DTE GAS COMPANY

Incident Narrative

ON DECEMBER 20, 2019 AT 05:30, THE LOCAL ONSITE PERSONNEL IDENTIFIED A FIRE IN THE REBOILER UNIT OF THE DEHY AND SHORTLY AFTER IT WAS CONFIRMED BY GAS CONTROL. GAS CONTROL MADE THE APPROPRIATE NOTIFICATIONS. THE NATIONAL RESPONSE CENTER AND THE MICHIGAN PUBLIC SERVICE COMMISSION WERE NOTIFIED. THE UNIT WAS SHUT DOWN AND FIRE WAS EXTINGUISHED. THERE WAS NO IMPACT TO GAS SUPPLY TO CUSTOMERS. THE EXTENT OF THE DAMAGE WAS ASSESSED. THE DEHY ALARM HISTORY AND OPERATIONAL DATA WAS EVALUATED FOR THE INITIAL ROOT CAUSE ANALYSIS. ON DECEMBER 21, 2019, THE TUBE BUNDLE WAS REMOVED, AND AN INSPECTION WAS COMPLETED. IT WAS DETERMINED THAT THE REBOILER BURNER TUBE HAD A WELD DEFECT. THE REBOILER BURNER TUBE ALLOWS THE GLYCOL TO BE HEATED FOR DEHYDRATION. WHEN THE REBOILER TUBE FAILED IT RELEASED GLYCOL AND THE GLYCOL CAUGHT FIRE. IT WAS DETERMINED THAT THE BUNDLE NEEDED TO BE REPLACED. ON DECEMBER 26, 2019, THE BURNER ASSEMBLY WAS INSTALLED AND ALIGNED INSIDE OF FIRE TUBES. THE FIRE TUBES WERE LEAK CHECKED OVERNIGHT. ON DECEMBER 26, 2019, THE VESSEL HEAD WAS INSTALLED AND LEAK CHECKED. ADDITIONALLY, THE BURNER ASSEMBLY, EXHAUST STACK, BURNER BOX, FUEL LINE AND TEG WERE INSTALLED AND REFILLED. ON DECEMBER 27, 2019, THE REBOILER WAS REFILLED WITH GLYCOL. ON DECEMBER 28, 2019, ALL REPAIR WORK WAS COMPLETED ON THE BELLE RIVER DEHY. THE UNIT WAS BROUGHT ONLINE AT 16:30 AND WAS RUNNING CONTINUOUSLY. THE REBOILER TEMPERATURE WAS INITIAL HELD AT 300 DEGREES F AND BEING RAISED BY 25 DEGREES PER 1/2 HOUR. WE WERE FLOWING 3 MMCF/HR OF GAS THROUGH IT. ONCE IT REACHED FULL OPERATING TEMPERATURE OF 360 DEGREES F (AT APPROXIMATELY 20:00), IT RAN FOR A 24-HOUR TEST PERIOD. TEST PERIOD OF 24-HOURS WAS SUCCESSFULLY AND WAS AVAILABLE FOR GAS CONTROL FOR FULL USE.