A1 is the highest quality grade and is suitable for high-end markets such as power generation, heating and industrial applications. 

characteristics:

(1) The pellet shape is regular, with a diameter of 6 mm or 8 mm;

(2) Humidity is less than 10%;

(3) Ash content is less than 0.7%

(4) Sulfur content less than 0.03%;

(5) Density greater than 600 kg/m3.

A2 is the second highest quality grade and is suitable for markets such as home heating and small industrial applications. 

characteristics: (1) regular particle shape with a diameter of 6 mm or 8 mm;

(2) Humidity is less than 10%;

(3) Ash content is less than 1.5%

(4) Sulfur content less than 0.03%:

(5) Density greater than 600 kg/m3.

B is the lowest quality grade and is suitable for some special applications, such as animal mattresses and soil conditioners. 

The following features:

(1) The pellet shape is regular, with a diameter of 6 mm or 8 mm;

(2) Humidity below 25%;

(3) Ash content is less than 3%;

(4) Sulfur content less than 0.5%;

In conclusion,biomass pellet is classified into 3 grade A1,A2,B. you figure out what grade do you use?