CIESC Journal ›› 2019, Vol. 70 ›› Issue (3): 969-978.doi: 10.11949/j.issn.0438-1157.20180729

• Separation engineering • Previous Articles     Next Articles

Experiment and simulation of PSA process for small oxygen generator with two adsorption beds

Tao TIAN1(),Bing LIU2,Meisheng SHI1,Yaxiong AN2,Jun MA1,Yanjun ZHANG1,Xinxi XU1(),Donghui ZHANG2()   

  1. 1. Institute of Medical Support Technology, Academy of System Engineering of Academy, Military Science of Chinese PLA, Tianjin 300161, China
    2. State Key Laboratory of Chemical Engineering, School of Chemical Engineering, Tianjin University, Tianjin 300072, China
  • Received:2018-07-04 Revised:2018-09-19 Online:2019-03-05 Published:2019-04-03
  • Contact: Xinxi XU,Donghui ZHANG E-mail:wzstiantao@163.com;xuxx1@sohu.com;donghuizhang@tju.edu.cn

Abstract:

A small two-bed pressure swing adsorption oxygen generator was designed and a series of experiments were carried out in the low-pressure cabin. The influences of structure and operating parameters were investigated simultaneously. The mathematic model of oxygen production process was established. The model was matched with the experiment results to verify the accuracy of the model. Numerical simulation and simulation researches were carried out to determine the relevant intrinsic parameters and external factors on the process of oxygen production and the effect of oxygen production. Performance of oxygen generator at different altitudes with different operating conditions, design parameters and operating parameters were studied to improve the oxygen production efficiency and reduce the manufacturing and operating costs of oxygen generator.

Key words: small pressure swing absorption, numerical simulation, model, plateau altitude, air separation, experimental validation

CLC Number: 

  • TQ 028.1

Fig.1

Apparatus for adsorption isotherm measuring"

Fig.2

N2 and O2 adsorption isotherm on LiLSX at different temperatures"

Fig.3

Diagram of two-bed PSA oxygen generation apparatus"

Table 1

Schedule for two-bed PSA process"

BedTime/s
4—90.84—90.8
1ADEDPPPURER
2PPPURERADED

Table 2

Mathematical model of bed for two-bed PSA process"

Model equationMathematical expression

mass balance

-εbDax,i?2Ci?z2+?(vgCi)?z+(εb+(1-εb)εp)?Ci?t+ρs(1-εb)?qi?t=0

Dax,i=0.73Dm,i+vgrpεb1+9.49εbDm,i2vgrp

(1)

(2)

energy balance gas phase

solid phase

bed wall

-kg?2Tg?z2+cvgvgρg?Tg?z+εbcvgρg?Tg?t+P?vg?z+hf(Tg-Ts)+4hwDb(Tg-T0)=0(3)
-ks?2Ts?z2+cpsρs?Ts?t+ρsi=1n(cpa,iqi)?Ts?t+ρsi=1nΔHi?qi?t-hf(Tg-Ts)=0(4)
kw?2Tw?z2+cpwρw?Tw?z-hw4Db(Db+Wt)2-Db2(Tg-Tw)+hamb4(Db+Wt)2(Db+Wt)2-Db2(Tw-Tamb)=0(5)
momentum balance-?P?z=150μ(1-εb)2εb3(2rpψ)2+1.75M(1-εb)ρg2rpψεb3vgvg(6)
adsorption balanceqi*=qm,ibiPi1+i=1nbiPi,bi=b0iexp(-ΔHi/RgT),-ΔHi=RgT?lnPi?Tq(7)
adsorption rate?qi?t=kLDF,i(qi*-qi)=15De,irp2(qi*-qi),De,i=εpτDk,iDm,iDk,i+Dm,i,Dk,i=97.0rpTMi(8)
puritypurityO2=0tcycleFoutyout,O2dt0tcycleFoutdt(9)
recoveryrecoveryO2=0tcycleFoutyout,O2dt0tcycleFinyin,O2dt(10)
productivityproductivityO2=36000tF/ADFoutyout,O2dt2tcyclewadsWads=ρp(1-εb)πHbRb2(11)
valveF=CV(Pin-Pout)(12)

Table 3

Physical characteristics of adsorption bed and adsorbent"

ParameterValue
Hb/m0.339
Db/m0.068
Wt/m0.001
rp/m6.0× 10-4
ρb /(kg·m-3)610.0
kw/(W·m-1·K-1)17.0
ks/(W·m-1·K-1)0.30
kg/(W·m-1·K-1)0.024
cpw /(kJ·kg-1·K-1)0.502
cps /(kJ·kg-1·K-1)0.902
cvg /(kJ·kg-1·K-1)0.758
Hamb/(W·m-2·K-1)22.3
hw/(W·m-2·K-1)10.0
hf/(W·m-2·K-1)60.0
εb0.33
εp0.53
ρw /(kg·m-3)7800
Tamb/K298.15

Table 4

Parameters of Langmuir adsorption model for N2/O2/Ar"

ParameterArN2O2
IP1/(mol·kg-1·kPa-1)1.16× 10-82.72× 10-91.16× 10-8
IP2/K140624651406
IP3/kPa-11.86× 10-61.11× 10-61.86× 10-6
IP4/K140624651406
ΔH/(kJ-1·mol-1)-13.478-24.57-13.478
cpa/(kJ·kmol?1·K?1)20.829.0629.09

Table 5

Summary of boundary conditions for each step"

Stepz=0z=L
adsorption(AD step)
Pz=0=PfeedPz=L=Poutlet
u0,inletCinlet,iz=0=u0Ci-εbDaxC?yi?z?Ci?zz=L=0
u0,inletCinletz=0=u0C?Tg?zz=L=0
u0,inletCinletcpTinertz=0=u0CcpTg-kg?Tg?z
equalization repressurization(ER step)
?Ci?zz=0=0?Ci?zz=L=0
u0z=0=0Pz=L=Poutlet
?Tg?zz=0=0?Tg?zz=L=0
equalization depressurization(ED step)
?Ci?zz=0=0u0,inletCinlet,iz=L=u0Ci-εbDaxC?yi?z
u0z=0=0u0,inletCinletz=L=u0C
?Tg?zz=0=0u0,inletCinletcpTinertz=L=u0CcpTg-kg?Tg?z
PUR(product upper gas purge step)
?Ci?zz=0=0u0,inletCinlet,iz=L=u0Ci-εbDaxC?yi?z
Pz=0=Poutletu0,inletCinletz=L=u0C
?Tg?zz=0=0u0,inletCinletcpTinertz=L=u0CcpTg-kg?Tg?z
PP(purge product gas step)

?Ci?zz=0=0

u0z=0=0

?Tg?zz=0=0

u0,inletCinlet,iz=L=u0Ci-εbDaxC?yi?z

u0,inletCinletz=L=u0C

u0,inletCinletcpTinertz=L=u0CcpTg-kg?Tg?z

Table 6

Summary of simulation and experiment results for two-bed PSA process"

Altitude

/m

Tower high/mmAdsorption time/sPore size/mm

Qout/

(L·min-1)

Purity/%Recovery/%
SimulationExperimentSimulationExperiment
200033970.95.0094.8694.3035.7335.63
300033970.95.0092.6494.0040.9541.59
400033970.95.0086.4191.8545.1648.20
500033970.95.0080.9883.7547.2448.95
300022630.95.0091.2290.0139.0438.64
300022640.95.0092.1791.8940.3740.13
300022650.95.0093.1992.3541.6641.41
300022660.95.0092.9391.4042.3641.79
300022670.95.0092.2489.4142.9741.78
500033990.64.4088.3190.5648.1149.00
500033990.74.4089.2491.5748.0548.97
500033990.84.4090.2392.9547.8048.90
500033990.94.4088.7293.1546.2148.19
500033991.04.4088.1492.0545.8747.58

Fig.4

Atmospheric pressure and feed rate of air at different altitudes"

Fig.5

Pressure variation of single cycle in tower at different altitudes"

Fig.6

Purity and recovery of O2 under different altitude"

Table 7

Material balance of O2 in CSS"

Altitude/

km

Qout/

(L·min-1)

Purity/%Recovery/%(P*/F*)/%(PO2*/FO2*)/%(W*/F*)/%(W*O2*/FO2*)/%(E*/F*)/%Composition of pressure equalization gas
0593.434.011.7452.1492.3565.969.4881.85%N2, 17.35%O2
54.493.047.89.0838.0189.0053.809.0381.02%N2, 18.11%O2

Fig.7

Concentration distribution of N2 in adsorption bed under different adsorption time"

Fig.8

Purity and recovery of O2 under different adsorption time"

Fig.9

Flushing gas flow at different time under different pore size"

Fig.10

Adsorption bed pressure at different time under different pore size"

Fig.11

Purity and recovery of O2 under different pore size"

1 卜令兵, 刘应书, 刘文海, 等. 微型变压吸附制氧与氧疗保健[J]. 低温与特气, 2005, 23(1): 5-9.
BuL B, LiuY S, LiuW H, et al. Micro pressure adsorption oxygen therapy and oxygen therapy health care[J]. Low Temperature and Specialty Gases, 2005, 23 (1): 5-9.
2 张志刚, 姜锐, 张月胜, 等. 浅谈我国变压吸附技术的进展[J]. 气体分离, 2011, 2: 14-20.
ZhangZ G, JiangR, ZhangY S, et al. A brief discussion on the progress of pressure swing adsorption technology in China [J]. Gas Separation, 2011, 2: 14-20.
3 杨雄. 微型变压吸附制氧机发展概况及存在的问题[J]. 气体分离, 2015, (3): 20.
YangX. Development of micro pressure adsorption pressure adsorption oxygen making machine and its existing problems[J]. Gas Separation, 2015, (3): 20.
4 吴其蒙. 节能型小型制氧机[J]. 气体分离, 2003, (3) : 54-56.
WuQ M. Energy saving small oxygen making machine[J]. Gas Separation, 2003, (3): 54-56.
5 活力. 小型制氧机与家庭氧疗[J]. 临床医学工程, 2001, 12: 62-63.
HuoL. Small oxygen machine and family oxygen therapy[J]. Clinical Medical Engineering, 2001, 12: 62-63.
6 崔红社, 刘应书, 乐恺, 等. 小型变压吸附制氧过程的数值模拟[J]. 深冷技术, 2004, (1): 20-23.
CuiH S, LiuY S, YueK, et al. Mathematical simulation of small PSA oxygen process [J]. Cryogenic Technology, 2004, (1): 20-23.
7 FarooqS, RuthvenD M, BonifaceH A. Numerical simulation of a pressure swing adsorption oxygen unit[J]. Medical Equipment Journal, 1998, 44(12): 2809-2816.
8 TeagueK G, EdgarT F. Predictive dynamic model of a small pressure swing adsorption air separation unit[J]. Industrial & Engineering Chemistry Research, 1999, 38(10): 3761-3775.
9 FernandezG F, KenneyC N. Modelling of the pressure swing air separation process[J]. Chemical Engineering Science, 1983, 38(6): 827-834.
10 FarooqS, RuthvenD M. Numerical simulation of a kinetically controlled pressure swing adsorption bulk separation process based on a diffusion model[J]. Chemical Engineering Science, 1991, 46(9): 2213-2224.
11 SilvaF A D, SilvaJ A, RodriguesA E. A general package for the simulation of cyclic adsorption processes[J]. Adsorption-Journal of the International Adsorption Society, 1999, 5(3): 229-244.
12 ChaiS W, KothareM V, SircarS. Rapid pressure swing adsorption for reduction of bed size factor of a medical oxygen concentrator[J]. Industrial & Engineering Chemistry Research, 2011, 50(14): 8703-8710.
13 RuthvenD M. Principles of Adsorption & Adsorption Processes[M]. New York: Wiley, 1984.
14 WuC W, KothareM V, SircarS. Model analysis of equilibrium adsorption isotherms of pure N2, O2, and their binary mixtures on LiLSX zeolite[J]. Industrial & Engineering Chemistry Research, 2014, 53(31): 12428-12434.
15 RamaR V, KothareM V, SircarS. Numerical simulation of rapid pressurization and depressurization of a zeolite column using nitrogen[J]. Adsorption-Journal of the International Adsorption Society, 2014, 20(1): 53-60.
16 RamaR V, ChaiS W, KothareM V, et al. Highlights of non-equilibrium, non-isobaric, non-isothermal desorption of nitrogen from a LiX zeolite column by rapid pressure reduction and rapid purge by oxygen[J]. Adsorption-Journal of the International Adsorption Society, 2014, 20(2/3): 477-481.
17 RamaR V, SircarS. Comparative performance of an adiabatic and a nonadiabatic PSA process for bulk gas separation—a numerical simulation[J]. AIChE Journal, 2017, 63(9): 4066-4078.
18 ChaiS W, KothareM V, SircarS. Efficiency of nitrogen desorption from LiX Zeolite by rapid oxygen purge in a pancake adsorber[J]. AIChE Journal, 2013, 59(2): 365-368.
19 ChaiS W, KothareM V, SircarS. Numerical study of nitrogen desorption by rapid oxygen purge for a medical oxygen concentrator[J]. Adsorption-Journal of the International Adsorption Society, 2012, 18(2): 87-102.
20 VemulaR R, KothareM V, SircarS. Performance of a medical oxygen concentrator using rapid pressure swing adsorption process: Effect of feed air pressure[J]. AIChE Journal, 2016, 62(4): 1212-1215.
21 ZhuX Q, LiuY S, YangX, et al. Study of a novel rapid vacuum pressure swing adsorption process with intermediate gas pressurization for producing oxygen[J]. Adsorption-Journal of the International Adsorption Society, 2016, 23(1): 1-10.
22 祝显强, 刘应书, 焦璐璐, 等. 快速真空变压吸附制氧的排放气充压过程研究[J]. 北京科技大学学报, 2015, 37(11): 1513-1519.
ZhuX Q, LiuY S, JiaoL L, et al. Study on pressurization with raffinate in a rapid vacuum pressure swing adsorption process for producing oxygen [J]. Journal of University of Science and Technology Beijing, 2015, 37(11): 1513-1519.
23 祝显强, 刘应书, 杨雄, 等. 吸附及解吸压力对快速变压吸附床内速度及循环性能的影响[J]. 北京科技大学学报, 2016, 38(7): 993-1001.
ZhuX Q, LiuY S, YangX, et al. Effect of adsorption and desorption pressure on the velocity and cycling performance of rapid pressure swing adsorption[J]. Journal of University of Science and Technology Beijing, 2016, 38(7): 993-1001.
24 杨彦钢, 丁艳宾, 马正飞, 等. 不同均压方式对PSA和VSA空分制氧过程的影响[J]. 南京工业大学学报(自科科学版), 2012, 34(4): 79-83.
YangY G, DingY B, MaZ F, et al. Effects of different pressure equalization methods on PSA and VSA processes for O2 production from air[J]. Journal of Nanjing University of Technology(Natural Science Edition), 2012, 34(4): 79-83.
25 周圆圆, 韦向攀, 张东辉. 三塔真空变压吸附富氧工艺过程模拟[J]. 化工进展, 2011, 30(S2): 263-267.
ZhouY Y, WeiX P, ZhangD H. Simulation of three-bed VPSA oxygen enrichment process[J]. Chemical Industry and Engineering Progress, 2011, 30(S2): 263-267.
26 KavithaT, KaliappanS. Equilibrium isotherms of methane onto activated carbons using a static volumetric method[J]. J. Environ. Sci. Eng., 2009, 51(3): 219-222.
27 丁兆阳, 韩治洋, 石文荣, 等. 快速变压吸附制氧动态传质系数模拟分析[J]. 化工学报, 2018, 69(2): 759-768.
DingZ Y, HanZ Y, ShiW R, et al. Analysis of dynamic effective mass transfer coefficients of rapid pressure swing adsorption process for oxygen production[J]. CIESC Journal, 2018, 69(2): 759-768.
28 LiD D, ZhouY, ShenY H, et al. Experiment and simulation for separating CO2 /N2, by dual-reflux pressure swing adsorption process[J]. Chemical Engineering Journal, 2016, 297: 315-324.
29 周言, 沈圆辉, 付强, 等. 真空变压吸附分离CH4/N2/O2实验、模拟与安评[J]. 化工学报, 2017, 68(2): 723-731.
ZhouY, ShenY H, FuQ, et al. Experiment, simulation and safety evaluation of vacuum pressure swing adsorption for CH4/N2/O2 separation[J]. CIESC Journal, 2017, 68(2): 723-731.
30 YangH W, YinC B, JiangB, et al. Optimization and analysis of a VPSA process for N2/CH4, separation[J]. Separation & Purification Technology, 2014, 134(1): 232-240.
31 BrandaniF, RouseA, BrandaniS, et al. Adsorption kinetics and dynamic behavior of a carbon monolith[J]. Adsorption-Journal of the International Adsorption Society, 2004, 10(2): 99-109.
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