A lab-scale fluidized bed is setup and pyrolysis experiments are carried out. When temperature ranges from 400 to 700 ℃, the yields of solid residue, bio-oil and syngas range from 36% to 18%, 19% to 30% and 9% to 42%...A lab-scale fluidized bed is setup and pyrolysis experiments are carried out. When temperature ranges from 400 to 700 ℃, the yields of solid residue, bio-oil and syngas range from 36% to 18%, 19% to 30% and 9% to 42%, respectively, and the mass balance of pyrolysis ranges from 80% to 95%. At 400 to 700 ℃, the characteristics of bio-oil are similar and the heat value is about 10 MJ/kg. When the temperature is over 600℃, the yield of syngas increases approximately twice as much as that at 500 ℃. The yields of CO2 and CO increase from 70 to 230 L/kg and 50 to 106 L/kg, respectively, while the yield of syngas only increases about 5% when the temperature increases from 600 to 700 ℃. The results indicate that the pyrolysis mechanism of waste paper is similar from 400 to 700 ℃, while the yield of syngas can be affected by secondary pyrolysis of bio-oil.展开更多
Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas (LNG) cold energy utilization for power gen...Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas (LNG) cold energy utilization for power generation. Cascade utilization of energy is realized in the two thermal cycles, where low-level waste heat,low-temperature exergy and pressure exergy of LNG are utilized efficiently through the system synthesis. The simulations are carried out using the commercial Aspen Plus 10.2, and the results are analyzed. Compared with the conventional Brayton cycle and Rankine cycle, the two novel cycles bring 60.94% and 60% in exergy efficiency, respectively and 53.08% and 52.31% in thermal efficiency, respectively.展开更多
A bottoming cycle system based on CO2 Brayton cycle is proposed to recover the engine exhaust heat. Its performance is compared with the conventional air Brayton cycle under five typical engine conditions. The results...A bottoming cycle system based on CO2 Brayton cycle is proposed to recover the engine exhaust heat. Its performance is compared with the conventional air Brayton cycle under five typical engine conditions. The results show that CO2 Brayton cycle proves to be superior to the air Brayton cycle in terms of the system net output power, thermal efficiency and recovery efficiency. In most cases, the recovery efficiency of CO2 Brayton cycle can be higher than 9% and the system has a better performance at the engine's high operating load, The thermal efficiency can be as large as 24.83% under 100% olaerating load, accordingly, the net outnut nower of 14.86 kW in nhtnined展开更多
The variation of toxic pollutants emission during a feeding cycle was examined by field monitoring from a batch feeding updraft fixed bed gasifier for disposing rural domestic solid waste. Results showed that the cont...The variation of toxic pollutants emission during a feeding cycle was examined by field monitoring from a batch feeding updraft fixed bed gasifier for disposing rural domestic solid waste. Results showed that the content of oxygen in flue gas gradually increased, while SO_2 and HCl in flue gas decreased with time after feeding in a whole feeding cycle. Although large amount of CO was produced during the gasifying, low CO content in flue gas could be obtained after the heat treatment with an electric heating device. The distribution characteristics of dioxin congeners in flue gas indicted the re-synthesis of dioxins after flue gas heating, and the increase of oxygen promoted the synthesis of dioxins. The emission content of dioxins could meet the standard(0.1 ng I-TEQ·m^(-3),GB18458-2014) of China when the oxygen content was controlled below 8.3%. Hence, for a batch feeding gasifier,low oxygen condition should be offered by reducing air intake at the later stage of feeding cycle in order to decrease the re-synthesis of dioxins after the flue gas heating.展开更多
A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasi...A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55 ℃ to 20 ℃ suddenly, 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g/(L·d) and 15 d respectively for MOSW load and retention time, following results were noted: (1) biogas production almost stopped and VFA (volatile fatty acid) accumulated rapidly, accompanied by pH decrease; (2) with low temperature (20 ℃) duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation, (3) the longer the low temperature interval lasted, the more the methanogenic bacteria would decay, hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation: (4) the thermophilic microorganisms were highly resilient to temperature fluctuation.展开更多
The micro-turbine is known as a producer of high-grade energy (work) and also low energy (heat). The following low grade heat energy have been modeled under ISO ambient conditions (international standard organiza...The micro-turbine is known as a producer of high-grade energy (work) and also low energy (heat). The following low grade heat energy have been modeled under ISO ambient conditions (international standard organization), i.e. 15 ℃ and 1 bar, to utilize the waste heat energy of a 200 kW micro-turbine combined with a single effect absorption chiller, an organic ranking cycle using R245fa (ORC-R245 fa) as a working fluid, a multi-effect distillation desalination (MED) and a thermal vapor compression MED Desalination unit (TVC-MED). The thermal comparison was carried out based on an energy and exergy analysis in terms of electric efficiency, exergetic efficiency, carbon footprint, and energy utilization factor (EUF). The software package IPSEpro has been used to model and simulate the proposed power plants. As a result, utilizing the exhaust waste heat energy in single-effect absorption chillier has contributed to stabilize ambient temperature fluctuation, and gain the best exergetic efficiency of 39%, while the EUF has reached 72% and the carbon footprint was reduced by 75% in MED and TVC-MED Desalination respectively. The results also reveal that TVC-MED is more efficient than traditional MED as its gain output ratio (GOR) is improved by 5.5%. In addition, ORC-245fa generates an additional 20% of the micro-turbine electricity generation.展开更多
The temperature is 56.5℃when acetone gas is rectified during the production of powdery phospholipid. If heat exchanger is added, heat energy that is reclaimed can be used by other heaters. On the basis of exchange ho...The temperature is 56.5℃when acetone gas is rectified during the production of powdery phospholipid. If heat exchanger is added, heat energy that is reclaimed can be used by other heaters. On the basis of exchange hot water (51℃) 4m3 every minute, a factory with the productivity of powdery phospholipid being 10 ton a day can save 533.2 ton standard coal which is equivalent to 746.48 ton common coal. If this technique of saving energy and reducing emission could be widely used in correlative industries of all over the country, economic benefits will be prominent.展开更多
Since the constant increase in petroleum price, use of glycerol waste, which is a byproduct from biodiesel production, as a partial replacement for fossil fuels via thermochemical conversion waste to energy processes ...Since the constant increase in petroleum price, use of glycerol waste, which is a byproduct from biodiesel production, as a partial replacement for fossil fuels via thermochemical conversion waste to energy processes is more practical. Gasification reaction has attracted a lot of interest by producing syngas rich in CO and H2. This syngas can be converted to clean liquid fuels, such as methanol and Fischer-Tropsch oil. Nickel and Cobalt catalyst was widely used in steam reforming reaction. ethanol etc. The aim of this work is to prepare and characterize 5.0 and 10.0%wt of Ni and Co catalysts using the impregnation method on various supporters, such as alumina and titanium oxide (TiO2) and to evaluate their catalytic performance. The specific surface area of developed catalysts was measured. X-ray diffraction (XRD) was applied to determine phase and crystallized size of the catalysts. Examination of the morphology. elemental composition and distribution of metal on the catalysts support were carried out using scanning electron microscopy (SEMi and energy dispersion spectroscopy (EDS) and x-ray mapping. The catalytic performance of prepared catalysts was test at 700 and 900℃ temperature of reaction. 1.87% O2. The result showed that the synthesized nickel and cobalt catalysts via impregnation method using Al2O3 and TiO2 as the catalyst support were suitable for glycerol conversion.展开更多
In this paper, the feasibility of application of a solid-absorption system using ammonia and chlorides as working pair to automobile air-conditioning system is investigated. This system has the advantages of minimum e...In this paper, the feasibility of application of a solid-absorption system using ammonia and chlorides as working pair to automobile air-conditioning system is investigated. This system has the advantages of minimum environmental problem and utilizing waste heat from the automobile engine as thermal energy input. Analyses show that the main problem associated with the application of solid-absorption system is the size of the reactors. Techniques to solve this problem are discussed.展开更多
Decomposition of dimethyl sulfide (DMS) in air was investigated experimentally by using a wire-cylinder dielectric barrier discharge (DBD) reactor at room temperature and atmospheric pressure.A new type of high pulse ...Decomposition of dimethyl sulfide (DMS) in air was investigated experimentally by using a wire-cylinder dielectric barrier discharge (DBD) reactor at room temperature and atmospheric pressure.A new type of high pulse voltage source with a thyratron switch and a Blumlein pulse-forming network (BPFN) was adopted in our experiments.The maximum power output of the pulse voltage source and the maximum peak voltage were 1kW and 100kV,respectively.The important parameters affecting odor decomposition,including peak voltage,pulse frequency,gas flow rate,initial concentration,and humidity,which influenced the removal efficiency,were investigated.The results showed that DMS could be treated effectively and almost a 100% removal efficiency was achieved at the conditions with an initial concentration of 832mg/m3 and a gas flow rate of 1000ml/min.Humidity boosts the removal efficiency and improves the energy yield (EY) greatly.The EY of 832mg/m3 DMS was 2.87mg/kJ when the relative humidity was above 30%.In the case of DMS removal,the ozone and nitrogen oxides were observed in the exhaust gas.The carbon and sulfur elements of DMS were mainly converted to carbon dioxide,carbon monoxide and sulfur dioxide.Moreover,sulfur was discovered in the reactor.According to the results,the optimization design for the reactor and the matching of high pulse voltage source can be reckoned.展开更多
An experimental study has been performed systematically on flue gas desulphurization by using circulating fluidized bed. The relationship, between desulphurization efficiency and the parameters of thermodynamics and c...An experimental study has been performed systematically on flue gas desulphurization by using circulating fluidized bed. The relationship, between desulphurization efficiency and the parameters of thermodynamics and chemistry, was investigated basically. It is shown that the bed temperature and the vapor partial pressure in the bed are the important parameters that influence the desulphurization efficiency. The closer the bed temperature to the dew point and the higher the vapor partial pressure, the higher is the desulphurization efficiency. With increasing of Ca/S. the desulphurization efficiency ascends. Comparing with different operating methods, the optimum method has been found.展开更多
A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre...A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre-heated by waste hot water,then heated by the heat pump.Waste heat is recovered by first preheating the cold water and as water source of the heat pump.According to the correlated formulas of the coefficient of performance of air-source heat pump and water-source heat pump,and the gain coefficient of heat recovery-preheater,the formulas for the coefficient of performance of heat pump in six operating modes are obtained by using the dimensionless correspondence analysis method.The system characteristics of heat absorption and release associated with the heat recovery-preheater are analyzed at different working conditions.The developed approaches can provide reference for the optimization of the operating modes and parameters.The results of analysis and experiments show that the coefficient of performance of the device can reach 4-5.5 in winter,twice as much as air source heat pump water heater.The utilization of waste heat in the proposed system is higher than that in the system which only uses waste water to preheating or as heat source.Thus,the effect of energy saving of the new system is obvious.On the other hand,the dimensionless correspondence analysis method is introduced to performance analysis of the heat pump,which also has theoretical significance and practical value.展开更多
基金The National High Technology Research and Devel-opment Program of China (863Program)(No2006AA020101)the National Basic Research Program of China (973Program) ( No2005CB221202)the Open Foundation of State Key Laboratory of CleanEnergy Utilization of Zhejiang University (NoZJUCEU2006004)
文摘A lab-scale fluidized bed is setup and pyrolysis experiments are carried out. When temperature ranges from 400 to 700 ℃, the yields of solid residue, bio-oil and syngas range from 36% to 18%, 19% to 30% and 9% to 42%, respectively, and the mass balance of pyrolysis ranges from 80% to 95%. At 400 to 700 ℃, the characteristics of bio-oil are similar and the heat value is about 10 MJ/kg. When the temperature is over 600℃, the yield of syngas increases approximately twice as much as that at 500 ℃. The yields of CO2 and CO increase from 70 to 230 L/kg and 50 to 106 L/kg, respectively, while the yield of syngas only increases about 5% when the temperature increases from 600 to 700 ℃. The results indicate that the pyrolysis mechanism of waste paper is similar from 400 to 700 ℃, while the yield of syngas can be affected by secondary pyrolysis of bio-oil.
基金the Science and Technology Foundation of Shaanxi Province (No.2002K08-G9).
文摘Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas (LNG) cold energy utilization for power generation. Cascade utilization of energy is realized in the two thermal cycles, where low-level waste heat,low-temperature exergy and pressure exergy of LNG are utilized efficiently through the system synthesis. The simulations are carried out using the commercial Aspen Plus 10.2, and the results are analyzed. Compared with the conventional Brayton cycle and Rankine cycle, the two novel cycles bring 60.94% and 60% in exergy efficiency, respectively and 53.08% and 52.31% in thermal efficiency, respectively.
基金Supported by the National Basic Research Program of China("973"Program,No.2011CB707201)the National Natural Science Foundation of China(No.51206117)
文摘A bottoming cycle system based on CO2 Brayton cycle is proposed to recover the engine exhaust heat. Its performance is compared with the conventional air Brayton cycle under five typical engine conditions. The results show that CO2 Brayton cycle proves to be superior to the air Brayton cycle in terms of the system net output power, thermal efficiency and recovery efficiency. In most cases, the recovery efficiency of CO2 Brayton cycle can be higher than 9% and the system has a better performance at the engine's high operating load, The thermal efficiency can be as large as 24.83% under 100% olaerating load, accordingly, the net outnut nower of 14.86 kW in nhtnined
基金Supported by the Science and Technology Planning Project of Guangdong Province,China(2013B090600134)the National Natural Science Foundation of China(51608223)the Fund for Basic Scientific Research Business of Central Institutes of Environmental Protection(PM-zx 703-201602-050)
文摘The variation of toxic pollutants emission during a feeding cycle was examined by field monitoring from a batch feeding updraft fixed bed gasifier for disposing rural domestic solid waste. Results showed that the content of oxygen in flue gas gradually increased, while SO_2 and HCl in flue gas decreased with time after feeding in a whole feeding cycle. Although large amount of CO was produced during the gasifying, low CO content in flue gas could be obtained after the heat treatment with an electric heating device. The distribution characteristics of dioxin congeners in flue gas indicted the re-synthesis of dioxins after flue gas heating, and the increase of oxygen promoted the synthesis of dioxins. The emission content of dioxins could meet the standard(0.1 ng I-TEQ·m^(-3),GB18458-2014) of China when the oxygen content was controlled below 8.3%. Hence, for a batch feeding gasifier,low oxygen condition should be offered by reducing air intake at the later stage of feeding cycle in order to decrease the re-synthesis of dioxins after the flue gas heating.
基金Project (No. 2002-548) supported by the National Development andReform Commission of China
文摘A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55 ℃ to 20 ℃ suddenly, 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g/(L·d) and 15 d respectively for MOSW load and retention time, following results were noted: (1) biogas production almost stopped and VFA (volatile fatty acid) accumulated rapidly, accompanied by pH decrease; (2) with low temperature (20 ℃) duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation, (3) the longer the low temperature interval lasted, the more the methanogenic bacteria would decay, hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation: (4) the thermophilic microorganisms were highly resilient to temperature fluctuation.
文摘The micro-turbine is known as a producer of high-grade energy (work) and also low energy (heat). The following low grade heat energy have been modeled under ISO ambient conditions (international standard organization), i.e. 15 ℃ and 1 bar, to utilize the waste heat energy of a 200 kW micro-turbine combined with a single effect absorption chiller, an organic ranking cycle using R245fa (ORC-R245 fa) as a working fluid, a multi-effect distillation desalination (MED) and a thermal vapor compression MED Desalination unit (TVC-MED). The thermal comparison was carried out based on an energy and exergy analysis in terms of electric efficiency, exergetic efficiency, carbon footprint, and energy utilization factor (EUF). The software package IPSEpro has been used to model and simulate the proposed power plants. As a result, utilizing the exhaust waste heat energy in single-effect absorption chillier has contributed to stabilize ambient temperature fluctuation, and gain the best exergetic efficiency of 39%, while the EUF has reached 72% and the carbon footprint was reduced by 75% in MED and TVC-MED Desalination respectively. The results also reveal that TVC-MED is more efficient than traditional MED as its gain output ratio (GOR) is improved by 5.5%. In addition, ORC-245fa generates an additional 20% of the micro-turbine electricity generation.
文摘The temperature is 56.5℃when acetone gas is rectified during the production of powdery phospholipid. If heat exchanger is added, heat energy that is reclaimed can be used by other heaters. On the basis of exchange hot water (51℃) 4m3 every minute, a factory with the productivity of powdery phospholipid being 10 ton a day can save 533.2 ton standard coal which is equivalent to 746.48 ton common coal. If this technique of saving energy and reducing emission could be widely used in correlative industries of all over the country, economic benefits will be prominent.
文摘Since the constant increase in petroleum price, use of glycerol waste, which is a byproduct from biodiesel production, as a partial replacement for fossil fuels via thermochemical conversion waste to energy processes is more practical. Gasification reaction has attracted a lot of interest by producing syngas rich in CO and H2. This syngas can be converted to clean liquid fuels, such as methanol and Fischer-Tropsch oil. Nickel and Cobalt catalyst was widely used in steam reforming reaction. ethanol etc. The aim of this work is to prepare and characterize 5.0 and 10.0%wt of Ni and Co catalysts using the impregnation method on various supporters, such as alumina and titanium oxide (TiO2) and to evaluate their catalytic performance. The specific surface area of developed catalysts was measured. X-ray diffraction (XRD) was applied to determine phase and crystallized size of the catalysts. Examination of the morphology. elemental composition and distribution of metal on the catalysts support were carried out using scanning electron microscopy (SEMi and energy dispersion spectroscopy (EDS) and x-ray mapping. The catalytic performance of prepared catalysts was test at 700 and 900℃ temperature of reaction. 1.87% O2. The result showed that the synthesized nickel and cobalt catalysts via impregnation method using Al2O3 and TiO2 as the catalyst support were suitable for glycerol conversion.
文摘In this paper, the feasibility of application of a solid-absorption system using ammonia and chlorides as working pair to automobile air-conditioning system is investigated. This system has the advantages of minimum environmental problem and utilizing waste heat from the automobile engine as thermal energy input. Analyses show that the main problem associated with the application of solid-absorption system is the size of the reactors. Techniques to solve this problem are discussed.
基金Project(No.20576121)supported by the National Natural Science Foundation of China
文摘Decomposition of dimethyl sulfide (DMS) in air was investigated experimentally by using a wire-cylinder dielectric barrier discharge (DBD) reactor at room temperature and atmospheric pressure.A new type of high pulse voltage source with a thyratron switch and a Blumlein pulse-forming network (BPFN) was adopted in our experiments.The maximum power output of the pulse voltage source and the maximum peak voltage were 1kW and 100kV,respectively.The important parameters affecting odor decomposition,including peak voltage,pulse frequency,gas flow rate,initial concentration,and humidity,which influenced the removal efficiency,were investigated.The results showed that DMS could be treated effectively and almost a 100% removal efficiency was achieved at the conditions with an initial concentration of 832mg/m3 and a gas flow rate of 1000ml/min.Humidity boosts the removal efficiency and improves the energy yield (EY) greatly.The EY of 832mg/m3 DMS was 2.87mg/kJ when the relative humidity was above 30%.In the case of DMS removal,the ozone and nitrogen oxides were observed in the exhaust gas.The carbon and sulfur elements of DMS were mainly converted to carbon dioxide,carbon monoxide and sulfur dioxide.Moreover,sulfur was discovered in the reactor.According to the results,the optimization design for the reactor and the matching of high pulse voltage source can be reckoned.
文摘An experimental study has been performed systematically on flue gas desulphurization by using circulating fluidized bed. The relationship, between desulphurization efficiency and the parameters of thermodynamics and chemistry, was investigated basically. It is shown that the bed temperature and the vapor partial pressure in the bed are the important parameters that influence the desulphurization efficiency. The closer the bed temperature to the dew point and the higher the vapor partial pressure, the higher is the desulphurization efficiency. With increasing of Ca/S. the desulphurization efficiency ascends. Comparing with different operating methods, the optimum method has been found.
基金supported by the National Natural Science Foundation of China (Grant No. 51076147)
文摘A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre-heated by waste hot water,then heated by the heat pump.Waste heat is recovered by first preheating the cold water and as water source of the heat pump.According to the correlated formulas of the coefficient of performance of air-source heat pump and water-source heat pump,and the gain coefficient of heat recovery-preheater,the formulas for the coefficient of performance of heat pump in six operating modes are obtained by using the dimensionless correspondence analysis method.The system characteristics of heat absorption and release associated with the heat recovery-preheater are analyzed at different working conditions.The developed approaches can provide reference for the optimization of the operating modes and parameters.The results of analysis and experiments show that the coefficient of performance of the device can reach 4-5.5 in winter,twice as much as air source heat pump water heater.The utilization of waste heat in the proposed system is higher than that in the system which only uses waste water to preheating or as heat source.Thus,the effect of energy saving of the new system is obvious.On the other hand,the dimensionless correspondence analysis method is introduced to performance analysis of the heat pump,which also has theoretical significance and practical value.