Degradation of toluene vapor using vacuum ultraviolet photolytic a way to reduce air pollution

THAI NGUYEN UNIVERSITY UNIVERSITY OF AGRICULTURE AND FORESTRY LE NGOC KHANH DEGRADATION OF TOLUENE VAPOR USING VACUUM ULTRAVIOLET: A WAY TO REDUCE AIR POLLUTION BACHELOR THESIS Study Mode: Full-time Major: Environmental Science and Management Faculty: Advanced Education Programs Office Batch: 2014 - 2018 Thai Nguyen, 25/09/2018 ACKNOWLEDGEMENT I would like firstly to emphasize the sincere appreciation to lecturers in the Advance Education Program as well as lecturers in Thai Nguyen University of Agriculture and Forestry, who have lectured me profound knowledge not only for my subjects but also for my soft skills and gave me a chance to my thesis abroad In addiction, I would like to thank all supports and help from Department of Environmental Engineering, Falculty of Engineering, King Mongkut’s University Technology of Thonbori for the time I conducted my research in Thailand It is my pleasure to work with a profound supervisor- Professor Prapat Pongkiakul, who always helped me any time He also gave me the best conditions, supported all materials for my research and discussed any problems I got whnenever I did experiments in his Environmental Engineering Laboratory I would like to give my special thanks to Dr Profesor Nguyen Hung Quang, who always supported and cheered me up the whole time I worked oversea He also helps me a lot in spending much tim checking my thesis report Finally, I would like to express my gratitude to my family and friends, who always beside me all the time Their help support and encouragements created the pump leading me to my success Sincerely Khanh Le Ngoc Khanh i TABLE OF CONTENT ACKNOWLEDGEMENT i TABLE OF CONTENT ii LIST OF FIGURES iv LIST OF TABLES v LIST OF ABBREVIATIONS vi DOCUMENTATION PAGE WITH ABSTRACT vii PART I INTRODUCTION 1.1 Research rationale 1.2 Reasearch’s Objectives 1.3 Research questions and hypothesis 1.4 Limitations 1.5 Definitions 1.5.1 Toluene .3 1.5.2 Standard of toluene PART II LITERATURE REVIEW PART III METHOD 10 3.1 Materials 10 3.2 Method .10 3.2.1 Experiment setup .10 3.2.2 Calculate flow rate of gas based on a retention time 11 3.2.3 Experimental setup 13 PART VI RESULT AND DISSCUSION 14 4.1 Result 14 4.1.1 Reduction of outlet concentration of 200 ppm and C/Co(%) 14 4.1.2 Reduction of outlet concentration of 150 ppm and C/Co(%) 16 4.1.3 Reduction of outlet concentration of 100 ppm and C/Co(%) 19 4.2 Disscusion 21 4.2.1 Reduction of outlet concentration 21 4.2.1.1 Inlet concentration of 200 ppm 21 ii 4.2.1.2 Inlet concentration of 150 ppm 22 4.2.1.3 Inlet concentration of 100 ppm 23 4.3 Removal efficiecy 23 4.3.1 C/Co efficiency at 200 ppm inlet concentration 23 4.3.2 C/Co efficiency at 150 ppm inlet concentration .24 4.3.3 C/Co efficiency at 100 ppm inlet concentration 25 4.3.4 Comparison of removal efficiency of toluene .25 PART V CONCLUSION .27 REFERENCE 28 PART VI APPENDICES .32 iii LIST OF FIGURES Figure 1.1 Chemical properties of toluene Figure 1.2 Schematic diagram of experiment setup 11 Figure 1.3 Size of reactor 12 Figure 1.4 Changes of outlet toluene concentration (inlet concentration at 200 ppm) after apply VUV radiation 22 Figure 1.5 Changes of outlet toluene concentration (inlet concentration at 150 ppm) after apply VUV radiation 22 Figure 1.6 Changes of outlet toluene concentration (inlet concentration at 100 ppm) after apply VUV radiation 23 Figure 1.7 Changes of removal efficiency at the inlet concentration of 200 ppm 24 Figure 1.8 Changes of removal efficiency at the inlet concentration of 150 ppm 24 Figure 1.9 Changes of removal efficiency at the inlet concentration of 100 ppm 25 Figure 1.10 Comparison of toluene removal efficiency for the inlet concentrations of 100, 150, and 200 ppm 26 iv LIST OF TABLES Table 1.1 Physical properties of toluene Table 1.2 Occupational Exposure Limits of toluene from USA Table 1.3 Maximum allowable concentration of some hazardous substances in ambient air in Viet Nam (Legal 2006) Table 1.4 List of materials used in the experiment 10 Table 1.5 Calculate the flow rate based on retention time .12 Table 1.6 Degradation and removal efficiency of outlet concentration of 200 ppm 14 Table 1.7 Degradation and removal efficiency of outlet concentration of 150 ppm 17 Table 1.8 Degradation and removal efficiency of outlet concentration of 100 ppm 19 v LIST OF ABBREVIATIONS VUV Vacuum Ultraviolet VOC Volatile organic compounds CNS Central nervous system PID Photoionization detection OSHA PEL The Occupational Safety and Health Administration STEL Short-term exposure limit NIOSH IDLH The National Institute for Occupational Safety and Health immediately dangerous to life or health ACGIH TLV American Conference of Governmental Industrial Hygienists threshold limit value AIHA ERPG-2 American Industrial Hygiene Association emergency response planning guideline WHO World Health Organization TWA Time weighted average PEL Permissible exposure limit vi DOCUMENTATION PAGE WITH ABSTRACT Thai Nguyen University of Agriculture and Forestry Degree Program Bachelor of Environmental Science and Management Student name Le Ngoc Khanh Student ID DTN1454290015 Thesis Title Degradation of Toluene Vapor using Vacuum Ultraviolet Photolytic : A Way to Reduce Air Pollution Supervisor (s) Nguyen Hung Quang Supervisor’s signature (s) Abstract Vacuum ultraviolet is a simple way to destruct volatile organic compounds (VOCs) In this paper, we are experiment the concentration of toluene during 30 minutes open VUV lamp Results indicate that the toluene removal efficiency is only 11 % in the VUV process This process is depend on the influence concentration of toluene, the concentration of toluene increased, removal efficiency decreased and the concentration decreased, removal efficiency increased Keywords Toluene vapor VUV radiation Flow rate Removal efficiency Toluene concentration VUV Number of Pages 42 Date of Submission: 25/09/2018 vii PART I INTRODUCTION 1.1 Research rationale Organic compounds are chemicals that contain carbon and are usually found in all living things Volatile organic compounds, sometimes referred to as VOCs, are organic compounds that easily become vapors or gases (high vapor pressure) Most of VOCs has a low boiling point of less than 15 C However, some VOCs may also contains some other substitutes such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur or nitrogen, which may cause more harmful effects to human VOCs are commonly released from burning fuel, such as gasoline, wood, coal, or natural gas They are also emitted from oil and gas fields and diesel exhaust They are also released from solvents, paints, glues, and other products that are used and stored at home and at work A number of petrochemical industry and some other types of industry also produces or uses many types of VOCs in their processes Loss of those chemicals into air has been investigated more than 500 tons per year from industrial sector in Thailand Exposure with multi VOCs may associate with various syndromes, such as fatigue, nausea, impaired vigilance, confusion, drowsiness, irritant-induced asthma, and some respiratory symptoms High exposure of VOCs at short period may cause various actual effects, whereas many species of VOCs has a close-link to be a major cause of cancer (called “carcinogen”) For example, formaldehyde and benzene are considered by many authorities to be probable human carcinogens Nowadays, there are totally conventional techniques to control VOCs emission from various types of industry, which are absorption, adsorption, incineration/oxidation, bio-filtration, and condensation Each technique has their own advantages and limitations Absorption commonly limits on VOC gas solubility in the selected liquid used in thes system Smaller liquid droplet may increase the solubility of the gas Adsorption is a promising technology, which always provides high removal efficiency, but the cost of operation and dispose is also high Incineration/oxidation is generally applied for VOCs emission at high concentration, which high enough to be self-ignition Lower concentration may also increase operation costs due to additional co-fuel in the system Bio-filtration is a cheapest technology, which has low investment and operation cost The microorganism including bacteria and fungi are immobilized in the biofilm and degrade the pollutant in the system Due to the system rely mainly on microbial growth, bio-clogging may be found for sometime The condensation is one of the recycling technologies to condense the gaseous pollutants (VOC) to become liquid under high pressure and/or low temperature However, pollutant concentration should be high for cost effectiveness Vacuum Ultraviolet, or VUV, (has wavelengths shorter than 200 nm) are strongly absorbed by molecular oxygen in the air Longer wavelengths of about 150–200 nm can propagate through nitrogen, which is highly active for VOCs oxidation A VUV lamp emits UV light at a wavelength of 185 nm and generated energetic photons that can activate oxygen and water vapor to produce numerous reactive species such as O(D), O(P), hydroxyl radicals (OH) and Ozone VUV has been used to destruct various VOCs including benzene, toluene Nevertheless, its application is greatly limited by the formation of O3 byproduct and low degradation capacity and mineralization rate for VOC destruction In this study, VUV was applied to remove toluene vapor from synthesis gas, as a case study Oxidation of VOCs was performed under VUV radiation in a continuous flow reactor 1.2 Reasearch’s Objectives To assess the efficiency of toluene removal using VUV radiation in a continuous flow reactor 1.3 Research questions and hypothesis A breach-scale experiment was set up at the Department of Environmental Engineering, King Mongkut’s University of Technology Thonburi (KMUTT) A 3-L stainless reactor was selected in the study Toluene vapor was simulated using a toluene generator developed under this study A continuous flow experiment was The removal efficiency was assessed using measurement at inlet and outlet of the reactor Turn lamp on 14 100 15 100 16 100 17 100 18 99.9 0.999 19 100 20 100 21 100 22 100 23 100 24 100 25 100 26 100 27 100 28 100 29 100 30 100 the 31 100 32 99.8 0.998 33 99.8 0.998 34 97.8 0.978 35 98.3 0.983 36 98.1 0.981 37 97.6 0.976 38 97 0.97 39 96.5 0.965 40 96.4 0.964 41 96.2 0.962 42 95.6 0.956 43 94.8 0.948 20 44 94 0.94 45 93.6 0.936 46 92.8 0.928 47 92.5 0.925 48 92.1 0.921 49 92 0.92 50 91.5 0.915 51 91.2 0.912 52 90.4 0.904 53 90.5 0.905 54 91.1 0.911 55 91.2 0.912 56 90.8 0.908 57 90.7 0.907 58 91 0.91 59 90.2 0.902 60 89 0.89 As the table 1.8 shown, toulene concentration fell down approximately 11 ppm after 30 minutes when VUV lamp was turned on With this result, removal efficiency were calculated by around 11%, it is reasonable but the removal efficiency is lower than the other literature 4.2 Disscusion 4.2.1 Reduction of outlet concentration 4.2.1.1 Inlet concentration of 200 ppm Figure 1.4 shows the reduction of toluene concentration with the inlet concentration of 200 ppm after turn on the VUV lamp Concentration was gradually reduced from 200 to 197 ppm at the 30th minute – 34th minute (1-4 after apply VUV radiation) The outlet concentrations fluctuated around 197 ppm until the 40th 21 minute Outlet concentration rapidly dropped again to 191.2 ppm at the 50th minute and slowly reduced until the 60th minute at the concentration of 191.1 ppm Figure 1.4 Changes of outlet toluene concentration (inlet concentration at 200 ppm) after apply VUV radiation 4.2.1.2 Inlet concentration of 150 ppm After turn on the VUV lamp, the inlet concentration of toluene reduced to 147 ppm and started to fluctuated at the 35th minute at an average concentration of 147.7 ppm The outlet concentrations were dramatically decresed to 137.2 at the 53rd minute Then, it slowly changed to 137 ppm at the 60th minute Figure 1.5 Changes of outlet toluene concentration (inlet concentration at 150 ppm) after apply VUV radiation 22 4.2.1.3 Inlet concentration of 100 ppm Figure 1.6 showed that the outlet concentrations reduced from 100 to 97.8 ppm after minutes of VUV lamp radiation application Concentration fluctuated around 97.6 ppm from the 34th to 37th minutes Outlet concentration of toluene decreased quikly again to 90.5 ppm at the 52nd minute and slowly changed to 89 ppm at the 60th minute Figure 1.6 Changes of outlet toluene concentration (inlet concentration at 100 ppm) after apply VUV radiation 4.3 Removal efficiecy 4.3.1 C/C₀ efficiency at 200 ppm inlet concentration Figure 1.7 shows the changes of removal efficiency of toluene over the time at the inlet concentration of 100 ppm The final efficiency was (1-0.95)*100% = 5% after 30 minutes of VUV radiation 23 Figure 1.7 Changes of removal efficiency at the inlet concentration of 200 ppm 4.3.2 C/C₀ efficiency at 150 ppm inlet concentration Concentration of toluene tended to reduce after 30 minutes, the maximum efficiency for the inlet concentration of 150 ppm was (1-0.91)*100%= 9% Figure 1.8 Changes of removal efficiency at the inlet concentration of 150 ppm 24 4.3.3 C/C₀ efficiency at 100 ppm inlet concentration The highest toluene removal efficiency was (1-0.89)*100%= 11% for the inlet concentration of 100 ppm Figure 1.9 showed the changes of removal efficiency at the inlet concentration of 100 ppm Figure 1.9 Changes of removal efficiency at the inlet concentration of 100 ppm 4.3.4 Comparison of removal efficiency of toluene After comparison of toluene removal efficiency for all experiments, the overall toluene reduction was low, 11% (100 ppm), 9% (150 ppm), and 5% (200 ppm), as compared to other literatures This might be because of the reactor design In general, the VUV radiation has highest power at around 1-2 mm in layer from the lamp Turbulence of gas in the reactor is also important However, the results found that the removal efficiencies was also varied according to the inlet concentrations Other ambient factors were also significant, such as gas moisture, and temperature Higher moisture can increase photolysis rate of removal Figure 1.10 shows the comparison of toluene removal efficiency for the inlet concentrations of 100, 150, and 200 ppm 25 Figure 1.10 Comparison of toluene removal efficiency for the inlet concentrations of 100, 150, and 200 ppm 26 PART V CONCLUSION Base on the results, VOCs have been removed under VUV irradiation in a continuous flow reactor with highest 11% removal efficiency of toluene vapor.Flow rate is the most important factor affect to removal efficiency of toluene This solution may apply to reduce volatile organic compounds in industrial where it is eliminated It is also the application in the near future’s technology There are some factor that we need to focus in this expiriment such as humidities, reactor design, condition of the lamp Reactor design should be close tight with system of expiriement The lamp with high quality 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of Federal Regulations 29 CFR 1910.1000 31 PART VI APPENDICES 32 33 34 ... Degradation of Toluene Vapor using Vacuum Ultraviolet Photolytic : A Way to Reduce Air Pollution Supervisor (s) Nguyen Hung Quang Supervisor’s signature (s) Abstract Vacuum ultraviolet is a simple... controll flow rate of gas Pipe meters Lead the gas and toluene Rotameter Measure the flow rate of gas Box mix gas and toluene Toluene bottle lit contain toluene Reactor Generrate toluene VUV lamp VOCs... due to the fresh air passing through, part of toluene liquid in the bottle is vaporized Generated highconcentration toluene vapor was mixed with a fresh air again in a mixing box to dilute toluene