## 2 Materials and Methods
### Methods  
#### 2.2.1 Equipment Principle and Operation  
Design Ideas and Schemes  
The decrease of coal moisture in the furnace would lead to an increase in coal dust taken out of the waste gas, which would cause the gas transmission system resistance to increase, and the spray pipe of the primary cooler to be blocked by the lump of coal and tar. According to the low moisture coking coal into furnace problems, we start with the following objectives:  
1. Establish a new method and technology for low moisture coal into furnace. 2. The high temperature of the coking chamber needs high requirements for equipment. 3. Simplified equipment structure, easy operation. 4. Low dust emission in the coal charging process
5. Convenient feeding and continuous charging. 6. Good accumulation effect at the bottom of the coking chamber. 7. The flow of coal towards the length of the coking chamber to reduce its pressure on the furnace wall. A [PERSON]. [PERSON] et al. study showed that the cylindrical filling pipe blanking used by reducing the height of the blanking could effectively control the dust [21]. In addition, referring to the device principle and characteristics of powder pneumatic conveying, it not only reduces dust discharge and raw material waste, but is also convenient for conveying and is simple to operate [25; 26]. Due to the limitation of pipeline space, dust particles cannot escape the external space. Based on the above analysis, a high-temperature resistant cylinder inserted into the coking chamber is designed to realize low moisture content of coking coal into furnace and low dust production, the design principle is shown in Figure 3. This method requires that the charging process is fast and the guiding structure promotes the flow of coal towards the length of the coking chamber, simple structure, easy operation, convenient feeding, and continuous charging. Operating Principle and Equipment Characteristics  
The charging of coal in the new equipment mainly consists of two stages. (1) Extend the retractable cylinder from the charging hole of the furnace to the bottom of the coking chamber. (2) The coal is fed from the bottom of the coal hopper to the top of the cylinder through the screw feeder and then into the coking chamber through the cylinder blanking port. The specific operation process and principle are as follows:  
After the loader with the dried coking coal is moved above the charging hole in the coking chamber of the coke oven. Open the charging hole and the coal cylinder drop switch immediately, the charging cylinder extends from the charging hole into the coking chamber by its own weight; then start the screw feeder and feed the coking coal into the cylinder  
Figure 3: Comparison of different charging modes. (**a**) Dust escape characteristics under cylinder wall effect; (**b**) Dust escape characteristics under traditional charging method. and lead it into the bottom of the coking chamber. As the cylinder is lifted upward, the coal flows from the outlet at the bottom of the cylinder into the chamber mainly in the direction of the length of the chamber, until all ordered coal flows into the carbonization chamber, and the coal loading process is complete; at the same time, the cylinder should be taken back and the coal charging hole should be covered, this completes the charging process. The details of this operating principle in Figure 4. In the Figure, \(\rm V_{L}\) is the charging speed of coal, \(\rm V_{T}\) is the cylinder lifting speed. The equipment has the following characteristics:  
1. The coal charging system is compact and simple. 2. The bottom of the cylinder is provided with a guide plate. The coal can flow along the length of the coking chamber, reduce the pressure of coal accumulation towards the width of the furnace wall, and form a better accumulation effect; the details are in Figure 5.
3. The cylinder is a single-layer wall, a sliding block and a sliding groove are arranged between the adjacent cylinders.