Unique Concept for Noise and Radiation Reduction in High-Pressure Flaring
Authors: Bussman W.R. , Knott D. 
Published: October 2008

Offshore production platforms and FPSOs strive to minimize the expensive boom or mounting structure necessary in order to limit radiation and noise generated by the flare. As facilities expand their production, the flare and boom can quickly become a bottleneck and safety consideration for the personnel on the platform. Therefore, a flare design that can significantly reduce noise and radiation is beneficial because it will permit a design with a shorter boom length. For an existing installation retrofit, it can allow a significant increase in production capacity without modifying the boom structure. Laboratory research data, full-scale flare test data and field results have confirmed that water injection can significantly reduce noise and radiation levels emitted from a production flare. The field installation is believed to be the first commercial installation of a high-pressure flare utilizing water injection. This paper will show the results gathered from a parametric study on noise and radiation reduction using the water injection method, discuss how the water injection method alters noise and radiation levels emitted from a flare and discuss the history, success and field data obtained from the first commercial installation of this type of flare. This paper will also discuss the additional reduction in radiation and noise when a high-pressure flare is mounted at an angle.

Introduction

In the oil and gas production market, it is becoming more common to find high-pressure flare designs as the preferred choice in flaring operations. As an alternative to the traditional low-pressure (LP), American Petroleum Institute (API) type designs, owner operators are utilizing the benefits that high-pressure flare designs can provide in both onshore and offshore applications. Particularly in the offshore market, high-pressure flare designs can offer economic advantages relative to the installation of the flare support structures. Boom lengths and/or structure heights can be significantly reduced with the installation of a properly designed highpressure flare.

High-pressure flares are typically designed for maximum flow conditions above critical pressure and can be generalized into two primary categories: Multiple Burner Arrays and Single Point Burner designs. Multiple Burner Arrays offer the greatest level of control over the quality and the shape of the flare flame. This control is due to the limited flow rate that is allowed to flare from each burner through the use of a staging valve control system. The staging controls consist of a number of valves that direct the flow of gas to those burners required for operation based upon the flow rates coming to the flare. Multiple Burner Arrays offer excellent turndown and minimum utility costs, however, as flaring capacities become greater, the burner array and resulting support structure can become quite large. In addition, the staging control system and corresponding valve distribution manifold can consume valuable space on a production platform. Although Multiple Burner Arrays provide a better level of control over the quality and shape of the flare flame, the Single Point designs offer the advantage of a simple, single point installation.