Flare Metering with Optics From Blue-Sky Technology to the Real World

During a presentation at the 2006 North Sea Flow Measurement Workshop on new and current flare metering technologies, infrared and other optical methods of gas flow measurement were referred to as “blue-sky” technology. The inference was that these technologies, whilst they might have merit, probably would not be available for some time, if ever. In reality, this is far from true, as at least one vendor of such devices has developed its technology to the point that laboratory and field testing have been carried out, and more than twenty-five units have been sold and installed into operational plants. The purpose of this paper is to review the development, testing and deployment of the Photon Control Optical Flow Meter. In particular, the following topics will be addressed: 1. Overview of the technology, its various embodiments, its advantages and shortcomings, with a synopsis of a Canadian JIP under which development was carried out. 2. Presentation of results: • Flow Laboratory testing for installation effects • A variety of general Canadian onshore retrofit installations • Specific examples from the eight ConocoPhillips Canada “Real World” installations • An example using optical flare metering technology in Statoil 3. Detailed conclusions on the JIP, the gradual implementation of the new technology into the industry, with feedback from both users and regulators on being able to manage flare gas discharges. 1. STATE OF OPTICAL FLOW METERING: A REVIEW Historically, optics are less well known in the realm of gas flow measurement whereas analytical instrumentation – LIDAR, gas analyzers, etc., use the inherent features of light such as specific absorption, fluorescence or scattering which cannot be realized by any other techniques. Optical methods for measuring gas flow, or optical flow meters (OFM), use optical velocimetry, the measurement of gas flow velocity from which the volumetric flow rate can be derived. These methods can be subdivided into laser Doppler velocimeters (LDV) and optical transit time * LIDAR (Light Detection and Ranging) is an optical remote sensing technology that measures properties of scattered light to find range and/or other information of a distant target. The prevalent method to determine distance to an object or surface is to use laser pulses. Like the similar radar technology, which uses radio waves instead of light, the range to an object is determined by measuring the time delay between transmission of a pulse and detection of the reflected signal.