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)

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

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

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

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

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

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

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

Equipment Occupancy Chart Procedure cycle time Turnaround time Batch time

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

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

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

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

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?

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

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

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