Numerical study of the deep removal of R134a from non-condensable gas mixture by cryogenic condensation and de-sublimation

doi:10.1016/j.cjche.2023.02.008

Abstract

Abstract: Nowadays, the limits on greenhouse gas emissions are becoming increasingly stringent. In present research, a two-dimensional numerical model was established to simulate the deep removal of 1,1,1,2-tetrafluoroethane (R134a) from the non-condensable gas (NCG) mixture by cryogenic condensation and de-sublimation. The wall condensation method was compiled into the Fluent software to calculate the condensation of R134a from the gas mixture. Besides, the saturated thermodynamic properties of R134a under its triple point were extrapolated by the equation of state. The simulation of the steam condensation with NCG was conducted to verify the validity of the model, the results matched well with the experimental data. Subsequently, the condensation characteristics of R134a with NCG and the thermodynamic parameters affecting condensation were studied. The results show that the section with relatively higher removal efficiency is usually near the inlet. The cold wall temperature has a great influence on the R134a removal performance, e.g., a 15 K reduction of the wall temperature brings a reduction in the outlet R134a molar fraction by 85.43%. The effect of changing mass flow rate on R134a removal is mainly reflected at the outlet, where an increase in mass flow rate of 12.6% can aggravate the outlet molar fraction to 210.3% of the original. The research can provide a valuable reference for the simulation of the deep removal of various low-concentration gas using condensation and de-sublimation methods.

Key words: Numerical simulation, Greenhouse gas, Condensation, De-sublimation, Vapor deep removal, Non-condensable gas

摘要： Nowadays, the limits on greenhouse gas emissions are becoming increasingly stringent. In present research, a two-dimensional numerical model was established to simulate the deep removal of 1,1,1,2-tetrafluoroethane (R134a) from the non-condensable gas (NCG) mixture by cryogenic condensation and de-sublimation. The wall condensation method was compiled into the Fluent software to calculate the condensation of R134a from the gas mixture. Besides, the saturated thermodynamic properties of R134a under its triple point were extrapolated by the equation of state. The simulation of the steam condensation with NCG was conducted to verify the validity of the model, the results matched well with the experimental data. Subsequently, the condensation characteristics of R134a with NCG and the thermodynamic parameters affecting condensation were studied. The results show that the section with relatively higher removal efficiency is usually near the inlet. The cold wall temperature has a great influence on the R134a removal performance, e.g., a 15 K reduction of the wall temperature brings a reduction in the outlet R134a molar fraction by 85.43%. The effect of changing mass flow rate on R134a removal is mainly reflected at the outlet, where an increase in mass flow rate of 12.6% can aggravate the outlet molar fraction to 210.3% of the original. The research can provide a valuable reference for the simulation of the deep removal of various low-concentration gas using condensation and de-sublimation methods.

关键词: Numerical simulation, Greenhouse gas, Condensation, De-sublimation, Vapor deep removal, Non-condensable gas

Hongbo Tan, Boshi Shao, Na Wen. Numerical study of the deep removal of R134a from non-condensable gas mixture by cryogenic condensation and de-sublimation[J]. Chinese Journal of Chemical Engineering, 2023, 61(9): 180-191.

Hongbo Tan, Boshi Shao, Na Wen. Numerical study of the deep removal of R134a from non-condensable gas mixture by cryogenic condensation and de-sublimation[J]. 中国化学工程学报, 2023, 61(9): 180-191.

References

[1] B. Liu, Y. Zhao, Z. J. Lv, Y. B. Chen, Y. Zhang, M. N. Jia, Seasonal performance analysis of a new R134a alternative refrigerant for heat pump, J. Eng. Therm. 43 (12) (2022) 3177-3183 (in Chinese).
[2] V.E. Denny, A.F. Mills, V.J. Jusionis, Laminar film condensation from a steam-air mixture undergoing forced flow down a vertical surface, J. Heat Transf. 93 (3) (1971) 297–304.
[3] X.H. Ma, X.D. Zhou, Z. Lan, L.Y. Ming, Y. Zhang, Condensation heat transfer enhancement in the presence of non-condensable gas using the interfacial effect of dropwise condensation, Int. J. Heat Mass Transf. 51 (7–8) (2008) 1728–1737.
[4] W.J. Minkowycz, E.M. Sparrow, Condensation heat transfer in the presence of noncondensables, interfacial resistance, superheating, variable properties, and diffusion, Int. J. Heat Mass Transf. 9 (10) (1966) 1125–1144.
[5] J. W. Rose, Condensation of a vapour in the presence of a non-condensing gas, Int. J. Heat Mass Transf. 12 (2) (1969) 233–237.
[6] G.H. Tang, H.W. Hu, Z.N. Zhuang, W.Q. Tao, Film condensation heat transfer on a horizontal tube in presence of a noncondensable gas, Appl. Therm. Eng. 36 (2012) 414–425.
[7] J. Huang, J.X. Zhang, L. Wang, Review of vapor condensation heat and mass transfer in the presence of non-condensable gas, Appl. Therm. Eng. 89 (2015) 469–484.
[8] Z. Yin, Y. L. Guo, B. Sunden, Q. W. Wang, M. Zeng, Numerical simulation of laminar film condensation in a horizontal minitube with and without non-condensable gas by the VOF method, Numer. Heat Transf. A Appl. 68 (9) (2015) 958–977.
[9] Y. Gao, Numerical simulation of pure steam and steam with non-condensable gases condensation in vertical tubes, Shandong Univ., China, 2018 (in Chinese).
[10] S.H. Geng, J.J. Dang, J. Zhao, J.N. Zhang, J.L. Sun, K. Qin, Numerical simulation of convective condensation of steam with large proportion of non-condensable gas under high pressure, J. Unmanned Undersea Syst. 29 (1) (2021) 88–96 (in Chinese).
[11] A. Dehbi, F. Janasz, B. Bell, Prediction of steam condensation in the presence of noncondensable gases using a CFD-based approach, Nucl. Eng. Des. 258 (2013) 199–210.
[12] M. Punetha, S. Khandekar, A CFD based modelling approach for predicting steam condensation in the presence of non-condensable gases, Nucl. Eng. Des. 324 (2017) 280–296.
[13] L. Zhang, G. Zhang, W. Mao, Y. Zhang, J. Zhang, Experimental and numerical study on filmwise condensation of pure propane and propane/methane mixture, Int. J. Heat Mass Transf. 156 (2020) 119744.
[14] C.W. Lee, J.S. Yoo, H.K. Cho, Multi-scale simulation of wall film condensation in the presence of non-condensable gases using heat structure-coupled CFD and system analysis codes, Nucl. Eng. Technol. 53 (8) (2021) 2488–2498.
[15] F. Liu, Z.N. Sun, M. Ding, H.Z. Bian, Characteristics of helium stratification driven by steam condensation in the containment, J. Harbin Eng. Univ. 42 (12) (2021) 1786–1791 (in Chinese).
[16] D.Y. Peng, D.B. Robinson, A new two-constant equation of state, Ind. Eng. Chem. Fundam. 15 (1) (1976) 59–64.
[17] J.C. de la Rosa, L.E. Herranz, J.L. Munoz-Cobo, Analysis of the suction effect on the mass transfer when using the heat and mass transfer analogy, Nucl. Eng. Des. 239 (10) (2009) 2042–2055.
[18] R. B. Bird, W. E. Stewart, E. N. Lightfoot, Transport Phenomena. Wiley and Sons Inc., New York, United State of America, 2002.
[19] L. Chen, M. Leng, S. Ren, G. Liu, D. Wang, Application of EOS in calculation of gas and solid phase equilibrium, Contemp. Chem. Ind. 43 (6) (2014) 1121–1123, 1129 (in Chinese).
[20] E.R. Gilliland, Multicomponent rectification. Estimation of the number of theoretical plates as a function of the reflux ratio, Ind. Eng. Chem. 32 (9) (1940) 1220–1223.
[21] Inc. ANSYS, ANSYS FLUENT 14 User's Guide, 2011.
[22] M.X. Li, Z.Q. Li, M. Chen, The temperature distribution profile shape of the heat exchanger, J. Jilin Inst. Chem. Technol. 13 (3) (1996) 4 (in Chinese).
[23] X. Cheng, P. Bazin, P. Cornet, D. Hittner, J.D. Jackson, J. Lopez Jimenez, A. Naviglio, F. Oriolo, H. Petzold, Experimental data base for containment thermalhydraulic analysis, Nucl. Eng. Des. 204 (1–3) (2001) 267–284.