Mercury control technology by chemically treated activated carbon using simulated flue gas | |
| Author | Joshi, Umid Man |
| Call Number | AIT Thesis no.EV-03-24 |
| Subject(s) | Flue gases Mercury Refuse and refuse disposal |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-03-24 |
| Abstract | The issue of mercmy emission from incinerators has been getting increasing attention due to its unique characteristics, such as high volatility, tendency to bio-accumulate and toxic properties. Till this date, there are no state of the art treatment methods available for the mercury control in flue gas. This study aimed at developing a new sorbent that has significant mercury adsorption capacity. In this study, two chemically impregnated activated carbons - (i) chlorine and (ii) iodine were used. Hydrochloric acid (HCl) and potassium iodine (KI) were used to impregnate chlorine and iodine respectively. Preliminary tests were done to determine the optimum concentration of the impregnation solution and optimum amounts of activated carbons. Then detailed experiments were done to test the removal of elemental mercury. Granular activated carbons of size 1 to 1.4 mm were used in the experiment. 100 mg of sorbents were used in the fixed bed type reactor. Scanning electron microscope and energy dispersive x-ray diffraction analysis were done for virgin and chemically impregnated AC. Three different inlet mercury concentration (135, 300 and 580 μg/m3 ) and four temperatures (80, 100, 120 and 140°C) were investigated using chemically treated activated carbon for shorter time duration. Experiments were also done for long duration of time till the breakthrough. The results suggested that the chemically treated activated carbons were effective in capturing mercury. Hydrochloric acid (HCl) impregnated activated carbon had adsorption capacity of 2.6 milligram of mercmy per gram of sorbent at 90% breaktlu·ough. On the other hand, potassium iodide (KI) impregnated activated carbon exhibited remarkably superior mercmy adsorption capacity with 11 milligram of mercury per gram of sorbent at 90% breakthrough. Although iodine is less reactive than chlorine and KI is a stable salt, it was seen that KI impregnated activated carbon performed much better that HCl impregnated ones. There was ve1y little effect of temperature in the tested range. However inlet concentration had significant effect as the mercury removal capacity in terms of amount of sorbate adsorbed increased with the increase in inlet mercury concentration. Additionally, though chemisorptions is clearly needed for capturing the elemental mercury, the experimental results also showed physisorption behavior in overall, the reason for which however could not be explained. This signifies that the mechanism of removal of elemental mercury from flue gas is very complicated. Speculations are being made that chemical adsorption may be the governing mechanism with chemical reactions between mercury and impregnated chemicals. |
| Year | 2003 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-03-24 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Nguyen Thi Kim Oanh |
| Examination Committee(s) | Jurng, Jongsoo ;Lee, Seung-Hwan ;Visvanathan, C. |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship. |