Determination of the optimal conditions, bottlenecks or sensitivity of existing processes to process changes are the most essential uses of simulation software. CHEMCAD is a comprehensive process simulation software, which offers a process optimization tool for both steady state and dynamic simulation conditions.
CHEMCAD combines steady state and dynamic simulation and optimization of processes. The Process Optimizer is a built-in CHEMCAD tool which can be used for both steady state and dynamic process optimization. With the process optimization tool of CHEMCAD, you can minimize or maximize a stream or UnitOp variable with just a few clicks.
The process optimization can be performed for specific independent variables and constraints. Once run, CHEMCAD performs a numerical search according to the optimization method chosen by the user. When CHEMCAD determines the maximum or minimum of the objective function the solution can be saved. The optimization routines offered by the tool are: Generalized Reduced Gradient, Successive Quadratic Programming, and Simultaneous Modular SQP.
The steps of steady state optimization in CHEMCAD are quite simple. Once a steady state simulation is built with a converged solution, objective function can be defined by going through the optimization dialog. First, the objective function, and which action to perform on the flowsheet variable should be defined. Then the independent variables can be specified, considering which results would be interesting for the existing flowsheet. If there are any constraints on the flowsheet variables, they can be added to the optimization specifications. CHEMCAD Process Optimizer can take up to 120 independent variables and 120 side conditions into account.
The application of dynamic simulation has become more and more widely used in the process industries over the past years. The orientation towards dynamic simulation is mainly created by the expectations of the competitive markets by the producer companies. As the markets get more competitive the more strict specifications and regulations become. This demand for dynamic simulation was promoted by the development of powerful commercial modeling tools for dynamic simulation, such as CC-DYNAMICS. As the application of dynamic simulation became more common, dynamic optimization has also become an important tool for making important engineering decisions. CHEMCAD Process Optimizer is one of these tools when applied on dynamic simulations in CC-DYNAMICS.
Now, you have a unique chance to demonstrate the use of dynamic optimization in CHEMCAD. Process Simulation Cup 2017 will introduce you to an optimization task where you will discover the easy application of the process optimization tool. The task is based on a real-life case study what gives you a valuable industry exposure.
In PSC2017 task biogas can be fed to block-type thermal power stations (CHP) to produce heat and electricity required on-site the fermentation plant. Surplus electricity is exported to the national grid. This local usage of the biogas does not require expensive gas cleaning (see PSC2016), but it has the disadvantage that the storage capacities for gas as well as for electricity are extremely limited. Hence, a control structure is required to handle surplus production of gas and limits in the intake capacity of the national grid.
In PSC2017, two possible disturbances to a steady state operation of the CHP’s are evaluated. Scenario 1 considers a slow but continuous increase in the fermenter's gas production while in scenario 2 a sudden shutdown of one of the three CHP’s is simulated. The goal is to optimize the controller settings so that the amount of gas sent to the flares is minimized (scenario 1) and an opening of the safety valve is avoided or at least kept as short as possible (scenarios 1&2). Your task is to find controller parameters so that even less gas must be burnt in the flares, but don’t forget to keep a look at the safety valve! Need more details? Browse our website!
JOIN THE CLUB - DO - PROCESS SIMULATION CUP!
9 November 2017