Help: another question on estimating reaction rate constants with mathcad

Alan , thank you so much !!!!!!

you found a very obvious mistake in my model postulates (it should be k2), which I HADN'T FOUND AFTER TIMES OF CHECK LAST NIGHT. thank you, thank you !!! and you update your reply so fast that my reply cannot keep up with you. while i don't think there are any serious mistakes in your earlier solutions

the "Coeff = 22.4*10^6" in my question is just a coefficient used to convert the units of my data from ' ppmv ' into 'mol/L' at standard condition (because I changed solids volume, mass and reactor volume in my experiment). maybe it is not convient for numerical calculaion. So, in your old worksheet, the unit of raw data is actually converted into kmol/L .

a (ppmv) => a (10^ -6) / 22.4(L/mol) = [a / (22.4 * 10^6) ] (mol/L) = [a / (22.4 * 10^3) ] (kmol/L)

btw, parameter 'm' in my question is a explicit function of bulk density, and has a unit of g/L (or kg/m3, actually they are the 'same') according to the unit of gas concentration, so the rate constant unit you got is

e.g. k2: m3_gas/(kg_solid * day) or L/(g * day) ,

but for k1, a little more complicated, will be [kmol^0.5 * L^0.5 * g^-1 *day^-1]

your results for k are

k1 = 6.211 E-05 [kmol^0.5 * L^0.5 * g^-1 *day^-1]
k2 = 5.993 E-05 L/(g day)
k3 = 4.080 E-04 L/(g day)

and your new results are

k1 = 1.878 E-06 [mol^0.5 * L^0.5 * g^-1 *day^-1]
k2 = 6.323 E-05 L/(g day)
k3 = 4.081 E-04 L/(g day)

and my old result for k (in matlab, using lsqnonlin) is

k1 = 1.24 E-06 [mol^0.5 * L^0.5 * g^-1 *day^-1]
k2 = 3.84 E-05 L/(g day)
k3 = 2.66 E-04 L/(g day)

and I think the earlier results make sense.

and the difference between mathcad and matlab is acceptable compared with the difference between the results from different temperatures. I will try some other operating conditions in mathcad......