13 Scopes. 7 Days. One RNG Plant Shutdown.

How MIG completed plant-wide mechanical work during a fixed seven-day renewable natural gas facility outage. 

At a renewable natural gas facility, shutting down production starts a clock.

Landfill gas production continues, making outage windows short and highly coordinated. So when a major energy infrastructure company scheduled a full plant shutdown at one of its landfill-gas-to-RNG facilities in the Midwest, the outage window was fixed at just seven days.

Maddox Industrial Group (MIG) was responsible for 13 mechanical scopes across four work packages, covering new equipment installations, redundancy upgrades and maintenance and reliability repairs throughout the RNG facility.

The challenge was not simply completing the work.

It was completing all of it at the same time, safely, while roughly 70 contractor personnel from multiple companies shared the same site, access points and permitting process.

Managing 13 Mechanical Scopes During One RNG Plant Shutdown

The location of the horizontal exchanger created the defining challenge of the project.

MIG's scope included installation of a new CO2 blower, high-pressure pump and amine exchanger, along with replacement of an O2 knockout pot and O2 heat exchanger. Crews also installed a redundant diaphragm pump and a new pre-treat TOX manway.

Elsewhere in the facility, MIG installed bypass tie-ins and a flame arrestor, replaced eight orbit valves and actuators, added instrumentation taps and cleaned the inlet blower gas cooler.

Some of the work added new equipment. Some created redundancy so future maintenance could be performed without taking systems offline. Other scopes addressed existing equipment and reliability needs.

MIG self-performed the mechanical work with approximately 35 craft and supervision personnel at peak, allowing multiple crews to work simultaneously instead of completing one scope before moving to the next.

For the customer, that meant one mechanical contractor coordinating a significant portion of the outage under one management and safety structure.

Parallel Execution Kept the Seven-Day Plant Outage Moving

With no float built into the schedule, the work could not happen one project at a time.

Crews worked multiple fronts on 12-hour shifts, supported by project management, field supervision, safety oversight and quality control. Coordination with the owner and other contractors continued as equipment, permits, inspections and work areas became available.

That became especially important when field conditions did not perfectly match the issued drawings.

During heat exchanger work, MIG identified differences between the piping drawings and actual field conditions. Rather than allowing the discrepancy to stall the installation, the field team verified dimensions onsite, coordinated the adjustment with the owner's team and adapted the fabrication in the field.

The installation continued without giving back the outage schedule. Compressed outage schedules require field discrepancies to be identified, communicated and resolved quickly.

The work still has to move.

Maintaining Safety and Quality During a Compressed RNG Turnaround

Moving quickly did not change the requirements for the work.

MIG welds were subject to third-party nondestructive examination, including up to 100% coverage on lines that would not receive a pressure test. Butt welds were inspected using radiographic or phased-array ultrasonic testing, while socket and o-let welds received dye-penetrant testing. Flanged connections were assembled and torqued in accordance with ASME PCC-1.

Before opening any line, MIG foremen and the owner's operations team jointly walked down the system to verify lockout, tagout, isolation and purge conditions.

Across approximately 2,500 craft hours, multiple simultaneous work fronts and extensive hot work, the shutdown was completed with zero safety incidents.

Getting the RNG Facility Back Online in Seven Days

At the end of the outage, all 13 mechanical scopes were complete and the RNG facility returned to service on schedule.

The project also created another opportunity within TransTech Group. During the shutdown, the customer awarded MIG the removal and rebuild of a shell-and-tube heat exchanger, with the rebuild performed by sister company Metalforms in Beaumont, Texas.

For RNG plant owners planning maintenance and shutdown work, that is ultimately the value of consolidating mechanical scopes.

Instead of managing a patchwork of specialty contractors, one team can take responsibility for multiple work fronts, coordinate manpower and materials, operate under a common safety structure and adapt as field conditions change.

On this outage, that meant 13 scopes, four work packages and approximately 2,500 craft hours completed within one seven-day window.

The RNG facility went back online when it was supposed to.

See How MIG Executed the Full RNG Facility Shutdown

This project went far beyond what we can cover in one blog. Read the full case study for a closer look at the equipment installations, redundancy upgrades, maintenance work, field adjustments, safety requirements and coordination behind all 13 mechanical scopes.

Frequently Asked Questions About Heat Exchanger Replacement

What work can a mechanical contractor perform during an RNG plant shutdown?

Mechanical shutdown work can include new equipment installation, piping modifications, equipment replacement, redundancy upgrades and maintenance. On this project, MIG's scope included pumps, blowers, heat exchangers, vessels, valves, bypass piping, cooler cleaning and instrumentation connections.

How can multiple projects be completed during a short RNG plant outage?

This seven-day RNG shutdown relied on parallel execution. MIG deployed multiple crews across different work fronts simultaneously, supported by centralized project management, field supervision, safety oversight and quality control.

Does MIG provide maintenance and turnaround services for renewable natural gas facilities?

Yes. This project involved a landfill-gas-to-RNG facility and included mechanical work across several areas of the plant, including gas handling, amine equipment, pumps, heat exchangers, piping and reliability upgrades.

How does MIG handle unexpected field conditions during an RNG shutdown?

On this project, MIG verified actual field dimensions, coordinated changes directly with the owner's team and adapted fabrication onsite when conditions differed from the drawings. This allowed installation work to continue within the fixed outage window.

How does MIG maintain safety during a compressed plant shutdown?

For this outage, crews worked under daily safety meetings, job safety analyses, dedicated fire watches and required PPE. MIG and the owner's operations team also jointly verified lockout, tagout, isolation and purge conditions before lines were opened. The project was completed with zero safety incidents across approximately 2,500 craft hours.

Can MIG support RNG facility shutdowns across the United States?

MIG is licensed in 45 states and can deploy its crews, safety program and execution standards across a broad national footprint.