Operability Studies

Flex your design in real-world scenario simulations

Understand the sensitivities of your process by running multiple scenarios in a dynamic plant simulation. Flex any combination of input parameters and observe the dynamic process response. Design a robust flowsheet, specify fit-for-purpose equipment and provide stakeholders with confidence in the safety and profitability of your design.

Operability studies look at the response of the plant when input parameters are varied from design values, and might be conducted as a stand-alone investigation or as part of a HAZOP study. Dynamic process modelling is typically employed since many of the significant phenomena resulting from process deviations are transient in nature and so will not be found by solving a steady-state model.

Typical questions answered by this type of approach are: What are the peak parameter values (of temperature, pressure, particle size, flow-rate, volume, etc) as a result of a deviation? How do variations in feed or reagent characteristics affect my process? How soon after a disturbance will my process resume steady-state operation?

Simple Example Scenario

Start-up and long term behaviour of a jacketed CSTR with exothermic first-order reaction at various residence times and coolant flow-rates:

Solution A: Base case - coolant flow-rate, reaction rate constant
and reactor residence time combine to produce an oscillatory steady-state.

An oscillatory steady-state is generally an undesirable operating point and it is advantageous to understand the conditions that can lead to one. In this case a simple reduction in reactor residence time or coolant flow-rate takes the system to a new and stable constant steady-state at a high rate of conversion, shown here:

Solution B: Reduced coolant flow-rate.

Solution C: Reduced residence time.

Note that steady-state modelling of these cases would not find the Solution A steady-state at all and also would not provide any information on start-up behaviour. In the case of this reactor the peak temperature reached occurs in the transient start-up phase and it is significantly greater than the steady-state temperature - a crucial piece of design information.

We bring a personal and effective approach to every project we work on, which is why our clients keep coming back.
Director & Principal Engineer, Oliver Kloiber-Deane BEng(Chem) MSc(Math)

Our Services

Steady-State Modelling Dynamic Modelling & Simulation Process Optimisation Operability Studies

Further Info

Fidelity

The degree of fidelity to reality required of a model should be judged carefully: the solution must be sufficiently accurate to correctly answer the questions posed without wasting time modelling features that have no significant impact on outcomes. For this reason process models built over the life of a project typically range from very simple at the desktop-study stage to highly detailed at the engineering and commissioning stages. Models may then continue to be evolved during plant operation in order to optimise the process for new feed-stock, de-bottleneck for greater throughput, etc.

Workflow

Close communication with our client and adherence to client specification documents (process design criteria, process flow diagrams, control philosophy, etc) is our standard approach. Client input is typically required on a range of issues throughout a modelling project. For example process modelling during a flow-sheet development stage often uncovers issues in the process design that had not yet been considered by the design team - commonly water balance, impurities build-up and related effluent treatment issues for hydrometallurgical flow-sheets.

We also find that a period of time spent in the same physical location as the client in the early stages of modelling a complex flowsheet can speed up delivery by removing communication delays.

Deliverables

Our typical deliverable is an electronic file containing neatly formatted process simulation output data and a report that illustrates the model flow-sheet; demonstrates the model's fidelity to the client's design criteria; lists and justifies any assumptions made; and provides a brief analysis of outcomes. If necessary a section will also illustrate any process risks and sensitivities that may have been uncovered. We are also happy to supply the live model files which thereafter allows the client to view and modify the models themselves.

Pricing

Please contact us with details of your job for an obligation-free discussion and a competitive quote. For a well-defined scope of work we are happy to offer a fixed price.

Contact Us

Please contact us for an obligation-free discussion of your needs.

PO Box 3354 Newmarket QLD Australia
info@elementrescon.com.au
+61 (0)408 949 793
elementrescon.com.au