Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
ANALYSIS OF A RADIANT POROUS BURNER WITH ENERGY RECOVERY SYSTEM ATTACHED USING PREMIXED METHANE AND AIR
Submission Author:
José Alexandre de Campos , SC
Co-Authors:
José Alexandre de Campos, Roberto Wolf Francisco Jr.
Presenter: José Alexandre de Campos
doi://10.26678/ABCM.ENCIT2022.CIT22-0553
Abstract
In a radiant porous burner, the presence of the porous matrix enables a better mixture for the air and fuel present in the reactants, and causes the heat recirculation effect, which preheats the air-fuel mixture before it reaches the combustion zone, allowing the burner to achieve higher combustion rates and reaction temperatures. This effect makes the radiant porous burner capable of stable combustion under a wide variety of operating conditions, such as leaner air-fuel mixtures and different thermal loads, which makes it a good solution for use with low calorific gaseous fuels, such as synthesis gas and biogas. Thus, the objective of this study is to analyze the performance of the porous burner with the preheating of the reagents by means of a heat recovery device. The main parameters evaluated will be thermal efficiency, flame stability range and emission of pollutants. The heat exchanger will be installed on the side of the porous burner, thus taking advantage of part of the energy lost to the environment by the walls of the burner. The heat exchanger consists of a coil of copper tube installed on the side of the burner, between the porous matrix and the thermal insulation. The air-fuel mixture supplied to the burner flows through the copper tube, where it is preheated before being sent to the burner inlet. All tests will be performed using CH4 as fuel, at the same equivalence ratio of 0.55. The performance of the porous burner will be evaluated with and without the use of a heat exchanger, thus allowing to determine the real gain that can be obtained with the use of this heat exchanger. In this way, preliminary results obtained with the reagents supplied under standard conditions, temperature of 25°C and pressure of 1 atm, show a stable combustion regime for flame speeds between 6.0 cm/s and 24.0 cm/s. The radiation efficiency showed a behavior similar to that observed in other studies where there is a decrease in its values as the flame speed increases, ranging from 23.33% in the flame speed of 6.0 cm/s to 16.66% at a flame speed of 24.0 cm/sec. For emissions, an increase in CO emissions was observed with the reduction of flame speed. The results obtained with this work will allow the development of combustion systems more efficient and with lower pollutant emission rates.
Keywords
Radiant porous burner, reactants preheating, heat recovery system
