点排放源中二氧化碳浓度的测量研究

大气中温室气体浓度的增加引起的全球气候变化是世界关注的焦点问题。在所有的排放源中,固定排放源排放的二氧化碳气体是温室效应的主要因素。政府间气候变化专门委员会(IPCC)将直接测量排放量方法列为温室气体排放清单统计的最高等级,以提高数据统计精度。为了实现排放量的精确测量,固定排放源浓度直接测量至关重要。基于分析吸收光谱建立了相对于纯气体的测量方法,通过多次反射直接吸收光谱技术,建立了精确测量二氧化碳浓度的相对法装置,测量了293 K和0~13 kPa下二氧化碳在6 362.5 cm^-1的(30012)←(00001)R20e跃迁谱线,通过与纯二氧化碳吸收面积的比较得到15%,35%,50%和75%二氧化碳混合物的浓度。结果表明与天平称重法得到的结果具有很好的一致性,相对扩展测量不确定度在0.7%以下(k=2)。     

基于多次反射直接吸收精确测量二氧化碳浓度的研究

二氧化碳气体排放过多是造成温室效应的主要原因,对全球环境及生态系统产生了深远影响。企业燃料燃烧产生的二氧化碳是城市区域碳排放的主要来源。为了通过碳排放交易来实现企业减排,就必须对企业烟囱排放二氧化碳进行精确的计量,而企业烟囱排放的二氧化碳含量一般在20%以下,需要建立高准确度的现场测量方法。通过多次反射吸收光谱技术精确获得二氧化碳在6 361. 25 cm^-1的(30012)←(00001) R18e跃迁谱线信息,进一步结合理想气体方程来精确获得15%,10%,5%和1%二氧化碳/氮气(氮气为平衡气体)混合物的浓度。结果表明所建立的装置和方法能够快速精确地测量待测气体的浓度,测量结果与基于天平的称重法相当,扩展相对不确定度小于0. 65%(k=2)。     

CO的第二泛频(3←0)跃迁谱线线形强度测量研究

CO分子是监测大气污染气体的优异示踪气体,要实现对CO分子实时监控就需要做到对气体浓度的精确快速测量。气体分子浓度测量可以利用测量吸收光谱和谱线线形强度得到,CO的(3←0)泛频谱带是吸收较弱的跃迁波段,利用以干空气为缓冲气体的200μmol/mol的CO混合物,基于稳频的光腔衰荡装置测量了在温度293K、压力13~93kPa下的CO分子R支3条跃迁谱线的吸收光谱。HTP(Hartmann-Tran profile)线形被用来获得这些谱线的线形强度,测量结果的相对标准不确定度优于1%,与国际HITRAN、HITEMP和GEISA光谱数据库比较,相对偏差小于4%。     

基于傅里叶红外光谱仪的高温含水烟气中低浓度一氧化氮精确测量研究

随着国家超低排放政策的深入,对烟气中污染物浓度精确测量提出了更高的要求.基于傅里叶红外光谱仪建立了高温含水条件下一氧化氮(NO)气体精确测量系统,在191℃条件下测量了含5％ ～ 20％水蒸气与摩尔分数为5 ～ 40 μmol/mol NO混合前后的吸收光谱,通过修正混合物中H2O的吸光度来精确确定NO浓度,并评价了系...     

国内外水泥企业碳排放量化方法比较

水泥企业的各种CO2排放源中,生料煅烧过程中碳酸盐矿物分解产生的排放量大,且影响因素较多,不确定性较大,是水泥企业碳排放量化的重点和难点。本文通过对国际水泥可持续性倡议行动组织（CSI）和我国的《水泥生产企业CO2排放量计算方法》中的CO2量化方法进行分析与比较,以期为我国即将开展的碳核查提供参考。     

南京地区碳气溶胶的数值模拟研究

根据常规的SO2排放源资料以及NOx和HC交通源排放资料,建立了一种估算城市地区黑碳(BC)、有机碳(OC)源排放清单的方法,并利用此方法建立了南京地区碳气溶胶的源排放清单。同时运用NJU-CAQPS模式系统及二次有机气溶胶模式模拟分析了南京地区一次碳气溶胶(BC)、一次有机碳(POC)和二次有机气溶胶(SOC)的浓度分布特征。结果表明:在南京地区,机动车直接排放对城区一次碳气溶胶贡献率达到67.5%,机动车污染已成为主要来源;大气中的碳气溶胶浓度受到交通源(日变化)和气象条件(太阳辐射、温度、大气层结等)的共同影响;OC与BC的质量比冬季高于夏季,平均为2.62;SOC与OC的质量比夏季高于冬季,平均为19.8%。     

聚醚共聚酰胺复合气体分离膜对CO2/N2分离性能的研究

以烟道气中CO2的捕集为研究背景,以聚醚共聚酰胺Pebax1657嵌段共聚物为选择层膜材料,采用浸渍涂覆法,制备具有超薄分离皮层的PEI/PDMS/Pebax1657/PDMS多层复合气体分离膜,研究复合气体分离膜对CO2/N2混合气的分离特性.由于CO2的增塑作用,复合膜对CO2/N2混合气的分离系数为40左右,低于其理想分离系数.操作压力和原料气中CO2浓度对复合膜的渗透分离性能以及混合气的分离效果影响显著.在实际应用中,可通过调节膜两侧操作压力来提高CO2的富集浓度.     

直喷柴油机两种燃烧方式混合气形成的比较

利用KIVA-3V软件模拟了柴油机两种燃烧方式的混合气形成过程中的浓度场和温度场.模拟计算与实验结果表明,在常规柴油机燃烧方式中,燃油边喷边烧,混合气浓度和温度变化很大,导致预混合燃烧和扩散燃烧并存,NOx和碳烟比较高,CO和HC排放很低;利用早喷可以形成浓度场和温度场分层分布的均质混合气,实现均质充量压燃(HCCI)燃烧,碳烟和NOx很低,但CO和未燃烧的燃油排放很高.     

基于红外吸收光谱技术的CO2同位素测量研究进展

全球气候变暖形势加剧,温室气体排放是关键因素之一。二氧化碳作为主要温室气体,对其高精度监测技术是实现温室气体追踪的基础。在此基础上监测二氧化碳同位素组份,不仅可以实现高精度浓度监测,还能够区分不同排放源的碳循环过程贡献,实现人为排放和自然排放的追踪和溯源。发展高精度二氧化碳同位素监测技术对提升碳排放清单准确性,优化碳减排措施等具有重要意义。在自然界中,碳同位素气体浓度通常为大气浓度的10^-6倍,并受测量条件的影响,这导致了碳同位素测量难度加大。综述了红外吸收光谱技术测量二氧化碳稳定同位素浓度的研究进展,分析了高灵敏度稳频光腔衰荡光谱技术的原理及研究进展,并展望了稳定同位素光谱研究的未来方向。光腔衰荡光谱技术作为新兴光学检测技术,克服了传统方法测量精度不足、灵敏度低等缺陷,或成为新一代温室气体及同位素丰度测量标准方法。     

怠速启停微混车用AGM电池

<正>一、怠速启停微混车简介随着各国对气候变化的日益关注以及人们环保意识的逐步提高,降低汽车尾气排放的呼声也越来越高。当前,世界范围内机动车辆越来越多,其对环境的不利影响也越来越明显。在全球温室气体排放量中,机动车辆污染排放占相当比重,在欧盟国家,道路运输排放的二氧化碳(CO2)约占CO2排放总量的20%,其中轿车排放的CO2占道路运输排放的CO2量的一半以上。近年来,我国雾霾天气频发,中科院"大气雾霾追因与控制"专项组研究认为:机动车污染排放是造成雾霾天气的"主谋"之一。就北京而言,机动车的碳排放是城市PM2.5的最大来源,约为1/4。     

1.6微米附近氮气展宽的一氧化碳分子线形的研究

基于稳频的光腔衰荡光谱法是近年来发展的一种具有高灵敏度和准确性的测量痕量成分的方法,分子线形是影响光谱法测量成分的关键因素。利用基于稳频的光腔衰荡装置测量了一氧化碳R12(3←0)分子光谱,6种常用的分子线形被用来研究分子吸收光谱参数间的关系,包含压力相关的展宽、吸收峰面积和碰撞变窄效应,以及速度变化压窄和速度相依赖弛豫速率变窄效应的相关联等。研究结果表明pCqSDNGP线形能满足描述CO分子线形的需要。     

Direct determination of carbon dioxide in aqueous solution using mid-infrared quantum cascade lasers

A method for the direct determination of carbon dioxide in aqueous solutions using a room-temperature mid-infrared (MIR) quantum cascade laser at 2330 cm(-1) is reported. The absorption values of different carbon dioxide concentrations were measured in a 119 microm CaF2 flow-through cell. An optical system made of parabolic mirrors was used to probe the flow cell and to focus the laser beam on the mercury cadmium telluride (MCT) detector. Aqueous carbon dioxide standards were prepared by feeding different mixtures of gaseous N2 and CO2 through wash bottles at controlled temperature. The concentration of the dissolved CO2 was calculated according to Henry's law, taking into account the temperature and the partial pressure of CO2. The carbon dioxide standards were connected via a selection valve to a peristaltic pump for subsequent, automated measurement in the flow-through cell. A calibration curve was obtained in the range of 0.338 to 1.350 g/L CO2 with a standard deviation of the method sxo equal to 19.4 mg/L CO2. The limit of detection was calculated as three times the baseline noise over time and was determined to be 39 mg/L.     

In situ combustion measurements of CO with diode-laser absorption near 2.3 microm

In situ measurements of CO concentration were recorded with tunable diode-laser absorption spectroscopy techniques in both the exhaust and the immediate post-flame regions of an atmospheric-pressure flat-flame burner operating on ethylene air. Two room-temperature cw single-mode InGaAsSb/AlGaAsSb diode lasers operating near 2.3 microm were tuned over individual transitions in the CO first overtone band (v' = 2 <-- v" = 0) to record high-resolution absorption line shapes in the exhaust duct [79 cm above the burner, approximately 470 K; R(15) transition at 4311.96 cm(-1)] and the immediate postflame zone [1.5 cm above the burner, 1820-1975 K; R(30) transition at 4343.81 cm(-1)]. The CO concentration was determined from the measured absorption and the gas temperature, which was monitored with type-S thermocouples. For measurements in the exhaust duct, the noise-equivalent absorbance was approximately 3 x 10(-5) (50-kHz detection bandwidth, 50-sweep average, 0.1-s total measurement time), which corresponds to a CO detection limit of 1.5 ppm m at 470 K. Wavelength modulation spectroscopy techniques were used to improve the detection limit in the exhaust to approximately 0.1 ppm m (approximately 500-Hz detection bandwidth, 20-sweep average, 0.4-s total measurement time). For measurements in the immediate postflame zone, the measured CO concentrations in the fuel-rich flames were in good agreement with chemical equilibrium predictions. These experiments demonstrate the utility of diode-laser absorption sensors operating near 2.3 microm for in situ combustion emission monitoring and combustion diagnostics.     

Measurements of collisional broadening coefficients by infrared polarization spectroscopy

We present measurements of collisional broadening coefficients, obtained at atmospheric pressure, by polarization spectroscopy. Using tunable single mode laser radiation at approximately 2 microm, high-resolution infrared polarization spectra were recorded for CO2-Ar and CO2-He binary mixtures. The recorded polarization spectra were fitted with a Lorentzian cubed function form to obtain the broadening coefficients. The full-width at half-maxima (FWHM) collisional broadening rates of CO2 by Ar and He, for the R14 (12 degrees1<--00 degrees0) line, have been determined to be 0.161+/-0.018 cm-1 atm-1 and 0.1823+/-0.0032 cm-1 atm-1, respectively.     

Pure rotational coherent anti-Stokes Raman spectroscopy in mixtures of CO and N2

We present a model for quantitative measurements in binary mixtures of nitrogen and carbon monoxide by the use of dual-broadband rotational coherent anti-Stokes Raman spectroscopy. The model has been compared with experimental rotational coherent anti-Stokes Raman scattering spectra recorded within the temperature range of 294-702 K. Temperatures and concentrations were evaluated by spectral fits using libraries of theoretically calculated spectra. The relative error of the temperature measurements was 1-2%, and the absolute error of the CO concentration measurements was <0.5% for temperatures < or =600 K. For higher temperatures, the gas composition was not chemically stable, and we observed a conversion of CO to CO2. The influence of important spectroscopic parameters such as the anisotropic polarizability and Raman line-broadening coefficients are discussed in terms of concentration measurements. In particular, it is shown that the CO concentration measurement was more accurate if N2-CO and CO-N2 line-broadening coefficients were included in the calculation. The applicability of the model for quantitative flame measurements is demonstrated by measuring CO concentrations in ethylene/air flames.     

Real-time fourier transform-infrared analysis of carbon monoxide and nitric oxide in sidestream cigarette smoke

Fourier transform infrared (FT-IR) spectroscopy was compared directly to independent standard analytical techniques for the routine measurement of carbon monoxide (CO) and nitric oxide (NO) yields from cigarette sidestream smoke. The FT-IR instrument was configured in-line with a nondispersive infrared (NDIR) analyzer for CO analysis and a chemiluminescence (CL) analyzer for NO analysis to monitor the sidestream smoke from a single port of a linear smoking machine. A cold trap was inserted prior to the FT-IR to minimize the levels of vapor phase interferents, such as water. Univariate and multivariate regression analysis were evaluated for the prediction of cigarette yield from time-resolved spectral data at 1, 2, 4 and 8 cm-1 spectral resolution. Regressions were developed using three different spectral ranges including unique rotation-vibration lines, the R-branch, and the entire absorption band. As per standard methods, yields were calculated from the concentration traces generated during the smoke runs for five different cigarettes spanning the expected range of mainstream total particulate matter deliveries. The FT-IR traces for the smoke runs revealed improved temporal resolution yielding analytical information from smoke generated in between puffs. The performance between the validation methods and the FT-IR calibrations was statistically compared. In general, for the determination of CO, the FT-IR calibrations underestimated the yield measured by NDIR by less than 10%. For the NO measurement, the univariate FT-IR calibrations overestimated the NO yield measured by the CL analyzer, whereas the partial least squares (PLS) calibrations showed good agreement. PLS calibrations were developed for both analytes providing no significant difference when compared to the respective standard analytical techniques. Results for sidestream CO and NO yields for Kentucky reference cigarette 1R4F utilizing 8 cm-1 calibrations compared favorably to values reported elsewhere in the literature. Hence, calibration of the FT-IR system at 8 cm-1 spectral resolution clearly revealed the potential of this method, providing enhanced temporal resolution, simultaneous determination of several smoke components, and reduced complexity of the experimental setup in contrast to the standard techniques.     

Characterization of C-N Thin Films Prepared by Ion Beam Sputtering

C-N thin films have been prepared by ion beam sputtering using pure N2 as discharge gas. The ratio N/C of the films measured by Auger spectrum is 20% on an average. The results of X-ray diffraction and transmission electron microscopy show that β-C3N4 phase exists in the films. Xray photoelectron spectroscopy shows that nitrogen is mostly combined with carbon with triple (C=N) and double (C=N) bonds. The IR absorption shows an absorption bond near 2185 cm-1assigned to the C=N, no trace of C-C bond was observed