Haluk Direskeneli Energy Analyst printable version send your friend message to author add comment ()

Tuesday, 21 July 2009

On 16th July 2009 together with a number of leading local businessmen, your writer had the opportunity to have a business lunch in Bursa Botanical Park with new elected Mayor of Bursa Greater Municipality.

Bursa Greater Municipality evaluates takeover possibility of Bursa Keles lignite mine reserves from Turkish Coal Board, and open a tender to construct a new thermal power plant based on CFB steam boiler technology, and make necessary cofiring to dispose the municipality refuse in that plant

That is widely used operation in Northern America and Western Europe.  There is available local technology to construct a thermal power plant based on CFB technology in biomass cofiring of municipality waste with local low quality lignite. 

Municipality disposes the refuse and also generates electricity and creates income for the municipality to use cash in other public projects.

Cofiring is the combustion of two different types of materials at the same time. One of the advantages of cofiring is that an existing plant can be used to burn a new fuel, which may be cheaper or more environmentally friendly. Biomass is sometimes cofired in existing coal plants instead of new biomass plants. Cofiring can also be used to improve the combustion of fuels with low energy content.

As long as the electricity or heat produced with the biomass and landfill gas was otherwise going to be produced with non-renewable fuels, the benefits are essentially equivalent whether they are cofired or combusted alone. Cofiring can be used to lower the emission of some pollutants. Cofiring biomass with coal results in less sulfur emissions than burning coal by itself.

Cofiring (also referred usually as co-firing or co-combustion) is the combustion of two different fuels in the same combustion system. Fuels can be solid fuels, Liquid fuels or gaseous, and its nature either fossil or renewable. Therefore use of heavy fuels assisting coal power stations may be considered technically co-firing.

However the term cofiring is used in the present technological framework to designate combined combustion of two (or more) fuels sustained in the time, as a normal daily practice.

The interest for cofiring and the use of this term sprung in the 80's in the U.S. and Europe, and referred specifically to the use of waste solid residues (paper, plastic, solvents, tars, etc.) or biomass in coal power stations that were initially designed for combustion of sole coal, and attempted, because of existence of those new opportunity fuels, to carry out a combined combustion in order to increase benefit margins. As a matter of fact, this interest on cofiring has grown in the last decade mainly due to the increasing social concerns on global warming and greenhouse gas (GHG) emissions.

Consequences of this concern are the new policies on energy and environment aiming at reducing emissions. Cofiring is regarded as a great opportunity for replacing coal (solid fossil fuel) used for power generation easily with renewable fuels (biomass) with low costs and a direct repercussion in the decrease of greenhouse gas emissions. During the last decades research has provided very diverse solutions for cofiring biomass in coal power stations with a limited impact in efficiency, operation and lifespan.

Power generation with better efficiency: generally biomass power plants produce electricity with relative low efficiency (18 to 22%) respect the huge coal units (32 to 38%) with optimised cycles given the economy of scale

Flexible operation is possible in biomass cofiring.  Original plant can operate still at 100% load with fossil fuel. Co-firing facility is less sensitive to seasonality in biomass production and to biomass availability and price

Incentives for development of biomass markets is widely practiced in diverse European countries where it is proven that the promotion of co-firing is a key for the development of biomass markets as well as for the creation of expertise on biomass handling and combustion.

We shall be too pleased to receive your evaluations and contribution. Your comments are always welcome

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Haluk Direskeneli, Ankara based Energy Analyst