Cleaner Engineering and Technology最新文献

Sugarcane juice (ScJ) is a natural and renewable reservoir of sucrose, which makes it a sustainable carbon source for fermentative production of microbial products. This study encompasses the production of an oleaginous yeast (OY), Rhodosporidium kratochvilovae MTCC247 on ScJ-based nutrient medium and optimization of the fermentation process. Initially, ScJ was clarified by cloud point extraction (CPE) of polyphenols using Box Behnken Design resulting in 90.88 % reduction in polyphenols. After individual optimization of fermentation parameters such as initial pH, incubation temperature, agitation speed, aeration ratio and inoculum size, suitability of clarified ScJ as a sole carbon source was established by incorporating it in a fermentation medium to produce OY. Using a rotatable central composite design, optimal concentrations of medium components were determined to achieve maximum biomass production of 23.13 ± 1.72 g/L and maximum lipid production of 7.15 ± 0.377 g/L. The dynamics of fatty acid pool in OY were studied throughout fermentation. For efficient lipid extraction, a combination of mechanical method (high-speed homogenization) and chemical methods (acid treatment) could recover 93.14 ± 12 % lipids. Thus, this study illustrates the potential of clarified ScJ as a sustainable carbon source in bioprocessing of lipids from OY.

The pressing need to significantly reduce global CO₂ emissions requires the decarbonization of the shipping industry. Currently, shipping relies on fossil fuels with a shift from heavy oil to liquefied natural gas. The main engine is the primary energy user onboard vessels, and its exhaust is the main CO₂ emission source. A potential path to reduce emissions onboard vessels is the capture, compression, and storage of CO₂ from the exhaust gases. This requires effective integration across the engine, the capture technology, the CO₂ compression, cooling, and storage. The integration of four alternative capture technology options is conceptually explored and assessed: chemical absorption, membranes, temperature swing adsorption, and cryogenic distillation. Integration schemes are developed for each of the four technologies that achieve carbon capture, compression, and storage driven by the exhaust gas waste heat as the only energy source. Heat and power requirements are met through heat integration and heat-to-power conversions using organic Rankine cycles (ORCs). The study was performed on an LNG vessel using LNG fuel in its main engine. Thermal capture technologies (absorption and adsorption) are observed to significantly outperform their alternatives (membranes and cryogenic distillation) and capture, compress, and store more than twice the amount of CO₂ emissions from the engine exhaust stream. Finally, the proposed integration schemes resulted in self-sustainable onboard capture systems without combusting additional fuel.

As a densely populated country experiencing rapid economic growth, Bangladesh faces a surging demand for energy. Despite efforts to develop renewable energy sources, coal remains a significant share of the energy mix with a consumption of 2,099,900 tons. However, conventional coal utilization raises environmental concerns like greenhouse gas emissions and other hazardous pollutants. To tackle these issues, viable solutions like clean coal technologies come into play. These encompass high-efficiency low-emission (HELE) power stations, carbon capture utilization and storage (CCUS) systems, integrated gasification combined cycle (IGCC), as well as supercritical and ultra-supercritical steam cycles (S/USC), providing adequate means to reduce the ecological effects tied to coal-powered electricity production. This paper asserts that the strategic adoption of clean coal technologies can play a pivotal role in shaping Bangladesh's sustainable energy future, contingent upon robust policy frameworks, environmental impact and recommend that the government must incentivize HELE, CCUS, and clean coal as well as promote international collaboration. Moreover, modern coal preparation techniques and the future research direction are also discussed in this paper and additionally this study suggests that HELE technologies are more suitable for Bangladesh than other current technologies. These strategies have the potential to yield enhanced economic benefits and offer viable solutions for achieving the clean and efficient conversion of coal resources.

Water pumping systems are crucial for extracting water from deep wells. However, electricity shortages and high fuel prices significantly impact the efficiency and reliability of these systems. Therefore, renewable energy sources have gained more attention as alternatives to fossil fuels. Photovoltaic (PV) energy-based pumping systems, in particular, are becoming popular, especially in rural areas where grid connections are often unavailable. Several factors influence the performance of photovoltaic water pumping systems (PVWPS), including solar irradiance, temperature, system design, maintenance, and pumping load. To ensure optimal performance under these varying conditions, two controllers are crucial. The first controller is the Maximum Power Point Tracking (MPPT) controller, designed to maximize power extraction from the PV panels under varying environmental conditions (in particular, solar radiation and temperature). The second controller regulates the speed and torque of the induction motor (IM) which drives the pump responsible for water extraction. Therefore, to improve the performance of these controllers under different conditions. This review paper first examines widely used soft computing methods, providing a detailed description of each. These methods are then applied to both the MPPT and the IM controllers, offering valuable insights for researchers looking to develop advanced PVWPS control configurations for future applications.

Efficient and sustainable use of biomass resources is crucial to meet the increasing demand for bio-based products and renewable energy. The biomass supply chain, which includes harvesting, collecting, logistics, storage, and pre-treatment, faces challenges due to uncertainties such as market fluctuations, equipment availability, weather conditions, and transportation constraints. These uncertainties often hinder the optimisation of the supply chain. This research work explores the performance of the biomass supply chain by optimizing operations while accounting for these uncertainties. Nigeria is faced with power issues and there are resources to combat the problem through generation of cleaner energy from biomass. Using mathematical modelling, the study evaluates the impact of uncertainty on key performance areas like feedstock supply, inventory management, transportation efficiency, and processing capacity. The research demonstrates the importance of incorporating uncertainty-aware solutions to minimize risks and improve the flexibility of the biomass supply chain. Sensitivity analyses and case studies shows that the proposed probabilistic modelling approach provides valuable insights into system vulnerabilities and effective strategies for optimizing operations under uncertain conditions. The findings highlight the potential of this approach to improve decision making, resource allocation, and promote sustainable practices in the biomass sector. Ultimately, the study contributes to advancing biomass supply chain management, paving the way for a more resilient and efficient use of bioresources.

In the present work, a new configuration of the three-part blade (3-PB) Vertical Axis Wind Turbine (VAWT) is introduced. This new configuration is designed to further improve the aerodynamic performance of the 3-PB VAWT by tilting all three parts of every single blade along its central chord line. An optimization process is conducted to find the best tilt angle of blade parts in order to maximize the average total torque coefficient. The optimization process is applied to reference 3-PB VAWT with the help of a Genetic Algorithm (GA) and Artificial Neural Network (ANN) using the solutions of three-dimensional Reynolds averaged Navier-Stokes (RANS) equations at wind speed of $7$ m/s and tip speed ratios from 0.44 to 1.77. Having analyzed different sets of tilt angles, a configuration with tilt angles of 30°, 31° $\text{,}$ and 30° with respect to part 1, 2, and 3 was detected to be the best choice. The tilted 3-PB VAWT shows promising improvements in most tip speed ratios. Among them, a maximum improvement of 42.99% on the average of the total torque coefficient occurred at tip speed ratio of 0.89.

This research explores a sustainable approach for fabricating high-performance nanodiamond composite (NDC) hard coatings for dry machining. Aiming to address limitations in conventional coatings, such as environmental concerns, restricted film thickness, and compromised performance. The study utilizes Coaxial Arc Plasma Deposition (CAPD), a clean and efficient technique, to deposit thick (10 μm) NDC films directly on WC−Co substrates without chemical etching. Compared to traditional Chemical Vapor Deposition (CVD), CAPD offers significant advantages: lower temperature deposition, faster growth rate, and precise control over film thickness and morphology. The resulting NDC films boast exceptional durability due to their unique nanostructure, diamond nanocrystallites embedded in an amorphous carbon matrix. The addition of Al-interlayers (100–500 nm thickness) optimizes film properties. The optimal interlayer at 100 nm thickness not only mitigates the catalytic effects of Co but also enhances film hardness (50.4–58 GPa), Young's modulus (516–613.75 GPa), and adhesion (13–18.5 N) compared to films without an interlayer. Notably, the 100 nm Al-interlayer triples the deposition rate to 3.3 μm/h, achieving the desired thickness for effective hard coatings. The high density of grain boundaries within the films allows for exceptional stress release, enabling this increased thickness. Furthermore, these grain boundaries and the graphitic phase contribute to the film's superior tribological performance – a low coefficient of friction (0.1) and minimal wear rate (1.5 × 10⁻⁷ mm³/N⋅m) under dry machining conditions. These findings demonstrate the immense potential of CAPD-deposited NDC films as a sustainable alternative for advanced cutting tools, promoting environmental responsibility, economic viability, and energy efficiency.

Increased societal awareness, stakeholder pressure, stringent environmental norms, and the need to sustain in the competitive business market have demanded environment-friendly manufacturing practices from the industrial communities. Sustainable manufacturing (SM) practices have gained widespread attention as they aim to balance economic, environmental, and social activities of organizations. However, still there is a lacuna in understanding the concept of SM practices and there is a need to monitor the developments related to SM practices. Thus, there is a need to conduct a comprehensive review study for an improved understanding of the progress of SM practices. Accordingly, this study aims to identify various strategies followed by organizations for implementing SM practices. To identify various strategies, 89 articles were selected from the SCOPUS database (published between 2012 and 2022). These 89 articles were selected by using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework, a systematic literature review (SLR) technique. The selected articles were investigated based on year, journals, country, research methods, focused industry, and techniques followed. Bibliometric and network analysis were performed to establish cluster domains and to identify evolving research areas. Bibliometric analysis reveals that currently, the industrial communities is emphasizing circular economy models for SM practices. Network analysis identifies six domains of SM practices: lean manufacturing, renewable energy adoption, green manufacturing, life cycle assessment, zero waste manufacturing practices, and circular economy model. To conclude, the important contribution of this study is that it tracks the progress of SM practices over the years and highlights current SM practices.

The rise in abandoned oil wells across the globe poses a serious environmental and public health risk. These wells, which are frequently abandoned by defunct corporations or owing to regulatory gaps, pose substantial risks. They have the potential to leak methane, a potent greenhouse gas, and contaminate groundwater. Researchers estimate that there are between 2 and 3 million abandoned oil and gas wells in the United States. Out of these, over 117,000 wells, spread across 27 states, are classified as “orphaned”, and lack an identifiable party responsible for managing leakage or pollution risks. The escalating number of abandoned oil wells in the United States presents a dual challenge and opportunity in the realm of renewable energy. The global utilization of geothermal energy is on the rise, with approximately 72 countries harnessing this resource for various applications. About 24 of these countries generate electricity using geothermal energy through binary or flash cycle methods. The United States leads in geothermal electricity production, generating approximately 17,917 GWh annually. Global raise in geothermal energy utilization provides presents an opportunity to repurpose abandoned oil wells for geothermal energy production especially in the United States. These wells, often still possessing high temperatures and temperature gradients, can be converted into valuable geothermal resources, thus providing a sustainable energy solution and addressing the environmental hazards posed by the abandoned wells. This paper critically examines the feasibility of repurposing these wells for geothermal energy production, a strategy that offers a promising solution to both environmental hazards and the need for sustainable energy sources. Focusing on the technical, economic, and social dimensions, we present a comprehensive analysis that includes a case study of the Williston Basin in North Dakota, highlighting its potential for geothermal exploitation. Our approach employs Fourier's law of conduction to estimate the temperature at the bottom of selected wells. We address the critical challenges in this endeavor, ranging from ensuring the mechanical integrity of aging wells to navigating the economic and social implications of their repurposing. Our findings suggest that while significant challenges exist, especially in retrofitting old wells for new uses and garnering stakeholder consensus, the conversion of abandoned oil wells into geothermal energy sources is a viable and environmentally beneficial path forward. Finally representing a detailed exploration of their various potential geothermal and various applications This research contributes to the growing body of literature on sustainable energy solutions, offering practical insights and guidelines for future field implementations in the transition from fossil fuels to renewable energy sources.