燃煤电厂烟气脱硝技改前期工作要点分析

国家“十二五”期间将严格控制氮氧化物的排放。介绍了火电厂烟气脱硝技改主要前期工作,并对其中的要点注意事项及协同工作进行分析探讨,以尽可能避免脱硝工程建设中出现“十一五”烟气脱硫工程中的各种弊端,保证脱硝工程建设质量和性能保证。     

专利文摘

复合双级烟气脱硫除尘装置该实用新型专利涉及一种复合双级烟气脱硫除尘净化装置。该装置由一、二、三部分组成:第一部分为陶瓷多管除尘器或静电除尘器,对烟气进行一级除尘,除去烟气中90%-99%的粉尘;第二部分为文丘里干燥吸收塔,烟气中的二氧化硫与脱硫液反应被吸收,实现一级脱硫;第三部分为袋式脱硫除尘器,除去脱硫反应生成物和对烟气中的细小粒级进行二次除尘;烟气中未被除去的二氧化硫气体实现二级脱硫。该实用新型专利的优点是:工艺流程简单,设备最佳匹配组合,钙硫比低,脱硫除尘效率高,系统占地面积小,维护工作量少,运行费用低,引风机不带水粘灰,排烟温度高,没有蒸汽“白雾”现象。脱硫生成物为干粉剂,便于贮运和综合利用。/CN2633403,2004-08—18     

石灰石/石膏湿法烟气脱硫装置的除尘性能

通过对国电太原第一热电厂16号50MW机组石灰石／石膏湿法烟气脱硫装置的除尘性能分析，研究脱硫装置的除尘机理，找出影响FGD除尘性能的主要因素，为烟气脱硫工程设计提供参考。     

用纯碱厂废碱液进行烟气脱硫

分析了旋流板塔式除尘脱硫装置的结构和工作原理,探讨了利用废碱液进行烟气除尘脱硫的主要影响因素,并确定了最佳操作条件。试验结果表明,利用纯碱厂排放的废碱液（一次盐泥）进行锅炉烟气脱硫可以取得较高的净化效率,不仅可降低脱硫剂费用,而且可消除废碱液带来的污染。     

烟气除尘脱硫一体化产物氧化特性研究

简述了石灰湿法烟气除尘脱硫一体化的工艺过程,通过工程试验并结合实验室小型试验,重点探讨石灰湿法烟气除尘脱硫一体化条件,脱硫产物亚硫酸盐的氧化过程及其影响因素。     

应用Matlab仿真烟气脱硫除尘过程

介绍了Matlab语言在烟气脱硫除尘过程仿真中的应用.根据试验得到不同参数值时烟气的脱硫、除尘效率,用MATLAB对数据进行最小二乘法拟合,得到方程式.已知烟气风量和不同阶段的温度、进口和达标污染物浓度,根据拟合得到的方程式(乘以修正系数),用Matlab编程可计算出污染物满足达标情况下的参数值.结果表明,该程序简单、易读、使用方便、功能强大、精度高,由此证明了基于Matlab语言开发烟气脱硫除尘设计软件的可行性与优越性.     

冲天炉烟气除尘

采用湿法除尘,在烟气管道内设置喷嘴,使烟气充分加湿和降温后再进入立式文丘里,旋流析除尘器,消除了ＣＯ爆炸危险,在冲天炉上部烟囟顶端设安全２盖板,以保证生产的正常进行;烟气经湿式除尘后达到排放标准。     

燃煤机组除尘设施能耗状况及指标评估

针对电力行业燃煤烟气三种主流除尘设施电除尘器、袋式除尘器、电袋复合除尘器,研究了其运行过程中主要组件的能源消耗规律及数据监测方法,提出了除尘设施能耗比对的2个参数,即用电率和比电耗。监测数据和统计表明,同级别机组电除尘能耗低于袋式除尘和电袋复合除尘,比电耗随机组容量变化梯度变化值不显著,除尘设施电源侧技术改进有助于降低除尘设施能耗。     

泡沫玻璃砖在烟囱防腐中的应用

火电厂燃煤烟气中存在一定量的SO3,会显著降低烟气的酸露点。由于湿法脱硫后烟温低于酸露点,烟气中的SO3与水蒸汽形成的硫酸蒸汽会凝结下来,造成混凝土烟囱的低温腐蚀。以2×135MW机组烟气脱硫技改工程湿烟囱防腐为例,详细介绍了烟囱内衬泡沫玻璃砖防腐的施工工序、技术要求及注意事项。     

石横一期烟囱冲洗水及排液系统改造

介绍了石横电厂一期烟气脱硫技改项目中烟囱及入口烟道排液系统改造情况,论述了烟囱及烟道排液系统改造要点、运行方式,提出了烟囱排液系统的改造方案。     

Review of the kinetics of alkaline degradation of cellulose in view of its relevance for safety assessment of radioactive waste repositories

The degradation of cellulose (a substantial component of low- and intermediate-level radioactive waste) under alkaline conditions occurs via two main processes: a peeling-off reaction and a basecatalyzed cleavage of glycosidic bonds (hydrolysis). Both processes show pseudo-first-order kinetics. At ambient temperature, the peeling-off process is the dominant degradation mechanism, resulting in the formation of mainly isosaccharinic acid. The degradation depends strongly on the degree of polymerization (DP) and on the number of reducing end groups present in cellulose. Beyond pH 12.5, the OH^- concentration has only a minor effect on the degradation rate. It was estimated that under repository conditions (alkaline environment, pH 13.3-12.5) about 10% of the cellulosic materials (average DP = 1000-2000) will degrade in the first stage (up to 10⁵ years) by the peeling-off reaction and will cause an ingrowth of isosaccharinic acid in the interstitial cement pore water. In the second stage (10⁵-10⁶ years), alkaline hydrolysis will control the further degradation of the cellulose. The potential role of microorganisms in the degradation of cellulose under alkaline conditions could not be evaluated. Proper assessment of the effect of cellulose degradation on the mobilization of radionuclides basically requires knowing the concentration of isosaccharinic acid in the pore water. This concentration, however, depends on several factors such as the stability of ISA under alkaline conditions, sorption of ISA on cement, formation of sparingly soluble ISA-salts, etc. A discussion of all the relevant processes involved, however, is far beyond the scope of the presented overview.     

Study of Aging Characteristics of Ternary Blends of Polyethylenes—II

Six film samples of low-density polypropylene (LDPE)/linear LDPE (LLDPE)/high-density polypropylene (HDPE) with varying ratios of LDPE (20–45 ... wt%) and LLDPE (25–50 wt%) having a fixed amount of HDPE at 30 wt% were prepared by blown film extrusion technique. The samples were aged at four different temperatures, 55°, 70°, 85°, and 100°C, for four different time periods in the interval of between 150 hours and up to 600 hours. The change in the structure of various constituents and the formation of various oxygenated (peroxy and hydroperoxy) and unsaturated groups during thermo-oxidative degradation was discussed by infrared spectroscopy. The visiosity-average molecular weight was found to have decreased slowly in the initial aging hours and temperatures, whereas it decreased by 10% with its previous value tensile strength that is, 100°C when aged for 600 hours. The tensile strength of the sample first increased by 67% at 55°C and 89% at 70°C up to 450 hours, whereas the values increased by 52.5% at 85°C and 33.9% at 100°C when aged for 150 hours and then decreased. The percentage elongation at break increased by 2.7% at 55°C and 10.7% at 70°C for 150 and 300 hours of aging, respectively, whereas the percentage decreased when aged at 85°C and 100°C for up to 600 hours of aging. The values of gel content (percent) increased and initial degradation temperature decreased with aging time and temperature.     

Determination of the Burning Characteristics of a Slick of Oil on Water

The burning rate of a slick of oil on a water bed is characterized by three distinct processes, ignition, flame spread and burning rate. Although all three processes are important, ignition and burning rate are critical. The former, because it defines the potential to burn and the latter because of the inherent possibility of boilover. Burning rate is calculated by a simple expression derived from a one-dimensional heat conduction equation. Heat feedback from the flame to the surface is assumed to be a constant fraction of the total energy released by the combustion reaction. The constant fraction (χ) is named the burning efficiency and represents an important tool in assessing the potential of in situ burning as a counter-measure to an oil spill. By matching the characteristic thermal penetration length scale for the fuel/water system and an equivalent single layer system, a combined thermal diffusivity can be calculated and used to obtain an analytical solution for the burning rate. Theoretical expressions were correlated with crude oil and heating oil, for a number of pool diameters and initial fuel layer thickness. Experiments were also conducted with emulsified and weathered crude oil. The simple analytical expression describes well the effects of pool diameter and initial fuel layer thickness permitting a better observation of the effects of weathering, emulsification and net heat feedback to the fuel surface. Experiments showed that only a small fraction of the heat released by the flame is retained by the fuel layer and water bed (of the order of 1%). Ignition has been studied to provide a tool that will serve to assess a fuels ease to ignite under conditions that are representative of oil spills. Two different techniques are used, piloted ignition when the fuel is exposed to a radiant heat flux and flash point as measured by the ASTM D56 Tag Closed Cup Test. Two different crude oils were used for these experiments, ANS and Cook Inlet. Crude oils were tested in their natural state and at different levels of weathering, showing that piloted ignition and flash point are strong functions of weathering level.     

Calculation of carbon balances for evaluation of the biodegradability of polymers

Establishing carbon balances has been proven to be an applicable and powerful tool in testing biodegradability of polymers. In controlled degradation tests at a 4-L scale with the model polymer poly(-hydroxybutyrate) (PHB), it was shown that the degree of degradation could not be determined with satisfactory accuracy from CO₂ release alone. Instead, the course of degradation was characterized by means of establishing carbon balances for the degradation of PHB withAcidovorax facilis and a mixed culture derived from compost. Different analytical methods for determining the different carbon fractions were adapted to the particular test conditions and compared. Quantitative determination of biomass and residual polymer were the main problems in establishing carbon balances. Amounts of biomass derived from protein measurements depend strongly on assumptions of the protein content of the biomass. Selective oxidation of biomass with hypochlorite was used as alternative, but here problems arose from insoluble metabolic products. Determination of soluble components with the method of chemical oxygen demand (COD) also includes empirical assumptions but seems acceptable if the dissolved carbon fraction is in the range of some 10% total carbon. Results confirm both analytical assays and theoretical approaches, in ending up at values very close to 100%, within an acceptable standard deviation range under test conditions comparable to standard test practice.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.     

鼓泡式反应器高径比对氨法烟气脱碳性能的影响

以N2和CO2混合气模拟燃烧烟气,研究了鼓泡反应器的高径比以及反应条件对氨法烟气脱碳性能的影响。实验结果表明:在相同高径比的条件下,CO2吸收率随氨水质量分数的增加、反应温度的升高而逐渐增大,随进气CO2体积分数和模拟烟气流量的增加而逐渐减小;CO2吸收率随高径比的增加而增大,在高径比为3.98、氨水质量分数为28%、进气CO2体积分数为10%、模拟烟气流量为1.0L/min、反应温度为40℃的条件下,CO2吸收率最高可达100%。     

Model of technological alternatives of production of sodium chromate (VI) with the use of chromic wastes

This article presents a mathematical model which describes the sodium chromate (VI) production process with the use of chromic waste as a substitution of natural raw materials. This model is a function of selected process parameters common for all of the examined alternatives and based on equations of material balance. Optimization of the elaborated technological alternatives of the production process with use of recycling of chromic waste has been evaluated by determining the extreme value of the quality indicator WJ. This indicator defines the quantity of waste created in the process. Optimization results enabled the selection of the optimal technological solution from all of the alternatives possible for use in industrial practice. Negative values of the indicator prove that there is the possibility of introducing to the process a larger quantity of waste than the one obtained in the process and transported to the storage heaps.     

Structure-biodegradation relationships of polymeric materials. 1. Effect of degree of oxidation on biodegradability of carbohydrate polymers

The biodegradability of oxidized starch and inulin has been studied in relation to the degree of periodate oxidation to dialdehyde derivatives, by measuring oxygen consumption and mineralization to carbon dioxide. A higher degree of oxidation of dialdehyde starch and dialdchyde inulin results in a lower rate at which the polymers are biodegraded. It is demonstrated that the biodegradation rate of dialdehyde inulin derivatives decreases more than that of equivalent starch derivatives. The differences in biodegradation behavior between dialdehyde starch and dialdehyde inulin, resulting from comparable modifications, are discussed in terms of conformational structure.     

化学品生物降解性的评价与预测

介绍了有机化学物质生物降解性的测定方法及其预测方法研究概况，并讨论了生物降解性评价的发展前景。     

Mechanism of Microbial Degradation of Slow-Release Fertilizers

Methyleneureas are condensation products of urea and formaldehyde of different molecular mass and solubility; they are used in large amounts both as resins, binders, and insulating materials for industrial applications, as well as a slow-release nitrogen fertilizer for greens, lawns, or in bioremediation processes. In the present study, the microbial breakdown of these products was investigated. The nitrogen was released as ammonia and urea, and the formaldehyde released immediately oxidized via formiate to carbon dioxide. The enzymatic mechanism of metabolization of methyleneureas was studied in microorganisms isolated from soil, which were able to use these compounds as the sole source of nitrogen for growth. A strain of the Gram-negative bacterium Ralstonia paucula (formerly Alcaligenes sp. CDC group IVc-2) completely degraded methylenediurea and dimethylenetriurea to urea, ammonia, formaldehyde, and carbon dioxide. The enzyme initiating this degradation (methylenediurease) was purified and turned out to be different from the previously described enzyme from Ochrobactrum anthropi with regard to its regulation of expression and physicobiochemical properties. Fungal degradation of methyleneureas may occur via the formation of organic acids, thus leading to a nonenzymatic degradation of methyleneureas, which are unstable under acidic conditions.     

600 MW机组低压转子叶片裂纹分析

针对某台600 MW亚临界参数汽轮机低压转子的末三级叶片(2Cr12NiMo1W1V钢)出汽侧裂纹进行了宏观形貌观察、化学成分分析、金相组织分析、室温冲击韧性试验、硬度试验,并对断口进行了扫描电镜及能谱分析。结果表明：此次开裂的低压转子叶片,是由于其化学成分Mo元素含量低于标准要求,导致材料的KISCC降低,以及硬度偏低造成裂纹扩展所需的外界启动应力降低,进而在运行过程中拉应力和湿蒸汽的氧化腐蚀共同作用下,发生了应力腐蚀开裂。