An Experimental Study on Performance and Structural Improvements of a Novel Elutriator
James Zhou
Round 1
Reviewer 1 Report
Authors of this manuscript (MS) reported improved separation efficiency obtained from BIE after modifying the design of an old device UGS. The experimental comparison between the BIE and UGS clearly showed that the dust-removing efficiency of the BIE had been dramatically enhanced. However, this reviewer would like to make the following suggestions for further improvement of presentation and clarification of this MS.
- For the experimental side, there was no comparison data of LDPE resin (large particles) recovery or loss in this MS but in the Conclusion section, authors claimed that the escape of large particles was solved using the BIE. This claim needs to be validated. In addition, the details of the experimental work were not sufficient. For instance, was there any air leakage during the feeding and resin discharging? What was the critical moisture level in the feed and airflow? Was the temperature control required during the experiments?
- For the theoretical front, in the MS, there was no specific equation of shear force (Orson’s modified formula), which was crucial for removing dust on the surface of the resin particles. In theory, the shear force derives from air viscosity x velocity gradient (du/dx) around the resins. It was not clear how the shear force played a major role in the removal of dust from the surfaces of the resin particles. Instead, the effects of collision, falling, bouncing of particles in a turbulent environment contributed significantly on the ejection of dust from the resin particles. The mechanism of dust removal in BIE should be unambiguously elucidated.
- The presentation of this MS was poor and need to be improved. For example,
- Past tenses should be used in the Abstract and Results and Discussion sections if things have happened. It seems to me that the authors could not distinguish the difference of past experiments and present statement.
- It should be Fig. 5(b) on the line of 164.
- It should be experimentally rather than experimental on the line of 181.
- On the line of 207, “The primary air inlet is aimed to ….”, remove “inlet”.
- The title “3. Experimental setup” was repeated on the line of 122 “3.2. Experimental setup”. To avoid such repetition, both titles can be changed to 3. Experimental and 3.2. Setup.
Besides the errors being mentioned above, authors should carefully check all spellings and grammars of the whole MS again to ensure the mistakes are kept as little as possible.
Author Response
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Reviewer 2 Report
General remarks:
- In Figure 3A, the authors present the distribution of the particle size in the sample as a frequency function. I suggest drawing a particle cumulative distribution curve from which it is possible to deduce exactly what the particle contents are in each class size. It will be more readable and will allow to read the content of fine particles.
- Fig. 10 shows pictures of particle samples before and after separation in the devices. For comparison, I suggest to make and show the particle size distribution of these samples. Then it will be possible to unequivocally assess the effectiveness of the separation. The imperfection index is used to assess the effects of separation and the accuracy of the device operation in the processing of materials. If the particle size distribution of the samples is known, the separation efficiency in the devices can be calculated and compared.
Author Response
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Reviewer 3 Report
In this paper, the authors proposed the improvements for the upstream gravitational separator (UGS), which is applied to separate the low density polyethylene (LDPE) resin particles and fines (powder, fiber, etc.). To improve performances of the UGS, a new bounced inertia elutriator (BIE) was developed. An experimental study was performed to access the efficiency of the BIE in comparison with the UGS. The paper is sound and interesting. For this reasons, after having clarified the following issues, I recommend a publication in Processes:
- In Eq. (1), it is not clear for me how we can compute different parameters. How can you determine the initial quantity of the dust?
- Always in Eq.(1), what is ‘i’ signify in ‘f_i’ and c_i’?
- For almost all the curves, different results points are fitted using the tendency curves by knowing that we don’t know exactly what the system behavior is between these points. Hence, you should relate the result points only by a straight line.
- In all the results presented for the BIE, the separation efficiency is very high (more than 96%) and the different studied parameters have an insignificant effect on the efficiency. This is well-shown in Fig. 9. It is better that the separation efficiencies of the UGS and the BIE are shown quantitively at the beginning of the paper to help readers appreciate more the new design.
- At the beginning of Sect. 4.3, please explain what ‘dust feeding speed' is. Isn’t it ‘feeding speed’?
Author Response
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Round 2
Reviewer 1 Report
I have reviewed the latest MS and found that the clarity of the MS has been improved greatly. However, to maintain the high quality of this journal, I would suggest the authors to look at the MS once again, in particular, about tenses being used in the whole MS. In general, you need to use Past Tense if the activities have already happened (e.g. 2. Design and 3. Experimental sections).
As an example, I have slightly twisted the Title and Abstract for your consideration.
An experimental study on performance and structural improvements of a novel elutriator
During the transportation and packaging of low density polyethylene (LDPE) granular materials, fine dusts such as floccules, powder and fibre will be produced, which pollute the environment, affect product quality and generate fire hazards. In this work, the separation performance of fine dust and optimal operating conditions of an improved elutriator were investigated experimentally. Experiments were carried out to investigate the effects of air speed, feeding speed and grid layout on the removal efficiency of fine particles. Experimental data showed that the separation efficiency of the novel elutriator ranged from 96% to 98.50%, which was more stable and average 51.44% higher than that of the original elutriator. By setting internals and improving the structure, the gas flow field in the equipment was regulated, the particle dispersion was intensified, and the static electricity was eliminated, which significantly improved the separation efficiency of fine dust.
This is a good article technically. This reviewer believes it may be published.
Author Response
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