The heat transfer efficiency during the pyrolysis process is a key factor to be considered in the design of pyrolysis reactors. In this study, the average apparent heat transfer characteristics of molten plastic pyrol...The heat transfer efficiency during the pyrolysis process is a key factor to be considered in the design of pyrolysis reactors. In this study, the average apparent heat transfer characteristics of molten plastic pyrolysis in a vertical falling film reactor were explored by experiments and numerical simulation and the apparent heat transfer coefficients were determined. In addition, the temperature distribution and the thickness of the liquid film in the reactor were predicted and the influences of pyrolysis temperatures on the average apparent heat transfer coefficients were discussed.展开更多
Molten plastics are characterised with high viscosity and low thermal conductivity. Applying falling film pyrolysis reactor to deal with waste plastics can not only improve heat transfer efficiency, but also solve the...Molten plastics are characterised with high viscosity and low thermal conductivity. Applying falling film pyrolysis reactor to deal with waste plastics can not only improve heat transfer efficiency, but also solve the flow problem.In this work, the pyrolysis process of molten polypropylene(PP) in a vertical falling film reactor is experimentally studied, and the influence of heating temperature on pyrolysis products is discussed. It has been found that with the temperature increases from 550 ℃ to 625 ℃, the yield of pyrolysis oil decreases from 74.4 wt%(± 2.2 wt%) to53.5 wt%(±1.3 wt%). The major compositions of the pyrolysis oil are C_9, C_(12) and C_(18), and β-scission reactions are predominant. The content of the light fraction C_6-C_(12) of pyrolysis oil is 69.7 wt%. Compared with other pyrolysis reactors, the yield of oil from vertical falling film pyrolysis reactor is slightly higher than that from tubular reactor,equal to that from rotary kiln reactor, and slightly lower than that in medium fluidised-bed reactor.展开更多
Effects of molten state of ultrasonic welded joints of plastics on their strength were investigated. Physical parameters such as temperature, viscosity and thickness of melting layers of plastic material joints were m...Effects of molten state of ultrasonic welded joints of plastics on their strength were investigated. Physical parameters such as temperature, viscosity and thickness of melting layers of plastic material joints were measured and analyzed. Results show that when the welding vibration amplitude and pressure increase, the temperature increases, the viscosity decreases, and the thickness of molten layer decreases. The microstructure of weld fusion zone was observed by using an optical microscope. It was found that there is strong orientation along transverse direction in the microstructure of fusion zone. Testing results show that the mechanics performance of welded joints are obviously anisotropic, and strongly affected by the thickness of molten layer and the extent of orientation.展开更多
基金Supported by the National Natural Science Foundation of China(51,503,154,51,776,141)the Major Projects of China Water Pollution Control and Treatment Science and Technology(2017ZX07202005)
文摘The heat transfer efficiency during the pyrolysis process is a key factor to be considered in the design of pyrolysis reactors. In this study, the average apparent heat transfer characteristics of molten plastic pyrolysis in a vertical falling film reactor were explored by experiments and numerical simulation and the apparent heat transfer coefficients were determined. In addition, the temperature distribution and the thickness of the liquid film in the reactor were predicted and the influences of pyrolysis temperatures on the average apparent heat transfer coefficients were discussed.
基金Supported by the National Natural Science Foundation of China(51503154)Major Projects of China Water Pollution Control and Treatment Science and Technology(2017ZX07202005)the Shanghai Municipal Science and Technology Commission Fund for improving the economy in the Yangtze River Delta region(12195811100)
文摘Molten plastics are characterised with high viscosity and low thermal conductivity. Applying falling film pyrolysis reactor to deal with waste plastics can not only improve heat transfer efficiency, but also solve the flow problem.In this work, the pyrolysis process of molten polypropylene(PP) in a vertical falling film reactor is experimentally studied, and the influence of heating temperature on pyrolysis products is discussed. It has been found that with the temperature increases from 550 ℃ to 625 ℃, the yield of pyrolysis oil decreases from 74.4 wt%(± 2.2 wt%) to53.5 wt%(±1.3 wt%). The major compositions of the pyrolysis oil are C_9, C_(12) and C_(18), and β-scission reactions are predominant. The content of the light fraction C_6-C_(12) of pyrolysis oil is 69.7 wt%. Compared with other pyrolysis reactors, the yield of oil from vertical falling film pyrolysis reactor is slightly higher than that from tubular reactor,equal to that from rotary kiln reactor, and slightly lower than that in medium fluidised-bed reactor.
基金the National Natural Science Foundation of China (No.59675054) andNational Key Laboratory of Advanced Welding Production Techn
文摘Effects of molten state of ultrasonic welded joints of plastics on their strength were investigated. Physical parameters such as temperature, viscosity and thickness of melting layers of plastic material joints were measured and analyzed. Results show that when the welding vibration amplitude and pressure increase, the temperature increases, the viscosity decreases, and the thickness of molten layer decreases. The microstructure of weld fusion zone was observed by using an optical microscope. It was found that there is strong orientation along transverse direction in the microstructure of fusion zone. Testing results show that the mechanics performance of welded joints are obviously anisotropic, and strongly affected by the thickness of molten layer and the extent of orientation.
