Intensification sustainability

Innovation is the key issue in today s chemical process industries. The main directions are sustainability and process intensification. Sustainability means in the first place the efficient use of raw materials and energy close to the theoretical yields. By process intensification the size of process plants is considerably reduced. The integration of several tasks in the same unit, as in reactive separations, can considerably simplify the flowsheet and decrease both capital and operation costs. 

Groen, D.J., Noorman, H.J., and Stankiewicz, A. (2005) Improved method for aerobic fermentation intensification, in Proceedings of the International Conference Sustainable (Bio)Chemical Process Technology,... 

Epitaxial effects are not limited to single-crystalline substrates. The possibility for substrate-induced epitaxial development in the difficult case of ZnSe (cf. conventional electrodeposition) has been established also by using strongly textured, albeit polycrystalline, zinc blende (111) CdSe electrolytic films to sustain monolithic growth of ZnSe in typical acidic selenite baths [16]. Investigation of the structural relations in this all-electrodeposited ZnSe/CdSe bilayer revealed that more than 30-fold intensification of the (111) ZnSe XRD orientation can be obtained on the textured (111) CdSe films, compared to polycrystalline metal substrates (Fig. 4.2). The inherent problems of deposition from the Se(IV) bath, i.e., formation of... 

Therefore, in this definition process intensification encompasses both novel apparatus and techniques which are designed to bring dramatic improvements in production and processing (Figure 1.8) [25]. As a result, safe, cheaper, compact, sustainable (environmentally friendly), and energy-efficient technologies are obtained. 

Dr Alexei Lapkin is a Senior Lecturer in Chemical Engineering at the University of Bath, UK, where he is also a Deputy Director of the Centre for Sustainable Chemical Technologies. He obtained his Master in Chemistry from the Novosibirsk State University, Russia, and Ph.D. in Chemical Engineering from the University of Bath. His research is focused on process intensification, bioprocessing, design and applications of functional materials. 

Tilman D, Balzer C, Hill J, Befort BL. Global food demand and the sustainable intensification of agriculture. P Natl Acad Sci USA.. 2011 108 20260-20264. DOI 10.1073/ pnas.1116437108... 

It should be pointed out that many biphasic systems have found their way into the chemical industry, starting from PTC and continuous flow (CF) processes. The reasons are that efficiency can be increased (rates, selectivity, energy requirements, reaction intensification), making them more economic and often more environmentally compatible, in short, more sustainable. 

The aroma compounds from the tropical fruits described in this chapter can be very important for consumers and industry as they are exotic and extremely pleasant however, the production of these compounds by biotechnological processes should be emphasised since the extraction from the fruits is a hard task. Many tropical soils contain less nitrogen and phosphorus, have lower capacity to absorb fertilisers, and therefore have lower conventional productive capacity, but some tropical soils have been very intensively farmed and further intensification is possible in other areas. Thus, the evaluation of a sustainable agriculture in tropical regions requires a sophisticated approach including the estimation of the risk of microbial or insect infestations. As many fruits go directly to fresh markets or to immediate processing, a continuing supply of the flavour manufacturers in the future is not completely assured. 

The philosophy of process intensification has been traditionally characterized by four words smaller, cheaper, safer, slicker. And indeed, equipment size, land use costs, and process safety are among the most important PI incentives. But process intensification can (and should) also be placed in a broader context—the context of sustainable technological development. Several years ago DSM published a picture symbolizing its own vision of process intensification (32), in which skyscraping distillation towers of the naphtha-cracking unit are replaced by a compact, clean, and tidy indoor plant (see Figure 3). The importance of PI for sustainable development and its role in the company s responsible business has been further stressed in a recent publication by the company s CEO, Peter Elverding (33). Here,... 

More and more chemical companies do recognize the fact that their image, their reputation, plays a very important role in successful business. A proper image of the company is necessary to ensure public support for its activities. A study done in the United States showed that only the tobacco industry and the nuclear energy sector had a worse reputation than the chemical industry. The situation in Europe is probably not very much different. On the other hand, process intensification, deeply anchored in the philosophy of sustainable development, in safe and environmentally friendly processing, presents perhaps the simplest, the most obvious key to the improved image of the chemical industry. 

This chapter is meant for developers and designers of processes, in particular of intensified processes, who want to ensure that their processes contribute to sustainable development. To this end problems with the present technological solutions in relation to the world-scale environment and society are explained in the first section. Then in the second section sustainable development is explained and the role and criteria for sustainable technology are derived. Finally process intensification is assessed on its contribution to sustainable development. 

The LCA results can be used for a sustainability assessment of a new technology by comparing the outcome with the existing technology results. In the conceptual phase of the new technology, a relative assessment can be used to highlight where improvements should be made and where the problem areas are. This is shown in Section 3 on process intensification assessment. 

THE POTENTIAL FOR PROCESS INTENSIFICATION TO CONTRIBUTE TO SUSTAINABLE DEVELOPMENT... 

Elaborate descriptions of process intensification will be found elsewhere in this book. Here a short description suffices, followed by an assessment on its potential to contribute to sustainable development, based on present industrial cases and general features. 

Process intensification consists of the development of novel apparatuses and techniques that, compared to those commonly used today, are expected to bring dramatic improvements in manufacturing and processing, substantially decreasing the ratio of equipment size to production capacity, energy consumption, or waste production and ultimately resulting in cheaper and more sustainable technologies (35). 

Table 7 contains a summary of the potential of process intensification for sustainable development. Some aspects will be explained in the sections that follow. 

Sustainable development item Process intensification improvement potential... 

Membranes and membrane processes are best suited in this context as their basic aspects well satisfy the requirements of process intensification for a sustainable industrial production. In fact, they are precise and flexible processing techniques, able to maximize phase contact, integrate conversion and separation processes, with improved efficiency and with significantly lower energy requirements compared to conventional techniques. 

The next important step in the elucidation of the role of the thermal factor in the mechanism of the phenomena in question was studying the effect of the sample size on the characteristics of the autowave process. Can the self-sustained wave regime of conversion be made impossible by intensification of heat release at the expense of a decrease in the diameter of a cylindrical sample containing the reactant mixtures By analogy with combustion physics, the question of a critical sample size has been raised. 

Finally, it is worth mentioning that a successful integration of catalytic reaction steps with product separation and catalyst recovery operations will also be dependent on innovative chemical reaction engineering. This will require the widespread application of sustainable engineering principles [48].In this context process intensification , which involves the design of novel reactors of increased volumetric productivity and selectivity with the aim of integrating different unit operations to reactor design, and miniaturization will play pivotal roles [49, 50]. 

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