CO₂ Capture from the Tail Gas of Hydrogen Purification Unit by Vacuum Swing Adsorption Process, Using SAPO-34

Abstract

The idea of CO 2 capture was proposed through a multistep vacuum swing adsorption (VSA) process from the tail gas of a hydrogen purification unit with the composition of H 2 , 25%; CO 2 , 55%; CH 4 , 17%; CO, 1%; and N 2 , 2 mol %, using a SAPO-34 molecular sieve. The experimental isotherms and dynamic breakthrough curves were obtained on the lab scale to estimate the equilibrium and kinetic parameters of the adsorption. The VSA process was designed and simulated on the basis of dynamic adsorption−desorption mass and energy balances in the gas and solid phases. Then, the purity of the desorbed CO 2 , the recovery of CO 2 , and the productivity of the process with energy consumption were determined at the cyclic steady state condition. The operational conditions such as weight-hourly space velocity (WHSV), feed pressure, vacuum pressure, and purge to feed ratio were investigated and optimized by the method of fractional factorial design to achieve 90% CO 2 purity with more than 70% recovery. The simulation process was performed with conventional adsorbents of activated carbon (AC) and zeolite 5A and the results revealed the priority of SAPO-34 against AC and 5A for CO 2 enrichment.

Synthesis of diethyl carbonate from ethanol through different routes: A thermodynamic and comparative analysis

“…[5,6] DEC synthesis also serves the purpose of sequestration of CO 2 on which many efforts have been already reported. [7][8][9][10][11][12][13][14][15] A comparison on essential properties of all three compounds along with diesel is shown in Table 1.…”

“…It is also extensively used in lithium ion batteries as a solvent . DEC synthesis also serves the purpose of sequestration of CO 2 on which many efforts have been already reported . A comparison on essential properties of all three compounds along with diesel is shown in Table .…”

Porous aluminophosphates as adsorbents for the separation of CO2/CH4and CH4/N2mixtures – a Monte Carlo simulation study

“…While metal-organic frameworks (MOFs), being a relatively new group of highly porous adsorbents with tunable properties, have received particular attention, 3,6,7 zeolites and zeolite-like materials have also been widely studied, among them natural zeolites, 8,9 all-silica and high-silica zeolites, [10][11][12][13][14] aluminophosphate zeotypes (AlPOs), [15][16][17][18] and silicoaluminophosphate zeotypes (SAPOs). 14,[18][19][20][21][22] Focussing on AlPOs and SAPOs, the adsorption properties of a couple of frameworks have been characterised experimentally in order to evaluate their potential for use as adsorbents in CO 2 /CH 4 or CH 4 /N 2 separations. A relatively early (1997) study by Predescu et al investigated the adsorption of CH 4 , N 2 , and CO in AlPO-11 (AEL framework type 23 ), AlPO-17 (ERI), and AlPO-18 (AEI).…”

“…The CO 2 /CH 4 selectivites of the two SAPOs were in the range of 20-30, whereas that of AlPO-17 was close to 4, a difference that can be explained with the stronger interaction of CO 2 with the charged-framework SAPOs. Other SAPOs that have been investigated as potential adsorbents for the adsorption-based separation of CO 2 /CH 4 mixtures include SAPO-34 (CHA) 19,20 and DNL-6 (RHO). 21 SAPO-34 has also been studied for CH 4 /N 2 mixture separation.…”

Performance of Methanol-to-Olefins Catalytic Reactions by the Addition of PEG in the Synthesis of SAPO-34

“…SAPO-34, a silicoaluminophosphate zeolite with a large chabazite (CHA) framework structure and small 8-ring pore (0.38 nm 9 0.38 nm), has attracted great attention as a catalyst in a number of reactions, such as hydrogen purification, CO 2 /CH 4 separation, the dehydration of fructose into HMF, and the conversion of methanol-to-olefins (MTO) [8][9][10][11]. Among the reactions mentioned above, the MTO reaction plays an important role in the chemical energy industry.…”