1. 1 Mechanical Engineering, Engineering Faculty King Monkut’s Institute of Technology Ladkrabang, Prince of Chumphon Campus Sompong Bangyeekhan, Mech. Eng. Ph,D The effect of the size distribution of para wood pieces in the hopper in relation to the thermal efficiency of the downdraft gasifier

2. 2 Contents 1.Introduction 2.Objectives 3.Scopes 4.Materials and Methods 5.Results and Discussion 6.Conclusion

3. 3 Source: FAO, “Wood gas as engine fuel,” Food and agriculture organization of the United Nations. FAO Forestry paper, vol. 72, 1986, pp. 22-26. 1. Introduction Downdraft UpdraftCrossdraft Fixed batch type gasifier

4. 4 1. Introduction Advantage and disadvantage of downdraft gasifier DisadvantageAdvantage Limit the sizes of the biomass not exceed 2-10 cm Have a little of the oil tar Limit the moistness of the biomass not exceed 25 % DB Limit the sizing distribution during 2-3 inch Limit the quantity per batch during 20-75% of full tank volume

5. 5 1. Introduction Thermo-chemistry of downdraft gasifier C+O 2  CO 2 (1) 2H 2 +O 2  2H 2 O (2) C+CO 2  2CO (3) C+H 2 O  CO+H 2 (4) C+2H 2 O  CO 2 +2H 2 (5) CO+H 2 O  CO 2 +H 2 (6) C+2H 2  CH 4 (7) Dry Biomass + Heat  Charcoal + CO + CO 2 + H 2 O + CH 4 + C 2 H 6 + Pyroligneous Acid + Tars (8) Source: http://www.allpowerlabs.com/wp- content/gallery/gasification- grapics/downdraft.jpg

6. 6 1. Introduction Source: http://www.teedindd.com/ads/1510 24 Length standard cutting is 1.05m

7. 7 2. Objectives 1. For investigated to fine a maximum mixed sizing of para wood pieces for down draft gasifier 3. Scopes 1. Downdraft gasifier have a straight bottleneck in side diameter 20 cm. 2. Control moisture content of wood pieces not over 10.5  1.5 % DB 3. Control cross section area of wood pieces 750 mm 2  50 mm 2 4.Control air inlet = 8.9x10 -4 m 3 /s 5.Input the mixed sizing wood pieces 3 kg.

8. 8 4. Materials and Methods Wood pieces cross section 750mm 2  50mm 2 45-65 mm. 65-90 mm. Sun bask for to reduce the moisture content Moistness 10.5  1.5 % DB

9. 9 4. Materials and Methods Sample No. (%w:%w) Quantity of wood pieces sizing 45-65 mm (kg) (A) Quantity of wood pieces sizing 65-90 mm (kg) (B) 1 (90:10)2.700.30 2 (80:20)2.400.60 3 (70:30)2.100.90 4 (60:40)1.801.20 5 (50:50)1.50 6 (40:60)1.201.80 7 (30:70)0.902.10 8 (20:80)0.602.40 9 (10:90)0.302.70 (A) (B)

10. 10 4. Materials and Methods Result of heating value of wood piece 10.5% (DB) testing by Bomb calorimeter from the science testing service at Walailak University = 17.35 MJ/kg (converse unit into kJ/kg)

11. 11 4. Materials and Methods Water Boiling Test

12. 12 4. Materials and Methods Water Boiling Test  ther is the thermal efficiency (%) m wi is the mass of water initially in cooking vessel (kg) C pw is the specific heat of water (kJ/kg. ๐ C) [4.186 kJ/kg.K] T e is the temperature of boiling water ( ๐ C) T i is the initial temperature of water in pot ( ๐ C) m i,evap is the mass of water evaporated (kg) H 1 is the latent heat of vaporization of water at 373 K (kJ/kg) [2,260kJ/kg] m f is the mass of fuel burned (kg) H f is the caloric value of fuel (kJ/kg) (higher heating value)

13. 13 5. Results and discussions Sample No. Temperature (C) Amount of water evaporate d (g) Burning time for boiling water (min) Wood chips consum ption (kg)  ther Boiling water Initial water X bar SD 1 90:10 95.529.0337.2231.743.41 3.43 0.15 95.829.1340.0221.663.59 96.728.9339.0241.813.30 2 80:20 95.529.0356.7372.802.21 2.22 0.10 96.228.4366.1362.722.33 96.627.9359.8392.952.13 3 70:30 95.130.0446.1493.701.97 1.95 0.03 96.429.5450.0513.861.92 96.529.3453.0503.781.97 Other Sample a No boiling 30.0 --- a Wood pieces with a mixed of more than 70:30 can not be boiled in WBT.

14. 14 5. Results and discussions The results after burning the mixed woodchips show that the downdraft gasifier has a thermal efficiency maximum of 3.43 from the first sample, a ratio of 90:10. While the mixture 8: 2 from the second sample can make the thermal efficiency of the stove was reduce from a mixture 90:10 to 35.5% at 2.22. While the mixture 70:30 of the second sample can make the thermal efficiency of the stove reduce from a mixture 90:10 to 42.5% at 1.95. This is consistent with the principle that the size distribution of the woodchips in the tanks of the downdraft gasifier, the production of the heat of the stove will be lower [4]. The other sample found it impossible to measure because the water did not boil. Test samples show that the piece of wood in the sample (1), (2) and (3) plus the continuation of burning wood that is tested, can be burned well. They cannot get stuck in the fuel tank. The other mixed wood pieces sample of more than 70:30 cannot be boiled in WBT. These samples lodge woodchips in the tank which means water cannot boil. The fire has been exthingushered because the discontinuous woodchips fail to combust. This is consistent with past research that found that the size distribution of wood affects the downdraft gasifier stove [2, 4].

15. 15 6. Concussions A good performance of thermal efficiency and suitable to use when is mixing wood pieces at 80:20. It was found that the downdraft gasifier thermal efficiency should be at 2.22, the thermal efficiencies last similar research was at 2.23-2.24 [2, 3, 8]. While there are the symptoms of congestion in the tank the wood pieces did not jam. The flow of gas is a good fuel gas that flows continuously. The water in an open container is also boiling. The use of wood fuel mixed at 8: 2 to help reduce the time to prepare the wood pieces up to 15% of the pure size 45-65 cm. Which reduces the time to prepare would be help more easily and quickly.

16. 16 Acknowledgements The author thank the King Mongkut’s Institute of Technology Ladkrabang, Prince of Chumphon campus (KMITL PCC) for the support provided for this work.

17. 17 [1]FAO, “Wood gas as engine fuel,” Food and agriculture organization of the United Nations. FAO Forestry paper, vol. 72, 1986, pp. 22-26. [2]B. Sompong, “The effect of size of para wood pieces on the downdraft gasifier thermal efficiency,” The 1st National Conference on IAMBEST. Chumphon. Thailand, pp. 57-63, May 2016. [3]B. Sompong, “The effect of moistness of para wood pieces on the downdraft gasifier thermal efficiency,” The 9th TSAE Internatial Conference. BKK. Thailand, inpress. [4]D. Natthawut, “ Biomass energy technology” August 13, 2016, from http://www.energy.mju.ac.th/download/Chapter%206%20Gasification.pdf [5]K. Rossanee, “Songkhla's commercial rubber price slump, the rubber farmers cut rubber trees to grow other crops” unpublished. [6]K. Suksawat, T. Boonlert, P. Suebsak, “The design and performance testing of downdraft gasifier for the rubber sheet drying process,” Brachelor Degree Dissertation, King Monkut’s Institute of Technology Ladkrabang, Prince of Chumphon. 2016, pp. 42-57. [7]S.C. Bhattacharya, D.O. Albina, Aung Myint Khaing, “Effcts of selected parameters on performance and emission of biomass-fired cookstoves,” Biomass and Bioenergy, vol. 23, 2002, pp. 387-395. [8]P. Mankheed, “The design and performance testing of downdraft gasifier,” The 3rd National Conference on Integration of Thai research within the ASEAN Community Network. Phuket. Thailand, pp. 391-402, December 2014. References

18. 18 Question & Answer Thank you for your Attention