Combustion and Environment - EU-projects

Opticomb - Optimisation and design of biomass combustion systems


The main objective is to increase the flexibility of biomass combustion plants with respect of fuel input, and substantially reduce the emissions with this technology. To achieve this, results from static studies (Computational Fluid Dynamics (CFD), NOx mechanisms, grate design) have to be implemented with dynamic information of the plant (control concepts). The project can be divided into the following sub objectives:

  • Development and demonstration of advanced control concepts for biomass combustion grate systems.
  • The development of guidelines, including demonstration, to minimise the important emissions of NOx and CO.
  • Improvement of the efficiency (technical and economical) of biomass combustion plants.
  • Design rules for biomass combustion systems and process control systems.
  • The design and testing of a new grate.
Description of the work

The major problems regarding biomass combustion are still the NOx and CO emissions, especially when the fuel becomes more diverse (high peaks during transients). The continuously changing fuel composition, the non-linearity of the process and the multi variability of the process makes it difficult to decrease the emissions further. Therefore classical control strategies are no longer effective. In order to improve the actual process control system, advanced control technologies based upon process models are needed. To achieve this goal static models have to be integrated with dynamic models.

At present, no satisfying tools are available to describe the NOx formation in the fuel layer and the gas phase. Therefore, an extensive study on fuel layer and gas phase NOx formation mechanisms will be performed. The developed mechanisms will be integrated in a CFD combustion model and a static fuel layer model in order to be able to minimise the CO and NOx emission.

Based upon experimental work and plant data, a new grate will be designed. A dynamic furnace model is developed for biomass combustion. Special measurements techniques will be used to gather actual plant data (2 plants, diverse fuels) to validate the models. The stochastic characteristics of the fuel will be revealed , which is used together with the dynamic model to investigate the disturbance rejection capacity of the plant.

All information will be used to develop new control concepts and to design new combustion systems also from a dynamic point of view. These will be tested in an installation.

The environmental survey of the influence of the proposed technology, a market analysis, information dissemination and exploitation strategies will be carried out.

Expected Results and Exploitation plans

The following results are expected:

  • Innovative control concepts for biomass combustion.
  • Furnace concept for a new multi fuel biomass combustion plant.
  • Reduction of CO and NOx by 20-50 %.
  • Higher flexible biomass combustion systems with respect to fuel diversity.
  • Increased energy efficiency and availability.
  • A new multi fuel grate system.
  • A 3D-CFD combustion model for biomass fuels.
  • Dissemination of the results.
  • Cost/benefit analysis.
  • Final report on dissemination and exploitation of OPTICOMB
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