共查询到19条相似文献,搜索用时 234 毫秒
1.
SOF-FTIR在化工厂区氨气排放通量测量中的应用 总被引:1,自引:0,他引:1
介绍了一种化工厂区污染气体排放通量实时监测的新方法,即太阳掩星法傅里叶变换红外光谱技术(SOF-FTIR),提出了复杂条件下的背景谱、测量谱和污染区域周边大气透过率谱获取模型。通过对欲监测的污染源区域周边做闭合环路连续测量以获得测量光谱,最终应用非线性最小二乘拟合算法对污染源区域污染气体的柱浓度信息进行反演,并结合实验时气象参数以及GPS信息得到该区域污染气体的排放通量。运用此方法实际遥测了某化工厂区氨气的排放情况,并对氨气气体浓度分布及排放通量进行了定量分析。相对于传统的FTIR监测方法,该方法操作简单、机动性强,在污染气体区域监测以及其他污染源污染排放应急监测等应用领域具有良好的应用前景。 相似文献
2.
本文主要介绍了一种快速测量区域大气痕量气体二维分布的方法——机载成像差分吸收光谱(differential optical absorption spectroscopy, DOAS)技术. 该技术基于成像光谱仪, 利用DOAS算法, 对痕量气体大范围分布快速扫描成像, 可实现污染源扩散趋势的可视化观测, 应用于污染源定位、污染源排放率监测、污染物传输演化等研究. 文中详细介绍了研制的机载成像DOAS系统, 并利用该系统开展飞行实验, 快速获取了飞行轨迹上空的NO2浓度分布. 实验中针对重点关注区域进行扫描测量, 成功获取了高分辨率的NO2二维分布图, 分析了污染扩散趋势, 并结合风场数据, 估算污染点源的NO2排放率为1570 kg/h. 相似文献
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4.
大气中二氧化碳浓度持续增高导致环境和气候变化等问题成为人们关注的焦点. 为了实时遥测二氧化碳气体柱浓度, 研究了一种地基低分辨遥测系统和实时光谱数据反演分析方法. 利用该系统在合肥地区进行了连续观测, 从太阳吸收光谱中实时获取了整层大气透过率. 采用逐线积分非线性最小二乘光谱反演算法, 从整层大气透过率中反演了二氧化碳柱浓度和氧气柱浓度, 并以氧气柱浓度为内标函数获得了二氧化碳干空气柱体积混合比, 精密度优于3%. 将2012年9月25日12时到15时本系统测量的二氧化碳干空气柱体积混合比均值与此时段过境本站点区域的日本温室气体卫星观测结果进行了比较, 两者偏差小于1%.可见, 该系统和方法具有很高的精密度和准确度, 是一种有效的温室气体观测手段.
关键词:
红外吸收光谱技术
遥测
二氧化碳
柱浓度 相似文献
5.
超光谱成像差分吸收光谱系统烟羽测量研究 总被引:3,自引:1,他引:2
研究一种测量污染气体(如SO2,NO2)二维分布的光学遥感方法,即采用超光谱成像差分吸收光谱(DOAS)系统在扫描转台上对污染源排放烟羽进行扫描测量,利用被动差分吸收光谱处理方法对采集到太阳散射光谱进行处理获得柱浓度,结合转台扫描,最终实现污染气体的二维成像解析.着重描述了基于成像差分吸收光谱仪、紫外镜头及扫描转台的超光谱成像差分吸收系统,并利用该系统对热电厂烟羽排放进行了外场测量,该技术为污染源实时成像测量提供了一种简便的方法. 相似文献
6.
采用加权函数修正的差分光学吸收光谱技术(weighting function modified differential optical absorption spectroscopy, WFM-DOAS)测量环境大气中的CO2垂直柱浓度. 以直射太阳光测量光谱为例, 演示了WFM-DOAS算法的实现过程. 将环境大气分为50层, 借助辐射传输模拟软件SCIATRAN对各个测量光谱进行了模拟计算, 获得了最小二乘法拟合所需的目标气体CO2及干扰气体H2O、CH4 的柱权重函数和太阳归一化光谱常量. 采用WFM-DOAS方法对一整天的直射太阳光测量光谱进行了反演, 得到的反演误差均小于3%. 最后比较了两种不同DOAS算法对同一条测量光谱的反演结果, 验证了WFM-DOAS算法在红外被动气体遥感的优越性.
关键词:
环境污染监测
光学测量技术
红外光谱
温室气体 相似文献
7.
被动差分光学吸收光谱法监测污染源排放总量研究 总被引:6,自引:1,他引:6
研究了一种测量污染源污染气体(如SO2、NO2)排放总量的光学遥测方法,即采用被动差分光学吸收光谱(DOAS)系统在移动平台(如汽车)上对污染源排放烟羽进行扫描测量,利用被动差分光学吸收光谱处理方法对系统采集的天顶太阳散射光谱进行处理获取柱密度,在结合测量时段的气象(风场)信息后获得污染气体的排放通量,最终得到排放总量。着重描述了获得烟羽垂直柱密度的差分光学吸收光谱方法以及污染气体排放通量的计算方法,并利用车载被动差分光学吸收光谱系统对某一热电厂SO2排放进行了外场测量,实验结果与在线设备的对比表明:这种基于被动差分光学吸收光谱光学遥测方法能够用于污染源排放总量的快速测量。 相似文献
8.
《光学学报》2015,(6)
介绍了一种测量烟羽污染气体二维分布的方法——成像差分吸收光谱(IDOAS)技术。该技术基于成像光谱仪,结合旋转平台实现对目标区域的二维扫描测量,获取目标区域的高光谱数据;采用差分吸收光谱(DOAS)算法对光谱进行处理,获取扫描区域内污染气体的二维分布图,进而对污染气体的分布及扩散趋势进行分析。对地基IDOAS系统及其测量原理进行了介绍,并开展外场实验,成功获取了电厂烟羽中的SO2二维分布图,实现电厂污染排放的可视化;对SO2排放率及平均浓度估算方法进行了分析,结合风速,利用获得的二维数据计算得到电厂SO2排放率及平均浓度分别为210 kg/h、6.7 mg/m3。 相似文献
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非分散红外吸收光谱法(NDIR)是CO浓度测量的主要手段之一.设计了NDIR的开放式CO气体测量系统及连续测量实验装置,对10种不同浓度的标准CO气体进行测量实验,分析了获取的40个实测数值.将遗传规划(GP)用于CO光强采样数据的建模,得到验证集的相关系数为0.999 7,验证集的相对误差最大值和平均相对误差分别为4... 相似文献
10.
大气污染的综合防治需要从不同尺度的区域出发,充分研究区域的环境特点,需要对空气质量有作用的多种因素进行全面系统的分析,获取大气污染物浓度时空分布是了解区域污染特征的重要途径。获取高空间分辨的大气污染物柱浓度分布情况是掌握区域污染程度的重要前提。由大气扩散模型,排放源周边的大气污染物的柱浓度服从高斯分布。将车载被动差分光学吸收光谱(DOAS)获取的对流层污染气体垂直柱浓度空间分布信息结合序贯高斯模拟方法重构了高空间分辨率的区域污染物柱浓度分布及其误差分布。分别选取工业园区(钢铁企业)、城市区域(北京市怀柔城区、北京市通州城区)等典型区块进行走航观测,获取观测路径上的NO2和HCHO柱浓度,结合地理信息网格化车载观测数据,利用序贯高斯模拟获取了观测区域的NO2和HCHO柱浓度分布以及污染物柱浓度误差分布,重点分析了该方法在排放特征不同的区域柱浓度分布模拟重构的可行性及重构结果的不确定性。某钢铁企业、怀柔城区、通州城区内污染源依次减少,气态污染物分布的结构复杂性依次降低。由半方差分析结果,某钢铁企业由于NO2排放源多,污染物柱浓度空间依赖性略弱,城市区域污染物柱浓度表现出强烈的空间相关性,并且整体呈现出了区域污染源越复杂,空间相关性的范围越小的特点。基于立体监测数据获取了观测区域百米空间分辨的污染物垂直柱浓度分布及误差分布,在不依赖下垫面数据、源清单数据或人口分布数据的基础上基于实测数据低成本地获取了重点工业区或城市区域气态污染物的分布细节,同已有的卫星遥感等方法获取污染气体垂直柱浓度分布相比,空间分辨率提高了2~3个数量级,同时通过柱浓度误差分布定量评估了模拟重构的准确性。针对不同排放特征的重点区域大气污染状况,提供了新的准确性可评价的实测手段,该方法对了解区域污染状况、污染控制对策及控制效果的评估具有重要作用。 相似文献
11.
《Current Applied Physics》2015,15(3):232-237
The microstructural properties of a GaN thin film grown on a Si(110) substrate under various ammonia (NH3)-flux conditions were observed to study growth mode and defect evolution. The surface flatness of GaN thin films was improved with the increase of the NH3 flux while the thickness was decreased by increasing the NH3 flux. In addition, the crystalline quality of the GaN film grown under the lower NH3 flux (100 sccm) was better than that of the film under the higher NH3 flux (400 sccm). The different dislocation behaviors depending on NH3 fluxes were observed; the low density of dislocations was measured and most of dislocations penetrating the thin film was mixed- and edge-type dislocations when GaN was grown under the low NH3 flux condition while the high density of dislocation and many mixed- and screw-type dislocations penetrating the film were observed in the GaN film grown under the high NH3 flux. These phenomena are demonstrated by using a kinetic model related to the role of NH3. 相似文献
12.
Kapuruge Don Kunkuma Amila Somarathne Ekenechukwu C. Okafor Daiki Sugawara Akihiro Hayakawa Hideaki Kobayashi 《Proceedings of the Combustion Institute》2021,38(4):5163-5170
This study examined the effects of OH concentration and temperature on the NO emission characteristics of turbulent, non-premixed methane (CH4)/ammonia (NH3)/air swirl flames in two-stage combustors at high pressure. Emission data were obtained using large-eddy simulations with a finite-rate chemistry method from model flames based on the energy fraction of NH3 (ENH3) in CH4/NH3 mixtures. Although NO emissions at the combustor exit were found to be significantly higher than those generated by CH4/air and NH3/air flames under both lean and stoichiometric primary zone conditions, these emissions could be lowered to approximately 300 ppm by employing far-rich equivalence ratios (?) of 1.3 to 1.4 in the primary zone. This effect was possibly due to the lower OH concentrations under far-rich conditions. An analysis of local flame characteristics using a newly developed mixture fraction equation for CH4/NH3/air flames indicated that the local temperature and NO and OH concentration distributions with local ? were qualitatively similar to those in NH3/air flames. That is, the maximum local NO and OH concentrations appeared at local ? of 0.9, although the maximum temperature was observed at local ? of 1.0. Both the temperature and OH concentration were found to gradually decrease with the partial replacement of CH4 with NH3. Consequently, NO emissions from CH4/NH3 flames were maximized at ENH3 in the range of 20% to 30%, after which the emissions decreased. Above 2100 K, the NO emissions from CH4/NH3 flames increased exponentially with temperature, which was not observed in NH3/air flames because of the lower flame temperatures in the latter. But, the maximum NO concentration in CH4/NH3 flames was occurred at a temperature slightly below the maximum temperature, just as in NH3/air flames. The apparent exponential increase in NO emissions from CH4/NH3 flames is attributed to a similar trend in the OH concentration at high temperatures. 相似文献
13.
Matthew J. Montgomery Hyunguk Kwon Jochen A.H. Dreyer Yuan Xuan Charles S. McEnally Lisa D. Pfefferle 《Proceedings of the Combustion Institute》2021,38(2):2497-2505
Due to issues surrounding carbon dioxide emissions from carbon-containing fuels, there is growing interest in ammonia (NH3) as an alternative combustion fuel. One attractive method of burning NH3 is to co-fire it with hydrocarbons, such as natural gas, and in this case soot formation is possible. To begin understanding the influence of NH3 on soot formation when co-fired with hydrocarbons, soot volume fractions and mole fractions of gas-phase species were computationally and experimentally interrogated for CH4 flames with up to 40% NH3 by volumetric fuel fraction. Mole fractions of gas-phase species, including C2H2 and C6H6, were measured with on-line electron impact mass spectrometry, and soot volume fractions were obtained via color-ratio pyrometry. The simulations employed a detailed chemical mechanism developed for capturing nitrogen interactions with hydrocarbons during combustion. The results are compared to findings in N2CH4 flames, in order to separate thermal and dilution effects from the chemical influence of NH3 on soot formation. Experimentally, C2H2 concentrations were found to decrease slightly for the NH3CH4 flames relative to N2CH4 flames, and a stronger suppression of C6H6 was found for NH3 relative to N2 additions. The measured results show a strong suppression of soot with the addition of NH3, with soot concentrations reduced by over a factor of 10 with addition of up to 20% or more NH3 by mole fraction. The model satisfactorily captured relative differences in maximum centerline C2H2, C6H6, and soot concentrations with addition of N2, but was unable to match measured differences in NH3CH4 flames. These results highlight the need for an improved understanding of fuel-nitrogen interactions with higher hydrocarbons to enable accurate models for predicting particulate emissions from NH3/hydrocarbon combustion. 相似文献
14.
Sakshi Sharma Shahir Hussain K. Sengupta S. S. Islam 《Applied Physics A: Materials Science & Processing》2013,111(3):965-974
Multi-walled carbon nanotube (MWCNT)/alumina (Al2O3) composite thin film-based low cost, rigid and highly efficient sensors were developed for trace level ammonia (NH3) gas sensing applications. Composite films were prepared by dispersing MWCNTs in varying concentration in alumina solution following the sol-gel process. The sensor response as a function MWCNT concentrations were measured and compared. The notable characteristics of these sensors are fast response time (10 minutes), and excellent reproducibility with detection level up to 6 ppm. Although poor NH3 desorption causes a high recovery time, fast and complete recovery was acquired using appropriate thermal treatment protocol. The sensitivity was found to be proportional to NH3 concentrations in the range 6–25 ppm and then gradually saturated at higher concentrations. However, a decrease in the sensor response was observed with increase in concentrations of MWCNTs. 相似文献
15.
A flux fusion method was used to obtain the various sizes of Eu3+-activated Y2O3 red phosphors. The flux material was selected as an independent variable to control the physical properties of phosphor particles and their effects on the morphology and size distribution of phosphors were examined by scanning electron microscopy. The concentration of the flux materials and synthetic temperature were optimized for maximal photoluminescence intensity. Fluoride-based flux materials were found to work for the crystal formation of Eu3+-activated Y2O3. In particular, when a BaF2 flux was used during the reaction at 1450 °C for 3 h, the photoluminescence (PL) intensity of Eu3+-activated Y2O3 was 25% higher than that without a flux and spherical phosphors had a mean particle size of 4-5 μm. The morphology and size distribution of the synthesized Eu3+-activated Y2O3 phosphor were predominantly dependent upon the type and concentration of flux material and synthetic temperature. 相似文献
16.
Hernan SeitzEstefanía Germán Alfredo Juan Beatriz Irigoyen 《Applied Surface Science》2012,258(8):3617-3623
We analyzed the adsorption of ammonia (NH3) on the VSbO4(1 1 0) catalyst surface using density functional theory (DFT) calculations. We followed the evolution of the chemical bonds between different atoms of the resulting NH3/VSbO4 system and the changes in the electronic structure of the catalyst. NH3 preferential adsorption geometries were analyzed through the crystal orbital overlap population (COOP) concept and the density of states (DOS) curves. The VSbO4(1 1 0) surface exhibits Lewis and Brønsted acid sites on which the ammonia molecule can interact. On the Lewis acid site, NH3 adsorption resulted in the interaction between the N and a surface V-isolated cation. On Brønsted acid site, N interacted with a surface H coming from the chemical dissociation of water. The COOP analysis indicate that NH3 interaction on the VSbO4(1 1 0) surface is weak. In addition, the DOS curves show more developed electronic interactions for NH3 adsorption on Lewis acid site than over Brønsted acid site. 相似文献
17.
It is shown in this paper that the form of the electron concentration distribution along the radius of the positive column in an oxygen discharge depends on the relative concentration of negative ions α = n-/ne in the plasma. It is found that in discharges in electronegative gases everywhere along the radius of the positive column, where α > 10, the electron concentration is equal to its value on the tube axis (plane electron distribution along the radius of the positive column). It is shown that an increase of the discharge current leads to the decrease of α and to the change of the distribution of profile ne from plane to parabolic. However, weak laminar oxygen pumping along the positive column leads to more plane an electron concentration distribution because an increase of the negative ions concentration takes place. It is induced by the decrease of oxygen atoms density on account of their carrying out by the flow. 相似文献
18.
O. D. Maslov 《Physics of Particles and Nuclei Letters》2016,13(4):521-525
The paper reports on the observation of spontaneous fission of nuclides, concentrated in fly ash during the combustion of high-carbon (graphite) material, chemogenic siliceous-carbonaceous rocks and carbonaceous shale in the mixture with brown coal. In the samples obtained, the spontaneous fission was measured by track method. The zones of precipitation of spontaneous fission of nuclides and their lighter homologues on thermochromatographic column were determined. A nuclide with a half-life of 62 days was detected in the alkaline trap. The chemical treatment procedure included co-precipitation with iron hydroxide, dissolution in NH4OH + H2O2 solution and distillation by heating up to 100°C followed by AgI co-precipitation. Based on the chemical behavior it can be concluded that the detected radionuclide belongs to the halides. The content of the parent nuclide in high-carbon (graphite) material and chemogenic siliceous-carbonaceous rock corresponds to 10–14 g/g. 相似文献
19.
本文利用量子化学计算方法,研究了甲胺和水复合离子团簇[(CH3NH2)(H2O)n]+的几何结构、能量和红外光谱,揭示了结构生长模型、氢键作用机制和质子转移机理. 研究结果表明,在[(CH3NH2)(H2O)n]+团簇中,甲胺甲基上的一个氢原子转移到氨基上,形成分子内质子转移的CH2NH3+离子核心结构模型,水分子作为氢键受体,与质子化氨基NH3+形成氢键. CH3NH2+离子核心结构模型没有CH2NH3+离子核心结构模型稳定. 在团簇的红外光谱中,CH振动、自由NH振动、氢键结合的NH振动和OH振动模式在CH3NH2+和CH2NH3+两种离子核心结构模型的理论计算红外光谱中明显不同,因此可用于鉴别甲胺水合离子团簇的结构模型,有助于理解甲胺和水复合团簇的氢键网络结构. 相似文献