Sains Malaysiana 39(6)(2010): 981–987

 

Discharge Based Processing Systems for Nitric Oxide Remediation

(Sistem Pemprosesan Berasaskan Nyahcas untuk Pemulihan Nitrik Oksida)

 

S.A. Hashim & C.S. Wong*

Plasma Research Laboratory, Physics Department, Faculty of Science

University of Malaya, 50603 Kuala Lumpur, Malaysia

 

M.R. Abas

Department of Chemistry, Faculty of Science

University of Malaya, 50603 Kuala Lumpur, Malaysia

 

K.Z. Hj. Dahlan

Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor, Malaysia

 

Diserahkan: 21 Oktober 2009 / Diterima: 4 Mac 2010

 

ABSTRACT

 

An electron beam (EB) flue gas test rig and a dielectric barrier discharge (DBD) reactor were tested for the removal of nitric oxide (NO) from gas stream in separate experiments. In both systems, energised electrons were used to produce radicals that reacted with the pollutants. The EB system was a laboratory scale test rig used to treat emission from a diesel run generator. At 1.0 MeV and 10 mA more than 90% NO removal from flue gases flowing at 120 Nm3/h can be achieved. For higher removal percentage, higher beam current was required. In a related effort, a table top, two tubes DBD reactor was used to process bottled gases containing 106 ppm NO. Total removal (>99%) was achieved when the inlet gas contained only NO and N2. Additional SO2 in the in let gas stream lowered the removal rate but was overcame by scaling up the system to 10 DBD tubes. The system was operated with input AC voltage of 35 kV peak to peak. In the EB treatment system, the amount of NO2 increased at high beam current, showing that the NO was also oxidised in the process. Whereas in the DBD reactor, the amount of NO2 remained insignificant throughout the process. This leads to the conclusion that the DBD reactor is capable of producing total removal of NO. This is highly desirable as post treatment will not be necessary.

 

Keywords: Dielectric barrier discharge; electron beam; nitric oxide

 

ABSTRAK

 

Kajian terhadap penghapusan nitrik oksida (NO) menggunakan teknik alur elektron (EB) dan nyahcas dielektrik berpenghadang telah dijalankan secara berasingan. Kedua-dua sistem ini menghasilkan elektron bertenaga tinggi untuk menghasilkan radikal yang bertindak balas dengan bahan pencemar. Sistem alur electron tersebut adalah binaan skala makmal yang digunakan untuk merawat gas tercemar yang terhasil daripada sebuah generator disel. Pada 1.0 MeV dan 10 mA, lebih 90% NO berupaya dinyahkan dari gas tercemar yang mengalir dengan kadar 120 Nm3/j. Arus bim yang lebih tinggi diperlukan untuk mencapai tahap penghapusan yang lebih tinggi. Dalam kajian lain yang berkaitan, sebuah reaktor 2 tiub DBD digunakan untuk memproses gas dari selinder yang mengandungi NO dengan kepekatan 106 ppm. Penghapusan sepenuhnya (>99%) telah dicapai apabila gas masukan mengandungi hanya NO dan N2. SO2 tambahan pada gas masukan menyebabkan kadar pengenyahanan susut tetapi ini dapat diatasi dengan menambah bilangan tiub kepada 10. Sistem ini beroperasi pada voltan AC 35 kV puncak ke puncak. Bagi sistem menggunakan EB, didapati kepekatan gas nitrik dioksida (NO2) meningkat pada arus bim tinggi, menandakan NO telah teroksida semasa proses berlaku. Di dalam sistem DBD bagaimanapun, kepekatan NO2 tidak menunjukkan peningkatan yang ketara sepanjang proses. Ini menunjukkan bahawa sistem DBD tersebut mampu menyahkan NO secara menyeluruh tanpa keperluan rawatan susulan.

 

Kata kunci: Alur electron; nitrik oksida; nyahcas dielektrik berpenghadang

 

RUJUKAN

 

Calinescu, I., Ighigeanu, D., Martin, D. & Bulearca, A. 2008. Electron Beam Technologies for Reducing SO2 and NOx Emissions from Thermal Power Plants, WEC Regional Energy Forum – Foren 15-19 June, Neptun.

Chen, Z. & Mathur, V.K. 2002. Nonthermal plasma for gaseous pollution control. Ind. Eng. Chem. 41: 2082-2089.

Cheng, M.B., Krushner, M.J. & Rood, M.J. 1992. Gas phase removal of no from gas streams via dielectric barrier discharges. Environ. Sci. Technol. 26(4): 777-781.

Chmielewski, A.G., Iller, E. & Frank, N.W. 1997. Technical and Economical Aspects of E-B Installations for Treatment of Flue Gases from Power Plant. Proceeding of International Symposium on Radiation Technology for Conservation of the Environment. 8-12 September. Zakopane.

DOC (Department of Environment Malaysia). 2007. Annual Report 2007. Putrajaya.

Gentile, A.G. & Kushner, M.J. 1995. Reaction chemistry and optimization of plasma remediation of NxOy from gas streams, J. Appl. Phys. 78(3): 2074-2085.

Harling, A.M., Glover, D.J., Whitehead, J.C. & Zhang, K. 2008. Industrial scale destruction of environmental pollutans using a novel plasma rector, Ind. Eng. Chem. 47: 5856-5860.

Hashim, S.A., Dahlan, K. & Ghazali, Z. 2001. Utilisation of electron beam technology for purification of flue gases on the application of electricity power supply industry. Report on Test and Commissioning of Flue Gases Purification System. PART II: Commissioning of Test Rig (Period: May-October): Malaysian Nuclear Agency, Internal publication.

Hashim, S.A., Wong, C.S., Abas, M.R. & Dahlan, K.Z. 2007. Feasibility study on the removal of nitric oxide (NO) in gas phase using dielectric barrier discharge reactor. Malaysian Journal of Science 26(2): 111-116.

Kogelschatz, U., Eliasson, B. & Egli, W. 1999. From ozone generators to flat television screens: history and future potential of dielectric-barrier discharges. Pure Appl. Chem. 71(10): 1819-1828.

Mok, Y.S. 2005. Application of dielectric barrier discharge to selective catalytic reduction of nitrogen oxides. XXVIIth ICPIG, Eindhoven, the Netherlands, 18-22 July.

Namba, H. 1992. Electron beam treatment of coal fired flue gas, advanced nuclear energy research, global environment and nuclear energy. Proc. 3rd Int. Symp. Mito, Japan, Japan Atomic Energy Research Institute, Takasaki.

Paur, H-R. & Schikarski, W. 1992. Electron beam induced purification of industrial emissions. In: Proceeding of an International Symposium on Applications of Isotopes and Radiation In Conservation of the Environment, Karlsruhe 9-13 March.

Rajeswari, K.R., Noorsaadah, A.R. & Wong, C.S. 2001. Effect of temperature on the ozonation of textile waste effluent, Color. Technol. 117: 95-97.

Xu, X. 2001. Dielectric barrier discharge: properties and applications. Thin Solid Films 390: 237-242.

 

*Pengarang untuk surat-menyurat; email: cswong@um.edu.my

 

 

 

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