共查询到20条相似文献，搜索用时 560 毫秒
1.
2.
一、燃气锅炉节能技术
（一）冷凝技术
锅炉燃料完全燃烧后其烟气被冷却至原始温度,其中的水蒸气以凝结水状态排出时所放出的热量称为高位发热量,而水蒸气仍为蒸汽状态时所放出的热量称为低位发热量。燃料的高位发热量在数值上大于其低位发热量,差值为水蒸气的汽化潜热, 相似文献
3.
谢光凤 《数理天地(初中版)》2005,(5)
1.理解热位概念 例1下列关于燃料热值的说法中正确的 是() (A)同种燃料,然烧质1越大,热值越大. (B)相同质童的燃料燃烧时,放出热1多 的然料热值大. (C)相同质童的燃料完全燃烧时,放出热 童多的燃料热值大. (D)相同质童的燃料充分燃烧时,放出热 黄多的燃料热值大. 分析理解热值要把握概念中的关键词: (1)“Ik扩确定了每种燃料燃烧的质量相 同,因为燃烧放出的热量跟质量有关; (2)“某种燃料”是指热值跟物质的种类有 关,同种燃料的热值一般相同,与密度和比热容 一样,热值也是物质的一种特性; (3)“完全燃烧”是指燃烧彻底.如果不完 全嫩烧,… 相似文献
4.
多联产发电系统中,进入燃气轮机发电的是化工生产过程中排放的废气,这些气体都是低热值燃料.低热值燃料燃烧不稳定,不利于发电.采用实验方法研究低热值燃料的燃烧特性,通过对气体燃烧的形式和特点、低热值燃料的组成和性质进行分析后确定实验工质.将H2、CH4、CO和N2按照不同的体积百分比配制混合气来模拟低热值燃料,在保证容积热负荷不变的情况下设计出气体燃料进行燃烧实验,最终获得燃料配比、过量空气系数对低热值燃料的扩散燃烧温度分布以及燃烧产物浓度的影响规律. 相似文献
5.
章小卫 《初中生世界(初三物理版)》2010,(Z4)
汽车的心脏是发动机.发动机有汽油发动机和柴油发动机之分.无论是汽油发动机还是柴油发动机,它们都属于内燃式热机(简称内燃机),都是燃烧燃料后通过推动气 相似文献
6.
唐红鹰 《数理化学习(初中版)》2002,(8)
热机是将内能转化为机械能的机器.热机在工作过程中不断燃烧燃料,燃烧燃料放出的热量,其中一部分用来做有用功,另一部分则散失了.内能的散失主要有以下几个方面:燃料燃烧产生的高温为废气带走一部分能量;一部分能量消耗在散热上;还有一部分能量消耗在机械损失上.一部热机,燃烧一定的燃料,用来做有用功的能量越多,它的性能越好.反之,它的性能越差.为了有效地表征热机的这一性能,物 相似文献
7.
《浙江大学学报(A卷英文版)》2019,(6)
目的:1.从辐射能利用角度出发,探究一维固定床煤粉富氧燃烧的辐射能流特性,为固体燃料燃烧能量分质分级转化应用提供参考;2.对比研究半经验模型与人工神经网络模型这两种建模方法,为人工神经网络模型在后续研究中的应用提供参考。创新点:1.提出燃烧光热能量分级转化的概念,为燃烧光热能量分质分级转化系统提供研究基础;2.从辐射能量利用的角度研究煤粉燃烧的辐射能流特性;3.不局限于实验报告,基于实验数据探究2种建模方法,揭示神经网络模型的优势。方法:1.在一维管式炉反应器上进行实验,探究不同燃烧条件下煤粉富氧燃烧的辐射能流特征;2.基于辐射传热理论,通过半经验模型描述煤粉在固定床中燃烧的辐射能流;3.训练神经网络模型来描述实验结果,通过对比2种方法来揭示神经网络模型在预测结果方面的优势。结论:1.固定床煤燃烧过程中的挥发分及煤烟会降低辐射能;可利用低挥发分燃料以及增大氧浓度来提高火焰辐射能比例。2.较高的燃烧温度是提升燃烧辐射能比例最重要的因素;实践中可以通过采用高热值燃料以及烟气回热等方法来提高燃烧温度。3.多联产半焦燃烧辐射能比例高于原煤;可通过煤热解多联产技术与半焦燃烧光热能量分级利用相结合的方式构成新的煤炭高效清洁利用系统。4.人工神经网络不但可以对实验结果进行建模,还能够很好地预测未知工况结果,因此值得在更多的后续研究中使用。 相似文献
8.
9.
循环流化床燃烧技术是20世纪后期发展起来的清洁煤燃烧技术.介绍了循环流化床脱硫技术的进展和发展趋势.CFB 锅炉具有广泛的煤种适应性,可以实现炉内燃烧过程中高效脱硫,减少对环境的污染. 相似文献
10.
张慧娟 《商情·科学教育家》2013,(29)
综述选用PDMS膜在一个间歇式真空渗透汽化系统中,以茶香气模型溶液和茶叶提取物为对象,考查香气物质通量和分离系数,研究采用渗透汽化膜分离技术从茶香气模型溶液和茶叶提取物回收茶香气物质.结果表明,通过实验获得茶叶香气做出显著贡献的物质,即为反式-2-己烯醛,芳樟醇,顺式-3-己烯醇,3-甲基丁醛,2-甲基丙醛,苯甲醇,苯乙醛,α和β-紫罗兰酮,其中β-紫罗兰酮,反式-2-己烯醛,芳樟醇,顺式-3-己烯醇,3-甲基丁醛有很好的选择透过性,而苯乙醛,2-甲基丙醛,苯甲醇选择性略差.总之,渗透汽化膜分离技术是一个很有效的分离方法,它可在温和的条件下,可实现对茶香气物质的回收. 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
13.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
14.
15.
16.
《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
17.
陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
18.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
20.
《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献