PDF Publication Title:
Text from PDF Page: 002
M. Mofarahi, E. J. Shokroo/Petroleum & Coal 55(3) 216-225, 2013 217 suitable adsorbent in designation of the PSA unit is a critical parameter. The prevalent adsorbents in oxygen production from air by PSA process are namely, zeolite 5A and zeolite 13X. In this PSA process using zeolite adsorbents, the nitrogen is adsorbed on the adsorbent and oxygen plus argon subsequently remain in the effluent gas. Zeolite is an aluminosilicate mineral which swells and evolves steam under the blowpipe. Some zeolitic crystal structures can be synthesized by hydrothermal reaction in autoclaves. A limited number of synthetic zeolites are currently used as commercial adsorbents i.e., 5A and 13X. During the progress was made on the PSA process, zeolites studies continually be looking away from the years in order to improve their quality (capacity and selectivity). For example, the improvements in this area include reduction of the inert inorganic material. [9-10]. The most important theoretical models to describe the PSA process behavior in terms of equilibrium and pore diffusion models are cited to Farooq & Ruthven [11], Farooq et al. [12], Hassan et al. [13], Ruthven & Farooq [14], Fernandez & Kenney [15], Farooq et al. [16], Farooq & Ruthven [17] and Knaebel & Hill [18]. In order to separation of oxygen from air by two-bed PSA process many theoretical and experimental works have been carried out by researchers separately using zeolite 5A and 13X, but to survey the effective zeolite in air separation is not yet compared the performance of zeolite 5A and 13X side to each other. These two types of zeolite are the common adsorbents in oxygen production from air by PSA process, but the question is, that have still not been solved, what kind of the zeolite is well suited to producing oxygen from air by PSA in the same fully conditions? Since the selection of a suitable adsorbent serves a significant role in the PSA performance, type of zeolite for the separation process is important question and we want answer to it here. The answer to this problem can be rose from a high efficiently study of these two types of adsorbent. Therefore, study of the performances of zeolite 5A and zeolite 13X to find the highly profitable zeolite in oxygen production from air by PSA process helps to get the high efficiently separation process. In this work, therefore, we were compared the performances of two types of zeolite adsorbent (zeolite 5A & 13X) in a two-bed PSA oxygen production system by mathematical modeling and numerical simulation. The six-step process used is as follows: (I) co-current feed pressurization (PR) of a partially pressurized bed by a previous pressurizing pressure equalization step (RP); (II) high-pressure adsorption (AD) step; (III) counter-current depressurizing pressure equalization (ED) step; (IV) counter-current blow down (BD) step; (V) counter-current purge with a light product (PG) step; (VI) co-current RP step. 2. Mathematical Model In order to develop a mathematical model for a PSA system the main assumptions that have been applied include: a. Gas behaves an ideal gas. b. The flow pattern is described by the axially dispersed plug-flow model. c. Adsorbing properties throughout the tower would remain constant and unchanged. d. Radial gradient is to be negligible. e. Equilibrium equations for the components of air can be expressed by three-component Langmuir-Freundlich isotherm. f. Mass transfer rate is expressed by a linear driving force equation. g. Thermal equilibrium between gas and solid phases is assumed. h. Pressure drop along the bed is calculated by the Ergun’s equation. Overall and component mass balances for the bulk phase in the adsorption bed to form the following equations are written, [19]: ∂C ∂2C ∂(C .u) ⎛1−ε ⎞ ∂q i−D i+ i +ρ.⎜ ⎟.i=0 (1) ∂tL∂z2 ∂zp⎝ε⎠∂t ∂C ∂t 2N ∂ C ∂(C.u) ⎛1−ε ⎞∑∂q −DL 2 + +ρp.⎜ ⎟. i =0 (2) ∂z ∂z ⎝ ε ⎠i=1 ∂t When the ideal gas law (Ci = yi P RTandC = P RT) is applied to eqns. (1) and (2), the component and overall mass balances can be represented as follows, [19]:PDF Image | PRESSURE SWING ADSORPTION PROCESSES FOR AIR SEPARATION WITH ZEOLITE
PDF Search Title:
PRESSURE SWING ADSORPTION PROCESSES FOR AIR SEPARATION WITH ZEOLITEOriginal File Name Searched:
pc_3_2013_javadi_221.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)