Polishing
For Gas liquefaction the required gas quality is more stringent than pipeline quality, in order to produce liquefied methane (LNG), the CO2 content needs to be under 100ppm. To this end, our ZPTS® Plant (Zeolite Pressure Temperature Swing) extracts all carbon dioxide (CO2) and moisture (H2O) through molecular sieve adsorption towers. The gas pressure is regulated at the inlet of the CO2 polishing skidand then enter into a set of modular towers, packed with zeolite that will retain these impurities.
Once saturated, the towers can be regenerated. The ZPTS is designed with enough redundant towers that operation is uninterrupted while other towers are regenerating.
This regeneration consists of 3 phases:
- Heating: in this phase desorption occurs, a reverse process to adsorption where the zeolite is heated with high-temperature gas to facilitate the separation of impurities from the zeolites.
- Vacuum: a depressurization and a series of pressure and vacuum pulses are generated that withdrawal these impurities from the towers (which can be used for power generation or other intrinsic user-end processes).
- Cooling: finally, the zeolite module is cooled, leaving the tower free from impurities and ready to return to the gas filtering operation.
This regeneration process can be carried out thanks to the presence of two NX-45 compressors integrated into the system and responsible for driving the necessary gas in the closed circuit that makes up each phase mentioned above
Additionally, it should be noted that our Plant presents its mobile version called ZPTS Trailer, which allows the equipment to be easily transported and relocated if required. Its special design with a selftransporting chassis allows the incorporation of carriages for movement and has hydraulic systems to raise it and position it quickly on location.
