When designing a new or expanded plant, or just trying to debottleneck an existing line, an understanding of all of the planning and scheduling constraints is critical to maximize the utilization of all equipment and the corresponding return on investment. The following is an overview of my experience in this area.
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Fermentation Plant Shop Floor Scheduling
As a process engineer at Novo Nordisk, one of my responsibilities was to work with the planning group and the other manufacturing areas to schedule fermentations. This was a multiproduct, multiple fermentor batch plant, which can be quite a challenge to schedule. When I started, shop floor scheduling was done by hand with a sheet of paper and a pencil. I soon automated this with a crude Excel spreadsheet.
Manufacturing Planning and Scheduling Software Project
While at Novo Nordisk, I was the project manager of an international project team charged with selecting a manufacturing planning and scheduling software package to be used by all Novo Nordisk multi-product enzyme manufacturing plants worldwide. For this project, I compiled a functional requirements list from project stakeholders and identified critical functional requirements. We then compiled a master list of potential suppliers and screened them against the critical functional requirements. Once the list was narrowed to our top choices, we developed a standard scheduling scenario test and asked each vendor to prepare a demonstration based on the scenario. The team then made the final selection.
This was my last project at Novo Nordisk before I moved on, and my last day on the job was spent on an airplane flying home from Denmark after presenting the final recommendations of the team to senior management.
Long-Term Capacity Planning
More recently, I have worked with one of my consulting clients to do long-term planning of their capacity requirements. Starting with their forecast, bills of materials, and a set of processing times and capacities for all of their major equipment, I built a spreadsheet model that converts the forecast into the number of fermentors of each product required. This includes a typical contamination/rejection rate and provisions for any projected yield increases. The model then uses the processing times and capacities to determine the required downstream capacity and allows evaluation of adding more units like centrifuges to an existing train or adding an entirely new train. Periodically, as the client is determining their future capital investment requirements, I update this model for them to assist in their planning efforts. Eventually, we plan to migrate this model into their SAP enterprise resource planning software where most of the underlying data will be stored.
Process Simulation Modeling
The SuperPro process simulation modeling software that I use to assist clients with process development and manufacturing plant design has a powerful built-in shop floor scheduling capability for a single process. This can be used to properly size all equipment in the process for maximum capacity utilization. For a multiproduct plant, the companion SchedulePro software can upload multiple SuperPro models for different products and combine them into a single shop floor scheduling model. This allows rapid evaluation of multiple scenarios to determine bottlenecks and assure that utilities and raw material storage are sized appropriately for a variety of product mixtures.