-
Research Article
Numerical Modeling and Performance Evaluation of a New Biogas Purification System
Tchatcha Abanda Ghratien*,
Gnepie Takam Nicolas Wilfred,
Edoun Marcel,
Tientcheu Nsiewe Maxwell,
Kuitche Alexis
Issue:
Volume 9, Issue 1, June 2025
Pages:
1-8
Received:
24 February 2025
Accepted:
6 March 2025
Published:
21 March 2025
Abstract: In order to meet the challenges posed by dependence on fossil fuels, it is essential to develop an energy alternative based on renewable sources. Among alternative energy solutions, biogas occupies a prime position. However, before biogas can be used, it must be purified, which involves removing the carbon dioxide (CO2) and recovering the methane (CH4), thereby increasing the calorific value of the methane. The most innovative purification solution is cryogenics. Our aim in this work is to use cryogenics to purify biogas by liquefying the carbon dioxide it contains. To achieve this, we have designed and dimensioned the various components of a cryogenic purification unit for biogas production. Using the incremental method based on heat conservation equations, we simulated this purification process on the Aspen plus calculation code. Using the ADMI calculation code, we modeled the model equations to visualize the behavior of the various parameters to be controlled. The temperature, pressure and mass flow profiles affecting the desublimation of carbon dioxide were obtained. Furthermore, the sizing results show that a 450 W compressor and a condenser with a capacity of 2.5 kg are required. The temperature and pressure of the biomethane and carbon dioxide at the condenser outlet are -130°C and 15 bars. Simulations show curves for variations in temperature, pressure, rate of bio-methane recovery and carbon dioxide evacuation. They show that it is possible to produce biomethane with a purity of 96%, with a very negligible amount of carbon dioxide and a high lower calorific value (LCV) than raw biogas (9.83 kWh/m3 higher than 6 kWh/m3), a significant value in energy terms, showing that this biomethane could be used for a variety of purposes.
Abstract: In order to meet the challenges posed by dependence on fossil fuels, it is essential to develop an energy alternative based on renewable sources. Among alternative energy solutions, biogas occupies a prime position. However, before biogas can be used, it must be purified, which involves removing the carbon dioxide (CO2) and recovering the methane (...
Show More
-
Research Article
An Aircraft Hydraulic Brake System Model Analysis Using LMS Amesim Tool
Issue:
Volume 9, Issue 1, June 2025
Pages:
9-36
Received:
15 February 2025
Accepted:
28 February 2025
Published:
28 March 2025
Abstract: Developing a new system architecture from scratch and validating its functional behavior is a time-consuming and complex task. Instead, an analogy-based design approach allows for the development of new systems derived from existing designs, reducing both development time and cost. This study presents the design and simulation of an aircraft hydraulic brake system using the LMS Amesim software tool. The simulation results demonstrate that the proposed brake system effectively meets aircraft hydraulic system design requirements, including MIL-H-5440H standards. The hydraulic pump achieved a stable system pressure of 209 bar, with peak pressure reaching 272 bar during high-demand conditions. The brake accumulator successfully charged to 100 bar within 6.5 seconds, storing 310 cc of oil and compressing 355 cc of nitrogen gas. The pressure reducing valve (PRV) effectively regulated system pressure from 210 bar to 100 bar for braking applications. The brake actuators responded within 0.75 seconds, delivering the required force to counteract wheel torque, while the shuttle valve successfully managed the transition between normal and emergency braking conditions. The return line maintained a stable backpressure of approximately 4 bar, preventing fluid surges. Overall, the simulation results validate the feasibility of the proposed hydraulic brake system, demonstrating compliance with military hydraulic standards and confirming its suitability for aircraft applications. Future improvements, such as antiskid integration, optimized flow control, and further system refinement, are discussed to enhance performance.
Abstract: Developing a new system architecture from scratch and validating its functional behavior is a time-consuming and complex task. Instead, an analogy-based design approach allows for the development of new systems derived from existing designs, reducing both development time and cost. This study presents the design and simulation of an aircraft hydrau...
Show More
-
Research Article
Estimation and Optimization of Specific Heat of TIG Weld of Mild Steel (s275) Using Response Surface Methodology
Augustine Oghenekevwe Igbinake*
Issue:
Volume 9, Issue 1, June 2025
Pages:
37-44
Received:
12 April 2025
Accepted:
27 April 2025
Published:
4 June 2025
DOI:
10.11648/j.ae.20250901.13
Downloads:
Views:
Abstract: Specific heat, an intrinsic thermal property, represents the amount of heat energy required to raise the temperature of a substance by one degree Celsius. Accurate estimation of specific heat in welded metals is crucial for understanding thermal behavior during and after welding processes, especially in applications where temperature control and energy efficiency are essential. This study focuses on the prediction and optimization of the specific heat of mild steel weldments using Response Surface Methodology (RSM), a statistical technique for modeling and analyzing the effects of multiple variables. A total of 100 welded mild steel specimens, each measuring 60 mm × 40 mm × 10 mm, were prepared through controlled Tungsten Inert Gas (TIG) welding operations. During the experiments, key process parameters - welding current, arc voltage, and shielding gas flow rate - were systematically varied to observe their effect on specific heat. The experimental data collected were analyzed using Design Expert 13 software, enabling statistical modeling, regression analysis, and optimization. A second-order quadratic model was developed to describe the relationship between specific heat and the input parameters. The optimal parameter combination was determined to be 180 A, 19 V, and 13 L/min, resulting in a predicted specific heat value of 445.106 J/kg°C. The developed model provides a useful predictive tool for future thermal analysis of welded structures.
Abstract: Specific heat, an intrinsic thermal property, represents the amount of heat energy required to raise the temperature of a substance by one degree Celsius. Accurate estimation of specific heat in welded metals is crucial for understanding thermal behavior during and after welding processes, especially in applications where temperature control and en...
Show More
-
Review Article
The Impacts of Ethiopia's Green Legacy on Soil Conservation and on Climate Change: A Review
Zalalem Tamiru Bekele*,
Lata Hailu
Issue:
Volume 9, Issue 1, June 2025
Pages:
45-49
Received:
21 December 2024
Accepted:
27 April 2025
Published:
18 June 2025
DOI:
10.11648/j.ae.20250901.14
Downloads:
Views:
Abstract: The Green Legacy initiative in Ethiopia aims to promote a healthy environment by restoring ecosystems, mitigating climate change, and fostering environmental awareness. It involves tree planting, carbon sequestration, biodiversity conservation, soil conservation, community engagement, and climate education. A mixed research method found positive effects on the environment, and researchers recommend policymakers and the government consider the six parameters of the initiative for evidence-based decision-making for sustainable environmental management in Ethiopia. Ethiopia is home to some of the world's most biodiversity ecosystems, but its environment is also under threat from climate change, deforestation, and other human activities. To protect its unique biodiversity and ensure a healthy environment for its people, Ethiopia must take bold steps to create a green legacy. This includes reducing greenhouse gas emissions, investing in renewable energy sources like solar, wind, and hydropower, implementing energy efficiency initiatives, investing in conservation and sustainable land management, and investing in environmental education and awareness. By investing in renewable energy, conservation, and environmental education, Ethiopia can reduce emissions, protect its biodiversity, and create a healthier environment for its people. This green legacy will ensure that Ethiopia's unique ecosystems are preserved and that citizens can enjoy a healthy environment for generations to come.
Abstract: The Green Legacy initiative in Ethiopia aims to promote a healthy environment by restoring ecosystems, mitigating climate change, and fostering environmental awareness. It involves tree planting, carbon sequestration, biodiversity conservation, soil conservation, community engagement, and climate education. A mixed research method found positive ef...
Show More
