Petrol Station
Contens:
Flame Arresters for Petrol Station
E 85 and HBEF (High Blend Ethanol Fuels)
Diesel ethanol blends (E-Diesel, Diesohol, Oxy-diesel, Etamax D)
Pressure release valve
Orifice plate versus pressure vacuum valve
Flame Arresters for Petrol Station
Storage systems for inflamable liquids (e.g. petrol) have to be equipped with flame arresters at all openings.
A flame arrester is a device to stop a flame entering a pipe in case of ignition and is designed to protect the safety of workers, the public, property and the environment.
The type of flame arrester installed at the end of a vent pipe is called an “end of line flame arrester”.
A flame arrester installed in a pipe (both side connected) is called “in line flame arrester”.
Bulletin APEA 2009 The Flame Arrester
E 85 and HBEF (High Blend Ethanol Fuels)
Safety characteristics of ethanol (bio alcohol) and petrol are significantly different.
As soon as ethanol is added to petrol (E5,E10...E85) the upper explosions point (UEP) will change.
This means that an explosive gas atmosphere in an storage tank with more than 60% ethanol will exist across a wider temperature range than in a pure petrol storage tank.
As there is likelihood that a flammable atmosphere will be present in an HBEF storage tank, flame arresters are required in most countries to prevent a flame travelling through pipework into the tank.
Therefore flame arresters are required at all open entries to the tank vapour space including the following positions:
- Liquid delivery line
- The stage 1b vapour recovery connection
- The stage 2 vapour recovery connection between the dispenser and the vapour return line
- At the end of or in the vent pipe
For storage of petrol and ethanol petrol blends we are offering a wide range of different flame arresters approved in accordance with EN 12874 and ISO 16852:
End of line deflagration flame arresters:
Inline deflagration flame arresters:
Inline detonation flame arresters:
End of line deflagration flame arrester approved for endurance burning of hydrocarbons
and E85 (E90) (ethanol /gasoline mixtures containing maximum 90Vol% ethanol):
Liquid product end of line detonation flame arrester:
Diesel ethanol blends (E-Diesel, Diesohol, Oxy-diesel, Etamax D)
Ethanol/ diesel blends are in test around the globe.
For storage and handling of ethanol diesel blends the following has to be considered.
The flash point of diesel is >55°C . The flash point of ethanol is at 12°C.
As the flash point of pure diesel is high it makes its ignition risks small compared to petrol.
But things change extremely if diesel contains small amount of alcohol.
Alcohol lowers the flash point of the blend sharply and makes it highly flammable under normal conditions.
Under this circumstance storage systems of diesel even with small amount of ethanol have to be equipped with flame arresters approved for ethanol.
In most countries pressure vacuum valve (p/v valve) at the top of vents is required.
Such p/v valve avoids displacement of (VOC) vapours in to atmosphere and reduces contamination of ethanol petrol blends (E5, E10 ... E85) with air humidity.
To open a p/v valve pressure has to be created up to e.g. 30mbar. This 30 mbar pressure doesn’t sound like much, but in nearly empty 10.000 litre storage tank this pressure can create up to 300 litre benzene contained vapours.
Tanker driver, service engineer and forecourt employee are exposed to these vapours several times every day over years. This cannot be a healthy working environment.
For health and safety of workers at petrol station a pressure release valve is available.
Before opening the storage tank, the tanker driver or station manager can release the tank pressure manually through the bypass valve. After realising the pressure the valve is closing automatically and the pressure/ vacuum valve is in charge again.
Data Sheet Pressure release valve