Overspeed Protection Systems for Diesel Engines
How safe is your site?
Petroleum products play a vital role in our day to day lives, and confidence in the safety of the industry's operations is paramount. Diesel engine runaway is an unexpected danger for the operators of Oil & gas sites and has led to fatal accidents for companies involved in producing and storing gas, crude oil, petroleum, and reifined products.
What is diesel engine runaway?
'Runaway' is a dangerous phenomenon where the running diesel engine draws extra energy from low concentrations of any hydrocarbons in the surrounding air. This causes uncontrolled overspeed beyond the safe design limits and can lead to an explosion or ignition of the external air-fuel mixture.
'Airborne combustable hydrocarbons can blend with air causing an additional supply of energy"
Drawing in the surrounding mixture and using this energy as fuel is both unstable and uncontrollable. The engine's control system attempts to limit the diesel injection to keep the engine under control, but as more vapours are ingested, the speed will increase beyond the 'red line' and normal limits. This can cause internal valves to bounce exposing the combustion to the manifolds and the flames will pass out, meeting the flammable vapours being drawn in.
Diesel engines that are not properly controlled or protected present a dangerous source of ignition when used in areas where combustible vapors may exist. A resulting explosion often leads to signifigant consequences for people, refineries, and the environment.
Recent independant third-party tests performed by a leading engine OEM have shown that a diesel engine can start to runaway within 3 to 9 seconds of a gas being drawn in, at a concentration as low as 22% LEL. Once this begins, turning off the ignition key will not stop a diesel engine. Similarly, manual closure of the intake by a remote-control valve is unlikley to be fast enough to prevent serious consequences. There is very little margin for error if engine shutdown is dependant on human intervention!
Preventing diesel engine runaway.
The only proven, reliable method to stop the engine running away beyond a safe limit, is to install an automatic emergency shutoff valve in the engine's air intake system. Blocking the engine's air intake effectivley cuts off the external fuel source and air supply, so the engine quickly stops, and the ignition source is removed.
Few industries are more hazardous or more safety conscious than oil and gas. It takes a broad variety of diesel-powered equipment to successfully support site operations. Stationary diesel engines, mobile equipment, emergency response vehicles, and vehicle mounted engines should all be considered as a potential risk to operations.
For over 25 years, AMOT have been promoting safety by raising awareness of the explosive risks from runaway diesel engines and educating industry professionals of ways to better protect equipment and employees. We continue to invest in new products, technologies, and solutions to meet the evolving needs of modern engines with increasing perfrmance standards.
AMOT offers on-site training, consultations and public presentations to operators and managers and safety specialists to educate on international accident history, lessons learned, and best practices adopted within the global oil and gas industry.
Protect your workforce, plant, and equipment
Bayat Ahmed Al Owaidh
Phone: +966 50 417 4649