Innovative Approach to Leak Detection Solves Several Problems for Plant Operators

Power plants operating hydrogen cooled generators face a few challenges regarding the safe and reliable supply of hydrogen to their electric power generators. The mode of hydrogen supply differs from plant to plant depending on such things as distance from the central hydrogen supply or permit restrictions on the amount of stored hydrogen. There are number of plants that utilize single cylinders or transportable cradles of six, twelve, or eighteen cylinders. Others utilize large bulk systems that are either stationary high or low pressure tanks or transportable high pressure tube trailers. Subsequently the volume of hydrogen on a particular power plant site can vary from a couple hundred cubic feet to over a hundred thousand cubic feet. One of the chief safety concerns that many plant operators are faced with is the possibility that a major generator casing leak or facility piping leak occurs while a large volume of hydrogen is “lined up” to continuously feed hydrogen to the generator. The operator is faced with few options to mitigate this safety risk. One method used to mitigate this risk is to isolate the hydrogen supply and manually feed hydrogen into the generator when monitored closely by plant personnel. Other approaches include the implementation of mass flow meters to monitor the flow of hydrogen and alarm if a prescribed limit is exceeded and excess flow valves that are designed to limit the amount of hydrogen flow going through them. An alternate and innovative approach has been implemented at a handful of power plants recently utilizing a Proton Exchange Membrane (PEM) hydrogen generator. The generator not only makes the hydrogen needed to maintain pressure and purity within the generator casing, but also has the inherent ability to monitor demand and alert plant operators if a hydrogen leak occurs.