Multi product plant

MPP Multi Product Plant or Multi Purpose Plant ... 

In general, the required production rates of these more sophisticated materials are orders of magnitude less than those of the commodity materials referred to earlier. Some will be made in dedicated plant but many others may be manufactured in multi-product plant, which present new problems in the scheduling of efficient production. These include ... 

Multi-product plants allow the production of a range of products with similar synthesis steps (usually a product group). Individual units are combined according to the production process of the product group. 

Multi-product plant (must have adaptable safety system)... 

The production of the API and finished dosage form is required to comply with GMP regulations discussed in Chapter 9 and Section 10.2. The quality system, quality control and validation of equipment and processes have to be developed and adhered to in the manufacturing process. Proper records and documentation are required to be kept in the forms of batch records, test records and manufacturing procedures. Reaction vessels and associated equipment must be calibrated, validated and cleaned to acceptable levels before being used this is especially the case for multi-product plants where more than one API is manufactured. 

Relief and disposal systems are difficult to modify once installed. Therefore, the characteristics of future processes should be considered, as far as possible, in the case of multi-product plants or development units. 

The fine chemical industry is often characterized by small-scale plants producing a variety of chemicals using frequently hazardous starting materials and extreme conditions. Products are commonly manufactured in a batchwise, multi-product plant provided with a substantial amount of multi-purpose equipment. Typically, the production volume is not large, say less than 10 kt p. a., although this is not a scientific boundary. 

In the bulk chemicals business, where dedicated plants producing only one product are the norm, the optimisation of production through a combination of chemistry and plant design is much more straightforward than in the fine chemicals industry where multi-product plants are the norm. Volumes of individual products required by the market do not always permit the justification of dedicated plant. Consequently compromises have to be made in process operations to allow certain chemistries to be carried out on pre-established plant configurations. It is in this latter area where the talented process development chemist can make most impact on process optimisation and consequent waste minimisation. 

The scheduling problem in single-stage, parallel unit, multi-product plants is considered. Customer orders, each composed of only one product, are to be processed in a subset of the available processing units. Total production time is chosen as the objective to be minimized. The model accounts for a number of logical physical constraints, which are likely to occur in practice, such as follows ... 

A polymerization reactor often produces several grades (in terms of composition and viscosity) of the same polymer and therefore the control strategy must be easily adapted to a multi-product plant and in some cases to on-line grade transitions. In the case of a multi-product plant it may be necessary to operate the reactor in terms of rather short campaigns in order to noinimize the finished-product inventory and thus the working capital. In these cases the reactor control system must be designed in such a way as to achieve fast startups while minimizing off-specification polymer formation. 

From diese various estimates, die total batch cycle time t(, is used in batch reactor design to determine die productivity of die reactor. Batch reactors are used in operations dial are small and when multiproducts are required. Pilot plant trials for sales samples in a new market development are carried out in batch reactors. Use of batch reactors can be seen in pharmaceutical, fine chemicals, biochemical, and dye industries. This is because multi-product, changeable demand often requues a single unit to be used in various production campaigns. However, batch reactors are seldom employed on an industrial scale for gas phase reactions. This is due to die limited quantity produced, aldiough batch reactors can be readily employed for kinetic studies of gas phase reactions. Figure 5-4 illustrates die performance equations for batch reactors. 

In particular results on tank capacity are a typical output of simulations on the plant engineering level. It could be argued that these results may be obtained without simulation as well and this is true as long as the stochastic impact on supply and demand is within certain boundaries. As soon as the facility needs to be able to handle stochastic supply and demand with significant variations static calculations reach their limits. These limitations become even more critical if a multi-product process is analyzed as quite often is the case. 

The scheduling of the production of polymers in a multi-product batch plant (see Figure 9.13) is investigated here as a real-world case study. The reader is referred to Chapter 8 for a more detailed description. 

PET is produced continuously on a large scale as well as in small-sized batch plants. Currently, batch plants are mainly used for specialities and niche products. Batch plant capacities span the range from 20 to 60 t/d. Depending on process conditions, process technology and the desired PET grade, six to ten batches per day are commonly manufactured, each with a capacity of between 1.5 and 9.01. Batch plants are often designed as multi-purpose plants in which also PBT, PEN and different co-polyesters are produced. 

Jordan and Graves (1995) analyze volume flexibility that can be achieved via product-plant assignment choices in a multi-plant, multiproduct production network when faced with uncertain demand. Based on a 10 plants/10 products example they demonstrate that, if correctly designed, a network with partial flexibility can yield almost the same volume flexibility benefits as a totally flexible network where all plants are able to produce all products. Their recommendation is that products should be allocated to plants in a "chain pattern" with the complete network ideally creating a single chain instead of several shorter chains (cf. Fig. 5). For more complex networks their recommendation is to equalize the number of plants a product is directly connected to and the number of products to which each plant is directly connected and create a circuit that encompasses as many plants and products as possible. 

Multi-purpose plants combine different equipment units with flexible piping systems. They allow production of a broad range of products that vary considerably with respect to number and type of synthesis steps. 

In specialty chemicals, the majority of plants are multi-product or multipurpose plants operated in batch mode. Only a relatively small proportion of products is produced in continuous production plants. This might change however, once current development activities ongoing in the area of flexible, continuous production technology for small production volumes (micro-reaction technology) find their way into industrial production systems.13 So far, this technology is mostly employed in pilot-plant - scale production trials, but further improvements are to be expected in the near future. 

Fleischmann et al. (2006) provide a global production network planning model used at BMW that extends the simpler load planning model proposed by Flenrich (2002). The model is a multi-period, multi-product model with an objective function that maximizes the pre-tax net present value of the network. It includes decisions on product-plant allocation, production volumes, material sourcing volumes by supply region, structural and product-specific investments and use of overtime capacity. A major contribution of the model is the incorporation of the time-distribution of investment expenditures typically observed in automobile production networks. While tariffs are included in the transportation costs, the model does not consider further aspects of international trade such as currencies, duty drawbacks or local content rules which play a major role in practice. 

Within each plant class to be considered the production process consists of a number of chemical and/or physical tasks. While the type and/or quantity of input factors such as raw materials and utilities might differ significantly between products, the characteristics of the production process within a single plant class are usually similar (except for multi-purpose plants). Therefore, the activities taking place within a single plant class can normally be combined for strategic planning purposes. The overall capacity of a plant is then determined based on the "bottleneck" (usually the ma-... 

Summary The use of the on-line FT-Raman spectroscopy for monitoring a multi-step hydrosilylation reaction combines all the advantages of an on-line analytical tool (like real time measuring results, a direct view into the reaction, and no off-line sample collection) with the requirements for the application of technology in production plants, e. g., low calibration effort within a wide temperature range, stable calibration, simple system handling for the operator, small sized equipment at the reaction vessel, and no contact with the reaction media. 

We have noted earlier that a refiner or fuel processor must live in an uncertain environment. He is subject to the vagaries of the supply of crude, the requirements of the market, and the perpetual question of the future markets for residual fuel. We have developed a processing approach—using the H-Oil process— which provides the degree of flexibility necessary to cope with this uncertain environment. A schematic flow diagram of such a multi-purpose plant is shown in Figure 8. The basic feature of this plant, which has been designed for the production of 0.3% sulfur fuel oil from various atmospheric residues, is its flexibility with respect to feedstock, product specifications, and future alternative uses of the plant. 

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