An emergency shutdown system (ESD) is a system that is used in hazardous areas to prevent situations that could have devastating effects economically, environmentally, or operationally. Designed to minimize the consequences of emergency situations, they are a fundamental for any industrial structure to have.  Any injury to personnel or damage to equipment can be a tragedy for any engineering project whether it’s operational or not. By protecting against things like leaks, escape of hydrocarbons, fire outbreaks, and explosions an Emergency Shutdown System is without question, life-saving. It can be found on tankers, oilfields (oil well heads), oil and gas processing plants, gas and steam turbine power plants, and other industrial structures. 

Discover more about how emergency shutdown systems work in different applications and how temperature and pressure switches are used within them as below.

How do emergency shutdown systems work?

An ESD’s primary function is to determine when there is a critical condition within a system, and if there is, activating to quell possible leaks, explosions, or other types of major malfunctions is the crucial step. The activation of an ESD may include:
•    Shut down of part systems and equipment
•    Isolation of hydrocarbon inventories
•    Isolation of electrical equipment
•    Depressurization or blowdown
•    Emergency ventilation control
•    Closure of watertight doors and fire doors

For example, when used in a ship, the emergency shutdown system is in place to stop cargo liquid and vapour flow in the event of an emergency and to bring the cargo handling system to a safe, static condition. It is fitted to protect both the ship and terminal in the event of power loss, cryogenic or fire risks, on either the ship or in the terminal.

On carriers, their derivatives take a vital role for the safety of the ships from fire, containment protection, and gas handling system protection. ESD system communicates with its counterpart onshore with several communication links to share information about ESD cases.

When used in power plants, emergency shutdown systems are triggered by a few different things. In one application, once the temperature of gas exhaust reaches an unsafe level, an ESD will shut down the turbine producing the exhaust to lower the overall temperature of the system.

How are sensors or switches used within emergency shutdown systems?

Temperature and pressure switches are used in emergency shutdown systems to track the pressure and temperature setpoints. When the point which has been set is reached switches “snap” open or closed to activate the ESD using disc springs which are manufactured to ensure an accurate and immediate action is taken every time. 

These switches are installed within the emergency shutdown systems for components like compressors, pumps, turbines, or computer control systems that send a signal to trigger a shutdown. Pressure and temperature switches used in emergency shutdown systems need to be extremely reliable and durable to ensure the system activates when needed. 

To learn more about Van der Leun China’s switches and sensors designed for emergency shutdown systems, take a look at this page or contact us directly.