Effect Of Nano-MgO On The Flue Gas In A Ship Engine Room Fire

The ship engine room has poor ventilation,and the smoke has the characteristics of light-shielding,toxicity and high-temperature smoke accumulation during the fire.The presence of smoke increases the difficulty of rescue work and reduces the chances of escape.In this paper,Nano magnesium oxide is applied to fire smoke control with the goal of reducing fire smoke,cabin temperature and smoke concentration.In this thesis,the combination of experimental research and theoretical simulation was used to study the effects of Nano-MgO and flue gas.First,based on the molecular dynamics method,under the temperature?300K?with the pressure?100kPa,150kPa,200kPa,250kPa and 300kPa?and under the pressure?300kPa?with the temperature?300K,350K,400K,450K,500K?,the effect of Nano-MgO on the adsorption amount and adsorption heat of soot particles,CO₂,CO and O₂ in flue gas was simulated.Second,the dynamic adsorption process of soot particles in Nano-MgO and the distribution of different amounts of soot particles in Nano-MgO were studied.Finally,based on a 1500mm?L?×1500mm?B?×1000mm?H?closed experimental cabin platform,the change of smoke,temperature and smoke composition of the closed cabin with different vertical spray angles?30°,80°and110°?and different fuel usage?20ml,30ml and 40ml?was studied,under the condition of Nano-MgO and flue gas.Research indicates:?1?According to Material Studio software simulation,MgO has the maximum adsorption capacity for flue gas under 300kPa and 300K,and the adsorption capacity to carbon smoke particles and CO₂ is greater than that of CO and O₂.At 100kPa pressure and 300K temperature,the multi-component adsorption enhanced the adsorption to soot particles,and the adsorption capacity increased by 216.05mmol/g.The emergence of competitive adsorption reduced the adsorption capacity to gas.Due to the non-selectivity of physical adsorption,the distribution of soot particles in the Nanometer MgO pore changes from single layer to multi-layer.?2?When the fixed fuel quantity is 40ml and the vertical injection angle is 30°,the smoke change in the cabin is 3.2FSN,the maximum smoke reduction rate is51.61%,and the smoke drop value in 1min is 2.1FSN.The thermocouple temperature of No.1 is the lowest at 37.1°C at t=30s,and the change rate of temperature is 2.96%.The concentration of CO₂ and CO in the cabin decreased by 13.79%and 13.96%,respectively,and the concentration of O₂ changed little.At a small angle,the air pressure is concentrated,which increases the molecular kinetic energy,which is beneficial to the rapid adsorption of soot particles and smoke by the Nano-MgO.?3?When the fixed vertical injection angle is 30°and the fuel quantity is 20 ml,the smoke change is 2.7 FSN,and the drop rate is 61.36%.The thermocouple temperature of No.9 is the lowest at 36.5°C at t=30s.The concentration of CO₂ and CO in the cabin decreased by 11.11%and 20.68%,respectively,and the concentration of O₂ changed little.The increase in fuel quantity increases the smoke,temperature and smoke component concentration in the cabin,but the change rate of smoke,temperature and smoke composition is low,so the adsorption is more favorable under low fuel consumption conditions.?4?The decrease of smoke is mainly due to the physical adsorption between Nano-MgO and soot particles.The Nano-MgO is adsorbed on the outer surface of soot particles,causing the soot particles to sink.The adsorption effect is best when the spray angle is 30°,and the smoke,temperature,carbon dioxide concentration and carbon monoxide concentration decreased in the cabin.The increase of fuel quantity represents the increase of soot particles amount,which is not conducive to the adsorption to soot particles and smoke by Nano-MgO.