高炉喷吹用潞安贫瘦煤爆炸下限与返回火焰长度的试验研究

该试验通过测定爆炸下限与返回火焰长度这两个参数来确定4种煤粉的爆炸性。爆炸下限指能使喷入一定装置中的粉尘云点燃并维持火焰传播的最小粉尘浓度,是确定粉尘爆炸性重要参数,试验室通常使用20L的爆炸装置进行测定。喷吹现场广泛采用长管式煤粉爆炸性测试仪检测煤尘引燃后产生的返回火焰长度,该长度随煤粉爆炸性的强弱而显著变化:返回火焰长度大于600 mm可认定该煤粉具有强爆炸性;在400~600 mm之间则煤粉具有中强度爆炸性;小于400 mm则煤粉具有弱爆炸性。结果表明:20 L球测得4种煤粉的爆炸下限在60~85 g/m3之间;长管式煤粉爆炸性测定仪测得4种煤粉的返回火焰长度在20~50 mm之间。由测定的返回火焰长度可知,试验所用的4种煤样均属于弱爆炸性煤种。

Experimental Study on Lower Explosion Limit and Length of Return Fire When Blasting Luan Barren Coal into Blast Furnace

The explosiveness of four kinds of coal has been determined by testing two parameters, the lower explosion limit and the length of return fire. The lower explosion limit is the minimun concentration when blasting into an installation the dust cloud could be ignited and the flame propaganda could be sustained, which is an important parameter for deten-nination of explosiveness of the dust and is often determined by 20-L explosion test equipment in laboratory. At the blasting field, a long-tube explosion testing device is widely used to detect the length of return fire after the coal powder is ignited. The lergth of flame fluctuates as the explosiveness of coal dust varies. If the length is over 600 rrrn, the coal powder could be taken as having strong explosiveness. If it is in-between 400-600 mm,it is medium explosive, k is weak explosive when the length is less than 400 mm. The result indicates that the lower explosion limit of four kinds of coal tested by 20-L equipment is in-between 60-85 g/m^3, and the lengths of return fire tested by long-tube explosion testing device are 20 to 50 mm, from which it is known that the tested four kinds of coal are of weak explosiveness.