FAQs of Raw Materials for Briquette Press Machinery

1.Q: How many kinds of coal are there?
A: The coal can be divided into 4 kinds according to its formation time and coalification degree:

• Lignite: its appearance is brown, with relatively low coalification degree; it has high absorbent ability, and the moisture content usually can reach 20%. It has many impurities inside, so the calorific value is not high. It is easy to weather and combust spontaneously, so it is difficult for storage or long distance transportation. Therefore, it has to be processed by the briquette press machinery first, so as to be transported.
• Bituminous coal or soft coal: is the most widely distributed and largest reserved coal in nature. Its ash and moisture content is comparatively higher.
• Meager coal: also called lean coal, is difficult to burn and combust. When burning, its flame is short. Many of its physical and chemical indicators are between anthracite and bituminous coal.
• Anthracite coal: is the coal that has highest degree of coalification. Its color is grayish black, with metallic luster. It is hard, commonly known as anthracite. It hass the highest carbon content of up to 95% to 98%. When burning, it has no smoke, only a short blue flame. It has the highest calorific value.

If subdivided by the characteristics, uses and other segments, coal also has the following varieties as: lean coal, coking coal, coking coal, with coking coal, fat coal, fat coal gas, gas coal, caking coal, weakly caking coal, non-caking coal, long flame coal, etc.
2.Q: What are the ingredients of coal?
   A: The main ingredient is carbon, so when people mention coal, they refer to carbon coal. In Japan, people even call it with one word- carbon, and the coal mine is called carbon mine.
There are also other elements in coal like small amount of sulfur, aluminum, calcium, iron, silicon, hydrogen, oxygen, nitrogen and other elements, as well as some water.

3.Q: What are the volatile components of coal?
   A: When the organic matters in coal decompose by heat, they become materials that can flow with gas. During the flowing process, they continue to burn, and finally, most of them become gaseous substances, and flow out the flue.
4.Q: What is the calorific value concept of coal?
   A: It refers to the heat emitted of 1 kilogram of coal during its combustion. This heat unit is one thousand calories Bajaur, which is written (KJ). KJ is the legal unit of measurement of China; while in actual application, we often use kcal as the unit.
1 kcal = 4.1816 kJ
5.Q: How to judge the quality of coal?
   A: The high calorific value and fewer impurities are the two most common evaluations. For the coal used for special purposes, its physical and chemical properties are also need to be considered.