13.2.6 $SO_2$ and $H{_2}S$ Production from Coal

For coal, it is assumed that sulfur is distributed between the volatiles and the char. Since there is no reason to assume that S is equally distributed between the volatiles and the char, the fraction of S in the volatiles and the char should be specified separately.

$SO_2$ and $H{_2}S$ from Char

The source of $SO_2$ and $H{_2}S$ from the char is related to the rate of char combustion:

$$S_{\rm char, i} = \frac{S_{c} \; Y_{\rm S, char} M_{w,{\rm i}}}{M_{w,{\rm S}} V}$$ (13.2-10)

where	$S_{c}$	=	char burnout rate (kg/s)
	$S_{\rm char, i}$	=	source of $i$ (kg/m $^3$-s) in char, where $i = SO_2$ or $H{_2}S$
	$Y_{\rm S, char}$	=	mass fraction of sulfur in char
	$V$	=	cell volume (m $^{3}$)

$SO_2$ and $H{_2}S$ from Volatiles

The source of $SO_2$ and $H{_2}S$ from the volatiles is related to the rate of volatile release:

$$S_{\rm vol, i} = \frac{S_{\rm vol} \; Y_{\rm S, vol} M_{w,{\rm i}}}{M_{w,{\rm S}} V}$$ (13.2-11)

where	$S_{\rm vol, i}$	=	source of volatiles originating from
			the coal particles into the gas phase (kg/s), where $i = SO_2$ or $H{_2}S$
	$Y_{\rm S, vol}$	=	mass fraction of sulfur in the volatiles
	$V$	=	cell volume (m $^{3}$)