基于“此时此地”解决大气污染的实践策略——以乌鲁木齐市实践热电联产项目为例

热电联产通常是指同时生产电、热能的工艺过程,较之分别生产电、热能方式节约燃料。同时,热电联产不仅大量节能,还可以改善环境条件,提高居民生活水平。笔者以乌鲁木齐市为例,说明热电联产可以很好的解决城市冬季采暖所带来的大气污染问题。     

热电联产型供热企业作业成本管理研究（一）

我国华北地区,冬季天气较为寒冷,为百姓提供温暖、舒适环境已经成为了供热企业每年冬季的一项重要工作任务。也是政府部门较为重视的一项工作。本文着重围绕着热电联产型供热企业的成本管理展开研究。通过对热电联产型供热企业成本管理现状的分析,结合作业成本管理理论,探讨热电联产型供热企业在成本管理方面存在的问题,从而解决困扰供热企业成本管理的难题。将理论与热电联产型供热企业的实际情况相结合,探讨热电联产型供热企业在成本管理方面存在的问题,从而解决困扰供热企业成本管理的难题。     

热电联产工程中的燃气配套技术探讨

<正>1热电联产的概念和对环保的积极意义热电联产,简称CHP(combined heat and power),是指电厂在生产电力的同时,利用做过功的工艺过程汽或者乏汽同时对外供热的生产工程。热电联产可以有效地利用余热,提高电厂的总热效率。热电联产在我国北方地区采暖季节需要提供采暖的热源,可以减少手烧炉和工业锅炉的使用。在南方地区主要用于夏季需要提供以热源为驱动力的制冷负荷,目前大部分采用分户式制冷的方式。热电联     

城市集中供热方案的综合评价

本文以通辽市某小区集中供热系统为例,采用层次分析法,建立集中供热系统综合评价体系,涵盖系统的经济效益、社会效益、节能效益、环境效益,对热电联产供热系统与热泵供热系统进行综合评价。结果表明,热泵供热系统与热电联产集中供热系统综合权值分别为0.562与0.438,证明热泵供热模式优于热电联产集中供热系统,具有广泛的应用前景。     

企业自备热电厂的节能性分析

以余姚市某化纤企业自备热电厂热电联产系统为研究对象,对其热、电负荷做了计算,同时用标准煤耗量和总热效率2个指标对系统进行节能性分析。分析结果表明:热电联产系统节能性要优于分产系统,实施热电联产后全厂总热效率提高27.3%,在企业年生产总量不变的条件下,年节约标准煤18125.55t,极大地节约运行成本。文章最后还指出该系统在夏季运行时热负荷减少导致发电量减少,并提出将系统改进为热电冷联产系统的建议。实行热电冷联产后,系统总热效率较原来夏季热电联产系统总热效率提高24.7%,系统节能性进一步提高。     

长江以南部分地区鼓励分布式能源等方式采暖

正本刊讯国家发展改革委4月18日发布热电联产管理办法,提出实现北方大中型以上城市热电联产集中供热率达到60%以上,20万人口以上县城热电联产全覆盖。夏热冬冷地区(包括长江以南的部分地区)鼓励因地制宜采用分布式能源等多种方式满足采暖供热需求。热电联产是指发电厂既生产电能,又利用产生的蒸汽对用户供热的生产方式,较之分别生产电、热能的方式可以节约能源,提高效率。管理办法规定,热电联产规划以满足热力需求为首要任务,同步推进燃煤锅炉和落后小热电机组的替代关停。根据管理办法内容,严寒、寒冷地区(包括秦岭、淮河以北,新疆、青海)优先规划建设以采暖为主的热电联产项目,替代分散燃煤锅炉和落后小热电     

基于热力学第一定律的热电联产节能分析

以热力学第一定律为基础,通过建立热电联产和热电分产的能耗分析模型,研究了两者的供热和发电标准煤耗量差,进而得到热电联产节能的最小热电比。根据最小热电比,分析研究得到了热电联产供热最小抽气量和最佳热效率,为热电厂的节能改造和合理运行提供了理论基础。     

生物质热电联产项目消防对策

以某生物质秸秆直接燃烧热电联产工程为例,介绍秸秆直接燃烧发电的生产工艺及主要火灾危险。针对其工艺特点和消防需求,从生产过程、消防布局、防火分隔、疏散、自动灭火设施、火灾监控等方面提出消防安全对策,提高热电联产项目的消防安全水平。     

硅酸盐相图在水泥生产中的应用

硅酸盐相图在水泥生产中的应用经宝年（山西建材学校）硅酸盐相图就是用几何图形描述，用物理化学的相平衡观点，将硅酸盐物质在不同组成不同温度达到相平衡时的相组成的实验结果加以整理绘成的几何图形。从形象化的相图上，我们可以看出系统在一定的组成、温度、压力下当...     

热电联产在中小型造纸工艺中的应用

一、前言 七十年代初期,我国较广泛地开始采用工业锅炉裕压发电,即热电联产,但各地发展极不平衡。八十年代以来,随着国民经济的高速发展,能源开发利用成为企业生产的重要环节,热电联产即是节能挖潜的一个重要技术措施,本文就热电联产在中小型造纸工艺中的应用,结合呼和浩特造纸厂的实际情况,论述几个问题。     

不同类型盐渍土固化体的干缩与湿胀特性

采用三种固化剂对高含盐量的氯盐盐渍土和硫酸盐盐渍土进行固化,研究了它们的干缩和湿胀特性。结果表明,用矿渣和粉煤灰取代部分水泥,随后又增加粉煤灰的比例,可以连续降低固化土的干缩应变和干缩系数。矿渣和粉煤灰取代水泥后,水化活性减弱,产物减少,同时,体系内Ca2+的浓度降低,盐渍土中所含NaCl和Na2SO4对化学反应的促进作用减弱,化学反应程度以及由此引起的自由水到结合水的转化、孔隙特征的变化的差别缩小,因此,盐分引起的固化土的干缩应变和干缩系数的差别缩小。Na2SO4对固化土干缩应变和干缩系数的提高作用比NaCl明显。在低钙体系中,NaCl的物理作用比化学作用更突出。含NaCl的固化土试件在吸湿阶段具有明显的吸潮特性,但并不引起较大的膨胀。残存在土体中的Na2SO4在吸湿阶段可能发生剧烈膨胀而导致土体发生严重开裂。     

含氯硫酸盐渍土中硫酸钠结晶量理论分析研究

硫酸盐渍土产生盐胀变形的主要原因是土中固相或液相硫酸钠结合水分子析出芒硝晶体,盐分体积大幅增加而导致的。基于已有测试数据,采用回归分析方法建立了硫酸钠溶解度模型,在理想条件下分析计算了降温条件下土体内硫酸钠的结晶量,探讨了硫酸钠结晶量随含盐量、含水率、氯化钠浓度和土体环境温度的变化关系。研究表明,含盐量和含水率对硫酸钠结晶量的影响存在一个临界值,氯化钠浓度对硫酸钠结晶量的影响取决于土体内的含盐量和含水率组合条件,有利组合下加入适量氯化钠能够抑制土体内硫酸钠的结晶量,不利组合下加入氯化钠反而会促使土体内硫酸钠结晶量增大,不利于盐胀变形的控制。硫酸钠结晶量严重依赖于环境温度,若初始状态下土体的温度较低,部分硫酸钠已经结晶析出,温度进一步降低时硫酸钠的结晶量则相应减少。     

Water and salt phase change in sodium sulfate soil based on differential scanning calorimetry

Strong salt expansion and frost heave are induced to make the infrastructure in the salted region damaged with water or salt phase change at low temperature. Laboratory test based on differential scanning calorimetry is used to investigate salt and water phase transformation and their crystallization mechanism in sodium sulfate soils and solutions. During the experimental process, crystallization heat release, crystallization period and supercooling are measured. According to the conservation principle of mass and heat, salt and ice crystallization are separated, and unfrozen water content is calculated at different temperatures. Moreover, variations of unfrozen water content, as well as the supercooling degree of sodium sulfate soils with different size are compared and analyzed based on heterogeneous nucleation theory. The results demonstarte occurance of the ice crystallization before salt crystallization in minor soil samples; however, salt crystallization appears first in pure solution at high concentration. The interval at which the ice and salt crystallization begin decreases as the salt content increases, and the supercooling decreases as the salt content or sample size increases. Additionally, water freezing in small soil samples is more difficult than that in larger soil samples, and the unfrozen water content increases as the salt content or sample size decreases.     

Studies on marine biological filters: Model filters

Model systems of 401. capacity were used to study chemical changes which affected buffering in continuously recycled sea water and which restricted nitrification in percolating biological filters at 28°C.

Sustained hydrogen ion production during the microbial oxidation of ammonia to nitrite caused continuous carbon dioxide formation from carbonate and bicarbonate. The carbon dioxide was steadily lost to the air through vigorous aeration, leaving < 2 mg inorganic carbon 1⁻¹ in the sea water. Oxidation of nitrate to nitrate did not significantly reduce pH nor deplete buffer capacity.

Ammonia oxidation was severely inhibited by the combination of low pH and dissolved inorganic carbon levels, but similar low levels of pH produced when carbon dioxide was bubbled through the water had only a moderate effect. Inhibition could be rapidly overcome or prevented by additions of inorganic carbon, sodium hydroxide or sodium dihydrogen phosphate.

Values recorded for the maximum specific growth rate of Nitrosomonas and Nitrobacter were 0.53 and 0.81 d⁻¹ respectively. The corresponding generation or doubling times were calculated to be 31.4 and 20.5 h.

Some evidence was found for the uptake of phosphate and the formation of hydroxylamine during nitrification.     

硫酸盐渍土未相变含水率与温度关系研究

以硫酸盐渍土为研究对象,从理论上建立了冻结温度以上未相变含水率与温度的关系,并通过室内试验测试了硫酸盐土体及对应溶液中盐晶体初始析出温度和硫酸盐渍土未相变含水率在不同温度环境下的变化。从土体降温温度曲线、不同温度下核磁共振信号强度分析了温度对未相变含水率的影响。研究结果表明:在特定降温速率下,十水硫酸钠晶体析出存在滞后性,初始析出温度均低于其饱和浓度所对应的温度,并随着初始含盐量的减小,初始析出温度大幅度降低,且与土体比较,溶液中盐晶体易于析出;土体中十水硫酸钠晶体的析出造成含水率的减小明显大于溶液中晶体的析出引起的减小,且随着温度递降,未相变含水率递减;冻结温度以下,高含盐量的硫酸盐渍土未冻含水率与温度呈指数规律减小,-10℃以下,其含水率不再变化。对于低含盐量硫酸盐渍土,冻结温度以下其未冻含水率随温度降低同样按指数规律减小,且随着含盐量的增加,土体的含水率有所增加。     

钠盐激发钢渣水泥的早期水化特性及动力学

采用钠盐作为激发剂,通过水化热测定、扫描电镜(SEM)分析和水化动力学模拟,研究了不同钠盐激发钢渣水泥的早期水化进程、水化特性及其水化动力学.结果 表明:钠盐掺入不影响钢渣水泥的水化进程,掺与不掺钠盐的钢渣水泥水化进程均分为起始快速放热期、诱导期、加速期、减速期和衰减期5个阶段;加速期水化反应由成核反应控制,属自催化反...     

高性能改性密胺减水剂的研究与开发

采用对氨基苯磺酸钠替代传统的亚硫酸盐作为磺化剂,制得的改性密胺减水剂克服了传统密胺减水剂减水率偏低、保坍性能差等缺点,并且对泥土含量的敏感性大大降低。使用对氨基苯磺酸钠制备密胺减水剂的合成工艺由传统的"四步法"改进为"三步法",操作更为简单可控。通过对比亚硫酸盐和对氨基苯磺酸钠2种磺化剂所制备密胺减水剂的性能,分别对合成过程中的磺化剂用量进行了系统的探索研究。与萘系、脂肪族、氨基磺酸盐系等缩聚型减水剂的性能对比,改性密胺减水剂具有优异的分散和分散保持性能。     

分散性粘土判别试验研究

应用碎块、针孔、双比重计、孔隙水可溶盐和交换性钠百分比等五种试验方法,结合物理化学性质和矿物成分分析,对西郊、三坪两水库大坝心墙土样进行了多种方案的分散性试验及长期渗流条件下的渗透变形试验和盐分运移试验。认为三坪土样中钠离子的分散作用小于西郊土样,钙镁离子的抑制分散作用大于西郊土样,并且三坪土样中的蒙脱石含量低于西郊土样,因此三坪土样属于非分散性土,西郊土样属于过渡型土。土样施工用水对土样的分散性鉴定结果影响较小,而冲蚀用水对土样的分散性鉴定结果产生大的影响。在长期的渗流条件下土样中钠离子随水流易迁移,河水中的钙离子含量大,进入土体后能抑制土样的分散性,促使土体向非散性的方向发展。结果表明土样中钠离子和钙镁离子含量多寡和相对含量对粘土分散性具有重要的作用,蒙脱石的存在是粘土分散性的重要因素,河水对粘土分散性能将产生显著影响。     

Systematic salt effects in the automated determination of nutrients in seawater

The Bran + Luebbe TRAACS continuous flow analyser, commonly used for the determination of nutrients in seawater, primarily employs standard methods that have been modified and adapted for automated use. The analyser is fitted with self aligning spectrophotometric flow-cells with parallel optical ends of uniform thickness. As the light beam strikes both ends of the flow-cell perpendicularly, there is no refraction therefore no spurious absorbance caused by changes in the refractive index of the flow-cell contents. Investigation of methods for the determination of ammonia, nitrate, nitrite, orthophosphate, soluble reactive silica and urea, using TRAACS, confirmed that this was the case. Also, for the methods assessed, the absorbance signal was not biased by either sample turbidity or wetting agents. Chemical interference from salt was assessed by analysing nutrient spiked solutions, over the 0–35 ppt salinity range, relative to working calibration solutions prepared using demineralised water. A major salt effect which caused an apparent decrease in concentration, was detected over the analytical working ranges in the ammonia and nitrate methods. The salt effect results from a chemical interference which causes the production of reaction products to vary as a function of salinity. The salt effect is totally unrelated to refraction and produces a concentration error in the ammonia and nitrate methods up to 35 and 25% respectively. The degree of salt effect was shown to be dependent on both the salinity and true nutrient concentration of the sample. Over the salinity range 8.75–35.00 ppt, corrective equations were derived for ammonia and nitrate to express the true nutrient concentration in terms of the observed concentration and the salinity of the solution. Within the range 0–8.75 ppt no correction was required for ammonia wheras the nitrate showed a 3.5% increase in apparent concentration at 8.75 ppt. The orthophosphate, soluble reactive silica, urea and nitrite methods showed no significant salt effect as the coefficient of variation (CV) of the observed nutrient concentrations over the 0–35 ppt salinity range was within the accepted CV or analytical precision of the methods. The ammonia and nitrate corrective equations were applied in assessing the true nutrient content of “depleted” or low nutrient seawater, used in the preparation of working calibration solutions, after analysing relative to working calibration solutions prepared in demineralised water.     

Experimental study on thermo-chemical phenomena during interaction of limestone concrete with liquid sodium under inert atmosphere

Sodium leak in fast breeder reactor, either from pipe in inert equipment cells or inside the reactor cavity may come in contact with the limestone sacrificial layer on structural concrete. Experimental studies are carried out to investigate thermal and chemical impact of sodium on the limestone concrete under different test conditions. Sodium pool is maintained at different temperature on the test blocks placed in leak tight test chamber. The temperatures at different locations, pressure, release of hydrogen and oxygen gas are monitored online during the experiments. On-set time and residence period for energetic thermal transients (ETT) along with peak and average heat generation rates are evaluated. Chemical parameters such as rate and extent of water release from concrete, sodium consumption, sodium hydroxide production and sodium emission into argon atmosphere are also elucidated. Preliminary analysis of test results revealed that when hot sodium at 500 °C reacts on cold concrete block, it monotonically cools down with low degree of interaction. However, supply of external heat to sodium pool triggers considerable reaction with or without occurrence of ETT phase.