What is Gas Flaring? Learn from the Experts!

Gas flaring is a polluting method that allows oil & gas plants or refineries to control possibly volatile and extreme high-pressure variations of gases, it still remains an option due to economic, technical, regulatory, and safety reasons.

Gas flaring is a process used to combust or burn-off associated gases generated during numerous industrial operations.

This includes oil and gas recovery, petrochemical production, or landfill gas extraction. Flaring is usually required when gas is produced as a byproduct while extracting crude oil from the ground. Whether upstream, midstream, or downstream, facilities can use flares to destroy waste gases safely and efficiently.

However, the combustion process still emits some amounts of harmful Volatile Organic Compounds (VOCs). Gas flaring is a major contributor to greenhouse gas emissions, and is therefore a significant environmental concern. When it comes to flare gas composition, it can vary according to the involved processes.

In refineries, gases are often composed of variable quantities of hydrocarbons, carbon dioxide and other variable hydrocarbons. Generally, there is no fixed flare gas composition as the sources vary and are a product of different processes. It is possible to distinguish more acid gases, rich in H2S in processes like flare gas recovery systems and vapour recovery units. Finally, gas flaring activities can often generate particles, dust or contaminants.

 

 

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Why Flare Gas?

Gas flaring is a method that allows oil & gas plants or refineries to control possibly volatile and extreme high-pressure variations of gases. Though it is a source of pollution, it still remains an option due to economic, technical, regulatory, and safety reasons. Operators opt for this practice as it would be simply too expensive to try to recover the associated gases. The first reason is that trapping the gases and utilising them in a productive manner is logistically demanding and inefficient.

Oil fields are usually located in places that are difficult to access and are not able to produce consistent volumes of gases.

Thus, transporting them to where they can be utilised is a demanding process. On top of it, oil production sites are often spread over a large area, which means that capturing and utilising the associated gas can be extremely difficult. Therefore, gas flaring is still viewed as the best option. In addition to economic reasons, some countries have regulations which make the process of selling associated gases very difficult. Also, laws may not specify how associated gas should be processed, which causes legal ambiguities.

As a result, imposing penalties for gas flaring is not always an effective way of reducing this process since paying a penalty is often less expensive than capturing the gas and selling it. When it comes to safety aspects, burning any excess gas through gas flaring allows operators to manage those unpredictable situations.

Some examples are:

  • Pressure relief to prevent the risk of explosions by venting reactive & dangerous gases
  • Controlled combustion of VOCs
  • Waste product removal in refining or petrochemical production processes

How Does Gas Flaring Influence the Environment?

When talking numbers, each cubic metre of associated gas equals 2.5 kilograms of carbon dioxide emissions.

This translates to 400 million tons of CO2 emissions annually. Additionally, flaring belongs to one of the most common reasons for methane emissions, which contributes significantly to global warming. Apart from greenhouse gases like dioxide and methane, gas flaring releases black carbon (soot).

It appears to be a result of incomplete combustion efficiency of fossil fuels. Although it does not stay in the air for a long time (around a few days or weeks), black carbon has one of the largest warming effects on the atmosphere.

How to Reuse Gas Flaring?

Since gas flaring has negative effects on the environment, governments and international organisations have introduced severe limitations on it. Based on the Kyoto protocol, incentives are provided for the construction of low environmental impact plants that do not allow for the waste of a precious resource, in this case, by-product gases .

There are various valid ways of reusing these gases:

  1. Power generation – flare gas can be conveyed to gas or steam driven turbines for heat and electricity generation.
  2. Reinjection – flare gas can be reinjected into aged wells to maintain pressure and production outputs.
  3. Feedstock – once recovered the gases can be reused as raw material especially in the production of petrochemicals.
  4. Liquefaction - flare gas can be cooled to a temperature below its boiling point, and then stored and transported in its liquid phase.

GARO How the flare gas recovery works
Refinery photo

What Is Flare Gas Recovery System?

An essential component aimed at the recovery of gas flaring is the Flare Gas Recovery System (FGRS). FGRS systems are designed to capture and reuse waste gas generated from industrial operations, such as purge gas, vent gas, or valve leakages. This captured gas can then be used as fuel gas in a variety of applications.

Located upstream of the flare, FGR systems capture and recover most of the gases before they are flared. Applying an FGR System can bring numerous benefits:

  • Flare gas has a high heating value, meaning that it can be utilised as a fuel within the plant, lowering fuel costs.
  • Even with an FGR implemented, gas flaring will still need to be performed though in a limited manner for safety reasons. However, gas flaring reduction can not only extend the life of the flare tip, but also reduce the maintenance and utility costs associated with flaring.
  • FGR systems reduce the amount of smoke, thermal radiation, noise, and pollutants that are released into the atmosphere as a result of gas flaring.

Garo Liquid Ring Compressors for Flare Gas Recovery

At Garo, we have been constructing liquid ring compressors, ideal for handling gases and vapours with a high concentration of Hydrogen Sulphide (H2S) or Carbon Dioxide (CO2). Capable of reducing the amount of toxic gas released into the atmosphere, Garo’s Flare Gas Recovery Systems help operators meet their goals of reducing air pollution.

Valuable high heat gas can be recovered and used in multiple ways: as a fuel within a plant, reused as feedstock, or sold as a separate product, and at the same time, boost your facility's environmental credentials. With our latest evolution of the FGRS, WAIS (Washing Amine Integrated System), our liquid ring compressors are capable of compressing and cleaning gases simultaneously during a standard compression cycle. See our Flare Gas Recovery Systems page to discover how Garo can help you minimise gas flaring.

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