Engineering Commons^™

Recent Progress In Copper-Based Catalysts For Electrochemical Co2 Reduction, Wen Lei, Wei-Ping Xiao, De-Li Wang

Journal of Electrochemistry

As the situation of energy crisis and environmental pollution become more and more serious, the electrochemical reduction of carbon dioxide (CO₂) has attracted lots of attention because of its multiple meanings such as environment, resources and economic benefits. In this paper, the state of the art electrochemical reduction of CO₂ in aqueous solution is reviewed, and the latest research progress in Cu-based catalysts with different structures and morphologies is summarized. In the end, the application prospects, opportunities and challenges of Cu-based materials are briefly presented to provide an outlook for future research directions.

Thermal Removal Of Carbon Dioxide From The Atmosphere: Energy Requirements And Scaling Issues, Ted Von Hippel

Ted von Hippel

I conduct a systems-level study of direct air capture of CO2 using techniques from thermal physics. This system relies on a combination of an efficient heat exchanger, radiative cooling, and refrigeration, all at industrial scale and operated in environments at low ambient temperatures. While technological developments will be required for such a system to operate efficiently, those developments rest on a long history of refrigeration expertise and technology, and they can be developed and tested at modest scale. I estimate that the energy required to remove CO2 via this approach is comparable to direct air capture by other techniques. The …

Analysis Of Individual Molecular Dynamics Snapshots Simulating Wetting Of Surfaces Using Spheroidal Geometric Constructions, Aleksandr Abramov, Stefan Iglauer

Research outputs 2014 to 2021

Accurate characterization of wettability of minerals is important for efficient oil recovery and carbon geosequestration. In studies where molecular dynamics simulations are used to compute the contact angle, emphasis is often placed on results or theoretical details of the simulations themselves, overlooking potentially applicable methodologies for determination of the contact angle. In this manuscript, a concept of a method utilizing spheroidal geometric constructions to estimate the contact angle of a water droplet on a silica surface in carbon dioxide atmosphere is outlined and applied to the final snapshots of two molecular dynamics simulation runs. Two carbon dioxide pressures and two …

Beneficial Reuse Of Industrial Co2 Emissions Using A Microalgae Photobioreactor: Waste Heat Utilization Assessment, Daniel T. Mohler, Michael H. Wilson, Zhen Fan, John G. Groppo, Mark Crocker

Center for Applied Energy Research Faculty and Staff Publications

Microalgae are a potential means of recycling CO₂ from industrial point sources. With this in mind, a novel photobioreactor (PBR) was designed and deployed at a coal-fired power plant. To ascertain the feasibility of using waste heat from the power plant to heat algae cultures during cold periods, two heat transfer models were constructed to quantify PBR cooling times. The first, which was based on tabulated data, material properties and the physical orientation of the PBR tubes, yielded a range of heat transfer coefficients of 19–64 W m⁻² K⁻¹ for the PBR at wind speeds of 1–10 …

Ecological Co2 Flux Of A Green Roof Ecosystem And A Typical Grassland Ecosystem, Madeline Oxner

Biological and Agricultural Engineering Undergraduate Honors Theses

The Hillside Auditorium Green Roof is a low impact development feature on the University of Arkansas campus. It retains storm water and allows plants living on the roof to take up and transpire the water. Green roofs work to mimic natural ecosystems in urban environments. A key property is ecosystem respiration, which plays a large role in the global carbon cycle and is an important biologic activity indicator. The ecosystem respiration of Hillside Auditorium Green Roof was compared to a typical grassland ecosystem at the University of Arkansas farm to determine how closely the green roof is able to mimic …

Application Of The Clayff And The Dreiding Force Fields For Modeling Of Alkylated Quartz Surfaces, Aleksandr Abramov, Stefan Iglauer

Research outputs 2014 to 2021

To extend applicability and to overcome limitations of combining rules for nonbond potential parameters, in this study, CLAYFF and DREIDING force fields are coupled at the level of atomic site charges to model quartz surfaces with chemisorpt hydrocarbons. Density functional theory and Bader charge analysis are applied to calculate charges of atoms of the OC bond connecting a quartz crystal and an alkyl group. The study demonstrates that the hydrogen atom of the quartz surface hydroxyl group can be removed and its charge can be redistributed among the oxygen and carbon atoms of the OC bond in a manner consistent …

Wettability Of Fully Hydroxylated And Alkylated (001) Α-Quartz Surface In Carbon Dioxide Atmosphere, Aleksandr Abramov, Alireza Keshavarz, Stefan Iglauer

Research outputs 2014 to 2021

Wettability of alkylated quartz surfaces is of primary importance in several technological applications, including the development of oil and gas reservoirs and carbon geo-sequestration. It is intuitively understood and experimentally confirmed that hydroxylated quartz surfaces are hydrophilic. By gradually saturating a hydroxylated (001) α-quartz surface with pentyl groups, we show using molecular dynamics simulations that the surface can also exhibit extreme hydrophobicity. Within a range of surface pentyl group density from 0.29 to 3.18/nm², the contact angle of a water droplet under 10 MPa pressure of carbon dioxide at 300 K changes from 10–20 to 180°. This study …

Surface Free Energy Of Shale Gas In Niutitang Formation In Guizhou Province, Li Xijian, Yin Xin, Li Weiwei, Liu Shangping, Zhang Pei

Coal Geology & Exploration

In order to study the adsorption mechanism of shale for gas, the isothermal adsorption experiments on shale samples from wells Fengcan 1 and Tianma 1 in Guizhou Province were carried out at 50℃, 60℃, 80℃, and the isothermal adsorption curves of CH₄ and CO₂ were plotted, the shale surface free energy was calculated and the adsorption characteristics of CH₄ and CO₂ from shale were analyzed by the surface free energy. The results show that when the temperature is constant, the surface free energy of shale gas increases with the increase of pressure, and the change of …

Effect Of Pretreatment Process On Scale Formation In The Re-Boiler Section Of Monoethylene Glycol Regeneration Plant, Ammar Al Helal, Adam Soames, Stefan Iglauer, Ahmed Barifcani, Rolf Gubner

Research outputs 2014 to 2021

Monoethylene glycol (MEG) regeneration plants often use pretreatment vessels to precipitate divalent cations, such as Fe²⁺, Ca²⁺, and Mg²⁺, in order to avoid or reduce fouling in downstream reboilers and heat exchangers. This pretreatment process operates under alkaline conditions and moderate temperatures (~ 80 °C) to accelerate the formation of low-solubility divalent salts. The objective of the present research was to determine whether the pretreatment process could be minimized, without negatively impacts on the MEG regeneration process from to the formation of scale on the heater bundle in the presence of low concentrations of …

Wettability Of Quartz Surfaces Under Carbon Dioxide Geo-Sequestration Conditions. A Theoretical Study, Aleksandr Abramov

Theses: Doctorates and Masters

The wettability of rocks under reservoir conditions is important to ensure and secure long term underground storage of carbon dioxide. The composition of those rocks vary significantly and are influenced by the fact that quartz is the second most abundant mineral in the earth's continental crust. Thus, the CO2 wettability of quartz dominates the overall CO2 trapping performance of storage and cap rocks. If depleted oil or gas reservoirs are used for storage of CO2 quartz surfaces of rocks in reservoirs which have been previously exposed to hydrocarbons might be covered with chemisorpt hydrocarbon molecules. The CO2 wettability of these …

Lipid Extraction From Spirulina Sp. And Schizochytrium Sp. Using Supercritical Co2 With Methanol, Shihong Liu, Husam A. Abu Hajar, Guy Riefler, Ben J. Stuart

Civil & Environmental Engineering Faculty Publications

Microalgae are one of the most promising feedstocks for biodiesel production due to their high lipid content and easy farming. However, the extraction of lipids from microalgae is energy intensive and costly and involves the use of toxic organic solvents. Compared with organic solvent extraction, supercritical CO₂ (SCCO₂) has demonstrated advantages through lower toxicity and no solvent-liquid separation. Due to the nonpolar nature of SCCO_2, polar organic solvents such as methanol may need to be added as a modifier in order to increase the extraction ability of SCCO₂. In this paper, pilot scale lipid …

Development Of A Uav-Based System To Monitor Air Quality Over An Oil Field, Siwen Liu

Graduate Theses & Non-Theses

The growth of hydraulic fracturing has pushed the whole petroleum industries forward. As a result, gas (mainly methane [CH4]) emissions have significantly increased over the past decades (Macey et al., 2014). Gas leaks can occur at almost all stages of a petroleum production process, such as drilling, fracking, and refining. For years, ground-based air quality monitoring has been conducted around production sites. An improved understanding of air quality would be enabled by supplementing ground-based with airborne monitoring. The latter would involve the use of unmanned aerial vehicles (UAVs) to carry a compact, portable air monitoring system. The purpose of this …

A Reference High-Pressure Co2 Adsorption Isotherm For Ammonium Zsm-5 Zeolite: Results Of An Interlaboratory Study, H. G.T. Nguyen, L. Espinal, R. D. Van Zee, M. Thommes, B. Toman, M. S.L. Hudson, E. Mangano, S. Brandani, D. P. Broom, M. J. Benham, K. Cychosz, P. Bertier, F. Yang, B. M. Krooss, R. L. Siegelman, M. Hakuman, K. Nakai, A. D. Ebner, L. Erden, J. A. Ritter, A. Moran, Orhan Talu, Y. Huang, K. S. Walton, P. Billemont, G. De Weireld

Chemical & Biomedical Engineering Faculty Publications

© 2018, The Author(s). This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess carbon dioxide adsorption isotherms on NIST Reference Material RM 8852 (ammonium ZSM-5 zeolite), at 293.15 K (20 °C) from 1 kPa up to 4.5 MPa. Eleven laboratories participated in this exercise and, for the first time, high-pressure adsorption reference data are reported using a reference material. An empirical reference equation nex=d(1+exp[(-ln(P)+a)/b])c, [nex-surface excess uptake (mmol/g), P-equilibrium pressure (MPa), a = −6.22, b = 1.97, c = 4.73, and d …

Thermal Removal Of Carbon Dioxide From The Atmosphere: Energy Requirements And Scaling Issues, Ted Von Hippel

Publications

I conduct a systems-level study of direct air capture of CO2 using techniques from thermal physics. This system relies on a combination of an efficient heat exchanger, radiative cooling, and refrigeration, all at industrial scale and operated in environments at low ambient temperatures. While technological developments will be required for such a system to operate efficiently, those developments rest on a long history of refrigeration expertise and technology, and they can be developed and tested at modest scale. I estimate that the energy required to remove CO2 via this approach is comparable to direct air capture by other techniques. The …

Absorption Of Carbon Dioxide Via Single And Blends Of Aqueous Amine Solutions And Nanofluids In Gasliquid Hollow Fiber Membrane Contactor, Zia Ur Rehman Said Rehman

Chemical and Petroleum Engineering Theses

In this work, CO₂ gas was absorbed from a gas mixture (20 vol.% CO₂ + 80 vol.% N₂) in a custom made Polyvinylidene fluoride (PVDF) hollow fiber membrane contactors by using a variety of single and blends of aqueous amine solutions and nanofluids. An ultrasonic dispersion method was used to prepare nanofluids where SiO₂ nanoparticles and carbon nanotubes (CNTs) were dispersed in deionized (DI) water without adding any surfactant. The prepared solvents were fed into the tube side of the membrane module, whereas the gas mixture was passed through the shell side. CO₂ absorption experiments were carried out using four …

Experimental And Modeling Of Co2 Removal From Gas Mixtures Using Membrane Contractors Packed With Glass Beads., Farah O.S. Abuhatab

Chemical and Petroleum Engineering Theses

Natural gas is one of the major natural resources in UAE which carries significant amounts of acid gases. For the purpose of utilizing or liquefying, the gas must be pre-treated by separating the major non-hydrocarbon gases, namely C0₂. Typical C0₂ separation processes involve separation using sorbents or solvent, cryogenic or membrane. Among these processes, the chemical absorption considered to be the most effective process to remove C0₂. However, this process carries several drawbacks such as flooding, foaming, entraining, channeling, and most importantly high capital and operating costs.

An integrated unit called gas absorption membrane (GAM) …

Experimental And Modeling Of Co₂ Removal From Gas Mixtures Using Membrane Contactors Packed With Glass Beads, Farah O. S. Abuhatab

Chemical and Petroleum Engineering Theses

Natural gas is one of the major natural resources in UAE which carries significant amounts of acid gases. For the purpose of utilizing or liquefying, the gas must be pre-treated by separating the major non-hydrocarbon gases, namely CO₂. Typical CO₂ separation processes involve separation using sorbents or solvent, cryogenic or membrane. Among these processes, the chemical absorption considered to be the most effective process to remove CO₂. However, this process carries several drawbacks such as flooding, foaming, entraining, channeling, and most importantly high capital and operating costs.

An integrated unit called gas absorption membrane (GAM) consists of combining chemical absorption …

Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity, Wanlu Li

Dissertations, Theses, and Capstone Projects

For the first-time sulfur-doped, nitrogen-doped and sulfur, nitrogen-codoped nanoporous carbons were systematically studied as catalysts for CO₂ electrochemical reduction reaction (CO₂ERR). The Faradaic efficiencies (FE) of CO and CH₄ formation were calculated to evaluate the performance of these carbons. The best catalysts showed the FE of CO and CH₄ formation of 29% and 0.76%, respectively. It was found that the overall performance in CO₂ERR dramatically increased upon the reduction pretreatment of the carbons in N₂-saturated electrolyte before the CO₂ reduction process. The pretreated carbon showed the maximum FE of CO …

Variables Governing The Initial Stages Of The Synergisms Of Ultrasonic Treatment Of Biochar In Water Saturated With Carbon Dioxide, Adedapo Reuben Adeniyi

Electronic Theses and Dissertations

This work investigates the initial stage of the synergistic processes of acoustic treatment of biochar in water saturated with CO2 (AIChE Journal, 2014;60:1054-1065). Treatments with switchgrass and miscanthus biochars have been conducted to examine the effects of acoustic intensity, biochar/H2O ratio, CO2 concentrations of the solution, and that in the headspace above the solution. The changes in biochars’ heating values, carbon and hydrogen contents, internal surface area, and pore size distribution have significant technological implications and are the focal points of this study. The miscanthus and switchgrass biochars were produced via pyrolysis process at 700 oC and 550 oC, respectively. …

Greenhouse Gas Emissions From Beef Feedlot Surface Materials As Affected By Diet, Moisture, Temperature, And Time, Bryan L. Woodbury, John E. Gilley, David B. Parker, Bobbi S. Stomer

Department of Biological Systems Engineering: Papers and Publications

A laboratory study was conducted to measure the effects of diet, moisture, temperature, and time on greenhouse gas (GHG) emissions from feedlot surface materials (FSM). The FSM were collected from open-lot pens where beef cattle were fed either a dry-rolled corn (DRC) diet containing no wet distillers grains with solubles (WDGS) or a DRC diet containing 35% WDGS. The FSM were collected, air-dried or mixed with 3.0 L of water to represent dry or wet conditions, and then incubated at temperatures of 5°C, 15°C, 25°C, or 35°C. Static flux chambers were used to quantify GHG emissions over a 14-day period. …

Ceria Nanostructured Catalysts For Conversion Of Methanol And Carbon Dioxide To Dimethyl Carbonate, Jawad Hassan A Al Drwish

Masters Theses

"In this study, three different shapes of ceria (CeO₂) nanostructures (e.g., nanooctahedra, nanocubes and nanorods) were synthesized via the hydrothermal method and screened for carbonylation reaction. Of these three shapes of nanostructures, the nanorod was doped with metals such as Ca, Ni, Cu, and Co by wet impregnation method. All materials were characterized by XRD, NH₃/CO₂-TPD, XRF, FTIR and N₂ physorption to determine the crystal size and phases, acid-base properties, metal loading, and surface properties. The obtained materials were employed as catalysts for the activation of Carbon Dioxide (CO₂) and methanol …

Water Chemistry Dynamics In Four Vernal Pools In Maine, Usa, Lydia H. Kifner

Electronic Theses and Dissertations

Vernal pools are small seasonal wetlands that are a common landscape feature that contribute to biodiversity in northeastern North American forests. However, even basic information about their biogeochemical functions, such as carbon cycling, is limited. Dissolved gas concentrations (CH₄, CO₂) and other water chemistry parameters were monitored weekly at the bottom and surface of four vernal pools in central and eastern Maine, USA, from April to August 2016. The vernal pools were supersaturated with respect to CH₄ and CO₂ at all sampling dates and locations. Concentrations of dissolved CH₄ and CO₂ ranged …

Electrocarboxylation: An Effective Process For Fixation Of Co2 Into Organic Carboxylic Acids, Huan Wang, Jia-Xing Lu

Journal of Electrochemistry

Conversion and utilization of greenhouse gas carbon dioxide (CO₂) have become more and more significant to the sustainable development of the global economy. Among them, electrocarboxylation of organic substrates is an effective process. Under mild conditions such as ambient temperature and pressure, carbocations generated by electroreduction of organic substrates can react with CO₂ into corresponding carboxylic acids. This paper introduces the recent progress of our group in electrochemical carboxylation, including electrocarboxylation of varies active organic substrates and asymmetric electrocarboxylation.

The Problem Of The Anode Electrolyte In H-Type Electrolytic Cell For Electrochemical Reduction Of Carbon Dioxide, Rui Zhang, Wei-Xin Lv, Li-Xu Lei

Journal of Electrochemistry

Electrochemical reduction of carbon dioxide (CO₂) was studied in the H-type electrolytic cell. It was found that the voltage between the cathode and the anode would increase during the long time electrolysis process, for this reason the electrolytic process would be unsustainable. After the experimental investigations carried out by constant potential electrolysis, constant current electrolysis, pH test and KHCO₃ concentration analysis of anode electrolyte before and after the electrolysis, the increase in cell voltage might be caused by the following process: H⁺, that was generated from the anodic oxygen evolution reaction, reacted with HCO_{3 …}

Ammonia And Carbon Dioxide Emissions Of Three Laying-Hen Housing Systems As Affected By Manure Accumulation Time, Timothy A. Shepherd, Hongwei Xin, John P. Stinn, Morgan D. Hayes, Yang Zhao, Hong Li

Biosystems and Agricultural Engineering Faculty Publications

Laying-hen housing design and management are the most significant factors affecting the generation and release of gaseous ammonia to the atmosphere. Transitioning the hen housing type from traditional high-rise (where manure is stored within the house for about one year) to modern manure-belt style (where manure is removed every 1 to 4 d and placed into long-term storage) has significantly improved in-barn air quality and reduced farm-level ammonia emissions. As a direct result of the advantages, 100% of new construction for U.S. egg production incorporates manure-belt systems that regularly remove manure from the houses. However, manure-belt system designs (e.g., active …

Thermoeconomic Optimization Of Cascade Refrigeration System Using Mixed Carbon Dioxide And Hydrocarbons At Low Temperature Circuit, Nasruddin Nasruddin, Arnas Arnas, Ahmad Faqih, Niccolo Giannetti

Makara Journal of Technology

Many applications and industrial processes require very low cooling temperature, such as cold storage in the biomedical field, requiring temperature below -80 °C. However, single-cycle refrigeration systems can only achieve the effective cooling temperature of -40 °C and, also, the performance of the cycle will decrease drastically for cooling temperatures lower than -35°C. Currently, most of cascade refrigeration systems use refrigerants that have ozone depletion potential (ODP) and global warming potential (GWP), therefore, in this study, a cascade system is simulated using a mixture of environmentally friendly refrigerants, namely, carbon dioxide and a hydrocarbon (propane, ethane or ethylene) as the …

Capture And Recycle Of Industrial Co2 Emissions Using Mircoalgae, Michael H. Wilson, Daniel T. Mohler, John G. Groppo, Thomas E. Grubbs, Stephanie Kesner, E. Molly Frazar, Aubrey Shea, Czarena L. Crofcheck, Mark Crocker

Center for Applied Energy Research Faculty and Staff Publications

A novel cyclic flow photobioreactor (PBR) for the capture and recycle of CO₂ using microalgae was designed and deployed at a coal-fired power plant (Duke Energy’s East Bend Station). The PBR was operated continuously during the period May–September 2015, during which algae productivity of typically 0.1–0.2 g/(L day) was obtained. Maximum CO₂ capture efficiency was achieved during peak sunlight hours, the largest recorded CO₂ emission reduction corresponding to a value of 81 % (using a sparge time of 5 s/min). On average, CO₂ capture efficiency during daylight hours was 44 %. The PBR at East Bend …

Doped Tio2 Nanowires For Applications In Dye Sensitized Solar Cells And Sacrifical Hydrogen Production, Qasem Alsharari

Electronic Thesis and Dissertation Repository

This thesis explores the synthesis of metal oxide 1-D nanowires using a sol-gel method in supercritical carbon dioxide (sc-CO₂), as an environmental friendly enabling solvent. Porous nanowires were synthesized and their performance was tested in dye sensitized solar cell and sacrifical hydrogen production. Titanium isopropoxide (TIP) was used as a precursor for titania synthesis while copper, bismuth and indium were examined as dopants, respectively. The sol-gel reactions were catalyzed by acetic acid in CO₂ at a temperature of 60 °C and pressure of 5000 psi. It was observed that acetic acid/monomer ratio > 4 produced nanowires while a …

Identifying The Presence Of Amd-Derived Soil Co₂ In Field Investigations Using Isotope Ratios, Kwame Awuah-Offei, Moagabo Mathiba, Fred J. Baldassare

Mining Engineering Faculty Research & Creative Works

Recent incidents of hazardous accumulations of CO₂ in homes on or adjacent to reclaimed mine land have been shown to be linked to neutralization reactions between acidic mine drainage and carbonate material. An efficient and economic method is necessary to identify the presence of acid mine drainage- (AMD-) derived CO₂ on reclaimed mine land, prior to construction. One approach to identify the presence of AMD-derived CO₂ is to characterize stable carbon isotope ratios of soil CO₂. To do so, a viable method is necessary to acquire soil gas samples for isotope ratio analysis. This paper …

Application Of Recycled Media And Algae-Based Anaerobic Digestate In Scenedesmus Cultivation, Xinyi E, Czarena Crofcheck, Mark Crocker

Biosystems and Agricultural Engineering Faculty Publications

To make large-algae cultivation systems sustainable, commercial fertilizer inputs should be minimized. One means of achieving this is to maximize the recycle of nutrients used in algae cultivation. In addition to recycling nutrient-containing water from algae harvesting and dewatering, after harvesting algal biomass can be used as a substrate for anaerobic digestion, which can then generate mineralized nutrients to be used for further cultivation. In this study, the effect of recycling media and using mineralized nutrients during Scenedesmus cultivation was investigated. The recycled media proved to be able to support cell growth with nutrient replenishment, and it could be recycled …