Tar analysis is particularly relevant in biomass related thermochemical processes. VTT has extensive background knowledge especially in the development of gasification processes and their analytical methods. For tar analyses we use methods derived from CEN/TS 15439-specifications.
Sampling and analysis of tar and particles in biomass produced gases - Technical Report
Verenum, J. G.; Ventress, L. (Casella Group); Knoef, H. (Biomass Technology Group, BTG); Zielke, U. & Hansen, L. (Danish Technological Institute, DTI); van de Kamp, W., de Wild P., Coda, B., van Paasen, S., Kiel, J. (Energy research Centre of the Netherlands, ECN); Sjöström, K. & Liliedahl, T. (Royal Institute of Technology, KTH); Unger, Ch. (Fraunhofer Institute for Environmental, Safety, and Energy Technology, UMSICHT); Neeft, J. (SenterNovem); Suomalainen, M. & Simell, P. (VTT)
Tar in gasification gas
Tar is a complex mixture of various kinds of organic components, that are released in biomass thermochemical conversion processes. Tar has many traditional uses, but in process equipment tar is undesired compound as it creates problems, such as system malfunction and clogging. Tars are created in various kinds of processes from biomass energy production to gasification applications.
There is no definite description for tar as a compound and, therefore it is reasonable divide tars into classes. One classification system could be that tars are divided by their formation temperature as low and high process temperature tars. In VTT analyses, tar contain hydrocarbons from benzene (C6H6, 78 g/mol) to heavier components up to 300 g/mol. Over 300 g/mol compounds can be determined as a fraction from the total tar content.
The tar formation is dependent upon many aspects, such as, biomass fuel composition and process parameters. Primarily it is best to avoid the formation of tars, but in many processes it is unavoidable (well operating gasification process produces less than 200 mg/m3n of tar). Therefore, tars have to be separated, cracked in high temperature or reformed in the presence of a catalyst.
Tar sample analysis
VTT well established methods for analysis of several different gas components. About tar analysis, our competence is built through decades of work with gasification applications. The measurement of tars from a gas stream provide valuable information from the operation of the process equipment and how process parameters should be adjusted in order to achieve best possible outcome. VTT has verified methods for the analysis of water, light hydrocarbons C1 - C7, benzene, toluene and other tar compounds (molecular mass 78 - 300 g/mol).
Sample gathering is one of the most important aspects of the analysis procedure. VTT has developed analysis methods along the design and implementation of laboratory and pilot scale experimental units. Therefore, we have strong knowledge about the whole scheme of thermochemical conversions processes and related analytical methods. In addition to analytical methods, VTT has special tar sample gathering equipment that can be fitted in many different processes. One example could be the absorption of condensable organic compound to a solvent, which enables reliable analysis regardless of solid particulates and water.
Tar sample gathering equipment
Analysis results for process development and expert guidance
After sample analysis, the analytical results are presented in a clear way that can be easily used for process development (example of results summary below). In addition to analytical services, we can provide an expert proposal in order to apply improvement to our customer’s processes.
An example of tar analysis results summary