split a datatable based on number of rows

                
                        DataTable[] splittedtables = tbl.AsEnumerable()
    .Select((row, index) => new { row, index })
    .GroupBy(x => x.index / 12)  // integer division, the fractional part is truncated
    .Select(g => g.Select(x => x.row).CopyToDataTable())
    .ToArray();