超净电袋复合除尘技术实现超低排放

近年来，超低排放政策逐渐出台，部分地方政府和电力集团甚至要求烟尘排放达到5 mg/m3以下，迫使除尘技术进行工艺改进。介绍了珠海电厂700MW燃煤机组电除尘器采用超净电袋复合除尘器改造后，实现烟尘排放浓度〈5 mg/m3的超低排放，探讨超净电袋复合除尘器在满足超低排放政策中的技术优势。     

600 MW机组除尘器升级改造及效益评价

元宝山发电有限责任公司2号600 MW机组配套电除尘器由于设计效率低、燃烧煤种变化、设备老化等多方面原因，除尘效率下降，除尘器出口烟尘排放浓度超标严重。为了满足新的《火电厂大气污染物排放标准》的要求，对元宝山发电有限责任公司2号机组配套电除尘器进行升级改造，将原有的4台四电场静电除尘器增效改造为4台电袋复合式除尘器。通过电除尘器的改造，降低了除尘器出口粉尘排放浓度，提高了除尘效率，保证了2号机组电除尘器的安全稳定运行。     

电袋除尘器改造在半干法烟气脱硫中的应用

介绍了包头第二热电厂200MW机组半干法脱硫系统配套电除尘器的情况，由于燃用煤质的改变及环保要求的提高，原电除尘器出口粉尘浓度无法满足排放要求，需要对其进行改造。通过经济、技术对比分析，确定采用电袋除尘器改造方案。改造后粉尘排放浓度降至30mg／m^3。满足环保要求。     

除尘器电源与除尘效率

本文说明除尘器电源对电除尘器的影响。从工厂实测的大量数据显示：高压恒流源能改善２电厂，化工，水及冶金等工业电除尘器的除尘效率。     

韩国除尘技术在改造项目中的应用

随着环保法规的日益严格，国电邯郸热电厂9号、10号炉的电除尘器存在除尘效率不够、烟尘排放超标的现象，为此，电厂引进韩国先进的除尘技术，对9号、10号炉的电除尘器进行了技术改造，并取得预期的效果。     

燃煤机组静电除尘器的运行状况分析与优化

分析了我国现有燃煤机组静电除尘器的运行情况,研究了静电除尘器的造价、运行成本、出口粉尘含量等各方面情况,进而分析了除尘器入口粉尘含量、漏风率、二次电压、运行温度和湿度对除尘效率的影响.结果表明,除尘器入口粉尘含量和漏风率的增加不利于除尘器的运行,而二次电压和湿度在一定范围内增大有利于除尘效率的提高,电除尘器只能在一定温度区间能达到高效运行.提出相应的优化措施,为电除尘器技术改造提供参考.     

湿式电除尘器技术分析

近期全国多地雾霾频发，空气质量恶化，为改善空气质量，国家出台了新的火电厂大气污染物排放标准，加强对于烟尘、SO2、NOx的排放控制。为满足新的排放标准，解决现运行电厂存在的细微颗粒物排放不达标、石膏雨以及蓝烟问题，湿式电除尘器作为控制大气复合污染物的精处理装置，可以作为烟囱前的最后一道技术把关。分析了湿式电除尘器除尘机理、结构特点以及布置方式，论述了国内外应用情况，并在此基础上就技术性和经济性两方面与干式电除尘器、袋式除尘器和电袋除尘器进行分析比较，可为电厂选型提供参考。     

电袋复合除尘技术研究

目前电除尘器和袋式除尘器是烟气净化的两种主要设备，电袋复合除尘器是一种高效的除尘技术，它结合两种类型除尘器的优点，并成功的应用于燃煤电厂烟气的净化，其排放浓度可长期稳定在30mg／m3以下。     

谏壁发电厂10号炉电除尘器改造

分析了谏壁发电厂10号炉原电除尘器除尘效率低的原因，介绍了该电除尘器的改造方案及依据。除尘器改造后烟尘排放质量浓度仅为41．5mg／m^3，大大削减了电厂烟尘排放量，增强了企业的发展后劲。     

移动电极电除尘器除尘效率的计算

移动电极静电除尘器通过清灰刷除掉阳极板上收集的粉尘,阳极系统为移动电极（即作回转运动的集尘极）阳极板呈带条状,固定在链条上,随链轮转动。移动电极静电除尘器有效克服了困扰常规电除尘器对高比电阻粉尘的反电晕及振打二次扬尘等问题,大幅度提高了除尘效率。提供常规固定电极除尘区与移动电极除尘区联合使用的除尘器除尘效率计算公式。     

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.     

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.     

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%。     

GGH换热元件堵塞原因分析及解决措施探讨

分析了湿法脱硫系统中GGH换热元件堵塞的原因及对系统运行的影响,并结合目前GGH使用状况给出了解决措施,为脱硫系统安全运行提供参考。     

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。     

不同类型清水剂处理油田含聚污水的效果对比

考察了阳离子型CWC-14、非离子型NQS-01和阴离子型AQS-08 3类清水剂对油田含聚污水的处理效果,对比了它们的作用特点和絮体性能。实验结果表明:在清水剂加入量350 mg/L、处理温度65℃、搅拌转速300 r/min、搅拌时间5 min的条件下,CWC-14、NQS-01和AQS-08对含聚污水的除油率分别为98.8%、98.0%和99.4%;NQS-01受处理温度、搅拌条件影响较大;CWC-14受污水中聚合物质量浓度影响最大。清水剂的絮体特点与其作用机理有关,CWC-14的絮凝速率最快,起效时间最短,絮体呈黏性大块状;NQS-01的絮凝速率最慢,起效时间最长,絮体呈浮油状;AQS-08的絮凝速率和起效时间适中,絮体呈松散状、流动性好。对比结果表明,非阳离子型清水剂可有效避免油田含聚污水处理过程中的黏性油泥问题。     

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.