A customer from Mexico has a lot of walnut shell, so he used it as raw material to make briquette for sale. Because walnut shells contain very little lignin, which is not strong enough to bind particles together under high temperature, the resulting solid briquette is easy to be broken at the beginning. Then our engineers instruct him to mix with 20% wood sawdust and 10% other raw material which is available and cheap price for him, adjust the thickness and angle of screw propeller to produce higher pressure. Finally, customer is very happy with the resulting qualified briquettes.