SP 1 Innovative fuel preparation and mixing

SP-leader: Vattenfall Research and Development AB

Objectives

The main objectives of this SP are to demonstrate innovative fuel preparation and mixing in order to obtain:

• More cost-effective fuels or fuel mixtures

• Fuels or fuel mixtures which minimise corrosion and fouling

• More fuel flexible systems which satisfies the need of the customer (e.g. handling of sludge and fuels that will lower the operational and maintenance costs)

Also look at lowering the environmental impact of fuels and further improvements in demonstrated technologies.

State of the art

Activities/Demonstrations

Deposits on a superheater formed by the combustion of waste wood	Deposits collected when burning waste wood. Growth rate 21 g/m2/h and a high Cl content	Deposits collected when burning waste wood with an additive. Growth rate 6 g/m2/h and Cl content negligible.The corrosion rate is halved

State of the art

To make the next generation of combustion systems for waste and biomass more cost-effective and efficient they will have to be able to burn a wider range of fuels more efficiently. This means cheaper and potentially more problematic fuels. Biomass and waste have a high content of alkali metals and chlorine which gives rise to corrosive alkali chloride deposits, like KCl, and other low-melting point compounds.This causes widespread fouling and corrosion.

It is thought that a reduction in corrosion and fouling can be achieved by modifying the fuel chemistry. This is a novel approach and will be investigated in the project by using different fuel mixtures, changing the combustion or the use of additives.

Activities/Demonstrations

Several demonstrations supported by research activities will be performed in SP1. The activities that will be included are:

• Short-term demonstration (3 hours periods) of the effect of additives on reduction of corrosion and fouling in superheaters

• Short-term demonstration of the effect of burning different quality biomass fuels

• Long-term demonstration of the effect of additives on reduction of corrosion and fouling in superheaters during one firing season (11 months)

• Long-term demonstration on the effect of using low-grade biomass fuels (waste wood)

• Research supporting both short- and long-term demonstrations with respect to testing of fuels of different quality and fuel mixtures. The research work will also support the understanding of the demonstration activities as well as assess the potential for further improvement