PLP $10$: $($Problem $5$ in sample exam$)$ Due on Feb $7^{th}.$

Most modern processes for production of nitric acid are based on the sequential oxidation of ammonia to oxides of nitrogen followed by absorption of these intermediates in water. In the flowsheet shown in Figure ammonia and air are mixed in a $1$:$10$ molar ratio and reacted catalytically in the first reactor stage. The two reactions occurring are the main reaction

$4N{H}_3+5O_{2}4NO+6H_{2}O$

and the secondary reaction

$2N{H}_3+\frac{3}{2}{O}_2{N}_2+3H_{2}O$

All of the $N{H}_3$ is converted with a $95\%$ selectivity for $NO.$ In the second reactor stage, the $NO$ produced is further oxidized to $N{O}_2$ via the reaction

$NO+\frac{1}{2}{O}_{2}N{O}_2$

Finally, the reactor $2$ effluent is further treated with water to produce the desired $60\%HN{O}_3$ product. The scrubber reaction is

$2N{O}_2+\frac{1}{2}{O}_2+H_{2}O2HN{O}_3$

The waste gas from the process contains $\frac{1}{2}\%N{O}_2$ and about $10\%H_{2}O.$ The air composition may be taken as $21\%O_2$ and $79\%N_2.$ Assuming all compositions are in mol$\%,$ calculate the composition of all streams in the process.

Overall Process

No$.$ Unknown Labeled variables $\{$

$+,$ No$.$ Independent chemical reactions $($one extent of reaction for each$)$

$,$ No$.$ Independent reactive species balances $\{$

No$.$ Independent nonreactive species $\{$

No$.$ Known relations $\{\}$

$=$ No$.$ Degrees of frEedom

Reactor $1$

No$.$ Unknown Labeled variables $\{\}$

No$.$ Independent chemical reactions $($one extent of reaction for each$)$

No$.$ Independent reactive species balances $\{$

No$.$ Independent nonreactive species $\{$

No$.$ Known relations $\{\}$

$=$ No$.$ Degrees of freedom

Reactor $2$

No$.$ Unknown Labeled variables $\{$

$\}$

$+,$ No$.$ Independent chemical reactions $($one extent of reaction for each$)$

No$.$ Independent reactive species balances $\{$

No$.$ Independent nonreactive species $\{$

$,$ No$.$ Known relations $\{\}$

$\}$

$\}$

$\}$

$\}$

$=$ No$.$ Degrees of freedom

PLP $10$: $($Problem $5$ in sample exam$)$ Due on Feb $7^{th}.$

Most modern processes for production of nitric acid are based on the sequential oxidation of ammonia to oxides of nitrogen followed by absorption of these intermediates in water. In the flowsheet shown in Figure ammonia and air are mixed in a $1$:$10$ molar ratio and reacted catalytically in the first reactor stage. The two reactions occurring are the main reaction

$4N{H}_3+5O_{2}4NO+6H_{2}O$

and the secondary reaction

$2N{H}_3+\frac{3}{2}{O}_2{N}_2+3H_{2}O$

All of the $N{H}_3$ is converted with a $95\%$ selectivity for NO$.$ In the second reactor stage, the $NO$ produced is further oxidized to $N{O}_2$ via the reaction

$NO+\frac{1}{2}{O}_{2}N{O}_2$

Finally, the reactor $2$ effluent is further treated with water to produce the desired $60\%HN{O}_3$ product. The scrubber reaction is

$2N{O}_2+\frac{1}{2}{O}_2+H_{2}O2HN{O}_3$

The waste gas from the process contains $\frac{1}{2}\%N{O}_2$ and about $10\%H_{2}O.$ The air composition may be taken as $21\%O_2$ and $79\%N_2.$ Assuming all compositions are in mol$\%,$ calculate the composition of all streams in the process.