碳中和愿景下电力部门低碳转型路径研究

碳中和愿景一方面加速了全社会电气化发展,致使电力需求持续增加,另一方面对尽早实现零碳电力提出要求,电力部门低碳转型进程更加紧迫而复杂。本文首先定性分析碳中和背景下电力部门的总体转型思路和技术不确定性影响,其次采用电力部门与终端部门耦合的C~3IAM/NET模型对电力需求进行预测,同时根据关键低碳技术发展的保守预期和积极预期设计多种情景,以开展电力低碳转型路径优化和成本效益研究。结果显示,发电碳排放量峰值可能出现在40亿～42亿吨,在2049—2060年有望实现零碳电力,电力部门低碳转型速度和效果因技术不确定性而存在明显差异。2021—2060年电力低碳转型累计投入为171万亿～180万亿元,CCS技术累计减排贡献超过250亿吨,可再生能源电力占比需达到68%以上,风电和光电将成为主要电力。     

池火灾热辐射下的最小安全距离

防火间距是石油化工企业平面设计中的一个重要参数 ,笔者旨在从流体力学角度研究池火灾发生情况下邻罐之间最小安全距离 ,从而给防火间距的制定提供依据。辐射是储罐区池火灾的主要传热方式 ,作者对池火灾形状以及介质辐射吸收性质进行了适当的简化 ,用CFD软件Fluent对丙烷液化烃储罐池火灾热辐射进行了数值模拟。模拟结果表明对于锰钢材料、内径为 1 2 4 1 0mm液化烃压力储罐 ,稳态池火灾情况下 ,相邻两储罐之间的最小安全距离为 1 5m。     

小城镇环境保护规划存在的问题与对策

根据全国生态环境保护“十五”计划要求,在计划期间力争60％的小城镇完成环境保护规划,广西小城镇由于经济发展不平衡,部分小城镇还比较落后,且存在较多的环境问题,目前小城镇的环境保护规划尚未得到有效的开展,因此应及时找出问题和差距,并根据存在的问题作出相应的对策,在计划期内是可以完成小城镇环境保护规划的目标,为广西小城镇的可待续发展提供环境保障。     

Air Pollution Effects on Forest Trees in Balikesir,Turkey

Air pollution has become an actual problem in Balikesir because of rapid urbanisation and increasing of the polluting sources. Air pollutionproblems occur under the unfavorable meteorological conditions which increase in frequency of occurrence in winter due to use of low quality lignite coals for heating. The `Protection of Air Quality' in Turkey dated 1986 is based on the human health criteria. But the critical limit values are lethal for the forest trees as far as SO₂ is concerned. The field observations showed that leaves of the trees have yellow spots indicating acid burns in Balikesir. This study aims at determining the relationships between the SO₂ concentrationsin the air under selected climatic conditions, and the effects of air pollution on forest trees in Balikesir. Samples of leaves were collected from the City Parks in Balikesir, Deirmenboaz forested area located 10 km far fromBalikesiron the Balikesir-Bursa highway, and from the forestation areas near the Balikesir-Edremit highway. Sulfur contents of the leaves were very high especially in the city (2650–5300 g m^-3).Samples from other areas had values lower than this range but above the usual values (850–3612 g m^-3). The diameter increments of the trees were found to be lower and these results clearly showed the adverse impacts. Negative correlations were found between these sulfur concentrations and the daily mean temperatures and wind speeds. Positive correlation was seen between these concentrations and pressures, humidities. Emission sources must be controlled in order to safeguard the forests which protects the soil, facilitate water production, assimilate carbon dioxide in air and produce oxygen. It must be considered that the problems are not only regional but have a global identity.     

Wildfire effects on hiking and biking demand in New Mexico: a travel cost study

We use a travel cost model to test the effects of wild and prescribed fire on visitation by hikers and mountain bikers in New Mexico. Our results indicate that net benefits for mountain bikers is $150 per trip and that they take an average of 6.2 trips per year. Hikers take 2.8 trips per year with individual net benefits per trip of $130. Both hikers' and mountain bikers' demand functions react adversely to prescribed burning. Net benefits for both groups fall as areas recover from prescribed burns. Because both visitation and annual recreation benefits decrease to these two types of visitors, this gives rise to multiple use costs associated with prescribed burning. With respect to wildfire, hikers and mountain bikers both exhibit decreased visitation as areas recover from wildfires, however, only hikers indicate an increase in per trip net benefits. Bikers' demand effectively drops to zero. These results differ from previous findings in the literature and have implications for efficient implementation of the National Fire Plan and whether prescribed burning is a cost effective tool for multiple use management of National Forests. Specifically, that fire and recreation managers cannot expect recreation users to react similarly to fire across recreation activities, or different geographic regions. What is cost effective in one region may not be so in another.     

大兴安岭林区地下火形成火环境研究

地下火作为森林中一种难以控制的燃烧现象,其形成机理极为复杂。我国大兴安岭林区是森林地下火的多发地区。对该地区2002年发生的地下火研究表明：丰富的近土壤层和地下可燃物是森林地下火发生的物质条件,气象条件促进了森林地下火的发生,特别是在遇到降水少、长期干旱、地面温度增加、相对湿度降低和可燃物干燥的情况下,就很容易引起地下火灾。地下火有地理和时间分布特征。地表火主要发生在原始森林区域,如针叶林、阔叶林或针阔混交林,都有可能发生地下火。地下火一般燃烧速度慢,持续时间长,燃烧充分,具有隐蔽性强、燃烧不连续、方向易变等特点,地下火在所有火灾中对森林危害最大,特别是对落叶松、樟子松、云杉等的破坏更为严重。     

火灾中双层窗玻璃破裂机理的研究

把单层窗玻璃破裂的模型作为研究基础,基于原有的单层窗玻璃破裂的计算软件开发设计了双层窗玻璃破裂的模型,并对双层玻璃的内表面及其空隙的热传递过程和连续发生的玻璃破裂机理进行了研究。     

回燃及其对腔室火灾过程的影响

从火灾中的两种特殊火行为－轰燃和回燃的发生机理出发,着重讨论了回燃在整个火灾过程中的作用以及回燃对轰燃的影响。结果表明,由于回燃和轰燃同为火灾全过程中的分过程,并且由于二者发生机理的相似性,因而,它们可以建立联系。当具备合适的热解产物浓度时,回燃过程可以使火灾系统的状态突变到完全发展状态,即引发轰燃。     

轴心受压钢筋混凝土柱等效火灾荷载的计算

迄今为止，国内外有关计算构件耐火极限的方法，是钢筋混凝土构件与防火研究的主要内容。而在结构设计中，由于直接考虑的是荷载作用，为此提出了一个新概念——等效火灾荷载，将火灾对结构的影响直接考虑成荷载作用。在确定了混凝土柱的截面温度场后，利用一种简化计算方法计算出钢筋混凝土柱的等效火灾荷载，进而计算出钢筋混凝土柱的耐火极限。在火灾中，作为结构最基本的构件柱可能受到单面或多面的火作用，这里仅介绍轴心受压钢筋混凝土柱等效火灾荷载的计算。     

火灾模拟结果误差分析的函数分析法

火灾试验结果和模拟预测结果常能表达成关于时间变化的曲线,为定量描述两种随时间变化曲线间相符合的程度,引入误差分析的函数分析法。采用适合于低Mach数流修正的N-S方程描述烟气的输运过程,使用大涡模拟和Smagorinsky亚格子模型,对封闭空间内的火灾过程进行数值模拟;对其计算结果的分析表明,函数分析法能定量对模拟预测曲线与试验曲线间的差别进行描述,模是两曲线值大小的相对误差的度量,余弦是两曲线形状相似程度的度量。