var bsPDF := TBlobStream.Create(fldBlob);
  try
    ImageEnView1.PdfViewer.Enabled := True;
    ImageEnView1.PdfViewer.LoadFromStream(bsPDF);
  finally
    bsPDF.Free;
  end;

var bstream: TStream;
begin
       
  bstream := dset.CreateBlobStream(fld, bmRead);
  
  try
    imageEnView.PdfViewer.Enabled := True;
    imageEnView.PdfViewer.LoadFromStream(bstream);
  finally
    bstream.Free;
  end;
end;