In petrochemical facilities and refineries flares are important for safety. These burn the excess hydrocarbon gases in a safe manner as these can’t be recycled or recovered. These excess hydrocarbon gases are burnt in the flare systems in a manner that is environmentally-sound. This is an alternative to releasing this vapor directly into our atmosphere.
When flaring occurs this excess gas is combined with air and or steam and burnt off in the flare system which produces carbon dioxide and water vapor. This process is similar to the burning of LPG or liquefied petroleum gases. Some of us use these as fuel for home cooking.
Flair use is minimized as much as possible, but it can occur during a shut down or a start-up of any one of our facilities during the maintenance period or during unplanned operational interruptions such as a power outage.
Where does This Flaring take Place?
1) Solution Gas Flaring
When natural gas is contained in crude oil we call this solution gas. We use flaring to dispose of natural gas along with bitumen and crude oil. The gas is then recovered and piped to a processing facility. When you have oil underground the reservoir pressure holds the gas in the oil. When the oil comes to the surface, the pressure is reduced at facilities called batteries where this occurs. This is where production from one or more wells is stored and produced.
2) Gas Plant Flaring
At Gas Processing plants water, CO2, H2S, and natural gas liquids from raw natural gas are made into natural gas that is ready for the market. The flares are used to dispose of the gas that is unmarketable. All plants use flares to burn off gas during upset conditions or emergencies that impact the normal day-to-day operations of the plant. Many small plants are licensed to flare H2S rich gas once it has been removed.
3) Well Test Flaring
During the testing of all oil and gas wells, we use well test flaring. To determine the types of fluids the well can produce, this is a standard practice. The flow rates of fluids, the pressure and the other characteristics of the underground reservoir must also be looked at. If pipelines are nearby, operators may be able to direct the test gas processing plant in a process called in-line testing. For some exploratory wells this process is not practical or feasible as there may be no processing plants or pipelines nearby.
The composition, flow, and the pressure of the gas has to be determined by the processing plant or the pipelines before it can be handled safely. The information gathered determines the economic value of the well and the type of production facilities need to be installed. During under balanced drilling, additional flaring occurs which disposes of the gas which rises to the surface. This reduces the damage to producing formations by the drilling fluids as well as speeds the drilling. After certain well servicing operations, test flaring may be necessary. On average, the flaring duration is 2.5 days
4) Natural Gas Battery and Pipeline Flaring
At field facilities like dehydrators, wells, gathering pipelines, compressors, this type of flaring can occur. The flares burn off gas during maintenance shutdowns, emergencies, equipment failures, and other conditions.
Why do Natural Gas Facilities have Flare Stacks?
To prevent the accumulation of gases that might be a hazard, flare stacks are used as a safety measure. At sour gas facilities were H2S is flammable slightly heavier than air, and toxic this is very important. H2S is converted into Sulphur dioxide through combustion and can be toxic, but during flaring it is lifted by the plume of gases and it’s dispersed into the atmosphere. SO2 gases released into the atmosphere is regulated by air quality guidelines provided by the government.