Since the first batch of 350-MW supercritical utility boilers was put into operation, the exhaust flue gas temperature of the boilers has always been higher than the designed value. The main reason is that the heat ab...Since the first batch of 350-MW supercritical utility boilers was put into operation, the exhaust flue gas temperature of the boilers has always been higher than the designed value. The main reason is that the heat absorbed by the air heater is not sufficient. In Huaneng Dongfang Power Plant, the exhaust flue gas temperature is lowered through modifications to the economizer and the air heater. The experimental results reveal that every year, each boiler could save 3 850 tons of standard coal and reduce 85 tons of SO2 and 9 000 tons of CO2 respectively after retrofit.展开更多
This article reviews the problems of Russia-made 800-MW coal-fired supercritical boilers in Suizhong Power Plant, such as burner bumout, water-wall leakage, slag screenⅠexplosion, crack happened on the desuperheater ...This article reviews the problems of Russia-made 800-MW coal-fired supercritical boilers in Suizhong Power Plant, such as burner bumout, water-wall leakage, slag screenⅠexplosion, crack happened on the desuperheater outlet of reheater and welding defect of economizer; tells the process of renovating these units by modifying the original design and adjusting the operation parameters. After several years' effort, all the problems have been well solved. The experience may be useful for other imported units in China.展开更多
Poly(1,1,2,2- tetrahydroperfluorodecyl acrylate) (poly (TA-N)) was synthesized in laboratory. The resulting morphology of rapid expansion of supercritical solution (RESS) sprays of poly(TA - N) was investigated. At ap...Poly(1,1,2,2- tetrahydroperfluorodecyl acrylate) (poly (TA-N)) was synthesized in laboratory. The resulting morphology of rapid expansion of supercritical solution (RESS) sprays of poly(TA - N) was investigated. At apre - expansion temperature of 45℃), amorphous polymer was formed. At temperature around 60 ℃ to 80 ℃ , fibers were formed. Increase of temperature increasesparticle size slightly. At temperature of 105℃ , most of particles are spheres. The RESS is an attractive process. To apply the polymers desired for coating applications in an organic solvent - free process that is economically viable , and it will have implications for pollution prevention during polymer film展开更多
In this paper, compressible flow of aviation kerosene at supercritical conditions has been studied both numerically and experimentally. The thermophysical properties of supercritical kerosene are calculated using a 10...In this paper, compressible flow of aviation kerosene at supercritical conditions has been studied both numerically and experimentally. The thermophysical properties of supercritical kerosene are calculated using a 10- species surrogate based on the principle of extended corresponding states （ECS）. Isentropic acceleration of supercritical kerosene to subsonic and supersonic speeds has been analyzed numerically. It has been found that the isentropic relationships of supercritical kerosene are significantly dif- ferent from those of ideal gases, A two-stage fuel heating and delivery system is used to heat the kerosene up to a tem- perature of 820 K and pressure of 5.5 MPa with a maximum mass flow rate of 100 g/s. The characteristics of supercritical kerosene flows in a converging-diverging nozzle （Laval nozzle） have been studied experimentally. The results show that stable supersonic flows of kerosene could be established in the temperature range of 730 K-820 K and the measurements in the wall pressure agree with the numerical calculation.展开更多
Extracts are important components of fuels. Fatty-extracts with high heating value （HV） are hypothe- sized by researchers as positively related to the HV of fuels. The Soxhlet extractor is typically used to extract ...Extracts are important components of fuels. Fatty-extracts with high heating value （HV） are hypothe- sized by researchers as positively related to the HV of fuels. The Soxhlet extractor is typically used to extract fatty-extracts but it has shortcomings, including long processing time （8-10 h） and the requirement for large amounts of organic solvent. Supercritical extraction is an alternate and useful technique for extraction of natural products. However, published studies rarely discuss the relationship between extracts and HV. In this study, we assessed the supercritical extracts （SUE） of forest fuels in the Great Xing＇an Mountains. Our results indicated that the optimum conditions for extraction of SuEs were 40-60 mesh, 40-50 MPa, 45℃, 80 min and a CO2 flow rate of 1.5-2.0 dm3/min. The Soxhlet extracts contents and the SuE contents were all related to HV. However, R2 of the coniferous samples （0.8499） and needle samples （0.9722） demonstrated that the correlation between HV and the SuE content was closer. We conclude that supercritical fatty-extracts provide a useful index of the HV of fuels, especially coniferous fuels. SuE data can be used in fire management, for example to estimate the rate of fire spread or fire intensity.展开更多
In this paper,a numerical model was built by ANSYS FLUENT to investigate the heat transfer performances of supercritical water in a circumferential non-uniformly heated vertical tube.The Shear Stress Transport(SST)k-...In this paper,a numerical model was built by ANSYS FLUENT to investigate the heat transfer performances of supercritical water in a circumferential non-uniformly heated vertical tube.The Shear Stress Transport(SST)k-ωmodel was adopted for describing turbulence.The operating parameters are chosen according to a 660 MW ultra-supercritical CFB boiler.The heat transfer performances under different operating parameters,such as boiler load,flow direction and heat flux distribution are analyzed.The temperature and heat flux on inner wall varies along the circumference and show symmetric distributions.The overall heat transfer performances at each cross section are better than the local heat transfer performance of midpoint of heating side.Flow direction has a great influence on heat transfer performance;it changes the radial distribution of axial velocity and then affects the turbulence distribution.Therefore,upward flow condition shows a better heat transfer performance.Smaller heat flux improves both the overall and local heat transfer performances.Reducing the heat flux area is not conducive to the overall heat transfer,but does not affect the local heat transfer at the midpoint of heating side.Finally,a new correlation is fitted based on the simulated results of supercritical water heat transfer with circumferential non-uniform heat flux distributions.展开更多
The use of supercritical fluid carbon dioxide (SFCO2) in extraction of lanolin and its alcohol is superior to the conventional solvent extraction method. Its distinctive advantages include high extractive ratio, nonto...The use of supercritical fluid carbon dioxide (SFCO2) in extraction of lanolin and its alcohol is superior to the conventional solvent extraction method. Its distinctive advantages include high extractive ratio, nontoxic and nonflammable solvents, and minimal by -product pollution. The resulting refined lanolin and its alcohol have light color and little odor, and can be used as raw materials for high grade cosmetic products.展开更多
文摘Since the first batch of 350-MW supercritical utility boilers was put into operation, the exhaust flue gas temperature of the boilers has always been higher than the designed value. The main reason is that the heat absorbed by the air heater is not sufficient. In Huaneng Dongfang Power Plant, the exhaust flue gas temperature is lowered through modifications to the economizer and the air heater. The experimental results reveal that every year, each boiler could save 3 850 tons of standard coal and reduce 85 tons of SO2 and 9 000 tons of CO2 respectively after retrofit.
文摘This article reviews the problems of Russia-made 800-MW coal-fired supercritical boilers in Suizhong Power Plant, such as burner bumout, water-wall leakage, slag screenⅠexplosion, crack happened on the desuperheater outlet of reheater and welding defect of economizer; tells the process of renovating these units by modifying the original design and adjusting the operation parameters. After several years' effort, all the problems have been well solved. The experience may be useful for other imported units in China.
文摘Poly(1,1,2,2- tetrahydroperfluorodecyl acrylate) (poly (TA-N)) was synthesized in laboratory. The resulting morphology of rapid expansion of supercritical solution (RESS) sprays of poly(TA - N) was investigated. At apre - expansion temperature of 45℃), amorphous polymer was formed. At temperature around 60 ℃ to 80 ℃ , fibers were formed. Increase of temperature increasesparticle size slightly. At temperature of 105℃ , most of particles are spheres. The RESS is an attractive process. To apply the polymers desired for coating applications in an organic solvent - free process that is economically viable , and it will have implications for pollution prevention during polymer film
基金supported by the National Natural Science Foundation of China (10672169 and 10902115)
文摘In this paper, compressible flow of aviation kerosene at supercritical conditions has been studied both numerically and experimentally. The thermophysical properties of supercritical kerosene are calculated using a 10- species surrogate based on the principle of extended corresponding states （ECS）. Isentropic acceleration of supercritical kerosene to subsonic and supersonic speeds has been analyzed numerically. It has been found that the isentropic relationships of supercritical kerosene are significantly dif- ferent from those of ideal gases, A two-stage fuel heating and delivery system is used to heat the kerosene up to a tem- perature of 820 K and pressure of 5.5 MPa with a maximum mass flow rate of 100 g/s. The characteristics of supercritical kerosene flows in a converging-diverging nozzle （Laval nozzle） have been studied experimentally. The results show that stable supersonic flows of kerosene could be established in the temperature range of 730 K-820 K and the measurements in the wall pressure agree with the numerical calculation.
基金sponsored by the National Natural Science Foundation of China(Grant number:31170618)the National Key Technologies R&D Program of China(Grant number2011BAD32B05)
文摘Extracts are important components of fuels. Fatty-extracts with high heating value （HV） are hypothe- sized by researchers as positively related to the HV of fuels. The Soxhlet extractor is typically used to extract fatty-extracts but it has shortcomings, including long processing time （8-10 h） and the requirement for large amounts of organic solvent. Supercritical extraction is an alternate and useful technique for extraction of natural products. However, published studies rarely discuss the relationship between extracts and HV. In this study, we assessed the supercritical extracts （SUE） of forest fuels in the Great Xing＇an Mountains. Our results indicated that the optimum conditions for extraction of SuEs were 40-60 mesh, 40-50 MPa, 45℃, 80 min and a CO2 flow rate of 1.5-2.0 dm3/min. The Soxhlet extracts contents and the SuE contents were all related to HV. However, R2 of the coniferous samples （0.8499） and needle samples （0.9722） demonstrated that the correlation between HV and the SuE content was closer. We conclude that supercritical fatty-extracts provide a useful index of the HV of fuels, especially coniferous fuels. SuE data can be used in fire management, for example to estimate the rate of fire spread or fire intensity.
基金financially supported by the National Key Research&Development Program of China(2022YFB4100303)。
文摘In this paper,a numerical model was built by ANSYS FLUENT to investigate the heat transfer performances of supercritical water in a circumferential non-uniformly heated vertical tube.The Shear Stress Transport(SST)k-ωmodel was adopted for describing turbulence.The operating parameters are chosen according to a 660 MW ultra-supercritical CFB boiler.The heat transfer performances under different operating parameters,such as boiler load,flow direction and heat flux distribution are analyzed.The temperature and heat flux on inner wall varies along the circumference and show symmetric distributions.The overall heat transfer performances at each cross section are better than the local heat transfer performance of midpoint of heating side.Flow direction has a great influence on heat transfer performance;it changes the radial distribution of axial velocity and then affects the turbulence distribution.Therefore,upward flow condition shows a better heat transfer performance.Smaller heat flux improves both the overall and local heat transfer performances.Reducing the heat flux area is not conducive to the overall heat transfer,but does not affect the local heat transfer at the midpoint of heating side.Finally,a new correlation is fitted based on the simulated results of supercritical water heat transfer with circumferential non-uniform heat flux distributions.
基金Science Foundation of National Education Commission(99053)
文摘The use of supercritical fluid carbon dioxide (SFCO2) in extraction of lanolin and its alcohol is superior to the conventional solvent extraction method. Its distinctive advantages include high extractive ratio, nontoxic and nonflammable solvents, and minimal by -product pollution. The resulting refined lanolin and its alcohol have light color and little odor, and can be used as raw materials for high grade cosmetic products.
