Reference no: EM132535921 , Length: 10 pages

CHEN3003 Process Synthesis and Design - Curtin University

Objective 1: Find and summarise information about a specific product and its manufacture.

Objective 2: Analyse a nominated manufacturing process from a process synthesis point of view.

Objective 3: Construct a Hysys simulation for the given process, clearly documenting the assumptions and choices made, and reflecting on its limitations.

Objective 4: Perform an individual study on a process synthesis and design topic of your choice, explaining its benefits and scope, your method, the results and their implications.

Objective 5: Present the information in professional reports

PRODUCTION OF STYRENE

The product for the project is styrene, C6H5CH=CH2. The optimised process flowsheet by Luyben (2011) in Chapter 15, Section 15.5, Figure 15.8 of his book Principles and Case Studies of Simultaneous Design is the focus of this project. The process involves one main reaction- the dehydrogenation of ethylbenzene to styrene-although there are several side reactions, including some with the large quantity of steam that acts as a heat carrier and diluent. The process has a two-stage reactor, a three-phase separator, two distillation columns and a few other equipment items. You'll be asked to analyse and simulate it. Luyben's flowsheet can be found in the first link in the Project Information section of the Reading List on Blackboard. Luyben's book chapter begins with an unoptimised version of the flowsheet (referred to as the Vasudevan flowsheet) in Figure 15.1 on page 292, but this is not the one to be simulated.

This project will involve you searching the literature for product and process information; for example, in a professional reference like Ullmann's Encyclopedia of Industrial Chemistry, from styrene manufacturers' websites, and via professional chemical business sources like ICIS Chemical Business. You are not expected to pay for commercial market survey reports. It's expected that you'll use multiple information sources to deepen your understanding and analysis, even if you take most of your information from a single source. You'll also likely need to read more about a model of process synthesis - either Smith's (Smith, 2005; Foo et al., 2005) or Douglas' (Douglas, 1985) - as covered in Week 1 lectures. See the Reading List on Blackboard for links to Ullmann and other sources.

PROJECT TASKS

Please perform the following tasks and write a report on the work conducted.

Part 1. Product and process information (Group work)
Please provide the following background information about styrene (suggested length 2- 5 pages):
(a) Brief description, typical specifications of commercial grades and commercial applications of the product. Please note that specifications are not properties.
(b) Business information on the product, such as major producers, trends in worldwide production capacity, recent industry news, new projects, typical plant capacities, and historic and current prices, and technology developments. Please include at least two recent business sources and one recent research / technology development article, with recent meaning, say, 2017-2020.
(c) Table that describes and compares at least one alternative manufacturing process for styrene with the optimised Luyben process. Please give preference to current commercial processes. However, you can include superseded historical processes and processes that are not commercialised.

Part 2. Analysis of the Luyben process (Group work)
Please analyse the optimised flowsheet by Luyben from a process synthesis viewpoint (suggested length 3-6 pages):
(a) Classification of the flowsheet into generic flowsheet blocks (such as Reactor Feed Preparation). Show the generic blocks by drawing your own generic block flow diagram of the process. Explain the reasoning behind your choice of blocks and classification.
(b) For the optimised Luyben process, use either Smith's onion model or Douglas' hierarchical model of process synthesis to interpret the issues encountered, decisions made and possible alternatives that you think would have been considered by the process designers. Please make sure you state clearly which synthesis model you are using. Show your analysis in a table, where the layers or levels of consideration are shown in the rows and the issues, decisions and alternatives are shown in the columns. You should use a combination of referring to relevant literature and your own ideas. For the reactor layer or level, for example, you could explore among other questions:
• Issues: What are the main factors that should be considered in designing the reaction section of the process? Which are the more important? Are there any specific issues about making styrene?
• Decisions: What reactor configuration did the flowsheet designers select? How did they decide to control the reactor temperature? How was by-product formation handled?
• Alternatives: Are there any reasonable alternatives to the given reactor design that you think the designers might have considered? Why might they have rejected them? What do you think would be worth exploring further?

Part 3. Process simulation and review (Group work)
You are asked to replicate the optimised Luyben flowsheet in Hysys as close as reasonably possible, and compare your simulation with Luyben's work. Replicating existing results is often used to build confidence that your methodology and parameter values are correct before undertaking further studies that you are more interested in. However, it is almost inevitable that you will not be able to replicate all the flowsheet results exactly. Please don't spend an excessive amount of time trying to match Luyben's work. As you create the simulation, please keep notes about how you are approaching it as you'll be asked to explain that in your report.

This part of the work should include the following (suggested length 10-15 pages, excluding the Input Summary):

(a) Construction of a steady state simulation of the optimised Luyben process in Hysys with the following restrictions:
• Rigorous PFR models must be used for the reactor units with the reaction set and kinetics given in Luyben Section 15.2.1.
• Shortcut Columns (with Component Splitters or similar, if needed) must be used

for the distillation columns. Please do not use fully rigorous columns for the group portion of the work.
(b) A clear image of the Hysys flowsheet.
(c) Stream tables for the material and energy streams, including compositions expressed in mole fractions.
(d) An Input Summary generated by Hysys (to be placed in an appendix).
(e) A table that outlines the simulation created:
• Assumptions and decisions made
• Any justifications for them
• Any comments about their implications
The simulation elements covered should include not only the equipment, but also the list of species, thermodynamic method and similar.
(f) A table that reviews, in order of decreasing importance, the major differences between the simulation and Luyben's optimised flowsheet results. Minor differences should be excluded from the table, but can be briefly noted in the text.
(g) A summary of the history of constructing the simulation, and a review of the main technical challenges encountered and how the group overcame them or tried to overcome them.

Part 4. Individual study on a process synthesis and design topic
Before selecting a topic, please think carefully about the information or data you might need, how it could be obtained or approximated, and have a go at finding it before making a final decision about what topic you do. Most importantly, consider your level of access to Hysys, and what limits that will place on you. Some of the topics may require further research and self- study. Original thinking is strongly encouraged in this individual study. For some topics you may need to replace some of the simplified units by rigorous units. Each person needs to write up their individual study in an individual report, which should not exceed 15 pages.

Please note the following important points:
• The study needs to be quantitative and must involve using the Hysys styrene simulation developed by the group. If you have limited Hysys access, please check with your lecturer about the topic and approach you are planning to take.
• The intended study and the proposed methodology have to be appropriate. A study, no matter how thorough, that investigates something unhelpful or applies an unsuitable method will not gain a good mark. Please check with your lecturer if you are unsure.
• Luyben's chapter contains examples of studies like ones you may do, but you can't simply repeat Luyben's work. Plantwide control should generally be avoided as that has been already been studied by Luyben.

You are free to select any one of the topics here to investigate the process further; however,
each person in your group must do a different study:
• Checking the appropriateness of the property package used, its alternatives and improvement.
• Comparing Luyben's reaction set and kinetics with Turton's (see extract from Turton's book on Blackboard under Assessments - Project), or another one for ethylbenzene dehydrogenation.
• Alternative reactor configurations and operating conditions, possibly including different temperature control methods.
• Rigorous simulation of a distillation column and exploration of its behaviour.
• Alternative separation systems, including different separation processes and/or different column sequences.
• Heat exchanger network analysis, synthesis and implementation.
• Comparing the set-up and capabilities of simulating the process, or parts of it, with Hysys compared to another simulator, such as the free open-source simulator, DWSIM
• Questioning and exploring some of the decisions related to the reactor-separator- recycle structure of the flowsheet.
• Economic analysis, including sensitivity and scenario analyses. The Aspen Economic Analyzer may not work effectively, so manual calculations may also be needed.
• Investigating and improving the sustainability of the process.
• Exploring process intensification options and their quantification, with simulation if possible.
• Another topic of your choice related to process synthesis and design that interests you. You can be creative here. This option is particularly encouraged, but you must check with your lecturer for the topic's suitability before starting the study.

For your selected individual study please:
(a) Clearly outline the intended scope of the study. Explain the significance and potential benefits of conducting it. Suggested length: 0.5-1 pages.
(b) Describe the methodology you will use for conducting the study, referring to the literature as appropriate. Suggested length: 1-2 pages.
(c) Show the results of the work performed: flowsheets, tables, graphs, etc.
(d) Discuss the results with respect to the literature if possible, including the reasons for the behaviour, the implications, the limitations of the study and recommendations coming from the work.
(e) Reflect on the project overall - both group and individual tasks, both technical and non-technical issues, including working remotely. What are the main lessons or insights you personally gained from the project? How did you approach working remotely? Realistically, what will you try to do so you can work more effectively in the future? Suggested length: 1 page.

Attachment:- Process Synthesis and Design.rar