Production-scale Case Study

In this section we demonstrate the performance of the proposed model on an industrial-scale case study. Instead of considering the full scale petrochemical network which may have limited application, we consider a special case of the integration problem. Although the proposed formulation covers the full scale refinery network and petrochemical systems, the case study will consider the integration of a petrochemical complex for the production of polyvinyl chloride (PVC) with a multi-refinery network. PVC is one of the major ethylene derivatives that has many important applications and uses, including pipe fittings, automobile bumpers, toys, bottles and many others (Rudd et al., 1981). 

Mass indices and environmental factors (equations (5.1) and (5.2)) have been introduced in Section 5.1. For confidentiality reasons, neither chemical names nor exact quantities are specified concerning the industrial case studies. Instead, masses are expressed relatively to input amounts at the laboratory scale. The imit (kg kg ) expresses how many kilograms of substance are needed to produce one kilogram of product. Abbreviations used in captions of the figures are explained in Box 5.2. 

Case study 4 Process scale up and resource efficiency of an industrial product... 

In some cases, the changes in the recipe from pilot to operation scale are substantial. In Case study 4, the introduction of a second solvent is accompanied by a better yield, at the expense of a five-fold higher sewage production. Consequently, raw material demand to produce one kilogram of product is diminished, and the introduction of a second... 

This chapter contains a discussion of two intermediate level problems in chemical reactor design that indicate how the principles developed in previous chapters are applied in making preliminary design calculations for industrial scale units. The problems considered are the thermal cracking of propane in a tubular reactor and the production of phthalic anhydride in a fixed bed catalytic reactor. Space limitations preclude detailed case studies of these problems. In such studies one would systematically vary all relevant process parameters to arrive at an optimum reactor design. However, sufficient detail is provided within the illustrative problems to indicate the basic principles involved and to make it easy to extend the analysis to studies of other process variables. The conditions employed in these problems are not necessarily those used in current industrial practice, since the data are based on literature values that date back some years. 

Similarly, the various EU directives that mandate substance bans have initiated wide scale research and development of alternative materials. Lead is a case in point. Lead has been widely used in the electronic industry in solders. Lead-free solders have existed for many years but it was the mandate in the Restriction of use of certain Flazardous Substances Directive (RoHS) to have products free of lead by July 2006 that spurred industry research, planning and adoption of the substitutes. Annex I lists examples of Green Chemistry case studies where research was stimulated in response to legislation targeting hazardous materials. 

In the 13 case studies documented processes and experiences of attempts to substitute hazardous substances in the 1980s and 1990s were examined. The aim of the choice of cases was to cover a wide spectrum of substitution conditions consumer-close and consumer-remote products, product auxiliary materials and process auxiliary materials, SMEs and large-scale industiy, environment, consumer and occupational health and safety subjects, technical and organisational iimova-tions. 

Industrially relevant consecutive-competitive reaction schemes on metal catalysts were considered hydrogenation of citral, xylose and lactose. The first case study is relevant for perfumery industry, while the latter ones are used for the production of sweeteners. The catalysts deactivate during the process. The yields of the desired products are steered by mass transfer conditions and the concentration fronts move inside the particles due to catalyst deactivation. The reaction-deactivation-diffusion model was solved and the model was used to predict the behaviours of semi-batch reactors. Depending on the hydrogen concentration level on the catalyst surface, the product distribution can be steered towards isomerization or hydrogenation products. The tool developed in this work can be used for simulation and optimization of stirred tanks in laboratory and industrial scale. 

The following case study illustrates how a product is scaled-up from 15 to 150 kg in equipment supplied by Niro pharma systems once one understands the critical process parameters used when scaling-up. 

This case study will summarize the development of a pan-coating process designed for the application of an enteric coating to a tablet product, provide insight into some of the early process optimization studies that were undertaken, and show how these ultimately facilitated the development of production-scale manufacturing processes. 

Effective product and process optimization play a prominent role in any successful scale-up study. As an illustration, this case study summarizes the initial development, and subsequent scale-up, of a Wurster process designed to facilitate the application of an aqueous ethylcellulose dispersion to drug-loaded pellets. At the same time, it was intended to deal, up front, with some of the idiosyncrasies of such a coating system that often influence the functionality of the final dosage form. 

Hamende, M. (2005) Case study in production-scale mulhcolumn continuous chromatography, in Preparative Enantioselective Chromatography, 1st edn (ed. G. Cox), Wiley-Blackwell, Hoboken NJ, p. 253. 

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