Flow and Concentration Measurement during Gas Dehydration

Flow and Concentration Measurement during Gas Dehydration

Moisture is the cause of hydrate formation and corrosion within pipelines. Withdrawn gas must therefore be dried to meet the requirements of the pipeline market. The dehydration procedure comprises mechanical and thermodynamically process steps whereby FLUXUS G is used for measuring the (wet) gas flow rates and FLUXUS F is used for measuring the quantity of removed water.

The final stage of the dehydration process typically takes place in absorption towers, where the remaining humidity is captured by highly hygroscopic chemicals, e.g. glycols.
FLEXIM offers the ideal solution for both liquid and gas flow measurement at these process steps as well as for monitoring the concentration levels of the drying agent (glycol):

Glycol pumps can malfunction due to glycol corrosion or the lines simply become clogged - FLUXUS reliably monitors glycol pump functionality and therefore helps to prevent operational losses.
By employing FLEXIM's PIOX R Process Refractometer the glycol concentration levels are accurately determined and the correct dosaging and drying rate be controlled in real time.

Application example at a natural gas storage site:

At each storage site, there is a gas dehydration facility separating the extracted gas from condensed and reservoir water. This task is realized by first physically separating the water via pressure reduction as well as later by using glycol for dehydration in the absorption towers. Here, triethylene glycol (TEG), a strong hygroscopic substance, is sprayed into the gas flow and absorbs the residual water. Afterwards, the water is distilled off and the glycol fed back into the cycle.
On such production facilities the non-invasive FLUXUS flow meter is used for the flow measurement of TEG at very high pressures of 3000 to 4500 psi. 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.

Additionally, the PIOX R Process Refractometer measures the concentration levels of the glycol circulating in the towers and provides the storage operators with the relevant infomations for a proper process conrol.

Advantages:

  • Accurate and reliable non-invasive water and gas flow measurement - no leakage risk, pressure independent
  • Wear-free, condensate resistant - no maintenance required, no process shut downs for installation
  • Accurate concentration determination of the drying agent via Process Refractometry

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