Hydrogen sulphide vapour pressure

Figure 9.5 Hydrogen sulphide vapour pressure vs temperature...

Hydrogen sulphide oeeurs naturally, e.g. in natural gas and petroleum, voleanie gases, and from deeaying organie matter. It may be present near oil wells and where petroleum is proeessed. Commereially it is obtained as a by-produet from many ehemieal reaetions ineluding off-gas in the produetion of some synthetie polymers (e.g. rayon, nylon) from petroleum produets, and by the aetion of dilute mineral aeids on metal sulphides. Physieal properties are summarized in Table 9.14 and effeets of temperature on vapour pressure are shown in Figure 9.5. 

Hydrogen sulphide is used in the preparation of metal sulphides, oil additives etc., in the purification and separation of metals, as an analytical reagent and as raw material in organic synthesis. Physical properties are summarized in Table 8.11 and effects of temperature on vapour pressure are shown in Figure 8.4. 

A mixture of ammonia and hydrogen sulphide does not unite if the press, is less than a certain critical value, which depends on the temp. If the press, is at or above this value crystals of ammonium hydrosulphide are formed if the press, be increased,more crystals will form and if the press, be reduced, crystals will decompose. When the two gases are present in eq. amounts this press, is called the dissociation pressure of the solid. In the present case, if the vapour phase has the same composition as the solid with which it is in equilibrium, the system is univariant, and there is a definite dissociation press, for each temp. F. Isambert found the dissociation press, of ammonium hydrosulphide, in mm. of mercury, increases rapidly with a rise of tomp. ... 

Liquid hydrogen sulphide is a colourless, very mobile fluid, which resembles the dry gas in being neutral to litmus.3 Its vapour pressure increases rapidly with rise of temperature, finally attaining a critical pressure of 88-9 atmospheres at the critical temperature, 100 4.° C.4... 

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). 

The vapour pressure and density affect the substances rate of reaction (the amount and rate of atoms/molecules escaping) and where/what level the gas will be found (hydrogen sulphide heavier than air, methane lighter than air). This information will enable a variety of differing control measures to be considered. 

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