Purpose

In the past, plant engineers have resorted to cutting pipes and disassembling equipment to gain access to difficult to reach areas needed to evaluate the structural integrity and cleanliness of plant systems. This can be expensive, time consuming, and adversely impacts the plant’s ability to promptly return to normal operation. Non Destructive Evaluation (NDE) methods such as Visual Inspection and Foreign Object Search and Retrieval (FOSAR) can help reduce cost and downtime.

Challenge

There are approximately 600 coal-fired power plants in the United States, 18 are located in the state of New York. These plants undergo stringent EPA and regulatory oversight often requiring them to undergo routine maintenance on an annual basis. In one Western New York plant, engineers discovered that a stainless steel grating system, located upstream from a booster pump, had failed from violent back pressure build-up causing it to explode. The explosion sent metal fragments into the process piping system. Replacing the grating and locating the loose parts became the top priorities. The metal fragments from the explosion, if left in placed, could potentially migrate downstream and enter into the booster pump causing a catastrophic failure during startup.

Locating the loose parts was no simple task. The explosion scattered metal fragments along 7-90 degree elbows over a combined distance of 50 feet. Traditionally, engineers would resort to cutting each 90 degree section to gain access and remove the loose part. An alternative and less costly option would be to employ FOSAR tools and techniques to locate and retrieve the loose part. However, navigating multiple bends introduced a significant amount of friction restricting the effectiveness of standard FOSAR tools such as fiberglass push rods and pole cameras.

Solution

Jamko’s rapid response team was deployed and on site within 24 hours. A retrieval plan was created to locate and retrieve the foreign objects while adhering to the fundamental rule, “… identify and retrieve the foreign objects without introducing more foreign objects.”

To address the friction issues from the 90 degree elbows, our team utilized the INVU inspection scope. The INVU’s unique spring coil design provided enough flexibility to overcome the friction issues yet was rigid enough to be pushed along the length of the pipe. In addition, manually operated pneumatic grippers were used to securely grasp the large metal fragments in varying locations along the multiple bends during the retrieval process.

Over the course of 12 hours, our technicians were able to locate and safely retrieve every fragment. In addition, a post inspection was performed verifying the cleanliness of the process piping system. In contrast to more traditional destructive