RISK: Vessels may burst due to material failure caused by very low temperature
Temperatures can drop to 100°C below freezing point during pressure relief. The steel in these containers must have enough strength even at these temperatures. Attaining this means that cryogenic steels are used – these types of steel cost considerably much more than “typical” ones. So how can such costs be avoided without making any comprise on safety?
To realize this, the following is necessary:
- The complex physical processes in a technical plant must be known precisely and
- Safety devices must be installed, they should work depending on…
… the operating and flow conditions as well as
… the gas type
This safety device should regulate emergency relief by ensuring that the conditions in the vessel do not get too cold on one hand and ensuring that permissible overpressure is not exceed on the other. In doing so, they should ensure that the recovering systems and flare systems installed downstream also work according to design.
This is exactly what a SmaLT – a SMArt Low Temperature protection device – does.
Pressure vessels, storage tanks, columns and pipelines in industries are protected against overpressure with safety devices – typically safety valves or bursting disk devices. These devices determine what overpressure and what temperature technical plant operates in. They are activated when the predefined and fixed opening pressure is reached. Typically the flow in the first stage of relief is too high for the flare to burn the content completely. In the later stages of relief, only a small amount of gas flow.
An intelligent safety device – Smart Low Temperature protection device – should regulate the flow during emergency relief such the permissible pressure and temperature in the vessel are not reached and at the same time limit the flow such that the recovering systems operate in the intended design conditions. Such controls are very hard to implement in technical plants considering the complexity of the physical processes – CSE intends to develop such SmaLTS.