Explosion Protection of Gas/Oil Fired Engines
Gas or oil powered engines are used in a wide variety of industries. They are often used as a flexible energy source or backup if there is a power outage or for systems that are rarely used. They also have some advantages: they are cleaner than diesel engines; They can be used much more quickly compared to “traditional” energy providers, which have a production time of only 6 months, and can run on a variety of fuels such as natural gas, LPG, methane, biogas and landfill gas, and sometimes waste oil. They have high efficiency, plus there can be heat recovery from hot exhaust to further increase efficiency.
Engines powered by gas or oil are designed to create “controlled” explosions to produce power. However, there is a risk of an uncontrolled explosion in the exhaust. Exhaust smoke is very hot, which heats metal surfaces and creates an ignition source. Friction between mechanical parts can also cause sparks. Therefore, if fuel gas reaches the exhaust, uncontrolled explosions may occur.
There are several reasons why unburned fuel reaches the exhaust. In a four-stroke engine, if the pistons are damaged or not synchronized, fuel can leak from the valves; If the engine is running cold or has low fuel concentration, it may not burn all the fuel, allowing all the exhaust to flow into it. The same applies if the engine is at high speed or at partial load; When the igniter fails, unburned mixture can be pushed through the exhaust.
Therefore, explosion protection is required to control any uncontrolled explosions in the exhaust. If the explosion moves in the opposite direction, the engine will be strong enough to withstand the explosion. However, the engine process may include silencers, catalytic convectors and heat exchangers that comply with environmental regulations. These parts are expensive with long lead times for replacement and they also need to be protected from explosions.
In this type of engines, explosion flaps are specially placed on the exhaust. If an explosion occurs, the pressure wave releases the explosion in a controlled manner, opening the vent without rupturing. If the system is indoors or near other equipment or personnel, it may be necessary to use a flameless explosion hood in which a fine mesh is placed under the vent.
The number and placement of blast flaps will depend on the length and geometry of the exhaust, so a proper analysis is vital to find the optimum solution. The most critical explosion hood location is the one closest to the engine exit.
By performing a detailed risk analysis, Elva ensures that safety comes first but does not waste resources by installing unnecessary explosion covers. The extremely robust design of the explosion flaps gives them a longer service life and minimizes maintenance times.
