冷凝-催化燃烧法处理乙烯厂富含水蒸气的恶臭废气

采用冷凝-催化燃烧法处理乙烯厂富含水蒸气的恶臭废气,冷凝过程能够有效地脱除废气中的水蒸气、联苯和联苯醚,催化燃烧过程能够有效地脱除不凝气中的烃类化合物.催化燃烧反应器内装填Pr、Pd、Ce多组分蜂窝状催化剂,在床层空速为15900～40000h-4、反应器入口气温度为30～350℃的条件下,反应器入口气中总烃的体积分数为64.9×10-6～691.0×10-6时,出口总烃的体积分数可降至5.2×10-6～20.0×10-6,总烃的去除率为90%以上,处理后的气体符合国家排放标准.     

非热强介质等离子体反应器用于臭味气体的分解

对非热强介质等离子体反应器用于臭味气体———氨、硫化氢、甲基硫醇的分解进行了试验研究。研究了施加电压、停留时间、初始浓度对臭味气体分解率的影响 ,并对氨的分解产物进行了初步分析。结果表明 ,在这 3种气体的初始体积分数分别为 2 5× 10 -6和 5 0× 10 -6的条件下 ,当施加电压为 16kV、停留时间为 0 .2 3s时 ,氨的分解率达到 97%以上 ;当停留时间为0 .2 3s时 ,硫化氢和甲基硫醇分别在 10kV和 8kV时达到 10 0 %的分解。     

国外动态

一种先进的无氢脱硫工艺问世ChemicalEngineeringProgress,2 0 0 3 ,99( 9) :14　　据悉 ,总部位于美国得克萨斯州圣安东尼的Valero能源公司近日在其位于路易斯安那州KrotzSprings的炼油厂开始运行一套 5 0桶 /d的柴油脱硫示范装置 ,首次试验Unipure公司发明的用于燃料脱硫的先进脱硫 (ASR )工艺。据Unipure公司负责该工艺商业化开发的副总Barlow介绍 ,ASR工艺可以将硫质量分数为 30 0× 10 - 6 ～ 30 0 0× 10 - 6的汽油或柴油燃料最终转换成硫质量分数低于 5×10 - 6 的超低含硫清洁燃料 ,而且与传统的加氢脱硫工艺相比具有投资省的…     

铈(Ⅳ)-吐温40-邻苯二酚化学发光体系测定废水中的邻苯二酚

基于在吐温40存在下邻苯二酚与铈(Ⅳ)在酸性介质中发生化学发光反应,建立了测定邻苯二酚化学发光分析法。该法测定邻苯二酚的线性范围为3.0×10-7～5.0×10-5mol/L,检测限为1.0×10-7mol/L,相对标准偏差为3.0%(邻苯二酚浓度为5.0×10-6mol/L,平行测定11次)。用该法测定实验室废水中的邻苯二酚,结果令人满意。     

混合二元酸中戊二酸的分离提纯

采用溶剂溶解和气泡结晶的方法从混合二元酸中分离、提纯戊二酸。考察了溶解温度、溶剂用量和结晶过程对戊二酸纯度和收率的影响 ,并确定了分离与提纯的最佳工艺条件。分离过程 :溶解温度 5 5℃、溶剂与二元酸用量比 30mL∶10g ;提纯过程 :结晶气速 5× 10 -6～ 8× 10 -6m3 /s、降温速率 1/ 3℃ /min、降温终点 2 0℃、结晶保温时间 2 0min、升温速率 1/ 2℃ /min、发汗终温 6 5℃、发汗保留时间 10min。在最佳工艺条件下分离、提纯得到的戊二酸纯度为 99 36 % ,戊二酸的回收率为 70 16 %。     

催化氧化法脱除黄磷尾气中的磷化氢和硫化氢

在常压、温度60~100℃、气体流量0.375~0.875 m3/h的条件下,利用自制的JC-4型催化剂可以深度脱除黄磷尾气中的磷化氢和硫化氢,使它们在产品气中的体积分数小于1×10-6,净化效率接近100%。该催化剂寿命长达6 000 m in,处理黄磷尾气能力为300 m3/kg。在36~50 m3/h黄磷尾气净化中试试验中,取得了同样的效果。     

6,6″-二甲基-4′-苯基-2,2′∶6′,2″-三联吡啶分光光度法测定水中的铁

以 6 ,6″-二甲基 - 4′-苯基 - 2 ,2′∶ 6′,2″-三联吡啶 (TPY )为络合剂 ,用分光光度法测定水中铁的含量。进行了波长、TPY乙醇溶液用量及显色时间等条件的选择。该分析方法表观摩尔吸光系数为 2 .17× 10 5 dm3· mol- 1 · cm- 1 ,变异系数为 3.9% ,加标回收率为 96 .4%～ 10 5 .6 %。[关键词 ]6 ,6″-二甲基 - 4′-苯基 - 2 ,2′∶ 6′,2″-三联吡啶 ;分光光度法 ;铁 ;水质分析以 6 ,6″-二甲基 - 4′-苯基 - 2 ,2′∶ 6′,2″-三联吡啶 (TPY )为络合剂 ,用分光光度法测定水中铁的含量。进行了波长、TPY乙醇溶液用量及显色时间等条件的选择。该分析方法表观摩尔吸光系数为 2 .17× 10 5 dm3· mol- 1 · cm- 1 ,变异系数为 3.9% ,加标回收率为 96 .4%～ 10 5 .6 %。     

美国提出更严格的饮用水砷标准

砷是生活饮用水中严格控制的有害成分之一。为确保饮用水的安全 ,美国环保局 (ＥＰＡ)最近又提出了更严格的饮用水中砷标准 ,从原先的 50× 10 - 6 降为 5.0× 10 - 6 ,这比 1993年世界卫生组织 (ＷＨＯ)规定的指导值 10× 10 - 6 还要低。欧盟成员国按ＷＨＯ规定实行 ,而加拿大的标准是 2 5× 10 - 6 。ＥＰＡ采取这一行动后 ,加拿大也将重新考虑。美国环保局对饮用水中砷标准从严主要来自于美国科学院的一份报告 ,认为老标准应尽快降低 ,因为报告发现长期暴露于 50× 10 - 6 的砷会导致皮肤、膀胱、肺和前列腺癌 ,还有一系列非致癌健康影…     

柴油低温临界吸收法回收装车挥发油气

研究了采用柴油低温临界吸收法回收装车挥发油气的效果。实验结果表明：按装车挥发油气中的总烃体积分数为20.88%、装车挥发油气流量为280 m³/h、年运行时间为2 668 h计,装置年回收油气量为291 t,装置年最大运行功率为206.770 MW,装置投资回收期为3 a;处理后净化气中的总烃体积分数为1.24%,排放质量浓度低于25 g/m³,油气回收率达95%。处理后净化气满足GB 20950—2007《储油库大气污染物排放标准》,取得了较好的环保效益和经济效益。     

电晕放电等离子体烟气脱硫工业化试验

在四川绵阳5000-20000 m3／h装置上进行了电晕放电等离子体烟气脱硫试验。试验结果表明,水蒸气／氨放电活化均能够提高烟气脱硫效率。在水蒸气／氨活化及脉冲电晕联合作用下,烟气温度60-70℃,烟气含湿总量约10％,SO2初始体积分数1500×10-6,氨硫摩尔比2:1,系统耗能率约为4 W·h／m3时,脱硫效率达到93％,形成的副产物中(NH4)2SO4与(NH4)2SO3的质量比大于95:5。     

催化氧化技术在橡胶废气处理中的应用

采用催化氧化技术处理热塑性丁苯橡胶( SBS)生产装置D线后处理单元废气,废气的非甲烷总烃去除率和环己烷去除率均达到98％以上,非甲烷总烃质量浓度达到DB11/447-2007《炼油与石油化学工业大气污染物排放标准》的要求(小于100 mg/m3).对SBS生产装置凝聚单元进行两釜流程改三釜流程后,催化氧化反应器入口非甲烷总烃质量浓度由( 3.84～5.82)×103 mg/m3降至( 2.48～2.63)×103 mg/m3,反应器出口非甲烷总烃质量浓度均小于50 mg/m3.凝聚单元改造并采用催化氧化技术处理废气后,每年节约费用约80万元.     

基于SCREEN3的燃煤电厂海岸线熏烟问题研究

以2×300MW、2×600MW、2×1000MW海边燃煤电厂为例,采用SCREEN3模式利用正交试验法研究了海岸线熏烟和常规气象条件下,不同烟囱高度、不同排烟温度、不同离岸距离时最大落地浓度及其发生距离。结果表明：对于海边大型燃煤电厂,海岸线熏烟的发生与离岸距离、烟囱高度、排烟温度等因素有关;海岸线熏烟最大落地浓度（Smax）是常规气象条件下最大落地浓度（Cmax）的2倍以上,有时甚至达到4倍以上。Smax和Cmax均随排烟温度的升高而降低,Smax随烟囱离岸距离的增加而升高;熏烟最大落地浓度的发生距离（SL）远大于常规气象条件下最大落地浓度的发生距离（CL）,两者均随烟囱高度和排烟温度的升高而增加,SL随离岸距离的增加而缩短;对于离岸距离在3km以内的海边大型燃煤电厂,在环境影响评价时对厂址周边1.3～7.7km范围内有环境敏感点的区域要特别关注海岸线熏烟问题。     

Landfill gas upgrading with countercurrent water wash

A pilot-scale countercurrent absorption process for upgrading landfill gas to produce vehicle fuel was studied using absorption and desorption units and water as absorbent. The height-to-diameter ratio of the absorption column used was 3:1 instead of the more conventionally used 20:1 ratio, and a higher pressure was used along with a lower water flow rate. The effects of pressure (10-30bar) and water and gas flow-ratios on the upgrading process were studied. Methane content in the product gas increased to near or above 90% with both gas flows (50 and 100l/min) used at over 20bar pressure with 10l/min water flow and at 30bar pressure with 5l/min water flow. Carbon dioxide content with these upgrading parameters ranged from 3.2% to 4.8%. The remaining fraction of the product gas was nitrogen (from 6% to 7%), while hydrogen sulphide was removed to below the detection limit with all of the upgrading parameters used. The methane content of exhaust gas increased with increasing pressure. In conclusion, the pilot-scale gas upgrading process studied here appears to be able to produce gas with high energy content (>90% methane), apparently suitable as vehicle fuel, from landfill gas.     

Experimental research on emission and removal of dioxins in flue gas from a co-combustion of MSW and coal incinerator

This paper describes the experimental study of dioxins removal from flue gas from a co-combustion municipal solid waste and coal incinerator by means of a fluidized absorption tower and a fabric filter. A test rig has been set up. The flow rate of flue gas of the test rig is 150-2000 m3/h. The system was composed of a humidification and cooling system, an absorption tower, a demister, a slurry make-up tank, a desilter, a fabric filter and a measurement system. The total height of the absorption tower was 6.5m, and the diameter of the reactor pool was 1.2 m. When the absorbent was 1% limestone slurry, the recirculation ratio was 3, the jet rate was 5-15 m/s and the submerged depth of the bubbling pipe under the slurry was 0.14 m, the removal efficiency for dioxins was 99.35%. The concentration of dioxins in the treated flue gas was 0.1573 x 10(-13)kg/Nm3 and the concentration of oxygen was 11%. This concentration is comparable to the emission standards of other developed countries.     

酶联免疫吸附分析法测定环境水体中的萘

使用自制的包被原和抗萘多克隆兔抗体,建立了测定环境水体中痕量萘的间接竞争酶联免疫吸附法,并优化了实验条件.工作曲线线性方程为I=8.394logρ+50.21(I为抑制率,ρ为萘的质量浓度),线性范围10~(-3)～10 μg/L内的相关系数为0.985 6,方法灵敏度为0.944 μg/L,检出限为0.250 ng/L,回收率为86.00%～106.00%,批间误差为5.00%～15.00%,批内误差为2.00%～8.00%,与四种结构类似物的交叉率均小于14.0%.     

Nanosilver impact on methanogenesis and biogas production from municipal solid waste

Silver nanoparticles (AgNPs, nanosilver) released from industrial activities and consumer products may be disposed directly or indirectly in sanitary landfills. To determine the impact of AgNPs on anaerobic digestion of landfill waste, municipal solid waste (MSW) was loaded in identical landfill bioreactors (9L volume each) and exposed to AgNPs (average particle size=21nm) at the final concentrations of 0, 1, and 10mgAg/kg solids. The landfill anaerobic digestion was carried out for more than 250 days, during which time the cumulative biogas production was recorded automatically and the chemical property changes of leachates were analyzed. There were no significant differences in the cumulative biogas volume or gas production rate between the groups of control and 1mgAg/kg. However, landfill solids exposed to AgNPs at 10mg/kg resulted in the reduced biogas production, the accumulation of volatile fatty acids (including acetic acid), and the prolonged period of low leachate pH (between 5 and 6). Quantitative PCR results after day 100 indicated that the total copy numbers of 16S rRNA gene of methanogens in the groups of control and 1mgAgNPs/kg were 1.97±0.21×10(7) and 0.90±0.03×10(7), respectively. These numbers were significantly reduced to 5.79±2.83×10(5)(copies/mL) in the bioreactor treated with 10mgAgNPs/kg. The results suggest that AgNPs at the concentration of 1mg/kg solids have minimal impact on landfill anaerobic digestion, but a concentration at 10mg/kg or higher inhibit methanogenesis and biogas production from MSW.     

Indirect measurements of field-scale hydraulic conductivity of waste from two landfill sites

Management and prediction of the movement and distribution of fluids in large landfills is important for various reasons. Bioreactor landfill technology shows promise, but in arid or semi-arid regions, the natural content of landfilled waste may be low, thus requiring addition of significant volumes of water. In more humid locations, landfills can become saturated, flooding gas collection systems and causing sideslope leachate seeps or other undesirable occurrences. This paper compares results from two different approaches to monitoring water in waste. At the Brock West Landfill in eastern Canada, positive pore pressures were measured at various depths in saturated waste. The downward seepage flux through the waste is known, thus the vertical saturated hydraulic conductivity of the waste at this landfill was determined to be 3 × 10(-7)cm/s. By comparison, the Spadina Landfill in western Canada is predominantly unsaturated. The infiltration of moisture into the waste was measured using moisture sensors installed in boreholes which determined arrival time for moisture fronts resulting from major precipitation events as well as longer-term change in moisture content resulting from unsaturated drainage during winter when frozen ground prevented infiltration. The unsaturated hydraulic conductivity calculated from these data ranged from approximately 10(-6)cm/s for the slow winter drainage in the absence of significant recharge to 10(-2)cm/s or higher for shallow waste subject to high infiltration through apparent preferential pathways. These two very different approaches to field-scale measurements of vertical hydraulic conductivity provide insight into the nature of fluid movement in saturated and unsaturated waste masses. It is suggested that the principles of unsaturated seepage apply reasonably well for landfilled waste and that the hydraulic behavior of waste is profoundly influenced by the nature and size of voids and by the degree of saturation prevailing in the landfill.     

660MW机组烟气循环流化床干法脱硫塔入口气流分布的试验研究

以某火电厂2×660MW机组循环流化床干法脱硫气流模拟试验为研究对象，采用速度分布不均匀度的概念，详细研究各种工况下入口烟道导流形式对脱硫塔文丘里速度场分布的影响。研究表明。通过合理设置入口烟道的导流装置，可满足各种工况下CFB-FGD脱硫塔的文丘里管段和反应器段的气流均布，为干法脱硫大型化的气流分布试验研究提供借鉴。     

The influence of atmospheric pressure on landfill methane emissions

Landfills are the largest source of anthropogenic methane (CH4) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH4 emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH4 emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m3 CH4 min(-1). A simple regression model of our results was used to calculate an annual emission rate of 8.4 x 10(6) m3 CH4 year(-1). These data, along with CH4 oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH4 generation at this landfill. A reported gas collection rate of 7.1 x 10(6) m3 CH4 year(-1) and an estimated annual rate of CH4 oxidation by cover soils of 1.2 x 10(6) m3 CH4 year(-1) resulted in a calculated annual CH4 generation rate of 16.7 x 10(6) m3 CH4 year(-1). These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.     

Effectiveness of compacted soil liner as a gas barrier layer in the landfill final cover system

A compacted soil liner (CSL) has been widely used as a single barrier layer or a part of composite barrier layer in the landfill final cover system to prevent water infiltration into solid wastes for its acceptable hydraulic permeability. This study was conducted to test whether the CSL was also effective in prohibiting landfill gas emissions. For this purpose, three different compaction methods (i.e., reduced, standard, and modified Proctor methods) were used to prepare the soil specimens, with nitrogen as gas, and with water and heptane as liquid permeants. Measured gas permeability ranged from 2.03x10(-10) to 4.96x10(-9)cm(2), which was a magnitude of two or three orders greater than hydraulic permeability (9.60x10(-13) to 1.05x10(-11)cm(2)). The difference between gas and hydraulic permeabilities can be explained by gas slippage, which makes gas more permeable, and by soil-water interaction, which impedes water flow and then makes water less permeable. This explanation was also supported by the result that a liquid permeability measured with heptane as a non-polar liquid was similar to the intrinsic gas permeability. The data demonstrate that hydraulic requirement for the CSL is not enough to control the gas emissions from a landfill.