Batch process control - The College of Engineering at ：间歇过程控制工程学院.ppt

Batch Process Control Introduction Sequential and logic control Control during the batch Run-to-run control Batch production management Introduction Batch operation is very common in the specialty chemical, pharmaceutical and materials processing industries Multiproduct batch plants produce a range of similar products using the same equipment Batch control is particularly difficult because there is no steady-state operating point and processes operate over a wide range of conditions Batch process control systems involve sequencing of different process steps and control during the batch Run-to-run control uses experience from previous batch runs to improve the current run Batch plant scheduling and planning are used to manage the production of different products Batch Distillation Example Batch Control Systems Sequencing and logic – sequencing of control steps according to a predefined recipe Control during the batch – tracking of predetermined setpoint trajectories Run-to-run control – end-of-batch measurements are used to improve control of next batch Batch production management – planning of production needs and scheduling of product campaigns Sequential and Logic Control Control of batch unit operations involves the proper sequencing and execution of specific steps Sequential logic can be represented in several ways, such as information flow diagrams Information flow diagrams can be translated into digital logic diagrams to be executed by programmable logic controllers (PLCs) PLCs can execute sequencing operations are well as standard PID control algorithms PLCs are the key control hardware used in batch plants Batch Sequence Control Example Control During the Batch Execution of sequenced operations often involves feedback control of specified outputs Batch control is challenging because there is no steady-state operating point and processes operate over a wide range of conditions Tracking of predetermined setpoint trajectories is often required Process nonline