Heat Trace Inside Coal-Fired Power Plants

Submitted by Nathan Ehresman || Valin Corporation
on Fri, 06/30/2017
There are many components and different varieties of instrumentation within today’s coal-fired power generation plants. In order for these components to continue to operate with maximum efficiency, one must do everything possible to minimize the risk of failure. One element of critical preventative maintenance is keeping everything at a temperature that will not cause instrumentation to freeze. If an operator’s instrumentation fails, the consequences can be disastrous. Without certain instrumentation fully functioning, the operator loses his or her “eyes and ears” of the plant. There is certain equipment that is absolutely critical to a power generating plant performing at an optimal level. This heating requirement can be a tricky practice, however, as heating systems need to be designed in such a way that they provide the necessary heat while taking into account any possible safety hazards. Generally, a plant has an ample amount of combustible materials present. If heating is not done in a responsible, monitored manner, there is a possibility of causing costly fires or in some extreme cases, explosions. Most power generating plants’ top priority is always going to be its workers’ safety.

When installing a heat trace system to a plant’s instrumentation, it does have to be sized appropriately, with a good amount of thought guiding where its power point is located. When a heat trace system is configured for a specific plant, there is going to be a home run or grid power connection point voltage drop somewhere. This location has to be well designed so that it is in a logical place. By paying close attention to this, engineers can be assured there are not more circuits present than necessary, reducing the amount of overall amp draw. A well-planned system will also reduce the amount of installation time required as well, ultimately saving on cost.

Proper Maintenance

Just as critical as proper installation and setup of a heat trace system inside of the power plant is the maintenance of it. Unfortunately, heat trace does, in fact, degrade over time. Generally, one will observe noticeable deterioration on the heat trace system between and five and ten years into its lifespan. These observations should not be taken lightly. Power plant personnel should make a coordinated effort to check the health of the heat trace system on a regular basis, especially when nearing this time frame. Allowing preventative maintenance experts to gauge the relative health of the heat trace system that is in place will provide the plant with an opportunity to perform upgrades and repairs during scheduled outages. By taking advantage of scheduled outages for required maintenance on the heat trace system, the plant will maximize its ability to avoid unplanned outages due to deterioration.

Applications

A growing trend in the industry is the use of wireless controls for their heat trace system. By utilizing wireless transmitters, operators are able to completely integrate their heat trace system into the vast amounts of data that is being monitored and analyzed. This benefit is left on the table far too often. This practice comes with special considerations that must be accounted for. For example, sometimes when these systems are set up, there is an output with the heat trace that is simply going nowhere. An operator must understand what kind of integration or communication is associated with their particular heat trace system. If the heat trace is not communicating properly, the operator will have no real idea of what is happening. Most heat trace systems have an alarm functionality built in to it. This allows a signal to be sent to the operator if a certain line is not functioning properly. There are many instances within power plants where an alarm is “sounding,” but that information is not going anywhere, there is no way for the operator to know about it and address the situation. If everything is working, an operator should not have to think about it, but if isn’t, he or she needs to know.

Another growing application of heat trace solutions inside of coal-fired power plants has to do with keeping the chute clean. Many power plants will spray down coal with a water-based chemical solution in order to cut down on dust. However, during colder winter months, this solution can often freeze in the chute. Power plant employees are then forced to dedicate valuable time to cleaning the chute, sometimes taking all day. This can be a costly, potentially dangerous job if not taken very seriously. As a solution to this common problem, a heat trace system can be carefully designed and installed to prevent the coal from freezing. This heat trace solution, if properly done, is a low maintenance solution to this issue as it only requires a cold-weather startup once a year before the temperature begins to drop. This startup can be incorporated into a plant’s regular maintenance, and if done properly, will ensure the heat trace system works correctly in future seasons.

Heat trace technology is continually growing and more applications are being discovered. Each application presents a unique set of challenges that must be overcome. However, the end result is a more efficient coal-fired power plant that communicates effectively with its operator.

Article featured in Energy-Tech Magazine.
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