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4.6. Sorbent Traps (40 CFR Part 75 Continuous Emission Monitoring, App. K) 4.6.3. Ohio Lumex and Apex Instruments Ohio Lumex and Apex Instruments have teamed up to provide a sorbent trap system. The XC-6000EPC MercSampler, provided by Apex Instruments, consists of the following: probe, paired sorbent traps, automated data acquisition and handling system, moisture removal components, sample pump, dry gas meter and heated umbilical line, Figure 4-37. Sorbent traps, and sorbent analysis instrumentation were provided by Ohio Lumex. 4.6.3.1. Apex Instruments Sampling System. The monitoring system samples stack gas at a rate proportional to the stack gas volumetric flow rate. Sampling is a batch process. Mercury mass emissions per hour during the sampling period are calculated by using stack gas flow rate measured by a certified flow monitor and correcting it to standard conditions (pressure and temperature). Each system requires the use of paired sorbent traps. For each pair of sorbent traps analyzed, the average of the two Hg concentrations are used for reporting purposes under §75.84. Each sorbent trap contains a main section, backup section and third section to allow spiking with a calibration gas of known Hg concentration. A certified flow monitoring system and correction for stack gas moisture content are required. The automated data acquisition and handling system ensures the sampling rate is proportional to the stack gas volumetric flow rate. After each sample collection period, the mass of Hg adsorbed in each sorbent trap is determined according to the applicable procedures in appendix K to part 75. The sorbent media used to absorb Hg are configured in a trap using three distinct and identical sections, which could be analyzed separately. Section 1 - Primary capture of gaseous Mercury Section 2 - Determination of breakthrough Section 3 - Spiked with known amount of gaseous Hg prior to sampling for determining recovery efficiency The sorbent media can be any collection material capable of capturing and recovering all gaseous forms of Hg for subsequent analysis. Examples include carbon or a chemically treated filter. Selection of the sorbent media is based on the material’s ability to achieve the performance criteria contained in Section 8 of Appendix K. In addition, selection is based on the sorbent vapor-phase Hg capture efficiency for the emissions matrix and the expected sampling duration at the test site. Paired sorbent traps are supported on a probe(s) and inserted directly into the flue gas stream. Each sorbent trap is mounted for gas samples to enter the trap directly. This mount can be within the probe or at the entrance. Each probe and/or sorbent trap assembly must be heated to a temperature sufficient to prevent liquid condensation in the sorbent traps. The probes use a calibrated thermocouple to monitor the stack temperature. A single probe capable of operating the paired sorbent traps may be used. Alternatively, individual probe/sorbent trap assemblies may be used, provided that the individual sorbent traps are co-located. A moisture removal device or system, suitable for continuous duty (e.g. Peltier cooler), is included to remove water vapor from the gas stream prior to entering the dry gas meter. A known mass of gaseous Hg is spiked onto Section 3 of each sorbent trap prior to sampling. A practical system, capable of delivering almost any mass required, makes use of NIST-certified or NIST-traceable Mercury salt solutions (e.g., Hg(NO3)2). Any analytical system capable of quantitatively recovering and quantifying total gaseous Hg from sorbent media is acceptable provided that the analysis can meet the performance criteria in Section 8 of this procedure. Candidate analytical techniques include ultraviolet atomic fluorescence (UVAF); ultraviolet atomic absorption (UVAA), with and without gold trapping; and in situ X-ray fluorescence (XRF) analysis. 4.6.3.2. Ohio Lumex Sorbent Traps. Sorbent traps, provided by Ohio Lumex for the Armstrong test, are presented in Figure 4-38. Ohio Lumex sorbent trap specifications and characteristics: Spiked/not spiked 3-section sorbent traps are available in sizes 6 mm and 10 mm OD; 4-section traps are available for Hg specialization Iodinated, acid washed coconut shell charcoal. 150 mg and 1g loading on small/large trap section. Low mercury background levels: less then 2 ng per section Easy to remove and easy to set for “leak check” cap plugs Extra thick glass for trap rigidity Customized spiking level for the 3rd section: 50 to 200,000 ng Long term storage stability: 1year Sampling duration: up to 2 weeks High-capacity mercury loading: up to 200,000 ng per section In-house analysis with short turnaround time 4.6.3.3. Trap Analysis Procedure. RA-915+ analyzer with RP-M324 attachment, Figure 4-39, is designed for field on-site or laboratory testing of sorbent trap tubes for Sorbent Trap Monitoring of Hg emissions from coal fired power plants. U.S. EPA validated thermal decomposition is referenced in appendices K part 75 of the Clean Air Mercury Rule. The AA technology is used for no sample preparation analysis. Analysis time is less than two minutes per sample. No liquid chemicals or gas are required, and no chemical waste is generated. RA-915+ with RP-M324 A sorbent trap tube is cut and sorbent is transferred onto a quartz ladle. The ladle is inserted into the analyzer thermo catalytic conversion chamber heated to 800°C wherein mercury is converted from a bound state to the atomic state by thermal decomposition in a two-section furnace. This approach requires no pre-concentration on gold, eliminating the associated problems. The use of multi-path cell combined with “dry” converter provides highest sensitivity with no interferences from the sample matrix. Mercury measurements take place in the heated cell zone of converter directly coupled to spectrometer. High temperature (800C) and short residence time prevents Hg atoms from recombining with any “active” species generated due to high temperature decomposition of sample matrix. An external pump is used to draw ambient air and purify it for combustion. No cylinders of oxidizer or compressed gases are required |
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wypward(金币+1):谢谢参与 2010-10-20 10:37:19
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46。吸着剂陷阱(40 CFR部分75连续排放监测,应用程序。凯西) 4.6.3。俄亥俄州Lumex和顶端工具 俄亥俄州Lumex和顶端工具已合作提供吸附剂陷阱系统。MercSampler所提供的XC-6000EPC顶端工具,包括下列事项:、探测器、吸着剂的陷阱,自动数据采集与处理系统的组成、样品、水分去除燃气计量表和泵、干燥,加热4-37脐线。吸着剂和分析仪器是由吸着剂Lumex俄亥俄州。 4.6.3.1。顶端仪器采样系统。烟道气样品的监控系统速率成正比的烟气体积流量。采样是批量生产。汞排放每小时在大规模的采样周期计算了烟气流量测量由有资格证书的流量监测和修改标准的条件(压力和温度)。每个系统采用配对的吸着剂的陷阱。为每一对吸着剂圈闭的原因进行了分析,提出了两种汞浓度平均用于报告目的下75.84关联。 每一个主要部分包含吸附剂陷阱,备份和第三段允许扣球和校正气体浓度的已知汞。注册流量监测系统和修正烟气含水率是必需的。 自动数据采集与处理系统确保采样率是成正比的烟气体积流量。之后,每个采样周期,大众的汞吸附在每个吸着剂陷阱是根据适用的程序在附录K部分75。 媒体的吸着剂用于吸收汞配置在陷阱里使用三种截然不同的相同的部分,可单独分析。 第一节-原发性捕捉气态的水银 第二节-火焰原子吸收光谱法测定的突破 第三节-极速与已知数量的气态汞的采样测定前采收率 该媒体可以是任何收集资料的采集和恢复所有的气态形式的汞为后续的分析。例子包括碳或化学处理的过滤器。选择的媒介是基于物质的能力来实现绩效准则中包含的附件8节.此外,选择是基于对汞效率的气相捕捉排放矩阵和预期的采样时间试验基地。成双成对的吸着剂圈闭支持一个探针插入(s),直接进入了烟气流。 每个吸着剂陷阱安装燃气样品直接进入了陷阱。这可以在探测器上或在大门口。每个探头和/或吸附剂疏水阀总成必须被加热到足够的温度,防止液体凝结在吸着剂的陷阱。用探针的校准热电偶监控堆栈的温度。一个单个探头能操作配对的吸着剂陷阱可以使用。另外,单个探头/吸着剂疏水阀总成可以使用,但个别的吸着剂陷阱是一个地区。 一排潮装置或系统,适用于连续工作(例如。珀尔贴冷却器),包括去除水气气体流进入干燥前燃气计量表。 已知数量的气态汞是尖到第三节的前吸附剂陷阱采样。一个实用的系统,能提供任何质量要求,利用NIST-certified盐溶液或NIST-traceable水银(例如,汞硝态氮(2)。 有能力的定量分析系统恢复和量化总气态媒体是可接受的汞自吸着剂的性能指标的分析,可以满足在第8行这种手术。候选人分析技术,包括紫外线原子荧光法);(UVAF紫外线原子吸收(UVAA),并没有黄金捕获、原位x射线荧光光谱法分析检测(。 4.6.3.2。俄亥俄州Lumex吸着剂的陷阱。吸着剂的陷阱,由俄亥俄Lumex为阿姆斯特朗试验,给出了4-38人物。 俄亥俄州Lumex规格及特点:吸附剂陷阱, 带刺的/不带刺的3-section吸着剂圈闭的尺寸6毫米和10毫米;4-section外径陷阱可供汞专业化 Iodinated、酸性清洗椰子壳木炭。150毫克及相关装上小/大陷阱区。 低汞的背景值:不到2 ng /部分 容易拆卸和容易设定为“泄漏”帽插头 额外的厚玻璃为陷阱的刚性 定制为第三段扣球水平:50到20万 长期贮存稳定性:具有一年以上 采样周期:2周 大容量的水银加载:200000 ng /部分 内部的分析与短的转机时间 4.6.3.3。陷阱分析程序。 RA-915 +分析仪和RP-M324附件,图4-39,是专为野外实地或实验室试验的吸着剂陷阱管汞排放监测吸附剂陷阱从燃煤发电厂。美国环保署确认热分解参考在附录K部分的75空气清净。机管局技术被用于任何样品制备技术分析。 分析时间少于两分钟的样品。任何液体或气体所需的化学物质,任何化学废物产生。 与RP-M324 RA-915 + 管子切割吸附剂陷阱,转移到一个石英相中勺子。插入了钢包热分析仪的催化转化室加热到800度,其中汞转化为界,从国家的原子状态中热分解过程划分为炉。 该方法不需要对各种黄金,消除相关的问题。利用多路细胞结合“干”变换器敏感度最高无干扰从样品矩阵。汞测量发生激烈的细胞区转炉直读光谱仪直接连接。高温(800C)和较短的停留时间防止汞原子与任何“积极”车流物种由于高温分解生成矩阵的样品。外部泵是周围的空气和净化它燃烧。无油缸氧化物或压缩气体是必需的 |
2楼2010-10-19 18:22:37
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3楼2010-10-21 14:55:33