# Effect of Furnace Structure on Burden Distribution and Gas Flow in Sinter Vertical Cooling Furnace
## 1 Introduction  
The energy consumption of the sintering process in China accounts for about 10-15% of the entire iron and steel industry, which is about 19% higher than the global level reported in Refs. [1, 2]. One of the main reasons is that the recovery rate of waste heat is low during the sintering process, at only about 40% in Ref. [3]. The sintering waste heat includes the waste heat of flue gas and the sensible heat of sinter, in which sinter sensible heat accounts for about 70% of the waste heat of the whole sintering process, which is the focus pointof sintering waste heat recovery. At present, the sensible heat recovery of sinter is mainly carried out in the ring cooler; thus, it is inevitable that there are a few disadvantages, such as a large amount of air leakage, unorganized discharge of dust, and low sensible heat recovery. In view of these shortcomings and inspired by the coke dry quenching process in Ref. [4], some scholars put forward the sinter vertical cooling process [5; 6], which has entered the stage of engineering tests. However, from the available engineering test results, because the sinter particle size distribution reaches a wide range of 0-150 mm, the sinter in a vertical cooling furnace can easily form a segregation distribution, resulting in a large amount of cooling gas escaping from the short-circuit channel, which reduces the gas-solid heat transfer efficiency in the furnace. Therefore, it is necessary to study how to weaken the \"short-circuit\" airflow. 1. The existing research on sinter vertical cooling furnace has mainly focused on the pressure drop characteristics of cooling gas in such a furnace [7; 8; 9; 10], gas-solid heat transfer characteristics [11; 12; 13; 14], and operation parameter optimization [15; 16; 17; 18]. There are few reports on how to weaken the gas \"short circuit\" in the furnace. [PERSON] in Ref. [19] studied the burden segregation in a vertical cooling furnace of Meishan Steel using the discrete element method (DEM) and optimized the layout of the burden distribution pipe, changing it from a single discharge point to four discharge points, in order to alleviate the burden segregation distribution in the furnace and, thus, weaken the \"short-circuit\" airflow. In view of the primary segregation of the burden in a vertical cooling furnace of Meishan Steel, [PERSON] in Ref. [20] proposed adding a material distribution plate to the buffer bin to cause the sinter particles to form a pit in the center so as to alleviate the burden segregation distribution in the vertical cooling furnace and improve its air flow distribution. [PERSON] in Ref. [21] attempted to adjust the gas flow distribution in a vertical cooling furnace by adjusting the initial edge-center gas flow ratio. But on the whole, the effect of the above measures is limited. 2. A vertical cooling furnace is essentially a gas-solid moving packed bed. At present, there have been a large number of studies on the segregation of packed bed distribution [22; 23; 24] and the optimization of gas distribution in such a furnace [25; 26]. [PERSON] in Ref. [22] studied the influence of the cross-sectional shape of the rotating chute on the distribution of blast furnace burden. It was found that compared with semi-circular chutes, the thickness asymmetry of the material layer is smaller, the top of the material layer is closer to the center of the blast furnace, and the circumferential distribution of the material layer is more uniform when using rectangular chutes. [PERSON] in Ref. [23] used DEM to investigate the effects of the Y-tube diameter and mass flow rate on the circumferential mass segregation in a bell-less blast furnace. [PERSON] in Ref. [24] studied the filling positions, filling angles, and discharging outlet size on size segregation during PW hopper charging and discharging processes. [PERSON] in Ref.