Welcome to the Gas Analysis Wiki.
This site is for sharing information about the present status of gas sampling and analysis methods in addition to recent exchange in the Gas Analysis Working Group.
This Wiki was initiated to support analytical work in thermochemical conversion processes where gas analysis is particularly difficult due to high gas temperature, particles in the gas as well as condensible compounds like water vapour or 'tar'. There will be room for techniques and recent approaches unsed in other gas production, gas cleaning, pipeline injection or gas synthesis processes e.g. from fermentation. We will get started with some techniques used for tar analysis which is a challenge and an obstacle in gasification of biomass. After a discussion of the method relevant literature sources are presented. The information about different techniques shall be supplemented by fotographs and videos or by more detailed descriptions.
The term 'tar' represents semi-liquid mixtures of organic compounds that originated in thermal conversion processes and then condensed while cooling down the gas phase. Tars have a yellowish or brownish to black appearance and a pungent smell. A number of tar constituents is harmful to health or environment. Tar is seen problematic in a number of processes. In gasification, pyrolysis and even combustion processes tar occurs, is unwanted and shall be removed with the lowest possible effort. A scientific aim is to identify parameters for characterizing 'tar' in order to run the conversion process still efficiently, meaning at desirable gas compositions as output and low on tar. This section gives some information and relevant sources of information on common techniques applied to tar sampling and analysis. Furthermore approaches to analyze 'tar' on-line or to monitor a 'tar-content' are presented and described.