I am performing a reaction at 250°C at 40 bar in a slurry batch reactor with dodecane as a solvent, and I need to collect samples without sampling the catalyst.. what kind of solution
As you know filters are relatively expensive & so they will add cost to the whole process & operation. The filter will be plugged after some time by either the slurried catalyst or the slurried product assuming that one of them is separated & to be filtered. If there is an alternative to filtration, then I think it is better to be tried. Anyhow, the link below is a patent which presents filters for slurry batch reactors.
Clogging is indeed a problem using slurry-filters as Dr. Matar said above. Stopping the stirring for a short-while (1-2 minutes), i.e. letting the solid settle helps in most of the cases. Perhaps, it is a bigger problem that these filters are difficult to clean properly, i.e. you can contaminate your next run with traces of the previous catalyst. Nevertheless, to my opinion these filters are indispensable if you want to investigate kinetics (unless you have perfect homogenization with stirring during sampling). Suppliers of high pressure reactors usually have an affordable choice of filters for size and metal (the latter is preferably the same as that of your reactor made of.) Success!
We have routinely operated slurry reactors (mechanically or gas column mixed) in FT applications using particles as small as 20 microns. Sintered filter elements (i.e. Pall) are commonly used with gas blowback to minimize the impact of plugging. Low liquid flux rates are the key for this simple system. I am assuming a small reactor. the other alternative is to use a settler volume which functions in a three phase separation mode but this involves catalyst circulation with adequate baffles for solid/liquid separation. This makes kinetics based on active catalyst volume in the reactor more complicated.