Abstract: A framework is developed to integrate MFiX, an open source multiphase flow solver, with state-of-the-art pre-conditioners and linear solver packages in Trilinos via MFIX, Fortran, C and CPP wrappers. The computations are carried out to simulate flow in a fluidized bed problem with MFiX as well as the integrated solver, MFiX-Trilinos. BiConjugate gradient stabilized method as well as GMRES is used to solve the linear system of equations. The linear system of equations for the flow variable are solved using the built-in solvers in MFiX. On the other hand, MFiX-Trilinos uses the solvers from AztecOO package in Trilinos. The performance of the integrated solver is tested on various computer architectures for variety of problem sizes. The flow from the solver with the integrated framework and MFiX are in good agreement. However, the solver in MFiX-Trilinos is, approximately 30% faster compared to the same solver in MFiX.