Assessment of Pilot-scale Pyrolysis Gas Production as Fuel for Cogeneration

Amongst the different waste-to-energy technologies that are available, cogeneration presents an opportunity to reduce fossil fuels consumption and the costs associated with electricity use. The addition of a pyrolysis unit to the cogeneration system allows the simultaneous use of pyrolysis gases for electricity generation, and the production of useful byproducts. Since the calorific value of biofuels affects the efficiency of cogeneration systems, it is relevant to determine the pyrolysis conditions that maximize the calorific value of the pyrolysis gas used in cogeneration. In this sense, the present study aims to explore the effect of different processing temperatures over the calorific value of pyrolysis gases in a pilot-scale case with the purpose of adding this component in cogeneration. In such a context, a single screw pyrolizer was operated at 0.073 MPa using 3.5 kg/min of palm kernel shells as feedstock. Different pyrolysis temperatures were evaluated once the process achieved steady conditions (550, 650, and 750 ºC). Since the scope of this work is the gaseous outputs, the resulting pyrolysis gas samples were cooled down and analyzed with gas chromatography. The results show that higher pyrolysis temperatures are associated with higher energy contents. The pyrolysis gas obtained at 750 ºC showed a calorific value of 14.01 MJ / Nm3.