scholarly journals Numerical Analysis of Radiative Heat Transfer and Direct Reduction of Three-Dimensional Multilayer Ellipsoidal Carbon-Containing Pellet Unit in the Rotary Hearth Furnace

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 994
Author(s):  
Nan Li ◽  
Feng Wang
Keyword(s):  
Heat Transfer ◽  
Removal Rate ◽  
Direct Reduction ◽  
Reduction Process ◽  
View Factor ◽  
Radiant Heat Transfer ◽  
Rotary Hearth Furnace ◽  
Reduction Degree ◽  
Hearth Furnace ◽  
Direct Reduction Process

It is very important for a multilayer pellet bed to have a proper description of the radiant heat transfer and direct reduction process in the rotary hearth furnace. Ellipsoidal pellets may also be used in industrial production. The research on this ellipsoidal pellet bed will provide comprehensive data support for the production process. Besides, the view factor is one of the important factors affecting the heat transfer of the multilayer pellet bed. It is of great significance to study its value and distribution. In this study, the effects of the gas field and the bottom of the furnace on the direct reduction of multilayer ellipsoidal pellets were considered. The local environmental viewing angle coefficient in the model was obtained through the mechanism calculation method, which is more accurate than the calculation through the radiation exchange network. Furthermore, the porosity variation in the pellet during the direct reduction process was also considered. According to the calculation, it was found that the higher initial temperature at the furnace bottom is beneficial to increase the degree of metallization (DOM) and zinc removal rate (ZRR) for all pellets, and is more advantageous to the lower pellets in the material bed. Nevertheless, the reduction degree of the lower pellets is still smaller than that of the upper pellets. The results also show that increasing the offset ξ has a greater effect on increasing the ambient view factor and each position reduction degree in the ellipsoidal pellets layer. Results can be applied for the optimization of pellets distribution in a rotary hearth furnace.

Development Prospect of Rotary Hearth Furnace Process in China

2013 ◽  
Vol 746 ◽  
pp. 533-538 ◽  
Author(s):  
Ying Yi Zhang ◽  
Yuan Hong Qi ◽  
Zong Shu Zou ◽  
Yun Gang Li
Keyword(s):  
Resource Allocation ◽  
Iron Ore ◽  
Direct Reduction ◽  
Reduction Process ◽  
Economic Security ◽  
Practical Significance ◽  
Low Grade ◽  
Rotary Hearth Furnace ◽  
Hearth Furnace ◽  
Direct Reduction Process

Summarized the development situation of rotary hearth furnace (RHF) direct reduction technology, ore resource allocation situation and direct reduction iron demand. The survey results show that: China's iron ore resource allocation heavily rely on imported iron ore, gas-based direct reduction process (MIDREX, HYL-III, FINMET) is not likely to be the mainly direct reduced iron (DRI) process in China. However, non coking coal resources is very rich in China, research and development of coal-based direct reduction process (such as FASTMET and ITMK3 process) has important practical significance, it can strengthen the comprehensive utilization on low grade iron ore, associated mineral resources and iron & steel plant dust and sludge. It has great significance to alleviate steel scrap demand and stable development of the iron and steel industry and protect the national economic security in China.

Formation Mechanism of Soot in Zinc-Bearing Dusts Direct Reduction Process

2010 ◽  
Vol 156-157 ◽  
pp. 817-823 ◽  
Author(s):  
Xue Feng She ◽  
Qing Guo Xue ◽  
Hui Xian Yang ◽  
Yin Gui Ding
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Direct Reduction ◽  
Reduction Process ◽  
Rotary Hearth Furnace ◽  
X Ray Diffraction ◽  
Hearth Furnace ◽  
Direct Reduction Process ◽  
X Ray ◽  
Scanning Electron

The high-temperature tube furnace was applied to simulate the rotary hearth furnace (RHF) for the direct reduction of the zinc-bearing dusts from steel plants. The soot generated in the direct reduction process was studied by chromatography, X-ray diffraction (XRD), .and scanning electron microscopy (SEM) etc. The results suggested that the main phases of the soot were ZnO, KCl, NaCl and Zn5(OH)8Cl2H2O. Furthermore, the contents of Zn reach to 64.2% which could be used as secondary resources for zinc making. It is concluded that KCl and NaCl resulted from the volatilization from the briquettes at the experimental temperature of 1573K, while the ZnO were produced by the oxidation of the Zn vapor reduced from briquettes.

Study on Direct Reduction Process of Cylindrical Briquetting Hematite

2020 ◽  
Vol 988 ◽  
pp. 36-41
Author(s):  
Andinnie Juniarsih ◽  
Anistasia Milandia ◽  
Actur Saktianto ◽  
Suryana
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Iron Ore ◽  
Raw Materials ◽  
Direct Reduction ◽  
Reduction Process ◽  
Iron And Steel ◽  
Direct Reduction Process ◽  
Rate Study

There are two types of iron resources such as primary iron ore and iron sand. In general, primary iron ores use as raw materials in iron and steel making and can reduce directly. In Direct reduction process, Fe2O3 (hematite) is converted to metallic iron by the removal of oxygen. This work presents a heat transfer rate study for direct reduction process of iron ore cylindrical briquette. An investigation has been carried out of different reduction parameter such as different sizes cylindrical geometry over temperatures ranging from 700°C to 1100°C for reaction time from 10 minutes to 1 hour. The result was indicated that the value of the heat transfer rate decreases in the core and outer parts of the cylinder briquettes.

Separation of aluminium and preparation of powdered DRI from lateritic iron ore based on direct reduction process

2016 ◽  
Vol 55 (3) ◽  
pp. 345-355 ◽  
Author(s):  
T. Jiang ◽  
L. Yang ◽  
G. Li ◽  
J. Luo ◽  
J. Zeng ◽  
...  
Keyword(s):  
Iron Ore ◽  
Direct Reduction ◽  
Reduction Process ◽  
Direct Reduction Process

Numerical analysis of the carbon containing pellets direct reduction process

2021 ◽  
Vol 118 (2) ◽  
pp. 209
Author(s):  
Nan Li ◽  
Feng Wang ◽  
Wei Zhang
Keyword(s):  
Direct Reduction ◽  
Reduction Process ◽  
Operating Conditions ◽  
Utilization Efficiency ◽  
Heat Absorption ◽  
Furnace Temperature ◽  
Chemical Reaction Kinetics ◽  
Direct Reduction Process ◽  
Pellet Surface ◽  
Composite Pellets

In view of the carbon-containing composite pellets direct reduction process in rotary hearth furnace, a mathematical model coupling heterogeneous chemical reaction kinetics, heat and mass transfer of this process was established. The effects of furnace temperature (from 1273.15 K to 1673.15 K) and pellet radius (from 6 mm to 16 mm) on the direct reduction of carbon-containing composite pellets were studied by adopting computational fluid dynamics software. The pellet temperature and composition changes under different operating conditions were analyzed. CO and CO2 fluxes, heat fluxes on the pellet surface were especially studied. Total heat absorption by the pellet, CO and CO2 overflow from the pellet surface together with pellet degree of metallization (DOM) and zinc removal rate (ZRR) were calculated. Results show that with the increasing of furnace temperature or the decreasing of the pellet radius, the temperature difference between pellet surface and its center and the final DOM, ZRR increased. The larger the pellet radius, the smaller the heat absorption, also the smaller CO and CO2 overflow. But heat absorption and CO overflow per unit volume are higher. There is an optimal pellet radius with high CO utilization efficiency. Pellet porosity decreases at first and then increases with reducing time. It is also found that effective thermal conductivity is a major factor limiting the pellets temperature increasing. The reduction sequence of the pellets is Fe2O3→Fe3O4→FeO→Fe.

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