Principals of Flaring Combustion and Ways to Minimize Emissions and Smoke Design and Case Study of a New Air Injection System for Upgrading Exisiting Flares into Smokeless Flaring
Authors: Papas Michael , Smith Scot , Zink Darton , Palfreeman Nigel 
Published: February 2011

Flaring is a volatile organic compound (VOC) combustion control process in which the undesired VOCs are piped to a remote, usually elevated, location and oxidized (burned) in an open flame using a specially designed burner tip, to their less harmful combustion products for release in the environment.

In the safe, satisfactory operation of a process plant, the flare system is the single most important element for operational or emergency relief of flammable substances in the liquid or gaseous phases. Most people see flares as simply a fire on top of a pipe that burns gases. To the public, flares often appear as a source of odour, smoke, noise, fallout and light. As a result and in addition to Global Warming concern Environmental Protection Agency (EPA) have become more active, resulting in tighter regulations on both safety and emissions control for existing and new flare systems.

This paper is intended to provide: Basic information and explains what flaring is.The state of the art in understanding flare design and emissions.Explore factors influencing flare environment and failure.Ways and steps that could mitigate flare emissions, increase smokeless flare rates and improve flare life.

In order to meet increasingly strict environmental regulations and to increase the positive public perception of their facilities, many oil, gas, and petrochemical companies are upgrading existing flares to achieve smokeless flaring of hydrocarbon gases. Many of these are utility flares and are located in the Middle East region or similar Sites, where the limited availability of steam prevents conventional smokeless steam injection systems from being utilized. Adding conventional low-pressure air-assist equipment is not an economical solution, because the large air ducting used in this type of system would require costly and time consuming modifications to the existing flare support structure. To solve this ongoing problem, Zeeco has developed a new type of air-injection system using high pressure air blowers.

A case study in this report illustrates one of the ways in which the industry has sought to increase smokeless flare operation and minimise its impacts. The new type of air-injection assist system using high pressure air blowers has been developed and this new technology represents the best value for upgrading existing flares to operate as smokeless units. This system utilizes small diameter air ducting that allows existing flare tips to be modified to operate smokelessly with minimal impact to the flare support structure and lower capital investment than a conventional air-assist system. This new system also has a much lower operating cost than a steam assisted or high pressure gas assisted system. Engineers performed extensive testing at Zeeco's research facility with a full-sized flare tip and air-injection system to optimize the amount of air required for various flowrates and gas compositions. This testing has allowed Zeeco/Petrenee to offer a customized design for nearly any application. This new technology represents the best value for upgrading existing flares to operate as smokeless units. Finally the report will describe the advantages of this new air-injection system over conventional systems and the approach design engineers used in developing and testing the technology described.