2016-10-11 17:44:31 hits:301

The Reasons for The Abnormal Appearance of Pellet Fuel (A)

When making pellet fuel with pellet machine,sometimes it may happen the condition that the pellets’ appearance is abnormal.For some inexperienced manufacturers,it is difficult to clear of faults quickly.

What abnormal conditions will happen to the pellet fuel?What are the causes for that?YUFCHINA will help you to know about that.



一、Pellets bent with many cracks on one side

This phenonemon often happens when the pellet fuel is coming out of the ring die.In production,when the cutter is far from the ring die’s surface and the edge is blunt,the pellets extruded from the die hole is touched off or torn apart rather than being cut off,so pellets would bent with many cracks on the other side.This kind of pellet fuel would break with many powder during the transportation.

Solutions:

Enlarge the ring die compression ratio,increase the compressive force of the ring die and press roll to the material so as to improve pellets’ density,hardness and intensity;

Adjust the distance and angle between the cutter and ring die’s surface;
Use sharper cutter.

二、Horizontal cracks run broadwise through the whole pellet

Cracks appear on the transverse section of the pellet.In formula,there is fluffy material containing plenty of fibre.Some fibre is longer than the diameter of the die hole.After the pellet is extruded,the fibre leaves cracks on the transverse section of the pellet with the influence of inflation.

Solutions:

Reduce the output and slowdown the speed of material passing through the die hole to intensify the density;

Improve the fragmentation of the powder,make the longest fibre shorter than one third of the pellet’s diameter.

三、Verticlal cracks appear on the pellets

There is fluffy and slightly elastic material in the formula.It absorbs water and swells in tempering and it will create vertical cracks after ring die pressing pellets because of water effect and elasticity of itself.

Solutions:

If necessary,you can adjust the formula;

Lower the moisture content after material tempering;

Reduce the output or increase the compression ratio to prolong the time the material stays in the ring die.

四、Pellets with radiate cracks

Unlike other small material which is easy to soften,some biggish particles in the pellets make it hard to fully absorb the moisture content and heat in the steam,thus causing radiate racks on the pellets during the cooling for different degree of softness.

Solutions:

Take control of the fragmentation of the powder and the evenness of the pellets;
Make material soften fully and evenly;

Prolong the cooling time.