Hello everyone,

Iam simulating the coal gasification process in Eulerian framework. Mixture-air and mixture-coal are two phases. For Mixture-coal, the particulate stresses are solved using KTGF model. I have the following queries.

a. Coal is composed of char (solid carbon), volatiles (hv_vol), ash (SiC), moisture (h2o). In this volatiles and moisture are not solid phases in reality. But still, should they be considered in the mixture-coal phase as species?

b. For coal devolatilization reaction, Kobayashi two-equation method is most widely used in literature (Eq. (1)). In this, it has two rate constants which lead to two-reaction. How to include two reaction rates for one reaction in UDF?

c. Eq. (1)-(2) are mentioned as heterogeneous in the literature. So the volatiles, tar, and moisture should be considered in mixture-coal? If that is the case, then in the KTGF model an averaged density is required in which the densities of volatile, moisture will also be used. But in reality, these are not solid phases.

d. How to obtain the chemical formula of volatile that is required for the reaction rate?

Eq. (1): volatile-----> 0.07CO+0.01CO2+0.03CH4+0.03H2+0.02H20

A1 = 2*10^5 s-1, E1 =104600 J/mol,

A2 = 1.3*10^7 s-1, E2 = 167400 J/mol

K1 = A1 exp (-E1/RT), K2 = A2 exp (-E2/RT)

Eq. (2): mositure---- >H2O

Any clarification will be greatly helpful.

Thank you in advance