Integration of Open Slag Bath Furnace with Direct Reduction Reactors for New-Generation Steelmaking
, Angelo Perrone 1, Alessio Silvello 2, Paolo Stagnoli 3 and Pablo Duarte 4Round 1
Reviewer 1 Report
This work presents an innovative steel processing route developed by employing hydrogen direct reduced pellets and open slag bath furnace in order to clean for decarbonization of the steel industry. The kinetic, chemical and thermodynamic issues are detailed with particular attention to the slag conditions, and by the economic evaluation compared to traditional routes, the proposed solution is also supported, which are useful for controlling and optimizing the new route for steel production. The publication of this manuscript is recommended.
However, the paper may be further improved if the authors can address the following issues:
- When you use abbreviations, you should be explained them above, and please attention to the abbreviations in your paper.
- add (OSBFs) after “open slag bath furnaces” in Line 51 before you use OSBFs in Line 53.
- add (submerged arc furnaces) in Line 206 before you use SAF in Line 206.
- Please explain the meaning of the word OSBD in Line 288.
- As described in your paper, the self-regulating nature of SAFs is largely absent from the OSBFs, and so the OSBFs rely more strongly on process control. It is necessary that a mass and energy balance should be built up for the OSBFs, and this can be used to develop operator guidance tables. The tables show the required changes in feed rate and power, to accommodate changes in prereduction, and to correct overcharged and undercharged furnace conditions, which can be found in References 12, how does your existing model differ from the model in the reference? Where is your innovation?
- If possible, the authors are advised to merge the three graphs in Figure 6, so that the influence of each factor can be more clearly identified.
- Please revise the Reference format and delete redundant serial numbers. Such as [1], [2], [3]…….
Author Response
- When you use abbreviations, you should be explained them above, and please attention to the abbreviations in your paper.
- add (OSBFs) after “open slag bath furnaces” in Line 51 before you use OSBFs in Line 53.
- add (submerged arc furnaces) in Line 206 before you use SAF in Line 206.
Done
- Please explain the meaning of the word OSBD in Line 288.
It was an error, we corrected with OSBF
- As described in your paper, the self-regulating nature of SAFs is largely absent from the OSBFs, and so the OSBFs rely more strongly on process control. It is necessary that a mass and energy balance should be built up for the OSBFs, and this can be used to develop operator guidance tables. The tables show the required changes in feed rate and power, to accommodate changes in prereduction, and to correct overcharged and undercharged furnace conditions, which can be found in References 12, how does your existing model differ from the model in the reference? Where is your innovation?
Our results differ from [12] because of the employed raw materials and of the reduction performed in the DRI reactor.
- If possible, the authors are advised to merge the three graphs in Figure 6, so that the influence of each factor can be more clearly identified.
Sorri, but we do not understand. Figure 6 is just a picture, it is not a graph.
- Please revise the Reference format and delete redundant serial numbers. Such as [1], [2], [3]…….
Done
Reviewer 2 Report
Dear authors,
the submitted manuscript proposes a new route for steelmaking by integrating direct reducing process of iron ore by hydrogen with open slag bath furnace (OSBF) for reducing CO2 emission and energy consumption. The introduction of OSBF could be recognized as a unique and interesting method to prepare Fe-C alloy from direct reduced iron (DRI) for steel production. Several optional comments are proposed below, which could be used for improving the manuscript:
(1) In the Introduction, the purpose for introducing the OSBF is not clear. Please add several statements to explain the meaning of the OSBF in the proposed steelmaking procedure.
(2) Many kinds of abbreviated expression (e.g. DRI as direct reduced iron) are represented in the manuscript, which make the readers complicated. The definition of each abbreviated expression should be summarized as a Table in the manuscript.
(3) In the Introduction, the phrase "that needs to be captured and stored" comes doubly, the latter of which could be removed.
(4) More details should be stated in the experimental procedure. Some of the statements shown in the section of Results and Discussion could be moved to the experimental procedure to explain details for OSBF operation.
(5) In Fig. 3 or 4, the materials of the electrodes should be represented. If carbon is used as the electrode material, then it may also affect the CO2 emission when the OSBF is operated.
(6) In the analysis shown in Fig. 12, how did the CO2 content in the off gas stream are taken account? Considering the Boudouard equilibrium, some amount of CO2 should exist equilibrated with CO and O2 in the gas stream.
(7) Several more references related to hydrogen steelmaking could be added, such as: A. R. Costa, D. Wagner, F. Patisson, Journal of Cleaner Production 46 (2013) 27-35; H. Hamadeh, O. Mirgaux, F. Patisson, Materials 2018, 11, 1865 (doi:10.3390/ma11101865); F. Patisson and O. Mirgaux, Metals 2020, 10, 922 (doi:10.3390/met10070922).
Author Response
(1) In the Introduction, the purpose for introducing the OSBF is not clear. Please add several statements to explain the meaning of the OSBF in the proposed steelmaking procedure.
Additional sentences were provided to support our study (please find highligthed in green).
(2) Many kinds of abbreviated expression (e.g. DRI as direct reduced iron) are represented in the manuscript, which make the readers complicated. The definition of each abbreviated expression should be summarized as a Table in the manuscript.
An abbreviations sections was provided after the heywords.
(3) In the Introduction, the phrase "that needs to be captured and stored" comes doubly, the latter of which could be removed.
Done
(4) More details should be stated in the experimental procedure. Some of the statements shown in the section of Results and Discussion could be moved to the experimental procedure to explain details for OSBF operation.
Some paragraphs were moved to the experimental procedure section as required
(5) In Fig. 3 or 4, the materials of the electrodes should be represented. If carbon is used as the electrode material, then it may also affect the CO2 emission when the OSBF is operated.
Figure 4 was modified accordingly
(6) In the analysis shown in Fig. 12, how did the CO2 content in the off gas stream are taken account? Considering the Boudouard equilibrium, some amount of CO2 should exist equilibrated with CO and O2 in the gas stream.
They were measured per each plant configuration
(7) Several more references related to hydrogen steelmaking could be added, such as: A. R. Costa, D. Wagner, F. Patisson, Journal of Cleaner Production 46 (2013) 27-35; H. Hamadeh, O. Mirgaux, F. Patisson, Materials 2018, 11, 1865 (doi:10.3390/ma11101865); F. Patisson and O. Mirgaux, Metals 2020, 10, 922 (doi:10.3390/met10070922).
The additional references were provided
Reviewer 3 Report
The conclusion and discussion are not complete, concerning economics (no comparison with HDRP), with statated objective: " we present an innovative soluction for steelmaking production based on hydrogen assisted direct reduced iron and subsequent melting and refining in open slag bath furnace"
It is not clear in the table 2, H2 energy for HDRI, if it is computed the necessary energy for H2 production by electrolisis. Consequently at conclusion "the employment of hydrogen reduced the energy consumption with respect to the natural gas direct reduction route"
None of the figures and tables have references! Are authors of all of them?
Please complete the reference (1): Publisher of the book and total pages
Author Response
It is not clear in the table 2, H2 energy for HDRI, if it is computed the necessary energy for H2 production by electrolisis. Consequently at conclusion "the employment of hydrogen reduced the energy consumption with respect to the natural gas direct reduction route"
In table 2 they are both indicated the hydrogen consumption as well as the total energy provided to the system.
None of the figures and tables have references! Are authors of all of them?
We are obviously authors of all the pictures. (The plant figures were directly provided by TENOVA engineers, co-authors of the present paper).
Please complete the reference (1): Publisher of the book and total pages
The additional informations were provided in the reference
