Cyclic Tests in Batch Mode of CO₂ Adsorption and Regeneration with Sorbent Consisting of Immobilized Amine on a Mesoporous Silica

Abstract

A series of CO2 adsorption tests were conducted in a fluidized bed vessel using an impregnated polyamine sorbent. This sorbent was cross-linked using a silyl derivative to improve its stability and hydrophobicity. The fluidization and adsorption behavior of this sorbent was characterized over a range of flows, temperatures, and CO2 concentrations. A Latin hypercube space-filling experimental design was implemented for each of three operating modes (nonreactive at ambient and flue gas temperatures, and in a reactive mode using 10–20% CO2) to evaluate hydrodynamics, thermal, and flue gas CO2 adsorption effects independently. It was found that the variable having the greatest impact on adsorption capacity was the duration of testing. The capacity degraded by about 10% over the 100 h of testing. The slope from all points in the hypercube matrix indicates the heat of adsorption is approximately 65.8 kJ/mol CO2, a value consistent with the literature.

Hierarchical calibration and validation of computational fluid dynamics models for solid sorbent-based carbon capture

“…Batch tests were first conducted in a cylindrical vessel fitted with heat exchange coils ( Figures 2 and 3) isolated from a circulating fluidized bed system designed to test the carbon capture performance of an integrated adsorber-regenerator loop [15]. The adsorption vessel was comprised of four main sections: plenum, bed (coil) area, freeboard and underflow.…”

“…The internals, flows, sensors, heat transfer system, data acquisition system, and capture efficiency calculations are described in more details by Spenik et al. [15].…”

“…The sorbent (32D1) used was a hyper-branched Mw 800 polyethyleneimine (PEI) coupled with a hydrophobicity-enhancing N-[3Trimethoxysilylpropyl] ethylenediamine (TMPED) immobilized on a silica-based substrate (PQ 2129). It was prepared according to the procedures described by Spenik et al [15] from a slurry of PEI, TMPED, and substrate in methanol using a ratio of 12-28-60 by weight. The bulk and hydrodynamic particle densities for 32D1 were 6 0.30±0.011 and 0.48±0.073 g/cm 3 , respectively as measured in packed and minimally fluidized beds using a modified Ergun Eq.…”

“…After adsorption was completed the fluid bed was regenerated by cutting off the CO2 flow and raising the temperature of the heat exchange fluid in the coils to 120°C while maintaining fluidization with humidified N2 at the desired set point. The amount of CO2 adsorbed or regenerated was determined from a balance between inlet flows and CO2 outlet concentration [15,16], which was measured using a Quantex Model 902P CO2 /O2 gas analyzer with range of 0 -100% CO2. Reacting flow tests consisted of 67 8 individual test points in a space-filling Latin Hypercube experimental design of which 51 were unique points.…”

“…Our approach begins with cold, non-reacting flow simulation for a bubbling fluidized bed followed by a hot non-reacting flow and concludes with hot reactive flow. All of the experiments involve the same sorbent with the code name "32D1" [15]. The validation process begins with multiphase flow hydrodynamics validation only, adding heat transfer before finally incorporating chemical reactions in our multiphase flow validations.…”