Environ Sci Pollut Res DOI 10.1007/s11356-014-3689-7
RESEARCH ARTICLE
Destruction of representative submarine food waste using supercritical water oxidation Shiying Chen & Xuan Qu & Rong Zhang & Jicheng Bi
Received: 23 May 2014 / Accepted: 2 October 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract In this study, 13 types of organic materials were oxidized using H2O2 in a continuous flow reactor under the condition of supercritical water. The effect of the operational parameters on the conversion of total organic carbon (TOC) and total nitrogen (TN) was investigated, and the resulting quality of treated water was analyzed. It was found that these materials were easily oxidized with a TOC conversion achieving 99 % at temperature of 460 °C and TN conversion reaching 94 % at temperature of 500 °C. Rice decomposition was rapid, with TOC and TN decomposition rates of 99 % obtained within residence of 100 s at temperature of 460 °C. At temperature of 460 °C, pressure of 24 MPa, residence time of 100 s, and excess oxygen of 100 %, the quality of treated water attained levels commensurate with China’s Standards for Drinking Water Quality. Reaction rate equation parameters were obtained by fitting the experimental data to the differential equation obtained using the Runge–Kutta algorithm. The decrease of the TOC in water samples exhibited reaction orders of 0.95 for the TOC concentration and 0.628 for the oxygen concentration. The activation energy was 83.018 kJ/mol. Keywords Supercritical water oxidation . Food waste . Submarine . Kinetics modeling . Water recycling Responsible editor: Angeles Blanco S. Chen (*) : X. Qu : R. Zhang : J. Bi (*) State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, 030001 Taiyuan, People’s Republic of China e-mail: [email protected] e-mail: [email protected] S. Chen University of Chinese Academy of Sciences, 100049 Beijing, People’s Republic of China
Introduction A closed system has special environmental conditions, which requires internal processing of the waste to the extent possible. A submarine is a typical closed system, in which considerable quantities of food waste are generated. A concentric trash disposal unit (TDU)-centric is employed in a submarine to process food waste (Miles et al. 1996). Usually, management of food waste in a submarine is centered on ejecting of the offending material from the submarine. Generally speaking, there are two methods for treating the food waste in submarine. One centers on compacting the garbage followed by discharging it directly into sea using the medium pressure air. The lighter waste will float to the sea surface and an area of flotsam is formed. In the process, large quantities of air bubbles are emitted, which will compromise the concealment of the submarine. The second method centers on compacting the garbage and weighting the “package” which is expelled from the vessel causing the garbage to sink. This method is time-consuming and is forbidden when the submarine is running silently in the hunter mode. Moreover, sea disposal has been outlawed in many areas by MARPOL 73/78 (Polglaze 2003). As a result, new approaches are necessarily for dealing with the treatment of garbage on submarines. Supercritical water is an excellent medium for rapid oxidative destruction of organic compounds. Above the critical point (Tc =374 °C, Pc =22.1 MPa), water becomes a complete non-polar solvent, in which organics and oxygen react easily (Modell 1989a, b). At typical operating conditions (T=450– 700 °C, P = 23–30 MPa), high destruction efficiencies (≥99.99 %) of organics in short residence times (
RESEARCH ARTICLE
Destruction of representative submarine food waste using supercritical water oxidation Shiying Chen & Xuan Qu & Rong Zhang & Jicheng Bi
Received: 23 May 2014 / Accepted: 2 October 2014 # Springer-Verlag Berlin Heidelberg 2014
Abstract In this study, 13 types of organic materials were oxidized using H2O2 in a continuous flow reactor under the condition of supercritical water. The effect of the operational parameters on the conversion of total organic carbon (TOC) and total nitrogen (TN) was investigated, and the resulting quality of treated water was analyzed. It was found that these materials were easily oxidized with a TOC conversion achieving 99 % at temperature of 460 °C and TN conversion reaching 94 % at temperature of 500 °C. Rice decomposition was rapid, with TOC and TN decomposition rates of 99 % obtained within residence of 100 s at temperature of 460 °C. At temperature of 460 °C, pressure of 24 MPa, residence time of 100 s, and excess oxygen of 100 %, the quality of treated water attained levels commensurate with China’s Standards for Drinking Water Quality. Reaction rate equation parameters were obtained by fitting the experimental data to the differential equation obtained using the Runge–Kutta algorithm. The decrease of the TOC in water samples exhibited reaction orders of 0.95 for the TOC concentration and 0.628 for the oxygen concentration. The activation energy was 83.018 kJ/mol. Keywords Supercritical water oxidation . Food waste . Submarine . Kinetics modeling . Water recycling Responsible editor: Angeles Blanco S. Chen (*) : X. Qu : R. Zhang : J. Bi (*) State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, 030001 Taiyuan, People’s Republic of China e-mail: [email protected] e-mail: [email protected] S. Chen University of Chinese Academy of Sciences, 100049 Beijing, People’s Republic of China
Introduction A closed system has special environmental conditions, which requires internal processing of the waste to the extent possible. A submarine is a typical closed system, in which considerable quantities of food waste are generated. A concentric trash disposal unit (TDU)-centric is employed in a submarine to process food waste (Miles et al. 1996). Usually, management of food waste in a submarine is centered on ejecting of the offending material from the submarine. Generally speaking, there are two methods for treating the food waste in submarine. One centers on compacting the garbage followed by discharging it directly into sea using the medium pressure air. The lighter waste will float to the sea surface and an area of flotsam is formed. In the process, large quantities of air bubbles are emitted, which will compromise the concealment of the submarine. The second method centers on compacting the garbage and weighting the “package” which is expelled from the vessel causing the garbage to sink. This method is time-consuming and is forbidden when the submarine is running silently in the hunter mode. Moreover, sea disposal has been outlawed in many areas by MARPOL 73/78 (Polglaze 2003). As a result, new approaches are necessarily for dealing with the treatment of garbage on submarines. Supercritical water is an excellent medium for rapid oxidative destruction of organic compounds. Above the critical point (Tc =374 °C, Pc =22.1 MPa), water becomes a complete non-polar solvent, in which organics and oxygen react easily (Modell 1989a, b). At typical operating conditions (T=450– 700 °C, P = 23–30 MPa), high destruction efficiencies (≥99.99 %) of organics in short residence times (
