Emission of volatile organic compounds (VOC) from tropical plant species in India

Foliar emission of volatile organic compounds (VOC) from common Indian plant species was measured. Dynamic flow enclosure technique was used and the gas samples were collected onto Tenax-GC/Carboseive cartridges. The Tenax-GC/Carboseive cartridges were attached to the thermal disorber sample injection system and the gas sample was analysed using gas chromatography (GC) with flame ionisation detection (FID). Fifty-one local plant species were screened, out of which 36 species were found to emit VOC (4 high emitter; 28 moderate emitter; and 4 low-emitter), while in the remaining 15 species no VOC emission was detected or the levels of emission were below detection limit (BDL). VOC emission was found to vary from one species to another. There was a marked seasonal and diurnal variation in VOC emission. The minimum and maximum VOC emission values were < 0.1 and 87 microgg(-1) dry leaf h(-1) in Ficus infectoria and Lantana camara respectively. Out of the 51 plant species studied, 13 species are reported here for the first time. Among the nine tree species (which were selected for detailed study), the highest average hourly emission (9.69+/-8.39 microgg(-1) dry leaf) was observed in Eucalyptus species and the minimum in Syzygium jambolanum (1.89+/-2.48 microgg(-1) dry leaf). An attempt has been made to compare VOC emission from different plant species between present study and the literature (tropical and other regions).     

基于小波神经网络的瓦斯涌出量预测研究

准确地预测瓦斯涌出量对于指导矿井设计和安全生产有重要意义,而瓦斯涌出量是一个与自然因素及开采技术等多因素有关的非线性建模问题。鉴于传统神经网络方法解决非线性问题收敛速度慢,易陷入局部最优解的缺陷,笔者提出一种既充分利用小波变换的时频局部化性质,又能结合神经网络的自学习能力的小波神经网络预测瓦斯涌出量的方法,并建立了预测模型。在此基础上,采用Delphi语言,设计了小波/BP神经网络仿真器。通过实例分析表明该方法较传统神经网络收敛迅速,预测精度高。     

采场低压通风控制有害气体涌出量新技术的研究与应用

基于空气动力学观点,将回采工作面与其后相随的采空区分成两大组成部分:一部分称为通风空间,其风流是有组织的,另一部分称为漏风空间,其风流是非组织性的。两空间相互敞开,又紧紧相邻、存在着密切的风流联系。当开采工作面上、下两端存在着风压差,就可以带动相邻的采空区陷落岩石的孔隙与裂隙中的气体流动,构成采空区中、深部区域的漏风源、汇。笔者提出的采场低压通风系统,采用砌隔漏风墙的方法,切断两空间联系。经现场井下多年应用实践研究后表明,其对于开采瓦斯含量大、煤与瓦斯突出严重的复杂煤层的矿井,尤其是对采空区瓦斯及有害气体涌出量大、且无条件进行瓦斯抽放的回采工作面,能有效地抑制和减少采场瓦斯和有害气体涌出量,且措施费用很低,很值得推广应用。     

重庆市基于排放绩效的火电行业二氧化硫总量控制研究

本文介绍了排放绩效及排放绩效方法在火电行业二氧化硫总量控制方面的应用，并对重庆市火电机组及其二氧化硫排放状况进行了全面调查，根据重庆市二氧化硫污染防治的需要制定了各时段机组“十一五”期间的排放绩效控制标准，利用排放绩效方法测算了重庆市火电行业二氧化硫总量控制目标，提出了总量配额分配方法。     

重点环保城市二氧化硫总量控制目标值的研究

根据城市的输送扩散污染特性和污染源排放结构制订出低、中、高和理想4种二氧化硫排放控制方案。根据高、中、低架源污染物排放 与地面环境质量之间的关系以及各重点城市年平均扩散系数,可以算出重点城市二氧化硫2010年总量控制方案对应的控制目标值。      

速度场系数在烟气流速测定中的应用与研究

烟气流速测定是气态污染源排放总量监测的重要内容,关键问题是如何将连续监测系统的固定点烟气流速转化为监测断面的平均烟气流速。通过用参比方法对连续监测系统流速测定值进行校准,求出该监测断面的速度场系数。通过对两套连续监测系统的校准全过程的研究,证明速度场系数为一基本稳定值,经一段时间复验后其变化仍在容许范围之内,可用其对连续监测系统进行流速校准。      

马鞍山市二氧化硫排放总量与污染控制方案

概述了马鞍山市二氧化硫污染现状,预测了规划年的二氧化硫排放量,提出了污染控制目标。针对该市冶金和电力等主要行业重点源二氧化硫排放及防治存在的问题,提出了一系列控制措施和重点治理项目。2000,2005和2010年二氧化硫排放总量控制目标可分别达到5.628万,5.005万及4.608万t,城区环境空气中的二氧化硫浓度将达到国家环境质量二级标准。      

Reconstruction of the methane fluxes from the west Siberia gas fields by the 3D regional chemical transport model

A 3D mesoscale tropospheric photochemical transport model of high spatial resolution has been developed and used for assessment of the methane concentrations and methane emission in the West Siberian region of intensive mining of natural gas and oil deposits. The model is validated against the measurements of methane concentration at the surface and in the lower troposphere collected during July 1993 and June 1996 experiments. Comparison of the simulated and observed concentrations allowed to estimate that during the above periods the average natural methane fluxes were as high as 65 mg m⁻² day⁻¹. The anthropogenic methane fluxes (leakage from gas deposits) integrated over model domain during the same time period were about 20% of the total methane emission from relevant areas.     

燃煤火电厂汞排放因子测试设计及案例分析

在火电厂锅炉煤的燃烧中,汞的迁移是个复杂的过程.在炉内高温下,几乎所有的汞以气态形式停留于烟气中,随着烟气温度的降低,汞被再分配到粉煤灰、炉渣和空气中.采用测试和衡算的方法,对火电厂汞排放因子进行测试和分析.结果表明:汞的迁移分配与煤中汞的赋存量、粉煤灰中可燃物碳的含量及烟气温度相关.煤燃烧后,进入粉煤灰中的汞占煤中汞含量的12.7%～31.3%,进入炉渣中的汞占0.9%～12.8%,大部分汞排入大气中,占67.8%～82.2%.      

温室气体减排问题中的公平性与效率问题

《联合国气候变化框架公约》的最终目的是减少人为温室气体排放,稳定大气温室气体浓度,避免气候系统受到人为的危险干扰。本文指出,在承担温室气体减排义务时,公平性与时间效率,以及公平性与空间效率都是相互冲突的,并提出了兼顾公平性和效率的方案。