engineering

Process flowsheeting

Process flowsheeting is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Process flowsheeting rather than just read about it. In short: Process flowsheeting is the use of computer aids to perform steady-state heat and mass balancing, sizing and costing calculations for a chemical process. It is an essential and core component of process design.

Key takeaways

Process flowsheeting belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Process flowsheeting to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Process flowsheeting from memory before moving on to harder problems.

Reference excerpt

Process flowsheeting is the use of computer aids to perform steady-state heat and mass balancing, sizing and costing calculations for a chemical process. It is an essential and core component of process design. The process design effort may be split into three basic steps

Synthesis Analysis and Optimization.

Synthesis Synthesis is the step where the structure of the flowsheet is chosen. It is also in this step that one initializes values for variables which one is free to set.

Analysis Analysis is usually made up of three steps

Solving heat and material balances Sizing and costing the equipment and Evaluating the economic worth, safety, operability etc. of the chosen flow sheet

Optimization Optimization involves both structural optimization of the flow sheet itself as well as optimization of parameters in a given flowsheet. In the former one may alter the equipment used and/or its connections with other equipment. In the latter one can change the values of parameters such as temperature and pressure. Parameter Optimization is a more advanced stage of theory than process flowsheet optimization.

Plant design project The first step in the sequence leading to the construction of a process plant and its use in the manufacture of a product is the conception of a process. The concept is embodied in the form of a "flow sheet". Process design then proceeds on the basis of the flow sheet chosen. Physical property data are the other component needed for process design apart from a flow sheet. The result of process design is a process flow diagram, PFD. Detailed engineering for the project and vessel specifications then begin. Process flowsheeting ends at the point of generation of a suitable PFD. General purpose flowsheeting programs became usable and reliable around 1965-1970.

See also List of chemical process simulators CAPE-OPEN Interface Standard Process simulation

References

Westerberg A. W., Hutchinson H. P., Motard R. L., and Winter P., (1979), "Process Flowsheeting", Cambridge Universities Press, ISBN 0-521-22043-2 Veverka V. V., and Madron, F. (1997), "Material and Energy balancing in the Process Industries", Elsevier, ISBN 0-444-82409-X Babu, B. V.(2004), "Process Plant Simulation", Oxford Universities Press, ISBN

External links Process flowsheet development using process simulation software

Worked examples

Example 1 — a first encounter with Process flowsheeting

Start with the simplest possible case. Write down what Process flowsheeting claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Process flowsheeting before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Process flowsheeting ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Process flowsheeting

In research: Process flowsheeting appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Process flowsheeting in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Process flowsheeting is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chemical process engineering, Industrial processes, Material flow, so understanding it makes those chapters shorter.
In everyday life: Look for Process flowsheeting outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Process flowsheeting in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Process flowsheeting means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Process flowsheeting out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Process flowsheeting in simple terms?

Why does Process flowsheeting matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Process flowsheeting?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Process flowsheeting.