Microwave pyrolysis experimental study of peat

The work is devoted to the study of the destruction of the top sphagnum peat layer due to microwave radiation. For the analysis of physical and chemical processes, a laboratory setup was created on the basis of a coaxial resonator-reactor having a geometry that ensures a uniform distribution of the microwave field in the reactor volume. An industrial magnetron having a frequency of 2.45 GHz and a power of up to 1 kW was used as a source of microwave radiation. In laboratory studies with a relatively small amount of peat (~ 100 g), the advantage of the created setup consists in the ability to quickly achieve the necessary temperature for the pyrolysis reaction at a relatively low level of microwave power (~ 100 W) in these experiments. The analysis of the products obtained during the reaction was carried out using a gas chromatography mass spectrometer. The research was aimed at creating highly-efficient environmentallyfriendly technologies for processing biofuels characterised by a high yield of combustible gases suitable for further use in industrial power plants, as well as for obtaining a resinous fraction for the production of light hydrocarbons and a carbon residue for modern highly efficient sorbents. On the basis of the experimental setup, studies were carried out on soft microwave pyrolysis of peat at a temperature of 250 °C under constant removal of gaseous reaction products. Samples of solid, liquid and gas phases presenting valuable carbon residues, oily fractions and a pyrolysis gas, respectively, were obtained and analysed. The article examines the possibility for industrial application of reaction products. The chemical composition of the r eaction products during both microwave and “traditional” pyrolysis with thermal heating is compared. The composition of the gases released during microwave pyrolysis is characterised by the absence of heavy toxic gases often accompanying the process of “traditional” thermal pyrolysis. Reducing the amount of toxic gases improves the environmental component of production. This circumstance indicates the prospects of microwave pyrolysis for industrial processing of organic materials.

The authors declare no conflict of interests regarding the publication of this article.

1. Gunich SV, Yanchukovskaya EV. Analysis of processes of pyrolysis of wastes of production and consumption. Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya = Proceedings of Universities. Applied Chemistry and Biotechnology. 2916;6(1):86–93. (In Russian)

2. Kiryaeva TA. Analysis of coal-and-methane geomaterial composition using microwave-assisted pyrolysis of black coal. Interekspo Geo-Sibir'. 2015;2(3):93–96. (In Russian)

3. Yatsun AV, Konovalov PN, Konovalov NP. Microwavepyrolysis ofscraptires in the presence of potassium hydroxide. Sovremennye naukoemkie tekhnologii = Modern high technologies. 2017;2(13):83–87. (In Russian)

4. Gunich SV, Yanchukovskaya EV, Dneprovskaya NI. Analysis of modern methods of hard domestic wastes processing. Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya = Proceedings of Universities. Applied Chemistry and Biotechnology. 2015;(2):110–115. (In Russian)

5. Polishchuk TS, Cherevatyuk GV, Patrusheva OV. The use of microwave radiation in petrochemistry. Molodoi uchenyi = Young scientist. 2017;(2-1):23–27. (In Russian)

6. Yang J, Chen H, Zhao W, Zhou J. TG–FTIRMS study of pyrolysis products evolving from peat. Journal of Analytical and Applied Pyrolysis. 2016;117:296–309. https://doi.org/10.1016/j.jaap.2015.11.002

7. ChenX, Che Q, Li S, Liu Z, Yang H, Chen Y, et al. Recent developments in lignocellulosic biomass catalytic fast pyrolysis: Strategies for the optimization of bio-oil quality and yield. Fuel Processing Technology. 2019;196:106180.

8. Makkawi YT, Sayed YEl, Salih M, Nancarrow P, Banks SW, Bridgwater T. Fast pyrolysis of date palm (Phoenix dactylifera) waste in a bubbling fluidized bed reactor. Renewable Energy. 2019;43: 719–730. https://doi.org/10.1016/j.renene.2019.05.028

9. Lam SS, Wan Mahari WA, Ok YS, Peng W, Chong CT, Ma NL, et al. Microwave vacuum pyrolysis of waste plastic and used cooking oil for simultaneous waste reduction and sustainable energy conversion: Recovery of cleaner liquid fuel and techno-economic analysis. Renewable and Sustainable Energy Reviews. 2019;115:109359. https://doi.org/10.1016/j.rser.2019.109359

10. Khiari B, Jeguirim M. Tunisian agro-food wastes recovery by pyrolysis: Thermogravimetric analysis and kinetic study. 10th International Renewable Energy Congress (IREC). 26–28 March 2019, Sousse, Tunisia. https://doi.org/10.1109/IREC.2019.8754614

11. ZhangY, ChengQ, Wang D, Xia D, Zheng X, Li Z, et al. Preparation of Pyrolytic Carbon from Waste Tires for Methylene Blue Adsorption. JOM. Journal of the Minerals, Metals and Materials Society. 2019;71(10):3658–3666. https://doi.org/10.1007/s11837-019-03658-7

12. Lambert A, Anawati J, Walawalkar M, Tam J, Azimi G. Innovative Application of Microwave Treatment for Recovering of Rare Earth Elements from Phosphogypsum. ACS Sustainable Chemistry and Engineering. 2018;6(12):16471–16481. https://doi.org/10.1021/acssuschemeng.8b03588

13. Wahi R, Abdul Aziz SM, Hamdan S, Ngaini Z. Biochar production from agricultural wastes via low-temperature microwave carbonization. IEEE International RF and Microwave Conference. 2015;4:250–253. https://doi.org/10.1109/RFM.2015.7587754

14. Klinger J, Bar-Ziv E, Shonnard DR, Westover T, Emerson R. Predicting Properties of Gas and Solid Streams by Intrinsic Kinetics of Fast Pyrolysis of Wood. Energy and Fuels. 2016;30(1):318–325. https://doi.org/10.1021/acs.energyfuels.5b01877

15. Markin VI, Cheprasova MYu, Bazarnova NG. General areas of the use of a microwave radiation for processing of plant raw materials (review). Russian Journal of Bioorganic Chemistry. 2015;41(7):686–699. https://doi.org/10.1134/S1068162015070110

16. Borges FC, Du Z-Y, Xie Q, Trierweiler JO, Cheng Y, Wan Y, et al. Fast microwave assisted pyrolysis of biomass using microwave absorbent. Bioresource Technology. 2014;156:267–274. https://doi.org/10.1016/j.biortech.2014.01.038

17. Ren S, Lei H, Wang L, Bu Q, Chen S, Wu J, et al. Microwave pyrolysis of Douglas fir sawdust pellet. American Society of Agricultural and Biological Engineers Annual International Meeting. 2011;2:1334–1348. https://doi.org/10.13031/2013.37300

18. Bogdashov AA, Krapivnitskaya TO, Peskov NYu. Simulation of microwave pyrolysis of peat. In: SVCh-tekhnika i telekommunikatsionnye tekhnologii (CriMiCo’2018): materialy 28-i Mezhdunarodnoi Krymskoi konferentsii = Microwave and Telecommunication Technology (CriMiCo2018): Proceedings of the 28th International Crimean Conference. 9–15 September 2018, Sevastopol. Sevastopol, 2018, vol. 6, p. 1381–1387. (In Russian)

19. Krapivnitskaia TO, Bogdashov AA, Denisenko AN, Glyavin MYu, Kalynov YuK, Kuzikov SV, et al. High-temperature microwave pyrolysis of peat as a method to obtaining liquid and gaseous fuel. EPJ Web of Conferences. 10th International Workshop 2017 “Strong Microwaves and Terahertz Waves: Sources and Applications”. 2017. Vol. 49. 02023. 2 p. https://doi.org/10.1051/epjconf/201714902023

20. Bogdashov AA, Krapivnitskaia TO, Denisenko AN, Peskov NYu, Glyavin MYu, Semenycheva LL, et al. Microwave pyrolysis of peat: results and prospects. In: SVCh-tekhnika i telekommunikatsionnye tekhnologii (CriMiCo’2018): materialy 28-i Mezhdunarodnoi Krymskoi konferentsii = Microwave and Telecommunication Technology (CriMiCo’2018): Proceedings of the 28th International Crimean Conference. 9–15 September 2018, Sevastopol. Sevastopol, 2018, vol. 6, p. 1394–1399. (In Russian)