(77d) Process Intensification; Challenge, Targets and Experience

In teaching chemical engineering the Eastman Kodak process serves as a welcome demonstration for process intensification in methyl acetate synthesis. History and development of this specific process features several aspects of process intensify-cation in chemical engineering, covering the technology, process design, hydraulics as well as economics. Although dating back to the eighties this process is still a benchmark, worth matching with, in particular and in general.  Beside facing the challenge of direct process related competition we may also draw valuable conclu-sions for future guidelines in new fields of applications from the history, the design strategy and the outcome of this demonstration example.

Do we identify any future applications in the pipeline? When talking about future applications, these challenges have already emerged on a selfenhancing and selfaccelerating global scale. Following the recommendations of several biorefinery roadmaps we expect from biorefinery a span of contributions and new technologies to several aspects of energy management, product and process development as well as sustainable effects on a safer environment. And, we may address the complete toolbox of process intensification. The basic question is how to get process intensification in biorefinery technologies started and successfully applied? By identifying thermodynamic limits and technological obstacles, the specification of process needs as well as product related needs is an approach we may simply base project initiation on, since we talk about multi feedstock multiproduct mixtures with complex interactions due to the nature and chemistry of substances.

The synthesis of methyl acetate is a welcome basic project. Synthesis of methyl acetate is limited by the chemical equilibrium, azeotropic product mixtures as well as low relative volatility of binary systems. The basic industrial scale Eastman Kodak process with successful application of process intensification, has been mentioned. Does it therefore leave any driving force for further intensification activities? It does, since implementation of pervaporation offers an alternative technological approach for synthesis and separation and product isolation.

Separation of azeotropic mixtures is a very representative example for applying the process intensification toolbox in biorefinery. Exemplarily the distillation of formic acid/acetic acid/water-mixtures, frequently formed in biomass processing,  is more or less impossible, since we are faced with a saddle azeotrope. Reactive separations give access to a variety of process concepts which help overcome the thermodynamic limits of separation.

When addressing separations in biorefinery applications, liquid/liquid-extraction processes may suffer from third phase formation and emulsification. Measures in design and construction may help overcome operation limits.

Application of process intensification tools in development and design of future biofuel production is a high priority task and must, if we expect biofuels to contribute significantly to fueling traffic and industry in future, be trementously intensified. Seemingly the transfer of Fischer-Tropsch technology from coal conversion to application in biomass conversion is expected to serve as state of the art technology, but overall process efficiency and yield limitation strongly recommend intensified investigation of alternative routes to finally obtain fuels with sufficient calorific value and stability at an acceptable oxygen level originating in the feed. 

With this practical experience in mind the discussion of rules, strategies and recommendations in process development, design and intensification is a welcome opportunity to check the content of the toolbox and the effectiveness of tools.