This is the source code of the simulation of the EAF, chosen as the key reactor model of our project.
It was done as part of Final Year Design Project of Chemical Engineering MEng degree in Imperial College London. This reactor modelling was awarded exceptional grade of A++ due to its exhaustiveness of simulation and novelty in reactor design. Reactor part of the report is on this repo and you can find it here.
Open the eaf.m file using MATLAB and press Run.
It will generate graphs describing mass and compositions of different zones at different time under predefined condition.
It was developed using MATLAB R2021a so it's recommended to run with at least this version of MATLAB.
The EAF plays crucial role in the steel production process as it converts the direct reduced iron (DRI) produced from the core chemical looping process along with steel scrap into the final steel product.
EAF was chosen over blast oxygen furnace as it outperforms from an environmental, process novelty and safety perspective, while only losing out in terms of overall economics and technological readiness.
This reactor model enables continuous operation as opposed to traditional batch operation, with its basis on an expired patent by the Danieli Corporation. The premise of design is the distinction between three separate ’melting zones’ within the furnace - a central melting zone flanked with two lateral shafts that are lower in elevation than the central melting zone. Each of the two lateral shafts are equipped with a bottom tapping port that enables continuous tapping of the liquid steel, as the furnace can be tilted 15 degrees to either side to discharge the product.
This model is time-variant, consisting of a combination of first-order differential equations and other algebraic relationships, solved using the fixed-step forward Euler method with a time interval of 10−3 s. In addition, discontinuities were modelled such that no instability issues occurred. The EAF is divided into different homogeneous zones where the components in each zone have identical chemical, thermal and physical properties. This assumption makes it simpler to model the relationships between different phases (solid, liquid and gas) present in the system.
The EAF model consists of all three mechanisms of heat transfer: conduction, convection and radiation.
- Conduction occurs between zones that are in direct contact with one another.
- Convection occurs between the gas zone and the surrounding zones.
- Radiation occurs between zones depending on the value of the view factor.
In order to calculate the view factors, the surfaces were approximated as basic individual geometric shapes or a combination of these, with different spatial orientations. This is because the view factors change as a result of the geometric ratios changing during the operation of the furnace. Since the EAF is operated continuously for this process, the view factors are assumed to only consider phase 3 (arc exposure to liquid metal) and phase 4 (slag foaming).
Mass transfer happens through the following processes:
- Mass addition
- Mass Changes from Chemical Reactions
- Melting
Mass addition to each component in each zone either through direct reduced iron, scrap steel addition, ferromanganese addition, slag forming material addition, O2 lancing, O2 post-combustion and C injection is factored in. The changes in mass for each component within their respective zones occur due to the reactions taking place in the EAF. Using the heat transfer established above, the mass transfer relationships can be constructed.
The oxidation and reduction reactions that are considered are based upon the significance of their impact on the overall energy balance of the EAF. The model assumes that all reactions take place in the liquid metal and liquid slag zones, except the CO post-combustion. The chosen reactions are following:
Refer to Sensitivity/README.md
Refer to Optimization/README.md
In terms of future recommendations, we believe that extensive research should be conducted on improving the nature of the view factor analysis included in the model. Due to the continuous mode of operation, modelling view factor behaviour such that the central melting zone and the lateral shafts are considered to be separate zones would greatly improve the reliability of results, as the radiative heat transfer phenomena would be more accurately represented.
Accounting for a continuous solid metal feed with semi-continuous tapping cycles would also be a means of expanding upon the phases of operation outlined in literature. To further improve tapping times and furnace efficiency, we can also look to adapt the findings from the patent further by testing out the viability of increasing the number of lateral shafts present within the reactor to three or four secondary zones such that tapping can occur more swiftly.
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Special thanks to teammates of Colosseum Steelworks:
- Aiman Syahirah Ahmad Dzulfakhar
- Theeranai (Bek) Charaschanya
- Athanasios (Thanos) Charos
- Naomi Duru
- Fatima Elzahra Khan
- En You Sim
- Alessandro Tonus
- Pierre Walker
- Richard Woolley
Also, thank you very much to supervisors who helped us throughout the process
- 2023-11-25: Added proper READMEs and remove unnecessary files from the repo.