Modeling and Behavior Analyses of Internal Thermally Coupled Air Separation Columns

Abstract

The internal thermally coupled air separation column (ITCASC) is a frontier of air separation energy savings research. The first principles model of the ITCASC is proposed and is based on the material balance, energy balance, and the related thermal coupling relationship which can be used for further control and design studies. The related solution procedures are given. Detailed behavior analyses are carried out. The research results reveal that the ITCASC process has the perfect separation effect and exhibits different behaviors compared to the conventional air separation column (CASC). The optimization model and the related operation optimization are further explored to gain insight on the energy saving potential of the ITCASC process. Optimization research results show that the ITCASC has about 47 % energy saving potential compared to the CASC process.

Nonlinear wave modeling and dynamic analysis of high-purity heat integrated air separation column

“…Many researchers carried on analytical research on HIDiC and gained much success [8][9][10][11][12][13][14][15][16]. Then a lot of national projects have applied this technology to the air separation and proved that the heat integrated air separation column (HIASC) could save more energy than the conventional air separation column (CASC) [17][18][19][20][21][22]. Nonetheless, the previous work by our group investigated the behavior analysis of the HIASC process and revealed that the behaviors of HIASC process was quite different compared to the CASC process [22][23][24].…”

Modeling, Characteristic Analysis and Optimization of an Improved Heat‐Integrated Air Separation Column

“…The HPC pressure of a CASC is generally between 0.53 and 0.57 MPa [6,33,35] and the HPC pressure of a HIASC can ideally drop to 0.39 MPa. In this paper, an improved HIASC structure is applied in order to reduce the HPC pressure and the energy consumption.…”

“…The condensed feed air 5 is combined with stream 4 and then goes into the HPC. The HPC generally has about 35 equilibrium stages [14,35]. Heat integration is accomplished through heat exchange at the top stages of the two columns, which leads to downward reflux flow for the HPC.…”

Nonlinear control based on wave model of high-purity heat integrated air separation column

“…[20][21][22]. These special characteristics bring many difficulties to modeling and controller design, especially for the high-purity columns [13,23,24].…”

“…These techniques include essentially thermal coupling between two simple columns where reboiler and condenser are no longer needed, and energy recovery is realized by transferring heat from the rectifying section to the stripping section [11][12][13][14]. Using this technology, the heat integrated air separation column (HIASC) could save 40% more energy than the conventional air separation column (CASC) [15][16][17][18][19][20].…”