Hydrocarbon Dew Point Control
Hydrocarbon Dew Point Control
Low Temperature Separation (LTS) Package
LTS uses the Joule–Thomson effect. Gas cools when expanded at constant enthalpy from a higher pressure to a lower pressure. The cooling causes hydrocarbons to condense.
Process description
High-pressure gas enters a heat-exchanger coil at the bottom of the separator where the gas is cooled. A high-pressure separator removes water or condensate formed during cooling. The high-pressure gas then passes through a reducing valve where the Joule–Thomson expansion occurs. Hydrocarbon liquid drops to the bottom of the separator while the gas leaves with a dew point equal to the temperature and pressure inside the vessel. Glycol injection can be used to prevent hydrate formation if upstream dehydration has not been installed.
Major equipment
- Low Temperature Separator with integrated heating coil
- High Pressure Separator (HPKO)
- Heat Exchanger
- Expansion Valve
Mechanical Refrigeration Package
Process description
The inlet gas passes through a gas-gas heat exchanger where the gas leaving the cold separator cools the incoming stream. The gas then enters a chiller, typically a kettle-type shell-and-tube exchanger using propane as the refrigerant. From the chiller, the three-phase cold separator splits the stream into water and glycol, liquid hydrocarbon, and gas. The liquid hydrocarbon is routed to distillation towers for fractionation into individual components. The top gas returns to the gas-gas heat exchanger and then becomes the outlet gas from the plant.
Major equipment
- Gas/Gas Heat Exchanger
- Chiller
- Cold Separator
SPEC Engineering support
SPEC’s experienced engineers evaluate pressure, temperature, composition, and product goals to select the most appropriate HCDPC route for each application and to optimize NGL recovery, reliability, and compliance with gas quality specifications.