Thermal Design Considerations and Performance Evaluation of Cryogenic Tube in Tube Heat Exchangers

Document Type: Research Article

Authors

Department of Chemistry and Chemical Engineering, Faculty of Chemical Engineering, Malek Ashtar University of Technology (MUT), Tehran, I.R. IRAN

Abstract

Heat exchangers are the most important equipment in refrigeration processes. Design and modeling of heat exchangers operating at low temperatures are different from other regular heat exchangers. This study includes two sections. In the first section, design and modeling considerations needed for evaluating the real thermal behavior of heat exchangers at low temperatures were discussed. These considerations are usually neglected by researchers who have modeled the heat exchanger at low temperatures.  In the second section, a counter current helically coiled tube in tube heat exchanger operating in hydrogen liquefier was modeled and simulated considering notes discussed in the first section. The model was validated compared with the data presented by literature. The results showed the small positive effect of longitudinal heat conduction on hydrogen liquefaction. The heat in-leak into cold fluid resulted in higher cold fluid outlet temperature and higher hot fluid outlet temperature. Simulations showed that the heat in-leak into cold fluid leads to limit the overdesign for cryogenic heat exchangers. A comparison between models with considering different assumptions was presented and showed that the result may vary significantly based on the regarded assumptions.

Keywords

Main Subjects


[1] McCarty R.D., Hord J., Roder H., "Selected Properties of Hydrogen (Engineering Design Data)", National Engineering Lab.(NBS), Boulder, CO, USA, (1981).

[2 Damle R., Atrey M., The Cool-Down Behaviour of a Miniature Joule–Thomson (J–T) Cryocooler with Distributed J–T Effect and Finite Reservoir Capacity, Cryogenics71: 47-54 (2015).

[3] Chou F.-C., Pai C.-F., Chien S., Chen J., Preliminary Experimental and Numerical Study of Transient Characteristics for a Joule-Thomson Cryocooler, Cryogenics35(5): 311-316 (1995).

[4] Tzabar N., Kaplansky A., A Numerical Cool-Down Analysis for Dewar-Detector Assemblies Cooled with Joule–Thomson Cryocoolers, Int. J. Ref., 44: 56-65 (2014).

[5] Hong Y.-J., Park S.-J., Kim H.-B., Choi Y.-D., The Cool-Down Characteristics of a Miniature Joule–Thomson Refrigerator, Cryogenics, 46(5): 391-395 (2006).

[6] Maytal B., Cool-Down Periods Similarity for a Fast Joule-Thomson Cryocooler, Cryogenics, 32(7): 653-658 (1992).

[7] Bejan A., The Concept of Irreversibility in Heat Exchanger Design: Counterflow Heat Exchangers for Gas-to-Gas Applications, J. Heat Transfer, 99(3): 374-380 (1977).

[8] Chien S.B., Chen L.T., Chou F.C., A Study on the Transient Characteristics of a Self-Regulating Joule-Thomson Cryocooler, Cryogenics, 36(12): 979-984 (1996).

[9] Ranganayakulu C., Seetharamu K., Sreevatsan K., The Effects of Longitudinal Heat Conduction
in Compact Plate-Fin and Tube-Fin Heat Exchangers Using a Finite Element Method
, Int. J. Heat Mass Transfer40(6): 1261-1277 (1997).

[10] Pacio J.C., Dorao C.A., A Review on Heat Exchanger Thermal Hydraulic Models for Cryogenic Applications, Cryogenics, 51(7): 366-379 (2011).

[11] Aminuddin M., Zubair S.M., Characterization of Various Losses in a Cryogenic Counterflow Heat Exchanger, Cryogenics, 64: 77-85 (2014).

[12] Krishna V., Spoorthi S., Hegde P.G., Seetharamu K., Effect of Longitudinal Wall Conduction on the Performance of a Three-Fluid Cryogenic Heat Exchanger with Three Thermal Communications, Int. J. Heat Mass Transfer, 62: 567-577 (2013).

[13] Gupta P.K., Kush P., Tiwari A., Second Law Analysis of Counter Flow Cryogenic Heat Exchangers in Presence of Ambient Heat-in-Leak and Longitudinal Conduction Through Wall, Int. J. Heat Mass Transfer, 50(23): 4754-4766 (2007).

[14] Nellis G., A Heat Exchanger Model that Includes Axial Conduction, Parasitic Heat Loads, and Property Variations, Cryogenics43(9): 523-538 (2003).

[15] Narayanan S.P., Venkatarathnam G., Performance of a Counterflow Heat Exchanger with Heat Loss Through the Wall at the Cold End, Cryogenics39(1): 43-52 (1999).

[16] Saberimoghaddam A., Bahri Rasht Abadi M.M., Influence of Tube Wall Longitudinal Heat Conduction on Temperature Measurement of Cryogenic Gas with Low Mass Flow Rates, Measurement, 83: 20–28 (2016).

[17] Saberimoghaddam A., Bahri Rasht Abadi M.M., Evaluation of Recuperative Tube‐in‐Tube Heat Exchanger Operating in Cryogenic Refrigeration Process: Simulation‐Based Transient Study, Asia-Pacific J. Chem. Eng., 12(1): 85–96 (2017).

[18] Saberimoghaddam A., Bahri Rasht Abadi M.M., Influence of Collector Heat Capacity and Internal Conditions of Heat Exchanger on Cool-Down Process of Small Gas Liquefier, Heat Mass Transfer, (2017).

[19] Saghatoleslami N., Sargolzaei J., Mousavi S.M., Design of the Reactor, Selection of Catalyst for Ortho to Para Hydrogen Conversion and Preliminary Design of Cryogenic System for its Liquefaction, Iran. J. Chem. Chem. Eng. (IJCCE), 23(1): 73-78 (2004).

[20] Mehrpooya M., Vatani A., Moosavian S.M.A., Optimum Pressure Distribution in Design of Cryogenic NGL Recovery Processes, Iran. J. Chem. Chem. Eng. (IJCCE), 31(3): 97-109 (2012).

[21] Gupta P., Atrey M., Performance Evaluation of Counter Flow Heat Exchangers Considering the Effect of Heat in Leak and Longitudinal Conduction for Low-Temperature Applications, Cryogenics40(7): 469-474 (2000).

[22] Xin R., Ebadian M., The Effects of Prandtl Numbers on Local and Average Convective Heat Transfer Characteristics in Helical Pipes, J. Heat Transfer119(3): 467-473 (1997).