Optimal batch recipes

The end customer s main benefits after commissioning of the solution described can be summarized as follows optimal production schedules with optimal batch recipes are available on demand within seconds, better overall process coordination and visibility of the process and faster recovery from disturbances through efficient scheduling. This leads to a significant increase in plant throughput and revenues. 

During normal operation of the copper plant, there are a number of regular maintenance jobs that need to be planned. They are included in the scheduling problem as additional jobs that have given release dates and due dates. These maintenance jobs can mostly be performed only when a unit is empty and not in use. The optimization approach finds the best location for each maintenance job with the least impact on production throughput and, furthermore, modifies the batch recipes such that there will be a suitable break in the operation for the equipment that must be maintained. 

Aamir, E Nagy, Z. K. Rielly, C. D. 2010 Optimal seed recipe design for crystal size distribution control for batch cooling crystallisation processes. Chemical Engineering Science 65, 3602-3614. 

Loonkar and Robinson (1972) extended the design problem to the optimal selection of semi-continuous equipment for pre-selected batch equipment that was fixed by the recipe. 

The resulting optimization problem is solved using ILOG CPLEX [4], which generates a schedule for all major process steps, as well as the main material requirements for the production (optimal recipe definition for each batch). The schedule obtained is furthermore passed on to a crane movement simulation module, which... 

Usually, for the production of small quantities of high-priced chemicals, such as in th manufacture of pharmaceuticals, foods, electronic materials, and specialty chemicals, batch fed-batch, and batch-product removal processes are preferred. This is often the case in bio processing, for example, when drugs are synthesized in a series of chemical reactions, eacl having small yields, and requiring difficult separations to recover small amounts of product This is also the case for banquet facilities in hotels, which prepare foods in batches, and fo many unit operations in the manufacture of semiconductors. As discussed in Chapters 3 am 4, these processes usually involve a recipe, that is, a sequence of tasks, to be carried out h various items of equipment. In the latter sections of this chapter, variations on batch proces schedules are discussed, as well as methods for optimizing the schedules. 

As mentioned earlier, it is common to specify size factors and input/output ratios as known constants when defining recipes. Also, batch times for each task are often specified as constant, or as known functions of the batch size. These can be determined by optimizing the operation of each equipment item, as discussed in Section 12.2. 

Models are useful for process optimization, especially when dealing with highly nonlinear problems such as grade changes/switchovers in batch, semibatch and continuous reactors. Extensions to recipe modifications and design are another application. 

A substantial number of chemical, food, pharmaceutical and metallurgical industry rely on batch-wise production processes. The dynamic and complicated character of the recipe steps and the equipment can lead the process to reach unsafe conditions. The accurate and appropriate modeling of the batch process and the recipe is the focus of this research. In particular, the goal of this paper is to present the modeling for simulation and optimization of safety constraints related to a polymer batch process. 

The polymerization takes place in the presence of catalysis. The objective of the batch process is to maximize production of the product by controlling the amount and timing of added reactants along with the reactor s temperature profile. Of course, this objective is conditional on satisfying certain safety constraints. In the initial recipe the feedrates for components A and B, the temperature and the catalyst charge, which are also the decision variables in the optimization, are set. 

Since early 1990 s Petri Nets (Condition and Event Petri Nets) have been used for modelling and control to model the batch system. Yamalidou and Kantor [15] have studied different techniques and the use of High-level Petri Nets for modelling and optimal control of discrete events in chemical processes. In Kitajima et al. [16] a systematic procedure to create a colored Petri Net model from a SFC and various information sources, recipe, equipment information and batch schedule has been proposed [17]. 

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