Sorbents for air prepurification in air separation

Rege, Salil U.; Yang, Ralph T.; Buzanowski, Mark A

doi:10.1016/s0009-2509(00)00122-6

Cited by 148 publications

(138 citation statements)

References 21 publications

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“…This finding confirmed that 13X is a microporous molecular sieve (Lillo, 2005;Rege et al, 2000). The adsorption capacity of CO 2 on zeolite 13X is large as a result of the strong adsorption capacity of micropores and capillary condensation in the mesopores.…”

Section: Texture Properties Of 13xsupporting

confidence: 64%

Desorption characteristics and kinetic parameters determination of molecular sieve by thermogravimetric analysis/differential thermogravimetric analysis technique

Guo

Zhang

Liu

2018

Adsorption Science & Technology

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The kinetics of the thermal desorption of CO 2 adsorbed on zeolite 13X were obtained using a differential thermogravimetric analyser under two different carrier gas conditions. The varying heating rates were set as 8, 12, 16, and 20 K min À1, respectively. The desorption activation energy of the physisorption sites for this experiment evaluated by an integral method without prediction of the reaction order ranged from 12.15 to 14.12 kJ mol À1 (CO 2 as the carrier gas) and 43.32 to 50.42 kJ mol À1 (Ar as the carrier gas), respectively. The desorption activation energy of the chemisorption sites ranged from 57.95 to 58.53 kJ mol À1 (CO 2 as the carrier gas) and 74.02 to 79.92 kJ mol À1 (Ar as the carrier gas), respectively.

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Section: Texture Properties Of 13xsupporting

confidence: 64%

Desorption characteristics and kinetic parameters determination of molecular sieve by thermogravimetric analysis/differential thermogravimetric analysis technique

Guo

Zhang

Liu

2018

Adsorption Science & Technology

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“…Thereafter, with the relation: q iso (0.37) = 1.16 E were calculated the isosteric heat of adsorption ( Table 5). The results reported indicated that the tested modified zeolites shows similar values for the measured isosteric heat of adsorption; but greater than those value of the isosteric heat of adsorption reported also in the present paper for the ZSM-5 zeolite, also larger than those reported for a particle packing silica and a dealuminated Y zeolite (DAY) [34], Cd, Zn and Ni-nitroprussides [41] and Cu-nitroprusside [40] and a Ni-MOF [39] (Table 6), as well bigger than experimental isosteric adsorption heats measured for the adsorption carbon dioxide on MCM-41- [58], silicalite [59], Na clinoptilolite and K-clinoptilolite [60], Na-A [61] and Na-X and MOF-5 [62] and MOF-508b [63], but similar to measured isosteric heats of adsorption for the adsorption of carbon dioxide on sodium ferrerite (Na-FER) [64]. The previously described adsorption data indicated that the interaction of the carbon dioxide molecule with the modified zeolites is strong.…”

Section: Resultsmentioning

confidence: 85%

Study of the Adsorption Space of Modified Clinoptilolites

Rolando¹,

Roque-Malherbe²,

Alba³

et al. 2013

JMSE-B

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Carbon dioxide (CO 2 ) adsorption is an important adsorbent characterization method and a significant industrial process. In separation and recovery technology, the adsorption of the CO 2 is important to reduce the concentration of this gas considered as one of the greenhouse gases. Natural zeolites, particularly clinoptilolite, are widely applied as adsorbents. In this regard, in the present research, the structure, composition and morphology of modified with hexafluorosilicate (HFSi) and orthophosphoric acid (H 3 PO 4 ) clinoptilolites were investigated by characterizations and measurements made with, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDAX) and gravimetric adsorption. Additionally, the surface Chemistry of the modified clinoptilolites was analyzed by applying diffuse reflectance fourier transform infrared spectrometry (DRIFTS). Further, the interaction of CO 2 within the adsorption space of these modified clinoptilolites and a synthetic ZSM-5 zeolite was studied with the help of adsorption measurements. After all, an appropriate theoretical methodology for the analysis of the XRD and adsorption data was applied. The calculated cell parameters of the tested are similar to those reported for a typical clinoptilolite of: a = 17.662 Ǻ, b = 17.911 Ǻ, c = 7.407 Ǻ and β = 116.40 The resolution of the TGA derivative profiles indicated the presence of two steps for water release, one of them represents the loss of majority of the water present in the micropores. This was evidenced as a broad peak centered at about 50 0 C for the CSW-HFSi-0.1, but at 100 °C for the samples CSW-HFSi-0.4. The SEM micrographs corresponding to the modified clinoptilolites, was evidenced that the CSW zeolite shows secondary particles exhibiting diameters from 3 to 40 μm, formed by primary clinoptilolite crystallites showing a crystallite size, Φ = 40 nm. The EDAX elemental analysis it can be demonstrated that the exchange process replaced about 85% of the charge compensating ions. The DRIFT spectra of the modified clinoptilolites, specifically, CSW-HFSi-0.1, show a narrow band at about: 3,740 cm -l corresponding to terminal silanol groups (Si-OH) and a band 3,600-3,650 cm -1 resulting from extra-framework Al-OH. With the precision of the measured micropore volumes related to the excellent fitting of the adsorption data by the D-R isotherm equation, it can be affirm that carbon adsorption took only place in the micropore region. The isosteric heat of adsorption calculated for the modified clinoptilolites was greater than those values reported of ZSM-5 zeolite, particle packing silica, dealuminated Y zeolite (DAY) Cd, Zn and Ni-nitroprussides and Cu-nitroprusside and a Ni-MOF. With the obtained result it can be concluded that the modified clinoptilolites with HFSi showed a quality as adsorbent comparable to commercial synthetic zeolites.

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“…The heat of adsorption for both adsorption and desorption processes was determined by the Clausius-Clapeyron equation [30]: The adsorption equilibria of selected adsorbent-adsorbate pair were sourced from available literature [21,23] Other assumptions, specific for models considered in the paper, were described in detail below, in the sections dedicated to each model.…”

Section: Modeling Of the Sorption Columnmentioning

confidence: 99%

“…The major adsorbates used are water, ammonia, and methanol. Conventional adsorbents are: zeolite molecular sieves [21], silica gel [22], alumina and active carbon [23]. Most new adsorbents are based on modification of existing one [21], to increase the adsorption capacity and to improve the heat and mass transfer.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Analytical and Numerical Models of Adsorber/desorber of Silica Gel-water Adsorption Heat Pump

Zwarycz-Makles¹,

Szaflik²

2017

J. sustain. dev. energy water environ. syst.

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In the paper, comparison of an analytical and a numerical model of silica gel/water adsorber/desorber is presented. Adsorber/desorber as a part of the two-bed single-stage adsorption heat pump is discussed. The adsorption heat pump under consideration consists of an evaporator, two adsorber/desorber columns and a condenser. Only heat and mass transfer was taken into account during operation of assumed adsorption heat pump. Adsorption equilibrium was described by the Dubinin-Astachov model. The presented mathematical models, both analytical and numerical, were created to describe the temperature, heat and concentration changes in the adsorber/desorber and consequently to describe the performance of the adsorption heat pump. Heat and mass transfer equations of the model were solved analytically and calculation parameters were entered in the common spreadsheet. The numerical model was established comprising of the set of heat and mass balance partial differential equations, together with the initial and boundary conditions and was solved by the numerical method of lines. The developed analytical model is very basic and can be used only for the initial estimates of mean cyclic temperature of the cooling/heating water in the adsorber/desorber bed. Validation of the numerical model shows reasonable agreement between the numerical and experimental averaged bed temperatures and is an indication of the proper mathematical modeling and the accuracy of the numerical analysis.

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Sorbents for air prepurification in air separation

Cited by 148 publications

References 21 publications

Desorption characteristics and kinetic parameters determination of molecular sieve by thermogravimetric analysis/differential thermogravimetric analysis technique

Desorption characteristics and kinetic parameters determination of molecular sieve by thermogravimetric analysis/differential thermogravimetric analysis technique

Study of the Adsorption Space of Modified Clinoptilolites

Comparison of Analytical and Numerical Models of Adsorber/desorber of Silica Gel-water Adsorption Heat Pump

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