The low-temperature wet oxidation behavior of semi-dry desulfurization ash from iron ore sintering flue gas in ammonium citrate solution was investigated for efficiently utilizing the low-quality desulfurization ash.T...The low-temperature wet oxidation behavior of semi-dry desulfurization ash from iron ore sintering flue gas in ammonium citrate solution was investigated for efficiently utilizing the low-quality desulfurization ash.The effects of the ammonium citrate concentration,oxidation temperature,solid/liquid ratio,and oxidation time on the wet oxidation behavior of desulfurization ash were studied.Simultaneously,the oxidation mechanism of desulfurization ash was revealed by means of X-ray diffraction,Zeta electric resistance,and X-ray photoelectron spectroscopy(XPS)analysis.Under the optimal conditions with ammonium citrate,the oxidation ratio of CaSO_(3)was up to the maximum value(98.49%),while that of CaSO_(3)was only 8.92%without ammonium citrate.Zeta electric resistance and XPS results indicate that the dissolution process of CaSO_(3)could be significantly promoted by complexation derived from the ammonium citrate hydrolysis.As a result,the oxidation process of CaSO_(3)was transformed from particle oxidation to SO_(3)^(2−)ion oxidation,realizing the rapid transformation of desulfurization ash from CaSO_(3)to CaSO_(4)at low temperature.It provides a reference for the application of semi-dry desulfurization ash and contributes to sustainable management for semi-dry desulfurization ash.展开更多
Ash deposition is a form of particulate fouling, and appears usually in boiler economizers. The ash deposition increases capital expenditure, energy input and maintenance costs. An analog experiment for monitoring ash...Ash deposition is a form of particulate fouling, and appears usually in boiler economizers. The ash deposition increases capital expenditure, energy input and maintenance costs. An analog experiment for monitoring ash deposition was performed from the analogous objective of a 410 t/h boiler economizer to verify the rationality and reliability of the ash-deposition-monitoring model presented in order to increase the security and economy in economizer running. The analog experiment platform is a tube-shell exchanger that conforms well to the conditions of a self-modeling area. The analog flue gas in the shell side is the heated air mixed with ash, and in the tube side the fluid is water heated by the flue gas. The fluid state in the water side and the flue gas side follows the second self-modeling area. A 4-factor-3-level orthogonal table was used to schedule 9 operation conditions of orthogonal experiment, with the 4 factors being heat power, flue gas velocity, ashes grain diameter and adding ashes quantity while the three levels are different values due to different position classes in every factor. The ash deposition thermal resistances is calculated by the model with the measure parameters of temperature and pressure drop. It shows that the values of the ash deposition thermal resistances gradually increase up to a stable state. And the experimental results are reliable by F testing method at α= 0.001. Therefore, the model can be applied in online monitoring of ash deposition in a boiler economizers in power plants and provides scientific decision on ash deposition prediction and sootblowing.展开更多
The Yanzhou mine district, located in southwestern Shandong Province, is about 1300 km2 with more than 8×109tons of proved coal reserves and there are 10 big power plants in this area. A large amount of coal ashe...The Yanzhou mine district, located in southwestern Shandong Province, is about 1300 km2 with more than 8×109tons of proved coal reserves and there are 10 big power plants in this area. A large amount of coal ashes, which are regarded as waste materials, have been stockpiled in the area and have influenced the environment of the mine district. In this paper, analysis of fly ash samples from three power plants is carried out, the enrichment and concentration of trace elements, Pb, Zn, Cu and As, in coal ashes are analyzed, and petrological and mineralogical characteristics and chemical compositions of coal ashes are studied. The aim of this work is to provide basic scientific data for utilization of ashes and reduction of environmental pollutions.展开更多
基金the National Natural Science Foundation of China(NSFC)(Grant Nos.51704004 and 51674002)the Natural Science Foundation of Anhui Province(Grant No.1808085QE133).
文摘The low-temperature wet oxidation behavior of semi-dry desulfurization ash from iron ore sintering flue gas in ammonium citrate solution was investigated for efficiently utilizing the low-quality desulfurization ash.The effects of the ammonium citrate concentration,oxidation temperature,solid/liquid ratio,and oxidation time on the wet oxidation behavior of desulfurization ash were studied.Simultaneously,the oxidation mechanism of desulfurization ash was revealed by means of X-ray diffraction,Zeta electric resistance,and X-ray photoelectron spectroscopy(XPS)analysis.Under the optimal conditions with ammonium citrate,the oxidation ratio of CaSO_(3)was up to the maximum value(98.49%),while that of CaSO_(3)was only 8.92%without ammonium citrate.Zeta electric resistance and XPS results indicate that the dissolution process of CaSO_(3)could be significantly promoted by complexation derived from the ammonium citrate hydrolysis.As a result,the oxidation process of CaSO_(3)was transformed from particle oxidation to SO_(3)^(2−)ion oxidation,realizing the rapid transformation of desulfurization ash from CaSO_(3)to CaSO_(4)at low temperature.It provides a reference for the application of semi-dry desulfurization ash and contributes to sustainable management for semi-dry desulfurization ash.
文摘Ash deposition is a form of particulate fouling, and appears usually in boiler economizers. The ash deposition increases capital expenditure, energy input and maintenance costs. An analog experiment for monitoring ash deposition was performed from the analogous objective of a 410 t/h boiler economizer to verify the rationality and reliability of the ash-deposition-monitoring model presented in order to increase the security and economy in economizer running. The analog experiment platform is a tube-shell exchanger that conforms well to the conditions of a self-modeling area. The analog flue gas in the shell side is the heated air mixed with ash, and in the tube side the fluid is water heated by the flue gas. The fluid state in the water side and the flue gas side follows the second self-modeling area. A 4-factor-3-level orthogonal table was used to schedule 9 operation conditions of orthogonal experiment, with the 4 factors being heat power, flue gas velocity, ashes grain diameter and adding ashes quantity while the three levels are different values due to different position classes in every factor. The ash deposition thermal resistances is calculated by the model with the measure parameters of temperature and pressure drop. It shows that the values of the ash deposition thermal resistances gradually increase up to a stable state. And the experimental results are reliable by F testing method at α= 0.001. Therefore, the model can be applied in online monitoring of ash deposition in a boiler economizers in power plants and provides scientific decision on ash deposition prediction and sootblowing.
基金This work was supported by the National Natural Science Found of China(40133010,40273035)Natural Science Found of Anhui(04045064)
文摘The Yanzhou mine district, located in southwestern Shandong Province, is about 1300 km2 with more than 8×109tons of proved coal reserves and there are 10 big power plants in this area. A large amount of coal ashes, which are regarded as waste materials, have been stockpiled in the area and have influenced the environment of the mine district. In this paper, analysis of fly ash samples from three power plants is carried out, the enrichment and concentration of trace elements, Pb, Zn, Cu and As, in coal ashes are analyzed, and petrological and mineralogical characteristics and chemical compositions of coal ashes are studied. The aim of this work is to provide basic scientific data for utilization of ashes and reduction of environmental pollutions.
