Iskanje po katalogu digitalne knjižnice

Opis: How to evaluate the fuel gas operation (FGO) of various working groups (WGs) and working shifts (WSs) in reheating furnace is still ambiguous problem. In this paper, a novelty time-series FGO evaluation model was proposed. The strategy mainly included: Firstly, the fuel gas per ton steel (FGTS) was calculated in certain time interval; Secondly, the FGTS time-series data set was formulated in statistical period; Thirdly, the FGTS time-series data set was divided according to working schedule; Lastly, the FGO evaluation model was established. Case study showed that: i) The fuel gas operation evaluation results of various WGs in different WSs were accorded with normal distribution; ii) For various WGs, A WG performed best, followed by C WG and D WG. The performance of B WG was the worst due to its violent fluctuation of fuel gas operation evaluation results in three WSs; iii) For different WSs, the day WS and swing WS performed well, whereas the performance of night WS was unsatisfactory. Discussion results showed that the improvement of working skills, working responsibility and working passion, which were effective measure to achieve energy saving in terms of operation, should be enhanced through skills training and the reward and punishment system. Generally, this novelty time-series FGO evaluation method could also be applied to other industrial equipment.
Ključne besede: Iron industry, steel Industry, fuel gas operation management, FGO evaluation model, reheating furnace, fuel gas per ton steel time-series, working groups
Objavljeno v DKUM: 15.01.2026; Ogledov: 0; Prenosov: 0
Celotno besedilo (993,34 KB)
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Opis: Energy is an essential component of our daily lives. Despite the expanded use of new and renewable energy sources, oil and gas remain the primary sources of energy. Recently, oil and gas sources have become more vulnerable due to their limited and uncertain availability, as well as geopolitical issues that threaten the security of their supply chains. As a result, securing energy sources in general and oil and gas in particular at reasonable prices and reliable supplies has become a major global concern. As a result, the establishment and operation of energy hubs along energy transit routes between producing and consuming countries is crucial for the security and sustainability of the energy supply. These energy hubs can facilitate the trade and exchange of energy by offering logistics services such as transportation, storage, processing, and distribution. This means that establishing and operating such energy hubs necessitates some logistics requirements. However, previous studies did not tackle the logistics requirements for establishing and operating energy hubs in a single, comprehensive framework. Accordingly, the purpose of this study is to address the logistics requirements of energy hubs, with a focus on oil and gas, and to develop a comprehensive framework for establishing and operating GLEH through conducting an empirical study on the Egyptian oil and gas industry. The study was carried out through seven sequential phases. The study conducted a systematic review of the previous literature using the PRISMA flow diagram and visual bibliometric analysis via VOSviewer software to identify the main research gap and develop an integrated theoretical framework for creating and operating a GLEH. The study then adopted mixed research methods to reap the benefits of both qualitative and quantitative methods. The qualitative technique was used to convert the theoretical framework into a practical framework by conducting semi-structured interviews with key stakeholders. The quantitative method was applied to examine the relationships between the variables and validate the study’s hypotheses in the Egyptian context through a survey. The study set out an applied framework to help establish and operate GLEHs that can improve the security of energy supplies. It also highlighted the key challenges that might face the establishment and operation of GLEHs and suggested strategies to deal with them. The study would contribute to science by developing a unique and comprehensive framework for establishing and operating GLEHs, considering both theoretical and empirical aspects. At a practical level, the proposed framework can help improve the global energy supply chain and its sustainability, especially for oil and gas. It can also be used as a model by other countries and regions to establish and operate logistics hubs for energy and other sectors. Furthermore, the framework can be used in further research to develop the performance of energy hubs.
Ključne besede: Energy supply chain, energy sustainability and security, global logistics energy hub, oil and gas, Egypt
Objavljeno v DKUM: 27.08.2025; Ogledov: 0; Prenosov: 13
Celotno besedilo (9,35 MB)

Opis: More energy-efficient industries could reduce the problems of pollution, global warming, energy security, and fossil fuel depletion, including processing waste into raw materials and more efficient energy cogeneration. This research project considers the novelties of the upgraded electricity cogeneration technique, including one open gas turbine during the high-pressure product reaction loop and a second turbine during the exhaust gas for co-product production with only one compressor. The upgraded electricity cogeneration was carried out in two steps and based on the productive use of otherwise useless polyethylene waste, flue gas, and wood. The first step can simulate the simulation model from the existing product production with well-known technology and process units using the Aspen Plus® simulator. The maximum available electricity cogeneration can previously be determined from the thermodynamics of the products and co-products, and an existing energy unit’s characteristic capacity. In the second step, conventional natural gas can be replaced with waste as the raw materials by using the same simulated model from the first step, including electricity cogeneration using the gas turbines during the high-pressure reaction loop, and the exhaust gas as the co-product with only one compressor. This research on electricity generation is based on processes that include the pressure drop during the product reaction loop. This approach is illustrated using an existing methanol production process, using wastes as sustainable raw materials, including electricity cogeneration during the reaction loop and exhaust gas, generating a possible increase in annual profit of 7.28 MEUR/a.
Ključne besede: waste recovery, cogeneration, exothermic reactor, gas turbine, exhaust gas, combined compressor
Objavljeno v DKUM: 15.05.2025; Ogledov: 0; Prenosov: 8
Celotno besedilo (1,06 MB)
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Opis: Despite the advantages of polylactide (PLA), its inadequate UV-shielding and gas-barrier properties undermine its wide application as a flexible packaging film for perishable items. These issues are addressed in this work by investigating the properties of melt-mixed, fully bioderived blends of polylactide (PLA) and poly(ethylene furanoate) (PEF), as a function of the PEF weight fraction (1–30 wt %) and the amount of the commercial compatibilizer/chain extender Joncryl ADR 4468 (J, 0.25–1 phr). J mitigates the immiscibility of the two polymer phases by decreasing and homogenizing the PEF domain size; for the blend containing 10 wt % of PEF, the PEF domain size drops from 0.67 ± 0.46 µm of the uncompatibilized blend to 0.26 ± 0.14 with 1 phr of J. Moreover, the increase in the complex viscosity of PLA and PLA/PEF blends with the J content evidences the effectiveness of J as a chain extender. This dual positive contribution of J is reflected in the mechanical properties of PLA/PEF blends. Whereas the uncompatibilized blend with 10 wt % of PEF shows lower mechanical performance than neat PLA, all the compatibilized blends show higher tensile strength and strain at break, while retaining their high elastic moduli. The effects of PEF on the UV- and oxygen-barrier properties of PLA are also remarkable. Adding only 1 wt % of PEF makes the blend an excellent barrier for UV rays, with the transmittance at 320 nm dropping from 52.8% of neat PLA to 0.4% of the sample with 1 wt % PEF, while keeping good transparency in the visible region. PEF is also responsible for a sensible decrease in the oxygen transmission rate, which decreases from 189 cc/m2 ·day for neat PLA to 144 cc/m2 ·day with only 1 wt % of PEF. This work emphasizes the synergistic effects of PEF and J in enhancing the thermal, mechanical, UV-shielding, and gas-barrier properties of PLA, which results in bioderived blends that are very promising for packaging applications.
Ključne besede: polylactide, furanoates, poly(ethylene furanoate), blends, compatibilization, gas-permeability, UV-shielding
Objavljeno v DKUM: 24.03.2025; Ogledov: 0; Prenosov: 9
Celotno besedilo (4,33 MB)
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Opis: This article presents an all-fiber, miniature Fabry-Perot gas sensor based on photothermal absorption spectroscopy with a custom-made and cost-efficient interrogation system. The sensing gas microcell has a diameter of 125 μ m and a length of 1 mm, and allows for free gas exchange within the optical resonator through micromachined slits. High light intensity and confinement are ensured by delivering the excitation light directly into the gas microcell through a lead-in single-mode fiber. This enhances the photothermal effect and provides a short system response time. The interrogation system utilizes the modulation of an excitation laser diode with a fixed frequency while locking the probe laser onto the gas microcell’s quadrature point (QP) and observing the variations of the reflected optical power. To show the potential of the proposed system, nitrogen dioxide (NO2 was measured in dry air. Thereby, a limit of detection of 20 ppm could be achieved for 10 s integration time. Furthermore, the small dimensions of the sensor allow for improved dynamic performance with photothermal modulation frequencies as high as 7 kHz.
Ključne besede: Fabry–Perot interferometer, FPI, fiber gas cell, fiber gas sensor, nitrogen dioxide, NO2, photothermal effect
Objavljeno v DKUM: 29.08.2024; Ogledov: 96; Prenosov: 33
Celotno besedilo (15,77 MB)
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