气相色谱法测定空气中的1，2-二氯乙烷

建立了一种用气相色谱法测定空气中1，2-二氯乙烷的方法。空气中1，2-二氯乙烷用活性炭吸附，二硫化碳解析，直接进样分析。其回收率为97．6％～100．8％，最低检出浓度为0．005mg／m^3，相对标准偏差为0．7％-2．4％；该方法具有前处理简单、速度快、干扰少、灵敏度高等特点，可用于空气中1，2-二氯乙烷的测定。     

活性炭纤维吸附含溴甲烷气体的性能

采用动态吸附法在25℃下,测定了3种活性炭纤维(ACF-1、ACF-2和ACF-3)对含溴甲烷气体的吸附性能和回收效果,并对活性炭纤维的孔结构进行表征.探讨了孔结构、溴甲烷浓度、气体流量、循环使用次数等因素对活性炭纤维吸附溴甲烷性能的影响.结果表明,活性炭纤维比表面积大小及0.4～0.8 nm左右的微孔数量决定了其对溴甲烷吸附性能的优劣;气体中溴甲烷的浓度的提高使活性炭纤维对溴甲烷的穿透和饱和吸附量增加,而气体流量的增加则使活性炭纤维对溴甲烷的穿透和饱和吸附量降低,但两者均使穿透和饱和吸附时间缩短;活性炭纤维多次循环使用后,对溴甲烷的吸附容量明显地降低,循环12次后达到稳定吸附,其稳定吸附值为133.5 mg/g.     

空气与废气中的正丁烷、丁酮、醋酸异丙酯的快速测定法

采用活性炭吸附，二硫化碳解析，毛细管气相色谱法同时测定空气与废气中的正丁烷、丁酮、醋酸异丙酯，采样体积以45L计，方法最低检出限分别为：正丁烷0．002mg／m^3，丁酮0.0024mg／m^3，醋酸异丙酯0．0028mg／m^3。     

毛细管柱气相色谱法测定空气中的乙酸乙酯

用二硫化碳解析活性炭管中的乙酸乙脂，用毛细管柱气相色谱法测定，相关系数为0.9983，检出量9ng，回收率大于90％，方法简单、快速，准确，灵敏度高。     

基于Г型分布的空气质量评价普适指数公式

在设定各项空气污染物的浓度“参照值”基础上，提出了一个适用于多项空气污染物的Г型分布空气质量评价普适指数公式。采用基于实数编码的遗传算法对公式中的参数优化，得出优化后适用于多项空气污染物的空气质量评价普适指数公式。公式被应用于多个实例分析计算，并与其他若干评价方法评价结果相比较，结果表明，该公式不受空气污染物种类和数目多少的限制。公式形式简单，计算快速，具有可比性、通用性和实用性。     

空气微生物研究方法进展与展望

着重论述了空气微生物气溶胶的研究方法，主要有培养基法和非培养基法。培养基法是传统的微生物研究方法，需要花费大量的时间和劳动力，只能够检测活的能够在培养基上生长的微生物，可以大致反映空气中的微生物气溶胶。非培养基法，主要是PCR法，具有敏感性高、快速、特异性强等特点，能够检测出环境样品中绝大多数的微生物，是一种微生物气溶胶检测的有效途径。最后指出实时持续的监测是将来空气微生物研究的努力方向和发展趋势。     

热解析-固相微萃取-气相色谱法测定空气样品中挥发性有机化合物

建立了热解析-固相微萃取-气相色谱法测定空气样品中挥发性有机化合物的分析方法，并对色谱分离条件、玻璃针筒保存样品的稳定性、固相微萃取萃取纤维、萃取时间、色谱进样时间等条件进行了优化，9种挥发性有机化合物的峰面积与其质量浓度在所测范围内有较好的线性关系，相对标准偏差＜8.8%，检出限为0.05～0.75 μg/100 mL，满足实际空气样品测定需要。     

裸土风蚀型开放源起尘对城市空气颗粒物的影响评估

多个城市的空气颗粒物源解析结果表明,开放源是北方城市空气颗粒物的最主要贡献者,是影响空气颗粒物达标的重要源类,其中裸土风蚀尘是空气颗粒物最主要来源。以天津市为例,利用箱模型和源解析模型测算了天津市裸土风蚀型开放源的起尘量及其对城市空气颗粒物的贡献值。计算结果表明,裸土风蚀型开放源总悬浮颗粒物(TSP)的起尘量为13.18×104t/a,平均贡献值为103.53μg/m3,PM10的起尘量为5.28×104t/a,平均贡献值为41.45μg/m3。表明裸土风蚀的起尘量对环境空气质量的影响绝不能低估,应该重视裸土风蚀型开放源的污染控制。     

裸土风蚀型开放源起尘机制研究进展

中国北方多个城市空气颗粒物来源解析结果表明,开放源是空气颗粒物污染的主要来源,裸土风蚀型开放源是主要的排放源类.对裸土风蚀型开放源起尘机制进行了诠释,提出了裸土风蚀型开放源、裸土风蚀起尘、裸土风蚀尘的概念,并对裸土风蚀型开放源的风蚀影响因素进行了研究,为城市空气质量达标及空气颗粒物污染防治提供科学参考.     

杭州市空气颗粒物污染特征及变化规律研究

根据2006—2010年杭州市空气颗粒物的监测数据及2002、2006、2008年空气颗粒物来源解析结果,对杭州市空气颗粒物浓度、化学组分与污染来源等特征的变化规律进行分析,以期为空气颗粒物污染控制提供决策依据。结果表明,近年来杭州市PM10浓度有所下降,但一类功能区PM10仍超出《环境空气质量标准》(GB 3095—1996)的要求(≤0.04mg/m3),杭州市空气颗粒物污染以细颗粒物为主,空气颗粒物的二次转化、机动车尾气尘等产生的二次粒子污染相对严重;煤烟尘对杭州市PM10的贡献率下降明显,城市扬尘、二次粒子和机动车尾气尘对PM10的贡献率有所增加,是杭州市PM10的主要来源。     

Sulfur Gas Emissions From Stored Flue Gas Desulfurization Sludges

The emissions of volatile sulfur-containing compounds from 13 flue gas desulfurization (FGD) sludge field storage sites have been characterized. Sulfur gas emissions from the sludge surfaces were determined by measuring the sulfur gas enhancement of sulfur-free sweep air passing through a dynamic emission flux chamber placed over selected sampling sites. Samples of the enclosure sweep air were cryogenically concentrated in surface-deactivated Pyrex “U” traps. Analyses were conducted by wall-coated, open-tubular, capillary column, cyrogenic gas chromatography using a sulfur-selective, flame photometric detector. Several major variables associated with FGD sludge production processes were examined in relation to the measured range and variations in sulfur fluxes including: (a) the sulfur dioxide scrubbing reagent used, (b) sludge sulfite oxidation, (c) “unfixed” or “fixed” FGD sludge, and (d) ponding or landfill storage. The composition and concentration of the measured sulfur gas emissions were found to vary with the type of sludge, the effectiveness of rainwater drainage from the landfill surface, the method of impoundment, and the sulfate/sulfite ratio of the sludge. Hydrogen sulfide, carbonyl sulfide, dimethyl sulfide, carbon disulfide, and dimethyl disulfide were identified in varying concentrations and ratios in the FGD sludge emissions. In addition, up to four unidentified organo- sulfur compounds were found in the emissions from four FGD sludges. The sulfur flux from one FGD storage pond was analyzed by gas chromatography-single ion monitoring mass spectrometry. In addition to the four identified sulfur compounds, this flux contained large concentrations of benzene, toluene, and α-pinene. The measured, total sulfur emissions ranged from less than 0.01 to nearly 0.3 kg of sulfur per day for an equivalent 100 acre (40.5 hectare) sludge impoundment surface.     

Sulfur Gas Emissions from Flue Gas Desulfurization Sludge Ponds

This paper presents initial measurement data on the emission of volatile, reduced sulfur-containing gases from flue gas desulfurization (FGD) storage ponds. Several different types of FGD stored sludges were studied including lime, limestone, and mixtures of fly ash and lime or limestone residues, some of which had been chemically stabilized. The volatile sulfur gas emissions were cryogenically concentrated and determined by wall-coated, open-tubular capillary column gas chromatography using a flame photometric detector. Hydrogen sulfide, carbonyl sulfide, dimethyl sulfide, carbon disulfide, and an unusual, unidentified sulfur-containing compound were found in the gaseous pond flux. Benzene, toluene, and α-pinene were also identified by gas chromatography-single ion monitoring mass spectrometry. The total reduced sulfur gas emission from a 100 acre pond approximated 2.0 kg day^?1 (as sulfur).     

Precipitator Gas Flow Distribution

An electrostatic precipitator, furnished on a 500-Mw tan-gentially-fired steam generator burning coal, was to collect 99.6% of the fly ash being generated in the furnace of this unit. Preliminary measurements indicated that the installation was not meeting its collection guarantee. Precipitator outlet flue dust distribution indicated that poor gas flow distribution might be one of the causes of the low performance. When observation ports were installed in the outlet flue to permit a direct visual evaluation of the problem, it was found that high velocity jets were present in the collecting electrodes, and that hopper sweepage was present. A model study along with velocity distribution measurements of the installation were authorized. Flow analysis indicated that the field and model correlated well. Extensive changes were made in the model, which eliminated or minimized the high velocity jets and hopper sweepage. After these changes were made in the field installation, it was able to achieve the required dust collection efficiency.     

Gas phase naphthalene chlorination

Chlorination of naphthalene by Cl atoms has been studied in the gas phase. The chlorinating agent was produced by γ-radiolysis of tetrachloromethane. At low conversions only monosubstituted products are observed. Both isomers are formed, the yield of 1-chloronaphthalene exceeding that one of its isomer. The extent of the addition reaction increases with the temperature. The relative Arrhenius plot of observed rate constants is linear over the temperature range investigated (60–120 °C) and its slope corresponds to a difference of 11.0 kJ/mol between the activation energies of 2-chloronaphthalene and 1-chloronaphthalene.     

Feasibility of Landfill Gas as a Liquefied Natural Gas Fuel Source for Refuse Trucks

Abstract

The purpose of this paper is to develop a methodology to evaluate the feasibility of using landfill gas (LFG) as a liquefied natural gas (LNG) fuel source for heavy-duty refuse trucks operating on landfills. Using LFG as a vehicle fuel can make the landfills more self-sustaining, reduce their dependence on fossil fuels, and reduce emissions and greenhouse gases. Acrion Technologies Inc. in association with Mack Trucks Inc. developed a technology to generate LNG from LFG using the CO₂ WASH process. A successful application of this process was performed at the Eco Complex in Burlington County, PA. During this application two LNG refuse trucks were operated for 600 hr each using LNG produced from gases from the landfill. The methodology developed in this paper can evaluate the feasibility of three LFG options: doing nothing, electricity generation, and producing LNG to fuel refuse trucks. The methodology involved the modeling of several components: LFG generation, energy recovery processes, fleet operations, economic feasibility, and decision-making. The economic feasibility considers factors such as capital, maintenance, operational, and fuel costs, emissions and tax benefits, and the sale of products such as surplus LNG and food-grade carbon dioxide (CO₂).

Texas was used as a case study. The 96 landfills in Texas were prioritized and 17 landfills were identified that showed potential for converting LFG to LNG for use as a refuse truck fuel. The methodology was applied to a pilot landfill in El Paso, TX. The analysis showed that converting LFG to LNG to fuel refuse trucks proved to be the most feasible option and that the methodology can be applied for any landfill that considers this option.     

Quantitation of Stack Gas Flow

The presently available standards for measurement of gas flow in stacks and industrial flues are reviewed. Various problems associated with probe traverse techniques using the pitot-static tube, the Type S pitot tube, a directional type pitot tube, and hot wire anemometers are described. Recommendations are made with respect to the selection of velocity measurement station, and the selective application of velocity measurement devices is discussed.     

Gas Dilution Apparatus for Preparing Reproducible Dynamic Gas Mixtures in any Desired Concentration and Complexity

A portable gas dilution apparatus has been constructed by which reproducible known mixtures of the common air pollutants added to carbon filtered air can be prepared in any desired quantity, complexity, and concentration. Sulfur dioxide mixtures with and without the addition of nitrogen dioxide and/or ozone have been analyzed by the conductimetric, titrimetric, turbidimetric, and colorimetric methods. Excellent analytical agreement with the concentrations obtained from the volumes of sulfur dioxide, nitrogen dioxide, hydrogen sulflde, and air that are mixed has been shown by all these methods when an efficient absorber is used though the titrimetric method tended to give slightly low results. Some common absorbers show reduced efficiency in absorbing some of the gases. Nitrogen dioxide determinations by the Saltzman method are not significantly affected by the addition of sulfur dioxide to the nitrogen dioxide-air mixtures. A modification of the Saltzman reagent, due to Lyshkow, was tested. It accelerates the rate of color development and should be useful in the automatic nitrogen dioxide analyzer. The determination of hydrogen sulfide is not affected by the presence of nitrogen dioxide in the gas mixture but sulfur dioxide increases the sulfide reading by about 5-15% while ozone decreases the reading.     

废气生物净化技术研究进展

废气生物净化技术是近年来发展起来的大气污染控制新技术，文章介绍了国内外这方面的历史及现状、主要处理工艺设备，概述了目前所进行的微生物学及反应动力学方面的研究，同时指出了今后的研究方向。     

Gas Chromatographic Analysis of Incinerator Effluents

Comparative gas cleaning performance of a pilot-scale venturi scrubber with throat dimensions of 6 in. wide × 1 2 in. long × 1 2 in. deep was obtained for the following three methods of water injection: a system of spray nozzles located along each short side of the throat (Figure 2a); a continuous slot located immediately above the nozzles, along each short side of the throat (Figure 2b); and a weir located 2 ft above the spray nozzles along long side of the throat (Figure 2c). For each method of water injection the gas cleaning performance, as a function of the pressure drop, was measured by two tests: absorption of SO₂ and collection efficiency for particles of methylene blue of controlled size.