THERMODYNAMIC ANALYSIS OF H2 – O2 – C SYSTEM
DOI:
https://doi.org/10.14529/met180401Keywords:
hydrogen, oxygen, carbon, hydrogen аnd carbon oxides, gas, dissociation of water vapour and carbon dioxide, oxygen potential, carbon blackAbstract
In a heterogeneous mixture of (H2 – O2 – C) at elevated temperatures as a result of oxidation reactions, reaction of water gas and two reactions of carbon gasification a gas mixtures (H2 – H2O – CO – CO2) is formed. In work thermodynamic analysis of possible processes is perform, going at temperatures of 700 –1500 K in the system (H2 – O2 – C). The equilibrium parameters a gas mixtures (compositions and oxidation – reduce innovative properties) are determined.
In any gas mixture containing H2O and (or) CO2, a very low concentration of oxygen formed as a result of the dissociation of H2O and CO2 is usually determined by the value of lg(pO2 , atm). At a given total pressure, this value is calculated from the composition of the gas mixture and reference information for H2O or CO2 dissociation reactions. The results of the analysis are represented by two nomograms. First, such nomograms are illustrative, alternative tabular, way of presenting a very extensive information on the properties of complex gas mixtures. Second, using nomograms and reference information on equilibrium pressure of dissociation of metal oxides it is possible to estimate parameters of reduce of these oxides.
In binary gas mixtures (CO – CO2) and water gas (H2 – H2O – CO – CO2) in certain combinations of composition and temperatures may form carbon black. By that the existence of restrictions at temperatures below ~ 1100 K in production of water gas with any concentration components.
Various technological and economic options are available of the appropriate of the methods of producing gas mixtures. In particular, when heated water vapor in contact with are overweight of carbon up to ~ 1100 K can be obtained practically clean equimolar mixture (H2 – CO) with high reduction potential. Introduction to this system of hydrogen allows the gas mixture with any information arbitrarily low pressure of oxygen, and this makes thermodynamically possible reduce of oxide of any metal.
The expediency of representation is analyzed three-dimensional diagram, built on concentration triangle “H2 – O2 – C”. Reaction accounting methane formation leads to noticeable changes in the gas mixture parameters only at temperatures below about 900 K.
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