Simplifying monitoring for gas flare units

Natural gas pipeline booster compressor stations require careful monitoring, maintenance and emissions reporting to ensure the safe, efficient and environmentally compliant processing and transport of natural gas from production fields and refineries over long distances to end users. This process starts when the gas is refined and first cleaned to remove liquids, impurities and any solids that damage equipment in the transportation process or at end-user facilities.

Booster or compressor stations play an essential role in the natural gas pipeline network. Once the gas is cleaned, then it is typically compressed and sent out through the pipeline, but distance, friction, elevation differences and other factors reduce pressure and then slow the movement of the gas. Multiple pipeline compressor stations must be placed carefully along the pipeline route to maintain sufficient pressure and flow to transport the gas to end users.

Natural gas production fields, refineries and booster stations are a complex network of pipes flowing raw gas first to scrubbers, filters and then onto the compressors. There is also always some amount of waste gas that is unusable for assorted reasons, which must be flared for safety reasons and must be reported to various local, state and federal regulators who are concerned about greenhouse gas emissions (GHG) and the global warming phenomenon.

For all these reasons, from plant efficiency to plant safety to plant emissions, the measurement of gas sent to flare units is extremely important. This task requires rugged, high accuracy flow instruments featuring global safety and measurement approvals to ensure the pipeline network maintains the pressure and flow of gas to end market users.

The problem

Hoover Energy, located in Artesia, NM, develops and operates portable flare gas monitoring skid systems that report flare unit activity to ensure operators that their equipment is functioning as intended by process and plant engineers to meet all safety and environmental monitoring regulations (Figure 2). Hoover Energy specialises in gas flow and temperature measurement and related instrumentation, as well as industrial electrical equipment, communications and automation.

Hoover’s portable flare gas monitoring systems run either on full solar power or on local shore power, and in the event of a power loss on location then the skid switches seamlessly over to solar without ever shutting down. They feature sophisticated communications capabilities including SCADA monitoring. With additional IO modules, the system provides flare temperature data and indicates flare valve open/closed status. A camera also can be added to the system for full flare visualisation. In fact, they can function as a full flare reporting system.

These rugged systems are operated by Hoover Energy at multiple sites across eastern New Mexico and west Texas, as well as Wyoming. Hoover’s portable gas monitoring systems utilise thermal mass flowmeters because of their accuracy, repeatability, ease of installation and low maintenance. Thermal technology provides direct mass gas flow measurement and is among a small number of flow sensing technologies approved for this demanding application by the International Organisation for Standardisation (ISO), the American Petroleum Institute (API) and the American Gas Association (AGA).

Technicians from Hoover Energy are responsible for flare system flow monitoring and testing at multiple locations for a large compressor station facility operated by Luger Energy of Artesia, New Mexico, which serves several midstream gas processing companies including Matador and Targa. The network of pipelines feeding into the main facility is large and covers many square miles, which frequently requires Hoover Energy’s technicians to drive several hours to install its portable flare gas flow monitoring skid systems at critical process measurement points.

These measurement points, which are in various line sizes of 4, 6, 8 or 10 in., are also often near valves and elbows, which can affect gas throughput as well as accurate gas flow measurement. Flowmeters are sized according to pipeline size so that the flow sensor is located optimally within the pipe and then calibrated to the specific gas flowing in the pipeline for accurate measurement. That meant the technicians needed to know in advance the size pipe in which they would be measuring gas or risk having wasted precious travel time to the site only to find out they had brought their portable flare monitoring system with the wrong flowmeter installed.

This requirement also means that while in the field that the technicians were limited in what they could do – limited by the pipe line size and calibration of the meter they brought to the site with no flexibility to install the system in other locations with different line sizes. To solve this frustrating problem, Hoover Energy contacted ESquaredi, a manufacturer’s representative, who suggested that the ST100A Thermal Flow Meter from Fluid Components International (FCI) could help solve these issues.

Read the article online at: https://www.worldpipelines.com/special-reports/11122024/simplifying-monitoring-for-gas-flare-units/