var
  E: OleVariant;

function DeleteList(WB: Variant; ListName: string): Boolean;
var
  i: Integer;
begin
   Result := False;
   for i := 1 to WB.Sheets.Count do
      if AnsiLowerCase(WB.Sheets.Item[i].Name) = AnsiLowerCase(ListName) then
      begin
         WB.Sheets.Item[i].Delete;
         Exit(True);
      end;
   WB := Unassigned;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
   DeleteList(E.ActiveWorkbook, 'Лист2');
end;

// Способ первый
var
  E: OleVariant;

procedure TForm1.Button1Click(Sender: TObject);
begin
   E.ActiveWorkBook.WorkSheets[1].Columns['B:B'].Select;
   E.Selection.NumberFormat := '@';
end;

// Способ второй
var
  E: OleVariant;

procedure TForm1.Button1Click(Sender: TObject);
begin
   E.ActiveWorkBook.WorkSheets[1].Columns['B:B'].NumberFormat := '@';
end;