The equation for radiation heat transfer in a multiple combustion boiler furnace with nuidized bed and pulverized coal firing is derived from direct calculation of radiation heat transfer.
The applications of fly ash and slag from circulating fluidized bed boiler were studied as mineral admixture and aggregate for steel reinforced concrete beam.The results show that the concrete beam with fly ash and sl...The applications of fly ash and slag from circulating fluidized bed boiler were studied as mineral admixture and aggregate for steel reinforced concrete beam.The results show that the concrete beam with fly ash and slag from circulating fluidized bed boilers has a similar ultimate cracking load coefficient as the ordinary cement concrete and a higher bending moment limit.Under the same load,it has a smaller deformation than the ordinary concrete.展开更多
A liquid-solid circulating fluidized bed boiler is designed and built for visualization research by applying the fluidized bed heat transfer and fouling prevention technology to the water side of the boiler. Four type...A liquid-solid circulating fluidized bed boiler is designed and built for visualization research by applying the fluidized bed heat transfer and fouling prevention technology to the water side of the boiler. Four types of engineering plastic particles with different physical properties are selected as the solid working media. The effect of particle types on the fluidization and distribution of particles in the boiler is investigated under different feedwater flow rates and amount of added particles by using the charge couple device image measurement and acquisition system. The results show that all kinds of particles can't be normally fluidized and accumulate in the drum at low amount of added particles and feedwater flow rate. The particles with great density and low sphericity are more likely to accumulate. The average solid holdup in the riser tubes increases with the increase in feedwater flow rate and the amount of added particles. The non-uniform degree of particle distribution in the riser tubes generally decreases with the increase in feedwater flow rate and the amount of added particles. The particles with small density and settling velocity have high average solid holdup in the riser tubes under close sphericity. In generally,the smaller the density and settling velocity, the more uniform the particle distribution in the riser tubes.Three-dimensional diagrams of the non-uniform degree of particle distribution in the riser tubes of the boiler are established.展开更多
An improved mathematical model for a circulating fluidized bed (CFB) boiler based on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler. The influences of the excess...An improved mathematical model for a circulating fluidized bed (CFB) boiler based on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler. The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.展开更多
Recently, a large amount of circulating fluidized bed boiler ash (CFBA) and desulfurization gypsum (DSG) has been produced, and it is essential to develop technology to utilize them. These materials have CaO and SO<...Recently, a large amount of circulating fluidized bed boiler ash (CFBA) and desulfurization gypsum (DSG) has been produced, and it is essential to develop technology to utilize them. These materials have CaO and SO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">, which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> considered to be a stimulant for blast furnace slag (BFS). This study presents an experimental investigation of the compressive strength and heavy metal ions immobilization properties of cement-free materials comprising CFBA, BFS, and DSG. The feasibility of manufacturing foamed concrete using these materials was examined, and field test of foamed concrete was conducted. Experimentally, the flow, compressive strength, and heavy metal ions concentration were evaluated via inductively coupled plasma atomic emission spectroscopy (ICP</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">AES) of the paste and foamed concrete. The experimental investigation revealed the self-healing hardening ability of fluidized bed boiler ash. In addition, the compressive strength was increased with the increasing replacement rates of BFS and DSG in the CFBA paste, and the compressive strength of 14.6</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> - </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">17.2 MPa was recorded over 28 days of curing. From the result obtained, the feasibility of manufacturing foamed concrete with a foam volume </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">120 L, incorporating the aforementioned materials, is confirmed. It was also found that after 28 days of age, a 7.9-MPa compressive strength of the foamed concrete was attained, and heavy metal ions elution in this foamed concrete was also significantly reduced. Therefore, CFBA, BFS, and DSG could be used as a binder for the foamed concrete.展开更多
Along with the rapid development of the industrialization process in our country in recent years, overall for industrialized production and construction in China put forward the new requirements. It is important to en...Along with the rapid development of the industrialization process in our country in recent years, overall for industrialized production and construction in China put forward the new requirements. It is important to ensure that industrial production in the process of construction safety and quality, especially in recent years, our country the development of the circulating fluidized bed boiler equipment affected by the current state and factory industrial market. With the rapid development of science and technology in recent years, many new technologies and new equipment will be applied to the overall design of circulating fluidized bed boiler. This paper will be circulating fluidized bed boiler slag removal system in my company's actual application of a detailed introduction, clear circulating fluidized bed boiler slag removal system today's development.展开更多
Under the national policy of vigorously promoting biomass fuel as clean fuel, biomass fuel as boiler fuel is the need of the development of the times. Combined with the current biomass fuel policy, this paper introduc...Under the national policy of vigorously promoting biomass fuel as clean fuel, biomass fuel as boiler fuel is the need of the development of the times. Combined with the current biomass fuel policy, this paper introduces the structural design characteristics of a circulating fluidized bed boiler burning biomass fuel, and explains in detail the design of each part of the boiler.展开更多
With the continuous acceleration of social and economic development and the increasing expansion of boiler production scale, circulating fluidized bed boiler has become a necessary facility for industrial production. ...With the continuous acceleration of social and economic development and the increasing expansion of boiler production scale, circulating fluidized bed boiler has become a necessary facility for industrial production. Affected by various factors, the water wall tube explosion of circulating fluidized bed boiler is very easy to occur during operation, which seriously affects the economic and safety benefits during the production, operation and construction of the enterprise. In view of this, taking 130t / h circulating fluidized bed boiler as an example, this paper puts forward the macro damage of the outlet nozzle of the circulating fluidized bed boiler, analyzes the macro and micro morphology of the fracture of the cracked pipe, and carries out micro hardness test and tensile test on the mechanical properties of the outlet nozzle. Finally, the reasons leading to the cracks in the export results are obtained, and the corresponding preventive countermeasures are formulated based on these reasons, in order to provide theoretical help for relevant staff.展开更多
When large-scale circulating fluidized bed(CFB)boilers are working under a 1ow load condition.severe bed pressure swing often occurs and poses a serious threat to boiler stability and safety.Up to now,there are not en...When large-scale circulating fluidized bed(CFB)boilers are working under a 1ow load condition.severe bed pressure swing often occurs and poses a serious threat to boiler stability and safety.Up to now,there are not enough theoretical studies on the bed pressure swing phenomenon.展开更多
Regulation of gas–solid flow is crucial for optimizing the operation efficiency of dual-circulating fluidized beds that are considered to be the most appropriate type of chemical-looping reactors. Herein, a computati...Regulation of gas–solid flow is crucial for optimizing the operation efficiency of dual-circulating fluidized beds that are considered to be the most appropriate type of chemical-looping reactors. Herein, a computational particle fluid dynamics method was employed to simulate the gas–solid flow in a 3-MWth dual-circulating fluidized bed used for chemical-looping combustion and gasification. The influence of structural difference between units on particle residence time was determined. The multi-parameter control mechanism of pressure, particle circulation, and particle residence time in a whole-loop system was investigated. Results revealed that under stable particle circulation, the particle residence time in the fuel reactor is much longer than that in the air reactor. The axial forces on the particles are reduced upon increasing particle density and size, leading to particle accumulation in the dense-phase zone. When the particle properties are stable, increasing the fluidizing gas flow rates by the same proportion leads to identical pressure drops on the involved two loop seals, which cause symmetrical alterations in the particle circulation rate between the air and fuel reactors. The dual-circulating fluidized bed exhibits certain multi-condition adaptability, which is limited by the stock bin volume. Overall, this study is beneficial for effective and economical optimization of the operation of chemical-looping dual-circulating fluidized beds.展开更多
The supercritical circulating fluidized bed(CFB)boiler,which combines the advantages of CFB combustion with low cost emission control and supercritical steam cycle with high efficiency of coal energy,is believed to be...The supercritical circulating fluidized bed(CFB)boiler,which combines the advantages of CFB combustion with low cost emission control and supercritical steam cycle with high efficiency of coal energy,is believed to be the future of CFB combustion technology.It is also of greatest importance for low rank coal utilization in China.Different from the supercritical pulverized coal boiler that has been developed more than 50 years,the supercritical CFB boiler is still a new one which requires further investigation.Without any precedentor engineering reference,Chinese researchers have con ducted fundamental research,development,design of the supercritical CFB boilers independently.The design theory and key technology for supercritical CFB boiler were proposed.Key components and novel structures were invented.The first 600 MWe supercritical CFB boiler and its auxiliaries were successfully developed and demonstrated in Baima Power Plant,Shenhua Group as well as the simulator,control technology,installation technology,commissioning technology,system integration and operation technology.Compared with the 460 MWe supercritical CFB in Poland,developed in the same period and the only other supercritical one of commercial running in the word beside Baima,the 600 MWe one in Baima has a better performance.Besides,supercritical CFB boilers of 350 MWe have been developed and widely commercialized in China.In this paper,the updated progress of 660 MWe ultra-supercritical CFB boilers under development is introduced.展开更多
The co-combustion of low-rank coals through fluidized bed boiler(CFB)is an effective approach to enhance the level of resource utilization.To date,there has been a lack of investigation concerning the co-combustion ki...The co-combustion of low-rank coals through fluidized bed boiler(CFB)is an effective approach to enhance the level of resource utilization.To date,there has been a lack of investigation concerning the co-combustion kinetics and self-desulfurization characteristics of coal slime,coal gangue,and raw coal.In this study,we adopted multiple model-free and model-fitting methods to comparatively analyze co-combustion kinetics of blended coals on the basis of thermogravimetric data.Then,the sulfur balance and self-desulfurization of blended coals in the co-combustion were intensively investigated using a tube furnace set-up.The results reveal that in the presence of coal gangue in blended coals,the average activation energy(E_(a))falls within the range of 65.7 kJ/mol to 100.4 kJ/mol,as determined by four model-free methods.Conversely,in the absence of coal gangue,only the Flynn-Wall-Ozawa(FWO)and Friedman(FM)methods are deemed appropriate for calculating the average E_(a),yielding a value of 77.3 kJ/mol.The first order reaction model is confirmed to be reliable for analyzing the co-combustion kinetics of low-rank blended coals.Irrespective of the specific composition of the blended coal,a significant linear correlation exists between the Ea and the natural logarithm of the pre-exponential factor(lnA)within an extensive range of parameters.Moreover,the addition of coal gangue to the blended coal substantially enhances the self-desulfurization level,resulting in an increase from 25.7%to60.7%at 1073 K.The self-desulfurization efficiency exhibits a good linear relationship with both the mass ratio of coal gangue to coal slime and the molar ratio of calcium to sulfur.In a practical implementation,the optimal addition ratio of coal gangue is a trade-off between the self-desulfurization efficiency and the ignition capacity.展开更多
This paper presents a set of general dynamic mathematical models for the combustion system of acirculating fluidized bi-bed boiler. The models fully consider the flow, combustion and heat transfercharacteristics, and ...This paper presents a set of general dynamic mathematical models for the combustion system of acirculating fluidized bi-bed boiler. The models fully consider the flow, combustion and heat transfercharacteristics, and describe the physical and chemical processes inside the bi-bed, including the gassolid flow, multiple particles combustion, gas chemical reactions, heat transfer and pressure balances,etc.展开更多
A new Kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the princ...A new Kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the principle of thermal equilibrium. A series of cold tests and hot tests were carried to optimize the structure and collocation of water-cooling tubes and showed that the method had the advantage of simple, accurate, reliable and good applicability for on-line "usage in a circulating fluidized bed boiler.展开更多
文摘The equation for radiation heat transfer in a multiple combustion boiler furnace with nuidized bed and pulverized coal firing is derived from direct calculation of radiation heat transfer.
基金Funded by the Foundation of Scientific and Technological Project of Heilongjiang Province,China (GB01A3022)
文摘The applications of fly ash and slag from circulating fluidized bed boiler were studied as mineral admixture and aggregate for steel reinforced concrete beam.The results show that the concrete beam with fly ash and slag from circulating fluidized bed boilers has a similar ultimate cracking load coefficient as the ordinary cement concrete and a higher bending moment limit.Under the same load,it has a smaller deformation than the ordinary concrete.
基金supported by the open foundation of State Key Laboratory of Chemical Engineering (SKL–ChE–18B03)the Municipal Science and Technology Commission of Tianjin, China (2009ZCKFGX01900)。
文摘A liquid-solid circulating fluidized bed boiler is designed and built for visualization research by applying the fluidized bed heat transfer and fouling prevention technology to the water side of the boiler. Four types of engineering plastic particles with different physical properties are selected as the solid working media. The effect of particle types on the fluidization and distribution of particles in the boiler is investigated under different feedwater flow rates and amount of added particles by using the charge couple device image measurement and acquisition system. The results show that all kinds of particles can't be normally fluidized and accumulate in the drum at low amount of added particles and feedwater flow rate. The particles with great density and low sphericity are more likely to accumulate. The average solid holdup in the riser tubes increases with the increase in feedwater flow rate and the amount of added particles. The non-uniform degree of particle distribution in the riser tubes generally decreases with the increase in feedwater flow rate and the amount of added particles. The particles with small density and settling velocity have high average solid holdup in the riser tubes under close sphericity. In generally,the smaller the density and settling velocity, the more uniform the particle distribution in the riser tubes.Three-dimensional diagrams of the non-uniform degree of particle distribution in the riser tubes of the boiler are established.
文摘An improved mathematical model for a circulating fluidized bed (CFB) boiler based on the model developed earlier by the authors was applied to simulate the operation of a 12 MW CFB boiler. The influences of the excess air ratio, primary air ratio, coal particle size distribution, coal properties (ash content and volatile content) and Ca/S ratio on the boiler operation were analyzed. The results showed that the model simulation may be applied to the optimum design and economic operation of the CFB boiler.
文摘Recently, a large amount of circulating fluidized bed boiler ash (CFBA) and desulfurization gypsum (DSG) has been produced, and it is essential to develop technology to utilize them. These materials have CaO and SO</span><sub><span style="font-family:Verdana;">3</span></sub><span style="font-family:Verdana;">, which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> considered to be a stimulant for blast furnace slag (BFS). This study presents an experimental investigation of the compressive strength and heavy metal ions immobilization properties of cement-free materials comprising CFBA, BFS, and DSG. The feasibility of manufacturing foamed concrete using these materials was examined, and field test of foamed concrete was conducted. Experimentally, the flow, compressive strength, and heavy metal ions concentration were evaluated via inductively coupled plasma atomic emission spectroscopy (ICP</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">AES) of the paste and foamed concrete. The experimental investigation revealed the self-healing hardening ability of fluidized bed boiler ash. In addition, the compressive strength was increased with the increasing replacement rates of BFS and DSG in the CFBA paste, and the compressive strength of 14.6</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> - </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">17.2 MPa was recorded over 28 days of curing. From the result obtained, the feasibility of manufacturing foamed concrete with a foam volume </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">120 L, incorporating the aforementioned materials, is confirmed. It was also found that after 28 days of age, a 7.9-MPa compressive strength of the foamed concrete was attained, and heavy metal ions elution in this foamed concrete was also significantly reduced. Therefore, CFBA, BFS, and DSG could be used as a binder for the foamed concrete.
文摘Along with the rapid development of the industrialization process in our country in recent years, overall for industrialized production and construction in China put forward the new requirements. It is important to ensure that industrial production in the process of construction safety and quality, especially in recent years, our country the development of the circulating fluidized bed boiler equipment affected by the current state and factory industrial market. With the rapid development of science and technology in recent years, many new technologies and new equipment will be applied to the overall design of circulating fluidized bed boiler. This paper will be circulating fluidized bed boiler slag removal system in my company's actual application of a detailed introduction, clear circulating fluidized bed boiler slag removal system today's development.
文摘Under the national policy of vigorously promoting biomass fuel as clean fuel, biomass fuel as boiler fuel is the need of the development of the times. Combined with the current biomass fuel policy, this paper introduces the structural design characteristics of a circulating fluidized bed boiler burning biomass fuel, and explains in detail the design of each part of the boiler.
文摘With the continuous acceleration of social and economic development and the increasing expansion of boiler production scale, circulating fluidized bed boiler has become a necessary facility for industrial production. Affected by various factors, the water wall tube explosion of circulating fluidized bed boiler is very easy to occur during operation, which seriously affects the economic and safety benefits during the production, operation and construction of the enterprise. In view of this, taking 130t / h circulating fluidized bed boiler as an example, this paper puts forward the macro damage of the outlet nozzle of the circulating fluidized bed boiler, analyzes the macro and micro morphology of the fracture of the cracked pipe, and carries out micro hardness test and tensile test on the mechanical properties of the outlet nozzle. Finally, the reasons leading to the cracks in the export results are obtained, and the corresponding preventive countermeasures are formulated based on these reasons, in order to provide theoretical help for relevant staff.
文摘When large-scale circulating fluidized bed(CFB)boilers are working under a 1ow load condition.severe bed pressure swing often occurs and poses a serious threat to boiler stability and safety.Up to now,there are not enough theoretical studies on the bed pressure swing phenomenon.
基金supported by the key research and development program of Ningxia province of China(No.2018BCE01002)the national key research and development program of China(No.2018YFB0605401)+1 种基金the national natural science foundation of China(No.U20A20124)the innovation group project of Ningxia(No.2022AAC01001).
文摘Regulation of gas–solid flow is crucial for optimizing the operation efficiency of dual-circulating fluidized beds that are considered to be the most appropriate type of chemical-looping reactors. Herein, a computational particle fluid dynamics method was employed to simulate the gas–solid flow in a 3-MWth dual-circulating fluidized bed used for chemical-looping combustion and gasification. The influence of structural difference between units on particle residence time was determined. The multi-parameter control mechanism of pressure, particle circulation, and particle residence time in a whole-loop system was investigated. Results revealed that under stable particle circulation, the particle residence time in the fuel reactor is much longer than that in the air reactor. The axial forces on the particles are reduced upon increasing particle density and size, leading to particle accumulation in the dense-phase zone. When the particle properties are stable, increasing the fluidizing gas flow rates by the same proportion leads to identical pressure drops on the involved two loop seals, which cause symmetrical alterations in the particle circulation rate between the air and fuel reactors. The dual-circulating fluidized bed exhibits certain multi-condition adaptability, which is limited by the stock bin volume. Overall, this study is beneficial for effective and economical optimization of the operation of chemical-looping dual-circulating fluidized beds.
文摘The supercritical circulating fluidized bed(CFB)boiler,which combines the advantages of CFB combustion with low cost emission control and supercritical steam cycle with high efficiency of coal energy,is believed to be the future of CFB combustion technology.It is also of greatest importance for low rank coal utilization in China.Different from the supercritical pulverized coal boiler that has been developed more than 50 years,the supercritical CFB boiler is still a new one which requires further investigation.Without any precedentor engineering reference,Chinese researchers have con ducted fundamental research,development,design of the supercritical CFB boilers independently.The design theory and key technology for supercritical CFB boiler were proposed.Key components and novel structures were invented.The first 600 MWe supercritical CFB boiler and its auxiliaries were successfully developed and demonstrated in Baima Power Plant,Shenhua Group as well as the simulator,control technology,installation technology,commissioning technology,system integration and operation technology.Compared with the 460 MWe supercritical CFB in Poland,developed in the same period and the only other supercritical one of commercial running in the word beside Baima,the 600 MWe one in Baima has a better performance.Besides,supercritical CFB boilers of 350 MWe have been developed and widely commercialized in China.In this paper,the updated progress of 660 MWe ultra-supercritical CFB boilers under development is introduced.
基金supported by the National Natural Science Foundation of China(52276110)。
文摘The co-combustion of low-rank coals through fluidized bed boiler(CFB)is an effective approach to enhance the level of resource utilization.To date,there has been a lack of investigation concerning the co-combustion kinetics and self-desulfurization characteristics of coal slime,coal gangue,and raw coal.In this study,we adopted multiple model-free and model-fitting methods to comparatively analyze co-combustion kinetics of blended coals on the basis of thermogravimetric data.Then,the sulfur balance and self-desulfurization of blended coals in the co-combustion were intensively investigated using a tube furnace set-up.The results reveal that in the presence of coal gangue in blended coals,the average activation energy(E_(a))falls within the range of 65.7 kJ/mol to 100.4 kJ/mol,as determined by four model-free methods.Conversely,in the absence of coal gangue,only the Flynn-Wall-Ozawa(FWO)and Friedman(FM)methods are deemed appropriate for calculating the average E_(a),yielding a value of 77.3 kJ/mol.The first order reaction model is confirmed to be reliable for analyzing the co-combustion kinetics of low-rank blended coals.Irrespective of the specific composition of the blended coal,a significant linear correlation exists between the Ea and the natural logarithm of the pre-exponential factor(lnA)within an extensive range of parameters.Moreover,the addition of coal gangue to the blended coal substantially enhances the self-desulfurization level,resulting in an increase from 25.7%to60.7%at 1073 K.The self-desulfurization efficiency exhibits a good linear relationship with both the mass ratio of coal gangue to coal slime and the molar ratio of calcium to sulfur.In a practical implementation,the optimal addition ratio of coal gangue is a trade-off between the self-desulfurization efficiency and the ignition capacity.
文摘This paper presents a set of general dynamic mathematical models for the combustion system of acirculating fluidized bi-bed boiler. The models fully consider the flow, combustion and heat transfercharacteristics, and describe the physical and chemical processes inside the bi-bed, including the gassolid flow, multiple particles combustion, gas chemical reactions, heat transfer and pressure balances,etc.
文摘A new Kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the principle of thermal equilibrium. A series of cold tests and hot tests were carried to optimize the structure and collocation of water-cooling tubes and showed that the method had the advantage of simple, accurate, reliable and good applicability for on-line "usage in a circulating fluidized bed boiler.
