Study On Minimum Ignition Temperature Of Wood Dust And Its Countermeasure Of Safe Production

Wood dust is made from wood and is also associated with the wood processing industry.Wood dust in the production site has an adverse effect on people and equipment.The wood dust would be ignition by a hot surface,so it has the danger of explosion.Therefore,studying the minimum ignition temperature of wood dust is important for the safe production.In this paper,the minimum ignition temperature of wood dust and the influence factors of wood dust ignition was studied using the minimum ignition temperature of dust cloud and the minimum ignition temperature of dust layer tester,finally safety control measures of wood dust production was put forward.Specific conclusions are as follows:(1)Dispersion pressure,dust concentration,inert dust have an impact on the minimum ignition temperature of wood dust cloud.The suitable dispersion pressure for the wood dust cloud of mass30,50,100,200,300 and 500 mg is 0.1,0.1,0.1,0.1,0.2,0.3 bar respectively.With the increase of mass,the most suitable dispersion pressure is upward trend.(2)The minimum ignition temperature of wood dust cloud decreases firstly and then increases with the increase of concentration,but the increase is not much.When the dust is on fire,there is a best ignition concentration of 1.363 kg.m-3 and the most suitable dispersion pressure of 0.2 bar.The minimum ignition temperature of the wood dust cloud is 430 ℃.When the amount of inert dust is small,the inhibition effect is weak.(3)With the increase of inert powder,inert powder inhibition effect is enhanced.When the same amount is added,the inhibitory effect of NaCl is the weakest,the inhibitory effect of NH4H2PO4 is stronger than CaCO3,but with the addition of inert powder,NH4H2PO4 inhibited the effect of CaCO3.(4)Under the action of the metal heating plate,the burning of the wood flour layermainly includes two stages: the combustion initiation stage and the continuous stage.When the thickness of wood dust layer is increased from 5 mm to 27.5 mm,the minimum ignition temperature is reduced from 320 ℃ to 270 ℃,that is,within this thickness range,the minimum ignition temperature decreases with the increase of the thickness of wood dust layer.Use of Origin for the numerical fitting,the numerical results show that when the thickness is44 mm,the ignition temperature of wood dust layer is the smallest,and the smallest ignition temperature is 260 ℃.There was no significant relationship between the accumulated thickness and the maximum temperature of the wood dust layer,and even under the same conditions,the maximum ignition temperature of the wood dust layer is different and the span is large.(5)The minimum ignition temperature of wood dust cloud and wood dust layer is430 ℃ and 260 ℃ respectively.Although the wood dust layer will not explode,but the burning wood dust layer temperature can be as high as 540 ℃,so it can be used as ignition source ignition dust caused dust explosion.Therefore,the temperature of the production equipment or the hot surface of the pipe can not exceed 260 ℃ in the production site where the dust is deposited or accumulation.Wood dust in the production site has an adverse effect on human health and equipment and has a risk of explosion.Safety production is ensured through safety engineering,safety management and safety training.