Progress in Energy and Combustion Science最新文献

Various energetic materials, including solid rocket propellants, have found numerous applications in aerospace technology in the past decades. This growing interest initiated an increasing number of experimental and technological studies, leading to a wide range of published experimental data. Due to the intrinsic challenges of data acquisition and processing, assessing the accuracy of the measurement results is important. In this paper, a review of existing experimental techniques for measuring the regression rate of energetic materials is presented along with a description of the fundamental physical principles used for developing the particular methods. Special attention is paid to recent developments in measurements of highly-dynamic processes. Technical requirements for correct determination of regression rate are analyzed focusing on the methods associated with transient combustion. Emphasis is placed on laboratory-scale methods intended to obtain correct and reliable data on regression rate in well-characterized environments that can be used for comparison with theoretical predictions. The measurement methods are divided into direct and indirect ones. It is shown that direct high-speed photography could not be effectively used for recording regression rate oscillations with frequencies higher than 30–50 Hz. The same limitation applies to classical ultrasound techniques and X-ray radiography. However, radiography techniques based on synchrotron and terahertz radiation are promising. Special attention is paid to development of microwave and laser recoil methods that provide high spatial and temporal resolution capable of correctly determining transient regression rate.

Sensors are perhaps the most important and integral components of our modern society. With global warming and environmental pollution garnering ever-increasing attention, as well as solutions for sustainabile and smart cities, the optimized performance of current and future energy systems and process industries is paramount. The accurate sensing and quantification of key parameters of such systems are essential for monitoring, controlling, and optimization efforts. In situ laser-based optical sensors are most suitable for achieving the desired characteristics of accuracy, sensitivity, selectivity, portability, speed, safety, and intelligence. In recent decades, significant progress has been made in the development and deployment of laser-based sensing solutions, although new challenges and opportunities continue to emerge rapidly. In this review paper, we focus on laser absorption spectroscopy (LAS)-based sensors owing to their simple architecture, easy implementation, and market penetration. We detail recent advancements made in LAS variants using new laser sources and techniques. A brief discussion on other laser-based sensing techniques, namely, photoacoustic spectroscopy, laser-induced fluorescence, coherent anti-Stokes Raman spectroscopy, and laser-induced breakdown spectroscopy, is provided to compare these strategies with LAS. The applications of laser-based sensors in various energy systemsincluding engines, turbines, power plants, furnaces, and boilers—as well as process industriessuch as petrochemical, semiconductor, natural gas leak detection, and corrosion detectionare presented, illustrating their many benefits and possible uses. A distinguishing aspect of this review paper is that we present the comparison of previous studies in tabular formats, making it easy to appreciate the recent progress in laser-based sensing solutions. Finally, suggestions on future directions and emerging technologies to pursue for the further enhancement, development, and deployment of laser-based sensors are proposed.

The IPCC recommends keeping the global average temperature increase well below 2 °C, if not below 1.5 °C, by 2100 to avoid the worst effects of climate change. This requires achieving carbon neutrality shortly after 2050. In the United States, industrial emissions represent 22% of greenhouse gas emissions and are particularly hard to decarbonize, because (1) the processes emit CO₂ as a byproduct of chemical reactions and (2) these industries require high-grade heat input. This study focuses on some of these industries, namely cement, lime, glass, and steelmaking. This work details the incumbent kiln and furnace technologies and explores the developing processes with examples of existing projects that aim to reduce carbon emissions, such as carbon capture and storage (CCS), fuel switching, and other technological changes. We provide tools to evaluate the most appropriate low-carbon solutions at existing facilities and on new-build infrastructure while taking into account the local context and resources.

This paper highlights two states within the U.S. with a high concentration of cement, lime, glass, and steelmaking facilities, California and Pennsylvania. The emissions from cement, lime, and glass facilities in California total 8.5 MtCO₂eq/yr. About 6.3 MtCO₂/yr (7.1% of in-state industrial emissions) could be captured from cement and lime facilities, transported, and stored in sedimentary basins below the Central Valley. Replacing 20% of coal by biomass could also reduce the fossil emissions by 0.5 MtCO₂/yr (6.2% of in-state industrial emissions) without making changes to the facilities. In Pennsylvania, heavy industry (cement, lime, glass, and steelmaking) emits about 9.4 MtCO₂eq/yr. Most of the facilities are located near sedimentary basins, facilitating the development of CCS. In addition, the presence of low-carbon energy sources can help in the deployment of electrified processes. Also, industrial byproducts such as steel slag and fly ash can be reused in low-carbon concrete mix. As shown with these two examples, there are many strategies leading to the deep decarbonization of the economy and they need to be adapted to the local context.

Gas-solid fluidized beds have drawn the attention of engineers and researchers as an effective technology for a large variety of applications, and numerical simulations can play an increasingly relevant role in their development and optimization. Although real-time simulations will require substantial progress in the accuracy, capability, and efficiency of numerical models, future developments could herald a new era of so-called virtual reality for process engineering, featuring interactive simulations instead of stepwise experimental scale-up studies and cost-intensive empirical trial-and-error methods. This review paper provides a significant body of knowledge on the developments of CFD mathematical models and how they can be applied in various fluidized-bed systems. The review is divided into three main parts. The first part (Mathematical modeling) describes the state-of-the-art numerical models of gas-solid flows (two-fluid model, soft-sphere model, hard-sphere model, and hybrid model) and their fundamental assumptions (gas-solid, particle-particle, and particle-wall interactions). Special attention is devoted to the forces and the moments of the forces acting on particles, the parcel modeling, the homogeneous and structure-dependent drag models, the non-spherical particle models, the heat and mass transfer, and the turbulence. The second part of this review (State-of-the-art studies) is dedicated to the body of literature, focusing on how these numerical models are applied to fluidized-bed systems used in chemical and energy process engineering. Relevant works on simulation in the literature up to 2021 are analyzed, complemented by an overview of popularly used commercial and in-house simulation codes. Particular attention is paid to those studies that include measurement validation, to achieve a fundamentally competitive comparison between the different numerical models. The pros and cons of applying CFD models to fluidized-bed systems are studied and assessed based on the existing body of literature. The third part of this review (Conclusion and prospects) highlights current research trends, identifying research gaps and opportunities for future ways, in which CFD can be applied to fluidized beds for energetic and chemical processes.

Fast gas heating (FGH) is an abrupt increase in gas temperature in non-equilibrium low-temperature plasma due to relaxation of electronically excited states of atoms and molecules. In the active flow control, fast gas heating is responsible for thermal frequency perturbations in the range of unstable frequencies of flow instabilities. In plasma-assisted combustion, abrupt temperature increase due to FGH, together with generation of radicals in plasma, induces acceleration of combustion chemistry providing shortening of the induction delay time and intensification of combustion. Over the last decade, significant progress has been made towards the understanding of kinetics of the fast gas heating. New observations of fast gas heating in air and nitrogen/oxygen mixtures have been reported. The result of experiments, reporting heating to thousands of kelvins during tens of nanoseconds at atmospheric pressure in non-combustible mixtures, have provided new opportunities in the development of kinetic models. Electron-impact dissociation, quenching of electronically excited states of atoms and molecules, ion-molecular reactions, recombination of charged particles are reviewed analysing their role in the fast gas heating. The fraction of energy spent on fast gas heating η_R has been suggested as a universal parameter to generalize the results of empirical research on energy relaxation. This paper considers the dependence of η_R on reduced electric field, specific delivered energy, oxygen fraction in the mixture and other parameters. The analysis is grouped over three different ranges of the reduced electric field: E/N ≤ 150 Td, E/N = 150–400 Td and E/N > 400 Td. Non-numerous experimental and theoretical studies of the fast gas heating in hydrogen- and hydrocarbon-containing mixtures are discussed and compared to the results in non-flammable mixtures. This article is to provide a comprehensive overview of the progress of kinetics of fast gas heating and to indicate the lack of experimental data and consequently, the gap in the knowledge of energy relaxation in discharges in combustible mixtures.

Laser-based methodologies for synthesis, reduction, modification and assembly of graphene-based materials are highly demanded for energy-related electrodes and devices for portable electronics. Laser technologies for graphene synthesis and modification exhibit several advantages when compared to alternative methods. They are fast, low-cost and energy saving, allowing selective heating and programmable processing, with controlled manipulation over the main experimental parameters. In this review, we summarize the most recent studies on laser-assisted synthesis of graphene-based materials, as well as their modification and application as electrodes for supercapacitor and battery applications. After a brief introduction to the physical properties of graphene and a discussion of the different types of laser processing operations, the practical uses of laser techniques for the fabrication of electrode materials are discussed in detail. Finally, the review is concluded with a brief discussion of some of the outstanding problems and possible directions for research in the area of laser-based graphene materials for energy storage devices.

Deployment of fossil fuels to quench the energy demand of the world's rising population results in elevated levels of greenhouse gas (GHG) emissions, especially CO₂, which in turn is responsible for undesirable climate change. This necessitates a shift toward cleaner energy resources such as hydrogen. Enhanced hydrogen production via steam reforming of diverse fuels (methane, biomass, organic wastes, etc.) with in-situ CO₂-sorption seems to be a promising alternative. Leading-edge, innovative and eco-friendly pathways coupled with high process efficiencies are needed for the development and growth of this technology. This review article evaluates the fundamental concepts such as criteria for CO₂ uptake, mechanisms, thermodynamics and kinetics of the water gas shift reaction along with different modeling methods for sorption enhanced processes. Moreover, research works carried out worldwide at lab-scale coupled with process development and demonstration units are discussed as a means to encourage this pathway for H₂ generation. Furthermore, light is shed on techno-economics as an approach to improve the viability and sustainability of the proposed technology. This paper analyzes different dimensions of the CO₂-sorption enhanced process to promote it as a potentially carbon-neutral and eco-friendly pathway for hydrogen production.