Design of adsorption column for reclamation of methyldiethanolamine using homogeneous surface diffusion model

Abstract

A predictive simulation model was applied to design a fixed-bed adsorber for studying the removal of Total Organic Acid (TOA) anions from lean Methyldiethanolamine (MDEA) solution using Calcium Alginate Bentonite (CAB) clay hybrid composite adsorbent. Unlike other conventional techniques typically used for packed bed design, the predictive Homogeneous Surface Diffusion Model (HSDM) does not require any test column breakthrough curves a priori. Mass transfer coefficients and isotherm model parameters are provided as input data to HSDM for simulating column breakthrough curves. Various isotherm models were fitted to batch equilibrium data for TOA adsorption on CAB composite adsorbent. Based on Akaike Information Criterion (AIC), Freundlich isotherm was selected and the model parameters were obtained by non-linear regression. Film transfer coefficients and surface diffusivities were determined using appropriate empirical correlations available in the literature. HSDM predictions were first validated using lab-scale column adsorption data generated at lower residence times. The effects of dimensionless numbers (Biot and Stanton) on breakthrough times were investigated using the dimensionless HSDM system and a suitable scale-up regime (Bi& ~& 1 and St& >& 10) was established wherein the sensitivity of mass transfer parameters would be minimal. Using similitude rules on key design parameters, a pilot-scale adsorption column was designed and breakthrough curves were generated using the validated HSDM. The appropriateness of the design technique was verified by comparing the estimated breakthrough data and column design parameters with conventional scale-up and kinetic approaches.

Insight into Adsorption Kinetics of Cs+, Rb+, Co2+, and Sr2+ on a Zeolites-Based Composite: Comprehensive Diffusional Explanation and Modelling

“…In the precedent paragraph, we employed the homogeneous surface diffusion model (HSDM) for simulating Na + /M + (or 2Na + /M ++ ) exchanges in the fixed-bed column and predicting the adsorption dynamics of nuclides. In the following section, we interpret dimensionless numbers relative to column operations (Biot, B i ; Stanton, S t ; solute distribution constant, D g ) with the aim of gaining information regarding the shapes of breakthrough curves and breakthrough times, as well as the types of diffusional regimes involved [105,[108][109][110]. In this work, the dimensionless numbers B i , S t , and D g (as defined in Section 2.9) were determined from experimental adsorption results for different elements in alkali-activated brick, and their values are listed in Table 4.…”

Determination of Pore and Surface Diffusivities from Single Decay Curve in CSBR Based on Parallel Diffusion Model

“…The surface diffusion of adsorbents has been observed in many adsorbent systems [9][10][11][12]. Medved et al reviewed the surface diffusion models of various adsorbents [13].…”

Desarrollo de filtro para tratamiento de efluentes agroindustriales

“…Existen numerosos estudios de diseño de columnas, con amplios márgenes en cuanto a la relación mencionada, pero podría promediarse en que la relación H/D óptima debe oscilar en un rango de 3 a 7 (Kannan et al, 2020;Mc Cabe y Smith, 2002).…”