Use of solar energy to increase the thermal content of Lignite Water SlurriesInstitute for Solid Fuels Technology and Applications (ISFTA)in collaboration with:Technological Educational Institute (TEI) of Western MacedoniaMechanical Engineering DepartmentLaboratory of Fluid Mechanics

The OrganizationsISFTA - Institute for Solid Fuels Technology and Applications main objective is the promotion of research and technological development aiming at the improved and integrated exploitation of solid fuels and their by-products.research activities are focused mainly on the improvement of solid fuels utilization methods and techniques for power production purposes.TEI - Technological Educational Institute higher degree State Educational Institute.courses and research activities are oriented to applied technologies and applied research.

The regional problemLignite, a solid fuel, is available in large quantities in Dytiki Makedonia and in countries participating in SMART (e.g. Poland). Lignite production in Dytiki Makedonia for 2004 was about 54,5 million tons, which produced at local power plants of the Public Power Corporation (PPC) about 25.250 GWh of electrical power, approximately 60% of the total power generation in Greece. It is evident that the local community is vitally affected by this activity, in both economic and environmental aspects.

The ideaImprovement of the overall efficiency of the local lignite power plants (now at 30% maximum) is of critical importance, as this improvement will reduce the specific investment and operating costs. At the same time, it will decrease the environmental harmful emissions. This challenge may be managed by combining two technologies, solar energy exploitation and lignite combustion, in the form of LigniteWater Slurries (LWS).

The LigniteWater Slurries (LWS)The lignitewater slurry is a form of dense suspension of lignite particles in water, of lignite concentration up to 65%. A small amount of chemical additives is necessary (mainly surfactants)It is easy to handle as fluid (transportation in pipelines, storage in tanks) and by atomization in burners is an auxiliary lignite compatible, fuel.The physicochemical properties of these suspensions, however, are of great importance in relation to the application of these suspensions. For instance, the viscosity is related to the transportation process (pressure drop, selection of the pumps etc.).

The project objectivesIn a next stage of the process, where such slurries are used as pre-heated combustion fuels, reduce formation of NOx can be observed due to the lower flame temperatures.Thus, another important goal of the present project is to develop the methodology for the design and production of more efficient, environmental friendly fuels for power generation.To use solar energy to increase the thermal content of LWS by utilising transparent transportation tubes.In this way, a significant part of the energy needed for drying of the raw lignite, produced in the mines, could be gained by heat exchange.

Phase 1: Design of the testing facilityOutputs Final flow sheet of the facilityPhase 2: Construction of testing facility Outputs i) flow loop utilizing solar energy for thermal treatment of lignite-water suspensions. ii) investigation of the main parameters related to the flow conditions (temperature control, heat exchange capability, etc.)

Phase 3: Testing on LWSOutputs i) investigation of the mechanical phenomena and fluid dynamics within the processing devices ii) standard methods and protocols for characterising flows of lignite-water slurry fluids Outputs i) evaluated methods and protocols for characterising flows of LWS ii) a databank of generic information for characterising these fluidsiii) overall evaluation of the project Phase 4: Evaluation of results

Phase 1: Design of the testing facilityOutcome

12,5 cm50 cm1,9 cm200 cmi) Pump Head : 2,8 bar (max rotation speed)ii) Inoxx parabolic surfaces (5 mm thickness),iii) Plexiglas tubesv) 4 points of temperature measurements, along with 4 points of pressure measurementsSun Rays

Phase 2: Construction of testing facility Outcome

Phase 2: Construction of testing facility Outcome

Phase 3: Testing the facility with LWSOutcome

Phase 3: Testing the facility with LWSOutcome

Phase 4: Evaluation of resultsOutcome

Lignite-Water Slurry having 28%wt. lignite13 September 2007

Phase 4: Evaluation of resultsOutcome

An effort to correlate the solar energy incidence (in Watt/m2) on the parabolic surfaces to the gained energy (through the T (in oC) along with the specific heat coefficient Cp, is undertaken at the moment, in order to estimate the net efficiency of the facility

Phase 3: Testing the facility with LWS(Unexpected situations make the real research an interesting activity)

Phase 3: Testing the facility with LWS(Unexpected situations make the real research an interesting activity)

THANK YOU FOR YOUR ATTENTIONInstitute for Solid Fuels Technology and Applications (ISFTA)in collaboration with:Technological Educational Institute (TEI) of Western MacedoniaMechanical Engineering DepartmentLaboratory of Fluid Mechanics