Browsing by Author "Monge, Emmanuel"

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Analysis of carbon dioxide reservoir performance and optimization strategies: a case study of a carbon dioxide plant
(Springer, 2025-01-29) Monge, Emmanuel; Kichonge, Baraka
This study aimed at developing an empirical model for estimating and analyzing CO2 reservoir performance. This was achieved by using decline curve analysis (DCA) to determine an accurate empirical decline model for reservoir performance prediction and optimal producing, i.e., time at which the plant recovery build-up (RBU) efficiency has declined to an approximate value of 44.5%. MATLAB R2013b was used for calculating raw gas density whereas Ms Excel 2007 was used in plotting and performing all calculations. Through an examination of real production data, a harmonic decline model with an Arps’ decline constant (d) of 1.0 and a nominal decline rate of approximately 0.035572337/year was identified as the most suitable for characterizing reservoir performance. The study identifies the year 2048 as an optimal opportunity for implementing production optimization strategies to maximize returns while ensuring efficient resource recovery. Acknowledging the limitations of DCA, the study recommends exploring alternative forecasting models such as type curve analysis (TCA), material balance equation (MBE), and well simulation techniques to mitigate uncertainties in reservoir performance prediction. In addition, the study proposes a 5-year model verification and improvement program to refine reservoir descriptions and enhance data acquisition practices, aiming to optimize production efficiency and minimize uncertainties in CO2 reservoir operations.
Techno‐Economic Evaluation of Synthetic and Natural Antioxidants Used for Enhancing Oxidation Stability of Biodiesel
(sci, 2025-01-07) Kahimbi, Henry; Monge, Emmanuel; Kichonge, Baraka; Kivevele, Thomas
The oxidation stability of biodiesel is a critical factor affecting its storage and performance, necessitating the use of antioxidants to enhance its shelf life and reliability. Both natural and synthetic antioxidants have proven effective in improving the oxidation stability of biodiesel, with numerous studies demonstrating their ability to extend the induction period and delay oxidative degradation. However, while the technical efficacy of these antioxidants is well‐documented, the techno‐economic analysis that evaluates the cost‐effectiveness of using natural versus synthetic antioxidants remains unexplored. This creates uncertainty in selecting the most sustainable and economically viable antioxidant option. This study aimed to conduct a techno‐economic analysis comparing the cost‐effectiveness of synthetic and natural antioxidants in stabilizing biodiesel. The study evaluated synthetic antioxidants, specifically hydrogenated methoxy eugenol, and natural antioxidants derived from the methanolic extract of wild loquat plants, along with a comparison to commonly used synthetic antioxidants. Comprehensive simulations and modeling were conducted using Aspen Plus® V10 commercial simulation software in a block‐wise manner. The technical performance was assessed by considering the quantities and qualities of biodiesel, glycerol, and antioxidants. The synthetic antioxidant processes resulted in negative net present values and longer payback periods of 11.7 to 17.8 years, while natural antioxidants showed shorter payback periods ranging from 3.8 to 12 years. Natural antioxidants, particularly those extracted from clove wastes and wild loquat plant parts, demonstrated superior techno‐economic performance with the lowest operating and raw materials costs, shortest payback period, highest internal rate of return (IRR), and best profitability. Therefore, natural antioxidants are the most economically viable option for biodiesel stabilization, outperforming synthetic antioxidants in terms of operating costs, payback period, IRR, and profitability.