The company sent three different sizes of VFF positive displacement flow meters for chemical injection measurement at varying flow rates. Each was calibrated to work at different rates of flow in the chemical injection process.
The order comprised three HF40 meters, a V125 positive displacement (PD) flow meter and a VFF8 PD flow meter, all supplied to measure the flow of triethylene glycol (TEG) – high purity “lean” TEG – before it comes into contact with hydrates and “rich” TEG, which has absorbed water later in the process.
All were pressure rated to ANSI1500, constructed from 316L stainless steel, and incorporating 1.5-in. 1500 ring type joint (RTJ) wafer connections. Their flow range is 0.4-40 l/min, with a viscosity range of 0.5 to 100,000 cSt or greater, and a repeatability of +/- 0.25%.
TEG is employed as a hydrate inhibitor. The chemical is placed into contact with natural gas and strips water out of the gas. Used TEG is then heated to a high temperature and put through a condensing system that removes the water as waste and reclaims the TEG for continuous re-use within the system.
This process prevents hydrates forming in wells’ sub-surface valves under high pressure and at low temperatures during long shutdowns.
The flow meters measure the flow of TEG to ensure the correct amount is injected to prevent hydrate formation.
Litre Meters claims its flow capability has been improved by coating the pressure balance chamber and titanium rotor with physical vapor deposition (PVD), designed to lower the meter’s friction properties and to improve wear resistance.
In addition, the company recommended filtration at 100 microns in order to keep particulates out of the flow chambers of the meters, thereby assuring continual flow.