Browsing by Author "Emanuel X. Ricky"
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Item A comprehensive review on CO2 thickeners for CO2 mobility control in enhanced oil recovery: Recent advances and future outlook(Journal of Industrial and Engineering Chemistry, 2023-06-16) Emanuel X. Ricky; Grant Charles Mwakipunda; Edwin E. Nyakilla; Naswibu A. Kasimu; Chao Wang; Xingguang XuCarbon dioxide (CO2) has been utilized to recover the residual oil from the geological reservoirs through enhanced oil recovery (EOR) methods for over 50 years. Despite its long history of success as an EOR technique, CO2 flooding recovers only about 20–40% of the original oil in place (OOIP) from the geological reservoirs. The small amount of oil recovered by CO2 flooding is associated with the low viscosity of CO2 injected into the reservoir, resulting in CO2 viscous fingering, CO2 gravity override and unfavourable mobility. To address these problems, the CO2 viscosity needs to be enhanced considerably using CO2 thickeners or viscosifiers. Despite more than five decades of intensive research work in formulating and identifying effective CO2 thickeners such as polymers, surfactants, small molecules and nanoparticles; as yet none of these chemicals can be regarded as effective CO2 thickeners for EOR field applications. Thus, CO2 thickener is an interesting research topic for future studies to come up with effective and affordable CO2 thickeners for EOR field applications. This article presents the recent developments in CO2 thickening technologies in EOR. Furthermore, the CO2 thickening mechanisms, screening criteria, field scale applications, challenges and future research directions on CO2 thickeners are evaluated.Item Potential of Kaolin Clay on Formulation of Water Based Drilling Mud Reinforced with Biopolymer, Surfactant, and Limestone(College of Natural and Applied Sciences, University of Dar es Salaam, 2023-03-31) Paul M. Omary; Emanuel X. Ricky; Naswibu A. Kasimu; Makungu M. Madirisha; Kessy F. Kilulya; Esther H. J. LugwishaDrilling the wellbore into subsurface formations is the earliest stage in the life of a well that requires a suitable drilling fluid with good rheological and filtration control characteristics to achieve a successful drilling operation. This paper reports on the formulation of water-based drilling mud using kaolin clay reinforced with biopolymer, surfactant, and limestone from Tanzania. The raw materials used for the formulation were characterized using XRD, XRF, FTIR, and TGA techniques. The rheological properties, filtration loss, pH, and density of the formulated mud were measured using a viscometer, filter press, pH meter, and mud balance, respectively. The XRD results revealed kaolinite and quartz as the main minerals in all kaolin clay samples which were in agreement with the FTIR findings. The mineralogical composition of the kaolin was observed to vary with the mining sites and influenced the rheological and filtration control characteristics of the mud. The beneficiated drilling mud showed better rheological and filtration control characteristics than the commercially available bentonite mud in Dar es Salaam market and was comparable with the API standards. These results, therefore, are not only new but rather important and novel information on the potential of kaolin clay for the formulation of water based drilling mud.Item Thermochemical conversion of underutilized lignocellulosic waste to syngas: Supercritical water gasification for value addition to corncob and sisal waste(African Journals Online, 2023-12-25) Esther H. Lugwisha; Datius S. Revocatus; Naswibu A. Kasimu; Emanuel X. Ricky; Makungu M. Madirisha; Lilian D. Kaale; Noah M. Puline; Kessy F. KilulyaIn the context of escalating global energy demands and environmental concerns associated with fossil fuels, this paper reports the conversion of underutilized agricultural residues in Tanzania, namely corncob and sisal waste, into syngas as sustainable biomass alternatives for energy production. Employing supercritical water gasification, the study evaluated the potential of corncob and sisal waste for syngas generation. Proximate analysis showed corncob as more suitable for energy conversion due to its lower moisture content (11.5%) and higher volatile matter (74.9%), compared to the higher moisture (14.9%) and ash content (17.2%) of sisal waste. However, the elemental analysis underscores both materials' feasibility for syngas production, with corncob and sisal waste showing substantial carbon and hydrogen contents, which are crucial for syngas. Despite the slight energy advantage of corncob indicated by its higher heating values (HHV: 25.44 MJ/kg, LHV: 24.40 MJ/kg) over sisal waste (HHV: 24.87 MJ/kg, LHV: 23.86 MJ/kg), reaction kinetics and syngas composition analysis suggested that both residues are viable feedstocks. Reaction kinetics analysis revealed temperature dependence in the conversion process, with higher temperatures favoring hydrogen production but increasing CO2 emissions, underscoring the need for a balanced approach in syngas production. The syngas produced composes of H2, CO, CH4, CO2, and light hydrocarbon gases. Moreover, the H2/CO of the syngas gas was less than 1, suggesting that this syngas would be suitable for oxo-synthesis, aligning with existing literature. Regression analysis highlights temperature as the most influential factor on Total Syngas Yield, with significant R-square values (0.992 for corncob and 0.944 for sisal waste). However, a paired sample T-test indicated no significant yield difference between corncob and sisal waste (t-value = -0.518, p-value = 0.626). These values implied that both feedstocks are equally effective in syngas production under the examined conditions. This observation suggested that feedstock selection can be flexible based on other factors such as availability and environmental impact. The findings contribute new insights into biomass-to-energy conversion, emphasizing the viability of agricultural residues as sustainable energy sources. It informs feedstock selection, balancing environmental impact and cost factors, and advocates for a shift towards a more sustainable, circular energy economy.