  The conditions in the protoplanetary disc are determinant for the various
planet formation mechanisms. We present a framework which combines
self-consistent disc structures with the calculations of the growth rates of
planetary embryos via pebble accretion, in order to study the formation of
Super-Earths. We first perform 2D hydrodynamical simulations of the inner
discs, considering a grain size distribution with multiple chemical species and
their corresponding size and composition dependent opacities. The resulting
aspect ratios are almost constant with orbital distance, resulting in radially
constant pebble isolation masses, the mass where pebble accretion stops. This
supports the "peas-in-a-pod" constraint from the Kepler observations. The
derived pebble sizes are used to calculate the growth rates of planetary
embryos via pebble accretion. Discs with low levels of turbulence (expressed
through the $\alpha$-viscosity) and/or high dust fragmentation velocities allow
larger particles, hence lead to smaller pebble isolation masses, and the
contrary. At the same time, small pebble sizes lead to low accretion rates. We
find that there is a trade-off between the pebble isolation mass and the growth
timescale with the best set of parameters being an $\alpha$-viscosity of
$10^{-3}$ and a dust fragmentation velocity of 10 m/s, mainly for an initial
gas surface density (at 1 AU) greater than 1000 $\rm{g/cm^2}$. A
self-consistent treatment between the disc structures and the pebble sizes is
thus of crucial importance for planet formation simulations.
