Chemical route energy efficiency

On the one hand, the current petrochemical route would continue to provide the world with the chemicals consumers require. To satisfy the need for a more sustainable development, the petrochemical industry would continue its drive toward a continuous improvement in energy efficiency (see Figure 10.3). This drive will primarily include the continuous improvement of the current crude-oil-based processes while stranded methane or CO2 would be utilized as complementary feedstock. 

Many older processes (developed before the 1970s oil price crisis) were less energy efficient than those developed more recently. This should be apparent by consideration of the energy conservation features included in new plants, and the subsequent increase in complexity of the associated P ID. Energy conservation is discussed in Section 8.2.1. The selection of a process route for production of a chemical will depend upon the following factors/considerations ... 

Highly efficient chemistries that unite biological and chemical transformations as part of synthetic route design Artificial inteUigence-enabled synthetic route design Development and implementation of mass and energy efficient reactions... 

Catalysis enhances the sustainability of today s world. Raw material utilization, energy efficiency, elimination of hazardous synthesis routes, pollution abatement and so on are a few examples of issues that are typically addressed by catalysis and, hence, contribute to safer, cleaner, more reliable, and more economical chemical processes (1). Catalyst development and improvement require an elaborate testing of candidate catalytic materials. Not only the physical properties, such as porosity, crystallinity, and surface composition are investigated but also and even more importantly, the functional properties such as the kinetics need to be determined. The observed kinetics is constituted by a sequence of different steps. When investigating a reaction mechanism in detail, operating conditions are selected at which the physical transport phenomena are not rate limiting. At such operating conditions, the observed kinetics are entirely determined by the chemical adsorption and reaction phenomena and, hence, they correspond to so-called intrinsic kinetics (2). 

Mitsubishi Rayon produces acrylamide from acrylonitrile with the help of an immobilized bacterial enzyme, nitrile hydratase (see Fig. 9.20). This acrylamide is then polymerized to the conventional plastic polyacrylamide. This process was one of the first large-scale applications of enzymes in the bulk chemical industry and replaced the conventional process that used sulfuric acid and inorganic catalysts. The enzymatic process has several advantages over the chemical process. The efficiency of the enzymatic process is 100%, while that of the previous chemical process was only 30-45%. The energy consumption is only 0.4MJ/kg product, compared to 1.9MJ/kg product for the chemical route. The process generates less waste. The CO2 production is only 0.3 kg/kg monomer, while the previous process produced 1.5 kg/kg. The reaction is carried out at 15°C, which is milder than the original chemical route. About 100,000 tons of acrylamide are produced yearly now via this approach in Japan and other countries. 

H2 separation technologies are of great importance due to the role of H2 as an alternative, clean, energy-efficient carrier. Membrane related processes are considered to be one of the most promising routes in the production of high purity H2. Pd membranes are well known for their application in H2 separation and purification due to their high chemical permeability and perfect selectivity to hydrogen [1]. 

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