The thoroughness of the heating regeneration of molecular sieves in air separation equipment directly affects its adsorption efficiency and the stability of the air separation system. To determine whether the heating regeneration of molecular sieves is thorough, a comprehensive evaluation is required, taking into account process parameters, equipment status, and analytical data.
Key process parameter monitoring: Regeneration temperature curve Molecular sieve regeneration typically requires heating to 200-300℃. During the heating phase, the temperature must be maintained at the set value for a certain period of time (such as 2-4 hours) to ensure that heat is fully transferred to the interior of the molecular sieve. Peak temperature during cold blow After regeneration is complete, the molecular sieve is cold-blown with a dry gas (such as air or nitrogen). The outlet temperature will initially decrease and then rise due to residual heat in the molecular sieve, forming a "peak temperature during cold blow". The peak temperature during cold blow should be close to the regeneration heating temperature (such as ≥150℃). The regeneration time is typically 6-8 hours (including heating, cold blowing, and pressure charging stages).
Outlet gas analysis: Moisture content detection, using a dew point meter or humidity sensor to monitor the dew point of the regeneration outlet gas. When the regeneration is thorough, the outlet dew point should be ≤-60℃ (corresponding to extremely low moisture content). CO₂ content detection, monitoring the CO₂ concentration at the regeneration outlet through an infrared analyzer or chromatograph. When the regeneration is thorough, the CO₂ concentration should be close to 0 ppm.
Observation of equipment operating status: When there is pressure fluctuation and incomplete regeneration, the adsorption capacity of the molecular sieve decreases, leading to pressure fluctuation or purity reduction at the inlet of the air separation equipment. The pressure difference across the molecular sieve bed, coupled with incomplete regeneration, may cause molecular sieve particles to agglomerate or increase dust, further increasing the bed pressure difference.
