The TSA process (Temperature Swing Adsorption) process is based on adsorption at operating conditions and regeneration at an elevated temperature. The adsorption capacity of an adsorbent at higher temperature is lower than at lower temperatures. Using this physical aspect drying of gases is possible with molecular sieves. The regeneration is done by increasing the temperature of the adsorber that needs to be regenerated.
There are several possibilities to introduce the heat in to the adsorber:
- Heating ambient air,
- Heating part of the feed gas ,
- Heating part of the product gas,
- Heating a separate inert gas.
The choice for the best way of regeneration is depending on the application and the required dewpoint.
Process description of the T.S.A. (Temperature Swing Adsorption) process (SPLIT FLOW TYPE)
The systems consist of two adsorbers filled with molecular sieves, activated Alumina or sorbead material. The selection of the drying agent is depending on the required dew point, ambient conditions and type of gas to be dried.
The gas that need to be dried is fed into one of the adsorbers. First the gas is reduced to a somewhat lower pressure in order to allow the purge gas to be re-injected in the inlet. The water is adsorbed on the drying material. The gas can be dried to a dew point (at atmospheric pressure) better than -90 deg C.
The saturated adsorber is being regenerated at high temperatures of 110-280 deg C (depending on the required dewpoint, the process parameters, the gas composition and the used material). The regeneration gas is taken from the inlet of the dryer package. Part of the gas flow is split-up and the purge gas is first heated in an electric heater to the required regeneration temperature. The heated purge gas is fed counter current in to the adsorber that is being regenerated and the regeneration takes place at somewhat higher pressure than the adsorption pressure. After the purge gas leaves the regenerated adsorber, the gas is cooled in a water cooled heat exchanger and the condensed water is separated from the gas in a water separator with automatic drain. The gas is fed back to the inlet downstream the pressure control valve and is entering the TSA system again.