Traditional gas analysis methods are in general off-line methods. Off-line methods provide process information reliably, but they take much time to complete. Some processes need high sampling rate and off-line methods are not suitable for these purposes. For these situations, VTT has developed and tested on-line measurement applications with high sampling rate and reliable results.
VTT has developed and patented dilution sampling methods for processes with high concentration of condensable components. From this kind of dirty environment, it is difficult to gain reliable and representative samples without sample dilution steps. Dilution sampling is a computer programmed method that produces diluted sample for analysis and then calculates with the dilution coefficient the true component concentrations accurately and reliably. Dilution sampling equipment can be joined with needed analytical methods, such as, GC, ICP or FT-IR. The dilution method has been tested extensively in biomass gasification environment for tar and particle analysis.
On-line analysis methods
In well-established processes and in normal operation conditions, the sample analysis frequency is not a crucial factor. However, if real time process tacking is needed, the traditional off-line methods are not feasible option. With off-line methods, the sample analysis rate is given in hours, whereas on-line methods can acquire information in minutes. This enables the process tracking almost in real time, which is a great tool in process development environment. In addition, the on-line methods operating principles are simple compared to off-line methods and it is much less work intensive option for process tracking. With on-line methods, it is possible to create a set-up of different analytical methods and connect the analysis equipment to automation system.