Thermodynamics carbon monoxide hydrogenation

J. Hilsenrath, et al., Tables of Thermal Properties of Gases, NBS Circ. No. 564 (1955), reprinted as Tables of Thermodynamic and Transport Properties of Air, Argon, Carbon Dioxide, Carbon Monoxide, Hydrogen, Nitrogen, Oxygen and Steam, Pergamon Press, Oxford (1960). 

Tables of Thermal Properties of Gases , by Hilsenrath et include the thermodynamic properties of air, argon, carbon dioxide, carbon monoxide, hydrogen, nitrogen, oxygen, and steam. 

The composition of the products of reactions involving intermediates formed by metaHation depends on whether the measured composition results from kinetic control or from thermodynamic control. Thus the addition of diborane to 2-butene initially yields tri-j iAbutylboraneTri-j -butylborane. If heated and allowed to react further, this product isomerizes about 93% to the tributylborane, the product initially obtained from 1-butene (15). Similar effects are observed during hydroformylation reactions however, interpretation is more compHcated because the relative rates of isomerization and of carbonylation of the reaction intermediate depend on temperature and on hydrogen and carbon monoxide pressures (16). 

The oxidation reactions of hydrogen, carbon monoxide, and hydrocarbons in the temperature range of 500 to 1500°F, where the catalytic reactors can be expected to operate, are all favored thermodynamically to... 

MRG [Methane rich gas] A catalytic steam-reforming system, similar to the classic syngas reaction of steam with a hydrocarbon mixture, but yielding hydrogen, methane, and carbon monoxide in different proportions. The system is thermodynamically balanced,... 

The hydrogen producing reactions are limited by thermodynamic equilibrium. The reactions must take place under carefully controlled external firing, with heat transfer taking place from the combustion gas in the firebox to the process gas in the catalyst-filled tubes. Carbon monoxide in the product gas is converted almost completely to hydrogen in the downstream catalytic reactor. 

Thermodynamic data will be used to calculate AH as a function of temperature between 298 and 1000 K. AG and K will then be calculated over the same temperature range. Finally, the equilibrium composition of a stoichiometric mixture of carbon monoxide and hydrogen at a temperature of 600 K and a pressure of 300 atm will be obtained. 

At temperatures between 900° and 2000°K. most hydrocarbons have a positive free energy of formation which, with the exception of acetylene, increases with increasing temperature (Figure 1). If coal carbonization could attain thermodynamic equilibrium over this temperature range, the hydrocarbon by-products would be decomposed mainly to carbon and hydrogen while any oxygen in the coal would be evolved as carbon monoxide. In... 

Does methanol have a thermodynamic tendency to decompose into carbon monoxide and hydrogen at 25°C Would the tendency be stronger at a higher or a lower temperature ... 

The thermodynamics of the above reactions are illustrated in Figures 5.6 and 5.7174. Both figures assume a steam-to-methane ratio of 1.0. Figure 5.6 illustrates how the feed and product gases interact when the product gas has a hydrogen-to-carbon monoxide ratio of 3.0. Figure 5.7 illustrates the effects of temperature and pressure on the reactions. As pressure increases, lower conversion can be expected and more methane will not be converted and will be found in the reformer discharge stream. 

The reactants, coal, water and oxygen are converted to hydrogen, carbon monoxide, carbon dioxide, methane, water vapour and hydrogen sulphide at a given temperature and pressure according to thermodynamic equilibria and the kinetics of gasification. A particular coal composition which is characteristic of a German hard coal was taken as a basis (Table I). 

Thermodynamically the insertion of an alkene into a metal-hydride bond is much more favourable than the insertion of carbon monoxide into a metal-methyl bond. The latter reaction is more or less thermoneutral and the equilibrium constant is near unity under standard conditions. The metal-hydride bond is stronger than a metal-carbon bond and the insertion of carbon monoxide into a metal hydride is thermodynamically most often uphill. Insertion of alkenes is also a reversible process, but slightly more favourable than CO insertion. Formation of new CT bonds at the cost of the loss of the ji bond of the alkene during alkene hydrogenation etc., makes the overall processes of alkenes thermodynamically exothermic, especially for early transition metals. 

The skills developed to produce the equilibrium diagram Figure A.l, are now applied anew. Neither hydrogen nor carbon monoxide occur as free substances in nature, where they are immediately oxidized. They must be made and stored, at thermodynamic and economic cost. The reversible thermodynamics are assessed below, using as the basis of calculation a notional, electrochemical, equilibrium, steam reformer. Figure A.4, for comparison with the alternative practical and irreversible combustion-driven reformers. 

The equilibrium thermodynamics of a hydrogen fuel cell are further compared with those of a carbon monoxide fuel cell. At equilibrium both cells can be described as having a high vacuum of reactants and a high concentration of products. 

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