function ferr = f(x)
T = 1200;
TK = T + 273.15;
Keq = exp(-3.112+3317/TK);
FeedH2 = 450;
FeedCO2 = 50;
FeedH2O = 1150;
FeedCO = 500;
ferr = (FeedH2+x).*(FeedCO2+x)./(FeedH2O-x)./(FeedCO-x)-Keq;
