China
Africa
Explore chapters and articles related to this topic
Metal Manufacturing Processes and Energy Systems
Published in Swapan Kumar Dutta, Jitendra Saxena, Binoy Krishna Choudhury, Energy Efficiency and Conservation in Metal Industries, 2023
Swapan Kumar Dutta, Binoy Krishna Choudhury
Direct reduced iron (DRI) is also known as sponge iron for its perforated look due to reduction of iron ore directly by either carbon or hydrogen (from natural gas or produced by electrolysis of water), thus justifying its name. DRI is also intermediate product, having no practical use other than to be processed further to produce steel. Because of vast variation of processing techniques on variety of ores, DRI could be of different physical and chemical properties as placed in Table 4.2.
Applications in Iron and Steel Making
Published in Nirupam Chakraborti, Data-Driven Evolutionary Modeling in Materials Technology, 2023
Directly reduced iron (DRI) in a rotary kiln is produced by the solid-state reduction of iron ore, using a reducing agent like CO or H2. The minute pores created by the removal of oxygen from the iron ore particles allow entry of CO into the particle and release of CO2 therefrom, through a counter-current diffusion process (Mohanty 2009), which provides the reduced iron oxides a spongy texture. Because of this, DRI is commonly referred to as sponge iron. Generally, it is used as a raw material for steel making in the electric arc furnace. The waste gases generated inside the kiln are of sufficient volume and calorific value and are utilized to generate steam for power generation.
Properties, Applications, and Prospects of Carbonaceous Biomass Post-processing Residues
Published in Vladimir Strezov, Hossain M. Anawar, Renewable Energy Systems from Biomass, 2018
Suraj Adebayo Opatokun, Vladimir Strezov, Hossain M. Anawar
The most recent emerging generation of smelting operations consists of direct reduction of iron ores with coal. Direct reduced ironmaking (DRI) processes have several advantages over the conventional blast furnace operations with low pollution effects and low capital-intensive operation, and they can provide successful smelting with low-grade thermal coal. The DRI process consists of carbo-thermic reduction of iron oxides directly with the volatiles liberated during coal devolatilization, carbon monoxide regenerated from coal char, as well as dissolved carbon in iron bath. The DRI technologies offer viable potential for substitution of coal with biomass as a carbon-bearing reductant material. Strezov (2006) found that iron ore can be successfully reduced to predominantly metallic iron using 30 wt% of biomass in a biomass-ore pellet. The shortcomings in potential development of biomass-based metal smelting technology is related to the low density of biomass, requiring larger volumes; hence it potentially can reduce the metal production rates. More realistically, charcoal can potentially provide substitution for coal in the direct reduced ironmaking technologies. Further research will be required to ensure the metallurgical operations maintain the desired levels of energy efficiency, productivity, and process quality.
Effect of rice husk volatiles in iron ore reduction and its kinetic study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Dipika Das, Amrit Anand, Shalini Gautam
A non-conventional route of iron making has rapidly developed in the last four decades, known as Direct Reduction Process (Dutta and Sah 2016). Direct reduced iron (DRI) can efficiently replace chemically consistent scraps for making steel (Punaykanti and Pani, 2016.). The DRI process is more economical as it reduces the cost of coke (Liu et al. 2004). Several researchers are using biomass in iron and steel making. According to John Mathieson (Mathieson et al. 2011), biomass cannot replace coke in a blast furnace because of its insufficient strength. Still, it can be used as a BF tuyere injectant in place of pulverized coal. In the year of 2013, Mašlejová A (Mašlejová 2013) concluded that, in the iron sintering process, it is possible to replace 10% of fine coke with biomass. A preliminary GHG (Green House Gas) footprint analysis revealed that using torrefied and pulverized biomass in the blast furnace would be the most environmentally favorable scenario for GHG emissions (Fick et al. 2014). Recently, there has been a growing interest in using biomass as a reductant as a source of energy for clean iron making, as investigated by (Guo et al. 2015) in the direct reduction of iron ore-biomass composite pellets with hydrogen gas.
Energy Optimization Studies for Integrated Steel Plant Employing Diverse Steel-Making Route: Models and Evolutionary Algorithms-Based Approach
Published in Mineral Processing and Extractive Metallurgy Review, 2021
Sagnik Chowdhury, Nirupam Chakraborti, Prodip Kumar Sen
The production of iron and steel is an energy-intensive process. In an integrated steel plant (ISP), finished steel is produced from iron-bearing raw materials using fuels which act as heat sources and also provide reducing agents. All ISPs consist of four major units: raw material handling and processing unit, ironmaking unit, steelmaking unit, and finishing mills. The worldwide average energy consumption for production of steel is about 20 GJ/t (World Steel Association 2019). The various forms in which final energy (final energy is defined as energy available at the production facility) is used for making iron and steel are fuels (which include solid fuels such as coke, pulverized coal, etc., liquid fuels such as fuel oil and gaseous fuels like natural gas), electricity, and heat. Coal provides the major proportion (64%) of the total energy requirement; electricity accounts for 20% followed by natural gas (11%); and the remaining 5% comes from oils, biofuels, etc. (International Energy Agency 2019). The availability of fossil fuels like coal and natural gas and their prices are among the major factors which impact the running of iron and steel industry. There is a need for improvement in energy efficiency to reduce fossil fuel consumption. Energy-intensive processes also have a direct environmental impact in the form of CO2 emission. Presently, blast furnace (BF)-basic oxygen furnace (BOF) route accounts for 70% of global steel production whereas 30% is produced by electric arc furnace (EAF) route (World Steel Association 2019). The shortcomings of BF-based hot metal (HM) production and advantages of alternative smelting reduction processes are available in the literature (Basu et al. 1993). The COREX (Siemens Vai) process is an alternative route for production of HM from iron ore pellets in which noncoking coal is used as the major fuel. The off-gas produced by this process is rich in CO and has a high calorific value (CV) (1,750 kcal/N m3). This off-gas can either be used as a fuel gas or it can be used as a reducing gas to produce direct reduction of iron (DRI) using a shaft furnace (Siemens Vai). The DRI production process generates an off-gas with some fuel value. As availability and cost of coking coal is becoming a serious issue, alternative routes of iron and steel production like COREX, shaft-based process for DRI and EAF in combination with BF-BOF route is becoming a matter of focus as is practiced by JSW Steel (India), Essar Steel (India), Bao Steel (China), etc. Mixed-route steel production provides flexibility in terms of steel production. If EAF is operating at lower capacity, the COREX HM can be diverted to BOF and the produced DRI can be stored or sold. If BOF vessels are not operating at full capacity, BF HM can be diverted to EAF and COREX off-gas can be diverted to compensate for the BOF gas for meeting downstream requirements. Energy optimization for plants producing steel using mixed route has not been studied in sufficient details. The present study is aimed at exploring the possibilities of energy efficiency improvement using mixed route in ISPs.