Process description for the AA3 example simulation

The two-bed pressure swing adsorption (PSA) process has the following characteristics:

• We feed compressed, cooled ambient air to the two adsorber beds.

• While one bed adsorbs nitrogen to produce high-purity oxygen, the other bed regenerates, depressurizes, and vents through the vacuum blower.

• For the initial condition, all holdups consist of 100% helium.

  The following table shows the feed conditions.

  Table 1: Feed conditions

  Variable	Description	Value	UOM
  P	Pressure	200	kPa
  T	Temperature	25	°C
  z[O2]	Molar composition of oxygen	21	%
  z[N2]	Molar composition of nitrogen	78	%
  z[Ar]	Molar composition of argon	1	%
  z[He]	Molar composition of helium	0	%

  The following table shows the specifications for the adsorption beds. The beds consist of one adsorbent layer filled with alumina desiccant-grade adsorbent.

  Table 2: Adsorption bed specifications

  Variable	Description	Value	UOM
  L	Adsorber total length	35	cm
  Di	Adsorber inner diameter	3.5	cm
  thk	Adsorber wall thickness	0.35	cm

  The following table shows the cycle times for each step of the two-bed PSA process:

  Table 3: Cycle time

  Step	Time	UOM
  Pressurization	30	s
  Production	20	s
  Blowdown	30	s
  Purge	20	s
  Total	100	s