Problem 1. Prediction of the Viscosity of an Andrussow Process Feed Gas
Mixture at Low Density. (30 points)
In the Andrussow process for the manufacture of HCN, methane, ammonia, and air
are blended from separate feedstock sources at 100°C to create a target composition.
The resulting gas mixture is then introduced into a reactor where it is rapidly heated
and then passes through a noble metal gauze catalyst at 1100°C using contact times
on the order to 10 to 100 milliseconds. For this illustration, assume that the feed
composition 15 vol% methane, 20 vol% NH$_4$, and the balance is bone-dry air.
Answer the following questions.
(a) Write a balanced chemical equation that describes the overall reaction for the
HCN synthesis.
(b) Create an Excel or Matlab table that shows the viscosity of both the pure
components in the feed mixture and the gas mixture (g/cm-s) over the above
temperature range using an increment of 50°C. Also, plot the viscosity as a
function of temperature (in K). Is there an empirical equation form that leads
to a linear or near-linear representation of the model predictions?
In part b, first evaluate the viscosity of the mixed gas at the given composition
and at 100°C by manual calculations. Next, create an Excel or Matlab code
that performs these calculations for this condition and the others. Be sure and
show all parameters and equations used to support the manual results.
What can you say about the gas mixture behavior over this temperature range?
