23,177 research outputs found


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    The reduction of greenhouse gases is an assumed objective of the European Community. Thus, in the future, natural gas transport and distribution pipelines will also have to deal with ensuring the transport of mixtures formed between hydrogen, biomethane and natural gas from fossil resources. Considering the increase in the amount of biomethane and the increase in the amount of green hydrogen produced, these fuels’s use in natural gas distribution networks is expected. The article presents an analysis of hydrogen production methods as well as numerical models of hydrogen transportation and mixing with natural gas. Also, there are presented the results obtained at the international level regarding the thresholds for the use of hydrogen in the fossil fuel of natural gas type, as well as the effects produced by the presence of this gas on the transport and supply systems. Numerical models of mixing and dynamic behavior of the new fuel obtained are also analyzed

    Pathways for the Valorization of Animal and Human Waste to Biofuels, Sustainable Materials, and Value-Added Chemicals

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    Human and animal waste, including waste products originating from human or animal digestive systems, such as urine, feces, and animal manure, have constituted a nuisance to the environment. Inappropriate disposal and poor sanitation of human and animal waste often cause negative impacts on human health through contamination of the terrestrial environment, soil, and water bodies. Therefore, it is necessary to convert these wastes into useful resources to mitigate their adverse environmental effect. The present study provides an overview and research progress of different thermochemical and biological conversion pathways for the transformation of human- and animal-derived waste into valuable resources. The physicochemical properties of human and animal waste are meticulously discussed, as well as nutrient recovery strategies. In addition, a bibliometric analysis is provided to identify the trends in research and knowledge gaps. The results reveal that the USA, China, and England are the dominant countries in the research areas related to resource recovery from human or animal waste. In addition, researchers from the University of Illinois, the University of California Davis, the Chinese Academy of Sciences, and Zhejiang University are front runners in research related to these areas. Future research could be extended to the development of technologies for on-site recovery of resources, exploring integrated resource recovery pathways, and exploring different safe waste processing methods

    Analysis of Sectoral Energy Demand in Pakistan

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    Purpose This research aims to estimate the energy demand for different sectors, including commercial, industrial, residential, transportation, and agriculture. For this purpose, various factors affecting the demand for energy in each sector have been analyzed. Methodology The adopted methodology is box Jenkins a systematic approach of identification, estimation, diagnostic checks, and forecasting of the model. This model is appropriate for time series data of medium to long-term length. Findings The data analysis outcomes specified that Pakistan's energy demand mainly depends on five fuel types. Within each sector, the consumption of fuel varies. Results show that 86% of energy consumption share is held by transport oil, industrial gas, industrial coal, residential gas, and residential electricity. Conclusion The major issue in the energy sector is the demand-supply gap primarily caused by the gas and electricity deficit. Conclusively, sectoral demand increases in each sector where commercial, residential, and industrial energy demand has higher growth. Moreover, the price effect is negative for all variables except coal, making it a Giffen goo

    Energy recovery of sheep and ram wool for combustion and pyrolysis thermal processes

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    29 páginas, figuras y gráficos[ES] La problemática de residuos es uno de los principales desafíos de la sociedad actual. El sector textil contribuye notablemente de forma negativa. Este hecho es debido a que actualmente su aprovechamiento está pasando a segundo plano en detrimento de los más baratos tejidos sintéticos. Por ello, los ganaderos se centran en obtener leche o carne de sus explotaciones, mientras que la lana termina como un producto residual. Este trabajo trata los residuos procedentes de la lana de oveja y carnero. Para poder obtener un beneficio y evitar seguir contribuyendo a la generación de residuos, proponemos una recuperación energética a partir de estos desechos, contribuyendo a la economía circular a través de un proceso renovable y prometedor. El objetivo principal de este trabajo fue el de estudiar el comportamiento térmico de la lana para su aprovechamiento térmico en calderas de combustión y pirólisis. A través de una serie de análisis y tratamientos en laboratorio, obtuvimos datos específicos para oveja y carnero que derivaron en el posterior estudio termogravimétrico y cálculo de índices térmicos para cada muestra. Los resultados indicaron las buenas propiedades combustibles de las muestras analizadas, así como revelaron una mayor estabilidad térmica para la combustión de la lana de oveja y materia desprendida en el pico más representativo (31,660%/min) en relación al mismo valor del carnero (15,420 %/min). De la misma forma, para el proceso térmico de pirólisis, no existieron diferencias apreciables entre ambos tipos de lana.[EN] The waste problem is one of the main challenges of today's society. The textile sector contributes notably in a negative way. This fact is due to the fact that currently its use is passing into the background to the detriment of the cheapest synthetic fabrics. For this reason, farmers focus on obtaining milk or meat from their farms, while wool ends up as a residual product. This work deals with waste from sheep and ram wool. In order to obtain a benefit and avoid continuing to contribute to the generation of waste, we propose an energy recovery from this waste, contributing to the circular economy through a renewable and promising process. The main objective of this work was to study the thermal behaviour of wool for its thermal use in combustion and pyrolysis boilers. Through a series of laboratory analysis and treatments, we obtained specific data for sheep and ram that led to the subsequent thermogravimetric study and thermal indexes estimation. The results indicated the good combustible properties of the analysed samples, as well as revealed a greater thermal stability for the combustion of the sheep's wool and matter released in the most representative peak (31,660%/min) in relation to the same value of the ram (15,420 %/min). In the same way, for the thermal pyrolysis process, there were no appreciable differences between both types of wool

    The Effects of Salt Precipitation During CO2 Injection into Deep Saline Aquifer and Remediation Techniques

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    The by-products of combustion from the utilisation of fossil fuels for energy generation are a source of greenhouse gas emissions, mainly Carbon dioxide (CO2). This has been attributed to climate change because of global warming. Carbon capture and storage (CCS) technology has the potential to reduce anthropogenic greenhouse gas emissions by capturing CO2 from emissions sources and stored in underground formations such as depleted oil and gas reservoirs or deep saline formations. Deep saline aquifers for disposal of greenhouse gases are attracting much attention as a result of their large storage capacity. The problem encountered during CO2 trapping in the saline aquifer is the vaporisation of water along with the dissolution of CO2. This vaporisation cause salt precipitation which eventually reduces porosity and impairs the permeability of the reservoir thereby impeding the storage capacity and efficiency of the technology. Salt precipitation during CO2 storage in deep saline aquifers can have severe consequences during carbon capture and storage operations in terms of CO2 injectivity.This work investigates and assesses, experimentally, the effects of the presence of salt precipitation on the CO2 injectivity, the factors that influence them on selected core samples by core flooding experiments, and remediation of salt precipitation during CO2 injection. The investigation also covered the determination of optimum range of deep saline aquifers for CO2 storage, and the effects of different brine-saturated sandstones during CO2 sequestration in deep saline aquifers. In this investigation, three (3) different sandstone core samples (Bentheimer, Salt Wash North, and Grey Berea) with different petrophysical properties were used for the study. This is carried out in three different phases for a good presentation.‚ÄĘ Phase I of this study involved brine preparation and measurement of brine properties such as brine salinity, viscosity, and density. The brine solutions were prepared from different salts (NaCl, CaCl2, KCl, MgCl2), which represent the salt composition of a typical deep saline aquifer. The core samples were saturated with different brine salinities (5, 10, 15, 20, 25, wt.% Salt) and testing was conducted using the three selected core samples.‚ÄĘ Phase II entailed the cleaning and characterisation of the core samples by experimental core analyses to determine the petrophysical properties: porosity and permeability. Helium Porosimetry and saturation methods were used for porosity determination. Core flooding was used to determine the permeability of the core samples. The core flooding process was conducted at a simulated reservoir pressure of 1500 psig, the temperature of 45 ¬įC, with injection rates of 3.0 ml/min respectively. Interfacial tension (IFT) measurements between the CO2 and various brine salinities as used in the core flooding were also conducted in this phase. Remediation scenarios of opening the pore spaces of the core samples were carried out using the same core flooding rig and the precipitated core samples were flooded with remediation fluids (low salinity brine and seawater) under the same reservoir conditions. The petrophysical properties (Porosity, Permeability) of the core samples were measured before core flooding, after core flooding and remediation test respectively.‚ÄĘ In phase III of the study, SEM Image analyses were conducted on the core samples before core flooding, after core flooding, and remediation test respectively. This was achieved by using the FEI Quanta FEG 250 FEG high-resolution Scanning Electron Microscope (SEM) interfaced to EDAX Energy Dispersive X-ray Analysis (EDX).xivResults from Bentheimer, Salt Wash North, and Grey Berea core samples indicated a reduction in porosity, permeability impairment, as well as salt precipitation. It was also found that, at 10 to 20 wt.% brine concentrations in both monovalent and divalent brine, a substantial volume of CO2 is sequestered, which indicates the optimum concentration ranges for storage purposes. The salting-out effect was greater in divalent salt, MgCl2 and CaCl2 as compared to monovalent salt (NaCl and KCl). Porosity decreased by 0.5% to 7% while permeability was decreased by up to 50% in all the tested scenarios. CO2 solubility was evaluated in a pressure decay test, which in turn affects injectivity. Hence, the magnitude of CO2 injectivity impairment depends on both the concentration and type of salt species. The findings from this study are directly relevant to CO2 sequestration in deep saline aquifers as well as screening criteria for carbon storage with enhanced gas and oil recovery processes. Injection of remediation fluids during remediation tests effectively opened the pore spaces and pore throats of the core samples and thereby increasing the core sample's porosity in the range of 14.0% to 28.5% and 2.2% to 12.9% after using low salinity brine and seawater remediation fluids respectively. Permeability also increases in the range of 40.6% to 68.4% and 7.4% to 17.2% after using low salinity brine and seawater remediation fluids respectively. These findings provide remediation strategies useful in dissolving precipitated salt as well as decreasing the salinity of the near-well brine which causes precipitation.The SEM images of the core samples after the flooding showed that salt precipitation not only plugged the pore spaces of the core matrix but also showed significant precipitation around the rock grains thereby showing an aggregation of the salts. This clearly proved that the reduction in the capacity of the rock is associated with salt precipitation in the pore spaces as well as the pore throats. Thus, insight gained in this study could be useful in designing a better mitigation technique, CO2 injectivity scenarios, as well as an operating condition for CO2 sequestration in deep saline aquifers

    Assessing the Sustainability of Liquid Hydrogen for Future Hypersonic Aerospace Flight

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    This is the final version. Available on open access from MDPI via the DOI in this recordThis study explored the applications of liquid hydrogen (LH2) in aerospace projects, followed by an investigation into the efficiency of ramjets, scramjets, and turbojets for hypersonic flight and the impact of grey, blue, and green hydrogen as an alternative to JP-7 and JP-8 (kerosene fuel). The advantage of LH2 as a propellant in the space sector has emerged from the relatively high energy density of hydrogen per unit volume, enabling it to store more energy compared to conventional fuels. Hydrogen also has the potential to decarbonise space flight as combustion of LH2 fuel produces zero carbon emissions. However, hydrogen is commonly found in hydrocarbons and water and thus it needs to be extracted from these molecular compounds before use. Only by considering the entire lifecycle of LH2 including the production phase can its sustainability be understood. The results of this study compared the predicted Life Cycle Assessment (LCA) emissions of the production of LH2 using grey, blue, and green hydrogen for 2030 with conventional fuel (JP-7 and JP-8) and revealed that the total carbon emissions over the lifecycle of LH2 were greater than kerosene-derived fuels

    Macerals of lignite and the effect of alkali treatment on the structure and combustion performance of lignite

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    Suppressing the spontaneous combustion of lignite is of great significance for safe transportation and efficient utilization of lignite. Taking the Shengli lignite as the research object, two different macerals, inertinite and huminite, were selected by optical microscope, and treated with NaOH respectively to study the relationship between the structure and combustion reaction performance of different macerals and lignite treated with NaOH. The structure of the prepared coal samples was characterized by SEM-EDS, XPS, FT-IR, XRD and Raman, and the changes of the main functional groups were analyzed. The effect of NaOH treatment on the combustion performance of different maceral lignite was investigated by TGA. The results showed that the ignition temperature of huminite lignite was about 10 ‚ĄÉ earlier than that of inertinite, but the comprehensive combustion characteristic index of inertinite lignite was slightly higher than that of huminite. After the NaOH treatment, the lignite of different macerals showed a hysteresis of combustion, there were two obvious weight losses in the range of 200‚ąí500 ‚ĄÉ and 650‚ąí800 ‚ĄÉ, respectively, and the mass loss was mainly concentrated in the second weight loss, in particular, the effect of huminite lignite was more significant, and the temperature corresponding to the maximum combustion reaction rate was about 60 ‚ĄÉ behind that of inertinite. The kinetic analysis of the combustion process of the coal samples showed that the activation energy of combustion reaction of lignite with different macerals significantly increased after the NaOH treatment, and the huminite lignite was higher than that of inertinite lignite. The XPS/FT-IR results revealed that the contents of carboxylic oxygen-containing functional groups in different macerals of lignite treated by NaOH decreased, the main reason is that in the process of NaOH treatment, Na+ interacted with the carboxylic oxygen-containing functional groups in lignite to form the sodium carboxylate structure, and the relative amount of the sodium carboxylate structure in huminite coal was relatively large. It is believed that the inhibitory effect on the combustion of lignite with different macerals is attributed to the stability of the sodium carboxylate structure, and the number of the sodium carboxylate structure formed by combining with Na is the main reason for the difference in its combustion performance. The XRD/Raman analysis indicates that the formation of the sodium carboxylate structure in lignite leads to the increase of the order degree of carbon microcrystalline structure, and the order degree of huminite lignite is higher than that in inertinite

    Catalytic Gasification of Fine Coal Waste Using Natural Zeolite to Produce Syngas as Fuel

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    The valorisation fine coal waste is still very limited in creating energy, especially syngas. This study aims to convert fine coal waste into synthetic gas via gasification using catalyst. Fine coal gasification takes place at 350 ‚Äď 750 ¬įC in an updraft gasifier using catalyst of 12.5 ‚Äď 25 wt% natural zeolite. The research results show that the addition of zeolite has synergy with increasing temperature. The syngas produced at 750 ¬įC and 12.5 wt% zeolite consisted of 32 vol% H2, 30.1 vol% CO, 27.7 vol% CH4 and 5.1 vol% CO2. The carbon conversion efficiency and high heating value (HHV) of synthetic gas are 88.34% and 18.97 MJ/Nm¬≥. Fine coal has the potential to be reused as an energy source in the future

    Toward circularity : life cycle-based approach in waste management

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    Our current ‚Äúthrowaway‚ÄĚ lifestyle places great strain on the environment; resources that enter the economy remain for only a short period and are quickly disposed of. This dissertation aims to evaluate the economic and environmental impacts of shifting toward more circular economy (CE) practices that advocate value retention for as long as possible within the economy. The research was carried out by conceptualizing CE and solving real cases focusing on the product end-of-life (EoL) stage. Life cycle assessment (LCA) was the main tool used to assess environmental impacts of different circular scenarios. The tool was paired with life cycle costing (LCC) to evaluate economic performances. Three cases in Finland were assessed: shifting toward source-separated biowaste collection, establishing an agricultural plastics waste recycling system, and waste-to-energy optimization. It was found that CE covers multiple aspects within the value chain; thus, its adoption model can occur at any stage of the value chain, thereby enabling various stakeholders to be more circular through different actions. The cases suggested that being more circular at the EoL stage may improve value retention through secondary material production, waste treatment by-products, and energy recovery. Shifting toward circularity was shown to be economically and environmentally viable. The dissertation illustrated the importance of stakeholders‚Äô collaboration because a circular approach could affect all actors within the supply chain, including manufacturing, the energy sector, and society. The study showed that it is important to quantify environmental impacts of products or services, and to date, LCA remains the most suitable tool for quantifying results and evaluating options. In addition, a combination with LCC will provide more comprehensive results to anticipate any trade-off between environmental and economic aspects. CE must start somewhere, so let it start with organizations evaluating their environmental performance to identify better alternatives, define targets, and foster circularity in the long run.Nykyinen kertak√§ytt√∂el√§m√§ntapa aiheuttaa painetta ymp√§rist√∂lle. Monia raaka-aineita, joita k√§ytet√§√§n taloudessa, hy√∂dynnet√§√§n vain lyhyen aikaa ja h√§vitet√§√§n nopeasti. T√§m√§n v√§it√∂skirjan tavoitteena on arvioida taloudellisia ja ymp√§rist√∂vaikutuksia yritysten siirtymisess√§ kohti kiertotalouden (CE) k√§yt√§nt√∂j√§, joiden avulla pyrit√§√§n arvon s√§ilytt√§miseen mahdollisimman pitk√§√§n. Tutkimus toteutettiin tarkastelemalla kiertotalouden k√§sitteit√§ ja esitt√§m√§ll√§ ratkaisumalleja tapaustutkimuksiin, joissa keskityttiin tuotteen elinkaaren loppuvaiheeseen (EoL). Elinkaariarviointi (LCA) oli n√§iss√§ t√§rkein ty√∂kalu erilaisten kiertoskenaarioiden ymp√§rist√∂vaikutusten arvioinnissa. T√§m√§ ty√∂kalu yhdistettiin elinkaarikustannuslaskentaan (LCC) taloudellisen suorituskyvyn arvioimiseksi. Kolme tapaustutkimusta toteutettiin Suomessa: (1) siirtyminen bioj√§tteen lajitteluker√§ykseen, (2) maatalouden muovij√§tteen kierr√§tysj√§rjestelm√§n suunnittelu ja (3) j√§tteen energian optimointi. Tulokset osoittivat, ett√§ kiertotalouden avulla voidaan kattaa useita arvoketjun n√§k√∂kohtia; k√§ytt√∂√∂notto voidaan toteuttaa mill√§ tahansa arvoketjun tasolla, ja eri sidosryhm√§t voivat lis√§t√§ kiertoa eri toimien kautta. Tulokset viittaavat siihen, ett√§ kierron lis√§√§minen EoL-vaiheessa voisi parantaa arvon s√§ilytt√§mist√§ uusiomateriaalituotannon, j√§tteenk√§sittelyn sivutuotteiden ja energian talteenoton avulla. Tyyppitapausten perusteella yritysten siirtyminen kiertotalousk√§yt√§nt√∂ihin osoittautui sek√§ taloudellisesti ja ymp√§rist√∂n kannalta kannattavaksi. Ty√∂n tulokset ovat havainnollistaneet sidosryhmien yhteisty√∂n t√§rkeytt√§. Kierron rakentaminen voi vaikuttaa kaikkiin toimitusketjun toimijoihin, mukaan lukien valmistus, energiantuotanto ja yhteiskunta laajemmin. Tutkimus osoitti, ett√§ tuotteiden tai palveluiden ymp√§rist√∂vaikutusten kvantitatiivinen mittaaminen on t√§rke√§√§, ja LCA on edelleen sopivin v√§line tulosten kvantifiointiin ja erilaisten vaihtoehtojen keskin√§iseen arviointiin. Elinkaarilaskelmaan yhdistettyn√§ elinkaarikustannuslaskentaan saadaan aikaan kattavampia tuloksia, joilla voidaan vertailla ymp√§rist√∂- ja talousn√§k√∂kohtien mahdollisia ristiriitoja. Kiertotalousty√∂ on aloitettava jostain, ja se voi alkaa siit√§, ett√§ organisaatiot mittaavat ymp√§rist√∂tehokkuuttaan rakentaakseen parempia vaihtoehtoja, m√§√§ritell√§kseen tavoitteitaan ja edist√§√§kseen kiertojen kehittymist√§ pitk√§ll√§ aikav√§lill√§.fi=vertaisarvioitu|en=peerReviewed
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