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Use of conventional carbonaceous fuels in the pig iron production
Published in Jaroslav Legemza, Mária Fröhlichová, Róbert Findorák, Biomass and Carbon Fuels in Metallurgy, 2019
Jaroslav Legemza, Mária Fröhlichová, Róbert Findorák
The reduction of energy intensity of the pig iron production is a consequence of changes in the fuel base. This means using an increasing share of alternative fuels. Nowadays, coal is not used only for the production of blast furnace coke, but it is also used directly for blowing into a blast furnace in a powdered or granulated form by tuyeres. The new alternative processes for the production of pig iron (e.g. HISMELT) use coal for a similar purpose. The substitution of blast furnace (metallurgical) coke, which is the most expensive component of the charge, by blowing pulverised coal (up to 220 kg.t−1 p.i.) runs without a fundamental change of the blast furnace process technology. The theoretical maximum of this intensification technology is the value of 270 kg.t−1 p.i. This limit is imposed by carrying capacity of blast furnace coke and the thermochemical conditions in the blast furnace. In the case of pulverised coal injection, it is important to ensure improved coke strength after reaction with carbon dioxide (CSR) [63].
Ferrous Metals Waste Production and Recycling
Published in Sehliselo Ndlovu, Geoffrey S. Simate, Elias Matinde, Waste Production and Utilization in the Metal Extraction Industry, 2017
Sehliselo Ndlovu, Geoffrey S. Simate, Elias Matinde
The quality, cost and availability of metallurgical coal present a major raw material constraint in the blast furnace process. Although the use of auxiliary fuels has gained traction as alternatives in reducing the coke rate per 1 ton hot metal, there is no satisfactory reductant material that can fully or partially replace the coke in the blast furnace (Biswas, 1981; Diez et al., 2002). Metallurgical coking coals must produce, when coked, the specified mechano–chemical stability properties, such as those measured by the coke strength after reaction in CO2 (CSR), to support the blast furnace charge and enhance aerodynamic characteristics. The CSR parameter measures the potential of coke to break down into smaller sizes in the high temperature and high CO/CO2 gas ratio environment that exists in the lower parts of the blast furnace (Diez et al., 2002; ASTM D5341, n.d.). Coking coals which, when coked, achieve a high CSR value are considered premium and are highly regarded in the blast furnace process. As a result, good quality coking coals are required to produce high grade metallurgical coke (Diez et al., 2002). Nevertheless, only certain types of coals, ranked as coking or bituminous coals, possess the right thermos-plasticity and physicochemical properties suitable for coke making, with the majority of coals being applicable only as coal blends to improve blast furnace productivity (Ball et al., 1973; Biswas, 1981; Diez et al., 2002). Diez et al. (2002) proposed that proper coal selection and blend composition based on coal rank, rheological properties, petrology and ash chemistry represent one of the major factors used to control the mechanical and chemical coke properties. Because metallurgical coke is such an indispensable raw material and major cost driver in the blast furnace iron making, securing long-term supplies of premium grade coking coals has always been a top priority for most blast furnace producers globally.
Evaluation of Indian non-coking and semi-coking coals for metallurgical application
Published in International Journal of Coal Preparation and Utilization, 2023
Rashmi Singh, Debjani Nag, Satyaki Bhattacharya, Pratik Swarup Dash, Partha Pratim Banerjee
The quality of coke is determined by coke reactivity index (CRI) and coke strength after reaction (CSR) as per International standard (ISO 18894, 2006) [27]. CSR or Coke Strength after Reaction with CO2 is a coke quality tool used to express the behavior of coke at high temperatures. The CSR of coke shows its ability to withstand high temperatures in CO/CO2 environment without much change in its physical state. CSR is measured after the coke is reacted with CO2 at 1100°C for 2 hours and rotating the cooled coke in an I-drum for 30 minutes at a speed of 20 rpm. Coke Reactivity Index or CRI indicates the rate at which the coke reacts with the oxidizing gases like CO, CO2 etc. CRI is measured in the same experimental setup as that used for CSR. It is calculated as the percentage loss in weight of coke during the reaction with CO2 at 1100°C for 2 hours.
Post reactive strength and reactivity of metallurgical coke: infrared gas analyzer
Published in International Journal of Coal Preparation and Utilization, 2022
Deepak Kumar, V. K. Saxena, H. P. Tiwari, V. K. Tiwary
The coke is one of the critical raw materials in the blast furnace ironmaking process, which forms a packed bed in the blast furnace burden and withstands the flow passes of hot metal and slag toward the hearth. It also maintains the high temperature, reducing gas toward the upper part of the reducing and smelting zone. The coke strength after reaction (CSR) and coke M40 are the main aspects for assessing the coke quality for the blast furnace’s smooth operation. Therefore, the effort is being made worldwide to improve the blast furnaces operational efficiency with the lower coke rate. However, all these specified test properties are only the test results under limited conditions, and the breakage phenomenon of coke particles may vary in the blast furnace.