Does HDR Expose support batch operation when I need to merge multiple bracketed image sequences into HDR?

Yes. HDR Expose implements HDR batch merge operation.

If you shoot many bracketed sequences in one day you can conveniently merge them into any HDR format file for later processing. In the "Merge to HDR" dialog (accessible from the File menu), choose the "Batch merge" tab. Then press the "+" button. In this window you have the option to specify the number of bracketed shots in each individual HDR sequence and a folder where the source files for the sequences are located. Note that the batch operation only works on bracketed sequences with the same number of shots within one folder. If you have images with varying number of shots, you have to place them in separate folders in order to perform the HDR batch merge on them.