Presumed to be chimneys, those are Flare Stacks, which are there at the oil refineries. It is used for burning the extra natural gases using chemical processes, from the pressure relieved valves for protecting refinery equipment as with the system’s normal pressure, it won’t burn and can cause an explosion. These Flare Stacks resemble a kitchen chimney but the working and features of both are very different.
The waste gas is also burnt using it; however, it has been limited since the last few decades, because of the increasing pollution. Today the waste gas is generally stored and further sold by proper high dilution in the natural existing gas supply.
The oil refineries and the chemical plants, both have the flare stacks for controlling the environmental impact that can be caused by the hydrocarbons release. Though there are also certain safety impacts as one wouldn’t want the large quantities of the flammable vapors getting built up in an area.
The safety valves have a connection with the Flare, where some of the gases, which are separated from the oil, get flared off, and the rest is further transported for processing to the other refinery.
These glasses are burnt while the refining process takes place for making petrol, diesel & alike. It decreases the amount of pollutants. In the oil refineries, different hydrocarbons are separated from the crude oil, and only a small amount of such (methane) is released in the air. It is a type of pollutant and, therefore, required to be burnt instead of allowing it to affect the environment.
These Flares Stacks are also seen on the oil rigs as it is useful for reducing the harm which can be caused to the environment by the gases and helps reduce the chance of explosion. Either way, the excessive or dangerous gases get burnt off. It also helps to indicate the amount of oil pressure that is coming up from below the ground.
Moving ahead to the Flare Stacks structure, the top part all the opening has the presence of a constant flame, which helps in igniting the flammable gases discharged. If there is an issue with the process that can result in over-pressurization of the production equipment, the pressure gets vented to the vessel system and the pipes, leading to the Stack. It doesn’t just allow the gases to vent out but burns them off. The natural gas also includes some contaminants like the hydrogen sulfide or hydrogen, which can neither be collected nor purified and are therefore required to be burnt off.
The Flare Stacks it acts as a safety device. Any screw up due to the human error or any kind of mechanical difficulties or control failure can cause a build-up of dangerous pressure, which needs to be relieved to avoid the explosion. The Flare also serves as an emergency pressure relief system or the last resort. With the flame getting smaller, remember, the gases are being burnt. However, if the flame gets large suddenly, there is an occurrence of overpressure event and Flare Stack is trying to relive the pressure to protect the refinery from a catastrophic event.
So remember, what you see is not a chimney at the oil refineries. Those are Flare Stacks, which helps protect the atmosphere and to relieve the pressure.