TABLE OF CONTENTS Continuous production processes are defined by the production of material in a continuous flow. Continuous processes deal with materials that are measured by weight or volume, without a discrete identity for any part of the produced material. Materials pass through different pieces of specialized equipment, each piece operating in a steady state and usually performing one dedicated part of the process. Once running in a steady state, the process is not dependent on the length of time it operates. In many cases, the same feedstock is used but with different production parameters and/or additives to make different products.
One characteristic of continuous production is that during startup, shutdown, and product switchover, the resultant product streams may not be usable product or it may have to be separately stored and reprocessed. Efficiency in these operations requires fast and repeatable startup, shutdown, and product switchovers, and this is where NS88 can be effectively applied.
Product switchover times can vary based on operator experience, and it is not uncommon to see a factor of two or three time differences between operators. Applying the NS88 pattern in these situations results in consistent product switchover times, best practices, and safer operations. Recipe procedure automation removes operational errors by enforcing rules of timing and procedure steps.
Figure 8-1 illustrates a sample continuous process within a production unit. Within continuous processes such as these, it is difficult, if not impossible, to identify S88 unit boundaries because of feedback loops and multiple output...
