Multiple Instances of Batch Processing

I plan to do a lot of geometric terrain corrections, >1000, with ~50 different DEMs (~20 with one DEM, another 20 with a different DEM, etc.). I would like to use the graph tool, set up a few of the batches that I need run, and then run them simultaneously.

Can SNAP run multiple different batch processes simultaneously? Will running multiple batches at the same time cause problems?

No, and for performance reasons (file I/O) only one graph should be in execution in any one time. If you have a cluster you can run one graph per physical machine simultaneously.