Hydrogen sulfide occurrence

Characteristics of hydrogen sulfide, occurrence in petroleum industry, protection, and rescue procedures. 

Marttila et al. (1995) also examined the relationship between daily exposure to malodorous sulfur compounds (measured as total reduced sulfur [TRS]) from pulp production and experience of symptoms in a small population living in the vicinity of a pulp mill. The major components of the malodorous sulfur compounds are hydrogen sulfide, methyl mercaptan, and methyl sulfides. This work was initiated due to the observation that an unusually high short-term exposure to malodorous sulfur compounds (maximum 4-hour concentrations of hydrogen sulfide at 135 g/m3 [96 ppb]) led to a considerable increase in the occurrence of ocular, respiratory, and neuropsychological symptoms (Haahtela et al. 

The occurrence of hydrogen sulfide in the sewer atmosphere is an important example for illustrating odor problems and other negative effects associated with sulfide that will be further dealt with in Section 6.2.6. According to Table 4.1, HB2S = 563 atm (mole fraction)-1, and H2S, therefore, observes the... 

In addition to odor, several human health-related problems are potentially associated with the occurrence of hydrogen sulfide at concentration levels relevant for sewer networks. In this respect, it is interesting to compare values from Table 4.5 with Figure 4.2. The levels indicated in Table 4.5 depend on human sensitivity and time of exposure. 

Problems related to the occurrence of hydrogen sulfide have been intensively reported in the literature (cf. this chapter and Section 6.2.6). Although a great number of factors affect the relation between the occurrence and the problems identified, Table 4.6 can be considered a relevant approach. The table gives a simplified estimate, and indication of medium problems must not be considered equivalent to no need for control. ... 

Tne question of the source molecule occurrence must be addressed. The coincidence in anaerobic environments of ammonia and reduced divalent sulfur species, which includes hydrogen sulfide, bisulfide anion and sulfide dianion, has been given adequate recognition. (See for example references 36,37.) The coincidence of polysulfide and ammonia has already been noted in an earlier part of this report (1). Polysulfide has been found in tidal and salt marsh sediments as well (38). 

Interesting facets of this gas occurrence are that 1) it is limited to particular sections of the workings, and 2) in hydrogen sulfide-rich zones, this gas is scarcely detectable by odour until breakage of the coal. 

A pressure maximum, instead of minimum, inside the membrane could result from cases where both chemical reaction and surface diffusion are present [Sloot et al., 1992]. Thus the occurrence of a maximum or minimum local pressure inside the membrane depends on the reaction stoichiometry as well as the mobilities of the reaction species. It is assumed that only hydrogen sulfide adsorbs on the pore surface. Due to a higher transport rate of H2S enhanced by surface diffusion, the reaction zone is shifted toward the SO2 side of the membrane. In the reaction zone, larger amounts of the products are formed and higher molar fluxes of the products out of the membrane are expected so that the maxima of the mole fraction profiles of the products at the reaction zone can be sustained. 

Criteria are usually developed for particular populations and are generally based on prevention of an effect that occurs at lower doses ( critical effect ), which, if the levels do not exceed criteria, is expected to prevent the occurrence of more serious effects known to occur at higher doses. Criteria are available that are protective of acute, short-term, and chronic exposure for workers and the general public for hydrogen sulfide. Different agencies have developed exposure criteria and standards for hydrogen sulfide. Selected criteria and guidelines are provided below. 

Sulfur is a typical representative of the group of active outgassed elements. Sulfur dioxide (SO2) and hydrogen sulfide (H2S) are of common occurrence among the gaseous sulfur compounds evolved with volcanic gases. 

Ethanethiol. Ethyl mercaptan mercaptoethane ethyl sulfhydrate thioethyl alcohol. C,H,S mol wt 62.13. C 38.66%, H 9.74%, S 51,60%. CH2CH,SH. Found in urine of rabbits after ingestion of cabbage. Is formed in vinous fermentation. Occurs in illuminating gas, in sour" natural gas of W. Texas in petroleum distillates from which it may be separated hy chemical or physical methods Thompson et al. Anal Chem. 27, 175 (1955). Frepn from sodium ethyl -sulfate and KSH Klason, Ber. 20, 3407 (1887) catalytically From ethanol and hydrogen sulfide Kramer. Reid. J. Am. Chem. Soc. 43, 880 (1921). Review on occurrence, prepn, properties and reactions E. Emmet Reid. Organic Chemis-... 

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