Batch process procedure model

G. Maria and D.W.T. Rippin, Modified Integral Procedure (MIP) as a Reliable Short-Cut Method in Mechanistic Based ODE Kinetic Model Estimation Non-Isothermal and (Semi-)Batch Process Cases, Comp. Chem. Eng. 19 (1995) S709-S714. 

Here, we call all the different units. In this case, we operate in steady-state conditions for all the units, specified in the tasks before. gPROMS always solves the entire model at once. In case there is a unit or units that operate in unsteady state, we can define an operating procedure so that the products of the batch process are obtained and used in the next unit. 

Model concept in a batch process helps in understanding its hierarchical structure, and is specified in Part 1 of ISA 88. This structure will assist in dividing the systems into smaller parts. In line with the standard. Fig. VI/3.1.2-1 shows the various model types. Fig. Vl/3.1.2-1 A (or Fig. 1 of ISA 88) shows how the entire process has been divided into smaller parts for analysis of the system. As shown, the process is subdivided into process stage, process action, etc. This is a process model of batch process. The entire process can be divided in terms of models in three ways, viz. physical model, procedural model, and control activity model, as shown in Fig. VI/3.1.2-IB. Therefore, it is better to start the discussion on the three types one by one. 

It is needless to elaborate that to produce a product under batch process, e.g., ice-cream, one needs to know how to make the product (recipe), what are the tools needed (equipment), and how to run equipment (process). These are well guided through the standards. The terms discussed above and models are based on the ISA 88-01. Similarly, ISA 88 Part 2 discussed the formal representation of entities specified in Part 1, e.g., recipes, equipment, etc. The standard also specifies the information exchange requirements between recipes, process, and equipment. Later, the standard deals with a graphical representation of procedure. Part 3 deals with recipe types. The last part of the standard is... 

This is somewhat similar to batch process, discussed in Clause 3.0 of Chapter VI. The model approach of ISA 106 is shown in Fig. XII/4.0.1 -1. Here each procedure and implementation has three basic execution steps command (trigger), perform (action), and verify (check for success/failure). 

Procedure models are used to describe batch activities in a process cell. Such models include four levels of detail procedures, unit procedures, operations and phases (Fig. 2). 

As mentioned in Section 3, there are three types of control required in batch processes basic control, procedural or sequential control and co-ordination control. Basic control of a batch process is very similar to the control of a continuous process, comprising the control dedicated to establishing and maintaining a specific state of equipment and process, with the only difference being that it can be slightly more complicated as it is required to modify its behaviour based on the commands it receives. Co-ordination control manages the initialisation and movement of the batches being processed within the process cell, by direct, initial and/or modify the execution of procedural control and the utilisation of equipment entities. Procedural control is characteristic of batch processes, it directs equipment-orientated actions to take place in a ordered sequence in order to carry out a process-orientated task and consists of procedural elements, which form the procedural control model [10]. There is a functional difference between the last two types of control as indicated below ... 

A systematic procedure has been proposed to construct Petri nets for modeling the fault propagation behaviors in batch processes. In this work, a complete system model is organized according to a hierarchy of four levels, i.e. (1) the controller/operator (2) the valves (3) the process units and (4) the sensors. Every component in this system model consists of two distinct elements. One is used to characterize the equipment states and the other the input-output relations. For the purpose of reducing model construction effort, the general structure of object-oriented abbreviations is also developed to represent the PN in a user-friendly format. The effectiveness and correctness of this approach have been successfully demonstrated with a number of practical examples. 

In the studies presented the model developed for sorption equilibrium [1] was extended also to sorption kinetics. Furthermore, an approximative procedure was outlined for the transformation of equilibrixim and kinetic sorption data from batch-experiments to transport processes in model soil columns. 

Dynamic forms of these mechanistic models may be useful in either simulation, prediction or real time control. They can, among others, be used to develop start-up procedures for continuous processes. They could also be used for optimal control of batch processes, where a process variable has to follow a pre-defined trajectory. 

EC verification provides an alternative to the model of establishing a certified production QA system. Independent testing of either all devices, or a statistically representative sample of each batch, is conducted by or on behalf of the Notified Body, which then issues a certificate of conformity for the tests conducted. This is not a popular option due to the costs involved. The procedure is not capable of providing adequate assurance as to the sterility of devices. Instead, an assurance of sterility must be based on the application of a production QA system to the sterilisation process. 

The blend of the two active ingredients (B1 and B2) is slugged and then the slugs are oscillated. Slugger model and tooling are listed in the batch instructions. The thickness of the slug is specified, but no information is recorded on the slugging operation, as control of this procedure is left to the experience of the press operator. The batch record permits the use of only one screen size. Since all of the batches have been made in the same manner, this important process step will not be included as one to be studied. 

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