Chemical Process

Nuclear fusion is a type of nuclear reaction in which to atomic nuclei combine to form a heavier nucleus, releasing energy. For a fusion reaction to take place, the nuclei, which are positively charged, must have enough kinetic energy to overcome their electrostatic force of repulsion. This can occur either when one nucleus is accelerated to high energies by an accelerating device or when the energies of both nuclei are raised by the application of very high temperatures. The later method, referred to as thermonuclear fusion, is the source of Sun’s energy, if a proton is accelerated and collides with another proton, these nuclei can fuse, forming a deuterium nucleus (one proton and one neutron), a positron, a neutrino, and energy. Such a reaction is not self sustaining, because the released energy is not readily imparted to other nuclei. Thermonuclear fusion of deuterium and tritium (one proton and two neutrons) will produce a helium nucleus and an energetic neutron that can help sust...

 An industrial chemical reactor is a complex device in which heat transfer , mass transfer, diffusion, and friction may occur along with chemical reaction, and it must be safe and controllable. In large vessels, questions of mixing of reactants, flow distribution, residence time distribution, and efficient utilization of the surface of porous catalysts also arise. A particular process can be dominated by one of these factors or by several of them; for example, a reactor may on occasion be predominantly a heat exchanger or a mass-transfer device. A successful commercial unit is an economic balance of all these factors. Many successful types of reactors are illustrated throughout this section. Additional sketches may be found in other books on this topic, particularly in Walas (Chemical Process Equipment Selection and Design, Butter worths, 1990) and Ullmann (Encyclopedia of Chemical Technology (in German), vol. 3, Verlag Chemie, 1973, pp. 321–518). The general characteristics ...