Numerical Simulation of Heat Transfer Process and Heat Loss Analysis in Siemens CVD Reduction Furnaces

The modified Siemens method is the dominant process for the production of polysilicon,yet it is characterised by high energy consumption.Two models of laboratory-grade Siemens reduction furnace and 12 pairs of rods industrial-grade Siemens chemical vapor deposition(CVD)reduction furnace were established,and the effects of factors such as the diameter of silicon rods,the surface temperature of silicon rods,the air inlet velocity and temperature on the heat transfer process inside the reduction furnace were investigated by numerical simulation.The results show that the convective and radiant heat losses in the furnace increased with the diameter of the silicon rods.Furthermore,the radiant heat loss of the inner and outer rings of silicon rods was inconsistent for the industrial-grade reduction furnace.As the surface temperature of the silicon rods increases,the convective heat loss in the furnace increases,while the radiative heat loss remains relatively constant.When the inlet temperature and inlet velocity increase,the convective heat loss decreases,while the radiant heat loss remains relatively constant.Furthermore,the furnace wall surface emissivity increases,resulting in a significant increase in the amount of radiant heat loss in the furnace.In practice,this can be mitigated by polishing or adding coatings to reduce the furnace wall surface emissivity.

Reducing Electrical Consumption in Stationary Long-Haul Trucks

On average, long-haul trucks in the U.S. use approximately 667 million gallons of fuel each year just for idling. This idling primarily facilitates climate control operations during driver rest periods. To mitigate this, our study explored ways to diminish the electrical consumption of climate control systems in class 8 trucks through innovative load reduction technologies. We utilized the CoolCalc software, developed by the National Renewable Energy Laboratory (NREL), which integrates heat transfer principles with extensive weather data from across the U.S. to mimic the environmental conditions trucks face year-round. The analysis of the CoolCalc simulations was performed using MATLAB. We assessed the impact of various technologies, including white paint, advanced curtains, and Thinsulate insulation on reducing electrical demand compared to standard conditions. Our findings indicate that trucks operating in the eastern U.S. could see electrical load reductions of up to 40%, while those in the western regions could achieve reductions as high as 55%. Such significant decreases in energy consumption mean that a 10 kWh battery system could sufficiently manage the HVAC needs of these trucks throughout the year without idling. Given that many long-haul trucks are equipped with battery systems of around 800 Ah (9.6 kWh), implementing these advanced technologies could substantially curtail the necessity for idling to power air conditioning systems.

Comparative evaluation of energy and resource consumption for vacuum carbothermal reduction and Pidgeon process used in magnesium production

With the fast development of the application of magnesium based alloys,the demand for primary magnesium is increasing dramatically all over the world.The Pidgeon process is the most widely used process for producing magnesium in China,but suffers from problems such as high energy,resource consumption and environmental pollution.While the process of vacuum carbothermal reduction to produce magnesium(VCTRM)has attracted more and more attention as its advantages,but it has not been well-practiced in industrial applications and there also is no comprehensive and quantitative analysis of this process.This study quantified the flows of resource and energy for the Pidgeon process and the VCTRM process,then compared and analyzed these two processes with each other from three aspects.The VCTRM process results in 63.14%and 69.16%lower of non-renewable mineral resources and energy consumptions when compared to the Pidgeon process,respectively.Moreover,the low energy consumption(2.675 tce vs.8.681 tce)and material to magnesium ratio(2.953:1 vs.6.429:1)of the VCTRM process,which lead to lower greenhouse gas(GHG)emissions(8.777 t vs.26.337 t)and solid waste generation(0.522 t vs.5.465 t)with a decrease of 66.67%and 90.45%,respectively.Results indicate that the VCTRM process is a more environmentally friendly process for magnesium production with high efficiency but low cost and low pollution,and it shows a good potential to be industrialized in the future after solving the bottleneck problem of the reverse reaction.

Analysis of Changes in Insecticide Consumption at Home and Abroad in Recent 30 Years

The paper analyzes the changes in insecticide consumption and the proportion of insecticides in pesticides in the world and several typical countries in the past 30 years,in order to provide a reference for scientific treatment of pesticide and further implementation of China s"double reduction"policy.

Minimization of Air Consumption and Potential Savings of Textile Denim Fabric Manufacturing Process

One of the most important aspects of Bangladesh’s textile industry is denim. Bangladesh now has a new opportunity thanks to the global demand for denim among fashion industry professionals. Entrepreneurs from Bangladesh provide denim products to well-known international merchants all over the world. The worldwide denim market is predicted to expand by roughly 8% through the year 2020. We must raise the standard of denim if we are to keep up with the expanding industry. In contrast to projectile and rapier systems, air-jet weaving machines nowadays can weave practically all types of yarns without any issues and at higher rates. Due to this, air-jet looms are an excellent substitute for other weft insertion techniques. This kind of device still has one significant flaw, though, and that is the enormous power consumption brought on by the creation of compressed air. Researchers and manufacturers of air-jet looms have therefore worked very hard to find a solution to this issue and achieve a huge reduction in air consumption without compromising loom performance or fabric quality. Therefore, the purpose of this project is to look into ways to decrease air consumption and reduce auxiliary selvedge waste without any decrease in loom performance and fabric quality on existing air-jet weaving looms which reduce the manufacturing costs with process improvement. Just updating the air pressure allowed a weaving mill to reduce air usage by 11 cfm. So, with just almost no cost, a company with 100 looms could save $0.15 M each year, on compressed air. Two new methods for decreasing process costs on air jet looms have also been developed by this project work.

Energy Consumption Analysis and Optimization of Electric Submersible Pump System

Electric submersible pumps account for a considerable proportion in the development of the Bohai Oilfield. Improving the system efficiency of the electric submersible pump wells, ensuring that the units operate in the high-efficiency zone, is essential. Analysis shows that the efficiency of the electric submersible pump system depends on the wear and tear of each component of the submersible pump equipment, the setting of operational parameters, and more importantly, the production status and daily management level of the oil well. Therefore, improving the structural performance of the submersible pump product, optimizing the parameters setting of the oil well, strengthening daily management, establishing a scientific management system, and improving the production management process and system can effectively improve the production efficiency and economic benefits of the oil well, and further achieve the goal of energy saving and emission reduction. In addition, it is necessary to actively promote the concept and technology of energy saving and emission reduction, encourage oilfield enterprises to explore effective measures to reduce the energy consumption of the electric submersible pump system by strengthening the scientific management system, and achieve a green, low-carbon, and high-quality development of oilfield production to achieve the unity of economic benefits, social benefits, and environmental benefits. This article applies the above measures in the P oilfield to achieve energy optimization of submersible electric pump systems, reducing the daily power consumption of single well submersible electric pump systems by 371 kWh per day, increasing the submersible electric pump's lifespan by 200 days, generating considerable project benefits.

Aerodynamic drag reduction of heavy vehicles using append devices by CFD analysis

Improving vehicle fuel consumption,performance and aerodynamic efficiency by drag reduction especially in heavy vehicles is one of the indispensable issues of automotive industry.In this work,the effects of adding append devices like deflector and cab vane corner on heavy commercial vehicle drag reduction were investigated.For this purpose,the vehicle body structure was modeled with various supplementary parts at the first stage.Then,computational fluid dynamic(CFD) analysis was utilized for each case to enhance the optimal aerodynamic structure at different longitudinal speeds for heavy commercial vehicles.The results show that the most effective supplementary part is deflector,and by adding this part,the drag coefficient is decreased considerably at an optimum angle.By adding two cab vane corners at both frontal edges of cab,a significant drag reduction is noticed.Back vanes and base flaps are simple plates which can be added at the top and side end of container and at the bottom with specific angle respectively to direct the flow and prevent the turbulence.Through the analysis of airflow and pressure distribution,the results reveal that the cab vane reduces fuel consumption and drag coefficient by up to 20 % receptively using proper deflector angle.Finally,by adding all supplementary parts at their optimized positions,41% drag reduction is obtained compared to the simple model.

Fuel Consumption Potential of the Pushbelt CVT

The efforts to further reduce fuel consumption of vehicles equipped with a pushbelt type Continuously Variable Transmission(CVT) focus on different sources of loss.In this paper the magnitude of these losses and their potential for reduction is described.Inside the CVT,the variator,its control strategy and the hydraulic actuation circuit can be distinguished as the main potentials.A major opportunity is offered by a new control strategy that takes the actual slip between belt and pulley as the control parameter.The resulting decrease of clamping forces on the pushbelt leads to a reduction of variator and actuation losses.Further potential is found in the hydraulic actuation circuit by an improved tuning of the power supply to the actual power requirement.Outside the CVT additional potential is found in start-stop functionality as supported by measures inside the transmission.The paper describes the theoretical background as well as practical fuel savings of up to 5.5% that were obtained in tests on vehicle level.Slip control adds an inherent robustness to the operation of the pushbelt and opens up the fuel saving potential of the CVT thus reinforcing its position as the benchmark for the near future.

Analysis of users’ electricity consumption behavior based on ensemble clustering

Due to the increase in the number of smart meter devices,a power grid generates a large amount of data.Analyzing the data can help in understanding the users’electricity consumption behavior and demands;thus,enabling better service to be provided to them.Performing power load profile clustering is the basis for mining the users’electricity consumption behavior.By examining the complexity,randomness,and uncertainty of the users’electricity consumption behavior,this paper proposes an ensemble clustering method to analyze this behavior.First,principle component analysis(PCA)is used to reduce the dimensions of the data.Subsequently,the single clustering method is used,and the majority is selected for integrated clustering.As a result,the users’electricity consumption behavior is classified into different modes,and their characteristics are analyzed in detail.This paper examines the electricity power data of 19 real users in China for simulation purposes.This manuscript provides a thorough analysis along with suggestions for the users’weekly electricity consumption behavior.The results verify the effectiveness of the proposed method.

Effects of Ambient Temperature and Shaft Power Variations on Creep Life Consumption of Industrial Gas Turbine Blades

The effects of ambient temperature and shaft power variations on creep life consumption of compressor turbine blades of LM2500+ industrial gas turbine engine are investigated in this work. An engine model was created in PYTHIA (Cranfield University’s gas turbine software) for the analysis. Blade thermal and stress models were developed and used together with Larson-Miller Parameter method for life analysis. Mean life reduction index, which is the propensity of a given effect to reduce engine life by half, is developed for each effect and applied in this research to compare the impacts of the different effects on the blade creep life. It was observed that blade life will be halved when ambient temperature is increased by 8.11 units while 13.64% increase in shaft power reduces blade life by a factor of 2. The results of this work will guide engine operators in making decisions concerning operating at part loads.

Smoking reduction did not promote future smoking cessation in a general population

Introduction: Smoking reduction (SR) has been introduced as a strategy for smokers who are unwilling or unable to quit. We wanted to investi tigate whether SR at one-year follow-up increased the probability of abstinence from smoking at three and five-year follow-up. Methods: we included a random sample from a general population, the Inter99 study, Copenhagen, Denmark. A total of 1975 participants were daily smokers (from both the intervention and the control group) with information on tobacco consumption at both baseline and one-year follow-up (year 1999 to 2001). Of these, 112 had reduced their tobacco consumption substantially, by minimum 50%, at one-year follow-up. Information on tobacco consumption and smoking status was available on 1441 and 1308 participants at three-year and five-year follow-up, respectively. Outcome was self-reported point abstinence at three and five-year follow-up. Logistic regression analyses were adjusted for confounders. Results: One out of five smokers (20.5%) had maintained their reduced tobacco consumption at five-year follow-up. About twice as many reducers as non-reducers reported that they had tried to quit since baseline (p < 0.05). In adjusted logistic regression analyses we found no association between SR at one-year follow- up and being point abstinent at three-year (OR: 0.57;CI: 0.28 - 1.15) or five-year follow-up (OR: 1.08;CI: 0.56 - 2.09). Conclusions: Our study, including smokers from a general population found no association between substantial SR and future smoking cessation at three- and five-year follow-up. No studies so far have reported that SR undermines smoking cessation, but it is still controversial whether SR significantly increases future smoking cessation.

中国水泥行业2011-2022年二氧化碳和大气污染物排放分析

2011—2021年,熟料产量呈波动上升趋势。水泥行业整体生产运行水平不断提高,熟料单条生产线平均规模由43.8万t/条提升至115.3万t/条,熟料单位产品综合能耗下降14.4%,熟料单位产品CO_(2)排放强度下降6.3%,但CO_(2)排放总量增加了13.8%,与氮氧化物减排趋势形成较大反差,碳污治理水平差距明显。熟料生产中石灰石分解和煤炭燃烧过程的CO_(2)排放合计占比为92.9%~93.8%,是CO_(2)排放的主要来源。由于熟料系数偏高、非碳酸盐原料替代不足、综合能耗仍然较高等原因,安徽等7个熟料产量大的省份的CO_(2)排放强度高于全国。建议实行碳酸盐熟料产量总量控制,逐步降低熟料应用比例,加快建材市场熟料产品和非碳酸盐原料替代,降低高标号水泥使用比例。应大力推广水泥行业节能降耗增效技术,加快熟料落后产能淘汰。对熟料产量大、碳排放强度高的地区,应结合当地碳排放特点,实行差别化降碳策略。各大气污染防治重点区域应因地施策推进水泥行业减污降碳工作。

保供降碳目标下能源转型模式及转型时点分析

应对气候变化目标要求全球能源系统进行广泛而深刻的转型。由于资源禀赋、能源战略、技术水平等差异,各国能源转型进程呈现出明显的异质性特征。通过对主要国家能源转型特征与减煤路径的分析,归纳了4种典型模式:能效提高模式、增气减煤模式、煤炭洁净利用模式、新能源替代模式,不同模式在不同时间点上与经济社会发展交互影响形成了国际能源转型的内在驱动机制。采用面板数据模型识别了影响能源转型模式的重要因素,并利用历史趋势分析方法对我国化石能源消费“拐点”与减煤时间节点进行研究。研究表明,当人均GDP达到25500美元时,发达国家即出现化石能源减少拐点。国家创新指数和城镇化与煤炭消费占比呈负相关,第二产业增加值占比与煤炭消费占比呈正相关。我国预计减煤时间范围在2028-2035年,化石能源消费减少时点在2040年左右。考虑到我国以煤炭为主的能源资源禀赋,我国能源转型目标的实现须依赖于煤炭洁净利用为主的转型路径,大力发展低碳化现代煤基能源体系,改变传统煤炭利用理念与方式,为未来多能耦合的新型能源体系提供重要支撑。

数字普惠金融对能源环境效率的影响机制与空间效应

在“双碳”约束日益紧迫和经济下行压力加大的现实背景下,数字普惠金融成为城市经济绿色低碳高质量发展的新动能和可持续增长极。使用非径向方向距离函数测算中国2011-2020年273个地级市能源环境效率,实证检验数字普惠金融对能源环境效率的空间效应及其影响机制。研究发现:(1)能源环境效率呈现出正向空间依赖特征,本地区能源环境效率的提高可以对空间关联地区的能源环境效率产生积极影响。(2)数字普惠金融提高了本地区的能源环境效率,且对周边地区的能源环境效率具有显著正向的空间溢出效应。(3)数字普惠金融主要通过推动节能降耗、促进绿色技术创新和优化产业结构三条途径提高能源环境效率,并且数字普惠金融能通过这三条途径同时提高本地区和周边地区的能源环境效率。(4)数字普惠金融对能源环境效率的正向空间溢出效应在使用深度和数字化程度维度、500km范围内、大型城市、非老工业基地和东部城市更加明显。研究结论为中国能源绿色低碳转型的金融服务优化路径提供了科学决策依据。

中国煤炭价格与碳排放权交易价格的传导路径研究

碳市场作为新兴市场易受能源价格因素干扰,在“双碳”目标下研究煤炭价格与碳排放权交易价格(以下简称为碳价)的传导路径,有利于碳市场的健康运行并助力其发挥减排作用。在梳理煤炭价格与碳价传导机理的基础上,利用DCC-GARCH模型揭示煤炭指数与碳价的动态关系,并运用VAR模型实证检验煤炭价格与碳价的传导路径及能源消费结构、能源效率与动态相关系数的因果关系。实证结果表明:煤炭价格与碳价存在显著动态相关性,并呈现复杂性和多变性;碳市场尚未充分发挥其创新激励效应,相较于能源利用效率,煤炭价格与碳价通过能源消费结构路径实现的传导更加显著;能源消费结构调整是动态相关系数变化的格兰杰原因,而能源利用效率改变则不是。

沈阳地区典型办公建筑运行阶段碳减排潜力研究

以沈阳某办公建筑为例,将GB 50189—2015《公共建筑节能设计标准》作为节能基准,对比分析多种近零能耗建筑技术情形对建筑碳排放的影响,并对其碳减排潜力进行评估测算。利用模拟软件Design Builder对沈阳市某办公建筑建立典型模型,通过模拟计算得到几种不同技术情形下的能耗强度。碳排放强度由不同类型能源碳排放因子与能耗强度计算得出。结果表明:可再生能源利用技术和暖通空调设备能效提升技术可明显减少碳排放,碳减排率分别可达到44.88%和39.99%;另外,建筑围护结构改造以及自然通风和自然采光结合技术,减排率分别为8.18%、7.22%。按照近零能耗建筑技术要求,综合6种技术情形,办公建筑运行阶段的减排率可达51.08%。

重整生成油管式反应器液相加氢工艺(FITS)的工业应用

针对某石化公司1.0 Mt/a连续催化重整装置苯产品白土预处理工艺精制深度不够、重组分产量大、白土失活快以及二甲苯加氢系统工艺流程较复杂、能耗大等问题,采用中国石化长岭分公司和湖南长岭石化科技开发有限公司共同开发的重整生成油管式反应器液相加氢工艺(简称FITS工艺)对重整生成油进行脱烯烃处理。该工艺利用氢气纳米级微孔分散技术,使氢气在油相中均匀分散,能有效脱除重整生成油中的烯烃,满足苯产品溴指数小于20 mgBr/(100 g)、混合二甲苯产品溴指数小于50 mgBr/(100 g)的控制要求。FITS工艺的成功投用,可以停用精制苯的白土罐、二甲苯的加氢单元,大幅降低了芳烃处理单元的能耗和运行成本。

数字金融是否降低了家庭消费碳排放?

依托互联网、大数据、云计算等数字技术,中国数字金融获得了快速发展,深刻影响了居民的生活方式和消费习惯,其在消费端的碳减排效果有待科学评估。基于2015年、2017年和2019年中国家庭金融调查数据以及北京大学发布的数字普惠金融指数,实证检验了数字金融对家庭消费碳排放的影响及作用机制。研究发现,数字金融降低了家庭消费碳排放,且主要通过促进消费结构升级降低了家庭消费碳排放。异质性分析显示,在西部地区家庭、户主处于失业状态家庭、高消费家庭中以及地区数字金融发展水平较低时,数字金融降低家庭消费碳排放的效果更加显著。针对数字金融三个维度的进一步分析表明,相较于数字化程度,数字金融在覆盖广度、使用深度方面的表现才是降低家庭消费碳排放的关键。因此,应大力推进数字金融的发展,并积极推动居民消费结构升级,有效地降低家庭消费碳排放,进而助力实现“双碳”目标。

“双碳”目标下山东省能源现状及减碳对策

为加快山东省新旧动能转换,山东省亟需发展高比例新能源,建设新型能源体系。基于山东省统计年鉴数据,借助IPCC测算法、Tapio脱钩理论,统计分析了山东省2017—2022年能源消费现状、碳排放总量及特征,针对能源碳排放量持续上升和能源消费比例不合理提出对应的减碳对策。结果发现,2017—2022年山东省碳排放总量逐年上升,山东省煤炭消费占比约为世界平均水平的2倍,高于全国平均水平,清洁能源消费占比偏低。尽管全省碳排放强度因能源强度下降而持续优化,但是碳脱钩系数一直是弱脱钩的状态,碳脱钩系数距离强脱钩尚有一定距离。从调整能源结构、优化产业结构等角度,提出了大力发展绿色低碳能源、积极推进光伏发电项目、加快非常规天然气的开发、推动清洁能源产业与可再生能源的发展的相应对策。进一步促进高比例新能源发展、新型能源体系建设是提高山东省能源利用效率、推动经济发展的正确手段。

基于节能降耗的飞轮储能电力计量技术

飞轮储能电力计量技术,是一种将飞轮储能与电力计量技术相结合的创新型电力管理技术。飞轮储能以其高功率密度、长寿命、快速响应和环保无污染等特点,在电力系统中展现出巨大的应用潜力。而电力计量技术则是电力系统中的重要组成部分,用于准确计量和监测电能的使用情况。将两者结合,飞轮储能电力计量技术旨在提高电力系统的运行效率,优化资源配置,并推动电力行业的可持续发展。本文从节能降耗的角度出发,分析飞轮储能电力计量技术的应用研究情况,并从多个角度阐述未来飞轮储能电力计量技术的应用研究方向,以实现对电力系统的高效、绿色管理。