Convergence of species in reacting flow on fluent
 

Hi everybody

Please help me

I am trying to simulate combustion reaction in fluent
Residual of variables i. e, continuity, velocity, turbulence (k-epsilon), energy, radiation (DO), and species is good and acceptable but residual of 4 component (CO, O2, CH4 and H2) is around 0.01 and no convergence.

I attached fluent figure. Can anyone help me?
Is there a good way to control species residuals like as Multigrid type, solution method and etc?

Also i select second order for solution method.

Best Regard