Methods of Thermal Calculations for a Condensing Waste-Heat Exchanger

• Authors: Paweł Rączka , Kazimierz Wójs
• Languages of publication: EN

Abstracts

EN

The paper presents the algorithms for a flue gas/water waste-heat exchanger with and without condensation of water vapour contained in flue gas with experimental validation of theoretical results. The algorithms were used for calculations of the area of a heat exchanger using waste heat from a pulverised brown coal fired steam boiler operating in a power unit with a capacity of 900 MWe. In calculation of the condensing part, the calculation results obtained with two algorithms were compared (Colburn-Hobler and VDI algorithms). The VDI algorithm allowed to take into account the condensation of water vapour for flue gas temperatures above the temperature of the water dew point. Thanks to this, it was possible to calculate more accurately the required heat transfer area, which resulted in its reduction by 19 %. In addition, the influence of the mass transfer on the heat transfer area was taken into account, which contributed to a further reduction in the calculated size of the heat exchanger - in total by 28% as compared with the Colburn-Hobler algorithm. The presented VDI algorithm was used to design a 312 kW pilot-scale condensing heat exchanger installed in PGE Belchatow power plant. Obtained experimental results are in a good agreement with calculated values.

Keywords

EN

condensation heat recovery; calculation of the heat and mass transfer; heat exchanger; waste heat

• Publisher: De Gruyter Open
• Journal: Chemical and Process Engineering
• Year: 2014
• Volume: 35
• Issue: 4
• Pages: 447-461

Dates

published

1 - 12 - 2014

revised

11 - 3 - 2014

online

17 - 12 - 2014

accepted

24 - 7 - 2014

received

30 - 10 - 2013

Contributors

author

Paweł Rączka

• Wrocław University of Technology, Faculty of Mechanical and Power Engineering, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland

author

Kazimierz Wójs

• Wrocław University of Technology, Faculty of Mechanical and Power Engineering, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland

References

• Ball D.A., White E.L., Lux J.J., Razgaitis R., Markle R.A., 1984. Condensing heat exchanger systems for residential/commercial furnaces and boilers. Phase III, DOE Contract Number AC02-76CH00016.
• Colburn A.P., Hougen O.A., 1934. Design of cooler condensers for mixtures of vapors with noncondensing gases. Ind. Eng. Chem., 11, 1178-1182. DOI: 10.1021/ie50299a011.[Crossref]
• Hobler T., 1986. Ruch ciepła i wymienniki. 6th edition, WNT, Warszawa.
• Jeong K., Kessen M.J., Bilirgen H., Levy E.K., 2010. Analytical modeling of water condensation in condensing heat exchanger. Int. J. Heat Mass Transfer, 53, 2361-2368. DOI: 10.1016/j.ijheatmasstransfer.2010.02.004.[WoS][Crossref]
• Jia L., Peng X.F., Yan Y., Sun J.D., Li X.P., 2001. Effects of water vapor condensation on the convection heat transfer of wet flue gas in vertical tube. Int. J. Heat Mass Transfer, 44, 4257-4265. DOI: 10.1007/s00231-006-0148-0.[Crossref]
• Lee J., Kim T-J., Kim M.H., 2005. Experimental study on the heat and mass transfer of teflon-coated tubes for the latent heat recovery. Heat Transfer Eng., 26:2, 28-37, DOI: 10.1080/01457630590897079.[Crossref]
• Levy E., Bilirgen H., Jeong K., Kessen M., Samuelson Ch., Whitcombe Ch., 2008. Recovery of water from boiler flue gas. DOE Award Number DE-FC26-06NT42727.
• Liang Y., Che D., Kang Y., 2007. Effect of vapor condensation on forced convection heat transfer of moistened gas. Heat Mass Transfer, 43, 677-686. DOI: 10.1007/s00231-006-0148-0.[Crossref][WoS]
• Osakabe M., 2000. Latent heat recovery from oxygen-combustion flue gas. Energy Conversion Engineering Conference and Exhibit. Las Vegas, USA, 24-28 July 2000, 804-812. DOI: 10.1109/IECEC.2000.870877.[Crossref]
• Rączka P. Wójs K., 2014. Projektowanie kondensacyjnego wymiennika ciepła odpadowego. Rynek Energii, 111, 87-92.
• Shi X., Che D., Agnew B., Gao J., 2011. An investigation of the performance of compact heat exchanger for latent heat recovery from exhaust flue gases. Int. J. Heat Mass Transfer, 54, 606-615. DOI: 10.1016/j.ijheatmasstransfer.2010.09.009.[Crossref]
• Szulc P., Tietze T., Rączka P., Wójs K., 2013. Porównanie wybranych konstrukcji wymienników ciepła pracujących w układzie odzysku ciepła odpadowego ze spalin wylotowych (in Polish). Archiwum Energetyki, 1-4, 11-31.
• VDI-GVC Editor, 2010. VDI Heat Atlas. 2nd edition, Springer-Verlag, Berlin Heidelberg, 919-932.

Identifiers

DOI

10.2478/cpe-2014-0034