Published

2018-01-01

Effects of pyrolysis atmosphere on the porous structure and reactivity of chars from middle and high rank coals

Efectos de la atmósfera de pirólisis sobre la estructura porosa y la reactividad de los carbonizados formados desde carbones de alto y mediano rango

Keywords:

Slow pyrolysis, Pore size distribution, large coal particles, Oxy-combustion, Reactivity (en)
Pirólisis lenta, distribución de tamaño de poro, grandes partículas de carbón, Oxy-combustión, reactividad (es)

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Authors

  • Carlos Francisco Valdés Renteria Universidad Nacional de Colombia https://orcid.org/0000-0001-6836-7085
  • Yuli Betancur Guerrero Universidad de Antioquia
  • Diana Patricia López López Universidad de Antioquia
  • Carlos Andrés Gómez Gutiérrez Universidad Nacional de Colombia
  • Farid Chejne Janna Universidad Nacional de Colombia
The influence of a CO2 or N2-based atmosphere on the porous structure and microstructure of the chars obtained from the slow devolatilization (10°C/min) of two coals of different rank (Semi-Anthracite (SA) and High Volatile Bituminous type C (HVBC)) and different particle size distribution was studied. Physicochemical characterization (ultimate and proximate analysis), structural and morphological characterization by Raman spectroscopy, FE-SEM, BET surface area, and volume and diameter microporous by CO2 adsorption measurements were carried out for all the chars. It was found that the kinetic parameters, the physicochemical properties, and reactivity of the chars are different, depending on the pyrolysis atmosphere. It was also determined that for char from SA coal with particle size greater than 0.7mm, the BET surface area increases when the atmosphere is enriched in CO2. This effect appears to be promoted by the interaction of different processes such as intraparticle side reactions (softening, nucleation and coalescence of bubbles, crosslinking, among others), differences in the thermal diffusivity of N2 and CO2, and the reactive effects of the latter. Additionally, tests of oxidative reactivity of chars showed that the char formed in a CO2 atmosphere is more reactive than that formed in N2. With the results of Raman analysis and kinetic parameters quantified, it was concluded that the reaction atmosphere determined the degree of ordering achieved by the char structure and that the thermo-diffusive properties of the reaction atmosphere promoted structural differences in the char even at low heating rates.

Se estudió la influencia de una atmósfera basada en CO2 o N2 sobre la estructura porosa y la microestructura de carbonizados de carbón obtenidos de la pirólisis lenta no isotérmica desde temperatura ambiente hasta 900 °C de dos carbones de diferente rango (Semi-Antracita (SA) y Bituminosos Alto en Volátiles tipo C (BAVC)), y de diferentes distribuciones de tamaño de partícula. Para todos los carbonizados se realizó la caracterización fisicoquímica (Análisis ultimo y próximo), la caracterización morfológica y estructural por combinación de técnicas como espectroscopia Rama, Microscopia electrónica de barrido por emisión de campo (FE-SEM), área superficial (BET - Brunauer-Emmett-Teller) y volumen y diámetro de microporos por mediciones de adsorción en CO2 (Horvath-Kawazoe (HK) method). Se encontró que los parámetros cinéticos, las propiedades fisicoquímicas y la reactividad de los carbonizados de carbón son diferentes dependiendo de la atmósfera de pirólisis. También se determinó que para el carbonizado de carbón de SA, con un tamaño de partícula mayor de 0,7mm, la superficie BET aumenta cuando la atmósfera se enriquece en CO2. Este efecto parece ser promovido por la interacción de diferentes procesos como las reacciones secundarias intrapartícula (ablandamiento, nucleación y coalescencia de burbujas, entrecruzamiento, entre otros), diferencias en la difusividad térmica de N2 y CO2, y los efectos reactivos de este último. Además, los ensayos de reactividad oxidativa de los sólidos mostraron que el carbonizado formado en una atmósfera de CO2 es más reactivo que el formado en N2. Con los resultados del análisis de Raman y los parámetros cinéticos cuantificados, se concluyó que la atmósfera de reacción determinó el grado de ordenación alcanzado por la estructura carbonosa y que las propiedades termo-difusivas de la atmósfera de reacción promovieron diferencias estructurales en el carbonizado, incluso a bajas velocidades de calentamiento.

References

Al-Makhadmeh, L., Maier, J., Al-Harahsheh, M., & Scheffknecht, G. (2013). Oxy-fuel technology: An experimental investigations into oil shale combustion under oxy-fuel conditions. Fuel, 103, 421–429. https://doi. org/10.1016/j.fuel.2012.05.054

Apicella, B., Senneca, O., Russo, C., Heuer, S., Cortese, L., Cerciello, F., … Ciajolo, A. (2016). Separation and characterization of carbonaceous particulate (soot and char) produced from fast pyrolysis of coal in inert and CO atmospheres. Fuel. https://doi.org/10.1016/j.fuel.2016.11.0492

Arenillas, A., Rubiera, F., Pis, J. ., Cuesta, M. ., Iglesias, M. ., Jiménez, A., & Suárez-Ruiz, I. (2003). Thermal behaviour during the pyrolysis of low rank perhydrous coals. Journal of Analytical and Applied Pyrolysis, 68–69, 371–385. https://doi.org/10.1016/S0165-2370(03)00031-7

Bejarano, P. A., & Levendis, Y. A. (2008). Single-coalparticle combustion in O2/N2 and O 2/CO environments. Combustion and Flame, 153(1–2), 270–287. https://doi.org/10.1016/j.combustflame.2007.10.0222

Beyssac, O., Goffé, B., Petitet, J.-P., Froigneux, E., Moreau, M., & Rouzaud, J.-N. (2003). On the characterization of disordered and heterogeneous carbonaceous materials by Raman spectroscopy. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 59(10), 2267–2276. https://doi.org/10.1016/S1386-1425(03)00070-2

Borah, R. C., Ghosh, P., & Rao, P. G. (2008). Devolatilization of coals of North-Eastern India under fluidized bed conditions in oxygen-enriched air. Fuel Processing Technology, 89(12), 1470–1478. https://doi.org/10.1016/j.fuproc.2008.07.011

Borrego, A. G., & Alvarez, D. (2007). Comparison of Chars Obtained under Oxy-Fuel and Conventional Pulverized Coal Combustion Atmospheres. Energy & Fuels, 21(6), 3171–3179. https://doi.org/10.1021/ef700353n

Borrego, A. G., Garavaglia, L., & Kalkreuth, W. D. (2009). Characteristics of high heating rate biomass chars prepared under N2 and CO2 atmospheres. International Journal of Coal Geology, 77(3–4), 409–415. https://doi.org/10.1016/j.coal.2008.06.004

Brix, J., Jensen, P. A., & Jensen, A. D. (2010). Coal devolatilization and char conversion under suspension fired conditions inO2/N2 and O2/CO2 atmospheres. Fuel, 89(11), 3373–3380. https://doi.org/10.1016/j.fuel.2010.03.019

Bu, C., Leckner, B., Chen, X., Gómez-Barea, A., Liu, D., & Pallarès, D. (2015). Devolatilization of a single fuel particle in a fluidized bed under oxy-combustion conditions. Part B: Modeling and comparison with measurements. Combustion and Flame, 162(3), 809–818. https://doi.org/10.1016/j.combustflame.2014.08.011

Bu, C., Pallarès, D., Chen, X., Gómez-Barea, A., Liu, D., Leckner, B., & Lu, P. (2016). Oxy-fuel combustion of a single fuel particle in a fluidized bed: Char combustion characteristics, an experimental study. Chemical Engineering Journal, 287, 649–656. https://doi.org/10.1016/j.cej.2015.11.078

Dufour, A., Ouartassi, B., Bounaceur, R., & Zoulalian, A. (2011). Modelling intra-particle phenomena of biomass pyrolysis. Chemical Engineering Research and Design, 89(10), 2136–2146. https://doi.org/10.1016/j.cherd.2011.01.005

Flynn, J. H., & Wall, L. A. (1966). A quick, direct method for the determination of activation energy from thermogravimetric data. Journal of Polymer Science Part B: Polymer Letters, 4(5), 323–328. https://doi.org/10.1002/pol.1966.110040504

Gavalas, G. R. (1982). Coal pyrolysis. Amsterdam; New York: New York, N.Y: Elsevier Scientific Pub. Co.: Distributors for the U.S. and Canada, Elsevier Science Pub. Co.

Gil, M. V., Riaza, J., Álvarez, L., Pevida, C., Pis, J. J., & Rubiera, F. (2012). Oxy-fuel combustion kinetics and morphology of coal chars obtained in N2 and CO atmospheres in an entrained flow reactor. Applied Energy, 91(1), 67–74. https://doi.org/10.1016/j.apenergy.2011.09.0172

Gonzalo-Tirado, C., & Jiménez, S. (2015). Detailed analysis of the CO oxidation chemistry around a coal char particle under conventional and oxy-fuel combustion conditions. Combustion and Flame, 162(2), 478–485. https://doi.org/10.1016/j.combustflame.2014.08.002

Gonzalo-Tirado, C., Jiménez, S., & Ballester, J. (2013). Kinetics of CO gasification for coals of different ranks under oxy-combustion conditions. Combustion and Flame, 160(2), 411–416. https://doi.org/10.1016/j.combustflame.2012.10.0202

Hayhurst, A. N., & Lawrence, A. D. (1995). The devolatilization of coal and a comparison of chars produced in oxidizing and inert atmospheres in fluidized beds. Combustion and Flame, 100(4), 591–604. https://doi.org/10.1016/00102180(94)00109-6

Hecht, E. S., Shaddix, C. R., Geier, M., Molina, A., & Haynes, B. S. (2012). Effect of CO and steam gasification reactions on the oxy-combustion of pulverized coal char. Combustion and Flame, 159(11), 3437–3447. https://doi.org/10.1016/j.combustflame.2012.06.0092

Heuer, S., Senneca, O., Wütscher, A., Düdder, H., Schiemann, M., Muhler, M., & Scherer, V. (2016). Effects of oxy-fuel conditions on the products of pyrolysis in a drop tube reactor. Fuel Processing Technology, 150, 41–49. https://doi.org/10.1016/j.fuproc.2016.04.034

Ito, O. (1992). Diffuse reflectance spectra of coals in the UVvisible and near-IR regions. Energy & Fuels, 6(5), 662–665. https://doi.org/10.1021/ef00035a019

Johnson, L., Rostam-Abadi, M., Mirza, I., Stephensn, M., & Kruse, C. (1986). Co-pyrolysis of coal and oil shale I: Thermodynamics and kinetics of hydrogen sulfide capture by oil shale. Illinois state geological survey. Retrieved from https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/30_3_CHICAGO_09-85_0274.pdf

Khan, M. R., & Jenkins, R. G. (1985). Thermoplastic properties of coal at elevated pressures: effects of gas atmospheres. Presented at the International Conference on Coal Science, Sydney.

Khatami, R., Stivers, C., Joshi, K., Levendis, Y. A., & Sarofim, A. F. (2012). Combustion behavior of single particles from three different coal ranks and from sugar cane bagasse in O2/N2 and O2/CO atmospheres. Combustion and Flame, 159(3), 1253–1271. https://doi.org/10.1016/j.combustflame.2011.09.0092

Kim, D., Choi, S., Shaddix, C. R., & Geier, M. (2014). Effect of CO gasification reaction on char particle combustion in oxy-fuel conditions. Fuel, 120, 130–140. https://doi.org/10.1016/j.fuel.2013.12.0042

Larsen, J. W. (2004). The effects of dissolved CO on coal structure and properties. International Journal of Coal Geology, 57(1), 63–70. https://doi.org/10.1016/j.coal.2003.08.001

Li, Q., Zhao, C., Chen, X., Wu, W., & Lin, B. (2010). Properties of char particles obtained under O2/N22 and O combustion environments. Chemical Engineering and Processing: Process Intensification, 49(5), 449–459. https://doi.org/10.1016/j.cep.2010.03.007

Li, S., Ma, X., Liu, G., & Guo, M. (2016). A TG–FTIR investigation to the co-pyrolysis of oil shale with coal. Journal of Analytical and Applied Pyrolysis, 120, 540–548. https://doi.org/10.1016/j.jaap.2016.07.009

Li, X., Hayashi, J., & Li, C. (2006). FT-Raman spectroscopic study of the evolution of char structure during the pyrolysis of a Victorian brown coal. Fuel, 85(12–13), 1700–1707. https://doi.org/10.1016/j.fuel.2006.03.008

Li, X., Rathnam, R. K., Yu, J., Wang, Q., Wall, T., & Meesri, C. (2010). Pyrolysis and Combustion Characteristics of an Indonesian Low-Rank Coal under O2/N2 and O Conditions. Energy & Fuels, 24(1), 160–164. https://doi.org/10.1021/ef900533d

Lin-Vien, D. (Ed.). (1991). The Handbook of infrared and raman characteristic frequencies of organic molecules. Boston: Academic Press.

Maffei, T., Khatami, R., Pierucci, S., Faravelli, T., Ranzi, E., & Levendis, Y. A. (2013). Experimental and modeling study of single coal particle combustion in O and Oxy-fuel (O) atmospheres. Combustion and Flame, 160(11), 2559–2572. https://doi.org/10.1016/j.2/CO2 combustflame.2013.06.002

Miao, Z., Wu, G., Li, P., Meng, X., & Zheng, Z. (2012). Investigation into co-pyrolysis characteristics of oil shale and coal. International Journal of Mining Science and Technology, 22(2), 245–249. https://doi.org/10.1016/j.ijmst.2011.09.003

Molina, A., & Shaddix, C. R. (2007). Ignition and devolatilization of pulverized bituminous coal particles during oxygen/carbon dioxide coal combustion. Proceedings of the Combustion Institute, 31(2), 1905–1912. https://doi.org/10.1016/j.proci.2006.08.102

Murphy, J. J., & Shaddix, C. R. (2006). Combustion kinetics of coal chars in oxygen-enriched environments. Combustion and Flame, 144(4), 710–729. https://doi.org/10.1016/j.combustflame.2005.08.039

Niksa, S., Heyd, L. E., Russel, W. B., & Saville, D. A. (1985). On the role of heating rate in rapid coal devolatilization. Symposium (International) on Combustion, 20(1), 1445–1453. https://doi.org/10.1016/S0082-0784(85)80637-8

Oh, M. S. (1985). Softening coal pyrolysis (Thesis). Massachusetts Institute of Technology. Retrieved from http://dspace.mit.edu/handle/1721.1/15245

Ozawa, T. (1965). A New Method of Analyzing Thermogravimetric Data. Bulletin of the Chemical Society of Japan, 38(11), 1881–1886. https://doi.org/10.1246/bcsj.38.1881

Perera, M. S. A., Ranjith, P. G., Choi, S. K., Bouazza, A., Kodikara, J., & Airey, D. (2011). A review of coal properties pertinent to carbon dioxide sequestration in coal seams: with special reference to Victorian brown coals. Environmental Earth Sciences, 64(1), 223–235. https://doi.org/10.1007/s12665-010-0841-7

Pielsticker, S., Heuer, S., Senneca, O., Cerciello, F., Salatino, P., Cortese, L., … Kneer, R. (2016). Comparison of pyrolysis test rigs for oxy-fuel conditions. Fuel Processing Technology. https://doi.org/10.1016/j.fuproc.2016.10.010

Prinz, D., Pyckhout-Hintzen, W., & Littke, R. (2004). Development of the meso- and macroporous structure of coals with rank as analysed with small angle neutron scattering and adsorption experiments. Fuel, 83(4–5), 547–556. https://doi.org/10.1016/j.fuel.2003.09.006

Rathnam, R. K., Elliott, L. K., Wall, T. F., Liu, Y., & Moghtaderi, B. (2009). Differences in reactivity of pulverised coal in air (O2/N2) and oxy-fuel (O2/CO) conditions. Fuel Processing Technology, 90(6), 797–802. https://doi.org/10.1016/j.fuproc.2009.02.0092

Reich, S., & Thomsen, C. (2004). Raman spectroscopy of graphite. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 362(1824), 2271–2288. https://doi.org/10.1098/rsta.2004.1454

Riaza, J., Khatami, R., Levendis, Y. A., Álvarez, L., Gil, M. V., Pevida, C., … Pis, J. J. (2014). Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions. Combustion and Flame, 161(4), 1096–1108. https://doi.org/10.1016/j.combustflame.2013.10.004

Ross, D. (2000). Devolatilisation times of coal particles in a fluidised-bed. Fuel, 79(8), 873–883. https://doi.org/10.1016/S0016-2361(99)00227-6

Sakurovs, R., He, L., Melnichenko, Y. B., Radlinski, A. P., Blach, T., Lemmel, H., & Mildner, D. F. R. (2012). Pore size distribution and accessible pore size distribution in bituminous coals. International Journal of Coal Geology, 100, 51–64. https://doi.org/10.1016/j.coal.2012.06.005

Saucedo, M. A., Butel, M., Scott, S. A., Collings, N., & Dennis, J. S. (2015). Significance of gasification during oxy-fuel combustion of a lignite char in a fluidised bed using a fast UEGO sensor. Fuel, 144, 423–438. https://doi.org/10.1016/j.fuel.2014.10.029

Senneca, O., Apicella, B., Heuer, S., Schiemann, M., Scherer, V., Stanzione, F., … Russo, C. (2016). Effects of CO on submicronic carbon particulate (soot) formed during coal pyrolysis in a drop tube reactor. Combustion and Flame, 172, 302–308. https://doi.org/10.1016/j.combustflame.2016.07.0232

Senneca, O., & Cortese, L. (2012). Kinetics of coal oxycombustion by means of different experimental techniques. Fuel, 102, 751–759. https://doi.org/10.1016/j.fuel.2012.05.033

Senneca, O., Salatino, P., & Masi, S. (2005). The influence of char surface oxidation on thermal annealing and loss of combustion reactivity. Proceedings of the Combustion Institute, 30(2), 2223–2230. https://doi.org/10.1016/j.proci.2004.08.156

Sheng, C. (2007). Char structure characterised by Raman spectroscopy and its correlations with combustion reactivity. Fuel, 86(15), 2316–2324. https://doi.org/10.1016/j.fuel.2007.01.029

Shi, L., Liu, Q., Guo, X., Wu, W., & Liu, Z. (2013). Pyrolysis behavior and bonding information of coal — A TGA study. Fuel Processing Technology, 108, 125–132. https://doi.org/10.1016/j.fuproc.2012.06.023

Singer, S., Chen, L., & Ghoniem, A. F. (2013). The influence of gasification reactions on char consumption under oxycombustion conditions: Effects of particle trajectory and conversion. Proceedings of the Combustion Institute, 34(2), 3471–3478. https://doi.org/10.1016/j.proci.2012.07.042

Solomon, P. R., Hamblen, D. G., Carangelo, R. M., Serio, M. A., & Deshpande, G. V. (1988). General model of coal devolatilization. Energy & Fuels, 2(4), 405–422. https://doi.org/10.1021/ef00010a006

Solomon, P. R., Serio, M. A., & Suuberg, E. M. (1992). Coal pyrolysis: Experiments, kinetic rates and mechanisms. Progress in Energy and Combustion Science, 18(2), 133–220. https://doi.org/10.1016/0360-1285(92)90021-R Speight, J. G. (2013). The chemistry and technology of coal (3.ed). Boca Raton, Fla.: CRC Press.

Stark, A. K. (2015, February). Multi-Scale Chemistry Modeling of the Thermochemical Conversion of Biomass in a Fluidized Bed Gasifier (Doctoral Thesis). Massachusetts Institute of Technology, EEUU. Retrieved from http://hdl.handle.net/1721.1/97774

Strezov, V., Lucas, J. A., Evans, T. J., & Strezov, L. (2004). Effect of heating rate on the thermal properties and devolatilisation of coal. Journal of Thermal Analysis and Calorimetry, 78(2), 385–397. https://doi.org/10.1023/B:JTAN.0000046105.01273.61

Su, S., Song, Y., Wang, Y., Li, T., Hu, S., Xiang, J., & Li, C.-Z. (2015). Effects of CO and heating rate on the characteristics of chars prepared in CO22 and N2 atmospheres. Fuel, 142, 243–249. https://doi.org/10.1016/j.fuel.2014.11.025

Thommes, M. (2010). Physical Adsorption Characterization of Nanoporous Materials. Chemie Ingenieur Technik, 82(7), 1059–1073. https://doi.org/10.1002/cite.201000064

Toftegaard, M. B., Brix, J., Jensen, P. A., Glarborg, P., & Jensen, A. D. (2010). Oxy-fuel combustion of solid fuels. Progress in Energy and Combustion Science, 36(5), 581–625. https://doi.org/10.1016/j.pecs.2010.02.001

Tolvanen, H., & Raiko, R. (2014). An experimental study andnumerical modeling of combusting two coal chars in a drop-tube reactor: A comparison between N2/O, and N2/CO2/O atmospheres. Fuel, 124, 190–201. https://doi.org/10.1016/j.fuel.2014.01.1032

Tuinstra, F. (1970). Raman Spectrum of Graphite. The Journal of Chemical Physics, 53(3), 1126. https://doi.org/10.1063/1.1674108

Valdés, Carlos F., Gloria Marrugo, Farid Chejne, Juan David Román, and Jorge I. Montoya (2016). Effect of Atmosphere Reaction and Heating Rate on the Devolatilization of a Colombian Sub-Bituminous Coal. Journal of Analytical and Applied Pyrolysis 121: 93–101

Wang, B., Sun, L., Su, S., Xiang, J., Hu, S., & Fei, H. (2012). Char Structural Evolution during Pyrolysis and Its Influence on Combustion Reactivity in Air and Oxy-Fuel Conditions. Energy & Fuels, 26(3), 1565–1574. https://doi.org/10.1021/ef201723q

Wang, C., Zhang, X., Liu, Y., & Che, D. (2012). Pyrolysis and combustion characteristics of coals in oxyfuel combustion. Applied Energy, 97, 264–273. https://doi.org/10.1016/j.apenergy.2012.02.011

Xu, J., Su, S., Sun, Z., Qing, M., Xiong, Z., Wang, Y., … Xiang, J. (2016). Effects of steam and CO on the characteristics of chars during devolatilization in oxy-steam combustion process. Applied Energy, 182, 20–28. https://doi.org/10.1016/j.apenergy.2016.08.1212

Yan, B.-H., Cao, C.-X., Cheng, Y., Jin, Y., & Cheng, Y. (2014). Experimental investigation on coal devolatilization at high temperatures with different heating rates. Fuel, 117, 1215–1222. https://doi.org/10.1016/j.fuel.2013.08.016

Yin, C., & Yan, J. (2016). Oxy-fuel combustion of pulverized fuels: Combustion fundamentals and modeling. Applied Energy, 162, 742–762. https://doi.org/10.1016/j.apenergy.2015.10.149

Yu, J., Lucas, J. A., & Wall, T. F. (2007). Formation of the structure of chars during devolatilization of pulverized coal and its thermoproperties: A review. Progress in Energy and Combustion Science, 33(2), 135–170. https://doi.org/10.1016/j.pecs.2006.07.003

Zeng, D., Hu, S., & Sarv, H. (2008). Differences in chars formed from coal pyrolysis under N2 and CO atmospheres (p. 12). Presented at the International Pittsburgh Coal Conference 2008, Pittsburgh, PA, USA.2

Zhang, L., Kajitani, S., Umemoto, S., Wang, S., Quyn, D., Song, Y., … Li, C.-Z. (2015). Changes in nascent char structure during the gasification of low-rank coals in CO. Fuel, 158, 711–718. https://doi.org/10.1016/j.fuel.2015.06.0142

Zhu, X., & Sheng, C. (2010). Evolution of the Char Structure of Lignite under Heat Treatment and Its Influences on Combustion Reactivity †. Energy & Fuels, 24(1), 152–159. https://doi.org/10.1021/ef900531h

How to Cite

Effects of pyrolysis atmosphere on the porous structure and reactivity of chars from middle and high rank coals. (2018). Ingeniería E Investigación, 38(1), 31-45. https://doi.org/10.15446/ing.investig.v38n1.64516

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