Competitive adsorption equilibrium model with continuous temperature dependent parameters for naringenin enantiomers on Chiralpak AD column

Resin screening and process optimization for erythritol mother liquor chromatographic separation

In order to improve the utilization value of the erythritol mother liquor, the separation and purification of the erythritol mother liquor was selected in this study. The selected chromatographic separation programme for erythritol crystallizing mother liquor is as follows: Firstly, erythritol is resolved from mannitol and arabitol with DTF-01Ca (Suqing Group) resin and then mannitol is resolved from arabitol with 99Ca/320 (Dowex) resin. At the same time, the chromatographic conditions of the DTF-01Ca (Suqing Group) and 99Ca/320 (Dowex) resins were optimized, resulting in an optimal separation temperature and mobile phase flow rate of 70 °C, 10 ml/min. On this basis, a single-column chromatographic model was used to calculate the TD model parameter (N ) and the mass transfer coefficient (k m   ) of the separation of erythritol mother liquor by DTF-01Ca (Suqing Group) and 99Ca/320 (Dowex) resins. The adsorption isotherms, TD model parameter (N ) and the mass transfer coefficient (k m   ) provides data references for the design and operation of the simulated moving beds (SMB) separation system for the industrial-scale separation of erythritol crystallizing mother liquor.

Analyses of simulated moving bed with internal temperature gradients for binary separation of ketoprofen enantiomers using multi-objective optimization: Linear equilibria

Gradient operation of a simulated moving bed (SMB) can improve the separation and purification performance by adjusting adsorption strength in each individual zone according to its functional role. The feasibility of an internal temperature gradient (ITG) established by a difference between feed and desorbent temperatures for binary separation of ketoprofen enantiomers was investigated based on simultaneous optimization of purity and productivity of S-ketoprofen, the preferentially adsorbed species and desired product. ITG operation with a temperature difference of 20K has a unit productivity higher than isothermal mode by about 20%. Due to the combined effects of temperature transition and downstream dilution, concentration profile may exhibit a remarkable peak and a pattern of two-step drop in the temperature descending and ascending areas, respectively. Both areas, if properly located under optimal conditions, are favorable for unit productivity, which cannot be predicted by the direct use of triangle theory and average Henry's constants. Modifications of the SMB operations to reduce solvent consumption were also discussed based on analyses of parametric sensitivity and internal concentration profiles.

Power partial-discard strategy to obtain improved performance for simulated moving bed chromatography

A novel power partial-discard (PPD) strategy was developed as a variant of the partial-discard (PD) operation to further improve the separation performance of the simulated moving bed (SMB) process. The PPD operation varied the flow rates of discard streams by introducing a new variable, the discard amount (DA) as well as varying the reported variable, discard length (DL), while the conventional PD used fixed discard flow rates. The PPD operations showed significantly improved purities in spite of losses in recoveries. Remarkably, the PPD operation could provide more enhanced purity for a given recovery or more enhanced recovery for a given purity than the PD operation. The two variables, DA and DL, in the PPD operation played a key role in achieving the desired purity and recovery. The PPD operations will be useful for attaining high-purity products with reasonable recoveries.