Table of Content
- LPG Usage Areas and Features
- LPG Storage Tanks And Tank Accessories
- Typical Spherical LPG Tank Operations
- Over Pressure Protection İn LPG Tanks
- Firefighting Tactics and Leak Prevent
- January 4, 1966, Feyzin Refinery Bleve
LPG Usage Areas and Features
Developing technology and rising living standards have made energy one of our most important needs. In this context, Liquid Petroleum Gas (LPG), one of the important energy sources, has been among our most basic needs in today's conditions. LPG, which in all areas of our lives, consumes both cylinder gas and autogas.
LPG consists of a mixture of butane and propane gases. LPG is produced by processing petroleum in refineries or from natural gas deposits. LPG in the gas phase under normal conditions. But it is stored under pressure and in the form of liquid.
LPG, which is liquefied for transportation and storage, is consumed in the gas phase. It has flammable and combustible properties. It is very slightly soluble in water. It is colorless and odorless. For this reason, it is odorization with mercaptans or sulfur compounds so that it can be detected in case of gas leakage. The presence of 2% to 9% in the air is a sufficient mixing ratio for the risk of explosion. For this reason, both storage and transfer should with strict safety codes and rules.
LPG Storage Tanks And Tank Accessories
In the filling facilities and terminals, LPG is stored in liquefied form under pressure in specially designed cylindrical and spherical tanks. LPG is stored in tanks in three ways propane, butane, or mix. Propane has the highest vapor pressure and propane storage tanks are designed to resistant higher pressures.
Read More, Storage and Handling Safety in LPG Plants
Typical Spherical LPG Tank Operations
A typical Spherical LPG tank can be built from 1000 m3 to 5000 m3 volume and has multiple nozzles and connection points. Of these, the most valve open-close operations are in the liquid, gas phase inlets and drain lines. For this reason, these areas critical zones for operational safety. Past disasters have shown us how important these areas and even drainage operations.
Over Pressure Protection İn LPG Tanks
Safety valves are used to protect the tank from explosion when the LPG tank's vapor pressure increases above the design pressure for any reason. The selection of safety valves should be made according to engineering calculations and API standards and should be tested by expert inspectors at least once every five years.
Safety valves are the silent guards of the tanks and are the most important safety equipment on the tank.
Firefighting Tactics and Leak Prevent
Leakage prevent system
There should be zero tolerance for leakage in LPG storage tanks. In this context, all inlet and outlet nozzles of the tanks should be equipped with remotely operable emergency shut-off valves in case of leaks. LPG leaks or other emergencies may happen in tanks or pipelines. Thanks to this emergency shut-off system, control of LPG spread out of the tank is prevented in case of emergency. It is recommended to test this emergency shut-off system with regular periods.
In addition, attention should be attention to zones where LPG can be collected in case of leakage, such as storm drains and sewers around LPG tanks.
Fire fighting Systems in LPG tanks
The most important active fire protection system in LPG tanks is the sprinkler system on the spherical LPG tank. All important details are written at NFPA 58 and API 2510&API2510A, For example, How many liters of water should be applied per square meter of the tank shells per minute, how much water reserve you should have for fire fighting, fire pump flow rates, etc. Firefighting systems should be designed in accordance with this standard, otherwise, you can not win this dangerous war.
Emergency action plan in LPG Tank fires; The first action to take in LPG tank fire time is to stop the source of the burning LPG, otherwise, it is not possible to extinguish LPG fires. In this type of fire, emergency shut-off valves play a most important role. If the source of the LPG leak in the fire is stopped and the LPG in the pipeline runs out, the fire will continue for some time but the fire will stop when the LPG runs out. In the meantime, if the fire zone is wetted with the water, unwanted scenarios may not occur. Because fire intensity will decrease as LPG and oxygen in the amount of air will decrease due to the evaporation of water. LPG fires can occur as jet fire, UVCE, and BLEVE. Of course, the worst of these three fires can be BLEVE. Terminals and facilities should plan the largest portion of the fire fighting plan with barriers that can prevent BLEVE.