CFD Modeling of a LabScale Microwave Plasma Reactor for WastetoEnergy Applications: A Review
Abstract
:1. Introduction
2. Materials and Methods
3. EMIPG System and Process Description
3.1. EMIPG System Physical Description
3.2. EMIPG Reactor Physical Description
3.3. Reaction Kinetics within an EMIPG Reactor
3.4. Governing Equations within an EMIPG Reactor
3.5. Modeling Tools/Software for an EMIPG Reactor
4. Forward Look and Conclusions
4.1. Forward Look
4.2. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Conflicts of Interest
Disclaimer
References
 Menniti, D.; Burgio, A.; Scordino, N. Population growth, sustainable development, energy resources and environmental protection: The nuclear option. In Proceedings of the 2007 IEEE Lausanne POWERTECH, Lausanne, Switzerland, 1–5 July 2007; pp. 1812–1816. [Google Scholar]
 Kaza, S.; Yao, L.; BhadaTata, P.; Van Woerden, F. WHAT A WASTE 2.0 A Global Snapshot of Solid Waste Management to 2050 OVERVIEW; U.S. Army Research Laboratory: Aldephi, MD, USA, Reprint from Journal of Intelligence Community Research and Development; 21 September 2012. [Google Scholar]
 Charis, G.; Danha, G.; Muzenda, E.; Muzenda, E.; Patel, B.; Mateescu, C.; Muzenda, E. Waste to Energy Opportunities in Botswana: A Case Study Review. In Proceedings of the 2019 7th International Renewable and Sustainable Energy Conference, IRSEC 2019, Agadir, Morocco, 27–30 November 2019; Institute of Electrical and Electronics Engineers Inc.: Piscataway, NJ, USA, 2019. [Google Scholar]
 Frimpong, S. Global Energy Security: The Case for a Multifaceted Solution Strategy. J. Energy Eng. 2008, 134, 109–110. [Google Scholar] [CrossRef]
 Shittu, O.S.; Williams, I.D.; Shaw, P.J. Global Ewaste management: Can WEEE make a difference? A review of ewaste trends, legislation, contemporary issues and future challenges. Waste Manag. 2021, 120, 549–563. [Google Scholar] [CrossRef]
 Haque, M.S.; Uddin, S.; Sayem, S.M.; Mohib, K.M. Coronavirus disease 2019 (COVID19) induced waste scenario: A short overview. J. Environ. Chem. Eng. 2021, 9, 104660. [Google Scholar] [CrossRef]
 US Department of Defense. Task Force on Energy Systems for Forward/Remote Operating Bases; US Department of Defense: Washington, DC, USA, 2016.
 Meier, A.; Shah, M.; Engeling, K.; Quinn, K. Demonstration of Plasma Assisted Waste Conversion to Gas. In Proceedings of the 49th International Conference on Environmental Systems, Boston, MA, USA, 7–11 July 2019; pp. 1–13. [Google Scholar]
 Tang, L.; Huang, H.; Hao, H.; Zhao, K. Development of plasma pyrolysis/gasification systems for energy efficient and environmentally sound waste disposal. J. Electrostat. 2013, 71, 839–847. [Google Scholar] [CrossRef]
 Perkins, G. Production of electricity and chemicals using gasification of municipal solid wastes. In Waste Biorefinery; Elsevier: Amsterdam, The Netherlands, 2020; pp. 3–39. [Google Scholar]
 Blaisi, N.I.; Roessler, J.G.; Watts, B.E.; Paris, J.; Ferraro, C.C.; Townsend, T.G. Construction material properties of high temperature arc gasification slag as a portland cement replacement. J. Clean. Prod. 2018, 196, 1266–1272. [Google Scholar] [CrossRef]
 Arena, U. Process and technological aspects of municipal solid waste gasification. A review. Waste Manag. 2012, 32, 625–639. [Google Scholar] [CrossRef] [PubMed]
 Breeze, P. Advanced WastetoEnergy Technologies. In Energy from Waste; Elsevier: Amsterdam, The Netherlands, 2018; pp. 65–75. [Google Scholar]
 Sekiguchi, H.; Orimo, T. Gasification of polyethylene using steam plasma generated by microwave discharge. Thin Solid Films 2004, 457, 44–47. [Google Scholar] [CrossRef]
 Uhm, H.S.; Na, Y.H.; Hong, Y.C.; Shin, D.H.; Cho, C.H. Production of hydrogenrich synthetic gas from lowgrade coals by microwave steamplasmas. Int. J. Hydrogen Energy 2014, 39, 4351–4355. [Google Scholar] [CrossRef]
 Sanlisoy, A.; Carpinlioglu, M.O. A review on plasma gasification for solid waste disposal. Int. J. Hydrogen Energy 2017, 42, 1361–1365. [Google Scholar] [CrossRef]
 Ho, G.S.; Faizal, H.M.; Ani, F.N. Microwave induced plasma for solid fuels and waste processing: A review on affecting factors and performance criteria. Waste Manag. 2017, 69, 423–430. [Google Scholar] [CrossRef] [PubMed]
 Delikonstantis, E.; Sturm, G.; Stankiewicz, A.I.; Bosmans, A.; Scapinello, M.; Dreiser, C.; Lade, O.; Brand, S.; Stefanidis, G.D. Biomass gasification in microwave plasma: An experimental feasibility study with a side stream from a fermentation reactor. Chem. Eng. Process. Process Intensif. 2019, 141, 107538. [Google Scholar] [CrossRef]
 Wu, T.N. Environmental perspectives of microwave applications as remedial alternatives: Review. Pract. Period. Hazardous Toxic Radioact. Waste Manag. 2008, 12, 102–115. [Google Scholar] [CrossRef][Green Version]
 Munir, M.T.; Mardon, I.; AlZuhair, S.; Shawabkeh, A.; Saqib, N.U. Plasma gasification of municipal solid waste for wastetovalue processing. Renew. Sustain. Energy Rev. 2019, 116, 109461. [Google Scholar] [CrossRef]
 Saleem, F.; Harris, J.; Zhang, K.; Harvey, A. Nonthermal plasma as a promising route for the removal of tar from the product gas of biomass gasification—A critical review. Chem. Eng. J. 2020, 382, 122761. [Google Scholar] [CrossRef]
 Saleem, F.; Rehman, A.; Abbas, A.; Hussain Khoja, A.; Ahmad, F.; Liu, L.; Zhang, K.; Harvey, A. A comparison of the decomposition of biomass gasification tar compound in CO, CO2, H2 and N2 carrier gases using nonthermal plasma. J. Energy Inst. 2021, 97, 161–168. [Google Scholar] [CrossRef]
 Dharmaraj, S.; Ashokkumar, V.; Pandiyan, R.; Halimatul Munawaroh, H.S.; Chew, K.W.; Chen, W.H.; Ngamcharussrivichai, C. Pyrolysis: An effective technique for degradation of COVID19 medical wastes. Chemosphere 2021, 275, 130092. [Google Scholar] [CrossRef] [PubMed]
 Chicone, C. Problems and Projects: Waveguides, Lord Kelvin’s Model. In An Invitation to Applied Mathematics; Elsevier: Amsterdam, The Netherlands, 2017; pp. 775–791. [Google Scholar]
 Hong, Y.C.; Lee, S.J.; Shin, D.H.; Kim, Y.J.; Lee, B.J.; Cho, S.Y.; Chang, H.S. Syngas production from gasification of brown coal in a microwave torch plasma. Energy 2012, 47, 36–40. [Google Scholar] [CrossRef]
 Ellison, C.R.; Hoff, R.; Mărculescu, C.; Boldor, D. Investigation of microwaveassisted pyrolysis of biomass with char in a rectangular waveguide applicator with builtin phaseshifting. Appl. Energy 2020, 259, 114217. [Google Scholar] [CrossRef]
 Sun, H.; Lee, J.; Bak, M.S. Experiments and modeling of atmospheric pressure microwave plasma reforming of a methanecarbon dioxide mixture. J. CO2 Util. 2021, 46, 101464. [Google Scholar] [CrossRef]
 Vecten, S.; Wilkinson, M.; Martin, A.; Dexter, A.; Bimbo, N.; Dawson, R.; Herbert, B. Experimental study of steam and carbon dioxide microwave plasma for advanced thermal treatment application. Energy 2020, 207, 118086. [Google Scholar] [CrossRef]
 Vecten, S.; Wilkinson, M.; Bimbo, N.; Dawson, R.; Herbert, B.M.J. Experimental investigation of the temperature distribution in a microwaveinduced plasma reactor. Fuel Process. Technol. 2021, 212, 106631. [Google Scholar] [CrossRef]
 Yoon, S.J.; Lee, J.G. Syngas Production from Coal through Microwave Plasma Gasification: Influence of Oxygen, Steam, and Coal Particle Size. Energy Fuels 2011, 26, 524–529. [Google Scholar] [CrossRef]
 Yoon, S.J.; Yun, Y.M.; Seo, M.W.; Kim, Y.K.; Ra, H.W.; Lee, J.G. Hydrogen and syngas production from glycerol through microwave plasma gasification. Int. J. Hydrogen Energy 2013, 38, 14559–14567. [Google Scholar] [CrossRef]
 Shin, D.H.; Hong, Y.C.; Lee, S.J.; Kim, Y.J.; Cho, C.H.; Ma, S.H.; Chun, S.M.; Lee, B.J.; Uhm, H.S. A pure steam microwave plasma torch: Gasification of powdered coal in the plasma. Surf. Coat. Technol. 2013, 228, S520–S523. [Google Scholar] [CrossRef]
 Su, L.; Kumar, R.; Ogungbesan, B.; Sassi, M. Experimental investigation of gas heating and dissociation in a microwave plasma torch at atmospheric pressure. Energy Convers. Manag. 2014, 78, 695–703. [Google Scholar] [CrossRef]
 Lin, K.C.; Lin, Y.C.; Hsiao, Y.H. Microwave plasma studies of Spirulina algae pyrolysis with relevance to hydrogen production. Energy 2014, 64, 567–574. [Google Scholar] [CrossRef]
 Tsai, C.H.; Chen, K.T. Production of hydrogen and nano carbon powders from direct plasmalysis of methane. Int. J. Hydrogen Energy 2009, 34, 833–838. [Google Scholar] [CrossRef]
 Wang, Y.F.; You, Y.S.; Tsai, C.H.; Wang, L.C. Production of hydrogen by plasmareforming of methanol. Int. J. Hydrogen Energy 2010, 35, 9637–9640. [Google Scholar] [CrossRef]
 Sturm, G.S.J.; Munoz, A.N.; Aravind, P.V.; Stefanidis, G.D. MicrowaveDriven Plasma Gasification for Biomass Waste Treatment at Miniature Scale. IEEE Trans. Plasma Sci. 2016, 44, 670–678. [Google Scholar] [CrossRef][Green Version]
 Hrycak, B.; Czylkowski, D.; Miotk, R.; Dors, M.; Jasinski, M.; Mizeraczyk, J. Application of atmospheric pressure microwave plasma source for hydrogen production from ethanol. Int. J. Hydrog. Energy 2014, 39, 14184–14190. [Google Scholar] [CrossRef]
 Su, X.; Jin, H.; Guo, L.; Guo, S.; Ge, Z. Experimental study on Zhundong coal gasification in supercritical water with a quartz reactor: Reaction kinetics and pathway. Int. J. Hydrogen Energy 2015, 40, 7424–7432. [Google Scholar] [CrossRef]
 Chanthakett, A.; Arif, M.T.; Khan, M.M.K.; Oo, A.M.T. Performance assessment of gasification reactors for sustainable management of municipal solid waste. J. Environ. Manag. 2021, 291, 112661. [Google Scholar] [CrossRef]
 Okino, A.; Miyahara, H.; Yabuta, H.; Mizusawa, Y.; Doi, T.; Watanabe, M.; Hotta, E. Development of a new multiplasma gas inductively coupled plasma torch. In Proceedings of the IEEE International Conference on Plasma Science, Baltimore, MD, USA, 1 July 2004; p. 306. [Google Scholar]
 Pintsuk, G.; Hasegawa, A. Tungsten as a PlasmaFacing Material. In Comprehensive Nuclear Materials; Elsevier: Amsterdam, The Netherlands, 2020; pp. 19–53. [Google Scholar]
 Ebeling, W. Coulomb interaction and ionization equilibrium in partially ionized plasmas. Physica 1969, 43, 293–306. [Google Scholar] [CrossRef]
 Makonnen, Y.; Beauchemin, D. The inductively coupled plasma as a source for optical emission spectrometry and mass spectrometry. In Sample Introduction Systems in ICPMS and ICPOES; Elsevier: Amsterdam, The Netherlands, 2020; pp. 1–55. [Google Scholar]
 Pattiya, A. Direct Thermochemical Liquefaction for Energy Applications Fast Pyrolysis; Woodhead Publishing: Sawston, UK, 2018. [Google Scholar] [CrossRef]
 Yoon, S.J.; Lee, J.G. Hydrogenrich syngas production through coal and charcoal gasification using microwave steam and air plasma torch. Int. J. Hydrog. Energy 2012, 37, 17093–17100. [Google Scholar] [CrossRef]
 Ibrahimoglu, B.; Cucen, A.; Yilmazoglu, M.Z. Numerical modeling of a downdraft plasma gasification reactor. Int. J. Hydrogen Energy 2017, 42, 2583–2591. [Google Scholar] [CrossRef]
 Silva, V.B.R.E.; Cardoso, J. Introduction and overview of using computational fluid dynamics tools. In Computational Fluid Dynamics Applied to WastetoEnergy Processes; Elsevier: Amsterdam, The Netherlands, 2020; pp. 3–28. [Google Scholar]
 Kobayashi, H.; Howard, J.B.; Sarofim, A.F. Coal devolatilization at high temperatures. Symp. Combust. 1977, 16, 411–425. [Google Scholar] [CrossRef]
 Kuo, P.C.; Illathukandy, B.; Wu, W.; Chang, J.S. Plasma gasification performances of various raw and torrefied biomass materials using different gasifying agents. Bioresour. Technol. 2020, 314, 123740. [Google Scholar] [CrossRef]
 Park, D.C.; Day, S.J.; Nelson, P.F. Formation of Ncontaining gasphase species from char gasification in steam. Fuel 2008, 87, 807–814. [Google Scholar] [CrossRef]
 Gai, C.; Dong, Y.; Zhang, T. Distribution of sulfur species in gaseous and condensed phase during downdraft gasification of corn straw. Energy 2014, 64, 248–258. [Google Scholar] [CrossRef]
 Kuo, P.C.; Wu, W.; Chen, W.H. Gasification performances of raw and torrefied biomass in a downdraft fixed bed gasifier using thermodynamic analysis. Fuel 2014, 117, 1231–1241. [Google Scholar] [CrossRef]
 Ibrahimoglu, B.; Yilmazoglu, M.Z. Numerical modeling of a downdraft plasma coal gasifier with plasma reactions. Int. J. Hydrogen Energy 2020, 45, 3532–3548. [Google Scholar] [CrossRef]
 Silva, V.B.R.E.; Cardoso, J. How to approach a real CFD problem—A decisionmaking process for gasification. In Computational Fluid Dynamics Applied to WastetoEnergy Processes; Elsevier: Amsterdam, The Netherlands, 2020; pp. 29–83. [Google Scholar]
 Badzioch, S.; Hawksley, P.G.W. Kinetics of Thermal Decomposition of Pulverized Coal Particles. Ind. Eng. Chem. Process Des. Dev. 1970, 9, 521–530. [Google Scholar] [CrossRef]
 Fan, F.; Wang, S.; Yang, S.; Hu, J.; Wang, H. Numerical investigation of gas thermal property in the gasification process of a spouted bed gasifier. Appl. Therm. Eng. 2020, 181, 115917. [Google Scholar] [CrossRef]
 Couto, N.; Silva, V.B.; Bispo, C.; Rouboa, A. From laboratorial to pilot fluidized bed reactors: Analysis of the scaleup phenomenon. Energy Convers. Manag. 2016, 119, 177–186. [Google Scholar] [CrossRef]
 Couto, N.; Silva, V.; Monteiro, E.; Teixeira, S.; Chacartegui, R.; Bouziane, K.; Brito, P.S.D.; Rouboa, A. Numerical and experimental analysis of municipal solid wastes gasification process. Appl. Therm. Eng. 2015, 78, 185–195. [Google Scholar] [CrossRef]
 Reactor Design & Simulation  Ansys. Available online: https://www.ansys.com/solutions/solutionsbyindustry/materialsandchemicalprocessing/reactordesign (accessed on 22 February 2021).
 Thompson, M.K.; Thompson, J.M. Introduction to ANSYS and Finite Element Modeling. In ANSYS Mechanical APDL for Finite Element Analysis; Elsevier: Amsterdam, The Netherlands, 2017; pp. 1–9. [Google Scholar]
 About Ansys. Available online: https://www.ansys.com/aboutansys (accessed on 22 February 2021).
 Liu, T.; Zhao, D. Numeric simulation and analysis of H 2O 2 premixed combustion based on OpenFOAM. In Proceedings of the 2012 IEEE Symposium on Robotics and Applications, ISRA 2012, Kuala Lumpur, Malaysia, 3–5 June 2012; pp. 27–30. [Google Scholar]
 OpenFOAM. Available online: https://www.openfoam.com/ (accessed on 18 May 2021).
 Ansys CFX  IndustryLeading CFD Software. Available online: https://www.ansys.com/products/fluids/ansyscfx (accessed on 18 May 2021).
 Barbu, B.; Iturregi, A.; Berger, F.; Torres, E. Numerical analysis of the electric arc simulation using ansys CFX. In IET Conference Publications; IET: London, UK, 2012; Volume 2012, pp. 311–316. [Google Scholar]
 Yadav, H.N.S.; Kumar, M.; Kumar, A.; Das, M. COMSOL simulation of microwave plasma polishing on different surfaces. Mater. Today Proc. 2021. [Google Scholar] [CrossRef]
 COMSOL Multiphysics® Software–Understand, Predict, and Optimize. Available online: https://www.comsol.com/comsolmultiphysics (accessed on 18 May 2021).
 Krusch, S.; Scherer, V.; Solimene, R.; Senneca, O. Assessment of coal pyrolysis kinetics for Barracuda or Ansys Fluent. Energy Procedia 2019, 158, 1999–2004. [Google Scholar] [CrossRef]
 Research and General FluidizationCPFD Software. Available online: https://cpfdsoftware.com/applications/generalfluidization/ (accessed on 18 May 2021).
Source  Advantage 

[16]  Lower voltage requirement than other plasma generator methods. 
[17]  Lower setup cost due to its ability to operate under atmospheric conditions, also allowing the system to be much more compact in size. 
[16,18]  Works without an electrode arrangement so that it avoids operational problems specific to electrode utilization. 
[19]  Microwave energy has already shown its ability to safely combust a variety of hazardous wastes through previous remedial applications. 
Source  Power Setting  Magnetron  Waveguide  MFC  ThreeStub Tuner  Data Collection Equipment  Other Equipment 

[28]  1–6 kW  2.45 GHz (Sairem GMP G4 60 K T400)  WR340  Alicat Scientific, Tucson AZ, USA  Yes  3 thermocouples, HR 2000+ES spectrometer (Ocean Optics Inc., Largo, FL, USA)  E3000 precision steam generators 
[29]  2–5 kW  2.45 GHz (Sairem GMP G4 60 K T400)  WR340  Alicat Scientific, Tucson AZ, USA  Yes  4 type K thermocouples, HR2000+ ES spectrometer (Ocean Optics Inc., Largo, FL, USA)  E3000 precision steam generators 
[18]  Up to 6 kW  2.45 GHz (N.S.)  WR340  Bronkhorst F210 AV50 K  N.S.  Offline microgas chromatograph (microGC, Varian CP4900), sampling bags (Tedlar, 15 L)  Impedance tuner, solid feeder 
[30,31]  1–1.8 kW  2.45 GHz (SM 745, Richardson Electronics)  N.S.  Brooks 5850  Yes  2 Rtype and 5 Ktype thermocouples, GC HP 6890, TCD Carbosphere 80/100 packed column, Alltech  Glycerol preheater and feeder, steam supplier, gear pump (Cole Parmer, 74014750), syringe pump, band heater 
[25]  4 kW  2.45 GHz (N.S.)  WR340  N.S.  Yes  Gas analyzer (N.S.)  Quartz plate installed in the end of tapered waveguide 
[32]  5 kW  2.45 GHz (N.S.)  Twisted Waveguide  N.S.  Yes  Gas analyzer (N.S.)  Quartz plate installed in the end of tapered waveguide 
[33]  1.2–1.6 kW  2.45 GHz (N.S.)  WR248  N.S.  Yes  Optical emission spectroscopy system, transmission stage, optical fiber bundle, spectrometer, CCD camera, data acquisition unit  Forward and backward power meter controller 
[34]  0.8, 0.9, and 1 kW  Not specified  N.S.  N.S.  Yes  GC/TCD, RGA, ESEM, EA (N.S.)  Voltage regulator, cooling water 
[35]  0.8–1.8 kW  2.45 GHz (National Electronics YJ1600)  WR340  N.S.  Yes  GC, FTIR  Cavity resonator 
[36]  0.8–1.4 kW  2.45 GHz (National Electronics YJ1600)  ASTEX WR340  N.S.  Yes  GC/TCD, FTIR, MS  Cavity resonator 
[37]  Up to 6 kW  2.45 GHz (N.S.)  WR340  Bronkhorst F201 AV50 K  Yes  GC, collection bags (N.S.)  Variable reflector, Sairem SAS for all microwave circuits, impedance transformer 
[38]  Up to 6 kW  915 MHz, 2.45 GHz  WR975, WR430  N.S.  GC (Shimadzu GC2014 and SRI 8610 C), FTIR (Thermo Nicolet 380), optical emission spectroscopy (CVI DK480), CCD camera  Water cooling, ferrite circulator with water load, directional coupler, moveable plunger 
Source  Feedstock  Rate of Feedstock Input  Reactor Geometry  Operating Pressure  Carrier Gases/PlasmaForming Gases  Rate of Carrier Gas/PlasmaForming Gases Input  Ignition Source  Reactor Temperature 

[28]  None  None  Quartz tube (L: 450 mm, OD: 25.6 mm, ID: 30 mm)  Atmospheric  H_{2}O, CO_{2}  20–50 g/min, 20–80 SLPM  Inserted tungsten rod  Up to 6300 °C 
[29]  None  None  Quartz tube (L: 35 cm, OD: 25.6 mm, ID: 30 mm)  Atmospheric  H_{2}O, CO_{2}, Air  10–50 g/min (up to 200 °C), 0–100 SLPM, 0–100 SLPM  Inserted tungsten rod  Up to 6300 °C 
[18]  CH_{1.5}O_{.49}  09–13 g/s  Quartz Tube (L: 50 mm, OD: 34 mm, ID: 30 mm)  Atmospheric  Air, N_{2}  8.5–10 NL/min, 17.9–25 NL/min  Used plasmaforming gas (N_{2})  973–2173 K 
[30,31]  Coal  1 g/min  Quartz Tube (L:100 cm, ID: 5.8 cm)  Atmospheric  N_{2}, O_{2}, steam  15 L/min, 0–1.0 L/min, 0–1.5 mL/min  Used plasmaforming gas (N_{2})  Above 3000 °C 
[31]  Glycerol  3 g/min  Quartz Tube (L:100cm, ID: 5.8 cm)  Atmospheric  N_{2}, O_{2}, steam  15 L/min, 0–2.6 L/min, 0–7.2 mL/min  Used plasmaforming gas (N_{2})  N.S. 
[25]  Coal  0–3.75 kg/h  Quartz tube (L: N.S., OD: 30 mm, thickness: 1.5 mm)  Atmospheric  O_{2}, air  20 L/min, 15 L/min  Inserted tungsten rod  2000–6500 K 
[32]  Coal  160 mol coal powder/h  Quartz tube (L: N.S., OD: 30 mm, thickness: 1.5 mm)  Atmospheric  O_{2}  14 mol/h  N.S.  5000 °C 
[33]  None  None  Quartz tube (2.54 cm in diameter and 22.5 cm in length)  Atmospheric  Air, N_{2}, Ar  30 L/min60 L/min  Inserted tungsten rod  5446–6100 K 
[34]  Spirulina algae  1 g of dry Spirulina algae  Quartz tube (L: 35 cm, OD: 3.3 cm, ID: 2.9 cm)  Atmospheric  N_{2}  12 L/min  N.S.  1063–1121 K 
[35]  CH_{4}  12–18 SLPM  Quartz tube (OD: 3.3 cm)  Atmospheric  N_{2}  12–18 SLPM  N.S.  N.S. 
[36]  Methanol  12.4 SLPM  Quartz tube (ID: 2.9 cm)  Atmospheric  N_{2}  N.S.  N.S.  1500 K 
[37]  Cellulose  0.5 g/s  Quartz tube (ID: 31 mm, wall thickness: 2 mm)  Atmospheric  Air  15–20 NL/min  Inserted ignition electrode system  4000–5000 K 
[38]  Ethanol  Introduced into system via bubbler @ 20 °C and 3% v/v  Quartz tube (N.S.)  Atmospheric  CO_{2}, N_{2}, Ar  1500–3900 NL/h  N.S.  Up to 6000 K 
Relationship  Effect 

O_{2}tofeedstock ratio 

Steamtofeedstock ratio 

Gasification efficiency 

Microwave power 

Rate of feedstock input 

Reaction Name  Stoichiometric Description 

Devolatilization  $C{H}_{x}{O}_{y}{N}_{z}{S}_{w}\to Char+Volatiles$ 
Oxidation  $C+0.5{O}_{2}\to CO,\Delta {H}^{0}=268{\mathrm{kJ}\text{}\mathrm{mol}}^{1}$ $C+{O}_{2}\to C{O}_{2},\Delta {H}^{0}=406{\mathrm{kJ}\text{}\mathrm{mol}}^{1}$ 
Water gas reaction  $C+{H}_{2}O\to CO+{H}_{2},\Delta {H}^{0}=131.4{\mathrm{kJ}\text{}\mathrm{mol}}^{1}$ 
Water gas shift  $CO+{H}_{2}O\leftrightarrow C{O}_{2}+{H}_{2},\Delta {H}^{0}=42{\text{}\mathrm{kJ}\text{}\mathrm{mol}}^{1}$ 
Boudouard  $C+C{O}_{2}\to 2CO,\Delta {H}^{0}=172.6{\mathrm{kJ}\text{}\mathrm{mol}}^{1}$ 
Methanation  $C+2{H}_{2}\leftrightarrow C{H}_{4},\Delta {H}^{0}=75{\mathrm{kJ}\text{}\mathrm{mol}}^{1}$ 
Steam methane reforming  $C{H}_{4}+{H}_{2}O\leftrightarrow CO+3{H}_{2},\Delta {H}^{0}=206{\mathrm{kJ}\text{}\mathrm{mol}}^{1}$ 
Nitrogenous species  $CharN\stackrel{H}{\to}HCN$ $HCN+{H}_{2}O\to N{H}_{3}+CO$ 
Sulfur species  ${H}_{2}S+C{O}_{2}\to COS+{H}_{2}O$ ${H}_{2}S+CO\to COS+{H}_{2}$ 
Source  Reactor Type  Modeling Software  Model Used  Devolatilization Considered  Equations/Models Implemented 

[47]  Downdraft Plasma Coal and Biomass Gasifier Reactor  ANSYS Fluent  FRC/EDM  Yes  FRC/EDM Devolatilization: single rate model 
[54]  Downdraft plasma coal gasifier reactor  ANSYS Fluent  FRC/EDM  Yes  FRC/EDM Devolatilization: single rate model 
[55]  Pilotscale plasma bubbling fluidized bed reactor  ANSYS Fluent  FRC/EDM  Yes  FRC/EDM Devolatilization: userdefined function (UDF) using single rate model developed by Badzioch and Hawsley [56]. 
[6]  Updraft plasma gasifier reactor  ANSYS Fluent  FRC/EDM  Yes  FRC/EDM Devolatilization: UDF 
[50]  Downdraft plasma gasifier reactor  Aspen Plus  N.S.  Yes  HCOALGEN model: used to estimate the heat of combustion, heat of formation, and heat capacity of feedstock. DCOALIGT model: used to calculate the density of the feedstock. 
[57]  Plasma spouted bed gasifier  OpenFOAM  N.S.  Yes  Multiphase particleincell approach (MPPICFoam) CoalChemistryFoam 
Source  Mass Balance Model  Momentum Model  Energy Conservation Model  Turbulence Model 

[55]  Solid phase: $\frac{\partial}{\partial t}\left({\alpha}_{s}{\rho}_{s}\right)+\nabla \xb7\left({\alpha}_{s}{\rho}_{s}{\overrightarrow{v}}_{s}\right)={S}_{sg}$ Gas phase: $\frac{\partial}{\partial t}\left({\alpha}_{g}{\rho}_{g}\right)+\nabla \xb7\left({\alpha}_{g}{\rho}_{g}{\overrightarrow{v}}_{g}\right)={S}_{gs}$ Supporting equations: ${S}_{sg}={S}_{gs}={M}_{c}{{\displaystyle \sum}}^{\text{}}{\gamma}_{c}{R}_{c}$ $\frac{1}{{\rho}_{g}}=\frac{RT}{p}{\displaystyle \sum}_{i=1}^{n}\frac{{Y}_{i}}{{M}_{i}}$  Solid phase: $\frac{\partial}{\partial t}\left({\alpha}_{s}{\rho}_{s}{\overrightarrow{v}}_{s}\right)+\nabla \xb7\left({\alpha}_{s}{\rho}_{s}{\overrightarrow{v}}_{s}{\overrightarrow{v}}_{s}\right)={\alpha}_{s}\xb7\nabla {p}_{s}+\nabla \xb7{\alpha}_{s}{\overline{\tau}}_{s}+{\alpha}_{s}{p}_{s}\overrightarrow{g}+\beta \left({\overrightarrow{v}}_{g}{\overrightarrow{v}}_{s}\right)+{S}_{sg}{U}_{s}$ Gas phase: $\frac{\partial}{\partial t}\left({\alpha}_{g}{\rho}_{g}{\overrightarrow{v}}_{g}\right)+\nabla \xb7\left({\alpha}_{g}{\rho}_{g}{\overrightarrow{v}}_{g}{\overrightarrow{v}}_{g}\right)={\alpha}_{g}\xb7\nabla {p}_{g}+\nabla \xb7{\alpha}_{g}{\overline{\tau}}_{g}+{\alpha}_{g}{p}_{g}\overrightarrow{g}+\beta \left({\overrightarrow{v}}_{g}{\overrightarrow{v}}_{s}\right)+{S}_{gs}{U}_{s}$  Gas and solid phases: $\frac{\partial}{\partial t}\left({\alpha}_{q}{\rho}_{q}{h}_{q}\right)+\nabla \xb7\left({\alpha}_{q}{\rho}_{q}{\overrightarrow{v}}_{q}{h}_{q}\right)={\alpha}_{q}\frac{\partial}{\partial t}\left({\rho}_{q}\right)+{\overline{\tau}}_{q}:\nabla \xb7{\overrightarrow{v}}_{q}:\nabla \xb7{\overrightarrow{q}}_{q}+{S}_{q}+{\displaystyle \sum}_{p=1}^{n}\left({\overrightarrow{Q}}_{pq}+{\dot{m}}_{pq}{h}_{pq}{\dot{m}}_{pq}{h}_{pq}\right)$ Supporting equations: ${\overrightarrow{Q}}_{pq}={h}_{pq}\left({T}_{p}{T}_{q}\right)$ ${h}_{pq}=\frac{6{k}_{p}{\alpha}_{q}{\alpha}_{p}{N}_{{u}_{q}}}{{d}_{p}^{2}}$ ${N}_{{u}_{s}}=\frac{{h}_{gs}{d}_{s}}{{k}_{g}}=\left(710{\alpha}_{g}+5{\alpha}_{g}^{2}\right)\left(1+0.7R{e}_{s}{}_{s}^{0.2}P{r}_{g}^{0.33}\right)+\left(1.332.4{\alpha}_{g}+1.2{\alpha}_{g}^{2}\right)R{e}_{s}^{0.7}P{r}_{g}^{0.33}$  $\mathit{k}\mathbf{}\mathit{\epsilon}$model: $\frac{\partial}{\partial t}\left(\rho k\right)+\frac{\partial}{\partial {x}_{i}}\left(\rho {k}_{{u}_{i}}\right)=\frac{\partial}{\partial {x}_{j}}\left[\left(\mu +\frac{{\mu}_{i}}{{\sigma}_{k}}\right)\right]+{G}_{k}+{G}_{b}\rho \epsilon {Y}_{m}+{S}_{k}$ $\frac{\partial}{\partial t}\left(\rho \epsilon \right)+\frac{\partial}{\partial {x}_{i}}\left(\rho {\epsilon}_{{v}_{i}}\right)=\frac{\partial}{\partial {x}_{j}}\left[\left(\mu +\frac{{\mu}_{i}}{{\sigma}_{\epsilon}}\right)\frac{\partial \epsilon}{\partial {x}_{j}}\right]+{C}_{1\epsilon}\frac{\epsilon}{k}({G}_{k}+{C}_{3\epsilon}{G}_{b}){C}_{2\epsilon}\rho \frac{{\epsilon}^{2}}{k}+{S}_{\epsilon}$ 
Variable  Term  Variable  Term 

$\rho $  Density  ${\overline{\tau}}_{g}$  Gasphase stress tensor 
$v$  Instantaneous velocity of gas/solid phase  $\beta $  Gas–solid interphase drag coefficient 
$s$  Solidphase subscript  ${U}_{s}$  Mean velocity of solid 
$g$  Gasphase subscript  ${G}_{k}$  Generation of turbulence kinetic energy due to the mean velocity gradients 
S  Mass source term  ${G}_{b}$  Generation of turbulence kinetic energy due to buoyancy 
${R}_{c}$  Reaction rate  ${Y}_{m}$  Contribution of fluctuating dilatation in compressible turbulence to the overall dissipation rate 
${\gamma}_{c}$  Stoichiometric coefficient  ${S}_{\epsilon}$  Userdefined source term 
${M}_{c}$  Molecular weight  ${S}_{k}$  Userdefined source term 
R  Universal gas constant  ${\overrightarrow{Q}}_{pq}$  Heat transfer intensity between fluid phase $p$ and solid phase $q$ 
T  Temperature of gas mixture  ${\overrightarrow{q}}_{q}$  Heat flux 
$p$  Gas pressure  ${S}_{q}$  Source term due to chemical reactions 
${Y}_{i}$  Mass fraction  ${h}_{pq}$  Enthalpy of the interface 
${M}_{i}$  Molecular weight of each species  ${k}_{p}$  Thermal conductivity for phase $p$ 
$R{e}_{s}$  Reynolds number based on diameter of solid phase and relative velocity  $P{r}_{g}$  Prandtl number of the gas phase 
Sources  CFD Software  Developer  Quick Specifications 

[55,61,62]  Fluent  ANSYS 

[55,63,64]  OpenFoam  Open CFD Ltd. 

[55,65,66]  CFX  ANSYS 

[55,67,68]  COMSOL Multiphysics  COMSOL Inc. 

[55,69,70]  Barracuda  CPFD Software LLC. 

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Sedej, O.; Mbonimpa, E. CFD Modeling of a LabScale Microwave Plasma Reactor for WastetoEnergy Applications: A Review. Gases 2021, 1, 133147. https://doi.org/10.3390/gases1030011
Sedej O, Mbonimpa E. CFD Modeling of a LabScale Microwave Plasma Reactor for WastetoEnergy Applications: A Review. Gases. 2021; 1(3):133147. https://doi.org/10.3390/gases1030011
Chicago/Turabian StyleSedej, Owen, and Eric Mbonimpa. 2021. "CFD Modeling of a LabScale Microwave Plasma Reactor for WastetoEnergy Applications: A Review" Gases 1, no. 3: 133147. https://doi.org/10.3390/gases1030011