Section A: Generation & storage technologies for the future

Thursday, 14 September 2017, 11:45-12:15h/A05

Co-generation and district heating for the future, based on CFBC and (waste) wood firing

Dr. Frans Van Dijen, EngieLab, Belgium

Engie Lab – Laborelec was recently involved in the conversion of a coal-fired unit to a wood-fired unit, in the city of Paris. The unit supplies heat to the district heating of Paris. In Denmark, a new CFBC unit is anticipated, for district heating. This unit will fire wood as well. ENGIE operates a relatively new CFBC in Poland, which fires wood mainly.

It is assumed, that the (waste) wood fired is so-called sustainable wood. In this way, sustainable heat and sustainable power are produced.

The advantages of modern, centralised wood firing for co-generation and district heating, using a CFBC, are presented, such as:

• Excellent combustion and excellent flue gas purification, which limits fine dust emissions compared to wood-firing in small units at home
• Producing no emissions of N₂O is possible
• Low primary NOx emissions
• Application of an SNCR and/or an SCR are possible
• Disposal of waste wood and wood residues, as Municipal Solid Waste Incineration (MSWI) plants are not fond on fuels with a high heating value
• The ability to generate both medium pressure and/or high pressure steam, and bypassing the steam turbine, for not producing power when the power price is low
• Fuel flexibility, for processing other, suitable fuels, which limits (financial) risks.

A disadvantage is, that producing wood panels from some types of waste wood and wood residues is a better option, at least according to EU waste legislation. However, with time these wood panels become available as waste wood again, and then they should be used as fuel. This is the concept of down-cycling.

Another disadvantage with solid fuel-fired units is, that the quality of new units deteriorated with time. So, both the suppliers and the purchasers of such units must pay much more attention to quality and quality assurance.

Obviously, this technology must compete with other technologies regarding sustainable heat and/or power, which can be difficult.