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Koch Expander Gas Heater

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Koch notified ParFab in Early April about their Expander Heater that had tube leaks and was not operating as required.

Let's dive into the details of this project and learn how ParFab was able to assist Koch with their Expander Heater.

Project Details

  • ParFab Industries Job 4522 Koch Expander Gas Heater
  • Project start date June 18, 2022
  • Project completion date August 19, 2022


After several attempts to plug tubes in the field, it was decided by Koch that the Expander Gas Heater needed to be pulled out of service so that a more thorough inspection and testing could be performed to isolate the exact issues causing the failure. Currently replacing the entire Heater was impossible due to limited materials and fabrication schedules.

After the ParFab team reviewed the project, the team decided that this repair could be successfully completed within a quick turnaround schedule.

Note: Due to the complexity and the condition of the heater, no other company would agree to dismantle it, replace, or modify the parts required to make it operational again.

ParFab was told that the design for the Expander Heater was unique and rare as there are only 3 units exactly like it in existence. After consulting with the original manufacture, ParFab Team accepted the challenge to fabricate the project quickly, confident that our team had both experienced and qualified personnel who could complete the task on time.

The plan was to remove the heater and ship to ParFabs facility in July on a scheduled turnaround.  As we in this industry know things happen and changes are made. Ahead of the scheduled shutdown date, the unit failed to produce as required due to new leaks. The customer contacted our team immediately, and we committed to do whatever was necessary to take care of them and get it back in service.


The unit was removed at the site and loaded on a truck for transportation to ParFabs facility located in Inola, OK. 

To make matters worse, as the truck was headed to Inola with the unit, the truck had an accident and turned over which in turn caused more damage to the heater. When we received the heater, ParFab and Koch personnel assessed the new damage in addition to what needed to be repaired and developed a plan.

We worked with a mineral recovery team and took the following steps to test for leaks, remove the bundle for repair, and make modifications.

  • Expander gas heater arrived at ParFab on June 18, 2022, and an initial smoke leak test was performed. The smoke test revealed that the top expansion joint was leaking, therefore more testing would be required.
  • The gas heater was stood in the vertical and secured to ParFab’s refractory casting tower.  The bundle was removed from the pressure shell and both the shell and bundle were transported to the testing facility.  Tubes were checked for leaks and after identifying the leaking tubes they were plugged.
  • During the initial receipt inspection of the shell, it was decided by all parties the top mating flange would be removed and replaced, along with some internal parts.  After the new parts were welded on the unit, the repaired bundle was reinstalled in the shell along with a new expansion joint.  After the bundle install was complete, the heat shield and other internal parts were repaired or replaced, and final pressure testing performed with acceptable results.
  • The Expander Gas Heater was then loaded for transport and was sent back to the job site.

The customer later reported that the repair and all modifications were successful as the unit is in service and performing to an acceptable limit.  A new unit can now be fabricated for a later replacement.

Client Background:


Koch Heat Transfer company is part of Koch Engineered Solutions – a global true one-source provider of products, technologies, services and expertise for multiple industries such as refining, chemicals, gas processing, petrochemicals, offshore oil and gas production, tertiary oil recovery, food processing  and municipalities.

Koch Expander Gas Heater

Koch notified ParFab in Early April about their Expander Heater that had tube leaks and was not operating as required.