Browsing by Author "Clarke, Matthew Alexander"
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- ItemOpen AccessAn Integrated Deep Learning Model with Genetic Algorithm (GA) for Optimal Syngas Production Using Dry Reforming of Methane (DRM)(2024-01-17) Zarabian, Maryam; Olatunji Fapojuwo, Abraham; Souza, Roberto; Clarke, Matthew AlexanderThe dry reforming of methane is a chemical process transforming two primary sources of greenhouse gases, i.e., carbon dioxide (CO2) and methane (CH4), into syngas, a versatile precursor in the industry, which has gained significant attention over the past decades. Nonetheless, commercial development of this eco-friendly process faces barriers such as catalyst deactivation and high energy demand. Artificial intelligence (AI), specifically deep learning, accelerates the development of this process by providing advanced analytics. However, deep learning requires substantial training samples and collecting data on a bench scale encounters cost and physical constraints. This study fills this research gap by employing a pretraining approach, which is invaluable for small datasets. It introduces a software sensor for regression (SSR) powered by deep learning to estimate the quality parameters of the process. Moreover, combining the SSR with a genetic algorithm offers a prescriptive analysis, suggesting optimal thermodynamic parameters to improve the process efficiency.
- ItemOpen AccessCatalytic Hydroprocessing of Tire Pyrolysis Oil Distillates(2022-12-16) Marti, Javier; Pereira-Almao, Pedro R.; De la Hoz Siegler, Hector; Clarke, Matthew AlexanderEnergy demand is still in the rising, as well as the environmental concerns related to the use of fossil fuels to meet it. Hence, the transition to alternative and renewable energy sources has become a priority. The production of tire pyrolysis oil (TPO) to eliminate waste tires and produce atmospheric distillates (IBP343°C) has great potential to reduce the amount of waste material and contribute to the energy transition. This work aimed to study the TPO atmospheric distillates upgrading capabilities using the hydrotreating (HDT) process and a new proprietary group of catalysts. First, catalyst Mo2C/Zeolite (P-1) was tested on a synthetic feedstock composed of model molecules emulating TPO atmospheric distillates. Results proved that the highest conversion of nitrogen and sulfur was achieved at 350°C and 0.3 h-1. Additionally, high conversion selectivity of the nitrogenated compounds was observed based on 100 % conversion of the quinoline model molecule. The previous experiment was followed by testing catalyst P-1 and another catalyst Mo2C/γ-Al2O3 (M-3) using a TPO naphtha/kero fraction (IBP-280°C). This test demonstrated that the acidity of the support was key to achieving higher levels of upgrading, nevertheless, it needed to be balanced with a higher hydrogenating function. Later, another set of experiments was performed using a TPO atmospheric distillates (IBP-343°C) fraction and catalysts M-3, P-2 and P-3, the last two with increasing hydrogenation functions. Results showed that catalyst P-3 reached sulfur and nitrogen levels conversion of 90% and 89%, respectively. Additionally, a study of the HDT products obtained in the last experiment was performed based on the distillation of the product into heavy naphtha (IBP-220°C) and diesel (220-343°C). Characterizing these cuts indicated that aromatic and polar compounds initially present in the heavy naphtha are easier to hydrogenate than those in the diesel fraction. Additionally, partial hydrogenation was observed in both cases due to the reduction of polyaromatic compounds and an increase in the tetralin family. Finally, a study on the reaction severity revealed that temperatures of 350°C, weight hourly space velocity of 0.1 h-1, pressure of 1,500 psig and Vol. H2/Oil of 1,200 are preferred for higher hydrogenation.
- ItemOpen AccessDetermination of the intrinsic kinetics of gas hydrate decomposition by particle-size analysis(2000) Clarke, Matthew Alexander; Bishnoi, Prithwi R.
- ItemOpen AccessMeasuring and Modelling of the Thermodynamic Equilibrium Conditions for the Formation of TBAB and TBAC Semi-Clathrates formed in the Presence of Xenon and Argon(2015-05-01) Garcia Mendoza, Marlon Ilich; Clarke, Matthew AlexanderSemiclathrates are crystalline compounds similar in nature to gas hydrates. Like gas hydrates, semiclathrates can trap small gas molecules inside a molecular framework of water molecules. Quaternary ammonium salts (QAS) semiclathrates hydrates, such as tetra-n-butyl ammonium bromide (TBAB) and tetra-n-butyl ammonium chloride (TBAC), are ionic compounds that have a stabilizing effect on the framework of water molecules. TBAB and TBAC semiclathrates formed in the presence of a gas can form at much milder conditions than gas hydrates. Thus, there has been much interest, in recent years, on the possible use of TBAB and TBAC semiclathrates in the storage and separation of gases. To date, the majority of research in the area has been directed towards experimental studies and only a handful of studies have attempted to model the equilibrium conditions of semi-clathrate formation. The present study aims to measure and correlate equilibrium dissociation conditions for semiclathrates formed from aqueous solutions of TBAB and TBAC, in combination with argon and xenon. In the experimental part of this study, a constant-volume reactor was used for measuring the solid–vapor–liquid equilibrium conditions of semiclathrates formed in aqueous solutions of TBAB and TBAC. The TBAB and TBAC semiclathrates were formed from pure argon and pure xenon. The experimental temperatures ranged from (284 to 303) K, the experimental pressures ranged from (266 to 6114) kPa, the weight fraction of TBAB ranged from wTBAB = (0.05 to 0.20), and the weight fraction of TBAC ranged from wTBAC = (0.05 to 0.20). As expected, at a given temperature, the pressure required to form TBAB and TBAC semiclathrates with argon and with xenon was much lower than the pressure that are required to form pure gas hydrates. From the equilibrium data, the enthalpy of formation was estimated to be between (133 and 188) kJ•mol–1 for semiclathrates formed from argon and (55 and 127) kJ•mol–1 for semiclathrates formed from xenon. For modeling the experimental data obtained in the present study, the PSRK equation of state is used to describe the vapour phase, the LIFAC activity coefficient model is used to describe the aqueous phase and the van der Waals and Platteeuw theory combined with the model of Paricaud was employed to describe the solid semiclathrate phase. The new model differs from previous modeling efforts in that it does not neglect the solubility of the gas in the aqueous phase or the presence of water in the vapour phase. Rather, the solubility of the gas and molar fraction of water in vapour phase are computed from a flash calculation. The new model also computes the Langmuir constants from the Kihara potential rather than from an empirical correlation. The model is capable of describing the solid-liquid equilibrium for the semiclathrate in the absence of gas molecules. The new modeling approach is applied to TBAB and TBAC semiclathrates that are formed from xenon and argon. For both gases, new Kihara potential parameters were regressed from the experimental data. Further testing of the new modelling approach was conducted by correlating available data for TBAB/TBAC semiclathrates formed in the presence of pure methane (CH4), carbon dioxide (CO2), nitrogen (N2), and hydrogen (H2). It was found that the new approach was able to correlate the experimental data to a high degree of accuracy with fewer adjustable parameters for all but one of the existing modelling attempts.
- ItemOpen AccessModeling of Low Salinity Waterflooding in Petroleum Reservoirs(2020-09-29) Nikpoor, Mohammad Hossain; Chen, Zhangxing; Nghiem, Long X.; Clarke, Matthew Alexander; Hejazi, Hossein; Wang, Xin; Gildin, EduardoOil production from reservoirs is traditionally categorized into three phases: primary, secondary, and tertiary (also known as Enhanced Oil Recovery, EOR). Per the US Department of Energy, utilizing primary and secondary methods of production can leave up to 75% of the oil in place. The way to further increase oil production is through EOR. Although more expensive to employ in a field, EOR can increase production from a well up to 75% recovery.Low Salinity Waterflooding (LSW) is a promising technique for improving oil recovery in petroleum reservoirs because of its relatively simple implementation, lower cost, and fewer environmental problems associated with this process compared to other EOR methods. Worldwide companies (including BP, Shell, Statoil, and Saudi Aramco) are involved in the research and development of this technique.Most studies on the subject have focused on the experimental and some on the theoretical aspects, with varying, sometimes contradictory conclusions. However, the optimum conditions that improve oil recovery by LSW flooding are still uncertain due to the lack of understanding of the underlying fluid-rock interaction mechanisms. There has been much modeling research on the modeling of the process in sandstone reservoirs in an attempt to understand these mechanisms and identify the main ones that maximize the recovery in order to design successful field applications. Most of these studies have concluded that the macroscopic mechanism for improved recovery in LSW is wettability alteration due to different microscopic rock-fluid and fluid-fluid interactions when low salinity water is introduced to the system. A few investigations have focused on the possibility of fine migration and its potential effect during LSW.In this thesis, I will review and model the mechanisms in oil reservoirs and focus on fine migration and its similarity to the polymer flooding and asphaltene flow and precipitation whose models exist in commercial reservoir simulators. Parts of this research will be integrated into a reservoir simulator to test and validate the ideas. At the end, I will extend my work into hybrid LSW processes and their optimization.
- ItemOpen AccessProbing Nucleation Mechanisms of Gas Hydrates via Molecular Simulations(2023-11-02) Wang, Lei; Kusalik, Peter G; Marriott, Robtert A; Tieleman, Peter DP; Clarke, Matthew Alexander; Patey, GrenfellGas hydrates are ice-like solids where guest species can be encapsulated in water cages. Gas hydrates have received considerable attention because of the vast natural methane hydrates and various promising hydrate-based technologies. Relevant to the applications, a fundamental molecular-level understanding of nucleation behavior and mechanisms is necessary to support ongoing developments associated with gas hydrates. With the primary goal to provide significant insights into the mechanistic details of gas hydrate formation at the molecular level, this thesis investigates the behavior of gas hydrate nucleation and growth using Molecular Dynamic (MD) simulations along with Markov State Models (MSMs). The investigation of the nucleation behavior of mixed CH4/H2S hydrates within bulk aqueous solutions reveals the roles of different guest species in the hydrate formation process and the impacts of guest compositions, temperature, and different physical setups on the hydrate nucleation behavior. CH4 species has been consistently observed enriched in the hydrate phase relative to the aqueous solution, while increasing H2S composition can significantly enhance the rate of nucleation and growth of the hydrate through enhancement of the solubility of guests in solution. The investigation of the nucleation mechanisms of gas hydrates in water nanodroplets with pure-guest and mixed-guest species reveals key factors affecting hydrate nucleation behavior, including guest species, guest compositions, size of the nanodroplet, and temperature. The effects of temperature and the size of the water nanodroplet on the location of the initial hydrate nucleus have been explored. Utilizing water nanodroplet systems, the possible origins of the different effects of temperature control schemes on the behavior of hydrate formation have been addressed. It is found that the finite size of the surroundings is the origin of the influence of the temperature control schemes on the hydrate nucleation rates. Novel structural analyses, based on applying MSMs to data from gas hydrate simulations, have been used to identify and characterize a general transition network describing hydrate formation. This transition network of cage formation and the corresponding thermodynamic behavior confirm and validate that hydrate nucleation is essentially an ordering-in-stages process, where the early-stage behavior leading to a hydrate nucleus is dominated by entropic aspects.