Hydrocarbon Dew Point Control

The Hydrocarbon Dew Point is the temperature at which the gaseous phase of a gas begins to cool down at a constant pressure, causing the heavier hydrocarbon components to condense. The hydrocarbon dew point relies on the combination of gas composition and pressure. In the natural gas composition, the presence of lighter hydrocarbons leads to a decrease in the hydrocarbon dew point values.

Eliminating downstream plant bottlenecks or meeting sales gas specification often requires the extraction of heavy hydrocarbons. By condensing the gas, the hydrocarbon dewpoint decreases. One of the most important techniques for condensing heavy hydrocarbons from a gas stream is Joule Thomson Expansion.

This phenomenon involves a process where a gas or liquid, under pressure P1, effortlessly moves into an area of lower pressure P2 while maintaining its kinetic energy levels. This expansion is undoubtedly irreversible by its nature. Throughout this expansion, there would be no alteration in the enthalpy.

Gas expansion and a drop in temperature are caused by the decrease in pressure through the reducing valve. The low temperature separator is responsible for retrieving fluids which include pentane, heavier components, and water. Consequently, by operating in this manner, the process can effectively manage and regulate both the dew point of hydrocarbons and water within a singular unit.

The benefits:

  • Simple and compact process
  • Ease of operation
  • Low capital cost
  • Low maintenance cost
  • Applicable to heavy hydrocarbon rich gas