等离子点火燃烧技术在电厂节能和环保方面的应用

介绍了等离子点火技术在浙江长兴电厂3号炉上的应用.自电厂进行等离子点火装置改造并正式投运以来,取得了良好的经济效益和节能效果,环境效益也十分显著,实现了低负荷断油燃烧,节油率达90%左右,1台300 MW机组可节约燃油成本180 万元/a.     

机械雾化微油点火小油枪在300 MW亚临界控制循环锅炉中的应用

针对传统电站锅炉点火油枪耗油量大、燃尽率低、污染大等问题,阐述了微油点火燃烧器的工作原理、结构和辅助系统,介绍了微油点火在莱城电厂的实际应用情况,并对运行中存在的问题,提出了相应的改进措施。实践证明,微油点火改造后,节油率达到了86%,为电站锅炉节油降耗提供了技术支持。     

烟气连续监测系统可靠性分析

系统地介绍了200型烟气连续监测系统的对比试验方法，烟气连续监测系统的可靠性等.     

固相萃取—离子色谱法测定多种水样中丙烯酸

建立了一种离子色谱法测定不同类型实际水样中丙烯酸的方法.考察了样品采集和保存、样品前处理及色谱条件对丙烯酸测定的影响.实验结果表明:用棕色塑料瓶采集含丙烯酸的实际水样可在-20℃冷冻条件下保存14 d;采用Na型、Ag型、Ba型和C18型固相萃取柱能够有效除去水样中干扰物质;利用AS11-HC型色谱柱,进样量为200μ...     

EE型电除尘器在200MW机组上的应用

介绍了EE型电除尘器在安徽准北发电厂200MW发电机组配套锅炉上的应用情况以及处理高比电阻粉尘的方法。     

改革开车点火工艺减少SO2污染

硫酸生产开车点火造成的SO_2污染,一直是各硫酸厂亟待解决的问题,《化工环保》本期发表了刘少武等三位同志的文章,各自介绍了本厂多年来实施的开车点火方法,在减少 SO_2 对环境的污染方面取得了较好的效果,很值得各硫酸生产厂(或车间)借鉴。过去,各硫酸厂只注重生产系统尾气中排放 SO_2的治理,认为开车点火造成的 SO_2污染微不足道,是不可避免的。这种观点是十分错误的,必须破除,否则,对创建清洁文明工厂和六好企业将是很大的障碍。     

日开发龙卷式垃圾焚烧炉

日本正在研究开发一项新的垃圾焚烧炉技术，它采用气化反应燃烧方式，能够抑制二恶英等有害物质的排放量。 这种新型锅炉叫做“龙卷炉”，垃圾气化后，在炉子的中央部分燃烧，仿佛是由火焰形成的龙卷风，火焰不接触炉体内侧，因此不需要耐火材料，并且炉体分段建造，结构简单，便于搬运和安装。 目前长崎县境内的大学、企业及有关团体成立了“龙卷炉”研究会，并且已经制作出试验炉，这种试验炉每小时可焚烧湿度在50%以下的垃圾200公斤，点火时只需要少量的柴油，以水作为助燃剂，燃烧温度可达1200至1300报氏度。 (张石)     

新型电除尘技术在200MW机组改造上的应用

介绍了国电双鸭山发电有限公司2号炉200MW机组除尘系统改造项目（原水膜除尘器改造为电除尘器）。由于受场地限制,常规结构除尘器难以布置,故采用EEII-G新型电除尘器,该除尘器是在EEII型电除尘器技术基础上进行了优化改进,较好地利用了现场空间,也取得了满意的除尘效果。     

硫酸厂二氧化硫废气排放规律及对环境的影响

在分析硫酸生产工艺的基础上，对硫酸生产的三个特征工况，即点火、封火和正常生产时二氧化硫的排放情况进行了监测，研究了不同工况下二氧化硫的排放规律及对环境的影响范围和程度。     

煤泥-煤矸石混烧技术在沸腾床锅炉上的应用

南桐矿务局电厂11^#锅炉是东方锅炉厂生产的鼓泡床锅炉，型号为DG-35／3．82-M101，属单汽包膜式壁自然循环锅炉，床下风室点火，炉内百叶窗除尘，飞灰回燃，两台给煤机炉前正压给煤，原设计煤种为煤矸石加工的沸腾煤(低位发热量为12．54MJ／kg左右)，采用水膜除尘器除尘。锅炉送风机为9-2614D型，参数为53013m^3／h，12．015KPa，配电机JS-126-4型，225kW。锅炉引风机为4-6816D型，参数为84156—95764m^3／h，2．65-2．71KPa，配电机Y315M2-6型，110kW。     

Determination of the Thermal Efficiency of Pre-boilover Burning of a Slick of Oil on Water

The burning rate of a slick of oil on a water bed 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. The total heat release, as a function of the pool diameter, is obtained from an existing correlation. It is assumed that radiative heat is absorbed close to the fuel surface, that conduction is the dominant mode of heat transfer in the liquid phase and that the fuel boiling temperature remains constant. 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%). The effect of weathering on the burning rate decreases with the weathering period and that emulsification results in a linear decrease of the burning rate with water content.     

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.     

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.     

富拉尔基发电总厂200MW机组除尘器改造

对富拉尔基发电总厂5号炉的设计条件进行了分析，针对燃用低硫煤，飞灰比电阻高，场地较小，除尘效率要求高的情况，在电除尘器的设计上采取有效措施，达到了排放要求。     

Effects of temperature on the release of nutrient elements of solid organic materials under conditions of oversaturation

The effects of temperature on the release of chemical components of six solid organic materials under conditions of oversaturation were investigated in this paper. The six materials were peat moss (PM), weathered coals (WC), charred rice husks (CRH), sawdust (Sd), turfgrass clippings (TC), and chicken manure (CM). Significant differences were observed in the available nitrogen and phosphorus content of the aqueous extracts of organic materials at different temperatures. The available nitrogen content in aqueous extracts of PM and WC at 25 °C was higher than that registered at 15 °C and 35 °C. Available nitrogen content in the aqueous extracts of CRH, Sd, TC, and WC at 35 °C was higher than at 15 °C and 25 °C. The available phosphorus content in the aqueous extracts of organic materials at 35 °C was higher than that available at 15 °C and 25 °C, with the exception of Sd. In addition, the release of available phosphorus in the aqueous solution of organic materials at different temperatures varied constantly for 108 h. The release of potassium (K⁺) and sodium (Na⁺) ions in the aqueous extracts of organic materials was basically steady over time, with the exception of CM. High temperature (35 °C) may significantly hasten the release of K⁺ from organic substrates (except for WC) with low temperatures significantly inhibiting release of K⁺ in Sd and CRH. High temperatures (35 °C) might significantly facilitate the release of Na⁺ in CM and TC. However, no significant differences were manifested in the release of Na⁺ from organic substrates at different temperatures, with the exception of CM and TC. Moreover, no significant differences were observed in the release of calcium, magnesium and iron ions with time, nor were there any significant differences in the contents of iron ions in the aqueous extracts of organic materials at different temperatures. The results indicate that multiple mediums should be pretreated in water for a week before being used for planting. They should be used when all mineral elements of organic materials are steady and ignoring the effect of organic mediums.     

Selection of adsorbents for treatment of leachate: batch studies of simultaneous adsorption of heavy metals

The simultaneous adsorption of copper (Cu), cadmium (Cd), nickel (Ni), and lead (Pb) ions from spiked deionized water and spiked leachate onto natural materials (peat A and B), by-product or waste materials (carbon-containing ash, paper pellets, pine bark, and semi-coke), and synthetic materials (based on urea-formaldehyde resins, called blue and red adsorbents) or mixtures thereof was investigated. The adsorbents that gave the highest metal removal efficiencies were peat A, a mixture of peat B and carbon-containing ash, and a mixture of peat A and blue. At an initial concentration of 5 mg/l for each metal, the removal of each species of metal ion from spiked water and spiked leachate solutions was very good (>90%) and good (>75%), respectively. When the initial concentration of each metal in the solutions was twenty times higher (100 mg/l), there was a noticeable decrease in the removal efficiency of Cu²⁺, Cd²⁺, and Ni²⁺, but not of Pb²⁺. Langmuir monolayer adsorption capacities, q_m, on peat A were found to be 0.57, 0.37, and 0.36 mmol/g for Pb²⁺, Cd²⁺, and Ni²⁺, respectively. The order of metal adsorption capacity on peat A was the same in the case of competitive multimetal adsorption conditions as it was for single-element adsorption, namely Pb²⁺ > Cd²⁺ ≥ Ni²⁺. The results show that peat alone (an inexpensive adsorbent) is a good adsorbent for heavy metal ions.     

Effect of depth of landfill on the characteristics of soil-like material of aged waste: a case study of Bhalswa dumpsite,India

Journal of Material Cycles and Waste Management - This study characterizes the municipal solid waste (MSW) accumulated for more than 25 years at Bhalswa dumpsite, Delhi, India. 50...     

袋式除尘器气流分布数值计算研究

采用结构化/非结构化混合网格技术、多孔介质模型及k-ε两方程湍流模型,对某袋式除尘器及进出口管道内的气体流场进行了数值计算.计算结果表明,合理布置导流板后,袋式除尘器两箱体流量偏差为1.8％;除尘器下游滤袋单元处理气量偏大,中游滤袋单元处理气量较小,最大流量与最小流量偏差为22.3％;靠近除尘器进口处灰斗内存在气流回流特性,易造成粉尘的二次附着现象.     

Kinetics of Hydrolytic Degradation of PLA

The chemical recycling of poly(lactic acid) (PLA) to its monomer is crucial to reduce both the consumption of renewable resources for the monomer synthesis and the environmental impact related to its production and disposal. In particular, the production of lactic acid from PLA wastes, rather than from virgin raw materials, it is also possible to achieve considerable primary energy savings. The focus of this work is to analyse deeply the PLA hydrolytic decomposition by means of a kinetic model based on two reactions mechanism. To this end, new experimental data have been gathered in order to investigate a wider temperature range (from 140 to 180 °C) and to extend the water/PLA ratio up to 50 % of PLA by weight. The reported results clearly highlight that more than 95 % of PLA is hydrolyzed to water-soluble lactic acid within 120 min, when it is hydrolyzed within 160–180 °C. Furthermore, the kinetic constant is highly influenced by reaction temperature. The proposed “two reactions” kinetic mechanism complies satisfactorily with the experimental data under analysis.