Drone Inspection of an Air-Cooled Condenser at Pellet-Fed Biomass Facility

DJM Aerial deployed the Elios 3 to inspect air-cooled condenser ducts 40 meters above the world’s largest pellet-fed biomass facility.   

Benefits In A Nutshell

Air-cooled condenser (ACC) systems are hard to miss and critical to the operations of biomass and similar power generation sites. ACCs use a series of ducts and fans to cool and condense exhaust turbine steam.

Inspecting ACC systems is incredibly challenging. Due to the intricate structure typically being elevated and made up of a series of fan draft systems, pipework, and fins, an inspection of the ACC requires complex and prolonged work at height.

An ACC inspection searches for corrosion and coating degradation, in addition to mechanical distortion, joint movement, bellow deterioration, fatigue around seams and interfaces, and general checks for wear and tear. These routine inspections are critical to preventive maintenance strategies; however, due to traditionally being disruptive, hazardous, and slow, they are a challenge to schedule and perform. Drones are changing that.

Drone Inspection of an Air-Cooled Condenser System at World's Largest Pellet-Fed Biomass Facility

DJM Aerial Solutions, an advanced drone inspection and surveying company, leverages drone technology to deliver tailored, high-precision remote inspections. They were asked by the facility to inspect the ACC air supply, with their expertise in heavy industry and mechanical engineering expected to assist their efforts to conduct a quick, efficient inspection.

The power generation site being surveyed is a leading pellet-fed biomass facility in Middlesbrough in the UK. The internal ACC air supply system needed to be inspected, but it is suspended 40 meters above the ground and completely inaccessible without using scaffolding, cherry lifts, and confined space entry to visually inspect the interiors of the ducts. It’s incredibly challenging to access, and the plant cannot afford prolonged downtime due to the high energy demand it serves.

The air-cooled condenser system hosts a series of ducts, pumps, and fans to condense steam, and inspecting it can be a long, tedious process

DJM Aerial Solutions visited the site and assessed the situation. Immediately, they knew that the best way to inspect this ACC system would be with the Elios 3 drone.

How Can You Use a Drone for Air-Cooled Condenser Inspections? 

A traditional duct system inspection would require scaffolding, involving hazards from work at height and inside the ducts, alongside freezing any work below the structure. Internal duct inspections are necessary, further complicating the task. This calls for prolonged safety checks, a stand-by rescue team, permit controls, and strict restrictions on the inspection operation.

The result? Higher costs, higher labor demands, and a great deal of logistical organization to complete a routine inspection.

DJM Aerial turned to the Elios 3 as they knew it would simplify the inspection operation. Not only would it eliminate the need for work at height or confined space entry, but its features would deliver the exact data needed to assess the system.

Feature Spotlight: 

• Lighting → The Elios 3 is equipped with a powerful lighting rig, illuminating a space with over 16,000 lumens. This gives clear visibility during the inspection to spot points of interest such as rust or similar defects.

• Visual Inspection → The 4K camera and thermal sensor on the Elios 3 show the pilot a clear picture of the area being inspected and allow them to identify hot/cool spots in areas with missing insulation.

• Ease of Flight → When flying between pipes, ducts, and vents, many drones would be taken out of the air. The Elios 3 is collision-tolerant and capable of maneuvering safely through these types of spaces without fear of impact causing it to crash.

• 3D Point Cloud → The Elios 3 captures LiDAR data using a SLAM algorithm, providing the pilot with situational awareness during the flight and delivering a 3D model at the end of the mission, acting as a digital twin of the system under inspection. All points of interest are localized within the 3D model, allowing maintenance teams to identify problem areas and strategize the most efficient methods to inspect the space.

Inspecting ACC Systems with the Elios 3

The DJM Aerial team deployed the Elios 3 drone for a visual inspection of the cooling system, focusing on identifying problems and flagging them for the site managers.

First, they visually assessed the circumferential and longitudinal seams of the ACC system, as well as checking the expansion bellows, internal structural interfaces, and assessing areas vulnerable to corrosion and coating degradation. The drone pilot kept an eye out for mechanical damage in addition to inspecting the duct wall conditions.

A pilot from the DJM Aerial Solutions team flies the Elios 3 inside a duct, using an access hatch to fly the drone 

Next, they flew the vertical ducts in the building to ensure they had complete coverage of the systems being inspected regardless of position.

Finally, thanks to the Elios 3’s stable flight style, they could then fly inside the ducts to assess the seams from the duct interiors, before moving on to check the bellows. Doing this with the Elios 3 completely eliminated the need for confined space entry, simplifying the entire inspection process and saving substantial labor and additional safety costs.

Impact of a Drone Condenser Inspection