Mass Transfer Coefficients for CO₂ Absorption into Aqueous Ammonia Using Structured Packing

Abstract

In this study, the gas phase volumetric overall mass transfer coefficients (K G a e ) for CO 2 absorption into aqueous ammonia solutions were measured to explore the mass transfer performance of a column packed with structured packing. The K G a e values were evaluated over ranges of main operating variables, that are, 1400−2300 m 3 ·m −2 ·h −1 gas flow rate, 20−39 m 3 · m −2 ·h −1 liquid flow rate, up to 8 kPa partial pressure of CO 2 , and 0.27−0.72 kmol·m −3 ammonia concentration. The results show that higher liquid loading and concentration of aqueous ammonia are beneficial to enhance the K G a e values. On the contrary, K G a e value decreases as the CO 2 partial pressure increases. The results also show that gas loading has little influence on K G a e . To allow the mass transfer data to be readily utilized, an empirical K G a e correlation for this system was developed. Finally, Simulations were made for the absorption of CO 2 into aqueous ammonia solutions by using the currently developed computational mass transfer model along with the proposed correlation for K G a e . The simulation results on the gas phase CO 2 concentration are found to be in satisfactory agreement with the experimental measurements.

Absorption of Carbon Dioxide into Aqueous Ammonia Solution using Blended Promoters (MEA, MEA+PZ, PZ+ArgK, MEA+ArgK)

“…the gas flow rate should be kept suitable value. Similar behavior was showed by Xu et al, [33] and Li et al, [51].…”

“…In the packed columns, the effective gas-liquid interfacial area (a v ) is considered as an important parameters in mass transfer for CO 2 absorption in addition to the mass transfer coefficients ( ). Therefore, the overall mass transfer coefficients can be given as follows [36,51]: -For the chemical absorption of CO 2 in a packed column and fast reaction where the mole fraction of CO 2 in equilibrium with the bulk liquid is assumed zero and the differential mass balance is given by Eq. 18…”

Review on the mass transfer performance of CO2 absorption by amine-based solvents in low- and high-pressure absorption packed columns

“…The overall conclusion of their work was that adding NH 3 to AMP and MDEA and using structured packing produced higher K GCO 2 a V values. Li, et al 72 have performed experiments for CO 2 absorption using an NH 3 solution to determine the K GCO 2 a V values in an absorber column packed with a novel structured packing with diversion windows type. The height of the absorber column and column diameter were 2.4 m (packing height: 2 m) and 0.15 m, respectively.…”

“…Their results showed that the developed correlation had an error of 9.8% when predicting experimental data. Li, et al 72 have developed the K GCO 2 a V correlation in an absorber column packing with diversion windows type in a NH 3 -CO 2 system. The correlation is based on important parameters such as the liquid ow rate (L), NH 3 concentration and CO 2 partial pressure: K G a e ¼ 0:0767ðLÞ 0:42 ðMÞ 0:495 .…”

Investigating the Advantages and Limitations of Modeling Physical Mass Transfer of CO2 on Flat Plate by One Fluid Formulation in OpenFOAM

“…The packed bed reactors facilitate high interfacial areas using either structured packings or random packings. Structured packings are found to give higher mass transfer rates [9][10][11][12]. The efficiency of a structured packing depends majorly upon micro level interactions between gas liquid immiscible phases next to packing surface.…”