Silica gel desiccant reactivation is a common operating procedure regularly used and performed to remove moisture from saturated material.
Silica gel is used throughout industry to adsorb moisture and maintain low relative humidity thereby preventing product contamination and degradation. Silica gel is capable of adsorbing up to thirty percent of its own weight of water vapour.
The majority of Transformer Breathers used by the power generation industry contain indicating silica gel.
Silica gel is available in two primary types indicating and non-indicating. The indicating property is achieved by impregnation with cobalt chloride salt which is sensitive to water vapour.
Ineffective reactivation control can result in Transformer Breathers being maintained by up to three times more than is necessary.
Shorter maintenance periods have an impact on both time and cost.
The use of valved Transformer Breathers has eliminated the need to maintain the oil seal fluid level and combining this with improved reactivation contributes to further savings by extending the average maintenance period.
This article suggests a number of simple improvements to improve the practice and procedures for reactivation of silica gel.