Print this pageEquipment Damage
Surge pressures commonly cause the highest and lowest pressures that will ever occur in a system and hence cause the most damaging forces.
This can cause equipment failure when the pressures or forces reach excessive levels. We have seen damaged air valves, NRVs, control valves, vessels and exchangers and can directly relate this damage to surge. Some major companies believe that the majority of damage in process plants can be related to transients and surge.
But in some cases, the peak pressures and forces do not cause outright failure, but significantly reduce the life-span of equipment (and some pipes). Frequent surge pressures cause forces that move the station pipework and this can lead to fatigue, leaking flanges and eventually spills. Constant NRV slam significantly reduces the life expectancy of even the best NRVs and this can cause damage, higher repair and maintenance costs and the risk of reduced flow capacity and hence spills.
We use surge analysis to ensure that all of the components in a system work together and we can prepare operating procedures, and select equipment to ensure that damage and shortened life-spans do not occur.
This may as simple as changing the start-up procedures, or using soft stop mechanism to reduce fatigue. Air valve locations and types can be specified to reduce the overall surge pressure magnitude and frequency. Overall these remedial changes prevent failures and also reduce the maintenance needs.
