Experimental Research On Transporter Character And Uniformity Of The Ash Sprayed From An L-valve For Ash Transferring

The status of our nation’s energy became increasingly intense with the rapiddevelopment of the national economy. At the same time, energy-saving andenvironmental protection has become the key problem of macro-control of our country..Therefore, it is essential to reuse the physical heat of the high temperature ash from theenergy, metallurgy and chemical field etc. The temperature of the ash usually is veryhigh, almost beyond800℃. How to safely and steadily transport this ash to the ashcooler device becomes a key problem. But, the existing transporter devices have manyquestions, such as running unsteady, regulating invalid for the ash flow rate and so on.So, it is of great important significance to study the transporter devices deeply.Because of its single structure and better controllability, and larger ash flow ratewith a small aeration, L-valve is a common non-mechanical valve widely used in theenergy and chemical field. But the transport character of L-valve for ash transferring atthe actual scene is not steady enough, and there is no report for the uniformity of the ashafter sprayed from the valve. Hence, this paper would conduct experimental study forthe transporter character and the uniformity of the ash at an L-valve for ash transferring.The bottom ash from the rotary ash cooler of a300MW plant was adopted as theexperimental material. Primarily, test the transporter character at different parameters（the structure of the valve, the parameter of the aeration and the ash particle diameter）;and the uniformity of the ash sprayed from the valve under different parameters （thestructure of the valve, the parameter of the aeration, and the height from the centre lineof the horizontal pipe to the baffle） were studied. The study results are:（1） The experiment for the transporter character①the ash flow rate increases firstly and then decreases with the growing of thesuperficial aeration velocity; And the ash flow rate decreases with the growing of thedepth ratio of aeration pipe or the average experimental ash diameter;②by means of fitting, the dimensionless correlation of the ash flow rate for a newL-valve was built: The range of application for this correlation is:The superficial aeration velocity v:4.91-24.58m.s^-1; the depth ratio of aeration pipeXL:0-0.6; the average experimental ash diameter dp:1.32-2.22mm; the temperature ofash: room temperature.（2） The experiment for the uniformity of the ash①the portion of ash at each cabin becomes more uniform as the superficialaeration velocity or the depth ratio of aeration pipe or the distance from the centre lineof the horizontal pipe to the baffle growing up;②t he range of spray ash increases as the superficial aeration velocity or the depthratio of aeration pipe growing up; when the superficial aeration velocity is low, theinfluence of the height from the centre line of the horizontal pipe to the baffle is verylittle; when the superficial aeration velocity is high, the influence of the height from thecentre line of the horizontal pipe to the baffle is much larger;③as the growing of the superficial aeration velocity or the depth ratio of aerationpipe or the distance from the centre line of the horizontal pipe to the baffle, thedeviation between the average diameter of ash at each cabin and the primary ashbecomes much larger;④as the growing of the superficial aeration velocity or the depth ratio of aerationpipe or the distance from the centre line of the horizontal pipe to the baffle, thedeviation between the distribution of a particular diameter ash and the primary ashgrows up relevantly.