Binbin Zhang

Carbon emission reduction strategies are crucial for addressing global climate change, with chemical absorption-based carbon capture technology being one of the core methods for achieving large-scale CO₂ mitigation. The current research focus in chemical absorption lies in selecting blended amine–catalyst systems and applying efficient absorption–desorption equipment. This study employs the Lattice Boltzmann Method (LBM) to simulate the catalytic CO₂ absorption process within an absorption column, obtaining data such as solution flow velocity, CO₂ absorption rate, and temperature distribution. The simulation results align well with experimental data from a continuous pilot-scale setup. Furthermore, the effects of different operating parameters and catalyst conditions on the absorption process were investigated. The findings indicate that higher catalyst volume fractions and smaller catalyst particle sizes enhance CO₂ absorption but may also lead to significant temperature rises across the column. Additionally, an optimized ternary amine–catalyst combination should be selected over a single amine to achieve superior CO₂ absorption capacity. Provided that the cyclic loading capacity is maintained, the absorbent solution flow rate should be minimized to ensure optimal absorption efficiency.

The formation of the initial slag layer during the first-time start-up serves as an essential step triggering subsequent overall slag deposition, which is critical for ensuring a safe and stable slagging process in a gasifier. The formation mechanism of the initial slag layer was analyzed in an entrained-flow gasifier. The results indicate that the formation of the initial slag layer primarily resulted from the condensation of alkali metal sulfate and chloride vapors, and the thermophoresis of these components occurs upon their formation into aerosol particles. The initial slag layer deposition rate is on the order of 10^–1 g/(m²·s), and the characteristic time for its formation is approximately on the scale of tens of minutes in the 2000 t/d coal consumption GSP gasifier. Besides, the influence of potassium and sodium content on both the initial slag layer deposition rate and the degree of deposition thickness nonuniformity varies considerably at different drying temperatures. In general, lower drying temperatures of the first-time start-up and higher alkali metal content in the feed coal promote the rapid formation of a relatively uniform initial slag layer.

The Paris Agreement and one of its goals, “carbon neutrality,” require intensive studies on CO₂ absorption and desorption processes. When searching for ways of reducing the huge energy cost of CO₂ desorption in the amine scrubbing process, the combination of blended amine with solid acid catalysts turned out to be a powerful solution in need of further investigation. In this study, the tri-solvent MEA (monoethanolamine) + EAE(2-(ethylamino)ethanol) + AMP(2-amino-2-methyl-1-propanol) was prepared at: 0.2 + 2 + 2, 0.5 + 2 + 2, 0.3 + 1.5 + 2.5 and 0.2 + 1 + 3 mol/L. The heterogeneous catalytic CO₂ desorptions were tested with five commercial catalysts: blended γ-Al₂O₃/H-ZSM-5, H-beta, H-mordenite, HND-8 and HND-580. Desorption experiments were conducted via a recirculation process with direct heating at 363 K or using temperature programming method having a range of 303–363 K. Then, the average CO₂ desorption rate, heat duty and desorption factors were studied. After comparison, the order of CO₂ desorption performance was found to be HND-8 > HND-580 > H-mordenite > Hβ > blended γ-Al₂O₃/H-ZSM-5 > no catalyst. Among the other combinations, the 0.2 + 1 + 3 mol/L MEA + EAE + AMP with HND-8 had a minimized heat duty (HD) of 589.3 kJ/mol CO₂ and the biggest desorption factor (DF) of 0.0277 × (10⁻³ mol CO₂)³/L² kJ min. This study provided a kind of tri-solvent with catalysts as an energy-efficient solution for CO₂ absorption and desorption in industrial CO₂ capture pilot plants.