Ma W.,Tianjin University |
Rotter V.S.,TU Berlin |
Shao D.,Tianjin TEDA environmental protection Co. |
Chen G.,Tianjin University
18th Annual North American Waste-to-Energy Conference, NAWTEC18 | Year: 2010
Waste-to-energy (WTE) plants are utilized for the production of heat and electricity from municipal solid waste (MSW) and refuse derived fuel (RDF). Due to high chlorine content (0.5wt.%~1.0wt.%) in MSW & RDF, high temperature corrosion is often observed on the superheater surfaces and correspondingly leads to a very low efficiency of 15%~25% in practical WTE plants. To obtain information on the corrosion rate and high temperature corrosion mechanism, a full scale nine-month-long term corrosion test was therefore conducted in a heat and power generating WTE plant in Tianjin, China. The grate boiler with a capacity of 400 tons/d, runs at a burning temperature between 850~900°C, flue gas temperature between 550~650°C, steam temperature of 400°C, and steam pressure of 4MPa. The corrosion probes made of same metal alloy with heat exchanger were exposed on the surface of economizer, protector and superheater, respectively. The metal loss by corrosion was determined by measuring the distance from the inside of the ring to the interface between metal and oxide with a measuring microscope. The deposit characteristics as well as elemental compositions were determined using a scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The objective of this work is to evaluate: 1) plant specific corrosion rate on different superheater materials and 2) relationship among chlorine content in the feedstock, chlorine gas emission before air pollutant clean system, and deposits composition. The results showed deposits characteristics depend on the probe location, metal materials, temperature and windward/leeward. Barely chlorine exists in the deposits, except for the outer surface of the deposits at 3rd SH. The highest corrosion loss for 20G at 3rd SH was calculated to be 2mm/year, based on the assumption of linear extrapolation of corrosion rate. © 2010 by ASME.
Li W.,Nankai University |
Hua T.,Nankai University |
Hua T.,Tianjin TEDA environmental protection Co. |
Zhou Q.,Nankai University |
And 3 more authors.
Desalination | Year: 2010
The experiments were conducted to investigate whether the combined process of coagulation/ flocculation and powder activated carbon (PAC) adsorption was an efficient treatment method for stabilized landfill leachate. In coagulation/flocculation experiments, coagulants including aluminum sulphate (Al2(SO4)3), ferric chloride (FeCl3), polyaluminium chloride (PACl), and polyferric sulphate (PFS) were employed to study the optimum conditions for the removal of COD, SS and turbidity by jartests. The optimum working pH for the tested coagulants was 5.5-6.0, which confirmed charge neutralization as the main mechanism of coagulation/flocculation process. The optimum dosages were 0.6 gAl3+/L for Al2(SO4)3 and PACl, 0.6 g Fe3+/L for FeCl3 and 0.3 g Fe3+/L for PFS, respectively. Among the tested coagulants, PFS showed the highest COD removal efficiency (70%), SS removal efficiency (93%), turbidity removal efficiency (97%), toxicity reduction (74%) and the least sludge volume (32 mL). The adsorption experiments suggested that the dosage of PAC=10 g/L and the contact time=90 min were the appropriate working conditions. Under the optimum condition, the removal efficiencies of COD, Pb, Fe and toxicity of the stabilized landfill leachate were up to 86%, 97.6%, 99.7% and 78%, respectively, by the combined coagulation/flocculation and adsorption process. © 2010 Elsevier B.V.
Wang J.W.,CAS Research Center for Eco Environmental Sciences |
Wang J.W.,Tianjin TEDA environmental protection Co. |
Wang J.W.,Tianjin Esun Environmental Technology Co. |
Zhang H.J.,CAS Dalian Institute of Chemical Physics |
And 6 more authors.
Advanced Materials Research | Year: 2013
In this paper, we present the data regarding the thermal decomposition of PCDD/Fs during the manufacturing process of ceramisite from MSWI fly ash, and the efficiency of "bag filter with activated carbon injection" technology to reduce the gas emission of PCDD/Fs. The distribution of seventeen 2,3,7,8-chlorinated dioxins and furans in MSWI fly ash, ceramisite product, bag filter ash and emission gases were analyzed, and the international toxic equivalents (I-TEQ as 2,3,7,8-tetraCDD) values were calculated by using international-toxicity equivalency factor (I-TEF). The total I-TEQ value of PCDD/Fs in MSWI fly ash reached up to 904.944 ng/kg. After high temperature calcining, only 1.250 ng I-TEQ/kg of PCDD/Fs is left in the ceramisite product. The concentrations of PCDD/Fs in two kinds of bag filter ashes, with activated carbon injection (AC) and without activated carbon injection (NAC), were 324.723 ng I-TEQ/kg and 217.066 ng I-TEQ/kg, respectively. The distribution patterns of seventeen 2,3,7,8-chlorinated dioxins and furans in MSWI fly ash, ceramisite product and bag filter ashes are alike, which suggested that the secondary formation of PCDD/Fs did not significantly occur during the thermal process of manufacturing ceramisite from MSWI fly ash. When no activated carbon was injected, the gas emission of PCDD/Fs was 0.373 ng I-TEQ/Nm3, but 100 mg/Nm3 of activated carbon injection, the gas emission of PCDD/Fs was declined to 0.081 ng I-TEQ/Nm3, which is lower than the gas emission limit established by the European Union Directive of 0.1 ng I-TEQ/Nm3. Therefor, we can recommend that the manufacturing ceramisite from MSWI fly ash using the developed rotary kiln system is an effective measure to safely dispose the MSWI fly ash on the aspect of dioxin emission control. © (2013) Trans Tech Publications, Switzerland.
Han M.,Tianjin TEDA environmental protection Co. |
Han M.,Dalian Teda Environmental Protection Co. |
Dong C.-J.,Tianjin TEDA environmental protection Co. |
Gao L.,Tianjin TEDA environmental protection Co. |
Liu F.-H.,BeiJing Yanshan Petrochemical Company
Advanced Materials Research | Year: 2012
Employing air at normal temperature and pressure as fluid media, the effect of twisted slice on fluid dynamics performances of fluid in cracking furnace tube was studied. The experimental results showed that boundary layer in cracking furnace tube fixed with twisted slice became thin, which leaded to the increase of heat transfer coefficient. So heat transfer was enhanced. Axial velocity distribution in central area of the tube fixed with twisted slice was smoother than that of circular tube, while velocity grad in near wall area was greater. Pressure drop increased in the tube fixed with twisted slice, whereas pressure distribution was even along axial length of the tube, in agreement with the pressure distribution in circular tube. © (2012) Trans Tech Publications.
Hao Y.-J.,Tianjin University |
Hao Y.-J.,Tianjin TEDA environmental protection Co. |
Ji M.,Tianjin University |
Chen Y.-X.,Zhejiang University |
And 3 more authors.
Waste Management and Research | Year: 2010
In-situ ammonium removal from municipal solid waste (MSW) landfill is an attractive method due to its economic advantages. In this study, two simulated MSW bioreactors with different degrees of initial bio-stabilization were utilized to investigate the effects of intermittent aeration mode and the addition of activated sludge on the removal of ammonium. The results showed that up to 90% of ammonium could be removed and the amount of NOx-N produced was less than 1% of NH4 +-N removed in both reactors. The pH values increased rapidly and finally arrived at a high level of 8.5-8.8. The efficiency of ammonium removal was improved by increasing the continuous aeration time, but it was not affected by the addition of activated sludge. A portion of liquid escaped from the reactors in the form of vapour, and as high as 195-258 mg L-1 of NH4 +-N was detected in the vapour collector. According to calculation, nitrification was inhibited by the high level of free ammonia in the bioreactors. As a result, air stripping was enhanced and became the primary pathway of ammonium removal. Therefore, controlling free ammonia concentration was essential in ammonium removal from the aerated MSW bioreactor. © The Author(s), 2010.