Gas dehydration 

Moisture is the cause of hydrate formation and corrosion.

Withdrawn gas must therefore be dried to meet the requirements of the pipeline market. The dehydration procedure comprises mechanical and thermodynamical process steps whereby FLUXUS G is used for measuring the gas flow and FLUXUS F is used for measuring the quantity of removed water.

The final stage of the dehydration typically takes place in absorption towers, where the remaining humidity is captured by highly hygroscopic chemicals, e.g. glycols. FLUXUS® also offers the ideal solution for both liquid and gas flow measurement here. Glycol pumps can malfunction due to glycol corrosion or glycol lines can become clogged. FLUXUS F reliably monitors glycol pump functionality and therefore helps to prevent operational losses.

The US Environmental Protection Agency (EPA) estimates that 17 BCF (~ 500 mil. m³) of methane are lost each year through pump inefficiencies during dehydration: “Methane emissions are directly proportional to glycol overcirculation.” By measuring the concentration and flowrate of circulated glycol with FLEXIM’s non-intrusive technology, such methane losses can be minimized.

Application example at a natural gas storage site:

At each drilling site of natural gas, there is a gas dehydration facility separating the extracted gas from condensed and reservoir water. This task is realized by physically separating the water via pressure reduction as well as by using glycol for dehydration:

Triethylene glycol (TEG), a strong hygroscopic substance, is sprayed into the gas flow and absorbs there the residual water. Afterward, the water is distilled off and the glycol fed back into the cycle.
On such production facilities the FLUXUS ADM 7907 ultrasonic liquid flow meter is used for the flow measurement of TEG at very high pressures of 200 to 300 bars. 

The clamp-on flow measurement is independent of the process pressure. The ultrasonic transducers are simply clamped onto the pipe and do not come into contact with the toxic medium. No cutting or tapping of the pipe is needed for installation, all potential leakage sources are thus avoided.

FLUXUS overcame the folowing challenges:

• Reliable non-invasive measurement - no leakage risk
• Wear-free, condensate resistant
• No extra costs to accommodate high process pressure