Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
ENERGY AND EXERGY ANALYSIS OF A STEADY STATE THREE STEPS FIRE TUBE BOILER OPERATING WITH NATURAL GAS
Submission Author:
Florian Alain Yannick Pradelle , RJ
Co-Authors:
Vanessa Bautista, José Alberto Reis Parise, Paul Ortega, Florian Alain Yannick Pradelle
Presenter: Florian Alain Yannick Pradelle
doi://10.26678/ABCM.ENCIT2022.CIT22-0218
Abstract
The firetube boiler market has required increasing customized designs from manufacturers. In this work, the main objective is the development and the validation of a numerical simulator to perform an energy and exergy analysis of a steady state three passes firetube boiler production capacity of 1000 kg/hr, with working pressure between 1 and 10 bar, with non-submerged turn boxes and fueled with Bolivian natural gas. The impact on the temperature profile of various correlations for convective heat transfer was assessed. A central composite design was also performed to simultaneously evaluate the impact of six design or operating parameters (diameter of the tubes; boiler length; number of tubes in the second and third passes; excess of air in the mixture) and obtain an empirical second-order polynomial model in order to maximize boiler energy and exergetic efficiencies and reduce irreversibilities. A mesh test was also performed and the model was also validated with data obtained experimentally, observing the model is sensitive to the impact of working pressure and the difference between the experimental and theoretical values of the temperatures of the first and second passes. With the robust polynomial models given by the design of experiments approach, it was possible to define the most significant parameters, both for energy and exergetic efficiencies, as well as for exergy destruction. In decreasing order of importance of linear impacts, the excess of air; length of the boiler; the number and the diameter of tubes in the second and third passes and the diameter of the tube in the first pass were significant through linear contributions and some interaction terms. In addition, it was possible to quantify the trade-off between the increase of the heat exchange area and the reduction of flow turbulence level.
Keywords
Thermodynamics, Combustion., design of experiments, Tube bundles, Heat transfer
