Single stage adsorbers

With a favorable equilibrium and a high adsorption rate, the adsorption may be carried out in a single stage adsorber with packing. If, in a single stage, the desired concentration is not reached, two or more adsorption stages are connected in series. This is realized by cross or countercurrent flow of the adsorbent and the fed carrier phase. 

Hybrid Crystallization/Adsorption Process. In 1994, IFP and Chevron announced the development of a hybrid process that reportedly combines the best features of adsorption and crystallization (59,99). In this option of the Eluxyl process, the adsorbent bed is used to initially produce PX of 90—95% purity. The PX product from the adsorption section is then further purified in a small single-stage crystallizer and the filtrate is recycled back to the adsorption section. It is reported that ultrahigh (99.9+%) purity PX can be produced easily and economically with this scheme for both retrofits of existing crystallization units as well as grass-roots units. A demonstration plant was built at Chevron s Pascagoula refinery in 1994. 

In order to increase the recovery of adsorbate by adsorption, and to reduce the amount of adsorbent required to attain a specific recovery, a multistage adsorption operation can be used. In such an operation (as shown in Figure 11.3), a liquid solution is successively contacted at each stage with the adsorbent. In such a scheme, the relationship given by Equation 11.7 can be applied to each stage, with assumptions similar to the single-stage case, and the concentration ofthe adsorbate in the... 

The total amount of adsorbent is 6.7g which is significantly less than what was calculated for single-stage contact filtration. It should be noted that the minimum amount of adsorbent usage is realized when a larger amount of the adsorbent is fed to the first stage followed by the smaller amount to the second stage. 

Monoclonal antibodies (MoAb) will be separated from the supernatant of a mammalian culture by using DEAE-Sephacel as the adsorbent. The supernatant contains 100 jtg/mL of MoAb. Adsorption follows the Langmuir isotherm with Y max =116 mg of MoAb per mL of adsorbent (settled volume) and K L = 0.5 x 1(T3 mg of MoAb per mL of supernatant (Desai et al, 1987). The amount of supernatant is 1 L. If you use 2 mL of DEAE-Sephacel for a single-stage, what percent of the MoAb will be recovered ... 

In Fig. 9.4-1 a single stage is depicted. The completely regenerated solid adsorbent is denoted by (or Sr for a stream) and the pure carrier fluid by (or Gr for a flow rate). In the stage the loading Xg of the Sr stream is increased to the loading X, whereas the loading Eg of the gas flow Gr is reduced to T,. The balance of the substance transferred from the fluid to the solid phase can be written as follows ... 

Single Stage Adsorption in a Vessel Adsorber with Adsorbent Packing... 

The schematic diagram for a single-stage adsorption is shown in Fig. 15.11. The solution to be treated contains V dm water, and the pollutant concentration is reduced from Q to C<., mg solute per gram of solution. The amount of adsorbent added is Af g of adsorbate free solid, and the solute concentration on the adsorbent increases from to q i mg solute per gram adsorbent. If fresh adsorbent is used, q = 0. The mass balance equates the solute removed from the liquid to that picked up by the solid. 

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