The Significance of the Sorption Isotherm on the Simulated Performance of Grain Driers

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript presents a detailed analysis of the impact of sorption isotherms on the drying performance of grain driers, with a focus on canola as the exemplar commodity. The study is well-structured and provides valuable insights into the thermodynamic and kinetic aspects of grain drying. The author has done a commendable job in deriving algebraic expressions to quantify the relationship between isotherm equations and drying rates. However, there are several areas where the manuscript could be improved to enhance its clarity, rigor, and overall contribution to the field.

Major Comments:

Introduction and Background:

The introduction provides a good overview of the importance of sorption isotherms in grain drying. However, it would benefit from a more detailed discussion of the current challenges and gaps in the literature, particularly regarding the inconsistencies in published sorption isotherm data. The author should also elaborate on the practical implications of these inconsistencies for the design and operation of grain driers.

 

Mathematical Formulation:

The mathematical analysis is thorough, but the presentation could be improved for better readability. Specifically, the derivation of key equations should be more clearly explained, with intermediate steps provided to help readers follow the logic. Additionally, the assumptions made in the derivation should be explicitly stated and justified.

Results and Discussion:

The results section is well-presented, but the discussion could be expanded to provide deeper insights into the observed phenomena. For example, the author should discuss why the empirical expression leads to lower drying rates compared to the Clausius-Clapeyron approach. Additionally, the implications of the findings for the design and optimization of grain driers should be more explicitly addressed.

Conclusion:

The conclusion is concise but could be expanded to summarize the key findings more effectively. The author should also discuss the broader implications of the study for the field of grain drying and suggest directions for future research.

 

Minor Comments:

Language and Clarity:

The manuscript is generally well-written, but there are a few instances where the language could be clarified. For example, in the introduction, the phrase "Prima facie it is anticipated the heat of adsorption will augment the speed of temperature waves through beds of drying canola" could be rephrased for better clarity.

 

Author Response

See attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The study is an interesting one and presents useful information highlighting the importance of reliable sorption isotherms and refined/ revised models for designing energy-efficient and effective grain drying systems. I commend the author’s effort and critical thinking to address the anomalies in widely used sorption isotherms. In my opinion, this study outcome will be a useful reference for future drying studies and better drying process control. Based on my knowledge and understanding of this study's results, I have a few comments that may assist in improving the quality and clarity of this article.  

Comments:

• Considering the rationale of this study, it is interesting to know how can discrepancies in widely cited sorption isotherms (modified Chung-Pfost and Halsey isotherms), impact the design and optimization of real-world grain drying systems?
• Line 128: How are dispersive effects modeled or observed in practical systems when accounting for spreads of moisture, temperature, and humidity on the drying and temperature fronts?
• Line 156-157: Can you elaborate on the mechanism of condensation in state P and how it relates to the grain's adsorption process?
• Line 283, 306, 307: values could be presented in two decimals. It does not benefit by presenting values up to 6^th Check the entire article for consistency.
• In my opinion presenting the relative humidity values in percentage would benefit the readers and avoid confusion, particularly in X-axis of figure 4 and its related discussion. Please mention the unit for RH in figure 4 and 5.
• 371: Why does the modified Chung-Pfost isotherm yield negative moisture content values at relative humidity below 0.025, and is this issue specific to the isotherm or the applied conditions?
• 405: it may benefit readers if you explain how Cenkowski et al. used equation differs from the Clausius-Clapeyron equation in predicting ℎ𝑠ℎ𝑣⁄? What was the specific benefit of changing the equation other than the moisture function?
• Was there any effort or is there a need for validation of the study’s outcomes?
• What are the specific implications of the divergent results between empirical equations for the heat of wetting and the Clausius-Clapeyron equation, particularly in predicting the energy requirements for drying canola?
• Considering the counterintuitive study’s finding that the heat of wetting does not augment the rate of heating, how can drying system designs be adjusted to account for such complex thermodynamic behaviors?
• What are the author's recommendations for future researchers, improvements in the modeling or modeling approaches, and data collection for sorption isotherms in grain drying systems?

Author Response

See attachment

Author Response File: Author Response.pdf