Slow pyrolysis of waste and biomass may represent an interesting solution for renewable energy conversion in highly regenerative Gas Turbine (GT) or Internal Combustion Engines (ICE) based power cycles. The combined production of a medium LHV gas to fuel the GT or the ICE and of a high LHV byproduct (tar and/or char) that may contribute to maintain the pyrolysis process, makes pyrolysis highly competitive when compared to gasification. Nevertheless few simulations of such integrated plants are available in literature also because of the lack of general and robust modeling tools for the pyrolysis process. A pilot scale rotary kiln pyrolyzer was built at the University of Perugia to investigate the main benefits and drawbacks of the technology. The pyrolyzer will provide the experimental data that are necessary both to evaluate mass and energy balances, and to support the pyrolysis simulation activity that the authors are carrying out. Namely the test rig will provide, for each given quantity and composition of the biomass or waste in input, the gas, char and tar yields and compositions and the energy provided to maintain the process. This paper describes the main features and operational possibilities of the plant.