Instruments Intro

Stack Emission Sampling : Side sampling

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Side samplingIntroduction

The derived sampling This isokinetic sampling technique is becoming more and more diffused in the European market thanks to the increasing application of methods such as :

EN14385 for heavy metalsEN13211 for MercuryEN1911 for Chloridric acidEN14791 for SOx

What is the derived samplingWhen applying the derived sampling, or side sampling, an aliquote of the main isokinetic flow is sampled by a second constant flow sampler operating a much lower flowrate.Of course, the main isokinetic flow must take in account the second sampler and this value must be lowered of the amount sampled by the derived sampler.

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Side samplingWhat is it

The derived sampling Keys :

1Nozzle5Valve9Absorber2Probe6By-pass valve9aSafety bottle (trap)3Filter (either behind or in front of the probe)7Pump10Gas flow meter4Dryer cartridge8Gas volume meter*11Temperature andPressure measure

Scheme from the EN14385*EN14385 Ch. 5.1.2.7 Gas Volume Metering Two gas volume measuring methods may be used: 1) Gas Flow Measurement (Method 1) 2) Gas Flow Measurement (Method 2) Both methods are described in EN13284-1. Method 2 is more accurate than method 1

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Side samplingWhat is it

The derived sampling The derived sampling, or side sampling, offers different advantages.1) From the technical point of view, sampling an aliquote from the main isokinetic sampling, at lower flowrate, grants a higher contact time between the sample and the adsorbing solution resulting in a lower loss of the analyte, increasing the accuracy of the determination.

2) Since the volume of the adopted impingers, and adsorbing solution, is generally lower compared to the usual impinger train, like for the EPA methods, the probability to reach the analytical lower detection limit is higher.

3) Particulate matter and Micropollutants sampling takes place simultaneously, reducing the required time to complete the operations.

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Side samplingRealization

The derived sampling The number of side sampling lines may vary from one up to four.Increasing the number of derived lines increases the complexity and difficulty to manage the operation but give the advantage to sample many parameters simultaneously.

Single derivationQuad derivationIn the past years, the derived lines werent so diffused and manufacturers built them in the easiest way as possible (= not the best solution for users).Full glass/quartz filterholders with derivation/s realized directly on tail body. This solution was quite expensive, easy to break and forcing the users to buy different sampling filterhoders.Dado lab realized the side sampling devices in titanium and they can be added to the filterholder when needed.

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Side samplingDado lab solution

The derived sampling Realization of the derived lines - the French job :

The French market is the most difficult to satisfy from the side sampling point of view. French laboratories always build isokinetic line + 4 derivations to sample simultaneously PM, heavy metals, mercury, acids and SOx.Dado lab realized special supports to hold two Athermal boxes equipped with two trains of three impingers each. Temperature is measured directly in the derivations device.-

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Side samplingDado lab solution

The derived sampling Construction of a derived line

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Side samplingIntroduction

The derived sampling Impingers train

Main isokinetic lineSide sampling line

The double line can be realized inside the Athermal box, which grants a superior protection to the glass materials.

The box is then connected to the heated hub without screws, a very practical solution when we have to work on platforms with protection gloves.

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New solutionsIntroduction

Glass or Polycarbonate impingersThe side sampling stream has been always realized with glass impingers.Glass is an excellent material because of its low interaction with the samples but is very fragile and can represent a risk of injury for the technicians. To reduce injuries risk and loss of the sample, Dado lab realized the impingers in polycarbonate :

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New solutionsIntroduction

Polycarbonate impingers sampling train :Although this material is not yet considered in any sampling standard, it shows a chemical resistance similar to PTFE and PVDF.

For example, they can be used with HNO3 up to 30% concentration, more than the requested concentration used for heavy metals extraction.

Not suitable when using organic solvent for extraction (eg for PAH or PCDD/PCDF)

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New solutionsIntroduction

Polycarbonate impingers - Advantages

Superior safetyHigher tightnessPTFE connectionsInterchangeable parts

tightness

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Side SamplingIntroduction

The derived sampling How to setup the Dado lab sampling line with derivation :

- Close the intercepting valve* to avoid liquid suction from the isokinetic sampler

Set the flowrate, Nl/Min, on the derived sampling pump**

On the ST5, select the sidestream menu (F.1), program the side sampling flowrate (F.2) and activate the option (press F1). The ST5 will consider the side florate and calculate the ratio.* its strongly suggested to place an intercepting valve before the derived impinger train to allow to set derived flowrate without having to worry about pressure balance with the main isokinetic flow. ** The QB1 series have a built-in flow loop which allow to set a flow with the sampling line closed.

F.2F.3F.1

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Side SamplingIntroduction

The derived sampling - Slowly open the intercepting valve in order to balance the different pressures between the isokinetic and side sampling line and avoid the adsorption solution to be sucked by the isokinetic sampler.

- The ST5 will take in account the second flowrate and will adjust the isokinetic condition accordingly. - In the Sidestream menu, the ratio between the isokinetic and derived flow will be calculated. The EN standards asks for a constant ratio between isokinetic and derived flow.- Technically, the side sampler flowrate should be adjusted continuously (every 5 minutes at least) to meet the requirements of the methods.

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Automatic Derived SamplerIntroduction

ADS-1

The first fully automatic side sampler

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ST5Introduction

ST5 and ST5 Evo

With the ST5 and ST5 Evo, Dado lab pushed the automatism for the isokinetic sampling to a higher level, granting the fastest response to isokinetism along high quality/traceable data

Automatic Derived SamplerWhat is still missing on the market is the automatization of the side sampling operation. A request coming mainly for the quality of the data since, actually, the operation of the side sampler is carried out with manual data recording and, thus, affected by errors.Dado lab is the first company introducing on the market a solution for the fully automatic operation of the side sampling.

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Automatic Derived SamplerADS-1

ADS-1 Single channel automatic derived samplerpractically replaces the actual constant flow sampler.

It will interface itself with the isokinetic sampler which will manage the information and continuously set the flowrate in order to keep the ratio constant.

Its only necessary to set the starting derived flowrate accordingly to the adopted adsorbing train, since it may vary depending on the application, and then the ST5s GPM routine will constantly monitor and set the flowrate on the ADS.

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Automatic Derived SamplerOperation

How it works...Set up the sampling line. The ST5 and ADS must be turned on.

Program the isokinetic sampling on the ST5.

Press to go to the side stream sampling menu. Enter the side stream flowrate value and activate the side sampling (F1). The ST5 will communicate the side sampling flowrate to the ADS unit.

The ST5 starts its own isokinetic operation, without starting to control the ADS until the stable isokinetic condition is reached (-5%