Environmental Progress & Sustainable Energy最新文献

This work investigated the thermo-economics of gas-to-wire as a gas flaring mitigation option in a selected gas production facility, in the Niger Delta region of Nigeria, which flares 294 thousand standard cubic feet of natural gas, daily. The thermodynamics and economics aspects of the gas-to-wire plant were modeled, and implemented in the Engineering Equation Solver software. The thermodynamics was carried out to ascertain the technical feasibility of the proposed plant, while the economics analysis was done to ensure its cost competitiveness. The findings suggested that 19.2 MW of electricity could be generated from the flare gases. This could be achieved at a life cycle cost of 19.24 billion naira, and a unit cost of energy of 13.47 naira per kWh. Parametric simulation of interest rate, excess combustion air, exit temperature of flue gases, and expansion ratio of gas turbine were also done. Furthermore, the proposed power plant could meet the electricity needs of not less than 60,000 households in Delta State where the gas production facility is located at 550 kWh electricity per capita. The study has shown that gas-to-wire is one of the viable approaches to tackle gas flaring activities in Nigeria, to meet both the energy demand of its people and to preserve the environment. Thus, it is recommended that the Federal Government of Nigeria should give gas-to-wire a priority in its gas flaring utilization agenda.

The energy utilization rate of ships is low, and waste heat accounts for most of the energy loss of the main engine. In this work, a new method called the thermal power generation-organic Rankine cycle cascaded cycle is suggested to recover ships waste heat in a cascade utilization way. When comparing the performances of R245fa and R1234ze as working fluids, factors such as performance simulation, environmental protection, and safety were taken into account. Based on these simulation, the organic working fluid chosen is R245fa. On the basis of the cascaded cycle, the influence of working fluid flow rates on essential performance parameters, such as power-production cost, power output, thermal efficiency, and waste heat utilization of main engine flue gas is explored. The experimental system performs at its best for all metrics when the working fluid flow rates is 0.0403 kg/s, including power output of 483.25 W, thermal efficiency of 8.34%, power-production cost of 0.3464 $/kWh, and waste heat utilization of main engine flue gas of 69.05%.

Heavy metals contamination poses a significant environmental threat, which requires the development of eco-friendly bioremediation techniques. Present research work was conducted using wheat straw in submerged conditions for the growth of white rot fungus, Phlebia brevispora in the presence of varying concentrations of Cd, Pb, Ni, and Cr. The lignocellulolytic enzyme production ability of fungus was monitored. A wheat straw-based fixed-bed bioreactor was designed to treat metal-containing water in continuous mode. The fungus showed a positive influence on laccase production, cellulase production, and lignin peroxidase activity. As observed through atomic absorption spectroscopy (AAS), Cr removal efficiency was 78%–80%, regardless of the initial metal concentration. The Cr was also found on the surface of fungal mycelium as per the results obtained from SEM–EDX. The continuous bioreactor achieved 98%–99% metal removal, making it a natural and cost-effective solution for metal removal from wastewater using P. brevispora.

Energy conservation and sustainability to reduce the dependence on conventional sources have resulted in modified or advanced process practices. One such is the use of nanofluids for enhanced energy efficiency. However, such practices must not be at the cost of environmental hazards. The current study emphasizes bio-based nanofluids formulated at five different volumetric concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) using Flamboyant (Royal Poinciana) tree bark nanoparticles with ethylene glycol as base fluid. The nanoparticles synthesized by cost-effective extensive ball milling technique were spherical in shape. Analyzing the nanofluid with TEM confirms the particles as evenly distributed with an average diameter of 26 nm. Elemental analysis shows that the bio powder contains oxides of Calcium and Silicon. The pH, electrical conductivity, and viscosity of the prepared flamboyant tree bark-ethylene glycol (FTB-EG) nanofluid were quantified between 20 and 70°C. Although the properties enhanced with increase in concentration, the viscosity and pH decreased with temperature rise, while the electrical conductivity behaved contradictory. The maximum and minimum values of the properties were attributed to 1.0% and 0.2% concentrations, respectively. The correlations were proposed and the deviation between the measured and correlation data was less than 10%.

Solar desalination is a broad research field in the production of freshwater. The efficiency of the natural conversion solar desalination system is the only limitation to becoming its commercialization. It needs 1 m² area for getting approximately 4.5 L of fresh water/day. In active methods 1 m² area of solar still produce yield up to 10 L/day. In this study a new technology of fixing the photovoltaic cell (PV cells) in the natural passive solar still condenser glass to harvest both freshwater as well as electrical power generation is proposed. The experiments were carried out with conventional solar still of a glass surface area of 0.5 m², still with an effective glass surface area of 0.3812 m² and 36 PV cells taken up area of 0.1188 m², and still with effective glass surface area of 0.3020 m² and 60 PV cells taken up area of 0.198 m². The study found that conventional solar still produced 2140 mL/day of yield, still with 36 PV cells produced 1380 mL/day of yield and 98 W of electrical power and still with 60 PV cells produced 840 mL/day of yield and 165 W of electrical power. This hybrid system, solar still with PV cells, produce both fresh water and electrical power. The fresh water yield and electrical power generation depends on the effective area of the solar still glass surface area and area occupied by PV cells attached to the solar still glass cover.

Pretreated lignocellulosic residues are suitable substrates for cellulases production by filamentous fungi. In the current work, plantain rachis was pretreated with sequential acid and alkali and then used as the main carbon source for cellulases production. First, a full 2³ factorial design and response surface methodology (RSM), based on central composite rotatable design (CCRD), were carried out to cellulases production media optimization from plantain rachis by Penicillium oxalicum. The cellulases production was evaluated in flasks and bioreactor scale; in parallel, the addition of possible cellulases inductors was evaluated in flasks: molasses, beer bran, oat bran, and wheat bran. Results from statistical analyses with a level of confidence of 95% demonstrated that the concentration of ammonium sulfate must be kept at 1.625 g/L. The optimum urea and yeast extract concentrations were 0.560 g/L and 0.250 g/L, respectively. Cellulases volumetric productivities were higher in instrumented bioreactor than in flasks: 78.03% for exoglucanase, 10.87% for endoglucanase, 1.58% for β-glucosidase, and 44.36% for FPU. Therefore, P. oxalicum was able to produce cellulases from plantain rachis in flasks and bioreactor, and molasses was the additional inductor that presented an increment in cellulases activities: endoglucanase 15%, exoglucanase 81%, and β-glucosidase 55%.

This review explores the innovative utilization of industrial effluents in biorefinery applications, addressing the environmental challenges posed by the complex mixture of pollutants in industrial wastewater. It emphasizes the transformation of these effluents into valuable resources, such as biofuels, biochemicals, and bioplastics, through advanced biotechnological processes including anaerobic digestion, fermentation, enzymatic conversion, and microbial biomass production. The study highlights the critical role of microbial biocatalysts in breaking down diverse pollutants and transforming waste into wealth, thereby contributing to sustainable industrial practices and a circular economy. Challenges such as variability in effluent composition, inhibitory substances, and the necessity for robust bioprocesses are discussed, along with suggestions for future research directions like effluent characterization, development of specialized microbial consortia, and effective monitoring and control strategies. The review underscores the importance of collaboration between industry, academia, and government to advance biorefinery technologies, ultimately advocating for a sustainable and resource-efficient future through the innovative treatment of industrial wastewaters.

The Middle East and North Africa (MENA) region faces significant challenges in the production of sustainable aviation fuel (SAF) due to high costs, limited feedstock availability, and underdeveloped infrastructure. However, the region has diverse feedstock options and can leverage existing refining capabilities and advanced conversion technologies for SAF production. Addressing these challenges requires research and development (R&D) collaboration, supportive policies, and international knowledge exchange. To promote the production of SAF in the MENA region, a comprehensive strategy is required that includes collaboration, policy alignment, research and development, infrastructure development, and training. Market incentives such as regulations and financial support can help drive demand for SAF. Collaborating with international organizations can improve knowledge sharing and promote sustainable practices. Research and development collaboration is crucial for innovation and establishing a strong SAF industry. Policy harmonization can create a supportive framework for investment and innovation. Monitoring and reporting mechanisms can ensure transparency and verify sustainability. By addressing these aspects, the region can become a leading hub for SAF production and contribute to a sustainable aviation industry.

This study presents quantitative results of charging experiments conducted on cascaded thermal energy storage system (CTESS) integrated with external compound parabolic concentrator solar collector (XCPCSC). Increasing mass flow rate in 2-stage CTESS integrated with XCPCSC resulted in a 30% reduction in initiation time of phase change materials (PCMs) during charging, with a higher mass flow rate of 0.025 kg/s. However, due to disparate melting point temperatures of PCMs, phase transition in the two-stage CTESS did not occur simultaneously, leading to poor heat transfer rates within the CTESS. To address this, study extended number of phases from two to three, resulting in a 1.5-fold increase in rate of heat transfer compared to 2-stage PCM system. The simultaneous melting processes at various stages in the CTESS maximized energy absorption, leading to a 25% increase in system efficiency. Notably, the values of energy stored efficiency and over-all efficiency reached their peak values of 95% and 60%, respectively, between t = 12.00 h and t = 13.00 h. This time period also saw a significant increase in collector efficiency to 72%. These quantitative findings highlight importance of mass flow rate and PCM arrangement in achieving efficient heat transfer and system performance in a CTESS integrated with XCPCSC.