Batch process recipe

In a batch process, the conditions within the process are continually changing. The technology for making a given product is contained in the product recipe that is specific to that product. Such recipes normally state the following ... 

Sometimes the term recipe is used to designate only the raw material amounts and other parameters to be used in manufacturing a batch. Although appropriate for some batch processes, this concept is far too restrictive For others. For some products, the differences from one product to the next are largely physical as opposed to chemical. For such products, the processing instruc tions are especially important. The term formula is more appropriate for the raw material amounts and other parameters, with recipe designating the formula and the processing instruc tions. 

The above concept of a recipe permits the following three different categories of batch processes to be identified ... 

Batches and Recipes Each batch of product is manufactured in accordance with a produc t recipe, which contains all information (formula and processing instructions) required to make a batch of the produc t (see Fig. 8-56). For each batch of product, there will be one and only one product recipe. However, a given product recipe is nor-... 

Overview Batch processes are mostly suited to low volume high value added products that are usually characterised by common recipes, which render them amenable to sharing of equipment units. Due to their intrinsic adaptation to sudden changes in recipe, they are processes of choice in volatile or unstable conditions that have become regular in global markets. This chapter provides the background information on batch chemical processes, which constitutes the basis for the forthcoming chapters. Only the essential elements of batch plants are captured with references, where necessary, to further sources of information for the benefit of the reader. 

Any process which is a consequence of discrete tasks that have to follow a predefined sequence from raw materials to final products is a batch process. This predefined sequence is commonly known as a recipe. The primary features of any comprehensive recipe are the quantities of materials that have to be processed by individual tasks as well as the duration of each task within the recipe. The secondary features are the operating conditions of the various tasks, and in less common circumstances, the locality or geographic position of the task at hand. In processes wherein safety is of great concern, it might be necessary to perform a particular task in a designated area equipped with relevant safety features. 

In co-operation with a German chemical company, a recipe-driven batch process was modelled and simulated using PPSiM. In the simulation study, different pipeless plant scenarios were tested and evaluated. The plant under consideration produces a set of consumer care products. 

The considered batch process produces approximately 750 different products which can be divided into 9 product groups. Within the 9 product groups, the recipes only differ by the additives used. Figure 3.3 shows the average fractions of the raw materials for the 9 product groups. 

Fritz, M., Liefeldt, A. and Engell, S. (1999) Recipe-driven batch processes Event handling in hybrid system simulation. Proceedings of 1999 IEEE International Symposium on Computer Aided Control System Design (CACSD 99), Hawaii, USA, pp. 138-143. 

The scheduling problem is complicated by the fact that the coupled production of grain size fractions and the mixing in the finishing lines prohibit a fixed assignment of recipes to products. Furthermore, there is neither a fixed assignment of storage tanks nor of polymerization reactors to batch processes. 

This section describes some of the tools available for intelligent development of process cycles, such as the time-temperature cycles used in curing composites. Current industrial practice is typically limited to the use of cure cycles. The cycles are based on a series of autoclave temperature and pressure states so that traditional linear, regulatory process control methods can be used. These recipes may not be the ideal method for process control of batch processes because they do not ... 

Applications to batch processes have been less common, but there has been some work done on the use of an ANN to control autoclave curing. Joseph et al. used an ANN successfully to cure a part, reducing cure times and improving qualities, such as thickness control and void content [37], When more variables were included, however, the computational problem became intractable. This particular approach to using an ANN broke variables down into time, temperature, and pressure recipes, which, as noted in the Section 15.3.2, can lead to exponential growth of necessary training cases. 

Emulsion Polymerization A typical recipe is give in Table I. Emulsion polymerization was carried out at 60°C under a nitrogen atmosphere using a batch process. Theoretical solids content in all the formulations was 25%, and generally the conversions were better than 98%. A polyvinyl acetate homopolymer and two poly (vinyl acetate-butyl acrylate) copolymers having VA/BA composition of 85/15 and 70/30 were prepared according to the above procedure. 

Positive-displacement (PD) flowmeters are used when the total quantity of the flowing process stream is of interest or when a recipe is being formulated in a batch process. These meters operate by trapping a fixed volume of fluid and transferring that volume from the inlet to the outlet side of the meter. The number of such calibrated "packages" of fluid is counted as a measure of total volumetric flow. These measuring devices are used in both gas and liquid services. 

A particular confectionery industry problem is the long product life. A long-established product, initially made by a batch process, must retain the same qualities when prepared by a more modern continuous plant process, and a great deal of work can go into making the two products exactly the same. In general, however, the continuous plants are more effective at heating the product and produce less sucrose inversion, although, even after the recipe has been adjusted to account for this, textural differences sometimes persist. 

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