Protea atmosFIR在排放和环境空气甲醛测量中的应用

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    Accurate Continuous Formaldehyde Measurement -In emissions and ambient air applications

准确的连续甲醛测量 - 在排放和环境空气应用中

    Formaldehyde (HCHO) is the simplest aldehyde species and ispresent, or generated by, many sources (both natural and industrial). Itis classed as a substance that is toxic and harmful to human health.Naturally, HCHO is emitted to the atmosphere from biogenic sourcessuch as forest fires and the breakdown of organic materials. Industryhas added to this and HCHO is found in emissions to atmospherefrom gas engines burning natural gas, due to incomplete combustion.Materials used in the construction industry are a major source ofambient formaldehyde levels in the air. Wood based products usedin domestic and commercial buildings, such as insulation materialsmanufactured with urea-formaldehyde, and melamine-formaldehyderesins used on wood panels, chipboard, medium density fibreboardand laminate materials, all give rise to HCHO emissions. The industriesproducing these materials will be major sources of environmentalemissions and as such need to be able to measure and control theirHCHO emissions.
    甲醛（HCHO）是最简单的醛类物质，存在或由许多来源（天然和工业来源）产生。它被归类为对人体健康有毒且有害的物质。当然，HCHO从生物来源如森林火灾和有机物质的分解排放到大气中。工业增加了甲醛的排放，HCHO被发现燃烧天然气的燃气发动机由于燃烧不完全而向大气排放。建筑业中使用的材料是空气中环境甲醛含量的主要来源。用于家庭和商业建筑的木质产品，例如用脲醛制造的绝缘材料，以及用于木板，刨花板，中密度纤维板和层压材料的三聚氰胺 - 甲醛树脂，都会产生HCHO排放。生产这些材料的行业将成为环境排放的主要来源，因此需要能够测量和控制其HCHO排放。
    The use of HCHO containing products in the wider world has given rise to high background levels of HCHO in indoor ambient air
too. While not always at levels that will pose a health issue for the population, levels of HCHO can have a detrimental effect to museum
artefacts for example and so the monitoring and control of ambient HCHO is crucial.  
    在更广泛的世界中使用含有HCHO的产品也导致室内环境空气中HCHO的高背景气水平。 虽然并非总是处于对人群造成健康问题的水平，但HCHO的水平可能会对博物馆的人工制品产生不利影响，因此对环境HCHO的监测和控制至关重要。
    For many years, phenol-formaldehyde has been used as an embalming fluid in hospital and medical research laboratories. Persons working in such close proximity to the HCHO emissions need to be protected from high levels of HCHO and so workplaces have a duty to monitor and ideally control the ambient air to reduce HCHO to safe levels.
   多年来，苯酚 - 甲醛已被用作医院和医学研究实验室的防腐液。 需要保护在HCHO排放附近工作的人员免受高水平的HCHO影响，因此工作场所有责任监测并理想地控制环境空气，以将HCHO降低到安全水平。

   

Figure 1 - HCHO calibration spectra at 1cm-1, 4cm-1 and 8cm-1 resolutions. 1cm-1 can clearly be seen to have sharper and high absorption peaks, making identifcation and measurement of low HCHO concentrations possible.

图1 中 -  1cm-1,4cm-1和8cm-1分辨率下的HCHO校准光谱。 可以清楚地看到1cm-1具有更尖锐和高吸收峰，使得可以识别和测量低HCHO浓度。

     atmosFIR Platform atmosFIR平台
     Protea’s latest atmosFIR product line of FTIR gas analysers is ideal for accurate quantitative continuous formaldehyde monitoring, both in industrial emissions and ambient air applications. The atmosFIR analyser range is an extractive gas analyser platform where the gas sample to be measured is sampled through the analyser gas cell continually. By measuring the full infrared spectrum in real-time, we can identify and quantify the absorption peaks due to HCHO。
     Protea最新的atmosFIR FTIR气体分析仪产品系列是工业排放和环境空气应用中精确定量连续甲醛监测的理想选择。 atmosFIR分析仪系列是一种萃取气体分析仪平台，通过分析仪气室连续对待测气体样品进行采样。 通过实时测量全红外光谱，我们可以识别和量化HCHO引起的吸收峰。
     The atmosFIR product range is a high resolution FTIR analyser. It runs at a resolution of up to 0.7cm-1 as standard, with a 0.5cm-1 version available as an option. Compared to lower resolution techniques, this means that the absorption peaks due to HCHO can clearly be identifed, at a higher intensity than lower resolution, meaning that lower detectable limits of HCHO are possible. See Figure 1 which compares HCHO spectra at different resolutions. Even in crossinterfering backgrounds of other gases the detectable limits of HCHO can be low enough to meet the requirements of legislative reporting.
     atmosFIR产品系列是高分辨率FTIR分析仪。 它的标准分辨率高达0.7cm-1，可选配0.5cm-1版本。 与较低分辨率技术相比，这意味着可以以比较低分辨率更高的强度清楚地识别由HCHO引起的吸收峰，这意味着HCHO的较低可检测极限是可能的。 参见图1，它比较了不同分辨率下的HCHO光谱。 即使在交叉干扰其他气体的背景下，HCHO的可检测限度也足够低，以满足立法报告的要求。

    Industrial Emissions工业排放
    The atmosFIR AFS model offers a complete continuous emissions measurement system in a single analyser. As such it can measure a suite of combustion gases from emissions sources, including formaldehyde. For incineration plants and natural gas engines having to control and report HCHO levels it is the ideal tool for periodic or continuous measurements。
   atmosFIR AFS型号在单个分析仪中提供完整的连续排放测量系统。 因此，它可以测量来自排放源的一套燃烧气体，包括甲醛。 对于必须控制和报告HCHO水平的垃圾焚烧厂和天然气发动机，它是定期或连续测量的理想工具。

Figure 2 - atmosFIR AFS analyser for HCHO measurement in emissions monitoring applications.  

图2  - 用于排放监测应用中HCHO测量的atmosFIR AFS分析仪。

   Low Level Ambient Air Platform 低水平环境空气平台
   The atmosFIR AFA model uses a uniquely designed sample gas cell of high throughput and large pathlength. This pathlength enables very low detectable limits to be made, ideal for ambient air applications in the parts per billion (ppb) range. The AFA analyser runs at ambient sample temperatures and can be used in fxed application or mobile.
   atmosFIR AFA型号采用独特设计的高通量和大光程的样气室。 该路径长度可实现非常低的可检测极限，非常适用于十亿分之几（ppb）范围内的环境空气应用。 AFA分析仪在环境样品温度下运行，可用于固定应用或移动设备。

   Figure 3 - tUnique High Pathlength Gas Cell for ppb level measurements.

图3  - 用于ppb级测量的tUnique高通道气体测量室。

     HCHO Validation  
     Accurate HCHO calibrations are important for any measurement system. Being able to generate reliable calibration standards for analyser validation is an important part of any analyser product from Protea。
     准确的HCHO校准对于任何测量系统都很重要。 能够为分析仪验证生成可靠的校准标准，是Protea的任何分析仪产品的重要组成部分。
     The beneft of atmosFIR analysers is that lack of drift in measured response to HCHO. The FTIR absorption spectrum is a function of the analyser’s well controlled parameters. This means the HCHO response is incredibly repeatable. Not only on a single instrument over time, but also instrument-to-instrument calibrations are transferable. There is no need for regular span adjustment of the analyser, only regular re-zeroing is required, which is carried out automatically on either Nitrogen or instrument air.
    atmosFIR分析仪的优势在于对HCHO的测量响应几乎没有漂移。 FTIR吸收光谱是分析仪控制良好的参数的函数。 这意味着HCHO的反应重复性很好。 不仅在一台单独仪器上，而且这台仪器到另一台仪器的校准也是可以转换的。 无需定期调整分析仪，只需要定期重新归零，这可以用氮气或仪表空气自动进行。
     Any analyser that is produced for an HCHO measurement application is calibrated in house for the gas. To this end, we have a number of reliable calibration methodologies that we use in the manufacturing process. For low level measurements of <20ppm, we have worked with gas suppliers to produce repeatable HCHO gas standards. For levels up to 100ppm, where cylinders cannot be used due to stability issues, we use permeation tubes to generate the calibration gas. Above 100ppm, Protea uses our propriety algorithms to generate synthetic data from the HITRAN atmospheric line data. These algorithms enable us to generate spectra for given instrument parameters, include background gases (such as HCHO in high H2, not just N2 background)。
   为HCHO测量应用生产的任何分析仪都在内部针对气体进行校准。 为此，我们在制造过程中使用了许多可靠的校准方法。 对于<20ppm的低水平测量，我们与标气供应商合作生产可重复的HCHO气体标准。 对于高达100ppm的水平，由于稳定性问题，不能使用气瓶，我们使用渗透管产生校准气体。 Protea使用我们的专有算法从HITRAN大气线数据生成合成数据，高于100ppm。 这些算法使我们能够为给定的仪器参数生成光谱，包括背景气体（例如高H2中的HCHO，而不仅仅是N2背景）。

atmosFIR Model  型号	Gas Cell Pathlength and Volume 气体测量室光程和体积	HCHO Lower Limit of Detection  测量甲醛探测限	Applications应用
AFS	4.2m,300ml	0.05 ppm (40°C) 0.2 ppm (180°C)	Continuous Emissions Measurements 和>0.2ppm ambient air 连续排放测量和大于0.2ppm的大气中空气测量
AFA	20.0m,4.8litres	15ppb	Very low ambient air measurements非常低的大气空气测量

Figure 4 - Measurement capabilities of atmosFIR models AFS and AFA.

图4  -  atmosFIR模型AFS和AFA的测量功能。