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The Steel Industry
Published in Alfred Linden Levinson, Energy and Materials in Three Sectors of the Economy, 2017
In our model we have focused on the steelmaking technologies. The process of producing finished steel from iron ore involves much more than just the steelmaking technology. Both the metallurgical coal and the iron ore undergo transformation before entering the production process. The coal is converted to coke. Coking is a destructive distillation process in which coal is subjected to high temperatures in order to reduce its volatile content. The residue, which is the coke, contains 85-90 per cent carbon with the remainder in ash, sulfur, phosphorous, and other substances. Coke is used primarily as a fuel and source of carbon in the blast furnace production of pig iron. There are several processes for the production of coke. They are the beehive oven process, byproduct process, continuous process, and formcoke process. The most commonly used method is the byproduct process because many types of low quality coal can be utilized by blending with other coals, and the gas coal chemicals released can be fully recovered. Higher yields and more uniform coke are also obtained. Currently 98 per cent of all coke production is produced in byproduct ovens.
Downstream Processing of Heavier Petroleum Fractions
Published in Prasenjit Mondal, Ajay K. Dalai, Sustainable Utilization of Natural Resources, 2017
Shubham Saroha, Prasenjit Mondal, Deepak Tandon
In the delayed coking process, the coke formation is obtained by providing a sufficient long residence time (delayed) in the coke drum. More lighters are obtained and coke is obtained as a by-product. Delayed coking consists of thermal cracking of heavy residue in the empty drum in which deposition of coke takes place. The product yield and quality depends on the type of feedstock processed. A typical delayed coking consists of a furnace to preheat the feed, a coking drum in which cracking and coke formation take place, and a downstream fractionator of the coke drum in which the fractionation of the vapor-phase products take place. A process flow diagram for delayed coking is shown in Figure 3.6. The feed is first preheated in the furnace in which the desired cooking temperature (around 490°C–510°C) is achieved and fed to the coking drums, which are maintained at a prefixed temperature and are normally installed in pairs where the cracking reaction takes place and the coke is deposited at the bottom of the drum. The pressure of the coke drum gradually builds up, and after attaining a required pressure (~3 kg/cm2), the coke drum overhead vapor is allowed to flow into the fractionating column in which it is separated into overhead streams containing wet gas, LPG, and naphtha as well as two-side gas oil streams. Recycled stream from the fractionating column combines with the fresh feed in the bottom of the column and is further preheated in the coke heater and flows into the coke drum. When the coke drum is filled, the heated streams from the coke heater are sent to the other drum.
Agglomerates in Iron-Making Processes
Published in Ram Pravesh Bhagat, Agglomeration of Iron Ores, 2019
The iron-making process is highly capital intensive; and hence, any improvement in productivity increases its profitability. The iron-making process through the blast furnace route uses coke, which is produced through the carbonization of coking coal. This commodity is costly and is limited in resources. Hence, much attention is paid toward the savings in coke rate. Hot metal/DRI is feedstock of the steel making and its quality is equally important to produce steel at cheaper cost. The hot metal/DRI should have minimum sulfur so that the desulfurization step, which is otherwise required, is avoided.
Effects of microscopic characteristics on post-reaction strength of coke
Published in International Journal of Coal Preparation and Utilization, 2022
Jun Zhang, Jiaxiong Lin, Rui Guo, Caixia Hou
Coke is a porous carbon material obtained from blending coking coals after high-temperature carbonization. This material plays an important role in the blast furnace process by serving as a source of heat, source of reducing agents, source of carbon for hot metal, and structural support that ensures permeability for gas and liquid. Therefore, the performance of coke determines the cost and benefit of the blast furnace process. In the late 19th century, Sir Lothian Bell recognized the importance of CO produced by the reaction between coke and CO2, and was the first to define equilibrium in the Fe-O-C system (Wakelin 1999). The concept of the coke solution loss reaction was proposed, based on this definition. This reaction provides reducing gas for the iron ore reduction process, but the structure of coke is damaged due to carbon loss during the reaction process. The coke thermal properties are usually determined through tests, proposed by Nippon Steel Corporation (NSC) at the end of 1960s, which yield the Coke Reactivity Index (CRI) and Coke Strength after Reaction (CSR) (The British carbonization research association (BCRA) 1980). However, the NSC test results differ significantly from the deterioration behavior of coke in a blast furnace (Barnaba 1993; Cheng 2001; Goleczka and Tucker 1985; Lundgren, Ökvist, and Björkman 2009). Therefore, some researchers have employed supplemental test methods, for example, where the strength after a certain (20% or 25%) carbon loss percentage is determined (Nomura et al. 2007; Wang et al. 2016).
A Scale-up Approach to Produce Highly Reactive Iron Ore Catalyzed Coke for Blast Furnace Operation
Published in Mineral Processing and Extractive Metallurgy Review, 2020
Hammad Siddiqi, V. K. Chandaliya, A. Suresh, P. S. Dash, B. C. Meikap
The fast-growing steel industries in the world are facing two prominent challenges, one is to reduce energy consumption, and another is to lower the greenhouse gas emissions. The major part of the energy consumed in steel manufacturing is in the form of metallurgical coke which is produced from coke ovens by feeding coking coals. Coke is the primary source of fuel in the blast furnace (BF). It also acts as a reducing agent by generating CO gas, support the burden and provide permeability in the bed. India has an acute shortage of coking coals, out of its total 240 billion tons (Bt) of reserves, only 18.3% are coking coal and rest are non-coking (Sah and Dutta 2010). This necessitates extensive research to use non-coking coals in coke making and thereby reducing the coke rate (Konishi, Ichikawa and Usui 2010). Also, due to the increasing demand of steel and environmental pollution problem associated with current technology, an alternate process techniques in coke and iron making is needed to reduce CO2 emissions (Benk, Talu and Coban 2008).
Metallurgical coke production with biomass additives. Part 1. A review of existing practices
Published in Canadian Metallurgical Quarterly, 2020
Andrii Koveria, Lina Kieush, Olena Svietkina, Yevhen Perkov
Utilisation of biomass in coke production allows reducing dependence on already depleting fossil fuel reserves. Coking coal is included in the European list of critical raw materials [7]. Additionally, the coking of coal blend with biomass additives makes it possible to reduce the cost of the produced biocoke due to the lower cost of biomass. Along with this, replacing coking coal with biomass allows reducing CO2 emissions due to the carbon neutrality of biomass because the carbon absorbed from the atmosphere by the plants is released to the atmosphere when the biomass undergoes thermal treatment. The emissions of harmful gases such as methane, SO2, and NOx are reduced due to the lower hydrocarbon content of the biomass and the very little amount of sulphur and nitrogen.