For the first time, a mathematical model has been proposed to describe the influence of blending ratio on the synergy in co-pyrolysis. The model is based on the stability of a new cross-compound AnB formed between the pyrolysis products of the blend components. A new characteristic, named synergy factor (δ), has been introduced to express the synergy formula. The value of δ and synergy in oil yield are positive when AnB is volatile or soluble in the solvents applied for oil separation. As an example, the model deduced was proved in the mathematical processing of earlier published experimental results on the co-pyrolysis of oil shale and pine wood in supercritical water at 380 °C during 4 hours. The values of δ were estimated for the subsequent distribution of the pyrolysate into water extract (including ether soluble and insoluble extracts), water insoluble oil (including benzene and acetone extracts), solid residue, and gas and pyrogenetic water.
1. Di Nola, G., de Jong, W., Spliethoff, H. TG-FTIR characterization of coal and biomass single fuels and blends under slow heating rate conditions: Partitioning of the fuel-bound nitrogen. Fuel Process. Technol., 2010, 91(1), 103–115.
http://dx.doi.org/10.1016/j.fuproc.2009.09.001
2. Vuthaluru, H. B. Thermal behaviour of coal/biomass blends during co-pyrolysis. Fuel Process. Technol., 2004, 85(2–3), 141–155.
http://dx.doi.org/10.1016/S0378-3820(03)00112-7
3. Ulloa, C. A., Gordon, A. L., García, X. A. Thermogravimetric study of interactions in the pyrolysis of blends of coal with radiata pine sawdust. Fuel Process. Technol., 2009, 90(4), 583–590.
http://dx.doi.org/10.1016/j.fuproc.2008.12.015
4. Meesri, C., Moghtaderi, B. Lack of synergetic effects in the pyrolytic characteristics of woody biomass/coal blends under low and high heating rate regimes. Biomass Bioenerg., 2002, 23(1), 55–66.
http://dx.doi.org/10.1016/S0961-9534(02)00034-X
5. Moghtaderi, B., Meesri, C., Wall, T. F. Pyrolytic characteristics of blended coal and woody biomass. Fuel, 2004, 83(6), 745–750.
http://dx.doi.org/10.1016/j.fuel.2003.05.003
6. Sonobe, T., Worasuwannarak, N., Pipatmanomai, S. Synergies in co-pyrolysis of Thai lignite and corncob. Fuel. Process. Technol., 2008, 89(12), 1371–1378.
http://dx.doi.org/10.1016/j.fuproc.2008.06.006
7. Weiland, N. T., Means, N. C., Morreale, B. D. Product distributions from isothermal co-pyrolysis of coal and biomass. Fuel, 2012, 94, 563–570.
http://dx.doi.org/10.1016/j.fuel.2011.10.046
8. Jones, J. M., Kubacki, M., Kubica, K., Ross, A. B., Williams, A. Devolatilisation characteristics of coal and biomass. J. Anal. Appl. Pyrol., 2005, 74(1–2), 502–511.
http://dx.doi.org/10.1016/j.jaap.2004.11.018
9. Haykiri-Acma, H., Yaman, S., Interaction between biomass and different rank coals during co-pyrolysis. Renew. Energ., 2010, 35(1), 288–292.
http://dx.doi.org/10.1016/j.renene.2009.08.001
10. Zhang, L., Xu, S., Zhao, W., Liu, S. Co-pyrolysis of biomass and coal in a free fall reactor. Fuel, 2007, 86(3), 353–359.
http://dx.doi.org/10.1016/j.fuel.2006.07.004
11. Blesa, M. J., Miranda, J. L., Moliner, R., Izquierdo, M. T., Palacios, J. M. Low-temperature co-pyrolysis of a low-rank coal and biomass to prepare smokeless fuel briquettes. J. Anal. Appl. Pyrol., 2003, 70(2), 665–677.
http://dx.doi.org/10.1016/S0165-2370(03)00047-0
12. Park, D. K., Kim, S. D., Lee, S. H., Lee, J. G. Co-pyrolysis characteristics of sawdust and coal blend in TGA and a fixed bed reactor. Bioresource Technol., 2010, 101(15), 6151–6156.
http://dx.doi.org/10.1016/j.biortech.2010.02.087
13. Yuan, S., Dai, Z.-H., Zhou, Z.-J., Chen, X.-L., Yu, G.-S., Wang, F.-C. Rapid co-pyrolysis of rice straw and a bituminous coal in a high-frequency furnace and gasification of the residual char. Bioresource Technol., 2012, 109, 188–197.
http://dx.doi.org/10.1016/j.biortech.2012.01.019
14. Cao, Q., Jin, L., Bao, W., Lv, Y. Investigations into the characteristics of oils produced from co-pyrolysis of biomass and tire. Fuel Process. Technol. 2009, 90(3), 337–342.
http://dx.doi.org/10.1016/j.fuproc.2008.10.005
15. Acar, P., Sinağ, A., Misirlioğlu, Z., Canel, M. The pyrolysis of scrap tire with lignite. Energ. Source Part A., 2011, 34(3), 287–295.
http://dx.doi.org/10.1080/15567030903586063
16. Sharypov, V. I., Beregovtsova, N. G., Kuznetsov, B. N., Cebolla, V. L., Collura, S., Finqueneisel, G., Zimny, T., Weber, J. V. Influence of reaction parameters on brown coal–polyolefinic plastic co-pyrolysis behavior. J. Anal. Appl. Pyrol., 2007, 78(2), 257–264.
http://dx.doi.org/10.1016/j.jaap.2006.08.004
17. Sharypov, V. I., Marin, N., Beregovtsova, N. G., Baryshnikov, S. V., Kuznetsov, B. N, Cebolla, V. L., Weber, J. V. Co-pyrolysis of wood biomass and synthetic polymer mixtures. Part I: influence of experimental conditions on the evolution of solids, liquids and gases. J. Anal. Appl. Pyrol., 2002, 64(1), 15–28.
http://dx.doi.org/10.1016/S0165-2370(01)00167-X
18. Sharypov, V. I., Beregovtsova, N. G., Kuznetsov, B. N., Membrado, L., Cebolla, V. L., Marin, N., Weber, J. V. Co-pyrolysis of wood biomass and synthetic polymers mixtures. Part III: Characterisation of heavy products. J. Anal. Appl. Pyrol., 2003, 67(2), 325–340.
http://dx.doi.org/10.1016/S0165-2370(02)00071-2
19. Sharypov, V. I., Beregovtsova, N. G., Kuznetsov, B. N., Baryshnikov, S. V., Cebolla, V. L., Weber, J. V., Collura, S., Finqueneisel, G., Zimny, T. Co-pyrolysis of wood biomass and synthetic polymers mixtures. Part IV: Catalytic pyrolysis of pine wood and polyolefinic polymers mixtures in hydrogen atmosphere. J. Anal. Appl. Pyrol., 2006, 76(1–2), 265–270.
http://dx.doi.org/10.1016/j.jaap.2005.12.006
20. Yang, F.-S., Qu, J.-L., Yang, Z.-Y., Zhou, A.-N. Thermal decomposition behavior and kinetics of composites from coal and polyethylene. J. China Univ. Mining Technol., 2007, 17(1), 25–29.
http://dx.doi.org/10.1016/S1006-1266(07)60006-6
21. Suelves, I., Lázaro, M. J., Moliner, R. Synergetic effects in the co-pyrolysis of samca coal and model aliphatic compounds studied by analytical pyrolysis. J. Anal. Appl. Pyrol., 2002, 65(2), 197–206.
http://dx.doi.org/10.1016/S0165-2370(01)00194-2
22. Tiikma, L. Utilization of Plastic Wastes with Oil Shale. ISBN 978-3-8433-5019-8. LAP Lambert Academic Publishing AG, Saarbrücken, Germany, 2010. http://www.superbookshop.net/covers/198/9783843350198.jpg
23. Tiikma, L., Luik, H., Pryadka, N. Co-pyrolysis of Estonian shales with low-density polyethylene. Oil Shale, 2004, 21(1), 75–85.
24. Aboulkas, A., El Harfi, K., Nadifiyine, M., El Bouadili, A. Investigation on pyrolysis of Moroccan oil shale/plastic mixtures by thermogravimetric analysis. Fuel Process. Technol., 2008, 89(11), 1000–1006.
http://dx.doi.org/10.1016/j.fuproc.2008.03.011
25. Aboulkas, A., Makayssi, T., Bilali, L., El Harfi, K., Nadifiyine, M., Benchanaa, M. Co-pyrolysis of oil shale and plastics: Influence of pyrolysis parameters on the product yields. Fuel Process. Technol., 2012, 96, 209–213.
http://dx.doi.org/10.1016/j.fuproc.2011.12.001
26. Veski, R., Palu, V., Kruusement K. Co-liquefaction of kukersite oil shale and pine wood in supercritical water. Oil Shale, 2006, 23(3), 236–248.
27. Zhang, Qi, Chang, Jie, Wang, Tiejun, Xu, Ying. Review of biomass pyrolysis oil properties and upgrading research. Energ. Convers. Manage., 2007, 48(1), 87–92.http://dx.doi.org/10.1016/j.enconman.2006.05.010