Scheduling and Optimising Systems

The most efficient use of resources is a goal for most industries, but especially capital intensive industries such as pulp and paper. Efficient utilisation of resources can be aided by smart scheduling and optimisation of cost functions, to maximise profitability without generating excessive work in process, or inventory.

Scheduling Systems can be provided for short to medium term scheduling and simulation which determine the maximum plant production rate consistent with constraints on:

  • product demand and storages,
  • effluent handling throughput, 
  • raw material supply, and
  • availability of services.

These systems are intended as an aid to production coordinators, and operators, to determine the most appropriate production rates which maximise production and minimise production rate changes.

A model of the process is built graphically to define the system. With no limiting constraints, the system model will calculate production rates to achieve and maintain the levels in the intermediate storages that will best cope with unplanned shuts upstream or downstream of each storage.

If the production rates required to match product demand are outside of minimum or maximum production ranges, best use will be made of the available capacity in the intermediate storages to maintain production.

If production is limited by raw material supply or effluent handling throughput, the maximum production rate is calculated according to the available raw material.

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Philosophy

The Pro-Plan Process Scheduling System is based on the following philosophy:

  • Calculate optimum storage levels based on the probability of breakdowns, or the need to prepare for a known situation
  • Calculate the desired inflows to achieve the optimum levels.
  • Calculate the desired production rate to suit.
  • Check for raw material supply or storage constraints.
  • Check for effluent handling or storage constraints.
  • Check for availability of services, such as steam.
  • If downtime for any process is planned, calculate the maximum capacity over the period.

    Calculate the capacity required to satisfy inputs and desired levels.

    If the capacity required exceeds the maximum capacity, limit the desired production rate based on the constraint.

Improved scheduling will result in less shutdowns due to storage capacity constraints - and consequently greater plant throughput over time.

For consulting in this area, Contact Procex!

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