The representative position of the briquette press in the ball press industry is the earliest and most consolidated, because the use of coal resources in China is inseparable from the briquetting press. At present, the commonly used pulverized coal forming methods mainly include cold press forming of a binder and cold press forming without a binder.
1, with adhesive cold forming
That is, the binder is added to the pulverized coal and then press-formed. In the case where binderless molding such as bituminous coal or anthracite is difficult, the cold press forming method of the binder is generally used in the industry. At present, most of the briquettes used in China’s synthetic ammonia industry also adopt this molding method, because a suitable binder having a mass ratio of 5% to 20% is added to the pulverized coal of these coal types, and the molding pressure is applied by the action of the binder. It can be reduced to 15 to 50 MPa, so it is easy to implement industrially. However, it must be pointed out that due to the use of adhesives, the following problems will occur:
(1) Reducing the fixed carbon content of briquette, especially when using inorganic substances such as lime, cement and clay;
(2) Generally speaking, the price of the binder is higher than that of the pulverized coal. Although the amount used is small, the cost of the briquette is also increased;
(3) The binder itself needs to be treated, and it must be uniformly mixed with the pulverized coal, and later consolidated, etc., so that the molding process is increased and the process is complicated;
(4) The amount of briquette used in industry is large, and the amount of binder needs to be correspondingly large. The binder should have sufficient sources. Based on these circumstances, it is necessary to strengthen the research on the binderless molding method from a long-term perspective. Of course, applications with adhesive molding will continue to evolve.
2, no binder cold forming
That is, the pulverized coal is formed without any binder and by the action of external force. This method has been widely used in many countries to make peat and lignite briquettes as household fuels or industrial fuels. For bituminous coal and anthracite, because of their high degree of coalification, it is difficult to form a pulverized coal without adhesive. At present, the binderless molding process has not been widely used in the industry, but the research work in this area has not been interrupted in the world. The clean coal wet coal rod (wet coal rod) used in China’s synthetic ammonia industry is also an example.
Pulverized coal binderless molding does not require the addition of any binder, which not only saves a large amount of raw materials, but also maintains the carbon content of the briquette, and simplifies the molding process, etc. It is a pulverized coal molding; an important development direction.