Pub Date : 2024-11-13DOI: 10.1016/j.energy.2024.133805
Boqiang Lin, Zhiwei Liu
The use of renewable energy sources (RES) is expected to increase, potentially leading to volatility in the power system. Therefore, flexible power is essential to address this challenge. In China, two viable options for providing flexible power are battery energy storage systems (BESS) and flexibility modification of coal power units. This study introduces a framework to evaluate the costs of power system flexibility under varying RES shares on an hourly basis, comparing flexible coal power and BESS across several scenarios. In the short term, flexible coal power proves to be more advantageous than BESS, but BESS shows greater promise in the long run. The study suggests that while coal power will continue to play a critical role in the near future, it should gradually be phased out by reducing its utilization hours. Meanwhile, BESS should receive greater focus for long-term energy strategy. This study underscores the importance of maintaining power system stability throughout the low-carbon transition and highlights the need to balance short-term and long-term strategies for flexible power.
{"title":"Assessment of flexible coal power and battery energy storage system in supporting renewable energy","authors":"Boqiang Lin, Zhiwei Liu","doi":"10.1016/j.energy.2024.133805","DOIUrl":"10.1016/j.energy.2024.133805","url":null,"abstract":"<div><div>The use of renewable energy sources (RES) is expected to increase, potentially leading to volatility in the power system. Therefore, flexible power is essential to address this challenge. In China, two viable options for providing flexible power are battery energy storage systems (BESS) and flexibility modification of coal power units. This study introduces a framework to evaluate the costs of power system flexibility under varying RES shares on an hourly basis, comparing flexible coal power and BESS across several scenarios. In the short term, flexible coal power proves to be more advantageous than BESS, but BESS shows greater promise in the long run. The study suggests that while coal power will continue to play a critical role in the near future, it should gradually be phased out by reducing its utilization hours. Meanwhile, BESS should receive greater focus for long-term energy strategy. This study underscores the importance of maintaining power system stability throughout the low-carbon transition and highlights the need to balance short-term and long-term strategies for flexible power.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133805"},"PeriodicalIF":9.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.energy.2024.133818
Hang Lv , Qiong Wu , Hongbo Ren , Qifen Li , Weisheng Zhou
Extreme natural disasters are occurring with increasing frequency worldwide, posing unprecedented challenges to urban energy systems. In this study, an evolutionary game approach is employed to examine the interactive behavior among the grid, virtual power plant operators, and users, focusing on enhancing the resilience of urban energy systems. The impact of long-term power system development on the simulation outcomes has been examined. Key parameters in the game model are determined through numerical simulation. The evolutionary stabilization strategies of individual actors and the system have been analyzed holistically. According to the simulation results, as the benefit per unit of load restoration increases from 40 to 1000, all three parties increasingly prioritize resilience in their decision-making processes. Notably, when the benefit per unit of load restoration is 40, grid firms tend to disregard resilience. To enhance power system resilience, especially in the context of a high percentage of renewable energy generation, the utility grid should prioritize managing the integration of renewable energy into the grid. Moreover, there is a growing public interest in participating in dynamic demand response programs for incentives. In addition, within certain parameters, the objective of increasing renewable energy consumption may conflict with the aim of improving power system resilience. Virtual power plant operators are unlikely to introduce new renewable energy projects if the return is below 0.0325 Yuan/kWh. This study may offer strategic recommendations for enhancing long-term power system resilience, providing valuable insights for practical and realistic planning.
{"title":"Collaborative strategy towards a resilient urban energy system: Evidence from a tripartite evolutionary game model","authors":"Hang Lv , Qiong Wu , Hongbo Ren , Qifen Li , Weisheng Zhou","doi":"10.1016/j.energy.2024.133818","DOIUrl":"10.1016/j.energy.2024.133818","url":null,"abstract":"<div><div>Extreme natural disasters are occurring with increasing frequency worldwide, posing unprecedented challenges to urban energy systems. In this study, an evolutionary game approach is employed to examine the interactive behavior among the grid, virtual power plant operators, and users, focusing on enhancing the resilience of urban energy systems. The impact of long-term power system development on the simulation outcomes has been examined. Key parameters in the game model are determined through numerical simulation. The evolutionary stabilization strategies of individual actors and the system have been analyzed holistically. According to the simulation results, as the benefit per unit of load restoration increases from 40 to 1000, all three parties increasingly prioritize resilience in their decision-making processes. Notably, when the benefit per unit of load restoration is 40, grid firms tend to disregard resilience. To enhance power system resilience, especially in the context of a high percentage of renewable energy generation, the utility grid should prioritize managing the integration of renewable energy into the grid. Moreover, there is a growing public interest in participating in dynamic demand response programs for incentives. In addition, within certain parameters, the objective of increasing renewable energy consumption may conflict with the aim of improving power system resilience. Virtual power plant operators are unlikely to introduce new renewable energy projects if the return is below 0.0325 Yuan/kWh. This study may offer strategic recommendations for enhancing long-term power system resilience, providing valuable insights for practical and realistic planning.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133818"},"PeriodicalIF":9.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.energy.2024.133814
Kun Su , Ziqu Ouyang , Shuyun Li , Qisi Chen , Hongshuai Wang , Hongliang Ding , Wenyu Wang
Under the strategic objectives of carbon peaking and carbon neutrality, increasingly stringent NOx emission standard was hard to meet in coal-fired boilers, and it was imperative to develop clean coal combustion technologies. As a novel combustion technology, purifying-combustion technology had good prospects in NOx emission reduction, and pulverized coal modification and modified fuel combustion occurred in purifying burner and down-fired combustor (DFC) respectively with this technology. The novelty of this study was associated with a first-time systematical analysis of the advantage of purifying burner in deep pulverized coal activation and the matching relationship of multistage combustion air in reduction region of DFC. Experiments were performed in 30 kW purifying-combustion test rig to investigate the two-stage modification characteristics of pulverized coal in purifying burner and the difference in influence of reducing intensity on combustion and NOx emission characteristics at different reduction region lengths and the influence of staged air distribution on them in DFC. Two-stage purifying burner demonstrated greater advantages in improving particle properties of pulverized coal compared to single-stage self-preheating burner: specific surface area, pore volume, pore diameter, density of carbon defect structure and fuel-N conversion rate increased from 19.01 m3/g, 29.15 mm3/g, 4.34 nm, 3.93 and 52.96 % to 34.39 m3/g, 42.49 mm3/g, 4.57 nm, 4.41 and 66.43 %, respectively. In DFC, increasing reducing intensity in reduction region or extending its length reduced NOx emission, albeit at the expense of combustion efficiency (η). Decreasing reducing intensity resulted in decrease of η difference and increase of NOx emission difference between different lengths. Staged air distribution in reduction region promoted clean and efficient combustion, and increasing staged air ratio to ∞ realized minimal NOx emission of 39.50 mg/m3 with η of 99.23 %.
{"title":"Exploration on deep pulverized coal activation and ultra-low NOx emission strategies with novel purifying-combustion technology","authors":"Kun Su , Ziqu Ouyang , Shuyun Li , Qisi Chen , Hongshuai Wang , Hongliang Ding , Wenyu Wang","doi":"10.1016/j.energy.2024.133814","DOIUrl":"10.1016/j.energy.2024.133814","url":null,"abstract":"<div><div>Under the strategic objectives of carbon peaking and carbon neutrality, increasingly stringent NO<sub><em>x</em></sub> emission standard was hard to meet in coal-fired boilers, and it was imperative to develop clean coal combustion technologies. As a novel combustion technology, purifying-combustion technology had good prospects in NO<sub><em>x</em></sub> emission reduction, and pulverized coal modification and modified fuel combustion occurred in purifying burner and down-fired combustor (DFC) respectively with this technology. The novelty of this study was associated with a first-time systematical analysis of the advantage of purifying burner in deep pulverized coal activation and the matching relationship of multistage combustion air in reduction region of DFC. Experiments were performed in 30 kW purifying-combustion test rig to investigate the two-stage modification characteristics of pulverized coal in purifying burner and the difference in influence of reducing intensity on combustion and NO<sub><em>x</em></sub> emission characteristics at different reduction region lengths and the influence of staged air distribution on them in DFC. Two-stage purifying burner demonstrated greater advantages in improving particle properties of pulverized coal compared to single-stage self-preheating burner: specific surface area, pore volume, pore diameter, density of carbon defect structure and fuel-N conversion rate increased from 19.01 m<sup>3</sup>/g, 29.15 mm<sup>3</sup>/g, 4.34 nm, 3.93 and 52.96 % to 34.39 m<sup>3</sup>/g, 42.49 mm<sup>3</sup>/g, 4.57 nm, 4.41 and 66.43 %, respectively. In DFC, increasing reducing intensity in reduction region or extending its length reduced NO<sub><em>x</em></sub> emission, albeit at the expense of combustion efficiency (<em>η</em>). Decreasing reducing intensity resulted in decrease of <em>η</em> difference and increase of NO<sub><em>x</em></sub> emission difference between different lengths. Staged air distribution in reduction region promoted clean and efficient combustion, and increasing staged air ratio to ∞ realized minimal NO<sub><em>x</em></sub> emission of 39.50 mg/m<sup>3</sup> with <em>η</em> of 99.23 %.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133814"},"PeriodicalIF":9.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.energy.2024.133811
Yunge Zou , Yalian Yang , Yuxin Zhang , Changdong Liu
The powertrain configuration, sizing, and control are multi-dimensional intertwined. Synergy optimization of these three dimensions can yield the greatest benefits. However, the huge computational load limits its implementation. Especially for multi-modes and multi-gears (MMMG) transmissions. Thus, a more efficient optimization method with acceptable accuracy is urgently required. In this study, a near-global optimal method, called Hyper-Rapid Dynamic Programming (HR-DP), is proposed and discussed. The computation time is significantly reduced by optimization of candidate state and control domains, identification of optimal efficiency operating points, and parallel computation approaches. Subsequently, a thorough comparison of the HR-DP, Rapid-DP and DP methods was performed across various driving cycles. Compared to the DP algorithm, the computational efficiency is boosted by a factor of about 100,000, while the fuel consumption error is limited to 1.5 % in Real-world driving cycle (RWDC). Moreover, the HR-DP, in conjunction with particle swarm optimization (PSO), is employed for the first time to optimize essential sizing for MMMG configuration. The MMMG configuration with optimal sizing is demonstrated to be most energy-efficient, with 7.70%–10.6 % fuel-savings achieved, compared to the Toyota Prius. Therefore, HR-DP is well-suited for the design and optimization of HEV transmission configurations and sizing, significantly accelerating the development progress.
{"title":"Computationally efficient assessment of fuel economy of multi-modes and multi-gears hybrid electric vehicles: A hyper rapid dynamic programming approach","authors":"Yunge Zou , Yalian Yang , Yuxin Zhang , Changdong Liu","doi":"10.1016/j.energy.2024.133811","DOIUrl":"10.1016/j.energy.2024.133811","url":null,"abstract":"<div><div>The powertrain configuration, sizing, and control are multi-dimensional intertwined. Synergy optimization of these three dimensions can yield the greatest benefits. However, the huge computational load limits its implementation. Especially for <em>multi-modes and multi-gears</em> (MMMG) transmissions. Thus, a more efficient optimization method with acceptable accuracy is urgently required. In this study, a near-global optimal method, called <em>Hyper-Rapid Dynamic Programming</em> (HR-DP), is proposed and discussed. The computation time is significantly reduced by optimization of candidate state and control domains, identification of optimal efficiency operating points, and parallel computation approaches. Subsequently, a thorough comparison of the HR-DP, Rapid-DP and DP methods was performed across various driving cycles. Compared to the DP algorithm, the computational efficiency is boosted by a factor of about 100,000, while the fuel consumption error is limited to 1.5 % in Real-world driving cycle (RWDC). Moreover, the HR-DP, in conjunction with particle swarm optimization (PSO), is employed for the first time to optimize essential sizing for MMMG configuration. The MMMG configuration with optimal sizing is demonstrated to be most energy-efficient, with 7.70%–10.6 % fuel-savings achieved, compared to the Toyota Prius. Therefore, HR-DP is well-suited for the design and optimization of HEV transmission configurations and sizing, significantly accelerating the development progress.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133811"},"PeriodicalIF":9.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.energy.2024.133782
Magdalena Skrzyniarz , Marcin Sajdak , Anna Biniek-Poskart , Andrzej Skibiński , Artur Maroszek , Paweł Niegodajew , Monika Zajemska
The paper presents some benefits that can be gained in the metallurgical industry from utilizing pyrolysis gas obtained from biomass and plastic waste, in particular in a pusher type reheating furnace. The typical fuel composition that normally involves a mixture of natural gas and coke oven gas was modified by introducing a 9–16 % share of pyrolysis gas. The materials used in the production of the pyrolysis gas were alder and pine chips, as well as polypropene waste. For all these materials, the contents of carbon, hydrogen, nitrogen, sulfur and oxygen were experimentally estimated on a test stand for solid fuel conversion in a stationary bed at the temperature of 600 °C. The design capacity of the furnace was 90 t/h and the installed power of the furnace was 72.3 MW. Based on data gained from the rolling mill of a steel mill located in Poland, analysis of the profitability of using pyrolysis gas for co-combustion with coke oven gas and natural gas in an industrial heating furnace was carried out. As a result, a significant benefit can be achieved, namely reduced production costs of the analyzed steel company by utilizing pyrolysis gas, leading to an increase in the attractiveness of the plant's products. Plastic waste and biomass are employed as energy sources in the suggested technology, therefore using them as feedstock for the pyrolysis reactor combined with the pusher type metallurgical reheating furnace is a potential proposal for the future.
本文介绍了在冶金工业中利用从生物质和塑料废料中获得的热解气体所能带来的一些益处，特别是在推杆式再加热炉中。典型的燃料成分通常包括天然气和焦炉煤气的混合物，通过引入 9-16% 的热解气体，对这种燃料成分进行了改良。用于生产热解气体的材料有桤木和松木屑，以及聚丙烯废料。所有这些材料的碳、氢、氮、硫和氧含量都是在 600 °C 固定床固体燃料转化试验台上通过实验估算出来的。该炉的设计产能为 90 吨/小时，装机功率为 72.3 兆瓦。根据从波兰一家钢厂的轧钢厂获得的数据，对在工业加热炉中使用热解气体与焦炉煤气和天然气共燃的盈利能力进行了分析。分析结果表明，利用热解气体可以获得巨大收益，即降低被分析钢铁公司的生产成本，从而提高工厂产品的吸引力。在建议的技术中，塑料废料和生物质被用作能源，因此，将它们用作热解反应器的原料并与推杆式冶金再加热炉相结合是未来的一个潜在建议。
{"title":"Economic benefits for the metallurgical industry from co-combusting pyrolysis gas from waste","authors":"Magdalena Skrzyniarz , Marcin Sajdak , Anna Biniek-Poskart , Andrzej Skibiński , Artur Maroszek , Paweł Niegodajew , Monika Zajemska","doi":"10.1016/j.energy.2024.133782","DOIUrl":"10.1016/j.energy.2024.133782","url":null,"abstract":"<div><div>The paper presents some benefits that can be gained in the metallurgical industry from utilizing pyrolysis gas obtained from biomass and plastic waste, in particular in a pusher type reheating furnace. The typical fuel composition that normally involves a mixture of natural gas and coke oven gas was modified by introducing a 9–16 % share of pyrolysis gas. The materials used in the production of the pyrolysis gas were alder and pine chips, as well as polypropene waste. For all these materials, the contents of carbon, hydrogen, nitrogen, sulfur and oxygen were experimentally estimated on a test stand for solid fuel conversion in a stationary bed at the temperature of 600 °C. The design capacity of the furnace was 90 t/h and the installed power of the furnace was 72.3 MW. Based on data gained from the rolling mill of a steel mill located in Poland, analysis of the profitability of using pyrolysis gas for co-combustion with coke oven gas and natural gas in an industrial heating furnace was carried out. As a result, a significant benefit can be achieved, namely reduced production costs of the analyzed steel company by utilizing pyrolysis gas, leading to an increase in the attractiveness of the plant's products. Plastic waste and biomass are employed as energy sources in the suggested technology, therefore using them as feedstock for the pyrolysis reactor combined with the pusher type metallurgical reheating furnace is a potential proposal for the future.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133782"},"PeriodicalIF":9.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.energy.2024.133819
Edwin Alejandro Ramírez-Aguilar , David J. Sailor , Elizabeth A. Wentz
Understanding determinants of residential electricity consumption is crucial for urban sustainability efforts for planners and policy makers to develop targeted strategies to lower energy use, reduce greenhouse gas emissions, and to increase community resilience. This study presents a systematic approach to build an interpretable multivariate linear model, addressing challenges like outlier detection, multicollinearity, non-normality, and heteroscedasticity. Using 2019 summer residential electricity data for 426 census tracts in Phoenix and 30 variables, the approach involves (1) addressing multicollinearity and regression outliers through Variance Inflation Factor and studentized residual analysis, (2) comparing an automatic variable selection method with Ridge, Lasso, and Elastic Net regression, (3) evaluating the final model, and (4) interpreting variable effects. Critical findings reveal multicollinearity in land cover and racial variables, while 21 census tracts on the urban periphery exhibit outliers with unique features. Variable selection demonstrates the significance of household and building information in influencing residential electricity consumption. Household variables alone account for 84 % of electricity usage variation. Incorporating building information and land cover variables reduces errors by 35 % and 26 % respectively, emphasizing the significance of including household characteristics as predictors or control variables when modeling electricity consumption. A final model with 93 % explanatory power enables precise predictions.
{"title":"Household, sociodemographic, building and land cover factors affecting residential summer electricity consumption: A systematic statistical study in Phoenix, AZ","authors":"Edwin Alejandro Ramírez-Aguilar , David J. Sailor , Elizabeth A. Wentz","doi":"10.1016/j.energy.2024.133819","DOIUrl":"10.1016/j.energy.2024.133819","url":null,"abstract":"<div><div>Understanding determinants of residential electricity consumption is crucial for urban sustainability efforts for planners and policy makers to develop targeted strategies to lower energy use, reduce greenhouse gas emissions, and to increase community resilience. This study presents a systematic approach to build an interpretable multivariate linear model, addressing challenges like outlier detection, multicollinearity, non-normality, and heteroscedasticity. Using 2019 summer residential electricity data for 426 census tracts in Phoenix and 30 variables, the approach involves (1) addressing multicollinearity and regression outliers through Variance Inflation Factor and studentized residual analysis, (2) comparing an automatic variable selection method with Ridge, Lasso, and Elastic Net regression, (3) evaluating the final model, and (4) interpreting variable effects. Critical findings reveal multicollinearity in land cover and racial variables, while 21 census tracts on the urban periphery exhibit outliers with unique features. Variable selection demonstrates the significance of household and building information in influencing residential electricity consumption. Household variables alone account for 84 % of electricity usage variation. Incorporating building information and land cover variables reduces errors by 35 % and 26 % respectively, emphasizing the significance of including household characteristics as predictors or control variables when modeling electricity consumption. A final model with 93 % explanatory power enables precise predictions.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133819"},"PeriodicalIF":9.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.energy.2024.133801
Quan Zhang , Bin Qin , Naijun Zhou , Jingwen Lin , Jiaxu Hao , Zhaijun Lu
Accidental leakage is one of the major safety issues in the carbon capture and storage project (CCS), which may pose a significant danger to pipelines, containers and surrounding crowd. It is necessary to study the leakage behavior of high−pressure CO2, providing data support for the risk assessment of CO2 leakage. In this paper, the accidental leakage of high−pressure CO2 is simulated by releasing CO2 from a storage tank, aiming to understand the transient characteristics and thermal stratification inside the tank of CO2 leakage process. The initial CO2 is at different initial density of 600∼1000 kg/m3 and at almost the same initial pressure of 10.8 ± 0.4 MPa. Firstly, the outlet transient characteristics and temperature evolution inside the tank are presented. Then, the variation of P−T curves and phase evolution are analyzed in detail. Finally, the leakage behavior under different initial density is described. The results show that the leakage process can be clearly divided into three stages based on the outlet pressure. The outlet pressure evolution, phase evolution and temperature distribution inside the tank are very different in these three stages. This research is of great significance for leakage risk prediction, early leakage detection and leakage hazard control.
意外泄漏是碳捕集与封存项目（CCS）的主要安全问题之一，可能对管道、容器和周围人群造成重大危害。有必要研究高压二氧化碳的泄漏行为，为二氧化碳泄漏风险评估提供数据支持。本文通过从储罐中释放 CO2 来模拟高压 CO2 的意外泄漏，旨在了解 CO2 泄漏过程的瞬态特征和罐内热分层。初始 CO2 的初始密度为 600∼1000 kg/m3，初始压力几乎相同，均为 10.8 ± 0.4 MPa。首先，介绍了罐内的出口瞬态特征和温度变化。然后，详细分析了 P-T 曲线的变化和相变。最后，描述了不同初始密度下的泄漏行为。结果表明，根据出口压力，泄漏过程可清晰地分为三个阶段。在这三个阶段中，出口压力演变、相演变和罐内温度分布都有很大不同。这项研究对于泄漏风险预测、早期泄漏检测和泄漏危害控制具有重要意义。
{"title":"Experimental study on transient characteristics and thermal stratification of high−pressure CO2 leakage under different initial density","authors":"Quan Zhang , Bin Qin , Naijun Zhou , Jingwen Lin , Jiaxu Hao , Zhaijun Lu","doi":"10.1016/j.energy.2024.133801","DOIUrl":"10.1016/j.energy.2024.133801","url":null,"abstract":"<div><div>Accidental leakage is one of the major safety issues in the carbon capture and storage project (CCS), which may pose a significant danger to pipelines, containers and surrounding crowd. It is necessary to study the leakage behavior of high−pressure CO<sub>2</sub>, providing data support for the risk assessment of CO<sub>2</sub> leakage. In this paper, the accidental leakage of high−pressure CO<sub>2</sub> is simulated by releasing CO<sub>2</sub> from a storage tank, aiming to understand the transient characteristics and thermal stratification inside the tank of CO<sub>2</sub> leakage process. The initial CO<sub>2</sub> is at different initial density of 600∼1000 kg/m<sup>3</sup> and at almost the same initial pressure of 10.8 ± 0.4 MPa. Firstly, the outlet transient characteristics and temperature evolution inside the tank are presented. Then, the variation of <em>P−T</em> curves and phase evolution are analyzed in detail. Finally, the leakage behavior under different initial density is described. The results show that the leakage process can be clearly divided into three stages based on the outlet pressure. The outlet pressure evolution, phase evolution and temperature distribution inside the tank are very different in these three stages. This research is of great significance for leakage risk prediction, early leakage detection and leakage hazard control.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133801"},"PeriodicalIF":9.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three-heat-reservoir (THR) heat transformers can upgrade temperature gradient of thermal energy, and lots of instructive research has been conducted in the last decades. However, study of THR heat transformer cycle theory in micro systems remains lacking. By employing macro equivalent combined cycle method, this paper builds a finite-time thermodynamic model of THR thermal Brownian heat transformer, which is a combination of a two-reservoir thermal Brownian heat pump driven by a two-reservoir thermal Brownian engine. Expressions of performance parameters are deduced, and operating temperatures and external load ratio are determined by solving heat balance equations. Maximal heating load and corresponding coefficient of performance (COP) are given by modulating external load, heat exchanger inventory allocations and barrier height synchronously, and the optimal thermal conductance allocations and optimal working temperatures are identified. Results indicate that external thermal resistances affect heat flow transmission and the coupling of combined cycle, ultimately shaping the cycle performance. Half of the overall heat exchanger inventory should be arranged in middle heat exchanger under maximal heating load objective. Heating load exhibits an extremum with respect to COP. Equivalent combined cycle modelling is an effective and efficient method for performance optimization of THR thermal Brownian heat transformers with external heat-transfer.
{"title":"Equivalent combined cycle modeling and performance optimization for a three-heat-reservoir thermal Brownian heat transformer with external heat-transfer","authors":"Congzheng Qi , Lingen Chen , Yanlin Ge , Huijun Feng","doi":"10.1016/j.energy.2024.133792","DOIUrl":"10.1016/j.energy.2024.133792","url":null,"abstract":"<div><div>Three-heat-reservoir (THR) heat transformers can upgrade temperature gradient of thermal energy, and lots of instructive research has been conducted in the last decades. However, study of THR heat transformer cycle theory in micro systems remains lacking. By employing macro equivalent combined cycle method, this paper builds a finite-time thermodynamic model of THR thermal Brownian heat transformer, which is a combination of a two-reservoir thermal Brownian heat pump driven by a two-reservoir thermal Brownian engine. Expressions of performance parameters are deduced, and operating temperatures and external load ratio are determined by solving heat balance equations. Maximal heating load and corresponding coefficient of performance (COP) are given by modulating external load, heat exchanger inventory allocations and barrier height synchronously, and the optimal thermal conductance allocations and optimal working temperatures are identified. Results indicate that external thermal resistances affect heat flow transmission and the coupling of combined cycle, ultimately shaping the cycle performance. Half of the overall heat exchanger inventory should be arranged in middle heat exchanger under maximal heating load objective. Heating load exhibits an extremum with respect to COP. Equivalent combined cycle modelling is an effective and efficient method for performance optimization of THR thermal Brownian heat transformers with external heat-transfer.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133792"},"PeriodicalIF":9.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-12DOI: 10.1016/j.energy.2024.133807
Fanyi Meng , Zhenmin Luo , Yingying Yu , Tao Wang , Bin Su , Chunmiao Yuan , Gang Li , Xiaochen Hou
Due to low melting and boiling points and extreme reactivity in the chemical reaction of Mg powder, inert powders that have a significant inerting effect on Mg dust clouds can cause significant combustion enhancement of the accumulated Mg dust layer. To circumvent this unforeseen fire hazard, this research selects five types of inertants that have been demonstrated to exert an inerting effect on metal dust clouds and possess a potential flame-retardant effect on Mg dust layers. This research aims to investigate the effect of inert powders on Mg dust layers to identify an efficient inerting mechanism for Mg dust layers. The results indicate that the selection of inertants for Mg dust must be based on a comprehensive evaluation of their physical and chemical properties. The presence of substances with strong decomposition and decomposition products that readily produce gases will destroy the oxide crust on the surface of the accumulated Mg dust layer, thereby causing violent gas-phase combustion. In the case of highly chemically stable substances, the melting point is of primary importance. The formation of cracks in the oxide crust is also a consequence of the higher melting point of inertants, resulting in a combustion enhancement of the mixed dust layer. Inertants with a low melting point and a high boiling point demonstrate a high degree of inerting efficiency for Mg dust layers. The melting of the inert substances forms a liquid film, which prevents the Mg powder from coming into contact with the air surrounding and within the combustion zone. The results of this research are both instructive and valuable for preventing explosions in the process industry involving metal dust materials.
{"title":"Multiple effects of high efficiency solid inertants on fire hazard of the accumulated Mg dust layer","authors":"Fanyi Meng , Zhenmin Luo , Yingying Yu , Tao Wang , Bin Su , Chunmiao Yuan , Gang Li , Xiaochen Hou","doi":"10.1016/j.energy.2024.133807","DOIUrl":"10.1016/j.energy.2024.133807","url":null,"abstract":"<div><div>Due to low melting and boiling points and extreme reactivity in the chemical reaction of Mg powder, inert powders that have a significant inerting effect on Mg dust clouds can cause significant combustion enhancement of the accumulated Mg dust layer. To circumvent this unforeseen fire hazard, this research selects five types of inertants that have been demonstrated to exert an inerting effect on metal dust clouds and possess a potential flame-retardant effect on Mg dust layers. This research aims to investigate the effect of inert powders on Mg dust layers to identify an efficient inerting mechanism for Mg dust layers. The results indicate that the selection of inertants for Mg dust must be based on a comprehensive evaluation of their physical and chemical properties. The presence of substances with strong decomposition and decomposition products that readily produce gases will destroy the oxide crust on the surface of the accumulated Mg dust layer, thereby causing violent gas-phase combustion. In the case of highly chemically stable substances, the melting point is of primary importance. The formation of cracks in the oxide crust is also a consequence of the higher melting point of inertants, resulting in a combustion enhancement of the mixed dust layer. Inertants with a low melting point and a high boiling point demonstrate a high degree of inerting efficiency for Mg dust layers. The melting of the inert substances forms a liquid film, which prevents the Mg powder from coming into contact with the air surrounding and within the combustion zone. The results of this research are both instructive and valuable for preventing explosions in the process industry involving metal dust materials.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133807"},"PeriodicalIF":9.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For clean energy systems such as wind, solar and nuclear plants, the output power is usually regulated by controlling the motion rate of actuators, e.g. the stepping motors utilized for sun tracking of solar photovoltaic panels, yaw and pitch angle positioning of wind turbines and control rod driving of nuclear reactors. By constraining the actuators' motion rates to a finite set of values, the control system of a clean energy plant can be much simplified with obvious enhancement in operation reliability but requires developing finite-set control methods correspondingly. Motivated by the benefit of adopting finite motion rates, a finite-set control method is newly proposed for the nonlinear systems describing the dynamics of clean energy plants, compensating for the quantization and saturation effects induced by adopting a finite set of motion rates while ensuring globally bounded closed-loop stability strictly under a sufficient condition. The method is applied to design a finite-set power-level control of modular high temperature reactors, demonstrating stable power-level control during a reactor ramping-down from 100 % to 50 % reactor full power (RFP) with a constant rate of 5 % RFP/min. The simulation results also indicate that under the regulation of the finite-set control law, the steady error of hot helium temperature can eliminated, and the overshoot of neutron flux and that of hot helium temperature can be reduced by approximately 66 % and 75 % through properly adjusting control parameters, providing practical insights for engineering applications.
{"title":"Nonlinear finite-set control of clean energy systems with nuclear power application","authors":"Zhe Dong, Junyi Li, Jiasen Zhang, Xiaojin Huang, Yujie Dong, Zuoyi Zhang","doi":"10.1016/j.energy.2024.133773","DOIUrl":"10.1016/j.energy.2024.133773","url":null,"abstract":"<div><div>For clean energy systems such as wind, solar and nuclear plants, the output power is usually regulated by controlling the motion rate of actuators, e.g. the stepping motors utilized for sun tracking of solar photovoltaic panels, yaw and pitch angle positioning of wind turbines and control rod driving of nuclear reactors. By constraining the actuators' motion rates to a finite set of values, the control system of a clean energy plant can be much simplified with obvious enhancement in operation reliability but requires developing finite-set control methods correspondingly. Motivated by the benefit of adopting finite motion rates, a finite-set control method is newly proposed for the nonlinear systems describing the dynamics of clean energy plants, compensating for the quantization and saturation effects induced by adopting a finite set of motion rates while ensuring globally bounded closed-loop stability strictly under a sufficient condition. The method is applied to design a finite-set power-level control of modular high temperature reactors, demonstrating stable power-level control during a reactor ramping-down from 100 % to 50 % reactor full power (RFP) with a constant rate of 5 % RFP/min. The simulation results also indicate that under the regulation of the finite-set control law, the steady error of hot helium temperature can eliminated, and the overshoot of neutron flux and that of hot helium temperature can be reduced by approximately 66 % and 75 % through properly adjusting control parameters, providing practical insights for engineering applications.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"313 ","pages":"Article 133773"},"PeriodicalIF":9.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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