Friday, March 02, 2007

HW #6, P13.34 - Multiple Reaction Equilibria and Their Dependence on T and P - 22 pts

"Synthesis gas" may be produced by the catalytic reforming of methane with steam :



The only other reaction considered is :



Assume equilibrium is attained for both reactions at 1 bar and 1300 K.

a.) Would it be better to carry out the reaction at pressures above 1 bar ?

b.) Would it be better to carry out the reaction at temperatures below 1300 K ?

c.) Estimate the molar ratio of H2 to CO in the synthesis gas if the feed consists of an equimolar mixture of steam and methane,

d.) Repeat part c) for a steam to methane mole ratio in the feed of 2.0.

e.) How could the feed composition be altered to yield a lower ratio of H2 to CO in the synthesis gas than is obtained in part c.) ?

f.) Is there any danger that carbon will deposit by the reaction :



under conditions of part (c) ? Part d ? If so, how could the feed be altered to prevent carbon deposition ?

2 comments:

ahayles said...

I came to the same conclusion you did about the decrease in temperature but when I used P = 100 bar my EOR1/EOR2 ratio was 77,595 i.e. the second reaction barely occurred. Can this possibly be right?

Dr. B said...

ahayles 4:23 PM

I considered pressures of 0.5, 0.9, 1, 1.1, 1.5 bar and calculated e1/e2. I found that in the neighborhood of 1 bar, increasing P decreased e1/e2. I did not try it for 100 bar. I just tried it at 100 bar and I got e1/e2 = 8...which is not good at all. I would say something is wrong with your work. Bring your Excel to office hours on Wed if you cannot get the problem solved in Quiz Section on Tue.