C#处理Excel表格速度很慢

工程需要，做了一个处理重复表号的一个表格。
表格里第一列是表号；第一行是标题头；从第二行开始是12位数字的表号。这个小程序的用途就是将相同表号的这一行删除掉。比如第二行取表号，然后与第3行，第N行比较，遇到相同的，就把这一行删掉；依次做下去，最后保存的表格每行的表号都是唯一的。
做的这个小程序，处理速度极慢，1137行的数据，按道理说，应该很快。我算了下时间，10分钟才处理300来个。是两层循环，循环是慢点，但我觉得不至于这么慢。
因为对C#了解很少，找不到问题，请朋友们指点下，谢了。
下面上截图和代码：

 private void OpenExcel(string strFileName)

        {

            object missing = System.Reflection.Missing.Value;

            int meterColumn = 0;

            int rowEffictive = 0;

            string[] meterNo = new string[150000];

            try

            {

                string workTmp = strFileName;

                Range range = null;

                objExcelApp = new ApplicationClass();

                objExcelWorkBooks = objExcelApp.Workbooks;

                objExcelWorkbook = objExcelWorkBooks.Open(strFileName, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing,

                    Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                objExcelWorkSheet = (Worksheet)objExcelWorkbook.Worksheets.get_Item(1);  //获取sheet1工作薄



                int rowTotal = objExcelWorkSheet.UsedRange.Cells.Rows.Count;  //取得行数

                int columnTotal = objExcelWorkSheet.UsedRange.Cells.Columns.Count; //得到列数



                textBox1.Text = "共计" + rowTotal.ToString() + "数据";



                for (int i = 1; i < rowTotal + 1; i++)     //从第二行开始

                {

                    string meterNum = "";

                    string tempNum = "";

                    meterNum = ((Microsoft.Office.Interop.Excel.Range)objExcelWorkSheet.Cells[i, 1]).Text.ToString();   //赋值表号

                    for (int j = i + 1; j < rowTotal+1; j++)

                    { 

                     tempNum = ((Microsoft.Office.Interop.Excel.Range)objExcelWorkSheet.Cells[j, 1]).Text.ToString();

                     if (tempNum == meterNum)                                                                                  //表号比较

                     {

                         range = (Microsoft.Office.Interop.Excel.Range)objExcelWorkSheet.Rows[j, missing];

                         range.Delete(Microsoft.Office.Interop.Excel.XlDeleteShiftDirection.xlShiftUp);     //一样就删除，下面的行上移

                         rowTotal = objExcelWorkSheet.UsedRange.Cells.Rows.Count;                           //获取新的有效行数

                     }

                     

                    }

                    textBox2.Text = "处理第" + i.ToString();

                }

                string fileName = System.Windows.Forms.Application.StartupPath + "处理后.xlsx";

                objExcelWorkbook.SaveAs(fileName, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing,

                XlSaveAsAccessMode.xlNoChange, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                //Creat_ConfigExl((exlFileName + "配置表.xlsx"), meterNo, rowTotal);    //add 2017-7-13



                objExcelApp.Quit();       //要退出EXCEL操作，否则进程不会被结束，占用资源

                //Write_ToExl(meterNo,meterColumn);              

            }