Relief / flare studies

Overview of ERCB Directive 060

What is ERCB Directive 060?

Directive 60 is formally named “Upstream Petroleum Industry Flaring, Incinerating and Venting”. The most recent edition is dated November 3, 2011. This document provides guidance to the owners, operators, designers and engineers of upstream flares, incinerators and vents. The aim is to eliminate or reduce flaring, venting and incinerating in order to ensure Alberta Ambient Air Quality Objectives (AAAQOs) are met and where required to meet health and safety objectives.

What does Directive 060 mean to me?

This section presents some high level points as described in Directive 60. Many further details are found in the actual document, and the user is advised to consult the actual Directive for more information.

How much can we vent/flare/incinerate?

Alberta as a whole has a solution gas flaring limit of 670 x 106m3 per year. Different limits apply in different situations. For example, for gas plants processing less than 1x109 m3/year of raw gas (approximately 100 MMSCFD), flaring, incinerating and venting cannot exceed 1% of raw gas in the first year and 0.5% after the first year. Pilot and flare system purges, and acid gas flares are not counted in this volume.

When can we vent/flare/incinerate?

Routine venting should never be chosen if there are sufficient gas volumes to sustain stable combustion. If there is in excess of   900 m3/day, then the operator must show that a decision tree such as those shown in Sections 2.3, 4 and 5 of Directive 60 is followed to determine the ultimate disposal of gas.

Solution gas produced on a routine basis must be conserved (not flared) when the economic evaluation (per Section 2.8 of Directive 60) results in a Net Present Value (NPV) greater than -$50,000 CDN (as determined by the method in Directive 60 Section 2.8.1), or when the flare is within 500 m of an existing residence.

Test well flaring must, in general, not exceed 72 hours, except for bitumen and coalbed methane sites. Existing gas gathering systems should be used where possible. A decision tree for temporary flaring as shown in Section 3.1 of Directive 60 must be followed.

Non-routine flaring incinerating and venting (such as in the case of an emergency) must be minimized, especially by reducing plant inlet. Reporting requirements may apply. Criteria exist that limit the number of non-routine flaring events. For example, a gas plant that processes more than 500 E3m3/d cannot have more than 6 major non-routine flaring events (>100 E3m3) in 6 months. Each day that the flare operates above that major threshold value is considered to be a major event. See Section 5 of Directive 60 for more information.

Requirements for performance and design of vents/flares/incinerators and conservation facilities.

Conservation facilities must be designed for a minimum of 95% conservation. Operators of production facilities within 3 km of each other must jointly consider clustering when evaluating gas conservation project economics. Power generation can be considered an alternative for conserving solution gas.

Dispersion modeling can be done with the ERCB’s ERCBflare.xlsand ERCBincin.xls spreadsheets, available on the ERCB website. This will help the user and the ERCB determine if there are any risks to exceeding the AAAQOs.

Venting and fugitive emissions management requirements.

Hydrocarbon liquids stored in atmospheric storage tanks that vent to atmosphere must not have a true vapour pressure greater than 83 kPaa at 21.1°C. Temporary venting of sweet, lean gas is allowed in certain circumstances (e.g. for well unloading). Venting of sour gas is not allowed and venting must not result in H2S odours outside the lease boundary nor may it result in off-site exceedances of any of the variables in the AAAQO. Benzene venting has a special classification found in Section 8.3 and in Directive 39. Venting of non-combustible gases is allowed.

Measurement and reporting requirements.

Flared, incinerated and vented gas must be reported monthly through the Petroleum Registry of Alberta, as per Directive 007.  Flaring of sour gas is reported separately as per Directive 017. All volumes of gas greater than 100 m3/month must be reported.

Meters must be installed where flare volumes (not including purge, pilot or dilution gas) exceed 500 m3/day. All acid gas flared must be metered. Estimation by engineering calculation may be allowed in lieu of metering under certain conditions and with approval by the ERCB.

Logs of flaring, incinerating and venting events must also be kept and retained for a minimum of 12 months.

How do I use Directive 060?

In design

Permits must be obtained for virtually all types of flares, incinerators and vents, as detailed in Directive 60. Sour service requires special permit attention.

Section 7 of Directive 60 prescribes combustion and conversion efficiencies, as well as minimum heating value of flared gas. A good rule of thumb is that flared gas cannot have a lower heating value less than 20 MJ/m3.

In addition, incinerators must provide a minimum residence time of 0.5 seconds at maximum flow rate or more to obtain complete combustion, and must operate with a minimum exit temperature of 600°C. Acid gas or sour gas must meet different requirements, see Section 7.1.2 for more detail.

Section 7.4 sets limits on maximum ground level radiation, typically set at 4.73 kW/m2 and various rules about height to meet dispersion requirements. Spacing of flares and incinerators is covered in Section 7.8.

During operation

If temporary flaring is required, then there is a permitting process as indicated in Section 3.3 of Directive 60. Smoke must be controlled and ignition must be reliable. Reporting protocols set out in Directive 60 must be followed at all times.

How does it relate to API STD 521?

Directive 60 is not prescriptive as to design of flares, incinerators and vents, but instead requires that API 521, Section 4, as well as other codes (fire, electrical, CSA, etc.) be used in design of flare systems and that a professional engineer or technologist be responsible for the design. Flare knock out drum requirements are mandated to follow API-521 as well and allow credit for a safety instrumented system in lieu of a flare knock out drum in certain situations.

Where do I find a copy of it?

At www.ercb.ca, under ‘Industry Zone’ click on ‘Rules, Regulations, Requirements’, then find Directives in the menu, and find Directive 060 (http://bit.ly/vKKqam). In this section, you will find the latest Directive 60, plus the ERCB’sERCBflare.xls and ERCBIncin.xls spreadsheet.


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