1. PROCESS MODELLING AND SIMULATION SEM 1 (2013/2014)
PTT303 /2
PROCESS MODELLING AND SIMULATION
SEM 1 (2013/2014)
Batch Processing Modelling
(Process Scheduling, Resource and Inventory Tracking)

2. Student should be able to;
SPECIFY the process scheduling of bioprocess plant
ILLUSTRATE and ANALYZE the resource and inventory tracking

3. Course Outline Process scheduling Specifying process scheduling
Viewing scheduling & related results
Resource tracking
Inventory tracking

4. Process scheduling tools
Operating Gantt Chart
Equipment Occupancy Chart
Recipe Scheduling Information

5. Purpose of scheduling
Based on the scheduling information & annual operating system time (AOT) specified for the plant, the system will:
Make sure there is no conflict between start time & end time of processing steps
Make sure there is no conflict between the specification of annual operation time, the number of batches, plant cycle time.
Calculate the following:
Plant’s batch time
The maximum number of batches possible
Longest procedure & scheduling bottlenecking problem

6. Scheduling function in SPD
For each operation:
The process time
The setup and turnaround time
The starting time
The number of cycles (at procedure level)
For entire plant:
The AOT
The number of campaigns per year , and either:
The number of batches per year, or
The batch cycle time, or
The batch time slack

7. Important scheduling definitions
Setup Time (St):
Duration spent for preparation before the actual execution of an operation
May involve cleaning, vacuuming, setting up of equipment
Process Time (PT): duration that an equipment is in use to carry out an operation.
Turnaround Time (TT): duration that an equipment is being prepared for the next cycle
Operation Cycle Time (OCT):
Amount of time for an operation’s cycle to be
OCT=ST+PT+TT
Procedure Cycle Time (PTT): duration spent to complete an entire procedure, including all operations in the procedure
Batch Time (BT): duration from 1st operation till the end of the last operation in a single batch

8. Operation Gantt chart Batch time = 11.49 hr PCT for P-1 =10.52 hr
OCT for
FILTER-1 in
P-2 = 4 hr

9. Equipment Occupancy Chart
Procedure
cycle time
Turnaround
time
Batch time

10. Recipe Scheduling Information
Path: Task/Recipe Scheduling Information
Make this following changes:
Set number of batches per year: 20 (assuming that the equipment used by this process is used by other processes)
Set Recipe Cycle Time:12 hr
Press “Update”
Note the different changes before and after changes

11. Changes in scheduling Variables Original After recipe change
Batch time
Min cycle time
Number of batches
Batch cycle time
Time slack

12. Resources & inventory tracking
Resources (ingredient, heat transfer agent, power, labor)
Inventory ( ingredient, heat transfer agent)

13. Resource tracking (Operator)
Path; View/ Resource Consumption Tracking Chart/ Labor/ Multiple Batches…Operator
Set to display for 4 batches & fit to window
2 operators
are needed
in total

14. Inventory tracking SPD can only analyses & displays inventory
Given the following info:
40 kg of material ‘B’ are used in each batch
Suppose there is a 200 kg storage capacity for ‘B’ with an opening inventory of 100 kg
Loading rate of ‘B’ into storage: 200 kg/hr
Task: determine how often should shipments of ‘B’ be scheduled?

15. Inventory tracking
Path: View/ Resource Inventory Chart/ Ingredient (Multiple Batches)
Select ‘B’ and select the Supply Info button. Fill out the dialog as shown in figure below:
Storage capacity: 200 kg
Initial content: 100 kg
Supply mass flow: 200 kg/h
Schedule variable-10% (On-Trigger); 90% (Off-Trigger)
On-trigger & Off-Trigger settings: the supply of ‘B’ should be replenished when the inventory falls to 10% of the capacity; and halted when the inventory reaches 90% of storage capacity

16. Inventory tracking
Click OK to continue & the chart will be displayed with 2 batches. Set the number of batches to 12 by right clicking and selecting Set Number of Batches
Supply rate =
200 kg/hr 3 7 11 4 8 12
90% of
inventory =
180 kg 1 5 9
Initial content =
100 kg 2 6 10
10% of
inventory =
20 kg

17. Working session
Do the same for ingredient A, use the same storage information based on B (capacity, supply rate, etc). Display for 12 batches. Suggest a solution for the problem that occurs