds that are composed of ions and are liquids near room temperature. They are a good alternative to water as a solvent, in part because of their extremely low vapor pressures. Their specific properties can be tailored by changing their molecular structure, specifically the ligands composing the molecules. Research is focusing on using a combination of solubility and spectroscopy measurements, thermodynamic theory, and molecular modeling to study nanoporous materials made via ionothermal synthesis, where the solvent is an ionic liquid. The effect of systematic changes to the ionic liquid structure on the interactions with the nanomaterial precursors and how that in turn affects the formation of the final material are under investigation. This work is developing (1) the first solubility measurements of nanomaterial precursors in ionic liquids, (2) thermodynamic models to describe the phase behavior of the precursors and ionic liquids, (3) the crucial validation of molecular dynamics simulations for ionic liquid / precursor systems, (4) the quantification of the chemical complexes formed between the solute and solvent in the initial stages of zeolite synthesis, and (5) the elucidation of trends between the solute/solvent phase behavior and material formation that will be used to rationally select ionic liquids solvents for synthesis of novel nanoporous materials.
Dr. Glasgow’s principal interests concern the interaction of turbulence with fluid-borne entities in multi-phase processes. Specific areas of study include flocculation, aggregate breakage, aggregate deformation, the expulsion of interstitial fluid from floc structures, and the effects of oscillatory fluid motions upon interphase transport. In addition, he has investigated bubble formation, coalescence and breakage in aerated reactors, the effects of energetic interfacial phenomena upon cells in culture, and the impulsive distribution of small particles in air-filled chambers. He has also initiated a study of the effectiveness of a passive mixing device for the treatment of agricultural wastewaters.
My research projects have two emphases: the application of spectroscopic and thermal analysis techniques to chemical engineering problems and the use of biorenewable resources as feedstocks for engineering materials. Currently infrared spectroscopic methods are being developed to monitor in situ the early stages in the synthesis of mesoporous materials (in collaboration with Dr. Anthony).
Heterogeneous catalysis is important for increasing the efficiency and reducing the cost to produce valuable chemicals. This is especially true for energy production. There are three current projects in this area ongoing in the chemical engineering department at K-State.
In the first project, new catalysts are being developed for converting biomass to fuels and chemicals that are easily separable from the feed and product stocks. Magnetic nanoparticles are being acid-functionalized to break down cellulose to fermentable sugars. The nanoparticles offer a number of advantages over other acid catalysts: they are easily separable using a magnet, their acidity can be modified through choice of functional group, and they are reusable.
In the second project, a hybrid biochemical/catalytic processes is being developed to produce chemicals from biomass. In this approach, fermentation converts biomass to useful intermediate chemicals (such as 2,3-butanediol) which are then converted to chemicals like methyl ethyl ketone or a liquid fuel-percursor like butene. By using both biochemical and catalytic processes, we are harnessing the positive featurs of each (fermentation can be highly specific to one product, catalytic reactions can be very fast) while minimizing their negative aspects (fermentation can be slow, catalytic reactions are not always selective).
A final research interest is the production of hydrogen from liquid fuels through catalytic partial oxidation. Bimetallic catalysts are being developed to convert military logistic fuels, like JP-8, to hydrogen, where it can be used in fuel cells for portable power generation. The bimetallic Pt/Ni catalysts being developed offer a number of advantages: catalyst cost is decreased by replacing some Pt with Ni and the two metals offer complementary features (Pt is very active for oxidation, while Ni is active for steam reforming reactions).
All projects include synthesize of the catalysts, characterization of their physical and chemical properties using a variety of techniques (x-ray photoelectron spectroscopy, infrared spectroscopy, temperature-programmed methods, x-ray diffraction), and testing their catalyst activity for the reaction of interest.
Semiconductors are the key component in many solid state devices including diodes and transistors in integrated circuits for computers and cell phones, and light emitting diodes (LEDs), and laser diodes (LDs) for general illumination, information displays, and DVD and blu ray players. Important advantages of solid state devices are their low power requirements, speed, low cost, compactness, and robust nature (resistance to impact damage).
Three boron compound semiconductors, boron nitride (BN), boron phosphide (BP), and icosahedral boron arsenide (B12As2) are being studied at K-State for their potential applications in radiation detection and radioisotope batteries. These semiconductors have properties that are distinctively different than the most commonly used semiconductors, such as silicon and gallium arsenide. For example, one isotope of boron (B-10) reacts strongly with neutrons - much more strongly than most elements. This reaction produces charged particles that are relatively easy to detect, making a solid state neutron detector possible. Such neutron detectors would find applications in homeland security, medical diagnostics, petroleum exploration, and fundamental science. These could provide a low-cost alternative to the most common neutron detectors which rely on helium-3, a particular scarce and expensive isotope of helium.
Some boron compound semiconductors are extraordinary resistant to radiation damage. Under intense radiation, the electrical properties of most semiconductors quickly degrade, leading to device failure. In contrast, such failure could be avoided in devices based on icosahedral boron arsenide. An intriguing application of this property is the betacell, a device that directly converts nuclear energy to electrical energy. These devices could take advantage of the enormous energy densities of nuclear energy sources, that can be ten thousand times higher than gasoline. Nuclear sources can also provide energy for decades, much longer than chemical batteries.
At K-State, we are focusing on developing synthesis techniques that produce boron compound semiconductors of high crystal perfection with low residual impurity concentrations. Bulk crystals are produced by precipitation from molten metal solutions, and thin films are prepared by chemical vapor deposition. The former produces relatively thick crystals with low defect densities, while the latter produces thin films either with low residual impurity concentrations or with intentionally added impurities to achieve certain electrical properties. The structural, optical, chemical, and electrical properties of these materials are characterized to provide feedback for optimizing the synthesis process. Through further process optimization, the goals are to produce these materials that are suitable for the novel electronic devices envisioned.
The properties of the semiconductor gallium nitride are favorable for high power, high frequency, and high temperature electronics. Applications include power amplifiers for radar in military applications and automobile collision avoidance, base stations for cell phones, and hybrid car power electronics. However, designers of its electronic devices have generally avoided using insulating layers, due to the poor electrical properties of the insulator-semiconductor interface. Insulating layers are almost universally found in silicon-based electronic devices, because they enable much larger voltage swings and result in greatly reduced leakage currents. These benefits could also be realized with gallium nitride devices, if a technology for preparing a good insulator on semiconductor can be found.
The technology to do this is being developed at K-State with collaborators at the Naval Research Laboratory. The properties of the insulator-gallium nitride interface are being optimized by developing an understanding of how process conditions impact the properties. First, insulators with high dielectric constants such as alumina (Al2O3) and titanium dioxide (TiO2) are deposited on GaN by atomic layer deposition. Then the morphology, structure, and composition of the oxides are established, through detailed characterization. Next, the electrical properties are measured, trends are identified, and these are interpreted based on the physical and chemical properties. The goal is to establish the most important properties that are necessary, so as to produce high quality electronic device performance. This technology would greatly improve the versatility of this semiconductor.
Graphene, two dimensional sheets of carbon that are a single atom thick, exhibits many unique mechanical, optical, and electronic properties that have the potential for many device applications. Recent theories have shown that by controllably manipulating graphene’s structure and chemistry, its properties can be tuned over a broad range, and new quantum-physics can be realized. Synthesis and property characterization studies at K-State include the study of graphene, which was (a) chemically modified with gold nanostructures; (b) functionalized via metal-coordination bonds; (c) nanostructured into quantum dots and nanoribbons; (d) composited with biocompatible polymer to produce bacterial repellant paper; (e) functionalized with molecular machine; and (f) modified into a molecular protein-carpet to wrap bacterial cells for enhanced electron-microscopy imaging.
Similar studies are also being applied to hexagonal boron nitride, another material that forms atomically thin two dimensional sheets. It’s properties are distinctly different: while graphene is typically a conductor, boron nitride is an insulator. A K-State, a novel process was developed to exfoliate boron-nitride atomically thick sheets with the highest yield reported till date. Research to chemically functionalize boron nitride sheets is on-going.
Recent highlights with graphene include developing: (1) true-scale imaging of bacterial cells under electron-microscope by wrapping the cells with impermeable graphene to prevent water loss; (2) a process to produce graphene nanostructures with unprecedented structural control over its length and width dimensions; (3) a process to functionalize graphene while retaining its high charge carrier mobility (a major current challenge hampering graphene research); and (4) a graphene-based-device capable of detecting molecular mechanics.
Chemical engineers have expertise to work on environmental problems related to sustainable energy, environmental management, and sustainability. There are several research problems related to air emissions and liquid and solid effluents from industrial and agricultural processes. One current problem is the development of a treatment wetland to manage sulfur and other inorganic compounds in flue gas desulfurization waste water from a coal burning power plant. The research involves both mathematical models and experimental work. Faculty and students from four departments are working with a consulting company as a multidisciplinary team. New technology development to address environmental problems and advance sustainability is a second area of research.
This cooperative project with the Biological and Agricultural Engineering Department sponsored by the Agriculture Experiment Station aims at the comprehensive analysis and optimal synthesis of systems for mitigation of pollutant and pathogen emissions from livestock sources and operations involving wide-ranging activities. Such activities include the operation and management of beef cattle feedlots, swine buildings, dairy barns and poultry farms. The expected outcomes of the project will be the optimal systems synthesized, which will provide the definitive framework for the design, operation, control, and management of sustainable infrastructures and facilities for reducing and/or eliminating pollutants and pathogens in a variety of livestock operations. The project will be executed as follows.
First, additional processes available for mitigation of pollutant and pathogen emissions from livestock sources and operations will be thoroughly searched and identified, thus augmenting those already generated or collected by the project members. Second, the domain knowledge and data pertaining to the characteristics and behavior of the processes identified will be systematically compiled and logically categorized. Moreover, the consistency of the data compiled will be statistically assessed within each of the categories established. Third, the processes identified will be modeled based on the domain knowledge and data pertaining to them by resorting to deterministic and stochastic approaches. The resultant mechanistic models will be simulated via conventional numerical techniques as well as stochastic simulation methods, e.g., the Monte Carlo method, under a wide range of realistic scenarios. Fourth, the systems’ optimal configurations will be determined, i.e., the optimal systems will be synthesized, by incorporating the processes identified and classified at the outset by mainly resorting to the graph-theoretic method based on process graphs (P-graphs). Nevertheless, if the system of interest comprises a small number of functioning units, it can be synthesized via a heuristic or conventional algorithmic method. Fifth, the sustainability of the optimal systems synthesized will be assessed in light of various criteria, such as cost, energy requirement, exergy consumption, material requirements, and environmental impacts. An initial estimation of the sustainability will be performed through the method of sustainability potential; if the resultant potential is deemed favorable, it will be further assessed by one or more of the available methods for the evaluation of sustainability.
Whenever necessary or desirable, some statistically designed laboratory and field experiments will be carried out to generate supplementary data, confirm the results of modeling and simulation, and/or assess the performance of synthesized systems.