Waste Heat Recovery from Converter Gas by a Filled Bulb Regenerator: Heat Transfer Characteristics
Round 1
Reviewer 1 Report
In the paper entitled: ' Waste heat recovery from converter gas by filled bulb regenerator: Heat transfer characteristics', the authors claim to propose a new technology based on waste heat utilization using a filled balloon regenerator.
First, I think the editor didn't check the format of the article. For example, the bibliography has a different citation style, with underlined text and corrected formulas found on pages 5 through 8.
1- The authors claim to have established a mathematical model, which I believe has already been proposed. How new is the paper?
2- The article has a simple equation to solve. Thermal material properties were taken from other papers. Results are highly dependent on these properties. So please clearly explain your limitations and assumptions.
3- How did the author solve the equations?
4- Do you have experiments to validate your results or show trends?
Author Response
Response: Thank you for your kind suggestions. These errors have been revised in the revised manuscript. These suggestions are valuable for modification.
1- The authors claim to have established a mathematical model, which I believe has already been proposed. How new is the paper?
Response: In fact, the basic mathematical formula of unsteady heat transfer for gas-solid heat transfer does exist. Especially for sphere, the heat transfer model has been widely used. The research in this paper is revised on the basis of these mature models. Treatment of soot filtration process in the model is the key and innovation of this paper.
2- The article has a simple equation to solve. Thermal material properties were taken from other papers. Results are highly dependent on these properties. So please clearly explain your limitations and assumptions.
Response: Because the converter gas involved in the paper is easy to explode. Thus, it is difficult to directly verify the feasibility of the technology through experiments. It is representative data from the scene or literature, which can reflect the real situation to a certain extent. Thank you for your suggestion.
3- How did the author solve the equations?
Response:The numerical calculation process of heat transfer and flow in the regenerator can be divided into the following six steps:
(1) Parameter input and initialization;
(2) Mesh division and step calculation;
(3) From the beginning of the heating period, according to the initial temperature of the regenerator and the flue gas, the temperature and pressure of the regenerator in the heating period are calculated in turn with the time step method;
(4) According to the commutation conditions, the initial conditions of the temperature field in the cooling period are determined from the temperature field in the heating period, and the temperature and pressure in the cooling period regenerator are calculated in turn with the time step method;
(5) After the end of the heating period and the cooling period, judge whether the result reaches the iteration calculation number. If it meets the number, enter (6); otherwise, use the temperature field at the end of the cooling period as the initial temperature field of the heating period, enter (3);
(6) Calculate the average gas outlet temperature, temperature efficiency and thermal efficiency of the regenerator.
4- Do you have experiments to validate your results or show trends?
Response:The author and the research team carried out the mechanism experiment of minimum ignition energy as follow. However, due to safety factors, the experimental verification of the packed bed has not been carried out.[1] Qin Qin, Wang Kuming, Yu Qingbo, et al. Feasibility study on recovery of converter gas waste heat by honeycomb regenerator [J]. Journal of Northeast University (Natural Science Edition), 2018, 39 (11): 1608-1613.
Reviewer 2 Report
1.How does soot particle size affect dust removal efficiency?
2.How does initial soot concentration affect heat transfer and dust removal efficiency?
3.What is the effect of height of the regenerator on heat transfer and dust removal efficiency?
4.Can you give an example of a commutation cycle in a steel-making converter?
5.How does the temperature of gas and heat storage materials change during the heating and cooling periods in the regenerator?
6.How does the presence of soot in gas affect resistance loss in the regenerator?
7.Some format and language problems need to be revised.
Author Response
1.How does soot particle size affect dust removal efficiency?
Response:
The smaller the particle size of smoke and dust is, the harder it is to be captured by the ball, and it is easy to be carried away by the flue gas, thus reducing the dust removal efficiency. The larger the particle size of smoke and dust is, the easier it is to be caught by the ball and left in the equipment.
2.How does initial soot concentration affect heat transfer and dust removal efficiency?
Response: The higher the initial concentration of soot, the more dust particles will accumulate on the surface of the sphere in a heat transfer cycle, thus increasing the thermal resistance and reducing the heat transfer rate. At the same time, the accumulated dust will increase the resistance loss in the flow channel, thus reducing the dust removal efficiency, and some fine dust will be carried out.
3.What is the effect of height of the regenerator on heat transfer and dust removal efficiency?
Response: The height of the regenerator affects the gas heat transfer time, resistance and the movement distance of smoke and dust. The higher the height of the regenerator, the longer the heat transfer time of the gas, and the lower the outlet temperature. At the same time, the higher the height of the regenerator, the greater the resistance, and the higher the dust removal efficiency.
4.Can you give an example of a commutation cycle in a steel-making converter?
Response: The steelmaking process is intermittent, which is a common way of steelmaking process. However, the technology discussed in this article has not been implemented so far. This is a new technology and process designed by our team.
5.How does the temperature of gas and heat storage materials change during the heating and cooling periods in the regenerator?
Response: During the heating period of the regenerator, the gas temperature gradually decreases and the temperature of the thermal storage material gradually increases. During the cooling of the regenerator, the gas temperature gradually increases and the temperature of the thermal storage material gradually decreases.
6.How does the presence of soot in gas affect resistance loss in the regenerator?
Response: The smoke dust in the gas will gradually accumulate in the surface and gap of the sphere, thus gradually reducing the scouring sectional area of the flow process, thus increasing the resistance of the gas flow process.
7.Some format and language problems need to be revised.
Response: Thank you for your kind suggestions. These suggestions are all valuable. Some format and language problems have been improved. Thank you.
Round 2
Reviewer 1 Report
I recommend to accept the paper in this form.
