An analysis for compressible flows in a packed bed with metathesis gas–solid reaction

Taking into consideration the mass exchange between gas and solid, and the density change of gas mixture due to reaction, a model is proposed for compressible flows in a packed bed with isothermal metathesis gas–solid reaction aA(g) + bB(s) = cC(g) + dD(s), When a ≠ c, the ratio c/a greatly affects the flows of gas mixture, but for a = c, this coupled model reduces to the non-coupled model. One-dimensional numerical solutions show that the velocity profiles obtained from coupled model greatly differ from that from the non-coupled model. The radius of pellets can change the velocity variation trend. The concentration profiles obtained from this coupled model also differ from that from the non-coupled model. A coupled model accounting for only mass exchange between gas and solid, but neglecting the density change of gas mixture due to reaction will produce an extra term, which results in a great deviation of the velocity and concentration from those from the more comprehensive coupled model.