Advances in Chemical Engineering and Science

Journal Information
ISSN / EISSN : 2160-0392 / 2160-0406
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 455
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Chris A. Van Roekel, David T. Montgomery, Jaswinder Singh, Daniel B. Olsen
Advances in Chemical Engineering and Science, Volume 12, pp 114-129; https://doi.org/10.4236/aces.2022.122009

Abstract:
Rich burn industrial natural gas engines offer best in class post catalyst emissions by using a non-selective catalyst reduction aftertreatment technology. However, they operate with reduced power density when compared to lean burn engines. Dedicated exhaust gas recirculation (EGR) offers a possible pathway for rich burn engines to use non-selective catalyst reduction aftertreatment technology without sacrificing power density. In order to achieve best in class post catalyst emissions, the precious metals and washcoat of a non-selective catalyst must be designed according to the expected exhaust composition of an engine. In this work, a rich burn industrial natural gas engine operating with dedicated EGR was paired with a commercially available non-selective catalyst. At rated brake mean effective pressure (BMEP) the air-fuel ratio was swept between rich and lean conditions to compare the catalyst reduction efficiency and post catalyst emissions of rich burn and dedicated EGR combustion. It was found that due to low oxides of nitrogen (NOx) emissions across the entire air-fuel ratio range, dedicated EGR offers a much larger range of air-fuel ratios where low regulated emissions can be met. Low engine out NOx also points towards a possibility of using an oxidation catalyst rather than a non-selective catalyst for dedicated EGR applications. The location of the NOx-CO tradeoff was shifted to more rich conditions using dedicated EGR.
Nam Joong Jeon, Jangwon Seo, Sanghee Nah, Jung-Keun Lee
Advances in Chemical Engineering and Science, Volume 12, pp 54-64; https://doi.org/10.4236/aces.2022.121005

Abstract:
FAPbI3 and FA(Mn:Pb)I3 perovskite films were prepared and evaluated through steady and transient absorption spectroscopy. According to the analysis using Elliot’s model, there were no considerable differences except for the absorption intensity between FAPbI3 and FA(Mn:Pb)I3 perovskite films: the value of the optical gap (Eg) and the position of exciton resonance (E0) were the same. The femtosecond transient absorption showed biexponential relaxation properties of the charge carriers, suggesting that biexcitons are more easily generated in FA(Mn:Pb)I3 than FAPbI3 perovskite. The generation of biexcitons in FA(Mn:Pb)I3 was also confirmed by the photon pump fluence dependence. Moreover, we were able to estimate the average number of absorbed photons directly from the photon pump power dependence without needing any further experimental measurements such as photoluminescence. Our findings may offer a new way of understanding photoinduced carrier dynamics in perovskite manganites.
Uwem Ekwere Inyang, Iniubong James Uwa
Advances in Chemical Engineering and Science, Volume 12, pp 26-39; https://doi.org/10.4236/aces.2022.121003

Abstract:
The research paper tends to review the effectiveness of helical coil in heat exchangers (HCHE). Heat exchanger is a device used in transferring thermal energy between two or more fluids or solid interfaces and a fluid, in solid particulates and a fluid at different temperatures and thermal contact. The author has concisely discussed the helical coil in heat exchanger at different shapes and conditions and compared the HCHE with straight tubes heat exchangers, and the factors affecting the performance and effectiveness of the helical coil heat exchanger such as the curvature ratio, and other heat exchangers. The author demonstrated that the HCHE provided more excellent heat transfer performance and effectiveness than straight tubes and other heat exchangers because of secondary flow development inside the helical tube, and heat transfer coefficient increased with an increase in the curvature ratio of HCHE for the same flow rates. The secondary flow and mass flow rates, advantages and disadvantages have also been reviewed. The authors back their findings with available theories. Suitable fluid should be searched for high efficiency in the helical coil.
Edwin Atego, John O. Agumba, Godfrey O. Barasa
Advances in Chemical Engineering and Science, Volume 12, pp 1-12; https://doi.org/10.4236/aces.2022.121001

Abstract:
Over the recent years, the global increase of electronic wastes from electrical and electronic devices (e-wastes) has been on an alarming trend in quantity and toxicity and e-wastes are non-biodegradable resulting in its cumulative increase over time. Changes in technology and unrestricted regional movement of electrical devices have facilitated the generation of more e-wastes leading to high levels of air, soil and water pollution. To address these challenges, biodegradable organic components such as chitosan have been used to replace their inorganic counterparts for optoelectronic device applications. However, in-depth knowledge on how such materials can be used to tune the optical properties of their hybrid semiconductors is unrivaled. Thus, systematic studies of the interplay between the preparation methods and optical band gap and Urbach energy of such organic components are vital. This study has thus been dedicated to map out the effect of acid concentrations during chitosan extraction on the corresponding optical band gap and Urbach energy with a view to improving its applications in optoelectronic devices. The, 1.0 to 2.5 molar hydrochloric acid (HCl) was used for 12 hours at room temperature during demineralization and 2.0 molar sodium hydroxide (NaOH) during deprotonation processes. The absorbance spectrum of the samples was collected by UV-Vis spectrophotometer and band gap energies were analyzed by performing Tauc’s plot. This study revealed that the energy band gap of chitosan extracted from 1 M HCl, 1.5 M HCl, 2.0 M HCl and 2.5 M HCl were 3.72 eV, 3.50 eV, 3.45 eV and 3.36 eV respectively. Furthermore, the Urbach energy of chitosan extracted from 1 M HCl, 1.5 M HCl, 2.0 M HCl and 2.5 M HCl were 0.60496 eV, 0.5292 eV, 4724 eV and 0.2257 eV, respectively.
Reid A. Patterson, Christopher P. Kabb, David M. Nickerson, Eugene Pashkovski
Advances in Chemical Engineering and Science, Volume 12, pp 65-86; https://doi.org/10.4236/aces.2022.122006

Abstract:
Viscosity index (VI) and shear stability index (SSI) are standard methods used in the lubricant industry to determine temperature-viscosity dependency and resistance to product degradation, respectively. A variety of oil-soluble polymers, including poly(alkyl methacrylates) (PAMAs) are routinely used to control these properties in fully-formulated liquid lubricants. In this report, we use reversible addition-fragmentation chain transfer (RAFT) polymerization to precisely target identical degrees of polymerization in a family of PAMAs with varying lauryl, hexyl, butyl, ethyl, and methyl groups. Then, expanding on previous methodology reported in the literature, we establish structure property relationships for these PAMAs, specifically looking at how intrinsic viscosity [η] and Martin interaction parameters KM relate to VI and SSI characteristics. While the intrinsic viscosity [η] is associated with the volume of macromolecules at infinite dilution, the parameter KM reflects the hydrodynamic interactions of polymer chains at actual polymer concentrations in lubricating oils. In this paper, we show that the dependence of VI on the non-dimensional concentration c/c* (or c[η]) can be presented in a form of master curve with shift factors proportional to KM that decreases with increasing size of alkyl groups. This finding implies that even in the dilute regime, the coil-expansion theory used to explain the effect of macromolecules on VI should be complemented with the idea of hydrodynamic interactions between polymer molecules that can be controlled by the choice of alkyl chains in the family of PAMAs.
Sabar Simanungkalit, Mingming Zhu, Gia Hung Pham, Zhezi Zhang, Dongke Zhang
Advances in Chemical Engineering and Science, Volume 12, pp 40-53; https://doi.org/10.4236/aces.2022.121004

Abstract:
A series of mesoporous alumina (MA) supported cobalt (Co/MA) catalysts with MA isomorphically substituted by zirconium (Zr) were synthesised and evaluated for their performance in the Fischer-Tropsch synthesis. The Zr/(Zr + Al) atomic ratios varied from 1% - 15%. A zirconium-impregnated Co/MA catalyst prepared by wet impregnation with a Zr/(Zr + Al) atomic ratio of 5% was also evaluated to examine Zr incorporation’s effect method. The catalysts synthesised were characterised using N2 adsorption-desorption, X-ray Powder Diffraction (XRD), Transmission Electron Microscopy (TEM), and X-Ray Photoelectron Spectroscopy (XPS). It was found that Zr4+ ions were incorporated into the framework of MA and kept intact up to a Zr/(Zr + Al) atomic ratio of 5%. The cobalt dispersion and reducibility were improved as the Zr/(Zr + Al) atomic ratio increased to 50%. The performance of these catalysts for Fischer-Tropsch synthesis was evaluated using a fixed bed reactor at temperature and pressure of 493 K and 20 bar, respectively. The feed syngas had an H2/CO ratio of 2, diluted with 10% Ar. For isomorphically Zr-substituted Co/MA, the CO conversion and selectivity of diesel (C10 - C20) increased first and then decreased with increasing the Zr/(Zr + Al) atomic ratio. The maximum 38.9% CO conversion and 34.6% diesel (C10 - C20) selectivity were obtained at Zr/(Zr + Al) atomic ratio of 5%. The isomorphic substitution method was better than the wet impregnation method in CO conversion and diesel selectivity.
Adil Koç
Advances in Chemical Engineering and Science, Volume 12, pp 96-113; https://doi.org/10.4236/aces.2022.122008

Abstract:
In this study, the convertibility of disposable plastic waste injectors made of HDPE and PP plastics into valuable chemical products by thermal pyrolysis was investigated. While PP plastic wastes were decomposed in the temperature range of 400°C - 445°C, HDPE plastic wastes were decomposed in the higher temperature range (430°C - 475°C). Although the physical appearance of the liquid products obtained in the thermal decomposition of PP plastic wastes are lighter in color and fluid, it has been observed that the liquid decomposition products of HDPE plastic wastes have a more dense and viscous structure. By using the first-order kinetic model, kinetic expressions for both plastic wastes were derived, reaction rate constants, k, and activation energy, Eact, and thermodynamic quantities such as reaction enthalpy, △H≠, reaction entropy, △S≠ ve and Gibbs free energy, △G≠ were calculated. In the thermal pyrolysis of PP and HDPE plastic wastes, Eact, △H≠, △G≠, △S≠ values are 162.30 kJ/mol, 156.52 kJ/mol, 219.50 kJ/mol, -87.71 J/molK, and 201.80 kJ/mol, 195.77 kJ/mol, and 229.14 kJ/mol, -46.48 J/molK, respectively. These thermodynamic quantities calculated for both plastic wastes show that the pyrolytic decomposition studies carried out in an inert gas atmosphere have endothermic reaction behavior.
Meselu Eskezia Ayalew, Thevabakthi Siluvai Muthu Arul Jeevan
Advances in Chemical Engineering and Science, Volume 12, pp 131-144; https://doi.org/10.4236/aces.2022.123010

Abstract:
Sustainability is the ability to nurture or support a process for a long time without compromising the needs of future generations. Rather, sustainable chemistry is a term that refers to the production of chemical products and processes that reduce or eliminate the use and production of hazardous substances. Green chemistry creates alternative technologies that are safer for human health and the environment to prevent further damage to human health and the environment, such as reducing the release of hazardous chemicals into the air, leading to reduced lung damage. Although sustainable and environmentally friendly technologies have evolved in other areas of science, their use in redox reactions and industry is still in its early stages. The current review aims to highlight the need for green chemistry as a sustainable chemistry and its principles and its application to produce environmentally friendly industrial products and to reduce or stop the production of harmful intermediates and products during its synthesis process.
Mostafa Elaghoury, Ali Alarbah, Ezeddin Shirif, Na Jia
Advances in Chemical Engineering and Science, Volume 12, pp 145-162; https://doi.org/10.4236/aces.2022.123011

Abstract:
Given the rise in oil productivity from conventional and unconventional resources in Canada using Enhanced Oil Recovery (EOR), the need to understand and characterize these techniques, for the purpose of recovery optimization, has taken a prominent role in resource management. Chemical flooding has proved to be one of the most efficient EOR techniques. This study investigated the potential of employing Ionic Liquids (ILs) as alternative chemical agents for improving oil recovery. There is very little attention paid to employing this technique as well as few experimental and simulation studies. Consequently, very limited data are available. Since pilot and field studies are relatively expensive and time consuming, a numerical simulation study using CMG-STARS simulator was utilized to explore the efficiency of employing 1-Ethyl-3-Methyl-Imidazolium Acetate ([EMIM][Ac]) and 1-Benzyl-3-meth- limidazolium chloride ([BenzMIM][Cl]) with respect to improving medium oil recovery. Eight different lab-scale sandpack flooding experiments were selected to develop a numerical model to obtain the history matching of the experimental flooding results using CMG-CMOST. We observed that the main challenge was tuning the relative permeability curves to achieve a successful match for the oil recovery factor. Finally, a sensitivity study was performed to examine the effect of the chemical injection rate, the chemical concentration, the slug size, and the initiation time on oil recovery. The results showed a noticeable increase in the oil RF when injecting IL compared to conventional waterflooding.
Andrew Odeh, Redemption Edegbe, Eghe Oyedoh
Advances in Chemical Engineering and Science, Volume 12, pp 13-25; https://doi.org/10.4236/aces.2022.121002

Abstract:
Drilling mud is a key component in drilling operations and in accessing oil and gas reservoirs. Bentonite is applied as a viscosifier, fluid loss control agent, and as a weighting material in water-based drilling mud. The type of bentonite used in drilling mud formulation is sodium bentonite due to its high dispersion properties and high swelling capacity. Nigeria has a huge bentonite clay deposit resources which can be evaluated and enhanced in order to be utilized as drilling mud. However, bentonite clay from different parts of Nigeria was investigated and found to be calcium bentonite which is not suitable for drilling mud, because it has low swelling capacity and poor rheological properties. In this study, local bentonite obtained from Afuze, Edo state was used to formulate different samples of drilling mud with each treated using thermo-chemical beneficiation process with sodium carbonate and cassava starch, and then undergo characterization to identify the changes in physical properties and finally, draw comparison with API values for standard drilling mud. The results obtained from this study indicates that, the flow and rheological properties of the beneficiated drilling mud developed through thermo-chemical treatment, showed significant improvement compared to the untreated mud. Therefore, pure calcium bentonite from natural deposits in Nigeria can be modified to sodium bentonite and sufficiently used in drilling mud formulation.
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