EPA METHOD 25-总气态非甲烷有机物(NMOC)(以碳计)排放量的测定(中文翻译)

更新时间:2023-07-21 01:27:51 阅读: 评论:0

METHOD 25 - DETERMINATION OF TOTAL GASEOUS
NONMETHANE ORGANIC EMISSIONS AS CARBON
五、方法25-总气态非甲烷有机物(以碳计)排放量的测定
1.0 Scope and Application.范围和应用
1.1 Analytes.分析物质
1.2 Applicability. 1.2适用性。
1.2.1 This method is applicable for the determination of volatile organic compounds (VOC) (measured as total gaous nonmethane organics (TGNMO) and reported as carbon) in stationary source emissions. This method is not applicable for the determination of organic particulate matter.
1.2.1该方法适用于测定固定排放源中的挥发性有机化合物(VOC)(以气态非甲烷有机物总量(TGNMO)测量,单位以碳计)。该方法不适用于有机颗粒物的测定。
1.2.2 This method is not the only method that applies to the measurement of VOC. Costs, logistics, and other practicalities of source testing may make other test methods more desirable for measuring VOC contents of certain effluent streams. Proper judgment is required in determining the most applicable VOC test method. For example, depending upon the molecular composition of the organics in the effluent stream, a totally automated micontinuous nonmethane organics (NMO) analyzer interfaced directly to the source may yield accurate results. This approach has the advantage of providing emission data micontinuously over an extended time period.
1.2.2该方法并非唯一适用于VOC测量的方法。成本,物流和排放源测试的其他实用性可能使其他测试方法更适合于测量某些排放气体的VOC含量。在确定最适用的VOC测试方法时,需要做出正确的判断。例如,根据排放气体中有机物的分子组成,直接连接到排放源的全自动半连续非甲烷有机物(NMO)分析仪可能会产生准确的结果。这种方法的优点是可以在一定时间段内半连续地提供排放数据。
1.2.3 Direct measurement of an effluent with a flame ionization detector (FID) analyzer may be appr
来球
opriate with prior characterization of the gas stream and knowledge that the detector responds predictably to the organic compounds in the stream. If prent, methane (CH4) will, of cour, also be measured. The FID can be ud under any of the following limited conditions: (1) where only one compound is known to exist; (2) when the organic compounds consist of only hydrogen and carbon; (3) where the relative percentages of the compounds are known or can be determined, and the FID respons to the compounds are known; (4) where a consistent mixture of the compounds exists before and after emission control and only the relative concentrations are to be assd; or (5) where the FID can be calibrated against mass standards of the compounds emitted (solvent emissions, for example).
1.2.3使用火焰离子化检测器(FID)分析仪直接测量排放可能需要事先对废气进行表征,并了解检测器可预测地响应流中的有机化合物。如果甲烷(CH4)存在的话,当然也会被测量。FID可在以下任何限制条件下使用:(1)仅已知存在一种化合物的情况;(2)当有机化合物仅由氢和碳组成时;(3)化合物的相对百分比已知或可以确定,并且对化合物的FID响应已知;(4)在排放控制前后存在一致的化合物混合物的情况,仅应评估相对浓度;或(5)可以根据所排放化合物的质量标准(例如,溶剂排放)对FID进行校准。
1.2.4 Another example of the u of a direct FID is as a screening method. If there is enough informa
tion available to provide a rough estimate of the analyzer accuracy, the FID analyzer can be ud to determine the VOC content of an uncharacterized gas stream. With a sufficient buffer to account for possible inaccuracies, the direct FID can be a uful tool to obtain the desired results without costly exact determination.
1.2.4使用直接FID的另一个示例是作为筛选方法。如果有足够的信息来提供对分析仪精度的粗略估计,则可以使用FID分析仪确定未表征气流的VOC含量。有了足够的缓冲区来解决可能的不准确性,直接FID可以成为获得所需结果的有用工具,而无需进行昂贵的精确确定。
1.2.5 In situations where a qualitative/quantitative analysis of an effluent stream is desired or required, a gas chromatographic FID system may apply. However, for sources emitting numerous organics, the time and expen of this approach will be formidable.
1.2.5在需要或需要对排放气体进行定性/定量分析的情况下,可以使用气相色谱FID系统。但是,对于排放大量有机物的排放源来说,这种方法的时间和费用将是巨大的。
2.0 Summary of Method. 2.0方法摘要。
2.1 An emission sample is withdrawn from the stack at a constant rate through a heated filter and a chilled condensate trap by means of an evacuated sample tank. After sampling is
completed, the TGNMO are determined by independently analyzing the condensate trap and sample tank fractions and combining the analytical results. The organic content of the condensate trap fraction is determined by oxidizing the NMO to carbon dioxide (CO2) and quantitatively collecting in the effluent in an evacuated vesl; then a portion of the CO2 is reduced to CH4 and measured by an FID.
2.1排放样品通过加热的过滤器和冷却的冷凝水收集器以恒定的速率从烟囱中抽出至排空的样品罐中。采样完成后,通过独立分析凝结水阱和样品罐中的组分,并结合分析结果来确定TGNMO。冷凝水捕集组分的有机物含量通过将NMO氧化为二氧化碳(CO2)并定量收集在抽空容器中,然后将一部分CO2还原为CH4并通过FID进行测量。郭跳跳
长与短
The organic content of the sample tank fraction is measured by injecting a portion of the sample into a gas chromatographic column to parate the NMO from carbon monoxide (CO), CO2, and CH4; the NMO are oxidized to CO2, reduced to CH4, and measured by an FID. In this manner, the variable respon of the FID associated with different types of organics is eliminated.
通过将一部分样品注入气相色谱柱以将NMO与一氧化碳(CO),CO2和CH4分离,来测量样品罐馏分中的有机物含量。NMO被氧化成CO2,还原成CH4,并通过FID进行测量。以这种方式,消除了与不同类型的有机物相关联的FID的可变响应。
3.0 Definitions. [Rerved] 3.0定义。[保留]
4.0 Interferences. 4.0干扰。
4.1 Carbon Dioxide and Water Vapor. When carbon dioxide (CO2) and water vapor are prent together in the stack, they can produce a positive bias in the sample. The magnitude of the bias depends on the concentrations of CO2 and water vapor. As a guideline, multiply the CO2 concentration, expresd as volume percent, times the water vapor concentration. If this product does not exceed 100, the bias can be considered insignificant. For example, the bias is not significant for a source having 10 percent CO2 and 10 percent water vapor, but it might be significant for a source having 10 percent CO2 and 20 percent water vapor.
追月亮
4.1二氧化碳和水蒸气。当烟囱中同时存在二氧化碳和水蒸气时,它们会在样品中产生正偏压。偏差的大小取决于CO2和水蒸气的浓度。原则上,将以体积百分比表示的CO2浓度乘以水蒸气浓度。如果该乘积不超过100,则可以认为偏差不明显。例如,对于含10%CO2和10%水蒸气的源,该偏差不明显,但对于含10%CO2和20%水蒸气的源,该偏差可能较大。
4.2. Particulate Matter. Collection of organic particulate matter in the condensate trap would produce a positive bias. A filter is included in the sampling equipment to minimize this bias.
4.2。颗粒物。在凝结水阱中收集有机颗粒物质会产生正偏差。采样设备中包括一个过滤器,以最大程度地减小此偏差。
5.0 Safety. 5.0安全。
5.1 Disclaimer. This method may involve hazardous materials, operations, and equipment. This test method may not address all of the safety problems associated with its u. It is the responsibility of the ur of this test method to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to performing this test method.
5.1免责声明。该方法可能涉及危险材料,操作和设备。此测试方法可能无法解决与
其使用相关的所有安全问题。使用此测试方法的用户有责任建立适当的安全和健康惯例,并在执行此测试方法之前确定法规限制的适用性。
6.0 Equipment and Supplies. 6.0设备和用品。
6.1 Sample Collection. The sampling system consists of a heated probe, heated filter, condensate trap, flow control system, and sample tank (e Figure 25-1). The TGNMO sampling equipment can be constructed from commercially available components and components fabricated in a machine sh
op. The following equipment is required:
6.1样品采集。采样系统由加热探头,加热过滤器,冷凝水收集器,流量控制系统和样
品罐组成(见图25-1)。TGNMO采样设备可以由市售组件和在机械车间中制造的组件
构成。需要以下设备:
6.1.1 Heated Probe. 6.4-mm (¼-in.) OD stainless steel tubing with a heating system capable
of maintaining a gas temperature at the exit end of at least 129°C (265°F).
6.1.1加热探针。外径为6.4毫米(1/4英寸)的不锈钢管,带有加热系统,能够将出口端的气体温度保持至少129°C(265°F)。
The probe shall be equipped with a temperature nsor at the exit end to monitor the gas temperature. A suitable probe is shown in Figure 25-1. The nozzle is an elbow fitting attached to the front end of the probe while the temperature nsor is inrted in the side arm of a tee fitting attached to the rear of the probe. The probe is wrapped with a suitable length of high temperature heating tape, and then covered with two layers of glass cloth insulation and one layer of aluminum foil or an equivalent wrapping.
梁启超家书探头的前端应装有温度传感器,以监测气体温度。一个合适的探头如图25-1所示。喷嘴是安装在探头前端的弯头配件,而温度传感器插入安装在探头后部的三通配件的侧臂中。用合适长度的高温加热带包裹探头,然后用两层玻璃布绝缘层和一层铝箔或等效的包裹物覆盖。
NOTE: If it is not possible to u a heating system for safety reasons, an unheated system with an in-stack filter is a suitable alternative.
注意:如果出于安全原因无法使用加热系统,则在烟道中加过滤器的不加热系统是合适的选择。
6.1.2 Filter Holder. 25-mm (15/16-in.) ID Gelman filter holder with 303 stainless steel body and 316 stainless steel support screen with the Viton O-ring replaced by a Teflon O-ring.
6.1.2过滤器支架。25毫米(15/16英寸)内径的盖尔曼过滤器支架,带有303不锈钢主体和316不锈钢支撑筛网,其中的Viton O形圈被特氟龙O形圈代替。
香柠檬6.1.3 Filter Heating System.
6.1.3过滤器加热系统。
6.1.3.1 A metal box consisting of an inner and an outer shell parated by insulating material with a
苹果英语heating element in the inner shell capable of maintaining a gas temperature at the filter of 121 ± 3 °C (250 ± 5 °F). The heating box shall include temperature nsors to monitor the gas temperature immediately upstream and immediately downstream of the filter.
6.1.3.1一个金属箱,该金属箱由一个内壳和一个外壳组成,这些内壳和一个外壳之间由绝缘材料隔开,内壳中具有一个加热元件,能够在过滤器上保持气体温度为121±3°C (250±5°F)。加热箱应包括温度传感器,以监测紧接过滤器上游和下游的气体温度。
6.1.3.2 A suitable heating box is shown in Figure 25-2. The outer shell is a metal box that measures 102 mm x 280 mm x 292 mm (4 in. x 11 in. x 11 ½ in.), while the inner shell is a metal box measuring 76 mm x 229 mm x 241 mm (3 in. x 9 in. x 9 ½ in.). The inner box is supported by 13-mm (½-in.) phenolic rods. The void space between the boxes is filled with ceramic fiber insulation which is aled in place by means of a silicon rubber bead around the upper sides of the box. A removable lid made in a similar manner, with a 25-mm (1-in.) gap between the parts is ud to cover the heating chamber. The inner box is heated with a 250-watt cartridge heater, shielded by a stainless steel shroud.
游库6
6.1.3.2一个合适的加热箱如图25-2所示。外壳是尺寸为102 mm x 280 mm x 292 mm(4英寸x 11英寸
x 11½英寸)的金属盒,而内壳是尺寸为76 mm x 229 mm x 241 mm(3英寸x 9英寸x 9½英寸)。内盒由13毫米(1/2英寸)酚醛棒支撑。盒子之间的空隙填充有陶瓷纤维绝缘材料,该绝缘材料通过围绕盒子上侧的硅橡胶珠密封在适当的位置。以类似的方式制成的可移动盖子用于在加热部件之间形成25毫米(1英寸)的间隙。内盒用250瓦的筒式加热器加热,并用不锈钢罩屏蔽。

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