低浓度SO_2检测管的研制

通过对常见的几种检测管法的比较，筛选出灵敏度较高的亚硝基铁氰化钠法；同时筛选出载体为６０—８０目的素陶瓷，指示剂浓度为２０％。玻璃管内径为２．０—２．３ｍｍ，采气速度为０．３（Ｌ／ｍｉｎ），采样体积为１２Ｌ，以此条件进行实验．结果表明，检测管变色长度对应ＳＯ２浓度的相关性很好；变异系数均小于１１０％，检测的重现性较好。检测管的测定值与理论值的平均相对误差为５．０９％（＜±１５％），最大相对误差为７．１３％（＜±２５％），准确度较高．测定结果可靠；与化学法比较，两者无显著性差异；浓度小于０．１５ｍｇ／ｍ３的Ｈ２Ｓ及浓度小于０．０１ｍｇ／ｍ３的ＮＯ２对ＳＯ２检测管无干扰．     

异相平衡流动注射分光光度法测定水中痕量SO^2—4

根据异相平衡的原理,确立了用流动注射分光光度法测定水样中痕量ＳＯ＾２－４的新方法。利用Ｂａ（Ⅱ）与偶氮氯磷Ⅲ的二元络合显色反应及ＢａＳＯ４＝Ｂａ＾２＋＋ＳＯ＾２－４进入微溶化合物ＢａＳＯ４反应柱前后吸光值的改变,从而求得ＳＯ＾２－浓度。表观摩尔吸光系数ε＝２．３＊１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１,ＳＯ＾２－４检的线性范围为０－４０ｍｇ／Ｌ,检测限为０．８０ｍｇ／Ｌ,相对标准偏差为１．２％,试     

结晶紫褪色分光光度法测定SO_2的研究

在碱性介质中,ＳＯ２能使结晶紫褪色且褪色的程度随ＳＯ２量的增加而呈线性关系,据此建立了分光光度法测定ＳＯ２的新方法,确定了显色测定的最佳条件。方法的最大吸收波长在６００ｎｍ处,表观摩尔吸光系数为７３×１０３Ｌ／ｍｏｌ·ｃｍ。ＳＯ２量在０～１００μｇ／２５ｍｌ范围内符合比尔定律     

光离子化检测器便携式气相色谱仪快速测定空气中苯系物

本文研究了使用光离子化检测器便携式气相色谱仪，直接测定空气中ｍｇ／ｍ３级苯系物（苯、甲苯、乙苯、邻、间、对位的二甲苯及异丙苯）的快速分析方法。方法的线性范围为０～１００ｍｇ／ｍ３，相关系数均在０．９９９以上，方法的变异系数分别为２．９～１２．５％（５ｍｇ／ｍ３），３．４～７．９％（３０ｍｇ／ｍ３），方法最低检测限达０．２～１．０ｍｇ／ｍ３。     

机动车尾气及其扬尘对克拉玛依市环境空气影响特征分析

通过对克拉玛依市机动车尾气及扬尘的实验结果分析,得知城市环境中污染因子ＮＯｘ、ＣＯ、ＴＳＰ等与汽车尾气和扬尘紧密相关,其车流量全天峰期在１１：００－１２：００,ＣＯ、ＮＯｘ峰值达６．００ｍｇ／ｍ＾３和０．１０ｍｇ／ｍ＾３ＴＳＰ浓度达峰值后变化很小。污染物扩散速度与交通干线两侧环境,即垂直距离呈负相关关系。     

纳氏试剂比色法测定氨氮的问题及修正

预蒸馏—纳氏试剂比色法测定污水中氨氮实验中，硼酸与氢氧化钠用量影响有色胶体的稳定和测定的灵敏度，本文研究了影响规律，发现氢氧化钠有增敏作用，提出工作曲线应使用经过校正的标准曲线，校正曲线绘制及水样分析时，采用溶液中Ｈ３ＢＯ３含量为０．４％、ＭａＯＨ含量为０．２ｍｏｌ／Ｌ显色溶液胶体稳定时间长达１２小时以上，线性范围扩展为０～９ｍｇ／ｉ，最低检出浓度为０．０１５ｍｇ／ｌ     

离子色谱法同时测定水中的SeO_3~（2－）和SeO_4~（2－）

用抑制型离子色谱法探讨了ＳｅＯ３（２）和ＳｅＯ４（２－）等七种阴离子的洗脱行为，讨论了共存阴离子的干扰及其消除，建立了测定水中ｓｅＯ３（２－）和ＳｅＯ４（２－）等阴离子的方法．ＳｅＯ３（２－）和ＳｅＯ４（２－）的检测限分别为４０μｇ／Ｌ和５０μｇ／Ｌ．     

单柱离子色谱法同时测定地面水中阴离子

单柱离子色谱法同时测定地面水中Ｆ－、Ｃｌ－、ＮＯ－２－Ｎ、ＮＯ－３－Ｎ、ＳＯ２－４阴离子。以２．５ｍＭ苯二甲酸、２．４ｍＭ三羟甲胺缓冲液为淋洗液,在ｐＨ＝４．０,流速为１．５ｍｌ／ｍｉｎ的条件下,测得各阴离子检出限、线性回归方程及相关系数、方法的精密度和准确度。     

气相色谱法测定空气中三氯乙烯和四氯乙烯

应用气相色谱法以５％ＰＥＧ－６０００为固定液、６２０１为担体填充柱分离，电子捕获检测器检测，直接进样测定环境空气中三氯乙烯和四氯乙烯。对０．０２９ｍｇ／ｍ＾３四氯乙烯标准样作重复５次测定，其相对标准差分别为５．７％和１．５％，并在实际样品中进行加标回收试验，回收率三氯乙烯在９０％～１１０％、四氯乙烯在９４％～１０８％之间。检测限分别为０．００６ｍｇ／ｍ＾３和０．０００５ｍｇ／ｍ＾３，完全能满足环境     

以N,N—二甲基苯胺为偶联试剂示波极谱法测定水中NO2^——N

研究了ＮＯ２＾－－磺胺重氮盐与Ｎ,Ｎ－二甲基苯胺偶联反应的条件及产物在乙醇,ＮＨ３－ＮＨ４Ｃｌ（ｐＨ＝１０）介质中的极谱行为。二阶导数波高与ＮＯ２＾－－Ｎ浓度在０．０００６－０．０７ｍｇ／Ｌ内呈良好线性关系,回收率为９７％－１０２％,已用于环境水中ＮＯ＾－２－Ｎ的测定。     

燃用蔗髓锅炉的硫平衡及二氧化硫排放分析

通过现场监测和调研数据,分析燃用蔗髓锅炉的硫平衡及SO 2排放情况。结果显示,烟气排放的SO 2主要来源于鲜蔗和回用洗布水中含有的硫。8个锅炉硫排放在线监测均值与手工监测均值相对偏差为3.76%~14.9%,表明结果一致性较好。蔗髓硫质量分数为0.01%~0.04%,蔗髓含硫折算后的SO 2值和在线监测SO 2值分别为22.1 mg/m 3~49.9 mg/m 3和43.9 mg/m 3~114.5 mg/m 3,说明鲜蔗和制糖工艺流程的共同影响使得燃用蔗髓锅炉排放烟气SO 2值偏高。     

烟道气中二氧化硫的干扰消除

烟道气中的二氧化硫干扰因素多，不容易测准．本文通过对比实验认为．影响采样精度和分析准确度的干扰因素有：（１）转子流量计的影响；（２）冷凝水对二氧化硫的吸附；（３）氮氧化物对测定的干扰。严格控制上述实验条件，即可得到准确的二氧化硫浓度值。     

Reduction of SO2 Emissions by Ammonia Gas During Staged Combustion

To reduce SO2 emissions, ammonia gas was injected into a coal-fired fluidized-bed combustor under staged commbustion condition. The combustor was 2 m high with a 30 cm static bed height and a freeboard height of 170 cm. The ammonia gas was injected at 52 cm and 65 cm above the distributor, which had a temperature of ca. 700 °C, by an uncooled stainless-steel tube injector. The experiments investigated the effects of ammonia gas injection on sulphur dioxide emissions at staged conditions, varying the: (i) excess air level, (ii) secondary air ratio, (iii) fluidizing velocity, (iv) ammonia injection position, and (v) the ammonia : sulphur dioxide molar ratio.A maximum reduction of 66% in SO2 emissions was found at 40% excess air, 65 : 35 staging, 1.5 m/s fluidizing velocity, 65 cm injection height, and an NH3 : SO2 molar ratio of 1.2. The onset of SO2 reduction occurred at an NH3 : SO2 ratio of 0.5. The fluidizing velocity, excess air, level of staging, and ammonia injection height all have a significant influence on SO2 reduction.It is difficult to determine how the SO2 reduction varies with the operating conditions when ammonia is injected in the high temperature zone of the combustor. As sulphur oxides-ammonia reactions are low temperature reactions, the findings confirm the occurrence of reactions above the freeboard or near the exit to the cyclone.     

Atmospheric aerosol concentration level and chemical characteristics of water-soluble ionic species in wintertime in Beijing,China

Total suspended particulate (TSP) samples were collected during wintertime from November 24, 1998 to February 12, 1999 in Beijing. Ionic species including Cl-, NO3(-), SO4(2-), Na+, NH4(+), K+, Mg2+ and Ca2+ were determined by Ion Chromatography (IC). The sum average concentration of all the determined ions accounted for 18.9% of the TSP concentration, and SO4(2-) appeared the dominant ion with an average concentration of 30.84 microg m(-3); the sum mass concentration of SO4(2-), NO3(-), Ca2+ and NH4(+) accounted for about 83.2% of all the eight ions measured. The study indicated that the chemical form of sulfate and ammonium varies with TSP concentration levels. During heavy pollution periods, the average TSP concentration was 0.66 mg m(-3), and the NH4(+)/SO4(2-) molar ratio was low (0.58). It indicated that sulfate may present as CaSO4 and (NH4)2SO4 x CaSO4 x 2H2O. When TSP concentration (average 0.186 mg m(-3)) was relatively low, the NH4(+)/SO4(2-) molar ratio was 1.94, close to the theoretical ratio of 2 of (NH4)2SO4. Under this condition (NH4)2SO4 is expected to exist as the major form of sulfate. When the TSP concentration level was medium (average 0.35 mg m(-3)), the NH4+/SO4(2-) molar ratio appeared an average value (1.27), (NH4)2SO4, (NH4)2SO4 x CaSO4 x 2H2O and CaSO4 are expected to be present in those aerosol particles. Meteorological conditions including wind speed and wind direction were related to the TSP concentration level.     

Continuous monitoring of NO in flue gas based on wavelet decomposition

In this paper, a new algorithm for nitric oxide (NO) measurement based on multi-scale wavelet decomposition is proposed. The algorithm uses one-dimensional discrete multi-scale wavelet decomposition to analyze the transmission spectrum of flue gas. Through the different scales of decomposition, the relation between the absorption characteristics of NO gas and the reconstruction of wavelet coefficients is found. The DB9 wavelet can obtain the most obvious absorption characteristics of the NO gas. After calibration, the algorithm is used to measure the concentration of the mixture of NO and SO(2). The results show that the algorithm is efficient towards SO(2) absorption interference with a full-scale error less than ± 0.4% in laboratory conditions. The algorithm was then applied to field measurements with an overall standard deviation of 8.37 mg m(-3), which is better than 18.92 mg m(-3) determined by the least squares method. Under the interference of desulfurization, the full-scale measurement errors are less than ± 2%. In addition, the algorithm avoids using the reference spectrum, thereby reducing the aging of the light source effectively. It has strong anti-interference capability, good durability, and practicality in the continuous monitoring of NO.     

乌鲁木齐市大气硫酸盐化速率与二氧化硫浓度的相关性

对全市１９８９年至１９９１年中大气硫酸盐化速率与二氧化硫的监测数据进行了相关性研究，结果表明：除七道湾化工厂外，两项目间存在着非常显著的正相关关系．对建成区７个测点三年中８３对监测数据进行了一无线性回归分析，建立了合理可行的回归方程式     

Combined Non-Catalytic Reduction of NOx and SO2 by Ammonia Liquor during Staged Fluidized-Bed Combustion

Emissions of NOx and SO2 were monitored in the presence of ammonia liquor in a 0.09 m2 and 2 m high stainless-steel fluidized-bed combustor. Experiments were carried out at 2 m/s fluidizing velocity, 40% excess air, and 870 °C bed temperature. Ammonia liquor with 7% ammonia by weight was injected into the freeboard of the combustor 52 cm above the distributor through a water-cooled injector. A 65 : 34 primary/secondary air ratio was maintained throughout the investigation. Approximately 70% of NO and 20% of SO2 was reduced at an NH3/NO molar ratio of 2 : 1, respectively. However, a higher reduction in SO2 emissions (62%) was achieved at a very high NH3/NO molar ratio of 7 : 1. These experiments showed that ammonia addition did have a significant effect in SO2 reduction if injected in an excess amount. The injection of ammonia liquor combined with staged combustion was found to be very effective in reducing NOx emissions. A reduction of about 50% was achieved at an NH3/NO molar ratio of 0.6 : 1 which is also coupled with a very low level of ammonia in the flue.     

Characterization and optimization of an online system for the simultaneous measurement of atmospheric water-soluble constituents in the gas and particle phases

In this work we present the results of extensive characterization and optimization of the Ambient Ion Monitor-Ion Chromatograph (AIM-IC) system, an instrument developed by URG Corp. and Dionex Inc. for simultaneous hourly measurements of the water-soluble chemical composition of atmospheric fine particulate matter (PM(2.5)) and associated precursor gases. The sampling assembly of the AIM-IC consists of an inertial particle size-selection assembly, a parallel-plate wet denuder (PPWD) for the collection of soluble gases, and a particle supersaturation chamber (PSSC) for collection of particles, in series. The analytical assembly of the AIM-IC consists of anion and cation IC units. The system detection limits were determined to be 41 ppt, 5 ppt, and 65 ppt for gas phase NH(3(g)), SO(2(g)), and HNO(3(g)) and 29 ng m(-3), 3 ng m(-3), and 45 ng m(-3) for particle phase NH(4)(+), SO(4)(2-), and NO(3)(-) respectively. From external trace gas calibrations with permeation sources, we determined that the AIM-IC is biased low for NH(3(g)) (11%), SO(2(g)) (19%), and HNO(3(g)) (12%). The collection efficiency of SO(2(g)) was found to strongly depend on the composition of the denuder solution and was found to be the most quantitative with 5 mM H(2)O(2) solution for mixing ratios as high as 107 ppb. Using a cellulose membrane in the PPWD, the system responded to changes in SO(2(g)) and HNO(3(g)) within an hour, however for NH(3(g)), the timescale can be closer to 20 h. With a nylon membrane, the instrument response time for NH(3(g)) was significantly improved, becoming comparable to the responses for SO(2(g)) and HNO(3(g)). Performance of the AIM-IC for collection and analysis of PM(2.5) was evaluated by generating known number concentrations of ammonium sulfate and ammonium nitrate particles (with an aerodynamic diameter of 300 nm) under laboratory conditions and by comparing AIM-IC measurements to measurements from a collocated Aerosol Mass Spectrometer (AMS) during a field-sampling campaign. On average, the AIM-IC and AMS measurements agreed well and captured rapid ambient concentration changes at the same time. In this work we also present a novel inlet configuration and plumbing for the AIM-IC which minimizes sampling inlet losses, reduces peak smearing due to sample carryover, and allows for tower-height sampling from the base of a research tower.