What is Gas Flaring? – Why is It Done & Viable Alternatives
September 24, 2019
Flare gas is a byproduct of numerous industrial processes including oil and gas recovery, petrochemical process, landfill gas production, and wastewater treatment. Although in large quantities it might be economically viable to employ the use of flare gas in heat and electricity production, in some cases flare gas may not be a cost-effective decision to attempt such energy recycling. A popular but controversial way of eliminating unwanted gas is by flaring.
Gas flaring is a major environmental concern facing the world today as it generates a significant amount of greenhouse gases which contribute to the overall burden of global warming. In this article, we will consider how gas flaring is done and alternatives like flare gas recovery systems which can be applied to minimize or eliminate this practice.
What is Gas Flaring?
Gas flaring refers to the combustion of associated gas generated during various processes including oil and gas recovery, CBM production, petrochemical process and landfill gas extraction.
The typical flare used in the oil and gas industry is composed of a boom or stack which collects the unwanted gases to be flared. At its tip is an air-assist mechanism which combines free air with the generated gases being burned to improve combustion efficiency. Some gases require oxidation due to low heating value and are combusted using a thermal oxidizer.
Some components of the flaring system include:
- Flashback seal drum
- Liquid knockout drum to remove water and oils from flare gas
- Flashback prevention unit which ensures combustion flame does not go beyond flare tip
Chemical Composition of Flare Gas
Flare gas mixtures differ depending on the generating source as chemical compositions vary across different industrial processes. For example, natural gas is composed mostly of methane, some ethane and variable quantities of other hydrocarbons and other gases.
The methane content of landfill gas is lower with comparably higher amounts of carbon dioxide. Overall, there is no standard composition as natural gas or landfill gas derives from two different operational sites will vary slightly.
Why Flare Gas?
Industries that utilize gas flaring cite various reasons for doing so. The most commonly stated reasons why natural gas is flared are:
- Pressure relief to prevent the risk of explosions from simply venting large amounts of reactive gases
- Waste product removal from chemical production processes
- Safe combustion of volatile organic compounds
How Is Gas Flaring Regulated?
The responsibility for establishing regulations on gas flaring is on the government of the region where the flaring is being done. In Texas, regulation is done through the Railroad Commission of Texas, with the Texas Commission on Environmental Quality (TCEQ) overseeing resultant air quality.
Although most oil-producing countries have established policies on gas flaring and emission regulation, implementation varies across regions. In some areas with lax monitoring and enforcement of regulations, adherence to flaring protocols is largely ignored by key oil and gas production players.
Flare Gas Power Generation & Other Alternatives
With the harmful effects of gas flaring on the environment, various economical alternatives have been introduced which involve using flare gas in other production processes. These gas flaring reduction methods are outlined below.
Flare Gas Power Generation Programs
Natural gas recovered from oil wells and landfill gases can be used to generate electricity. There are various ways of converting flare gas to electricity which include:
- Gas driven micro and large turbines
- Steam-driven turbines
- Reciprocating internal combustion engines
Flare gas can also be utilized in the cogeneration of heat and electricity.
Flare Gas Reinjection in Secondary Oil Recovery
Natural gas generated from oil and gas well can be injected into aged wells to restore dwindling natural formation pressure and maintain production outputs. This self-sustaining cycle is quite economical as waste generated is minimal and overall process efficiency is boosted.
Feedstock for Petrochemical Plants
Natural gas is the main raw material employed in petrochemical production processes. Rather than flaring associated gas from oil and gas wells, the flare gas can be channeled into the production of syngas, ammonia, hydrogen fuel for cars, or the manufacture of rubber, glass, steel, and paint.
Liquefied Natural Gas
Liquefying and storing associated gas is a safer and economical alternative to gas flaring. Following purification processes, liquefied natural gas can be stored for use both on an industrial scale and domestically.
Compressed Natural Gas
Compressed natural gas (CNG) refers to methane stored at high pressure. Methane derived from landfills and oil wells can be compressed at a pressure ranging between 20-25 MPa and stored in cylinders. This gas flaring alternative can be used to power vehicles which run on natural gas engines.
GENERON Can Help Reduce Flare in the Oil and Gas Industry
GENERON is dedicated to providing all customers with access to technologies needed to optimize their industrial energy production processes. With our long-term experience in the oil and gas industry, we are uniquely positioned to effectively aid our partners.
For more information about how we can help reduce flaring in the oil and gas sector, please contact our team today!