Erosion of SS pipe by shredded plastic

[kimawi]

Hi All,

We are adding an extra firing pipe to an existing burner to fire waste shredded plastic ranging in size 1-35 mm. A combustion guy told us that in order to to improve burning we can introduce tangential air to the pipe at choked conditions to "stir" the plastic chunks and help them to burn as they leave the pipe. My concern is: could those plastic pieces cause erosion to the SS310 pipe at such a high velocity? Is there a threshold Rockwell number below which erosion is not an issue? I know some plastic additives can be abrasive.

Thanks

 

[cloa]

What plastic(s)?

 

[kimawi]

Well Cloa, the plastics are mainly made of the common types such as PE, PP and PVC, but I won't be surprised if there are other types with smaller quantities.

 

[SNORGY]

Most characteristic damage correlations for solids-based erosion that I am aware of employ the use of correction factors for hardness and sharpness. Since both are non-zero for plastic, one has to conclude that plastic particles can be erosive, though probably much less so than sand.

I suspect that my approach would be to evaluate a threshold erosion rate in mm/yr based on the conveyance of sand, and then change the materials properties to those representative of plastic, and then increase the solids concentration or mixture velocity or both until the same erosion rate resulted. That would then be my limiting criteria.