Process Scheduling, Resource & 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: i. The process time ii. The setup and turnaround time iii. The starting time iv. The number of cycles (at procedure level)  For entire plant: i. The AOT ii. The number of campaigns per year, and either: a. The number of batches per year, or b. The batch cycle time, or c. 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 1 st operation till the end of the last operation in a single batch

Operation Gantt chart PCT for P-1 =10.52 hr OCT for FILTER-1 in P-2 = 4 hr Batch time = 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 VariablesOriginalAfter 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 % of inventory = 180 kg 10% of inventory = 20 kg Supply rate = 200 kg/hr Initial content = 100 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