Experimental Study On Flame Characteristic And Thermal Characteristic Of Oxygen-rich Air Combustion

Combustion is one uppermost method for human to get energy at present. The energy from mineral combustion is over 90% in the energy wasting all over the world, so whether the combustion process is in reason or not takes great degree on the energy using and energy wasting reducing. Saving energy is most important for China as a not rich country in energy using. Our country has improved saving energy as our basic national policy and try our best to build economical society for establishing the strategic status of energy saving. Reinforcing combustion theory and improving combustion technology is urgently as a great energy wasting country. Therefore, increasing the combustion efficiency of heat-using equipment is a significant task.Oxygen-enriched combustion is one of the latest energy saving technologies recently. The technology of oxygen-enriched combustion is called'technology of resource creativity'by developed countries for its debasing fire point, increasing velocity of combustion, promoting complete combustion, enhancing blaze temperature, reducing air displacement after burning, increasing the using of heat and decreasing air overmuch coefficient, having predominant energy saving capability.Presently, the study of oxygen-enriched combustion is not deep enough, and the study content also has some limitation. Also the study of its flame characteristic and thermal characteristics is less, especially the rule and the cause of the hot loss and efficiency change is not very clear in the condition of entire oxygen-increasing for combustion-supporting and local oxygen-increasing for combustion-supporting. All the above is affected the application and extending of the technology of oxygen-enriched combustion. The paper studied the flame characteristic and thermal characteristics of oxygen-enriched combustion by the means of experiment.Aiming at the above, the paper has done the work thereafter mainly:â‘ The paper introduced the experiment equipment more detailed. The experiment equipment was composed of combustion test bed and oxygen-enriched air feed set. We used liquefied petroleum gas as fuel and designed and made air blow inflamer and minitype gas-fired boiler to assemble combustion test bed of load and without load in this test. We made oxygen-enriched air with mixed ordinary air and oxygen in deferent proportion to study the flame characteristic and thermal characteristics of oxygen-enriched combustion with the test bed.â‘¡We use the combustion test bed without load to test the oxygen-enriched air with the oxygen in 21%-30% percent, observing and noting the change of the blaze shape, temperature field and cone angle with the oxygen content variety. The test carried through deep discussion about the test picture and data analysis applying blaze mechanism of transmission and correlative speculative knowledge.The flame characteristic of the oxygen-enriched combustion is:The blaze burning speed was increasing gradually and the blaze spread speed was accerlating, further causing the burning bone turning reduced after oxygen adding. This result led the blaze high temperature bone turning reduced, the temperature gradient turning increased, the blaze tiptop temperature turning increased, blaze intensity improvement turning enhanced.â‘¢We applied the technology of entire oxygen-increasing for combustion-su- pporting and local oxygen-increasing for combustion-supporting on gas-fired boiler using the test bed of load. Analyzing the test data, the test educed the thermal characteristics change disciplinarian of the boiler with oxygen-increasing for combustion-supporting and local oxygen-increasing for combustion-supporting.The N2 decreased gradually in exhaustsmoke, and the exhaustsmoke volume decreased gradually, and the theoretic combustion tempreture increased along with oxygen concentration adding using entire oxygen-increasing for combustion- -supporting. But, because the temperature raise of different parts in the boiler was decreasing with the tri-atom gas adding and radiation exchange enhancement. NOX, one of the main contamination after the combustion of liquefied petroleum gas, went to manifold with the oxygen increasing and combustion tempreture improving.The boiler efficiency heighten gradually with the decreasing of the exhaustsmoke loss.The efficiency of the boiler improved with the decreasing of the unburnt hot loss with local oxygen-increasing for combustion-supporting. The key of the technology of the oxygen-increasing for combustion-supporting was how to determine the oxygen-increasing place and direction. For local oxygen-increasing for combustion-supporting, it needed to carry in the place where the fuel was most insufficient and mix the airflow with the deficient smoke to exert local oxygen-increasing for combustion-supporting flow to maximum, and to debase the unburnt hot loss tofurthest in order to improve the hot efficiency.â‘£Based the technology of entire oxygen-increasing for combustion-supporti- ng and local oxygen-increasing for combustion-supporting, We need to apply oxygen-increasing for combustion-supporting in reason according to the magnitude of the boiler hot loss. When the smoke hot loss is too big, we may decrease air excessive modulus, use local oxygen-increasing for combustion-supporting or entire oxygen-increasing for combustion-supporting. When unburnt hot loss is too big, we may use local oxygen-increasing for combustion-supporting reasonably and efficiently to decrease unburnt host loss to maximum extent. When using oxygen-increasing for combustion-supporting to improve boiler efficiency, we need to consider the cost of making oxygen and equipment etc, in order to get the optimization of the oxygen-increasing for combustion-supporting.