Dynamic Centrifuge Example Project

Navigation: User Guide ➔ Dynamic Example Projects ➔ Dynamic Centrifuge

---

Dynamic Sugar Centrifuge Example Project

Note: Available from Build 139.37057. This example no longer requires the Sugar Add-on Species Properties Model

Discussion Page Dynamic Batch Process Modelling

Project Location

..\SysCADXXX\ExamplesDynamic\Sugar Centrifuge Example.spf

Features Demonstrated

1. How to set up batch operation using cycle times and use of a state machine using a General Controller.
2. Scheduling multiple units to run at staggered times.
3. Use of Noise Controller to implement feed flow rate fluctuation over time
4. Use of PID Controller to control blender compositions and tank levels
5. The use of a Makeup Block to control blender compositions.
6. The use of General Controller to control tank level by on/off control of feed.
7. The use of Inbuilt Level Control to control tank level by varying outlet flow.
8. Use of Dynamic Fill, Dynamic Bars and Annotation Table to visibly display some parameters on the flowsheet, for example, tank level.

Brief Project Description

This is a straightforward example illustrating how to set up and run multiple batch centrifuges with predefined cycle times.

This simulation can assist in surge, availability, and capacity studies. The user may adjust the nominal feed rate to the massecuite feed tank, may turn off or on individual centrifuges, and may make other equipment and operation parameter changes to see their impact on area performance. The GC_Project General Controller reports the average time centrifuges have spent waiting to be filled.

Project Configuration

Massecuite is a mixture of crystalline sucrose, aqueous sucrose, some impurities, and water. The batch centrifuges in this project separate massecuite into crystalline sucrose (the cake) and the syrup (filtrate) using a water wash. The flow of the massecuite to the system is varied by the Noise Controller using a user specified mean and standard deviation. There are also level and composition variables controlled by a PID Controller. Each of the eight centrifuges operates a staggered batch process that is controlled by a General Controller.

The batch operation of each centrifuge can be defined by 5 unique states:

• Empty
• Fill
• Spin
• Wait
• Off

In this example, each state of the process is defined as such:

• During the Empty state, the contents of the fugal are emptied as wet cake. Syrup water is added to the cake to control the mixture to a target Brix value.
• During the Fill state, the batch feed of Massecuite to each train of fugals is set using the Batch Method on the Connect tab page of the Massecuite Feed Tank. The Massecuite feed is sent to the next available fugal in the train by setting the splits in the upstream Tie models using the Mass Frac split flows model.
• During the Spin state, the total flow of wash water required is set on the Connect tab page of the Wash Water Tank. The wash water flows to each fugal is set using the Mass Flow split flows model. The solids are prevented from leaving the fugal using the Block Solids Filter Method, set on the Connect tab page.
• During the Wait state, the centrifuge is empty and ready to fill.