Atmospheric pressure microwave plasma source for hydrogen production M. Jasi  nski a , D. Czylkowski a, *, B. Hrycak a , M. Dors a , J. Mizeraczyk a,b a The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-231 Gda nsk, Poland b Department of Marine Electronics, Gdynia Maritime University, Morska 81-87, 81-225 Gdynia, Poland article info Article history: Received 30 October 2012 Received in revised form 15 May 2013 Accepted 17 May 2013 Available online 17 June 2013 Keywords: Hydrogen production Methane conversion Microwave plasma abstract Nowadays hydrogen is considered as a clean energy carrier and fuel of the future. That is why the interest in production and storage of hydrogen is still increasing. One of the promising technology is using microwave plasma for hydrogen production. In this study we propose two types of an atmospheric pressure microwave plasma source (MPS) for hydrogen production via methane conversion. The first one was a nozzleless waveguide- supplied coaxial-line-based. The second one was a nozzleless waveguide-supplied metal- cylinder-based. They can be operated with microwave frequency of 2.45 GHz and power up to a few kW with a high gas flow rates (up to several thousands l/h). We present experi- mental results concerning electrical properties of the MPS, plasma visualization, spectro- scopic diagnostics and hydrogen production. The experiment was carried out with methane flow rate up to 12,000 l/h. An additional nitrogen or carbon dioxide swirl flow was used. The absorbed microwave power was up to 5000 W. Our experiments show that MPSs presented in this paper have a high potential for hydrogen production via hydrocarbon conversion. Copyright ª 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. 1. Introduction Development of plasma sources based on the microwave technique are of increasing interest from industrial point of view. Microwave sustained plasma has been widely investi- gated [1e5] and found practical applications in various fields, like gas purification [6], decomposition of gaseous pollutants [7], sterilization, food preservation, living cells treatment [8], surface modification [9,10] etc. Recently, one of the promising application is using microwave plasma for hydrogen produc- tion [11e13]. Hydrogen is more and more attractive as an efficient and environmental friendly source of energy. It is considered as a promising fuel of the future. According to a European roadmap for hydrogen and fuel cells published by European Commission in “Hydrogen Energy and Fuel Cells: A vision of our future” [14] in the medium to long term (it means beyond 2020) the main attention should be paid for developing and implementing systems for hydrogen production from renewable electricity and biomass. At the same time the research and development of other carbon-free hydrogen sources, such as solar thermal and advanced nuclear should be continued. Hydrogen can be produced from different kind of feedstock like fossil fuels, water, biomass. Recently, in industry methane or natural gas reforming is widely used to obtain hydrogen or synthesis gas, which are utilized, for example as source ma- terials for the production of raw chemicals (e.g. methanol and ammonia), as well as hydrogenation agents in oil refinery and reducing gases in steel industry. There are a few different methane based methods of hydrogen production like: * Corresponding author. Tel.: þ48 58 6995244. E-mail addresses: mj@imp.gda.pl (M. Jasi  nski), dczylkowski@imp.gda.pl (D. Czylkowski). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 38 (2013) 11473 e11483 0360-3199/$ e see front matter Copyright ª 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijhydene.2013.05.105