by Atul Bansal, Chief Operating Officer, Technical Drying Services
Coating forms an integral part of various industrial processes in power plants and refineries. Considering that the facilities abode complex and critical operations, it necessitates checking coating failures to drive the efficiency of the other processes. Here, moisture emerges as the major threat compromising the efficacy of the coating process, thereby necessitating maintenance of ideal environmental conditions. Exercising proper control of humidity levels within facilities entailing tanks, columns, reactors, coke drums, vessels, pipelines, etc. helps in driving optimal results.
Coating forms a protective layer in the tanks, which in the presence of moisture can undergo deterioration and adversely affect the various processes at the same time. Therefore, in order to protect the tangibility of coating, humidity should be thoroughly eliminated from the facility. Even the slightest trace of humidity can cause inadequate surface preparation, culminating in blistering, cracking, peeling, and cratering on the surface. It can significantly shrink the life of the coating system and ultimately defy the proper adhesion between the substrate and the coating. Consequently, improper surface preparation can translate into approximately 95% premature coating failure.
Delving deeper into the repercussions, the factory setup contains tanks for housing chemicals such as petrochemicals, chemical gases, etc., which are highly sensitive and reactive in nature. The inadequate coating comes with the ability to wear off the surface, triggering the dilution and contamination of products stored within the space. The severity is further exacerbated during monsoon, where humidity can delay the operations in the powerplant and, if not checked in time, can even halt the smooth functioning of the processes. Similarly, during the night there is a spike in the tendency of cold weather, responsible for increasing the level of moisture in the air. Augmenting the chances of condensation on metal surface, it can lead to corrosion, referred to as rust bloom or flash rust. Therefore, all the factors together impede the productivity of the plants and prolong the completion of the project, but they can even account for the untimely downtime of the entire facility.
Therefore, as surface preparation defines the success of coating and other processes, it is essential to perform surface preparation in the absence of humidity. Employing desiccant dehumidification technology can be very helpful in mitigating the moisture throughout the processes, and come in handy for exercising optimal control over temperature, relative humidity (RH), and dew points. It creates clean and ideal environmental condition, which is a prerequisite for conducting industrial coating. In the process, it meets the technical specifications outlined by the industry and bodes well for supporting the coating and likewise, painting processes.
Leveraging the advanced dehumidification technology, the industry players can maintain a relative humidity of less than 55% within the tank. It also aids in regulating the temperature and limiting it in the range of 30° C to 35° C while performing the blasting, painting, and coating jobs. It goes a long way in monitoring the environmental conditions during the night as well. The dehumidifiers come with the proficiency to achieve a constant dew point differential of -5° C between the air and surface temperature of the sheet to be coated. At the same time, it maintains a dew point differential of -12° C between air inside the tank or silo and outside air.
Elaborating on the benefits of the dehumidification system, it offers an easy solution enabling proper surface preparation leading to effective coating application. Keeping humidity levels within a very narrow range, it drives the elimination of moisture from the entire coating system. In the process, dehumidifiers invariably contribute to resisting condensation and rust bloom at the time of performing blasting and painting operations. The systems also play a pivotal role in curbing blistering and curing failures, and aid in promoting anti-corrosive painting by facilitating strong intercoat adhesion, and improve coating life by 1.5 to 2 times.
In addition to supporting proper coating operation, the dehumidification technology provides cost-effective solutions at the same time. The benefits of advanced technology extending beyond coating to blasting and painting processes as well, saves 2-4% of total cost that would have otherwise gone into conducting corrosion preventive painting. Moreover, blasting, painting, and coating are not influenced by the outside weather conditions in the presence of dehumidifiers, fostering an ideal environment for conducting the processes all-round the year. As a result of this, the downtime of plants due to bad or unfavourable weather can be reduced significantly, which ultimately expedites the completion of the projects and translates to bringing down the cost by almost 35%.
Failing to install dehumidifiers can add to the complexity of the process, mandating blasting to be performed in a phased manner, followed by immediate painting to avoid any condensation in between the processes. The approach is not just impractical and hectic but is also a costly and time-consuming affair. Rather, making use of dehumidifiers can empower step-by-step blasting and painting in a single go, offering an economical solution for the powerplants.
The benefits of technology extend to the safety of occupants as well, considering that tanks are inherently confined spaces accompanied by dangerous settings. Moreover, at the time of blasting, hazardous fumes and inflammable vapours are released, which are responsible for surging the temperature within the enclosed space. All the factors together invariably increase the risk for those working inside the tanks, necessitating making arrangements for promoting the safety and productivity of the workers. Here, the dehumidifiers come to rescue, as they have ventilation systems as well, to facilitate temperature control of the space and foster a safe confined space, an important factor adding to the safety and productivity of the occupants.
Looking at the wide gamut of benefits dehumidification solution has to offer, it comes to light that application is not just limited to coating processes and empowers various operations at the same time. It can be considered a comprehensive solution for dealing with the humidity menace at different stages of operations in a powerplant.
