NGL production requires carefully considered designs and precision engineering. The core components of the fractionation trains must be built to withstand various pressures, temperatures, chemical contents, and corrosive elements in order to generate ethane, propane, butane, and other useful hydrocarbons. Fractionation columns and reflux drums do a lot of that heavy lifting; however, ancillary equipment and systems are vital to keeping the NGL show going.
One such system is the custody transfer system, implemented in cases where a hydrocarbon stream is changing custody from a pipeline to a production facility. It may appear either as a skid-mounted modular unit or as specific components integrated into a feed system. A common component of the custody transfer system is an orifice or turbine flow meter, which integrates a measuring chamber, locking stator, and rotor to provide accurate flow measurements. Additional flow lines and valves may also be found in the system to isolate flows.
Heat exchanger networks represent another collection of ancillary components of the NGL plant. This includes the cooling towers and the process-to-process exchangers that shuttle energy between hot and cold process streams. These interchanges can happen between lean and rich amine solutions or glycol streams as well as at intercoolers of compressor outlet gas streams.
A fuel gas conditioning system is another ancillary tool in the NGL toolbox, providing lean fuel gas while optimizing liquids recovery. These systems also have the benefit of having a passive design that requires little maintenance and operator attention. Automatic safety systems are also vital, preventing detrimental effects such as overpressurization, liquid overflow, and excessive temperatures. This includes flares or vents for removing dangerous gasses and vapors that can’t be removed locally. Automated process shutdown systems may be utilized to prevent overspeeding or adverse temperatures in vital NGL systems.
A few other various components keep NGL plants functioning. Energy generation is a major concern at an NGL plant, with one of the most energy-intensive processes being propane refrigeration (PDF). In some cases turbine generators and compressors on site will use recovered methane to generate electricity. Additionally, water treatment, fire suppression, and steam generation systems all illuminate the necessity of water at the plant.