The Dutch contractor Wilton Heat Transfer Services was approached by a major gas production and distribution company regarding a problem with a heat exchanger in one of their process plants.
The gas formation from which they extract gas is nearing the end of its production life. As the production volume decreased, so did the flow rate and pressure of the feedstock to the processing plant. This decline disrupted the efficiency of the plant and caused the formation of gas hydrates in the tubes of the heat exchanger, which further reduced efficiency and led to more maintenance shutdowns—costs the end user could no longer tolerate. In close cooperation with the end user, Wilton Heat Transfer Services investigated a number of alternative solutions and ultimately chose a program involving tube plugging. This program would reduce the number of available tubes in the heat exchanger, thereby increasing the flow rate of the production gas through the tubes.
Addressing the problem
The flow conditions in the heat exchanger had changed and were no longer equal to the original design conditions. The heat exchanger was operating inefficiently, leading to more maintenance shutdowns, an inferior end product, safety issues, and higher costs.
Alternatives considered
Several alternatives were evaluated, including designing a new heat exchanger or tube bundle. Tube plugging initially seemed like a drastic option, until a pros and cons analysis was performed.
Ultimately, due to the speed with which it could be implemented and the overall operational flexibility it offered, tube plugging was chosen. Through a flow analysis, specific tubes were identified that needed to be plugged to eliminate hot/cold spots in the tube bundle. An analysis of tube plugging technologies was carried out, and a custom solution for tube plugging [Pop-A-Plug Tube Plugs from Curtiss-Wright EST Group] was selected and implemented.
Result
Wilton received and installed 1,200 plugs and completed the work within a week. Wilton Heat Transfer Services and the end user have included this solution in their options for future heat exchanger repairs.
Fritz Sutor – Curtiss-Wright - Vice President Business Development
