Excess gas burner (flare stack) in the Chemical Park Knapsack

What does the flame mean?

When the flare stack starts up in the polypropylene plant, it’s really rather spectacular. It can also, however, be unnerving, since the flame can reach a height of up to 30 meters sometimes producing soot and making a very loud noise. It can all be somewhat frightening – especially when it’s dark and the flame can be seen for miles.

There is certainly no need for alarm – except, of course, if you are worrying about the operational results of LyondellBasell’s plant in the Chemical Park Knapsack! There is, however, no safety risk involved – neither for the health of employees nor the neighboring community.

What’s actually happening when there is a flare off?

Similar to a gas lighter, the head of the flame is burning off propylene. Normally, polypropylene is produced from this gas. However, sometimes, due to particular circumstances, there is a disturbance in production. It is then, at times, necessary to shut down the plant, which normally runs around the clock, and to flame off the highly flammable propylene.

A safety system goes into effect: the gas flare off system starts and the propylene is burned off without danger to anyone or anything. Just like a gas lighter, the flame produces soot. If you hold a white plate over a gas lighter’s flame, you can quite easily see the soot produced. The flare off, of course, produces much more soot, but we know lots of other flames that burn pure carbon from our daily lives, such as candles, wood fires and gas stoves, which are unpleasant and dirty, but not poisonous. Soot occurs when the flame doesn’t get enough oxygen to burn off the propylene completely. When it is burned completely, only carbon dioxide and water is the result. In order to prevent any annoyance for the neighboring community, steam is added to the flare off process, whereby oxygen is transported to the middle of the flame. This however generates quite a lot of noise.

The flame off process is stopped either when the polypropylene plant resumes production or when all of the necessary gas has been burned off.

Apart from the fact that LyondellBasell doesn’t want to disturb anyone, the company itself is very interested in avoiding such an occurrence, since they are also losing a valuable raw material.