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

Abstract

Absorption of CO2 into promoted-NH3 solution utilize a packed column (1.25 m long, 0.05m inside diameter) was examined in the present work. The process performance of four different blended promoters monoethanolamine (MEA)+ piperazine (PZ), piperazine (PZ)+ potassium argininate (ArgK) and monoethanolamine +potassium argininate was compared with unpromoted-NH3 solution by evaluated the absorption rate (φ_(CO_2 )) and overall mass transfer coefficient (K_(G,CO_2.) a_v) over the operating ranges of the studied process variables (1-15Kpa initial partial pressure of CO2, 5-15 Liter/min gas flow rate, 0.25-0.85 Liter/min liquid flow rate). The results exhibit that the absorption behavior and efficiency can be enhanced by rising volumetric liquid flow rate and initial CO2 partial pressure. However, the gas flow rate should be kept at a suitable value on the controlling gas film. Furthermore, it has been observed that the (PZ+ArgK) promoter was the major species that can accelerate the absorption rate and reached almost 66.166% up to123.23% over that of the unpromoted-NH3 solution.

Carbon Dioxide Capturing via a Randomly Packed Bed Scrubber Using Primary and Poly Amine Absorbents

“…The obtained experimental results show an increase in the total gas flow rate which was led to a slight increase in K G a v value with DETA absorbent for the gas flow rate increased from 3.8408 kmol/m 2 •h to 7.6817 kmol/m 2 •h then decreased as gas flow rate exceed 7.6817 kmol/m 2 •h, this slight increase can be due to many reasons one of them is that DETA is categorized as a Polyamines, a class of potential amine absorbent; due to their unique structure of two or more amino groups inside one molecule, they have been shown to have a high kinetics and, absorption capacity making them promising absorbents for carbon dioxide capturing [42]; However, turbulent column conditions are induced by a higher gas flow rate which is more favorable to mass transfer; although to the fact that gas's detention time in the solution decreased as the gas flow rate increased; thus, the K G a v increases as the driving force between carbon dioxide and the amine is increased, where as there are more molecules of carbon dioxide available to move from the gas bulk side to the gas-liquid boundary layer [43]. The sharp decrease in K G a v value over the progression of the study with DETA absorbent when the gas flow rate exceeded 7.6817 kmol/m 2 •hr and both MEA and TETA take the same trend over the range of gas flow rate used in the test; this is because using a higher gas flow rate resulted in a lesser contact time between the gas and liquid [44]. In general, there are more carbon dioxide molecules available for absorption when the gas flow rate is increased while there is a fixed amount of free active amine; the performance of mass transfer is controlled by the liquid flow rate and the reactive amine availability in the liquid phase when the gas flow rate exceeds 7.6817 kmol/m 2 •h with DETA absorbent and with using MEA and TETA over the range of gas load used in test; thus, the overall gas coefficient is not just dependent on the gas flow rate [45].…”

Modeling of Carbon Dioxide Separation by Aqueous Ammonia Solution in a Hollow‐Fiber Membrane Contactor

“…On the other hand, different types of solvents, such as conventional amines, aqueous ammonia 10, aqueous solutions 19, acid salt 20, nanofluid 8, 21, and ionic liquid 22–24, have been used to improve the mass transfer in HFMCs. However, conventional amines have many disadvantages, such as low CO 2 removal capacity, high corrosivity, degradation in the presence of O 2 and other species present in the combustion exhaust gas, such as SO 2 and NO 2 , and elevated energy consumption in the absorption process 25, 26. On the other hand, aqueous ammonia, as a promising solvent for CO 2 capture, has been receiving increasing attention recently.…”