The Perspective of Using the System Ethanol-Ethyl Acetate in a Liquid Organic Hydrogen Carrier (LOHC) Cycle
, Riccardo Tesser 2,3, Sara Fulignati 3,4 and Anna Maria Raspolli Galletti 3,4
Round 1
Reviewer 1 Report
The paper is a review on the use of ethanol as hydrogen storage. The review itself describe the dehydrogenation/hydrogenation of ethanol as LOHC system, although there is still not consensus on the use of this system as LOHC. only one paper called it as LOHC. A more in-depth description of the disadvantages of the system is required to avoid giving misleading messages.
for instance, there are several possible biproducts that make the system not really stable as LOHC. having at best 94% selectivity means that in each cycle we loose a part of the ethanol, which should be then restored.
One of the byproducts, at the temperature of dehydrogenation, could be CO which makes the H2 produced unsuitable for use in fuel cells for instance.
I suggest the authors to explore more the byproducts.
More details on the use of membranes and membrane reactors can be given.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The review of the production of ethylacetate and hydrogen as by product from ethanol present important aspects of the process. The use of ethanol in a Liquid Organic Hydrogen Carrier (LOHC) process is very important in the future for the storage of hydrogen. The paper is very interesting and the discussions very important for the implementation of a hydrogen storage process.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The review presents the state-of-the-art concerning dehydrogenation of ethanol and hydrogenation of ethyl acetate and the possible use of this pair as a LOHC system. The work certainly deserves publication but some minor remarks should be kept into account for greater consistency. Please make the notations uniform: some temperatures are in °C, other in K, some pressures are in atm, other in bar, other in MPa !... and use preferably SI units (energies are in kcal/mol in your text).
Enthalpies should be given per mol of hydrogen for a better comparison of the systems and not per mol of LOHC (l. 618-630).
Gibbs free energies are not commented. Is it worth mentioning them? If yes, please check the values.
Please use a space or a midpoint between units ("g h" and not "gh").
Typos and sentences to be rephrased:
- l.39: comma before point
- l.232: heatin (space missing)
- l.255 interpreted all the kinetic runs (for missing)
- l.319 was quite low not needing to be -> reformulate
- l.326 if you want to -> reformulate
- l.342 m3 (exponent)
- l.481 Cu/Zn resulted 1:1 -> reformulate
- l.494 an LHSV (a)
- l.565 Mewavala (Mevawala)
- l.597, 613, please write methylcyclohexane in one word
- l.633 Saying that one mole of H2 must be used to sustain the dehydrogenation reaction is to affirmative. Other options exist to bring the required heat. Please reformulate.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The paper has been improved and the answers to the comments are convincing. the paper could be accepted now
