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Coal and biomass gasification

In the field of coal and biomass gasification for distributed power generation, Sotacarbo (together with ENEA, the University Cagliari, the University of Campania “Luigi Vanvitelli” and Centro Combustione Ambiente) are developing a number of  experimental activities in demonstration-scale plants, with the aim of setting up technologies for combined heat and power (CHP) generation.

In particular, the experimental activities are based on two main demonstration-scale gasification units: a 5 MWth fixed-bed up-draft gasifier and a new 500 kWth bubbling fluidized-bed reactor (currently under construction).

Current activities are mainly focused on the development of the fixed-bed up-draft gasification process, with the aim of determining the optimum operation conditions for different kinds of biomass (wood chips), in some cases mixed with coal. More than 1000 hours of experimental tests have been performed in the demo-scale unit since 2012. The tests are focused on the minimization of unburnt material in the bottom ashes, the optimization of syngas composition (used to feed an internal combustion engine) and the reduction of tar formation.

Starting from the main operating problems of the original design, a new design for rotating grate assembly has been recently conceived, in close cooperation with ENEA, and it is now being tested with very promising preliminary results. A key issue in the short-term is the design and implementation of a new syngas clean-up section to meet the syngas quality requirements required by commercial syngas-feed power generation units. Other issues relate to the design and implementation of an automatic feedstock loading system and some changes and optimization are being applied to the cooling water jacket system. Future developments include the optimization and the automation of the process and of the timing of fuel loading and ash discharging. The declared objective is to demonstrate a full concept 1 MWe sized gasification plant, fed by coal and biomass, connected to the grid for power generation.

In parallel, new research for the development of bubbling fluidized-bed gasification technologies for small-scale applications (100-500 kWe) is ongoing. Extensive experiments campaign will start in early 2018 on the new demonstration-scale plant, which is currently under construction.