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Showing records 101 to 125 of 3342. [First] Page: 1 2 3 4 5 6 7 8 9 Last
A Volume Fracturing Percolation Model for Tight Reservoir Vertical Wells
Dianfa Du, Peng Liu, Lichuan Ren, Yuan Li, Yujie Tang, Fanghui Hao
November 30, 2023 (v1)
Subject: Environment
Keywords: Laplace transform, nonlinear seepage, productivity, volume fracturing vertical well
Based on the non-linear seepage characteristics of tight reservoirs and the reconstruction mode of vertical wells with actual volume fracturing, a seven-area percolation model for volume fracturing vertical wells in tight reservoirs is established. Laplace transform and Pedrosa transform are applied to obtain analytical solutions of bottom hole pressure and vertical well production under a constant production regime. After verifying the correctness of the model, the influence of the fracture network parameters on the pressure and production is studied. The research results indicate that as the permeability modulus increases, the production of volume fracturing vertical wells decreases. The penetration ratio of the main crack and the half-length of the main crack have a small impact on production, while the diversion capacity of the main crack has a significant impact on the initial production, but it is ultimately limited by the effective volume of the transformation. Under constant pr... [more]
A Modelling-Based Framework for Carbon Emissions Calculation in Additive Manufacturing: A Stereolithography Case Study
Vasiliki C. Panagiotopoulou, Aikaterini Paraskevopoulou, Panagiotis Stavropoulos
November 30, 2023 (v1)
Subject: Environment
Keywords: additive manufacturing, carbon calculation framework, carbon emissions, carbon footprint, holistic framework, stereolithography
Manufacturing is one of the most heavily contributing sectors to global warming via its high carbon emissions. Initiatives such as the Green Deal and Sustainable Goals by the United Nations are supporting the reduction of carbon emissions in the manufacturing sector, which can be completed by making manufacturing processes more sustainable and with less carbon footprint. This also applies to novel manufacturing processes such as additive manufacturing (AM). In this work, a previously developed framework for carbon footprint calculation was tailor-made and applied to a specific stereolithography (SLA) case. The different steps of the SLA were categorised per process, machine tool and system level, and the respective carbon emissions were calculated, either theoretically or via a life cycle assessment software. The carbon emissions at the process level were significant when compared to the total carbon emissions, and the carbon emissions of the isopropanol (IPA) bath accounted for more t... [more]
Review on Waste-to-Energy Approaches toward a Circular Economy in Developed and Developing Countries
Shahabaldin Rezania, Bahareh Oryani, Vahid Reza Nasrollahi, Negisa Darajeh, Majid Lotfi Ghahroud, Kamyar Mehranzamir
November 30, 2023 (v1)
Subject: Environment
Keywords: circular economy, developed and developing countries, policies and regulations, solid waste management, waste-to-energy
International interest in using waste-to-energy (WtE) technology toward a circular economy (CE) is developing, spurred by environmental challenges such as inefficient solid waste dumping, pollution, and resource depletion. Incineration, pyrolysis, gasification, landfill, and anaerobic digestion are standard WtE technologies. Although these methods have been used for many decades, all countries try to implement the best plans based on their technologies and capacities. Therefore, an up-to-date comprehensive study is needed to evaluate the existing barriers to draw a logical roadmap for WtE to CE. Therefore, this review addresses the recent policies adopted by developed and developing countries for WtE technologies. Based on the findings, most countries seek the most cost-effective and environmentally sustainable pathways in WtE to CE; meanwhile, international collaboration and governmental support are needed to overcome the existing barriers and find a sustainable and economically viabl... [more]
Bioavailability, Sources, and Transfer Behavior of Heavy Metals in Soil−Crop Systems from a High Geological Background Area Impacted by Artisanal Zn Smelting in Guizhou Province, Southwest China
Honghong Ma, Chen Zhao, Li Zhang, Zhizhuo Liu, Fugui Zhang, Huiyan Wang, Fei Guo, Shiqi Tang, Zheng Yang, Min Peng
November 30, 2023 (v1)
Subject: Environment
Keywords: bioavailability, farmland soil, heavy metals, soil contamination, soil–plant transfer factor
The environmental risk posed by heavy metals in agricultural soil is primarily influenced by their sources, bioavailability, and geochemical transfer behavior. This study focused on Weining County, a region in Guizhou province, Southwest China, with a high geological background and long-term impact from artisanal Zn smelting. Vertical soil profiles, crop, and rhizospheric soil samples were collected and analyzed for heavy metal concentration (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, and Zn) including the total concentration and chemical fraction. The results revealed elevated concentrations of Cd (range: 0.7−6.9 mg·kg−1), Co (range: 19.3−120.0 mg·kg−1), Cu (range: 71.6−386.0 mg·kg−1), Ni (range: 51.0−121.0 mg·kg−1), and V (range: 310.0−721.0 mg·kg−1) in all soil samples compared to the background values of Guizhou Province. Chemical fractionation analysis indicated that Cr, Ni, As, Cu, and Zn were predominantly present in the residual fraction, while Hg and Pb were predominantly found in the... [more]
Exploring the Feasibility of Carbon Capture Onboard Ships
Sadi Tavakoli, Gunnar Malm Gamlem, Donghoi Kim, Simon Roussanaly, Rahul Anantharaman, Kevin Kusup Yum, Anders Valland
November 6, 2023 (v1)
Subject: Environment
Keywords: amine, Carbon Capture, Carbon Dioxide, IMO, Maritime
International shipping is crucial for global freight transport, but is mainly based on fossil fuels, leading to significant greenhouse gas (GHG) emissions. Global GHG emissions must peak by 2025 and drop by at least 43% by 2030 to limit global warming within 1.5◦C. This calls for urgent action in all sectors as well as shipping. Scaling up alternative fuels may take too long, considering technical modifications onboard the vessels, as well as fuel production and infrastructure for distribution. Many alternative fuels are also inherently dependent on access to clean electricity, which is already in a shortage. Carbon capture from ships is another route to emission reduction that can be implemented faster and without increasing the demand for renewable electricity.
Tankers, dry bulk carriers, and container vessels contribute a majority of global shipping emissions and are therefore prime candidates for carbon capture and storage. Solvent-based post-combustion capture is mature and suita... [more]
Changing Law of Permeability of Coal Reservoirs under Variable Pressure Conditions and Its Influence on Extraction Efficiency of Coalbed Methane
Jianbao Liu, Zhimin Song, Chengtao Yang, Bing Li, Jiangang Ren, Shengjie Chen
September 21, 2023 (v1)
Subject: Environment
Keywords: bedding direction, extraction efficiency, gas pressure, metamorphic degree, permeability, true triaxial seepage experiment
Coal permeability data are critical in the prevention and control of coal and gas outbursts in mines and are an important reservoir parameter for the development of coalbed methane. The mechanism by which permeability is affected by gas pressure is complex. We used a self-developed true triaxial seepage experimental device that collects lignite and anthracite coal samples, sets fixed axial pressure and confining pressure, and changes gas pressure by changing the orientation of the coal seam to study the influence of the gas pressure on the permeability of the coal seam under the conditions of different coal types and different bedding orientations. Coal permeability decreased rapidly and then decreased slowly and tended to be stable with the increase in gas pressure. This conformed to the power exponential fitting relationship, and the fitting degree reached more than 99%. The comparison of the two anthracite coal samples showed that the sample’s permeability with a bedding plane verti... [more]
The Fermentation of a Marine Probiotic Bacterium on Low-Cost Media Formulated with Industrial Fish Gelatin Waterstreams and Collagen Hydrolysates
José Antonio Vázquez, Adrián Pedreira, Iván Salmerón, Dyah H. Wardhani, Jesus Valcarcel
September 21, 2023 (v1)
Subject: Environment
Keywords: bioconversion, collagen hydrolysates, gelatin effluents, marine probiotic bacteria, Phaeobacter sp. DIFR 27-4, Renewable and Sustainable Energy
Chemical effluents generated by the isolation of fish gelatin and collagen hydrolysates produced from the enzyme proteolysis of skin wastes are protein-rich substrates that could be used as nutrients in bacterial bioprocessing. In this study, the suitability of such nutrients in supporting the growth of a marine probiotic bacterium, Phaeobacter sp. DIFR 27-4, was studied. Both gelatin effluents and collagen hydrolysates were obtained from the skins of shark, tuna, salmon and turbot. The chemical composition of the substrates included the complete presence of all quantified amino acids. Low-cost marine culture media were formulated with these protein materials alongside a very low concentration of yeast extract and marine water. In batch cultures with gelatin effluents, the growth rates of the strain DIFR 27-4 were somewhat lower than those found in the control marine commercial media. In the case of the hydrolysates, the bacterial production of biomass was similar or higher than that o... [more]
Application of Landfill Gas-Water Joint Regulation Technology in Tianjin Landfill
Jun Liu, Tianqi Pan, Huihui Zhao, Yan Guo, Guanyi Chen, Li’an Hou
September 21, 2023 (v1)
Subject: Environment
Keywords: aerobic remediation, biochemical treatment, dynamic respiratory index, rapid stabilization
Landfills have long been widely used to dispose of Municipal Solid Waste (MSW). However, many landfills have faced early closure issues in recent years due to overload operations. Although in-situ aeration technology can quickly stabilize MSW, low oxygen utilization rates present a general problem that results in high energy-consuming and operating costs. This research aims to improve oxygen utilization efficiency by observing the dynamic respiratory index and the removal of contaminants. Three continuous reactors were constructed and designed with targeted aeration and re-circulation schemes for different landfill ages. The results show that a well-designed aerobic, semi-aerobic, and anaerobic reactor can fully degrade the organic components of MSW with different landfill ages, and the quantity of waste has been reduced by more than 60%. Additionally, it was disclosed that gas-water joint technology has a promotional effect on activating microorganisms.
Evaluating Nationwide Non-Point Source Pollution of Crop Farming and Related Environmental Risk in China
Yang Duan, Hongqiang Jiang, Xiao Huang, Wenhui Zhu, Jie Zhang, Bo Wang, Wenjun Wu
September 21, 2023 (v1)
Subject: Environment
Keywords: non-point source pollution, nutrient balance, nutrient budget, pollution risk assessment, spatial and temporal distribution
The increase in non-point source (NPS) pollution from agricultural cultivation and production sources has been cited as one of the main reasons for water eutrophication. This study built a national NPS database and estimated the nutrient (including both nitrogen (N) and phosphorus (P)) balance and NPS pollution of crop farming at the county level in 2015. Finally, the NPS pollution risks were assessed, and relative policy suggestions were provided. The results indicated that (1) in 2015, the total amounts of N and P surpluses in China were 7.95 and 7.39 million tons, respectively. The south of the Yangtze River had a relatively higher nutrient surplus compared to that in northern China. (2) The NPS emissions for N and P in China were 168.84 × 104 tons and 8.93 × 104 tons, respectively, with the highest NPS loads occurring in the eastern part of the Sichuan Basin, southern China and southwestern China, while the lowest loads occurred in northeast China. (3) The potential risk assessment... [more]
Doxycycline Removal by Solar Photo-Fenton on a Pilot-Scale Composite Parabolic Collector (CPC) Reactor
Faiza Bensaibi, Malika Chabani, Souad Bouafia, Hayet Djelal
September 21, 2023 (v1)
Subject: Environment
Keywords: CPC reactor, doxycycline, germination index, solar photo-Fenton process, wastewater treatment
In this study, the solar photo-Fenton (SPF) process was investigated for the degradation of doxycycline (DOX) using a solar compound parabolic collector (CPC) reactor and a borosilicate serpentine tube with an irradiated volume of 1.8 L. The influence of the operating parameters, such as H2O2, Fe2+ dosage, and DOX concentration, was investigated. The optimum H2O2, Fe2+ dosage, and DOX concentration were found to be 4, 0.1, and 0.06 mM, respectively. The results of photo-Fenton experiments fitted the pseudo-first-order kinetic equation (R2 = 0.99). The efficiency of the treatment under optimized conditions was analyzed by an HPLC analysis of the samples, chemical oxygen demand (COD), and total organic carbon (TOC). The results obtained showed that the solar photo-Fenton process achieved a DOX degradation of 95.07%, a COD elimination of 81.43%, and a TOC elimination of 73.05%. The phytotoxicity tests revealed a 73.32% decrease in the germination index of watercress seeds, demonstrating t... [more]
Calibration of Sensor Network for Outdoor Measurement of PM2.5 on High Wood-Heating Smoke in Temuco City
Carlos Muñoz, Juan Huircan, Francisco Jaramillo, Álex Boso
September 20, 2023 (v1)
Subject: Environment
Keywords: air pollution, low-cost sensor, particle-matter calibration, spatial–temporal distribution
In order to ascertain the spatial and temporal changes in the air quality in Temuco City, Chile, we created and installed a network of inexpensive sensors to detect PM2.5 particulate matter. The 21 measurement points deployed were based on a low-cost Sensiron SPS30 sensor, complemented with temperature and humidity sensors, an Esp32 microcontroller card with LoRa and WiFi wireless communication interface, and a solar charging unit. The units were calibrated using an airtight combustion chamber with a Grimm 11-E as a reference unit. The calibration procedure fits the parameters of a calibration model to map the raw low-cost particle-material measurements into reliable calibrated values. The measurements showed that the concentrations of fine particulate material recorded in Temuco present a high temporal and spatial variability. In critical contamination episodes, pollution reaches values as high as 354 µg/m3, and at the same time, it reaches 50 µg/m3 in other parts of the city. The con... [more]
Analysis of Greenhouse Gas Emissions Characteristics and Emissions Reduction Measures of Animal Husbandry in Inner Mongolia
Yingnan Cao, Xiaoxia Yang, Fang Yang, Ying Sun, Qianqian Wang, Futian Ren, Lei Nie, Aodemu, Weiying Feng
September 20, 2023 (v1)
Subject: Environment
Keywords: animal husbandry, emissions reduction, greenhouse gases
Global warming has had a profound impact on human life, with animal husbandry being a significant contributor to greenhouse gas emissions and playing a crucial role in the global greenhouse gas budget. Inner Mongolia is a major contributor to these emissions, making it vital to study the link between greenhouse gas emissions and animal husbandry in this region for the purpose of reducing emissions. In this study, the emissions of greenhouse gases (CH4, N2O, and CO2) from livestock and poultry breeding from 2010 to 2020 and the emissions of each city from 2020 were estimated, the emissions characteristics were analysed, and the low carbon emissions reduction technical measures were proposed. The results show that (1) the overall greenhouse gas emissions from 2010 to 2020 in Inner Mongolia showed a fluctuating trend; the main emissions sources were gastrointestinal fermentation and faecal management. The annual average CH4 emissions were 994,400 ta−1, and the annual average N2O emissions... [more]
The Influence of a Key Indicator kv on the Diffusion Range of Underwater Oil Spill
Hong Ji, Yaxin Wang, Ting Wang, Ke Yang, Zhixiang Xing
September 20, 2023 (v1)
Subject: Environment
Keywords: a key indicator kv, fitting curve, oil spill, physical model experiment, submarine pipeline
As oil spills cause harm to the survival and environment of the ocean, the objective of the present paper is to study the oil migration range using the key indicator kv, which is defined as the ratio of oil spill speed to ocean current speed. The correctness of diffusion models created and estimated for subsea oil spills can be verified by experiments. We also considered the effect of key indicators on the horizontal and vertical dispersion ranges of oil spills. The study’s findings show that, under various kv settings, the horizontal and vertical spreading heights of oil spills both increase as kv rises. When kv is equal, the leakage velocity and water flow velocity increase synchronously, and over time, the horizontal distance and vertical diffusion height of the oil spill gradually increase. In the early stages of an oil spill, when kv = 50, 100, or 150, the vertical spreading velocity will rapidly decrease. The vertical spreading speed of spilled oil increases as kv rises when the... [more]
Environmental Life Cycle Analysis of Açaí (Euterpe oleracea) Powders Obtained via Two Drying Methods
Natalia Salgado-Aristizabal, Tatiana Agudelo-Patiño, Sebastian Ospina-Corral, Ignacio Álvarez-Lanzarote, Carlos Eduardo Orrego
September 20, 2023 (v1)
Subject: Environment
Keywords: açaí crop, environmental life cycle analysis, Euterpe oleracea, spray drying, vacuum drying, waste management
Açaí is a fruit native to Brazil that is found in Colombia, and it is recognized for containing more than 90 compounds with anticancer, anti-inflammatory, and other biological activities. In this study, a cradle-to-gate life cycle analysis (LCA) was conducted for the production of açaí powder, following the methodology outlined in the ISO 14040 standard. The investigation focused on examining the impact of utilizing or not utilizing the residues generated during the pulp extraction step as fertilizers. Four scenarios were analyzed and compared: (i) production of açaí powder via vacuum drying, (ii) via spray drying, and via the same two types of drying but using residues from the pulping operation as fertilizer (Scenarios 3 and 4). It was found that to produce 1 kg of açaí in a crop cycle, 1.17 kg of CO2 eq is produced. The drying stage in Scenarios 1 and 2 generated 8.04 and 7.93 kg of CO2 eq, respectively. Similarly, when solid waste is used as fertilizer, CO2 emissions barely increas... [more]
A Comprehensive Model for Evaluating Titanium Industry Security in China
Xiangwei Hui, Ming Qi, Wenhao Wang, Sen Yang, Chengqi Zhang
September 20, 2023 (v1)
Subject: Environment
Keywords: entropy weight-TOPSIS, grey correlation analysis, Renewable and Sustainable Energy, security system, titanium industry chain
Currently, China is the largest consumer of titanium (Ti), yet the development of its Ti industry is limited by numerous factors, such as industrial structure imbalance. This study aimed to evaluate the security of China’s Ti industry from 2010 to 2020, seeking to identify relevant issues and propose policy strategies. Firstly, a comprehensive evaluation system for Ti industry security was established, encompassing aspects of availability, economics, and sustainability. Secondly, the entropy weight technique for order preference by similarity to an ideal solution (TOPSIS) combination method and gray correlation method were employed to assess the safety level of China’s Ti industry chain in each year from 2010 to 2020. Additionally, the coupling degree and sensitivity were used to analyze the dimension layers and index system to determine those that negatively impact the safety level of the Ti industry chain. The analysis results reveal that the economic level exerts a significant influ... [more]
Tailing Ash for the Removal of Methylene Blue from Aqueous Solutions by Batch Adsorption
Cik Jamla Farhan bt Yahya, Thomas Shean Yaw Choong, Fan Li, Wan Azlina Wan Ab Karim Ghani, Farah Nora Aznieta Abd Aziz, Siti Nurul Ain Md. Jamil
September 20, 2023 (v1)
Subject: Environment
Keywords: Adsorption, dye, tailing ash
One of the more problematic textile wastewaters to manage is dyeing wastewater, especially methylene-blue-containing wastewater. Its release has a significant negative impact on ecosystems, which could harm the environment. Adsorption techniques are still an efficient technology to eliminate and remove the coloring agent. Tailing ash, obtained from the floatation process, was selected as an adsorbent in the present study. The purpose of this study was to analyze the performance of tailing ash (TA) for MB removal. The effects of operating parameters investigated were pH (2−10), stirring speed (50−150 rpm), initial dye concentration (20−100 mg/L), contact time (120 min), adsorbent dosage (0.5−2.5 g), and temperature (25−45 °C). The performance of TA pretreated with hydrogen peroxide (H2O2) and thermal tailing ash were also investigated. The experimental results for batch adsorption indicated that 96.23% removal of methylene blue took place at the optimum condition (pH = 10, initial adsor... [more]
A Study on Environmental Trends and Sustainability in the Ocean Economy Using Topic Modeling: South Korean News Articles
Hee Jay Kang, Changhee Kim, Sungki Kim, Chanho Kim
September 20, 2023 (v1)
Subject: Environment
Keywords: environmental trends, ocean economy, Renewable and Sustainable Energy, text mining, topic modeling
The ocean economy plays a critical role in global economic growth, yet it confronts substantial environmental risks. This study employs topic modeling of South Korean news articles to analyze the evolving trends of environmental risks and sustainability in ocean economy. A dataset comprising 50,213 articles from 2008 to 2022 is examined, revealing prevalent environmental concerns that have persisted over the years. The findings demonstrate an increasing emphasis on sustainability and marine environmental issues, as evidenced by prominent keywords related to construction, safety, plastic pollution, and ecosystem conservation. Through Latent Dirichlet Allocation (LDA) in topic modeling, 10 distinct themes are identified, encompassing sustainable fisheries management, accident and disaster response, polar environment, carbon neutrality, microplastic pollution, habitat ecosystems, cruise tourism development, nuclear power plant pollution, and infectious diseases. The outcomes highlight the... [more]
Dyes and Heavy Metals Removal from Aqueous Solutions Using Raw and Modified Diatomite
Simona Gabriela Muntean, Maria Andreea Nistor, Raisa Nastas, Oleg Petuhov
September 20, 2023 (v1)
Subject: Environment
Keywords: Adsorption, equilibrium, kinetic, pollutant, Wastewater
The progress of the textile industry has led to a severe increase in the discharge of colored effluents, polluted with dyes and metal ions (non-biodegradable, carcinogenic to humans and environmental hazards). The implementation of effective methodologies and materials for the treatment of wastewater has become an urgent requirement. The present work describes the application of two samples of mineral materials—Ghidirim diatomite and modified diatomite—as adsorbents for the removal of dyes—Acid Blue 350, Methylene Blue, Basic Red 2—and of metal ions—copper, zinc, and lead—from aqueous solutions. In order to determine the optimal working conditions by which to ensure maximum removal efficiency, the influence of the nature and amount of the sorbent, the initial concentration of pollutant, and the temperature were studied. Working under normal conditions (room temperature, solution pH) efficiencies greater than 80% were obtained for the removal of dyes and metal ions. The adsorption fitte... [more]
Evaluation of the Impact of Buffer Management Strategies on Biopharmaceutical Manufacturing Process Mass Intensity
Kevin Gibson, Jorge C. Oliveira, Denis Ring
September 20, 2023 (v1)
Subject: Environment
Keywords: biopharmaceutical manufacturing, buffer management, environmental impact, process mass intensity
There is an increasing demand to improve the overall sustainability of the biopharmaceutical industry. A barrier to improvement has been the limited research undertaken in the area of environmental impact of key design decisions. The aim of this study was to perform a comprehensive evaluation of the impact of buffer management strategy and technology selection on overall process efficiency using process mass intensity (PMI) as a metric for comparison. The environmental impact of buffer management has yet to be fully understood, despite buffers being one of the most resource-intensive aspects of biopharmaceutical manufacturing. A detailed process model was used to evaluate the impact of buffer management on a monoclonal antibody (MAB) process at the 2000 L scale. This was achieved by means of a non-replicated full factorial design composed of six variables: product titre, quantity of unique buffers, preparation frequency, single-use threshold and equipment cleaning duration with two lev... [more]
Impact of Microplastics on the Fate and Behaviour of Arsenic in the Environment and Their Significance for Drinking Water Supply
Malcolm Watson, Aleksandra Tubić, Marko Šolić, Jasmina Nikić, Marijana Kragulj Isakovski, Jasmina Agbaba
September 20, 2023 (v1)
Subject: Environment
Keywords: arsenic, drinking water, heavy metals, microplastics, nanoplastics
The ubiquitous presence of microplastics (MPs) is a topic of great concern. Not only do MPs themselves represent potential toxicants for human health, they are never found alone in the environment and interact with and adsorb a variety of toxicologically significant pollutants. This review summarises recent work on interactions between MPs and heavy metals in the environment, with a special focus on arsenic, one of the most widespread and problematic water contaminants. Evidence for the adsorption of arsenic onto MP surfaces is given and the recent research into the consequences of this phenomenon for freshwater, marine, and soil environments presented. Finally, the lack of research into the significance of interactions between arsenic and MPs during drinking water treatment is highlighted. The performance of arsenic removal technologies is governed by a multitude of different factors, and with MPs detected in water sources all over the world, data on how these MPs impact the removal o... [more]
Extraction of Vanadium from the Spent Residuum Hydroprocessing Catalysts by Fenton-like Reaction Followed with Alkaline Leaching
Yuefen Lv, Ge Zhao, Cailong Shen, Yanzhen Chen, Yiqun Fan, Guangji Zhang, Chao Yang
August 3, 2023 (v1)
Subject: Environment
Keywords: alkali leaching, Fenton-like reaction, oil removal, spent residuum hydroprocessing catalyst, vanadium
Spent residuum hydroprocessing (RHDP) catalysts are hazardous waste bearing high-content vanadium and large amounts of oily pollutants. In this paper, a process featuring a Fenton-like reaction and alkaline leaching was proposed to recover vanadium from spent RHDP catalysts. In the first step, a Fenton-like reaction using peroxide was conducted to degrade the oily pollutants and make the surface of the spent catalyst becomes hydrophilic. In the second step, the vanadium-containing deposit on the catalyst was leached with 0.5 M Na2S2O8 at 70 °C for transforming vanadium sulfide to oxide in 5 h. In the last step, alkaline leaching was employed to dissolve vanadium from the oxidizing residue at 80 °C for 1 h. It was found that the accumulated leaching efficiency of vanadium can reach up to 90.92%, and only a small part of aluminum and sulfur was dissolved. These results indicated that this combined process can extract vanadium selectively from spent residuum hydroprocessing catalysts unde... [more]
Investigation of the Interface Effects and Frosting Mechanism of Nanoporous Alumina Sheets
Song He, Heyun Liu, Yuan Zhang, Haili Liu, Wang Chen
August 3, 2023 (v1)
Subject: Environment
Keywords: frosting, interface effect, mechanism, nanoporous alumina sheet
Nanoporous alumina sheets can inhibit the growth of the frost layer in a low-temperature environment, which has been widely used in air-conditioning heat exchangers. In this study, nanoporous alumina sheets with pore diameters of 30 nm, 100 nm, 200 nm, 300 nm, and 400 nm were prepared by using the anodic oxidation method with the conventional polished aluminum sheet as the reference. A comprehensive and in-depth analysis of the frosting mechanism has been proposed based on the contact angle, specific surface area, and fractal dimension. It was found that compared with the polished aluminum sheet, the nanoporous alumina sheets had good anti-frost properties. Due to its special interface effects, the porous alumina sheet with a 100 nm pore diameter had strong anti-frost performance under low temperatures and high humidity. In an environment with low surface temperature and high relative humidity, it is recommended to use hydrophilic aluminum fins with large specific areas and small fract... [more]
A Transient Productivity Prediction Model for Horizontal Wells Coupled with Oil and Gas Two-Phase Seepage and Wellbore Flow
Wenqi Ke, Wei Luo, Shiyu Miao, Wen Chen, Yaodong Hou
August 3, 2023 (v1)
Subject: Environment
Keywords: capacity prediction, horizontal wells, saturation pressure, transient model, two-phase seepage
Capacity prediction is the basis for the optimization of oil and gas well production work systems and parameter optimization design. Horizontal wells are becoming increasingly popular for oil and gas extraction. However, the seepage law of reservoirs produced with horizontal wells is more complicated than that of reservoirs produced with vertical wells, especially when the bottom hole flowing pressure or formation pressure is less than the saturation pressure of crude oil in the reservoir. Oil and gas two-phase seepage can occur in a part or all areas of the wellbore and reservoir. Because the oil and gas two-phase seepage characteristics of reservoir oil well production will be reduced—possibly greatly reduced—the formation seepage law is complex. Thus, it is very important to better predict the horizontal well capacity. To address this, a method and process of establishing a transient calculation model of two-phase flow in horizontal wells are introduced in detail from three aspects:... [more]
Diving into Fish Valorisation: Review Opportunities and Analyzing Azorean Fish Data
Nádia Valério, Margarida Soares, Cândida Vilarinho, Manuela Correia, Joana Carvalho
August 3, 2023 (v1)
Subject: Environment
Keywords: blue economy, circular economy, fish by-product valorisation, fish waste, sustainable marine sources, the Azores
In response to the exponential growth in world population, there has been a striking surge in the volume of discarded fish worldwide. This surge is particularly evident in the fish processing industry, where a substantial amount of waste is generated, posing significant environmental concerns. Consequently, the repurposing and utilisation of these waste materials have emerged as pivotal processes for the preservation of marine resources. By employing innovative strategies, valuable products can be extracted from these fish by-products, offering not only economic advantages but also contributing to mitigating environmental impacts. This comprehensive literature review focuses on exploring diverse avenues for using fish waste and extracting high-value materials such as bioactive peptides, collagen, and enzymes, elucidating their potential applications across various industries. The literature review also demonstrates the possibility of extracting various bio-compounds from highly diverse... [more]
A Novel Pattern Recognition based Kick Detection Method for Offshore Drilling Gas Kick and Overflow Diagnosis
Yang Xu, Jin Yang, Zhiqiang Hu, Dongsheng Xu, Lei Li, Chao Fu
August 3, 2023 (v1)
Subject: Environment
Keywords: gas invasion, kick, offshore drilling, overflow, pattern recognition, threshold method
In offshore drilling, accidents such as gas invasion, overflow, and kicks are unavoidable, and they can escalate into blowouts and other catastrophic events, resulting in casualties and significant economic losses. Therefore, ensuring drilling safety requires precise monitoring of gas invasion and overflow. Currently, most overflow monitoring methods used at drilling sites are based on threshold criteria. However, the monitoring parameters obtained during actual drilling operations often contain noise signals, which makes it challenging for threshold-based methods to achieve a balance between improving accuracy and minimizing false positives. This paper proposes a novel method called Pattern-Recognition-based Kick Detection (PRKD) for diagnosing overflow in offshore drilling. The PRKD method utilizes the overflow evolution process by integrating multiphase flow calculations, data filtering theory, pattern recognition theory, the Bayesian framework, and other theoretical models. By anal... [more]
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