Advancements in Optimization and Control Techniques for Intensifying Processes

Round 1

Reviewer 1 Report

The authors present a review of works related to several components of the design of intensified processes. The paper gives a useful description of progress achieved in this field, and provides some challenges for future research. The paper is suitable for publication. I only have the following minor points for the authors to address.

1. Please consider providing the reference closer to the authors. For instance, in Section 2.2, the works by Chen and Grossman and by Caballero et al. are described and the reference is given far away from those authors. Several other examples are observed.
2. In line 390, it says “another alternative option”; use either “alternative” or “option” – it becomes redundant to use both.
3. In Section 5, it says “It is worthy of mentioning…”; please change to “It is worthy of mention…”

Author Response

The reply to Reviewer #1 has been attached as a PDF file.

Author Response File: Author Response.pdf

Reviewer 2 Report

This review summarizes optimization techniques for advanced distillations. The literature survey is well done but the presentation is not well. Especially, the boundary and scope of the review are unclear. Therefore, I recommend major revision to improve the clarity and readability.

 

My concerns are as follows:

 

1. The title of the submitted manuscript is “Advancements in Optimization Techniques for the Design and Control of Intensified Processes”. At the end of the introduction, they write “(This review aims) to present some advancements in process optimization and control techniques that are used to intensify a process. These two are totally different. If the latter is true, they need to revise the title as “Advancements in Optimization and Control Techniques for Intensifying Processes”.
2. They limit the review implicitly on the distillation. At the conclusion, they mention that “Although most of the review focuses on distillation processes, the key concepts in process intensification can be extended without lack of generality” but I disagree with this opinion. First, the advanced distillation processes they review are should be placed in the classical petrochemical plant. Plant miniaturization is one of the most important topics in the PI. The focus of the plant miniaturization is not a reduction of total annual cost but the modular flexibility, shorter lead-time for fine chemicals, use of renewable energy sources. The optimization method for tertiary distillation cannot be extended to the optimization of miniaturized modular plants for active pharmaceutical ingredients. Second, distillation is well described by equilibrium models decoupled from operating conditions such as flow rate and device shape. Many process intensification examples such as microwave reactor, fine bubble devices, rotating packed bed, microreactor, electric field, plasma technology, and membranes are not so easy. Their performance is highly dependent on the size and shape of the devices as well as operating flow rate and target systems. In addition, detailed and accurate mathematical models are not always available for such developing technologies. Thus, research and development of these process intensifications are highly device and materials oriented, and not oriented by mathematical concepts like superstructure. If the authors still want to make the distillation process as the representative of PI, they need to write a convincing story for this issue at the introduction section, not at the conclusion section. 
3. Effective use of tables is strongly recommended. They list many literature examples in sentences. Comparison of each technique is very difficult in this manner. The review focus should be on the advance. Table showing techniques with their advantage, disadvantage, and maturity in chronological order will greatly help readers to understand the advancement in this field.
4. Current figures are not informative. Figure 1: the authors mention the combination of process synthesis, design, optimization, and control although figure 1 only presents individual numbers. There is no information about combinations. Figure 2: the schematics of low aggregation are very weird. Why output is coming from the left and input going out to right? How the input fluid has N of trays? Figure 3: the image resolution is too low. What is the main difference between the inventory control loop and the quality control loop? Figure 4 & 5 can be merged. What is the interesting point of the alternative control of Figure 5? How does the alternative control shown in figure 5 intensify the process?

 

Author Response

The reply to Reviewer #2 has been attached as a PDF file.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Thank you for the careful revision.