流化床O2/CO2燃烧技术和化学链燃烧技术

O2／CO2燃烧技术不仅能使分离收集CO2和处理SO2容易进行，还能减少NOx排放，是一种能够综合控制燃煤污染物排放的新型洁净燃烧技术。流化床O2／CO2燃烧技术将流化床和O2／CO2燃烧技术的优点结合起来，有可能取得更好的效果。化学链燃烧技术打破了自古以来的火焰燃烧概念，开拓了根除燃料型NOx生成、控制热力型NOx产生与回收CO2的新途径，是解决能源与环境问题的创新性突破口。介绍了流化床O2／CO2燃烧技术和流化床化学链燃烧技术的原理和研究现状，比较了它们之间的差别，展望了发展前景。     

锅炉低NOx排放改造及试验结果分析

介绍了某电厂利用空气分级燃烧技术对420t／h锅炉燃烧器进行的低NOx排放改造情况，对锅炉改造前、后的NOx排放浓度进行了对比分析。结果表明，对锅炉实施低NOx改造后，NOx排放浓度明显下降，但锅炉热效率亦有所降低。     

固态排渣煤粉炉NOx产生浓度影响因素偏相关分析

利用第一次全国污染源普查“火力发电行业产排污系数核算”工作中现场监测得到的数据，首次采用偏相关分析的方法，对固态排渣煤粉炉中机组规模、空气过剩系数、煤中挥发分和发电负荷率等因素对NOx产生浓度的影响进行定性分析，结论：NOx产生浓度与前三种因素存在显著的相关。而与发电负荷率的关系受锅炉是否采用低氮燃烧技术的影响。空气过剩系数越大，煤的挥发分越高，NOx产生浓度越低；采用低氮燃烧装置的锅炉中，机组规模越大，产生的NOx越少，且对于同一锅炉来说，NOx产生浓度随着发电负荷率的升高而增大；未采用燃烧控制的锅炉中，机组规模越大，NOx产生浓度越高，且与发电负荷率不相关。根据分析结果，提出了控制燃煤电厂固态排渣煤粉炉NOx排放的优化措施和建议。     

火电厂降低NOx排放的技术研究

NOx是燃煤电厂烟气排放三大有害物（SO2、NOx及悬浮颗粒物TSP）之一。从污染角度考虑的氮氧化物主要是NO和NO2,统称为NOx。介绍了NOx的生成机理,即热力型NOx和燃料型NOx,前者由参与燃烧的空气中所含的N2生成,后者由燃料本身的氮元素生成。分析了低氮燃烧技术、SCR烟气脱硝技术、SNCR烟气脱硝技术及SCR＋SNCR组合式等NOx控制技术。其中,在燃烧过程中降低NOx生成的主要手段是采用分级燃烧,降低燃烧区域的氧浓度和降低火焰温度;在燃烧后可采用烟气处理技术降低烟气中的NOx含量。     

美国1990洁净空气法修正案要点及火电厂脱硫技术发展趋势

1美国1990洁净空气法修正案1971年美国实施洁净空气怯（以下简称CAA）规定73MW以上的新建电厂锅炉SO2排放浓度不得超过1238mg／Nm3（1．21b／MBtu）。1971年第一次修改法规，规定了SO2排放浓度和脱硫率（见表1）。表11971年修正案的SO2排放浓度和脱硫率自1971年至1991年，美国的环境质量得到了改善，其中粉尘排放量降低61％，CO降低5％，SO2降低27％，NOx降低1％，但是严重的污染问题依然存在，酸雨仍然没有得到控制．1990年11月15日颁布了洁净空气法修正案（（：／‘AA199O）。新修正案的主要指标是：。大气有害污染物至少降低巧…     

W火焰炉低氮燃烧改造可行性研究

对黔北电厂1～4号W火焰锅炉实际运行状态进行分析，得出NO。排放浓度偏高的主要原因，并提出1—4号机组W火焰炉低氮改造的方案，即在拱下燃烧室内组织大回流长火焰燃烧方式，并通过SOFA风形成炉内深度空气分级低氮燃烧。同时针对1、2号炉和3、4号炉各自特性提出具体的改造方案，保证在锅炉效率不降低的条件下，1～4号W火焰锅炉的NOx排放浓度不高于850mg／m3，从而为W火焰锅炉低氮燃烧改造提供可行性方案，保证W火焰锅炉下一步烟气脱硝的顺利进行。     

1025t/h煤粉炉燃烧方式对NOx排放影响的试验研究

介绍了煤粉燃烧过程中NOx产生的机理和火力发电厂降低NOx排放的主要控制技术，并对某1025t／h四角切圆锅炉燃烧方式对NOx排放的影响进行了考察，提出了降低NOx排放的合理运行方式。     

燃烧过程NOx的控制技术与原理

简述了燃烧过程中NO2的生成途径、NO2生成与排放的影响因素，介绍了电站锅炉常用的空气分级燃烧、燃料分级燃烧及烟气再循环三种主要的低氮燃烧技术原理，分析了提高NO2控制效果的主要因素，讨论了提高NO2降低率的技术参数的最佳范围。     

降低循环流化床锅炉污染物排放的措施

对循环流化床锅炉运行影响NOx和SO2生成的主要因素进行了分析,并提出了降低NOxSO2排放量的具体措施。     

W型无烟煤锅炉氮氧化物排放浓度高的原因分析及解决实例

针对燃煤电厂W型火焰无烟煤锅炉普遍存在的NOx排放浓度高的问题进行了原因分析,与一般燃煤锅炉所排NOx以燃料型为主不同,该锅炉所排NOx的主要类型为热力型,炉膛燃烧温度高是热力型NOx产生量高的主要原因.通过对案例电厂煤质及炉型的分析找到了降低NOx排放的可行方法,对锅炉进行简单改造,掺烧烟煤可显著降低锅炉NOx产生量,通过试验确定掺烧烟煤的合适比例,为类似炉型提供参考.     

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.     

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。     

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.     

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.     

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.     

Effect of Degree of Substitution of Octenyl Succinate Starch on Enzymatic Degradation

Octenyl succinate starch of degree of substitution (ds) 0.03, 0.07, and 0.11 was synthesized in an aqueous medium. These compounds were then tested for the susceptibility to enzymatic degradation. The multiple-enzyme regime of -amylase, amyloglucosidase, and pullulanase was chosen for the evaluation. This combination of enzymes had been proven to degrade 99.5% of unmodified starch to glucose and hence was chosen for this study. It was found that even small amounts of subsituent caused a considerable decrease in the extent of degradation. The net extent of degradation decreased with increasing ds. Surprisingly, the amount of glucose from all three substituted substrates was quite similar, suggesting the effect small amounts of subtituent had on the enzymatic activity.     

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.     

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.