Flaring and Incineration - EnerFAQs

Flaring and incineration are two technologies used to combust waste gases that are unable to be processed or sold.

• Flaring is the igniting of natural gas at the end of a flare stack (a long metal tube), causing the characteristic flame associated with flaring.
• Incineration is the mixing and combusting of waste gas streams, air, and fuel in an enclosed chamber. Air and gas are mixed at a controlled rate and ignited. No flame is visible from a properly operating incinerator.

The type of emissions depends on the gas composition and combustion efficiency. For example, high-efficiency combustion ensures that nearly all methane is converted to carbon dioxide (CO₂) and water vapour. If hydrogen sulphide (H₂S) is included in the waste gas stream, nearly all the H₂S is converted to sulphur dioxide (SO₂).

If the waste gas stream contains methane and H₂S, a flare or incinerator with low combustion efficiency may emit some H₂S and methane as unburned products and other emissions, including black smoke and particulates. The minimum combustion temperature, liquid separation, and minimum heating value of the waste gas stream in AER regulations ensures that components in the waste gas, including methane and H₂S, are adequately combusted.

Emissions depend on factors such as the combustion efficiency of the technology and the heating value of the gas being combusted. Generally, the higher the combustion efficiency and heating value, the lower the effect on the environment.

Many factors can affect combustion efficiency. For example, a flare stack exposed to windy conditions may perform at a lower efficiency than a stack that operates in calm conditions. However, due to their height, flare stacks often better disperse emissions into the atmosphere in hilly or mountainous terrain than incinerators. Meanwhile, incinerators are not affected by windy conditions. A correctly operated incinerator can yield higher efficiencies through proper mixing, gas composition, retention time, and combustion temperature.

Properly designed incinerators can result in higher combustion efficiency than flares. However, incinerators can be affected by a narrow range of gas flow rates compared with flares and therefore have difficulty adequately dispersing emissions with higher H₂S concentrations in the waste gas. It is important to select the combustion technology suitable for the particular application.

Combustion efficiency, generally expressed as a percentage, is essentially the amount of methane converted to CO₂ or H₂S converted to SO₂. Hence, the more conversion of methane or H₂S that occurs, the higher the efficiency. Combustion efficiency can be affected by many factors, including waste gas composition, meteorological conditions, and operator competency.

For flares, the AER requires a minimum energy content of the gas mixture (20 megajoules per cubic metre), which results in higher combustion efficiency. For waste gas streams containing small amounts of hydrocarbons to combust efficiently, fuel gas must be added.

To ensure combustion efficiency for incinerators, the AER requires that the stack top temperature is maintained at 600°C or higher with a minimum residence time (the time the gas remains within the incinerator before being released into the atmosphere) of 0.5 seconds. Conventional incinerators are equipped with a refractory lining to help retain most of the combustion heat and control the combustion airflow into the incinerator, which can increase combustion efficiency. Some incinerators have innovative hybrid designs that do not contain refractory lining. Properly designed incinerators can achieve very high combustion efficiency.

The AER requires that all waste gas combustion technologies, including those for SO₂, be designed to comply with the Alberta Ambient Air Quality Objectives and Guidelines.

The Government of Alberta has set out acceptable minimal levels of safety and environmental protection related to air quality. These are the Alberta Ambient Air Quality Objectives and Guidelines and are among the most stringent in Canada.

The AER regulates flaring and incineration through performance and reporting requirements, permits, authorizations, and data collection as detailed in Directive 060: Upstream Petroleum Industry Flaring, Incinerating, and Venting.

The AER expects that operators developing energy resources in Alberta will strive to reduce flaring, incineration, and venting.

The AER requires that companies evaluate flaring and incineration at existing facilities and determine if the gas should be conserved. The licensee or operator is expected to consider the following:

• Are there residents in the area?
• Are there directly affected local residents with environmental or health concerns?
• Are there economic alternatives to burning the gas?
• Would clustering of flares be economically viable?
• How have environmental affects been considered in the decision to flare or incinerate?

Before planned flaring or incineration, the licensee or operator must provide 24-hour advance notice to the appropriate AER field centre, all residents within a 3-kilometre (km) radius for well tests with an H₂S content greater than 1%, or all residents within a 1.5 km radius for well tests with an H₂S content of less than 1%. Notification is not required for flaring or incineration during an emergency.

Additional “good neighbour” notification, including a notice for short-duration events, should be conducted if any persons have identified themselves as sensitive to emissions from the facility or are interested in receiving notification of planned flaring or incineration for other reasons.

The AER expects the licensee or operator to provide an information package to the public before each planned flaring or incineration. The information package must include the following:

• names and contact information, including telephone numbers of the licensee or operator and the AER field centre
• the location of the test flaring or incineration
• duration (start date and latest expected completion date)
• expected flaring or incineration volumes and rates
• information on the type of well (oil or gas) and the H₂S content of the gas to be burned

The AER expects the licensee or operator to address any concerns raised by the public before flaring or incinerating. If, after reasonable attempts, outstanding concerns remain unresolved, the operator or the public may request the assistance of the appropriate AER field centre.

If the licensee or operator has not resolved your concerns about a flaring or incineration permit, submit a statement of concern to the AER. The AER will consider the statement of concern. See EnerFAQs Expressing Your Concerns – How to File a Statement of Concern About an Energy Resource Project.

If a flaring or incineration permit is not required and the licensee or operator has not resolved your concerns, you may contact the appropriate AER field centre. AER staff will respond to the inquiry according to established procedures. The AER will determine whether all procedures for the planned event are acceptable and if the licensee or operator has complied with Directive 060, including consideration of any unique circumstances related to the flaring or incineration. If these conditions are met, the event will be allowed to proceed.

For more information on the AER and its processes or if you wish to speak to your local field centre or have questions about energy resource development in Alberta, contact the AER’s Customer Contact Centre: Monday to Friday (8:00 a.m. to 4:30 p.m.) at 1-855-297-8311 (toll free).

This document is part of the EnerFAQs series, which explains the AER’s regulations and processes relating to specific energy issues.

Each year the AER collects, compiles, and publishes a large amount of technical data and information about Alberta’s energy development and resources for use by industry and the public. This includes raw data, statistics, hearing materials, and information on regulations, policies, and decisions.

Publications may be downloaded free of charge from the AER website or made available through the Products and Services Catalogue by contacting Data & Information Services at InformationRequest@aer.ca.