  We present a self-consistent model of a protoplanetary disk: 'ANDES'
('AccretioN disk with Dust Evolution and Sedimentation'). ANDES is based on a
flexible and extendable modular structure that includes 1) a 1+1D
frequency-dependent continuum radiative transfer module, 2) a module to
calculate the chemical evolution using an extended gas-grain network with
UV/X-ray-driven processes surface reactions, 3) a module to calculate the gas
thermal energy balance, and 4) a 1+1D module that simulates dust grain
evolution. For the first time, grain evolution and time-dependent molecular
chemistry are included in a protoplanetary disk model. We find that grain
growth and sedimentation of large grains to the disk midplane lead to a
dust-depleted atmosphere. Consequently, dust and gas temperatures become higher
in the inner disk (R < 50 AU) and lower in the outer disk (R > 50 AU), in
comparison with the disk model with pristine dust. The response of disk
chemical structure to the dust growth and sedimentation is twofold. First, due
to higher transparency a partly UV-shielded molecular layer is shifted closer
to the dense midplane. Second, the presence of big grains in the disk midplane
delays the freeze-out of volatile gas-phase species such as CO there, while in
adjacent upper layers the depletion is still effective. Molecular
concentrations and thus column densities of many species are enhanced in the
disk model with dust evolution, e.g., CO2, NH2CN, HNO, H2O, HCOOH, HCN, CO. We
also show that time-dependent chemistry is important for a proper description
of gas thermal balance.
