For Loop Taking Too Long

I've got a sheet which I need to analyse and split into several different sheets but the raw data format leaves a lot to be desired as there are blank rows inserted randomly between rows of data. I need the 'good' data to stay in the same order so I've written a macro to sort through the data and delete any blank rows leaving the good stuff behind.

The problem is this takes ages as there can be up to 30000 rows that need to be checked and I need to do this 5-6 times a day. I just wondered weather there was a quicker way to do this? The code I've got is detailed below:



Sub Prep2()
'Delete all blank data rows
Dim Rows As Double
Dim Rownum As Double
Application.ScreenUpdating = False
Rows = Selection.SpecialCells(xlLastCell).Row

For Rownum = 2 To Rows
If Cells(Rownum, 11) "" Then GoTo NxtRownum Else

Cells(Rownum, 11).EntireRow.Delete shift:=xlUp

Rows = Rows - 1
NxtRownum:
Next Rownum
Application.ScreenUpdating = True
End Sub