chemical physics of discharges - Argonne National Laboratory

Table 3.- Product Gas Analyses and Yields of Hydrogen Cyanide from
Tests with hvab Coal. Ammonia, and Air at 1,250" C
Product gas, percent Length Feed
of run, N&, Air, Coal,
Test HC&' C& NH3 H2 N2 CO min cu ft/hr du ft/hr lb/hr
C-123 10.3 1.1 10.2 62.8 16.2 9.7 20 5.90 0.52 0.17-0.20
C-124 10.9 0.6 6.9 62.1 17.2 13.2 20 2.96 .53 .17- .20
C-125 9.2 .4 9.6 48.4 31.5 10.1 20 3.08 1.08 .17- .20
Total Yield, cu ft
. off gas, HCN/cu ft HCN/cu ft N&
cu ft/hr HCN/lb coal NKq feed c on s ume d
C-123 4.18 2.30 0.073 0.078
C-124 3.05 1.77 .112 .120
C-125 3.70 1.82 .110 .123
- 1/ Wet-analytical method of analysis for HCN only; other components are the
average of 2 chromatograph and 2 mass spectrometer analyses, HCN-free basis.
Tests With Methane and Ammonia
Tests were made without coal feed %ut with amnonia and methane to determine
the resulting hydrogen cyanide yields for comparison. In one series of tests
2.0 cu ft/hr of methane was reacted with ammonia in flows varying from 0.3 to
2.5 cu ft/hr at 1,250' C. As illustrated in figure 4, yields of 0.18 to 0.61
cu ft of hydrogen cyanide per cubic foot of ammonia consumed were obtained,
equivalent to 1.2 to 13.8 percent hydrogen cyanide in the product gas. The
yield of hydrogen cyanide reached a maximum at a feed ratio of methane to amonia
of about 1 to 1.
' A series of tests was made in which the methane and ammonia flow rates
were maintained at 2 and 1 cu ft/hr, respectively, while the reactor temperature
was increased from l,OOOo to 1,275' C. Hydrogen cyanide yields are plotted
with temperature in figure 5, indicating increased hydrogen cyanide yields with
increased temperature. Maximum yields of about 0.6 cu ft of hydrogen cyanide
per cubic foot of ammonia consumed were obtained at the higher temperatures,
while at 1,000" C only 0.07 cu ft of hydrogen cyanide per cubic foot of amnonia
consumed was formed.
To explore the use of coal-derived gases in the formation of hydrogen
cyanide from amnonia, synthetic mixtures of a low-temperature carbonization
gas, a coke oven gas, and a producer gas were prepared and reacted with amnonia
at 1.250" C. Gas flows were adjusted to give a minimum methane-to-ammonia
ratio of 1 to 1. In figure 6 the hydrogen cyanide yields obtained are plotted
with the methane' contents of the coal gases. Increasing hydrogen cyanide yields
were produced with increasing methane contents of the feed gas.
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