1. DEVELOPMENT OF A BIOMASS PYROLYSIS REACTOR AND CHARACTERISATION OF ITS PRODUCTS FOR INDUSTRIAL APPLICATIONS Department of Mechanical Engineering The Federal University of Technology Akure. Ondo State. Nigeria JANUARY, 2012

2. Introduction It comprises:- aggregate of all biologically produced matter inform of: It comprises:- aggregate of all biologically produced matter inform of:  wood and wood wastes;  agricultural crops and their waste by-products;  municipal solid wastes;  animal wastes;  wastes from food processing;  and aquatic plants including sea weeds and algae (Agarwal and Agarwal, 1999; U.S Dept of Energy, 2003). Biomass is cheap, available, affordable and reliable Biomass is cheap, available, affordable and reliable It’s a regular source of rural energy in Nigeria, fuel wood is cheap, easily accessed by both rural & urban dwellers. It’s a regular source of rural energy in Nigeria, fuel wood is cheap, easily accessed by both rural & urban dwellers. 2

3.  Biomass – renewable, available, and abundant on earth.  It is a versatile energy and chemical resource  It could be converted into renewable products that could significantly supplement the energy needs of society 3

4. Selected Feedstock Species 4 (B) A. africana (A) M. excelsa Fig. 17: Sizing of Selected Feedstock for Pyrolysis Experiments (C) E. guineensis

5. Experimentation and Documentation Carbonisation experiments were carried out at various elevated temperatures for all samples in the developed electrically fired ‘Fixed-Bed Reactor’ at pre-determined temps., ranging from 400°C to 800°C and at 100°C intervals. Fifteen batches (0.5 kg net weight per batch) each of the selected materials of constant moisture content were used as feedstock in 3 replicated experiments 5

6. Experimentation & Documentation Cont… By-products of pyrolysis:  charcoal (solid fuel),  oils (liquid fuel),  and pyrogas (non-condensable gaseous products). Experiments were conducted under a quiescent environment (insufficient or complete absence of air). Feedstock residence time, furnace temp. and pyrolysis (reaction) temp. were recorded as displayed on the controllers and recorded every 5 min. 6

7. Experimental Set-up 7 Fig. 18: Pyrolysis Experimental set-up

8. Assembling the Fixed-Bed Reactor 8 Fig.19 Assembling the reactor for an Experiment

9. 9 Fig. 20: Fully Assembled Fixed-Bed Reactor with an Ongoing Experiment

10. 10 Fig. 21:Dismantling the Reactor after an Experiment

11. 11 Fig. 22: Appearance of the Fixed-Bed Reactor and Furnace at 600 0 C & 700 0 C respectively (During the Day) The appearance of the Fixed-Bed Reactor and Furnace at 600 °C and 700 °C respectively

12. The appearance of the Fixed-Bed Reactor and Furnace at 800 °C 12 Day Appearance Night Appearance Fig. 23: Fixed Bed Reactor after an Experiment

13. Result and Discussion The relationship between Carbonisation and reaction temperatures for the three species were positive but not linear (Fig. 4A). The temperature interactions within species and between species were significant (p<0.05) as shown Fig.4B The mass of the char fractions vary from one species to the other but a general mass reduction across higher temperature profile is generally noticed. Pyrolysis oil yield also varies with temperature The sygas fraction varies with temperature. 13

14. Result and Discussion The mass of the char fractions vary from one species to the other but a general mass reduction across higher temperature profile is generally noticed. Pyrolysis oil yield also varies with temperature The sygas fraction varies with temperature. Pyroligneous oil is used as solvent and insecticide 14

15. 15 S/NoSpeciesCarbonisation Temperature (°C) 400500600700800 React. Temp. 1Apa 334.67±5.03 3 380.33±29.7 04 439.33±2 7.465 512.33±15.3 08 708.67±4. 041 2Iroko 363.00±8.88 8 412.00±5.29 2 487.67±1 5.373 590.67±22.1 21 685.00±2. 000 3PKS 366.00±2.00 0 390.67±19.3 99 520.33±1 3.429 617.00±1.73 2 729.33±1 5.044 F - Value Species Treatment (T R )40.388* Carbonisation Temp.(T C )773.350* Interaction (T R *.T C )7.947* * = significant (p<0.05), R 2 =0.991 Table 6A: Mean and Standard Deviation of Reaction Temperature for all samples Table 6B: Variance ratios (F-calculated) from various ANOVA tables for Reaction Temperature

16. Effect of Carbonisation Temperature on Reaction Temperature 16 Fig. 24: Increase of Reaction Temperature with increasing carbonisation Temperature for all samples

17. Carbonisation Temp N Subset (Reaction Temperatures) 12345 4009354.56 5009394.33 6009482.44 7009573.33 8009707.67 Sig.1.000 17 Table 7: Mean Reaction Temperature between Species Alpha (α) = 0.5

18. Variance ratios (F-calculated) from various ANOVA Tables for Reaction Temperature 18 Table 8: Variance ratios (F-calculated) from various ANOVA Tables for Reaction Temperature F - Value Species Treatment (T R )40.388* Carbonisation Temp. (T C )773.350* Interaction (T R *.T C )7.947* * = significant (p<0.05), R 2 =0.991

19. 19 Fig. 25: Effect of Carbonisation Temperature on Residence Time

20. Recovering Pyro-liquor through Phase change 20 Fig.26: Pyrolysis Liquor Recovery

21. Recovered Pyrolysis Liquor at 400 °C, 500 °C, 600 °C, 700 °C, and 800 °C 21 Pyro-oil from Palm Kernel Pyro-oil from Iroko Wood Pyro-oil from Apa Wood Fig. 27: Pyrolysis oil across selected samples

22. Fig. 28: Acidic - pH for all samples 22

23. 23 Fig.29: Variation of Pyro-oil yield with Carbonisation Temperature

24. 24 Fig.30: Variation of Tar yield with Carbonisation Temperature

25. 25 Fig. 31: Variation of Syngas yield with Carbonisation Temperature

26. 26 Fig. 32: Variation of char yield with carbonisation temperature

27. Recovered Carbon & Smokeless Burning Charcoal 27 Fig. 33: Charring Residues & Smokeless combustion A B C D

28. Residual yield per species (% wt) 28 Fig. 34: Variation of Apa wood residual fractions with carbonisation temperature

29. Residual yield per species (% wt) 29 Fig. 35: Variation of Iroko wood residual fractions with carbonisation temperature

30. Residual yield per species (% wt) 30 Fig. 36: Variation of Iroko wood residual fractions with carbonisation temperature

31. Table 9:Char yield / 1000 kg of feedstock as a function of temperature Temperature ( °C) Iroko Derived charcoal Apa Wood Derived Charcoal PKS Derived Charcoal 400341.46393.66388.46 500334.54356.00354.46 600309.06332.66337.80 700295.20315.86321.06 800278.00270.40309.34 31

32. Table. 10: Pyro-oil yield / 1000 kg of feedstock as a function of temperature Temperature ( °C) Iroko Derived Pyro-oil Apa Wood Derived Pyro-oil PKS Derived Pyro-oil 400339.80329.86341.00 500342.74334.80350.46 600353.06334.14365.40 700359.60329.06365.46 800365.06350.54373.86 32

33. Fig.11: Tar yield / 1000 kg of feedstock as a function of temperature Temperature ( °C) Iroko Derived Tar Apa Wood Derived Tar PKS Derived Tar 40099.1480.2691.94 50097.86100.8098.80 600107.00100.8090.60 700102.66108.7486.66 800100.20104.6693.80 33

34. Fig.12: Syngas yield / 1000 kg of feedstock as a function of temperature Temperature ( °C) Iroko Derived Syngas Apa Wood Derived syngas PKS Derived syngas 400219.60196.20178.60 500224.86208.46196.86 600230.06227.34206.20 700242.60245.86226.80 800254.74274.40223.00 34

35. Material & Products Characterization (1) FTIR and TGA – Analysis (2) Determine: Proximate analysis of parent stock and fractions: M.C, V.M, F. C, & Ash content (4) Determine: Ultimate analysis (Elemental analysis of Parent stock and fractions)- C, H, O, N, S, Ash (5) Energy Content Analysis (HHV) (6) Density

36. Moisture Content Determination The moisture content was determined by using METTLER TOLEDO HB 43-S Hologen, moisture Analyzer. The result is as shown in Table 3. 36

37. Table 5: Moisture Content (%wt/wt) BIOMASS Moisture Content (%wt/wt) REPLICATES (%) MEAN + STDV 1st2nd3rd (i)Apa Wood 4.884.784.894.85 ± 0.06 (ii)Iroko 4.274.404.234.30 ± 0.09 (iii)PKS 4.104.174.244.17 ± 0.07 (iv)Coconut Shell 5.034.914.924.95 ± 0.07 (v)Gmelina Arborea 4.874.904.984.92 ± 0.06 (vi)Bamboo 3.743.993.873.87 ± 0.13 37

38. BIOMASS Volatile Matter (%wt/wt) 1st2ndMean ± STDV (i)Apa WoodA75.3582.0978.72 ± 4.77 (ii)Iroko WoodB82.0681.96282.01 ± 0.07 (iii) Palm Kernel Shell (PKS) C77.0177.2377.12 ± 0.16 (iv)Coconut ShellD82.387.3084.80 ± 3.54 (v)Gmelina ArboreaF93.41490.0891.75 ± 2.36 (vi)BambooE88.71485.0486.88 ± 2.60 Table. 6: BIOMASS Volatile Matter (%wt/wt)

39. Density Determination The materials were ground to pass through 2 mm filter Dried to constant weights in the muffle furnace at 103±2°C and later cooled in the desiccator. Three replicates (0.001kg) measured with high precision ‘METTLER Balance for compression Pelletized in the die at a pressure of 5000 Ib/in 2 (34.5 MN/m 2 ) for all samples. The diameter (D) and height (h) of all the pellets were measured with electronic Veneer Caliper. 39 Density of pellet (ρ) = 4m/(πD^2 h)

40. S/No Selected Tropical Biomass REPLICATES MEAN + STDV 1 st 2 nd 3 rd (i)Apa WoodA 1029.251024.031009.091020.79 ± 10.46 (ii)Iroko WoodB 878.13874.17895.60882.63 ± 11.40 (iii) Palm Kernel Shell (PKS) C 1028.471031.591038.371032.81 ± 5.06 (iv)Coconut ShellD 1078.931066.511105.551083.67± 19.95 (v)Gmelina ArboreaF 850.82857.53845.85851.40 ± 5.86 (vi)BambooE 914.82914.91930.95920.23 ± 9.28 40 Table. 7: Density of Selected Tropical Biomass (kg/m 3 )- Oven dry weight

41. 41

42. PROXIMATE ANALYSIS SAMPLE*P/Stk400500600700800 APA ASH 1.081.31±0.01 e 1.59±0.02 d 1.94±0.01 c 2.21±0.01 b 2.59±0.02 a IROKO0.824.89±0.02 e 6.38±0.49 d 7.45±0.01 c 8.03±0.02 b 8.20±0.01 a PKS2.234.07±0.02 e 5.19±0.02 d 6.17±0.01 c 6.26±0.01 b 6.39±0.11 a APA FC 21.0656.38±0.23 e 63.44±0.09 d 87.33±0.7 8 c 94.02±0.1 9 b 95.36±0.05 a IROKO20.9374.65±0.48 e 77.35±0.06 d 81.54±0.0 4 c 84.38±0.0 2 b 85.13±0.03 a PKS18.4573.65±0.51 e 78.54±0.07 d 83.4±0.02 c 91.64±0.0 5 b 92.3±0.09 a APA VM 77.8642.31±0.22 a 34.97±0.10 b 10.73±0.7 8 c 3.77±0.19 d 2.05±0.04 e IROKO78.2520.46±0.46 a 16.49±0.08 b 11.01±0.0 3 c 7.58±0.01 d 6.66±0.03 a PKS79.3222.28±0.51 a 16.27±0.06 b 10.43±0.0 1 c 2.09±0.05 d 1.29±0.11 e 42

43. Energy Content Determination Samples were pulverized in Ball Mill, made to pass through 2 mm filter and dried to constant weight in an oven at 103±2°C. Parr 1341 Oxygen Bomb Calorimeter was standardized with using benzoic acid in three replicates. The standard energy was determined to be 2437.9 cal/°C (10.207 kJ/°C). Each biomass Pellets was fired in the Bomb Calorimeter and energy determined. 43

44. Table 8: Biomass Energy Determination S/No Selected Tropical Biomass Energy Content (kJ/kg) REPLICATES MEAN + STDV 1 st 2 nd 3 rd (i)Apa WoodA 21.6021.3021.4721.46 ± 0.15 (ii)Iroko WoodB 19.5520.4219.2519.74± 0.61 (iii)Palm Kernel Shell (PKS)C 20.2320.0820.6820.33 ± 0.32 (iv)Coconut ShellD 20.0720.1219.9220.04 ± 0.11 (v)Gmelina ArboreaF 17.8418.5317.1317.83 ± 0.70 (vi)BambooE 19.4617.9118.8818.75 ± 0.78 44

45. CONCLUSION: 45  The electrically controlled thermal reactor plant for the conversion of biomass to charcoal was successfully developed.  The performance of the reactor was evaluated over a temperature range of 400 0 C to 800 0 C and was found to be effective in degrading Palm Kernel (Elaesis Guineensis) Shells, Apa wood (Afzelium Africana) and Iroko wood to charcoal at pre-determined conditions.

46. Conclusion Cont….  Conversion efficiency is higher than reported in literature.  Cycle time is much reduced than reported in literature  Heat promotes the unzipping of biomass polymer chain in thermochemical reactions  Biomass’ rate of mass disappearance is a function of temperature, degree of structural polymerization, thermal conductivity, material density, heating rate, thermal intensity, and residence time among others.  Rapid evolution of volatiles is noticed from 275 ° C to 600 ° C. It reduces drastically to near zero between 700 ° C to 800 ° C for the selected biomass samples. 46

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