Batch process plants types

Another option is modeling approach, where a qualitative model is developed to include batch process. One of the objectives of such models is to concentrate on the understanding of how hazardous scenarios develop in batch processing plants. For this, different types of information can be integrated within a model to allow reliable prediction of tbe behavior of a system. Software tools are used for modeling of batch plant systems viz. HAZOP expert—LDGHAZOP. Based on the... 

So far plants have been considered involving a single product. However, batch processes often produce multiple products in the same equipment. Here two broad types of process can be distinguished. In flowshop or multiproduct plants, all products produced require all steps in the process and follow the same sequence of operations. In jobshop or multipurpose processes, not all products require all steps and/or might follow a different sequence of steps9. 

Leaching has in the past been carried out mainly as a batch process although many continuous plants have also been developed. The type of equipment employed depends on the nature of the solid—whether it is granular or cellular and whether it is coarse or fine. The normal distinction between coarse and fine solids is that the former have sufficiently large settling velocities for them to be readily separable from the liquid, whereas the latter can be maintained in suspension with the aid of only a small amount of agitation. 

In a retrofit batch design, we optimize the batch plant profitability defined as the total production value minus the cost of any new equipment. The objective is to obtain a modified batch plant structure, an operating strategy, the equipment sizes, and the batch processing parameters. Discrete decisions correspond to the selection of new units to add to each stage of the plant and their type of operation. Continuous decisions are represented by the volume of each new unit and the batch processing variables which are allowed to vary within certain bounds. 

Batch production is usually carried out in relatively standardised types of equipment, which can easily be adapted and if necessary reconfigured to produce many other different products. It is particularly suitable for low volume, high value products such as pharmaceuticals, polymers, biotechnologicals or other fine chemicals for which annual requirement can be manufactured in few days or few batches in an existing plant. The flexibility of the production arrangements can also cope with the fluctuations or rapid changes in demand, which is often characteristic of products of this type. Other factors (Shah, 1992) which favours batch processing are ... 

In this chapter we discuss important issues as we move from laboratory to pilot plant and manufacturing. A review of batch process operation and pharmaceutical research is covered in Section 3.1.2, followed by laboratory vessels and reaction calorimetry in Section 3.1.3. In Section 3.1.4 heat transfer in process vessels is presented, including the effect of reactor type and heat transfer fluid on the vessel heat transfer capability. In Section 3.1.5 dynamic behavior based on simulation studies is discussed. 

There are essentially two different types of large-scale US-assisted chemical plants batch and flow type. Sometimes, the flow system is an integral part of the batch processing equipment, where it acts as a loop attached to the main vat. 

In some batch plants, several trains of identical equipment are operated in a sequence that allows some degree of heat recovery or enables downstream equipment to operate continuously. In this type of plant the time allowed for each operation in the sequence is optimized so that an overall schedule for the plant can be developed. Scheduling of batch processes is described in Biegler et al. (1997). 

For upgrading plants, the equipment must be leak-proof and under vacuum to prevent tritium from escaping. There is a cleanup unit to avoid contamination. The electrolysis employed for the final enrichment or upgrading is a batch process and is carried out in a tank-type cell. The anode is usually made of nickel. 

Process intensification (PI) offers several opportunities to improve energy efficiency and reduce environmental impact [92]. Many chemical reactions currently carried out as batch processes in stirred tanks could be carried out in continuously operated, intensified reactors such as spinning disc or oscillatory baffle types. The plant used for separations can be made highly compact, and even for large-scale plants (nitric acid production) the concept of pocket-sized plant has been introduced to reduce energy needs in the process [93]. PI is thus a key element... 

Integration of a microreactor (StarLam 3000IMM microreactor) in an existing production plant (two-step batch process) has also been reported the reaction type is unveiled in the paper by Kirschneck and Tekautz- Installing a microreactor in the first reaction step leads to an increase in the capacity of the macrobatch process. An overall throughput of 3.6 ton/h has been achieved and the system has been running in production for more than a year. 

Instruments used on steam boilers included pressure and flow indicators and controllers, carbon dioxide recorders, speed controls for mechanical stokers and liquid level indicators and controllers. As chemical manufacturers began to abandon batch processing in favour of continuous processing plants and also paid greater attention to fuel efficiency the possible uses of the type of instruments employed in steam raising plant must have become apparent. ... 

Systematic methodologies to generate new design alternatives have also been proposed (Halim and Srinivasan, 2008, 2009). A different approach where indicators, heuristics, and process model are combined to provide decision support in retrofitting of chemical batch processes has also been developed (Simon et al, 2008). The developed framework considers the identification of improvement opportunities in a batch plant by considering first the product market situation. The batch plant analysis is structured on three levels the plant, the process, and the unit operation level, respectively. The analysis of these levels is based on indicators which are of various types and specific for each analysis level. These indicators are linked to heuristics which are used to identify the retrofit actions. 

Continuous, steady-state operation is often regarded as the ideal procedure for many types of process plant equipment, but this is not always true for crystallization processes. Batch operation often offers considerable advantages, such as simplicity of equipment and minimization of encrustation on heat-exchanger surfaces. In many cases, only a batch crystallizer can produce the required crystal form, size distribution, or purity. On the other hand, the operating costs of a batch system can be significantly higher than those of a comparable continuous unit, and problems of product variation from batch to batch may be encountered. 

The oscillatory baffle reactor/oscillatory flow reactor (OBR/OFR) types are seen as for niche applications, where one wants to convert a long residence time batch process to a continuous one. In the case of biodiesel, Dr Harvey indicates that a conversion could be carried out in 10 minntes, compared to 1-6 hours in continnons indnstrial processes. One variant is shown, by means of a flow diagram, in Figure 10.20, while Figure 10.21 shows components of the OFR. The aim is to make the plant portable so that it will fit into a standard shipping container. The unit could be sold worldwide to, for example, formers to produce their own fuel locally. 

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