Use of solar energy to increase the thermal content of Lignite – Water Slurries

1. Use of solar energy to increase the thermal content of Lignite – Water Slurries Institute for Solid Fuels Technology and Applications (ISFTA) in collaboration with: Technological Educational Institute (TEI) of Western Macedonia Mechanical Engineering Department Laboratory of Fluid Mechanics

2. The Organizations ISFTA - 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.

3. The regional problem • Lignite, 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.

4. The idea • Improvement 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 Lignite–Water Slurries (LWS).

5. The Lignite–Water Slurries (LWS) • The lignite–water 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.).

6. The project objectives • 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. • In 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.

7. Phase 1: Design of the testing facility • Outputs Final flow sheet of the facility Phase 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.)

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

9. Phase 1: Design of the testing facility • Outcome Sun Rays 200cm 50cm 12,5 cm 1,9cm i) Pump Head : 2,8 bar (max rotation speed) ii) Inoxx parabolic surfaces (5 mm thickness), iii) Plexiglas tubes v) 4 points of temperature measurements, along with 4 points of pressure measurements

10. Phase 2: Construction of testing facility • Outcome

11. Phase 2: Construction of testing facility • Outcome

12. Phase 3: Testing the facility with LWS • Outcome

13. Phase 3: Testing the facility with LWS • Outcome

14. Phase 4: Evaluation of results • Outcome Lignite-Water Slurry having 28%wt. lignite 13 September 2007

15. Phase 4: Evaluation of results • Outcome An effort to correlate the solar energy incidence (in Watt/m2) on the parabolic surfaces to the gained energy (through the ΔT (in oC) along with the specific heat coefficient Cp, is undertaken at the moment, in order to estimate the net efficiency of the facility

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

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

18. THANK YOU FOR YOUR ATTENTION Institute for Solid Fuels Technology and Applications (ISFTA) in collaboration with: Technological Educational Institute (TEI) of Western Macedonia Mechanical Engineering Department Laboratory of Fluid Mechanics