subject: Points To Consider Before You Repair Or Replace Your Heat Exchanger [print this page] Any failure in heat exchangers can lead to various problems. All the unsuccessful attempts to operate it indicate various problems arising from chemical reactions to faulty mechanical designs.
As a plant manager, there are several considerations to make before making a decision on whether to repair or replace your heat exchanger-
1.Analyse Performance: If the heat exchanger which is giving you a problem is less than 30 years old then the issues arising out of it could be related to cycling, water chemistry, operating failures and few more variety which would lead to dynamics of vibration and velocity. All these factors can be easily diagnosed. In case of any tube failure, performance analysis can guide the verification of flow through heat exchangers and the temperature passing through and from the system along with the intensity of the pressure across the tubes.
2.Assisting Troubleshooting: Users should be able to solve a problem if its evident. One solution could be calling a professional, describing the situation and solving it. The service provider should be have the required knowledge to troubleshoot the problem, suggest the diagnosis, and suggest the simplest and easiest way to resolve and repair the problem.
3.Testing Methods Professionally: In case of difficulty in diagnosing the problem, or when a comprehensive analysis is needed, user generally would intimate a professional who would conduct enhanced survey and sophisticated testing to provide correct recommendations for the damage. Several types of testing and repair methods are available like magnetic particle testing, hydrostatic, ultrasonic, eddy current, depending on the need of an hour.
4.Pulling a Sample of the Tube: In many instances its imperative to cut and remove a tube sample for failure diagnosis. This helps in examining the exact location and cause of a failure. It helps in determining the reason like stress cracking of tubes, chemistry, pitting, a failed weld or a percentage of tube wall loss. Continuous analysis will help in indicating possibilities of tube failures which could be imminent or could be problematic for a long period.
Removing a tube sample can be of crucial help in determining whether a heat exchanger repair services are required or it needs to be replaced. If repair is required, then the procedures as well as the stipulated time involved.
5.Testing and Repair should be done Simultaneously: The criteria for selection between repair and replacement of heat exchanger vary from system to system on various considerations. Downtime is certainly one of the most crucial factors. However it can also be eliminated if the service provider has the ability to provide both the services simultaneously.
6.Replace vs. Rebuild: if there is an extensive damage to heat exchangers or other heat transfer equipments, service provider might recommend replacing or rebuilding the unit depending on their inclination of selling a new product. Either of the choices can have a huge impact on downtime cost. In few cases replacement cannot be avoided. Keeping them would lead to increase in production cost and operational loss.
The best solution is to keep an open mind about the alternative of replacing or rebuilding the equipment considering two factors. Restoring the efficiency of heat transfer and hence extend its life or spend on a new equipment altogether by spending additional capital.
