Michell Instruments’ on-line and portable dew point hygrometers provide a complete solution to monitor moisture levels and reduce the risk of explosion in hydrogen-cooled electricity generators.
Using hydrogen as a coolant in the power generation industry is common practice: it has an extremely high heat transfer capacity and is more efficient than any other medium. However, this efficiency has its price, as hydrogen is also highly flammable. The higher the moisture level is, the higher the potential for corrosion of the generator internals. High moisture levels lower the thermal conductivity (and therefore efficiency) of the hydrogen. Also, condensed moisture within the system increases the risk of the hydrogen in the system simultaneously igniting – a phenomenon known as ‘flashover’. The risk of this is avoided by ensuring that the dew point of the moisture in the hydrogen is kept to a safe margin below the minimum temperature of the casing, typically around 0°C, to avoid condensation.
As it is not possible to hermetically seal the generator casings, there is potential for moisture to ingress from the surrounding air. The heat exchanger itself will also become more prone to leakage due to corrosion with age, allowing moisture to seep into the hydrogen, so constant measurement is vital to ensure that the dew point remains at a safe level below ambient temperature. There are two options: either continual monitoring or regular spot-checks of the system.
Continuous measurement ensures that the current dew point of the system is always available and alarms can be triggered if it rises above the ambient level. ATEX certified dew-point transmitters, such as Michell’s Easidew PRO I.S. and Easidew TX I.S. are well suited to this application as they can be used to measure the dew-point of flammable gases within the hazardous area. As hydrogen constitutes an explosion risk, a digital indicator, if required, should be installed in a safe location, remote from the generator set. Both transmitters provide a 4-20 mA output signal covering the range -100 to +20°C.
A portable dew-point hygrometer, such as Michell’s MDM300 I.S., may be used for making spot-checks of moisture in the system. This can either provide a fail-safe for the online moisture analyzers, or as the main method of measuring moisture. Portable instruments can be highly cost-effective as they can be used for spot checks in more than one location in a plant, eg also for transformer drying applications.
Contact AMS Instrumentation & Calibration Pty Ltd
Thank you for your enquiry! AMS Instrumentation &
Calibration Pty Ltd will be in touch as soon as possible.
Sorry, there seems to have been an error.
Please double check your details and try again.
- Transport Bulk Material with Curved Belt Conveying Systems
- Total Air Solutions for Pressure and Vacuum Pneumatic Conveying
- GreaseMax Continuous Lubrication Reduces Vibration-Caused Bearing Damage
- Total Air Solutions For the Powder Handling Industry
More Articles From AMS Instrumentation & Calibration Pty Ltd
- Mass Flow in Flare Gas Measurement
- Dual Function FS10i Flow Switch/Monitor Performs Double-Duty In Air Or Other Gases To Cut Plant Costs
- FCI Flow Switch Ensures Accurate Chemical Injection or Additive Monitoring for Process Control and Quality
- Next-Gen MT100 Air/Gas Flow Meters For Large Diameter Pipes, Stacks and Ducts