Evaluation of the Transient Behaviour of a Fixed-Bed Biomass Gasifier for Demand-Oriented Electricity Production

Fixed-bed biomass gasification is a promising dispatchable option of renewable energy sources to serve flexibility demands in electricity production. To experimentally investigate this potential, this contribution analyses an industrial small-scale fixed-bed biomass gasification system for demand-oriented electricity production by evaluating the effects of an electric power change in terms of transition duration and control accuracy. Therefore, the steady-state operation at different loads and the transient behaviour of the gasification system during stepwise changes of the electric power are evaluated based on measured and derived process parameters. The results from a great number of test runs performed reveal the potential for rapid changes of the electric power (100 kW to 150 kW in less than 1.5 min), a good stationary accuracy for operations at nominal (150 kW ± 3.7 kW) and partial load (100 kW ± 5.1 kW), and hardly any negative effects on the gasification performance (e.g. cold gas efficiency and equivalence ratio remain almost constant during load changes). However, results from partial load reveal an increase in process fluctuations due to the control strategy used. To unleash the systems’ full potential of flexibility, a more advanced control strategy should be applied.