Reactor design, commercial processing

The feature that is most usefiil in distinguishing commercial methanol processes from one another is the type of reactor used. The four basic types in use ate shown in Figure 7. There are a variety of proprietary reactor designs commercially available from Hcensors, all of which are either one of these four types or a combination of two among them (17—22). 

Company Dates of Involvement in SCWO Commercialization Unique Reactor Design or Process Feature Licensees or Partners... 

This volume contains most of the papers presented at the symposium. In addition, several chapters written by leading experts in the field have also been included. Several important aspects of immobilized microbial cell technology are discussed here carriers for immobilization, methods of cell attachment, biophysical and biochemical properties, reactor design, and process engineering of bound cell systems. A number of applications in the food, pharmaceutical, and medical areas— including those commercialized already— have been described. In essence, this is a comprehensive single volume state-of-the-art presentation of immobilized microbial cell systems. 

Recent advances in Eischer-Tropsch technology at Sasol include the demonstration of the slurry-bed Eischer-Tropsch process and the new generation Sasol Advanced Synthol (SAS) Reactor, which is a classical fluidized-bed reactor design. The slurry-bed reactor is considered a superior alternative to the Arge tubular fixed-bed reactor. Commercial implementation of a slurry-bed design requires development of efficient catalyst separation techniques. Sasol has developed proprietary technology that provides satisfactory separation of wax and soHd catalyst, and a commercial-scale reactor is being commissioned in the first half of 1993. 

The ammonolysis of phenol (61—65) is a commercial process in Japan. Aristech Chemical Corporation (formerly USS Chemical Division of USX Corporation) currently operates a plant at Ha verb ill, Ohio to convert phenol to aniline. The plant s design is based on Halcon s process (66). In this process, phenol is vapori2ed, mixed with fresh and recycled ammonia, and fed to a reactor that contains a proprietary Lewis acid catalyst. The gas leaving the reactor is fed to a distillation column to recover ammonia overhead for recycle. Aniline, water, phenol, and a small quantity of by-product dipbenylamines are recovered from the bottom of the column and sent to the drying column, where water is removed. 

This monomer is ethylene when R is hydrogen, propylene when R is a methyl group, styrene when R is a benzene ring, and vinyl chloride when R is chlorine. The polymers formed from these four monomers account for the majority of all commercial plastics. The polymers come in great variety and are made by many different processes. All of the polymerizations share a characteristic that is extremely important from the viewpoint of reactor design. They are so energetic that control of the reaction exotherm is a key factor in all designs. 

Collect together all the kinetic and thermodynamic data on the desired reaction and the side reactions. It is unlikely that much useful information will be gleaned from a literature search, as little is published in the open literature on commercially attractive processes. The kinetic data required for reactor design will normally be obtained from laboratory and pilot plant studies. Values will be needed for the rate of reaction over a range of operating conditions pressure, temperature, flow-rate and catalyst concentration. The design of experimental reactors and scale-up is discussed by Rase (1977). 

One of the most important advantages of the bio-based processes is operation under mild conditions however, this also poses a problem for its integration into conventional refining processes. Another issue is raised by the water solubility of the biocatalysts and the biocatalyst miscibility in oil. The development of new reactor designs, product or by-product recovery schemes and oil-water separation systems is, therefore, quite important in enabling commercialization. Emulsification is thus a necessary step in the process however, it should be noted that highly emulsified oil can pose significant downstream separation problems. 

These components of scale-up manifest themselves through the effects of chemical kinetics, mass transfer, and heat transfer. As an example of the way these factors interrelate to scale-up, the general process of commercial scale reactor design is shown inFigure 3.19, which is similar to presentations in [204, 205]. 

The other major issue in reactor design concerns catalyst deactivation and membrane fouling. Both contribute to loss of reactor productivity. Development of commercially viable processes using inorganic membrane reactors will only be possible if such barriers are overcome. These subjects will receive greater attention as current R D efforts expand beyond laboratory scale evaluations into field demonstrations. 

The oxyhydrochlorination process can utilize either a fluid bed, a fixed bed, or fluid and fixed beds in series. Published economic data (3) indicate that these various reactor designs offer potentially the same economic returns however, the fluid bed system has been the most successful in commercial operation because of the following ... 

Figure S.4. Residence time distributions of pilot and commercial catalyst packed reactors CWalas, Chemical Process EQuipment Selection and Design, 19903.

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