3552 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 46, NO. 10, OCTOBER 2018

Study of Exhaust Air Treatment From a ShipBuilding Factory Painting Facility Using

Pulse Plasma TechnologyHee-Sung Jin, Seung-Ho Song , Chan-Gi Cho, Su-Mi Park, and Hong-Je Ryoo , Member, IEEE

Abstract— Ship building companies are exposed to increasinglystrict regulations on exhaust air from painting facilities, whichcurrent exhaust air treatment methods cannot adequately meet.We propose the use of a plasma system using a pulsed-powersupply, which we constructed and tested at the painting facilityof a ship building factory. Through gas chromatography andfacility efficiency analysis, we found flexibility in design of theplasma system. We demonstrate the efficiency and safety of ourplasma system, and emphasize the importance of posttreatmentfacilities for the secondary pollutant treatment.

Index Terms— Plasma reactor, pulsed-power supply, shipbuilding painting factory, volatile organic compound (VOC)treatment.

I. INTRODUCTION

IN THE ship building process, painting is essential inorder to prevent corrosion. As a huge amount of paint is

used, large volumes of volatile organic compounds (VOCs),pollutants harmful to human health, are released [1], [2].

In response to this problem, the Korean government hastightened regulations on VOCs in exhaust air of large paintingfacilities (>50 000 m3), such as ship building factories [3].However, there is currently no adequate solution actuallyapplied to large painting facilities; current methods such ascarbon absorption or regenerative thermal oxidizer (RTO) [4]demand either high operation or installation costs, or largeinstallation areas, and release secondary pollutants. In partic-ular, RTO systems installed at some ship building factorieshave high energy consumption, risk of explosion at high VOCconcentrations, and require long periods for the preheatingprocess, in contrast to short treatment periods (e.g., 4 hper day) [5]. In order to address these issues, plasma tech-nology is recommended, and has been studied for treatmentof various gaseous materials [6]–[8]. Plasma technology doesnot require preheating and so has low operation costs, and is

Manuscript received December 6, 2017; revised March 15, 2018; acceptedApril 7, 2018. Date of publication May 8, 2018; date of current versionOctober 9, 2018. This work was supported in part by the National ResearchFoundation of Korea (NRF) Grant funded by the Korea Government (MSIP)under Grant NRF-2017R1A2B3004855 and in part by the Human ResourcesProgram in Energy Technology of the Korea Institute of Energy TechnologyEvaluation and Planning, Ministry of Trade, Industry and Energy, Republic ofKorea, under Grant 20164030201100. The review of this paper was arrangedby Senior Editor W. Jiang. (Corresponding author: Hong-Je Ryoo.)

The authors are with the Department of Energy Systems Engineering,Chung-Ang University, Seoul 06974, South Korea (e-mail: hjryoo@cau.ac.kr).

Color versions of one or more of the figures in this paper are availableonline at http://ieeexplore.ieee.org.

Digital Object Identifier 10.1109/TPS.2018.2829494

Fig. 1. Structure of test facility.

Fig. 2. Plasma reactor structure.

environmentally friendly in that it dissolves pollutants. In thispaper, we show how pulse plasma technology can handlethe problems of current treatment methods and how it caneffectively treat pollutants from the exhaust air of ship buildingfactories.

II. SUGGESTION OF PLASMA FACILITY FOR

EXHAUST AIR TREATMENT

Fig. 1 shows the structure of our plasma treatment facility.Exhaust air from the painting process passes through thefollowing apparatus: suction fan, first plasma reactor, secondplasma reactor, and posttreatment catalyst facility, after whichthe final material is produced.

A. Plasma ReactorThe basic structure of the plasma reactor is depicted

in Fig. 2. It has electrode plates with multiple needles andholes. High-voltage input between the high voltage and earthelectrodes creates a cone-shape plasma between the plates.If 100% of the exhaust air can be forced to flowthrough theplasma area, then efficiency is maximized.

Fig. 3 shows the actual shape of the needle plate moduleof the plasma reactor. One plate module has approximately

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JIN et al.: STUDY OF EXHAUST AIR TREATMENT FROM SHIP BUILDING FACTORY PAINTING FACILITY 3553

Fig. 3. Constructed plasma reactor.

Fig. 4. Pulsed-power supply.

TABLE I

SPECIFICATION OF PLASMA POWER SUPPLY OUTPUT

900 needles. We designed the needle plate module in a detach-able “drawer” structure for easy maintenance. One plasmareactor set consists of five stories of plate modules, as shownin Fig. 3. At the bottom of the reactor, there is a pretreatmentfilter for removing external particles.

B. Pulsed-Power SupplyFig. 4 shows the constructed pulsed-power supply for

plasma reactor operation. The pulsed-power supply used inthis paper is more efficient than a sine wave power supply.It has the ability to make quick repeats and to reach a highvoltage within a short time frame, leading to high energydensity. It can effectively decompose most gaseous materials(greater than 10 eV), retaining them postreaction with stableplasma discharge [9].

Table I provides the output specification of the pulsed-powersupply. Output voltage is at maximum 40 kV, the output waveshape is + pulse, pulsewidth is 1–5 µs, pulse repeat rate is300 Hz–3 kHz, and rising time is 500 ns. The pulsed-powersupply switch uses insulated-gate bipolar transistor devicesconnected in series, enabling a maximum output of 40 kV.Input voltage is three-phase 380 V, and power consumption is10 kW maximum.

Fig. 5. Secondary catalytic reactor.

Fig. 6. Plasma discharge from the needle-type electrode of the reactor.

C. Posttreatment Catalytic ReactorFig. 5 shows the secondary catalytic reactor for the decom-

position of ozone (O3), a by-product of the plasma reaction.The following chemical reaction shows how ozone reacts withC and H molecules by catalyst and changes into CO2, H2O,and O2 [10]:

C6H12 + 18O3 = 6CO2 + 6H2O + 18O2.

The main materials comprising the ozone decompo-sition catalyst include manganese (MNO2) and oxidizedcopper (CuO). We put pellet form catalyst [Fig. 5 (left)] intothe reactor [Fig. 5 (right)]. We also put a heating cable insidethe reactor to activate the catalytic reaction.

III. TEST RESULT AND REVIEW

A. Plasma Reactor DischargeFig. 6 shows a photograph of the plasma discharge of the

needle-type electrode, and Fig. 7 shows a photograph of theplasma discharge of the whole reactor. When the needle-typeelectrode is exposed to high voltage with the plate grounded,a cone-shape plasma discharge is observed from the center ofthe needle-type electrode to the grounded electrode.

B. Measurement of Pulsed-Power Supply OutputFig. 8 shows the output wave from the plasma reactor and

pulsed-power supply using an oscilloscope with a high-voltageprobe and current sensor. The measurements recorded were:output pulse voltage 25 kV, output pulse current 196 A, pulserising time 227 ns, and pulse repeat rate 1500 Hz. The inputpower consumption was 3 kW/h.

C. Practical ApplicationFig. 9 shows installation of our system (based on the test

facility structure shown in Fig. 1) at the painting facility of anoperational ship building company.

3554 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 46, NO. 10, OCTOBER 2018

Fig. 7. Actual plasma discharge from the whole reactor.

Fig. 8. Pulsed-power supply and output wave.

Fig. 9. Installation at operational ship building facility.

Air flow, measured with a hot wire anemometer, was1.7 m/s at a 300-mm diameter duct, and air volume wasabout 432 cm/H. Gases were measured using a Gastec tube(toluene 122 L) and gas chromatography (GC) analysis afterair sampling.

Fig. 10 shows the pictures of process for gas treatmentand air sampling and Fig. 11 comparisons of collected com-ponents before and after treatment from GC/mass selectivedetector (MSD).

First, in order to confirm trends, we used a toluene Gastectube (one of the most representative materials for VOCs) tomeasure efficiency. Second, we sampled air with Tedlar bags,absorbed 2-L air on a Tenax-TA coated tube, and then analyzed

Fig. 10. Gas measurement and air sampling.

Fig. 11. Measurements from GC/MSD.

TABLE II

MEASUREMENTS FROM GASTEC TUBES

it with GC/MSD. As described in Table II, the results with theGastec tube were: 1) a decrease of 50% with 20-ppm inputconcentration after the first plasma reactor and 2) a decreaseof 85% after the second plasma reactor and of 90% afterthe postcatalyst facility. Measurements with GC/MSD were:1) a decrease of 30% with 10 802 ppb after the first plasmareactor and 2) a decrease of 71% after the second plasmareactor and of 93% after the postcatalyst facility. As shown

JIN et al.: STUDY OF EXHAUST AIR TREATMENT FROM SHIP BUILDING FACTORY PAINTING FACILITY 3555

TABLE III

MEASUREMENTS FROM GC/MSD

in Table III, low-level fat acid materials such as butyric andpropionic acids were created as by-products that decreased inconcentration through the period of plasma reactor treatmentand the postcatalyst facility. Harmful materials such as ben-zene were not detected.

IV. RESULTS

In this paper, we used a plasma reactor with a pulse-powersupply to treat exhaust air from a painting facility of a shipbuilding company. We assessed treatment efficiency in terms ofthe presence of harmful materials and obtained the followingresults.

1) As the plasma reactor treatment increased, efficiencyincreased, proving that target efficiency can be obtainedwith an increased number of plasma reactors, whichgives flexibility in facility design.

2) GC analysis showed a 92% decrease in harmful mate-rials following the final treatment, proving that thetreatment has sufficient efficiency.

3) It is important and necessary to include a posttreat-ment process after plasma reactor use in order to treatby-products. After our posttreatment process, there weresmall amounts of low-level fatty acid materials, withoutharmful materials such as benzene.

4) Based on an input power consumption of 3 kW/h,we calculate that the electric cost of a plasma reac-tor for a real ship building company would beabout 760 000 KRW per facility (70 kW/h, 6 h/day,80 KRW/kWh, and 20 days/month). This shows that theoperation cost of the plasma method is much lower thanthat of the RTO method.

5) Finally, the working conditions of individual paintingfacilities in ship building companies differ. In order to

apply the plasma method to a real site, it is important tostudy the conditions and factors such as concentrationlevels, exhaust period, temperature, humidity, pretreat-ment facilities (blocking paint particles), posttreatmentfacilities, operation and maintenance, convenience ofoperation, and safety.

REFERENCES

[1] HAPs (Hazardous Air Pollutants) Fugitive Emission Facility Manage-ment System, Korea Ministry Environ., Dec. 2016.

[2] The Literature of Indoor VOCs Characterization and Control Method-ology, Korea Ministry Environ., Apr. 2001.

[3] Korean’s, “Clean air conservation act,” Article 38-2 (Notification ofinstallation of fugitive emission facility), Jan. 2017. [Online]. Available:http://www.law.go.kr/??/???????/

[4] S. H. Park, “Instrumentation technology,” Korea Environmental Technol-ogy Development Corporation Control technology of odor and volatileorganic compounds (VOCs), Korea National Environmental Informa-tion Center (KONETIC), Dec. 2010. [Online]. Available: http://procon.co.kr/pdf/2011%204/%EC%97%B0%EC%9E%AC_201104_02.pdf

[5] A Study on Reduction of Hazardous Air Pollutant Fugitive Emissions inShipyard, Korean Environ. Sci. Soc., Apr. 2014.

[6] Y. H. Song et al., “Characteristics of non-thermal plasma processes forair pollution control,” J. Korean Soc. Atmos. Environ., vol. 16, no. 3,pp. 247–256, Jun. 2000.

[7] K. S. Jeong and M. S. Hong, “A study on the removal of NOx usingsilent discharge plasma reactor,” J. KSEE, vol. 18, no. 7, pp. 899–907,Apr. 1996.

[8] Y. S. Choi, W. N. Lee, and Y. H. Song, “NO removal characteristics ofa barrier discharge type reactor using non-thermal plasma,” J. KSME,vol. 1, no. 2, pp. 705–710, Jan. 1999.

[9] Y. H. Song, “Atmospheric pressure plasma applications to treat off-gases from semiconductor manufacturing,” J. Korean Soc. Precis. Eng.,vol. 19, no. 8, pp. 34–37, 2002.

[10] H. Einaga and S. Futamura, “Oxidation behavior of cyclohexane onalumina-supported manganese oxides with ozone,” Appl. Catal. B,Environ., vol. 60, nos. 1–2, pp. 49–55, Sep. 2005.

Hee-Sung Jin received the B.S. degree in infor-mation and communication engineering from DongYang Mirae University, Seoul, South Korea, in 2008.He is currently pursuing the M.S. degree withthe Department of Energy Engineering, Chung-AngUniversity, Seoul.

In 2008, he joined the Sudo Premium Engi-neering Co., Ltd., Seoul, where he is currently aResearch and Development Team Manager. His cur-rent research interests include gas processing systemusing plasma generators.

Seung-Ho Song received the B.S. degree in electri-cal engineering from Kwangwoon University, Seoul,South Korea, in 2016. He is currently pursuing theM.S. and Ph.D. degrees with the Department ofEnergy Engineering, Chung-Ang University, Seoul.

His current research interests include soft-switchedresonant converter applications and high-voltagepulsed-power supply systems.

Chan-Gi Cho received the B.S. degree in informa-tion display engineering from Kyung Hee University,Seoul, South Korea, in 2016, and the M.S. degree inenergy system from Chung-Ang University, Seoul,in 2018, where he is currently pursuing the Ph.D.degree with the Department of Energy System Engi-neering.

His current research interests include resonantconverters and high-voltage pulsed-power systems.

3556 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 46, NO. 10, OCTOBER 2018

Su-Mi Park received the B.S. degree in energysystems engineering from Chung-Ang University,Seoul, South Korea, in 2017, where she is currentlypursuing the M.S. degree with the Department ofEnergy Engineering.

Hong-Je Ryoo (M’17) received the B.S., M.S.,and Ph.D. degrees in electrical engineering fromSungKyunkwan University, Seoul, South Korea, in1991, 1995, and 2001, respectively.

From 2004 to 2005, he was a Visiting Scholarwith the Wisconsin Electric Machines and PowerElectronics Consortium, University of Wisconsin–Madison, Madison, WI, USA. From 1996 to 2015,he was a Principal Research Engineer with theElectric Propulsion Research Division, Korea Elec-trotechnology Research Institute, Changwon, South

Korea, where he was a Leader with the Pulsed Power World Class Laboratory,the Director of the Electric Propulsion Research Center. From 2005 to 2015,he was a Professor with the Department of Energy Conversion Technology,University of Science and Technology, Daejeon, South Korea. In 2015,he joined the School of Energy Systems Engineering, Chung-Ang University,Seoul, where he is currently an Associate Professor. His current researchinterests include pulsed-power systems and their applications, as well as high-power and high-voltage conversions.

Dr. Ryoo is a member of the Korean Institute of Power Electronics and aSenior Member of the Korean Institute of Electrical Engineers. He is alsothe Vice President of the Korean Institute of Illuminations and ElectricalInstallation Engineers.