某厂金属铜管加工废气处理方法的研究

我国对于大气污染物的排放给予了高度的重视,规定生产中的污染物必须达标排放。对某厂酸洗车间产生的以酸雾和氮氧化物为主的废气采用高效局部排气罩加以集中收集,设计了净化吸收系统,使经过处理的废气达到“大气污染物综合排放标准”中的二级排放要求,并在设计中充分考虑了系统的节能,收到了良好的环保效果。     

生物滴滤器净化低浓度甲苯废气的非稳态工况研究

生物法处理大气污染物时，经常会遇到条件波动或污染物间歇排放等非稳态工况。在不同非稳态条件下，考察了甲苯废气间歇排放对生物滴滤器净化性能的影响。实验方案分3种情况：无甲苯废气排放、无循环液供应或同时没有甲苯废气和循环液的供应。间歇排放时间从2-47d不等。结果表明，不管何种形式的停运或故障，甲苯净化能力4d以内基本不下降；停运时间超过5d，则甲苯去除能力严重下降，仅为原来的1／3-1／2；停运时间在10d以内，24h内即可恢复，47d的长期停运，3d内也可恢复净化能力。     

美国的废气连续监测技术

随着对工厂大气污染物排放总量的限制越来越严,在美国,废气连续监测(CEM)系统已成为工艺设施和工厂运行中不可分割的一部分.1990年通过的“清洁空气法修正案(CAAA)”明确要求锅炉设施必须安装CEM系统,进行流量监测,以便能准确、可靠地对SO_2、NO_x、Co_2等污染物的排放量和能见度进行测量.下面就美国的废气连续监测技术作一简单介绍.1监测系统的分类连续监测系统分为现场连续监测和取样连续监测两类;后者又可进一步分为全样连续监测(湿样分析或干样分析)和稀释样连续监测.但无论采用何种方法,准确性都必须大于90%由于CEM系统只能测出污染物的体积比浓度(PPm),而排放标准中要求的是单位时间内排放污染物的质量,所以,还必须进行流     

生物过滤塔处理实验室废气

研究了生物过滤塔处理实验室排放的模拟混合废气,考察了反应器对苯、甲苯、二甲苯、乙醇、丙酮、乙酸乙酯和甲烷等废气的去除效果。运行结果表明,在设备稳定运行期间,进气中总挥发性有机物(TVOCs)的浓度为124～380 mg/m3,而出气浓度在10～40 mg/m3,去除效率保持在85%以上。实验室废气中的多种污染物在生物过滤塔中去除机理不同,亲水性污染物的去除效率高于疏水性污染物。通过系统关停后重启,污染物的去除效果在第2天就能恢复,这为生物过滤塔处理实验室废气过程的停运检修或者系统闲置提供了可行性。     

燃煤锅炉烟囱高度复核计算方法应用实例分析

主要结合地区大气污染状况，气象条件，污染物排放参数及环境控制目标等因素，运用大气环境影响评价中大气扩散有关模式及理论，通过实例分析对燃煤锅炉烟囱设计高度进行复核计算，使锅炉排放污染物满足地区环境控制目标需要。     

生物滴滤器净化低浓度甲苯废气的非稳态工况研究

生物法处理大气污染物时,经常会遇到条件波动或污染物间歇排放等非稳态工况。在不同非稳态条件下,考察了甲苯废气间歇排放对生物滴滤器净化性能的影响。实验方案分3种情况:无甲苯废气排放、无循环液供应或同时没有甲苯废气和循环液的供应。间歇排放时间从2~47 d不等。结果表明,不管何种形式的停运或故障,甲苯净化能力4 d以内基本不下降;停运时间超过5 d,则甲苯去除能力严重下降,仅为原来的1/3~1/2;停运时间在10 d以内,24 h内即可恢复,47 d的长期停运,3 d内也可恢复净化能力。     

XLC—1001型稀土尾气催化剂

内燃机排出的废气,在大气的污染物中占很大比重,世界上现有二亿多辆汽车,每年排出的有害气体:CO二亿吨,碳氢化合物四百万吨,氮氧化物二千万吨。为防止公害,国外对内燃机废气净化技术做了大量的研究工作,制定了废气排放标准,并有催化剂公司生产、销售铂系催化剂,供内燃机尾气净化用。 国外使用的尾气净化催化剂,以贵金属铂催化剂为主,因为它的活性高,使用     

上海市机动车尾气VOCs组成及其化学反应活性

采用钢罐采样-气相色谱/质谱法,采集并分析了上海市主要交通干道和隧道废气样品中挥发性有机物(VOCs)的污染水平。分析结果表明,交通干道和隧道废气样品的总挥发性有机污染物(TVOC)质量浓度分别为(227.1±40.9)、(2209.9±1228.0)μg/m3;隧道废气样品中的TVOC浓度是交通干道平均浓度的4.3～15.2倍;交通干道废气样品中VOCs主要组分与隧道废气样品中VOCs主要组分非常类似,说明交通干道废气样品中VOCs主要来源于机动车尾气排放。交通干道废气样品中TVOC的.OH消耗速率为(17.21±4.49)s-1,延安东路隧道和打浦路隧道废气样品中TVOC的.OH消耗速率分别为(300.37±120.78)、(138.09±25.30)s-1,烯烃对TVOC的.OH消耗速率贡献最大,其对废气化学反应活性贡献率在70%以上。交通干道和隧道废气样品中关键活性组分是C2～C5的烯烃组分,这些组分也是机动车尾气中的特征污染物,因此可以判断机动车尾气是上海市大气化学反应活性的最大贡献者。     

小型燃油锅炉大气污染物的排放管理控制

燃料燃烧过程是大气污染物的重要来源之一,对人体健康,空气质量和气候变化具有非常重要的影响;管理控制是控制污染物排放的重要手段.以85台小型燃油锅炉(≤10.5 MW)燃料特性分析数据和污染物排放实测数据为基础,通过统计分析方法,分析了中国在用燃油品质以及大气污染物的排放现状,讨论了小型燃油锅炉大气污染物排放管理控制的潜力与可行性.结果表明,对燃油品质的管理控制是有效控制燃烧过程大气污染物排放的重要措施,分别有95%和98%燃油的灰分和含硫量符合国家相关规定;所有测试锅炉PM排放浓度远低于<锅炉大气污染物排放标准>(GB/T 13271-2001)规定的最高允许排放限值,有90%以上的锅炉达到GB/T 13271～2001中SO2最高允许排放限值,有84%的锅炉达到GB/T 13271-2001中NOx最高允许排放限值;与其他国家相比,中国对小型燃油锅炉常规大气污染物排放的管理控制处于中等水平,应当适时开展对有害空气污染物的管理控制.     

火电厂大气污染物排放预测模型

根据大气污染物排放浓度变化特点,将无偏GM(1,1)模型与神经网络模型组合,并以矩阵型输入方式替代传统的数列型数据输入方式,得到改进型灰色神经网络模型,称为UGMN模型。接着,采用烟囱入口烟气自动监控系统(CEMS)数据,将模型运用于贵州省某电厂白天及夜间两段时间段内大气污染物排放浓度的模拟与预测。研究结果表明UGMN模型预测精度较好,可以应用于火电厂大气污染物排放浓度预测。     

Emission of specific pollutants from a compression ignition engine. Influence of fuel hydrotreatment and fuel/air equivalence ratio

A compression ignition engine is used for the study of the fuel (one reference and one hydrotreated) and the fuel/air equivalence ratio influence on the exhaust emissions of specific pollutants. Under the experimental conditions used, seven hydrocarbons, nine aldehydes and three organic acids are detected in the exhaust gas. No alcohols are detected under these conditions, indicating that these compounds are emitted only if they (or probably other oxygenated compounds) are introduced in the fuel. Fuel hydrotreatment decreases most of the exhaust pollutants, the four toxics and also the quantity of the ozone that could be formed from the exhaust gas. It also changes the composition of exhaust gas: it increases the proportion of methane, benzene, formaldehyde, acetaldehyde, acroleine, and propionic acid, while it decreases the proportion of all other pollutants detected. Fuel/air equivalence ratio also decreases most of the exhaust emissions, the emission of the total toxics and the quantity of the ozone that could be formed. It also changes the proportion of each pollutant in exhaust gas: the percentages of methane, benzene, acetone and acetic acid increase, while those of the other pollutants detected decrease. The majority of the specific pollutants detected corresponds to organic acids, followed by hydrocarbons and aldehydes.     

Responses of spruce seedlings (Picea abies) to exhaust gas under laboratory conditions--I. Plant-insect interactions

The effects of motor vehicle exhaust gas on Norway spruce seedlings (Picea abies (L.) Karst) and plant-insect interaction of spruce shoot aphid (Cinara pilicornis Hartig) was studied. The exhaust gas concentrations in the fumigation chambers were monitored and controlled by measuring the concentration of nitrogen oxides (NO(x)) with a computer aided feedback system. The concentrations of major exhaust gas components (black carbon [BC], fine particles, VOCs and carbonyl compounds) in the chamber air were also measured. Responses of Norway spruce seedlings to a 2 and 3-week exhaust gas exposure and subsequent performance of spruce shoot aphid were studied using realistic exposure regimes; 50, 100 and 200 ppb NO(x). The feedback control system based on NO(x) concentrations proved an adequate and practical means for controlling the concentration of exhaust gases and studying plant responses in controlled environment chambers. The exhaust exposure resulted in increased concentrations of proline, glutamine, threonine, aspartic acid, glycine and phenylalanine and decreased concentration of arginine, serine, alanine and glycine in young needles. No changes in soluble N concentrations were observed. The results are interpreted as a stress response rather than use of NO(x) as a nitrogen source. No changes in total phenolics and only transient changes in some individual terpene concentrations were detected. The exhaust gas exposure stressed the exposed seedlings, but had no significant effect on N metabolism or the production of defence chemicals. Aphid performance was not significantly affected. Soluble N, secondary metabolism and aphid performance were not sensitive to exhaust gas exposure during shoot elongation in Norway spruce.     

重庆市机动车尾气对大气环境的影响分析及减缓措施

在对重庆市机动车保有量、主城区交通状况进行深入调查的基础上，对机动车尾气排放对大气环境的影响进行了细致的分析与评估。阐述了机动车尾气是造成重庆市大气污染的重要因素。同时结合国内外一些先进的预防、控制和处理汽车尾气污染的方法，及近年来的观察、研究和试验，提出了合理减缓、控制机动车尾气污染的措施，以防止机动车尾气污染进一步蔓延。     

Comparison of EGR ratios determined by four different methods for electronic re-circulation gate control

In this study, low pressure systems have been applied for exhaust gas recycling (EGR), which is applied in certain operating conditions. Induction air, exhaust gas flow, amount of exhaust gas added to the induction air, amount of carbon dioxide (CO₂) in the exhaust gas, and amount of carbon dioxide in the induction air mixed with the exhaust gas, have been measured and the EGR ratio has been determined using four different calculation methods. The obtained results have been compared, and it has been noted that all the four methods have given similar results, and the deviation among them has been noted to be 1% at most. Deviations among the results have been explained. In the concluding section, a relation has been formed between the variables chosen as basic parameters, electronic re-circulation gate control, and variables utilised in EGR ratio determination methods.     

Responses of spruce seedlings (Picea abies) to exhaust gas under laboratory conditions--II. Ultrastructural changes and stomatal behaviour

This study examines the effects of exhaust gas exposure on the epistomatal wax structure and mesophyll ultrastructure in needles of Norway spruce (Picea abies (L.) Karst.) seedlings. Stomatal diffusive resistance was also measured. Two independent exhaust gas fumigations were performed: 100 and 200 ppb measured as NO(x), for 10 days and 50, 100 and 200 ppb NO(x) for 19 days. The obstructive effect of exhaust gas exposure on epistomatal wax tubules was apparent. The stomata became covered by flat and solid wax resulting from the structural degradation of the wax crystalloids. Increasing the exhaust gas concentration in the chamber atmosphere exacerbated the degradation of the wax structure. Exhaust gas exposure induced aggregation and electron translucence of plastoglobuli, swelling of thylakoids, increase of cytoplasmic lipids and slight increase of vesiculation of cytoplasm in mesophyll cells of current and previous year needles. These changes were exemplified in current year needles. Damage to the epicuticular waxes and mesophyll ultrastructure of spruce needles most likely reflects the NO(x) and volatile hydrocarbon fraction. The alterations in epicuticular waxes and mesophyll ultrastructure can be related to accelerated senescence of the youngest, photosynthetically active, needle generation. The exhaust gas also resulted in decreased diffusive stomatal resistance at night which indicates that the exhaust gas exposure disturbed the gas exchange of spruce seedlings. The results show that even relatively short-term exposure to realistic concentrations of exhaust gas in the atmosphere can induce rather severe injuries to the needle surface structure as well as ultrastructure at the cellular level.     

蓄热式氧化炉在无机材料煅烧尾气处理中的应用

分子筛煅烧尾气中含有三乙胺、正丁胺等挥发性有机化合物（VOCs）,严重影响厂区及周边环境。为彻底治理有机废气污染,采用三床式蓄热式氧化炉（RTO）处理有机废气,通过优化调整控制工艺,以排烟温度控制法替代原有的排烟时间控制法。结果表明：排烟温度控制法可确保排烟温度保持在设计范围内,有效降低了排烟热损失;蓄热式氧化炉通过吸热-燃烧-放热周期性稳定运行,在天然气平均耗量4.5 m3·h-1的情况下,获得99%以上的VOCs去除效率,达到预期目标。蓄热式氧化法是一种经济、高效、稳定和安全的有机废气处理技术。     

Automobile exhaust gas as a source of aqueous phase OH radical in the atmosphere and its effects on physiological status of pine trees

Free radical generation potential of automobile exhaust gas was examined by measuring hydroxyl (OH) radical photo-formation rates in exhaust gas-scrubbing water. Effects of automobile exhausts on physiological status of Japanese red pine trees (Pinus densiflora Sieb. et Zucc.) were also investigated to elucidate the mechanism how the free radicals derived from exhaust gas damage higher plants. Gasoline and diesel exhaust gases were scrubbed into pure water. Potential photo-formation rates of OH radical in aqueous phase (normalized to sun light intensity of clear sky midday on May 1 at 34°N) for gasoline and diesel cars were ave. 51 and 107 μM h⁻¹ m⁻³ of exhaust gas, respectively. Nitrite was a dominant source (ca. 70-90%) of photochemical formation of OH radical in both gasoline and diesel car exhausts. The scrubbed solution of diesel car exhaust gas was sprayed for six times per week to needles of pine tree seedlings in open top chambers. Control, exhaust + mannitol (added as OH radical scavenger), and nitrite + nitrate standard solution (equivalent levels existed in the exhaust gas) were also sprayed. Two months sprays indicated that the sprayed solutions of diesel exhaust and nitrite + nitrate caused a decrease of maximum photosynthetic rate and stomata conductance in pine needles while the control and exhaust + mannitol solution showed no effects on photosynthetic activities of pine needles. These results indicated that OH radicals generated mainly from photolysis of nitrite occurring in the scrubbing solution of exhaust gas are responsible for the decrease of photosynthetic activities of pine needles.     

浙江省某印染企业VOCs的产生特征及去除特性

为探究印染行业生产过程中挥发性有机物(volatile organic compounds, VOCs)的产生特征及现有控制措施对VOCs的去除效果,选取浙江某典型印染企业作为研究对象,调查了该企业主要VOCs污染源(包括定型机、配料间及污水站)的废气产生特征,测定和评价了各废气处理装置对VOCs的去除效果。结果表明,该企业定型机、配料间及污水站产生的有组织废气总流量分别为8.6×10⁵、7.4×10⁴、2.8×10⁴ m³·h⁻¹,产生的VOCs平均浓度分别为14.7、9.0和14.9 mg·m⁻³,有组织废气源VOCs的年产生总量约为80 t。定型车间、印染车间和污水站附近无组织VOCs的平均浓度分别约为0.66、0.16和0.59 mg·m⁻³。产生的典型VOCs包括苯甲酸苄酯、五氟丙酸三十八烷酯、乙二醇单丁醚、十六烷、异喹啉等。定型机废气采用“冷却+静电”或“喷淋+静电”工艺处理,其对VOCs的去除率仅为2%~6%。配料间和污水站产生废气采用“碱洗+次氯酸钠洗涤”工艺处理,其对VOCs的去除率为8%~58%。研究结果可为印染行业VOCs污染控制提供参考。     

吸附冷凝回收与生物氧化联合工艺对炼油污水废气的处理

大气污染防治的形势日益严峻,为实现废气的达标排放,采用吸附冷凝回收与生物氧化联合工艺对炼油污水废气进行处理。结果表明,对污水构筑物进行加罩密封后,将废气收集及输送,采用分区收集、分类处理的工艺方法,先对废气收集系统的高浓度废气采用脱硫、吸附冷凝原理进行预处理,再与低浓度废气混合进入生物氧化滴滤段与过滤段进行处理,可有效去除炼油污水处理过程中各池体构筑物逸散出的H2S、有机硫化物、酚类、烃类等有害气体,实现废气的达标排放。其中,通过吸附冷凝回收工艺,高浓度段非甲烷总烃的去除率可稳定在60%以上,通过生物氧化联合处理工艺,低浓度段非甲烷总烃的去除率可稳定在40%以上,且氨、硫化氢、甲苯、二甲苯的总去除效果良好,可以有效改善周边区域的大气环境,满足国家标准规范排放要求及地方环境法规的要求。