Chemical process flow simulation

In this article we are going to talk about Chemical process flow simulation, which is a process that aims at representing physical and chemical transformation through the use of a mathematical model which involves the computation of mass and energy in connection with phase equilibrium plus chemical kinetic equations and transport. This process aims to predict the behavior of a well-known structure in which some of the basic data used in composing the process are well known.

The process simulation is mainly for: 

  1. Predicting the performance of the process.
  2. Locating malfunctions
  3. Interpreting flow sheets

In a chemical process flow simulation calculation, a node is used to represent a plant’s mathematical model. The parameters are pressure, flow rate, temperature and composition of all the output streams in this process. Leaving the node can be calculated from the information on the parameters of all the node input streams.

The structure can also be represented by a system of equations in a diagraph with the condition that there is an existence of an output variable set on the system.

A chemical node diagraph is not limited because it can have more output stream, unlike other structures.

 The flow of information in a system with no recycle streams flows in a forward direction. The diagraph is referred to as acyclic, and it is easy to determine the order of the calculation of nodes.

A system that has to recycle streams has diagraph which is normally cyclic and has nodes which are within the recycle loop and are part of the cyclic net. Some nodes might be part of more than just a single cyclic net, and thus they form a maximal cyclic net made up of the interconnected cyclic nets.

There are two methods in which the calculation of systems with cyclic nets includes
1. All nodes that are in a maximal cyclic net are computed using simultaneous solutions.
This method can be efficient only if the equations can be linearized and used successfully for particular simulation programs, i.e. (7, 39, 56, 88, and 89). Still, it cannot be used for simulation programs that are general.
2. The second method is tearing the cyclic nets.
This is where starting values are guessed for a single stream’s parameters, and then the nodes along the torn stream are calculated. More than one stream has to be torn in this case.

This system is quite sophisticated, and a lot of processes have to take place for the simulation of a large network to take place entirely. For instance an efficient tearing scheme for a large system to be devised there are other steps that are required like the system is portioned to determine separate cyclic nets and an optimum tearing scheme for each is devised.

VisiMix Video

The Influence of Mixing in the Process
New methodology using VisiMix software for the purpose of checking the influence of mixing in the processes.

VisiMix Demo Operation
Learning how to input data into the VisiMix software and get results the will help us understand the influence of mixing in our processes.

Lab Experiments
Learning how to set up the relevant experiments at the lab scale, to develop the processes from an engineering point of view.