Exothermic process Describes processes that

Exothermic Describes processes that release heat energy. 

Exothermic (Section 1.2) Term describing a reaction or process that gives off heat. 

The amount of ammonia formed in a single pass of the synthesis gas over the catalyst is much too small to be of interest for an economic production. Haber therefore recycled the unconverted synthesis gas. After separating the ammonia by condensation under synthesis pressure and supplementing with fresh synthesis gas to make up for the portion converted to ammonia, the gas was recirculated by means of a circulation compressor to the catalyst-containing reactor. This process, described in the patent DRP 235 421 (1908), became the basis for the industrial manufacture of ammonia and since then the same principle has found widespread application in numerous high-pressure processes. Haber also anticipated the preheating of the synthesis gas to reaction temperature (at that time 600 °C) by heat exchange with the hot exhaust gas from the reactor, the temperature of which would be raised by the exothermic ammonia formation reaction sufficiently (about 18 °C temperature rise for a 1 % increase of the ammonia concentration in converted synthesis gas). 

As the technology for piping gas from the source began to improve, it became possible to pipe natural gas over thousands of miles. This has meant that natural gas has become as convenient as petroleum and coal to use as a fuel source, and often with far less pollution. Natural gas bums with almost no byproducts except for carbon dioxide and water (as opposed to coal which often has large amounts of sulfur in it), and the heat released from the reaction (combustion of any of the hydrocarbon components of natural gas is an exothermic process). The combustion of methane, the most prevalent component of natural gas, is described by the reaction below ... 

The process described by eq (3) actually means a decomposition of the acid reflected in the DTA curve by the exothermic peak without any mass loss as indicated by TG, in accordance with the stoichiometry of the oxide formation. A recent UHV-TG study of unsupported 12-tungstosilicic acid with respect to the process of water loss during activation revealed that already at about 432 K water is removed to an extent of approximately 76% [12]. DTA/TG measurements of supported 12-tungstosilicic acid (sample lOW-ZSM-5) could not resolve... 

The anharmonic model for parallel reactions can be extended to the study of parallel exothermic and endothermic reactions. For the sake of simplicity, we shall assume that the energy levels are evenly spaced, i.e., harmonic. For example, consider the model described in Fig. 7, where the zero energy of product B is level 7, which is lower than the zero energy of the reactant by an amount of 2kT. The reaction from reactant R to product B is an exothermic process. Conversely, the reaction from R to product C, which has its energy of zero at level 9, is an endothermic reaction. Various models of exothermic and endothermic reactions have been investigated. Results are shown in... 

In all these cases it appears that the exothermic process must be initiated by heating the preformed pellets, etc. in a furnace. This is again the above-described high-temperature process in which the need for promoting reactivity by an initial high temperature derives either from the dilution of the reactants with oxides, the low heat output of the main reaction, or both. 

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