In medium- and large-scale air separation units (ASUs), the molecular sieve purification system is a critical component for ensuring gas purity, but its energy consumption cannot be ignored. Currently, the system mainly uses thermal swing adsorption (TSA) for regeneration, accounting for about 5% of total energy consumption.
If high-performance molecular sieves with stronger CO₂ adsorption capacity are used, excellent adsorption performance can be maintained at higher temperatures, reducing the load on the precooling system and even lowering refrigeration demand. This not only decreases the quantity of molecular sieve required but also reduces regeneration energy consumption—achieving a dual energy-saving effect. Additional measures include:
1. Using a dual-layer bed of activated alumina and molecular sieve – lowers regeneration temperature and saves energy.
2. Adopting a staged heating–cool purge approach during regeneration – ensures thorough regeneration while shortening heating time.
3. Installing a heat accumulator in the electric heating system – supplements heat during regeneration, reducing electrical demand.
4. Using waste steam heaters – applies steam from waste heat boilers to the secondary purifier for regeneration heating, saving fuel.
5. Employing a pressure swing adsorption (PSA) system – regenerates the molecular sieve bed by depressurization without heating, offering better energy efficiency than TSA.
6. Preheating purge nitrogen with compressed air from the air compressor outlet – utilizes the elevated temperature of compressed process air to warm purge nitrogen, achieving energy savings and cooling the process air simultaneously.
Post time: Aug-11-2025