Study On The Formation And Distribution Of CO From Incomplete Combustion Of Gas Within Confined Spaces

With the rapid development of urban gas in China,safety accidents caused by gas often happen,including the CO poisoning asphyxia accident due to incomplete combustion of gas under bad ventilation conditions.At present,most of the studies on CO poisoning events are based on the specific meteorological conditions,and lack of correlation analysis of combustion theory.The remaining studies on the indoor CO concentration distribution caused by incomplete combustion are mainly focused on the test that can only be carried out under certain specific conditions,so it is not universal.The subjects which study from the point of incomplete combustion mechanism,describe the combustion oxidation mechanism of hydrocarbons and the oxidation process of CO,point out that hydroxyl groups play an important role in the oxidation of CO and alkanes.Then this paper also analyzes the effect of the amount of ventilation on the incomplete combustion product and introduces the theoretical calculation method of incomplete combustion products in finite space and the principle of CO poisoning.The experiments on the formation and distribution of CO that in gas water heater in confined space and in open burner in airtight space were carried out respectively,which uses the experimental platform and instruments that are made and built by ourselves.In the first group of experiments,the effects of different smoke exhaust conditions,different load conditions and different indoor humidity atmosphere on the CO generation of the burner were compared,and the variation law of the smoke composition in the flue and the change law of the spatial atmosphere in the gas field were summarized.The following conclusions are drawn:1.The higher the load,the stronger the degree of incomplete combustion of water heater is and the more CO is generated,and the increase of CO is much more than the multiple of load increase.2.When spray water exists in the airtight chamber,the experiment shows that water and water vapor promote the complete combustion of the water heater at first.As combustion continues and O₂ is consumed,water and steam promote incomplete combustion of gas.3.The flue gas first diffuses to the upper space near the water heater,where it exchanges material and heat with the air there（where oxygen is given priority to the water heater）,then to the right and down at the same time,but is preferentially covered in the upper space.And it then cools and passes to the lower part of the house until it reaches the whole room.In the second group of experiments,in which the open burner was used to burn under the condition of full airtight and different number of holes,that the relationship between the change of O₂ content and the amount of CO production in the closed chamber was summarized,and that the changes of CO production under different pore areas are investigated.There are the following conclusions:1.When the open combustor of 2.1kW was burned in a closed space of 4.922 m³,there is a negative exponential relationship between the concentration of CO and the volume fraction of O₂ in a confined space,and the fitting function y=94715.439×e^-x/1.797-0.924is obtained.2.The larger the ventilation area,the higher the volume fraction of O₂.When the oxygen and hydroxyl groups are both insufficient and coupled together,the indoor CO concentration is linearly related to the ventilation area per unit volume and the fitting function is y=-0.48395x+9.74904.