Category: Publications

Ahmed, S. F.; Atilhan, M., Evaluating the Performance of a Newly Developed Carbon Capture Device for Mobile Emission Sources. Journal of Energy Resources Technology, Transactions of the ASME 2017, 139 (6). For further details please click here.

In the present study, a new carbon capture device that can be carried on-board vehicles has been developed and tested. The developed device uses absorption and adsorption methods of postcombustion CO2 capture. Sodium hydroxide (NaOH) pellets and calcium hydroxide Ca(OH)2 have been used as solvents and sorbents in the device. The CO2 capture efficiency has been evaluated at a wide range of operating conditions. The results showed that the higher the concentration of the solvent, the higher the capture efficiency, i.e., w 100% capture efficiency, being obtained at full saturation of NaOH. In addition, the increase in the solution temperature increases the capture efficiency up to 50 °C. Design of the gas distributer in the device has also a notable effect on CO2 capture. It was found that solvent prepared with seawater can provide high capture efficiency over a wide range of operation, but in general, it has a lower capture efficiency than that prepared by tap water. Moreover, solvents prepared by NaOH have a superior CO2 capture efficiency over those prepared by Ca(OH)2. For the adsorption technique, a 50% NaOH and 50% Ca(OH) mixture by mass has provided the highest capture efficiency compared with each sorbent when used alone.

Schematic diagram of the test rig and Illustration of the two distributer designs used with the test rig.

Altamash, T.; Atilhan, M.*; Aliyan, A.; Ullah, R.; Nasser, M.; Aparicio, S., Rheological, Thermodynamic, and Gas Solubility Properties of Phenylacetic Acid-Based Deep Eutectic Solvents. Chemical Engineering and Technology 2017, 40 (4), 778-790. For further details please click here.

Choline chloride + phenylacetic acid-based deep eutectic solvents are studied. Their most relevant experimental physicochemical properties at different mixing ratios together with the CO2 solubility data obtained in wide pressure and temperature ranges are reported. The presented materials exhibit a significant CO2 capture performance with low corrosion effect when compared with the most common amine-based CO2 capture agents. Detailed rheological measurements are carried out and various models are applied to describe the dynamic flow behavior of the solvents. The CO2 absorption mechanism is evaluated by studying the behavior of the liquid gas and interface. Due to the advantages of low cost, nontoxicity, and favorable physical properties, these solvents are an environmentally promising alternative for effective CO2 capture technological applications.

Deep eutectic solvents based on phenylacetic acid show low metal corrosivity, suitable
physicochemical properties and good CO2 solubility, and thus being promising physical
sorbents for carbon capturing purposes from power plant flue gases.

Altamash, T.; Haimour, T. S.; Tarsad, M. A.; Anaya, B.; Ali, M. H.; Aparicio, S.; Atilhan, M.*, Carbon Dioxide Solubility in Phosphonium-, Ammonium-, Sulfonyl-, and Pyrrolidinium-Based Ionic Liquids and their Mixtures at Moderate Pressures up to 10 bar. Journal of Chemical and Engineering Data 2017, 62 (4), 1310-1317. For further details please click here.

Carbon dioxide solubility in four ionic liquids (ILs) of different families with different cationic–anionic groups (tributylmethylphosphonium formate, butyltrimethylammonium bis(trifluoromethyl sulfonyl) imide, 1-methyl-1-propylpyrrolidinium dicyanamide, and 1-ethyl-3-methylimidazolium acetate) at temperature of 298 K and a pressure range from vacuum to 10 bar were studied in this work using state of the art gravimetric sorption experiments. This work provides insight information regarding CO2 solubility for IL–IL mixing effect pressures up to 10 bar and at 298 K. Density values were used to calculate molar volume of ionic liquids for further discussions on CO2solubility-molar volume relationship. Noticeably higher CO2 solubility with IL–IL hybridized systems of different family is opening a new window for research on a molecular level by simulations and intellectually designed ILs. Chemisorption behavior has been observed for the ILs that contain acetate-based anions in the structure and relevant discussion is included in this work.

Carbon Dioxide Solubility in Phosphonium-, Ammonium-, Sulfonyl-, and Pyrrolidinium-Based Ionic Liquids and their Mixtures

Aminnaji, M.; Tohidi, B.; Burgass, R.; Atilhan, M., Gas hydrate blockage removal using chemical injection in vertical pipes. Journal of Natural Gas Science and Engineering 2017, 40, 17-23. For further details please click here.

One of the problems with natural gas production in the pipes is gas hydrate formation which can lead to blockage. Although there are options to inhibit hydrate formation e.g. thermodynamic hydrate inhibitors and kinetic hydrates inhibitors, hydrate blockage can occur in some cases, e.g. underestimation of water cut production, unplanned shut-in, inappropriate inhibitor injection method or failure of inhibitor delivery. There are a number of remediation methods for hydrate blockage removal such as depressurization, chemical injection e.g. methanol and MEG, mechanical, and thermal methods. In the case of chemical useage in vertical pipes, density plays an important role and needs to be considered. In this work, the effect of chemical density on removing hydrate blockage in the vertical pipes was assessed using a long window rig. The use of methanol/MEG mixtures in removing hydrate blockage in vertical pipes could be more efficient than methanol or MEG alone. The results indicate that a mixture of methanol/MEG with a density of 1 g/cc could remove hydrate blockage successfully and efficiently. The hydrostatic pressure of aqueous phase due to chemical injection could be reduced by using methanol/MEG mixture, because the amount of methanol/MEG mixture required for removing plug could be less than methanol or MEG alone. In addition, ice formation during hydrate dissociation due to its endothermic nature should be taken into consideration during chemical injection.

Atilhan, M.*; Costa, L. T.; Aparicio, S., Elucidating the Properties of Graphene-Deep Eutectic Solvents Interface. Langmuir 2017, 33 (21), 5154-5165. For further details please click here.

The properties of five deep eutectic solvents prepared based on the selection of choline chloride ionic liquid as hydrogen bond acceptor, which are mixed with several hydrogen bond donors with selected molecular features, were studied theoretically at graphene interfaces via both density functional theory and classical molecular dynamics methods. Molecular structuring at the interfaces, angular orientation, densification, and dynamic properties were analyzed upon adsorption on the graphene surface and when the deep eutectic solvents were confined between two graphene sheets and analyzed in terms of the role of the type of hydrogen bond donor for each solvent. Likewise, the behavior of deep eutectic solvent nanodroplets on graphene was simulated leading to the calculation of contact angles and nanowetting with further studies considering the effect of an external electric field on nanodroplet properties.

Elucidating the Properties of Graphene–Deep Eutectic Solvents Interface

García, G.; Atilhan, M.; Aparicio, S., Simultaneous CO2 and SO2 capture by using ionic liquids: A theoretical approach. Physical Chemistry Chemical Physics 2017, 19 (7), 5411-5422. For further details please click here.

Density functional theory (DFT) methods were used to analyze the mechanism of interaction between acidic gases and ionic liquids based on the 1-ethyl-3-methylimidazolium cation coupled with five different anions. Single ion pairs and ionic clusters containing six ion pairs were used to model the interactions of the ionic liquids with acidic gas molecules. The properties of the systems were analyzed based on geometric properties, interaction energies and Bader’s theory. The cluster approach gives a more accurate representation of the behavior of ions and gases in the bulk liquid phase, and despite computational challenges, the cluster approach allows us to quantify interactions beyond short range ones used in the single ion pair–acidic gas model commonly applied in the literature. The results reported herein point out efficient simultaneous capturing of both gases especially for ionic liquids containing the acetate anion.

Simultaneous CO2 and SO2 capture by using ionic liquids: A theoretical approach

Herrera, C.; de Carvalho Costa, G.; Atilhan, M.; Costa, L. T.; Aparicio, S., A theoretical study on aminoacid-based ionic liquids with acid gases and water, Journal of Molecular Liquids 2017, 225, 347-356. For further details please click here.

The properties of 1-ethyl-3-methylimidazolium glycinate ionic liquid mixed with CO2, SO2 and H2O were studied using a computational chemistry approach considering classical molecular dynamics simulations and quantum chemistry calculations using density functional theory. Studies as a function of mixture composition, pressure and temperature allowed a detailed characterization at the nanoscopic level of the interaction between the acid gases and the ionic liquid as a model for the use of aminoacid-based ionic liquids for acid gas capture purposes. Likewise, the properties of aqueous mixtures were analysed considering the ubiquitous presence of water in acid gas capture industrial processes. Insights on the characteristics and strength of gas molecules – ionic liquid interactions were inferred from simulations, and thus, showing the arrangement and dynamics of gas molecules around the ions.

Qureshi, M. F.; Atilhan, M.*; Altamash, T.; Aparicio, S.; Aminnaji, M.; Tohidi, B., High-pressure gas hydrate autoclave hydraulic experiments and scale-up modeling on the effect of stirring RPM effect, Journal of Natural Gas Science and Engineering 2017, 38, 50-58. For further details please click here.

A synthetic quaternary gas mixture (Methane = 85.24%, Ethane = 10.03%, n-Hexane = 0.02 mol %, Carbon dioxide = 2.49% and Nitrogen = 2.22%) has been used to study the effect of different stirring rates between 100 and 1400 rotations per minute (RPM) on hydrate crystal formation in the high pressure autoclave cell (HPC). The experimental results obtained show that there exists a threshold limit above and below which hydrate formation decreases drastically. The results were used to determine the optimum-stirring rate at which maximum hydrate crystal formation is obtained in HPC. For the scale up purposes, using the experimental results, the dimensional analysis has been conducted on HPC to obtain optimum power and density ratio factors for the bench scale reactor system. So this work aims to facilitate the ongoing research for using hydrates for natural gas storage and transportation purposes.

2016 Nobel Prize in Chemistry was awarded to Sir James Fraser Stoddart for his work on rotazanes and catenanes towards the discovery of molecular machines. This has a special meaning for us. During his time as a WCU Professor at Korean Advanced Institute of Science and Technology (KAIST), he guided me and my colleague Prof. C.T. Yavuz for preparing a proposal on covalent organic frameworks and he kindly accepted to participate in the proposal as principle investigator. With his guidance and support we managed to produce series of work on flexible porous polymeric networks for high capacity gas storage and he assisted us to perfect our manuscripts. I congratulate him for his success, he is not only an exceptional scientist but also an exception person with great perseverance which does not need prize to be respected.

In Prof. Yavuz’s office at KAIST (Daejeon, S. Korea) after a lively discussion.

Double Salt Ionic Liquids Based on Ammonium Cations and Their Application for Co2 Capture, M. Atilhan*, B. Anaya, R. Ullah, L. T. Costa, S. Aparicio*, The Journal of Physical Chemistry C, 2016, 120 (31), pp 17829-17844. Access the manuscript by clicking here.

 

Simple ionic liquids (containing one type of cation with one type of anion) and complex mixed ionic liquids (containing several types of anions and cations, double salts) based on ammonium cations were studied in this work using a combined computational and experimental approach. Theoretical studies were carried out using classical molecular dynamics simulations. The properties and structure of these fluids and their changes upon CO2 absorption were analyzed. The fluids’ structural, energetic, and dynamic properties were considered as a function of the type of ions composing the ionic liquids together with their changes when CO2 is present as a function of CO2concentration. Likewise, experimental measurements analyze carbon capturing abilities for the studied mixed ionic liquids as a function of pressure and temperature. The reported results show that mixing two neat ammonium-based ionic liquids does not change remarkably the properties of the involved neat ionic liquids, and also the affinities for CO2 are also similar in the mixed ionic liquids. Therefore, vastly different ions should be considered when mixed ionic liquids are designed for stimulating CO2 physisorption by increasing the available volume and tuning affinity toward CO2. This work provides a nanoscopic and macroscopic characterization of complex ionic liquids and their ability for carbon capturing for the first time.

Contact

Texas A&M University at Qatar
Department of Chemical Engineering
Education City
Doha - Qatar
E-Mail: mert.atilhan (at) tamu.edu
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