PAHs

The use of high speed GC coupled with filter tape sampling and thermal desorption has been applied to the online assessment of PAHs in a combustion process.

Gas and particulate material are sampled directly from the emission stack using a null-type probe. A

Figure 7 Overview of the sampling and analysis system for online measurement of PAHs in a combustion process. (Reproduced with permission from Munchmeyer etal., 1996.)

dilution method is used to cool the gas stream to below 50°C so that condensation of the PAHs occurs on particulates in the gas stream. These particulates are then retained on a glassfibre filter. Figure 7 shows the instrumental layout used for this work.

Once sampling is complete the PAHs are desorbed at 300°C by contact with a heated piston. The sample enters a short (1.6 m) metal capillary column, resis-tively heated, which allows for rapid cycling. The sample is detected using mass spectrometry. Complete separation of all PAH isomers is not achieved, although overlapping peaks of substances with different mass spectra can be resolved by correlation software. With a sample volume of 100 L the LOD values were found to be below the emission limits for carcinogenic compounds such as benzo[tf]pyrene.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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