Mixing energy efficiency

Abstract Sonochemical synthesis, an energy efficient processing technique to induce a variety of physical and chemical transformations is on the rise. A variety of simple and mixed metal oxides and sulfides have been obtained using this technique. The present chapter reviews the types of oxides and sulfides obtained in the last few years. 

MTBE is a well known enhancer of the number of octanes in gasoline and as excellent oxygentated fuel additives that decrease carbon monoxide emissions. Therefore, MTBE has been one of the fastest growing chemicals of the past decade. MTBE is produced by reacting methanol with isobutylene from mixed-C4 stream liquid phase over a strong acid ion-exchange resin as catalyst. An excess of methanol is used in order to improve the reaction conversion. This excess has to be separated from the final product. The pervaporation technique, more energy efficient and with lower cost process, has been proposed as alternative to distillation [74],... 

Krishnan Sankaranarayanan received his MSc at Delft University of Technology, the Netherlands and his PhD at Princeton University, New Jersey. At Delft, he did an extensive study of the energy efficiency of the polyolefin industry, for which activity DSM acted as host. He is currently group head reactor engineering and mixing at ExxonMobil Research and Engineering, Fairfax, Virginia. 

The purity of the generated hydrogen is 98 9 per cent, and that of the oxygen 97 per cent. On an average the consumption of energy is 417 KW.H. per cubic metre of mixed gases, and a current output of 96 per cent, is attained with an energy efficiency of 57 per cent. 

The optimum stirrer, from the point of view of energy efficiency, is the one that requires the least power at the critical speed of rotation. In terms of a dimensionless relation, this can be expressed as the condition where Ne Fr3/jj is minimum. For a propeller stirrer with Ne = 0.50 and a turbine stirrer with Ne = 10.0, and with the values of b already given for the two stirrers, the propeller stirrer requires only 20% of the power needed by the turbine stirrer. Mixing Equipment Co, CA, has recently introduced a new impeller design that consists of a pitched blade turbine (three blades). At the tips of the... 

When the catalyst is available in a small amount, a microreactor assembly is often used (Miller, 1987). This is a simple T-type reactor heated by a fluidized sand bath. The mixing is provided by mechanical agitation that shakes the reactor up and down within the fluidized bed. Because of the small amount of slurry, and an effective heat transfer in the fluidized sand bath, the heat-up period in such a reactor is small. The nature of mechanical agitation is, however, energy-efficient. The reactor provides only a small sample for the product analysis, which makes the usefulness of the reactor for detailed kinetic measurements somewhat limited. The reactor has been extensively used for laboratory catalyst screening tests in coal liquefaction. 

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