Large size utility boilers develop rapidly in China, both their reliability and economics have reached better level. The operating situations of various existing boilers on the basis of different coals are analyzed, i...Large size utility boilers develop rapidly in China, both their reliability and economics have reached better level. The operating situations of various existing boilers on the basis of different coals are analyzed, it is held that, the notable energy imbalance of furnace exit, ever existing in the tangential firing boilers has been solved, with comparatively lower NOX emission concentration of gained. The higher NOX emission concentration and furnace slagging etc. problems existing in wall firing boilers are notable. The comprehensive analysis shows that, it is appropriate to choose lower furnace volume heat release rate and higher flame height in the type selection design of boilers, and sufficient margin should be kept in the selection of coal pulverizing mills.展开更多
Low-NOX combustion retrofit is performed by adopting staged combustion technology for a 600 MW utility boiler with a four-corner tangential firing system. The emission data of NOX before and after retrofit are compare...Low-NOX combustion retrofit is performed by adopting staged combustion technology for a 600 MW utility boiler with a four-corner tangential firing system. The emission data of NOX before and after retrofit are compared and analyzed. The test results show that the emission concentration of NOX decreases obviously after the low-NOX retrofit. Additionally, the emission of NOX decreases by nearly 50% when the unit load is higher than 350 MW. It can also be concluded that the emission of NOX is influenced significantly by the amount of SOFA, the damper opening of auxiliary air, the differential pressure between the secondary air windbox and the furnace, and so on.展开更多
Glass-ceramics obtained from the electric arc furnace molten slag of incinerator fly ash was produced by applying nucleation and crystallization through heat treatment process. The effects of nucleating agent （TiO2 a...Glass-ceramics obtained from the electric arc furnace molten slag of incinerator fly ash was produced by applying nucleation and crystallization through heat treatment process. The effects of nucleating agent （TiO2 and Cr2O3） on the crystallization kinetics and heat treatment schedule of the slag were investigated. The results show that the nucleating agents changed the crystallization phase and morphology of the obtained glass-ceramics. The optimum heat treatment schedule of the glass with TiO2 was determined as nucleation at 952 K for 1.5 h and crystal growth at 1 258 K for 1.5 h, while those values with Cr203 were estimated at 971 K for 2 h and at 1 238 K for 2 h. TiO2 acting as nucleating agent could decrease the activation energy of the slag and shorten the total thermal treatment time in comparison with Cr2O3. The glass-ceramics obtained under the optimum heat treatment condition was environmentfriendly and had remarkable physical/mechanical properties and chemical durability.展开更多
The paper deals with development and application the numerical model for solution of processes at combustion chamber of the thermal power plant boiler. Mathematical simulation is based on solution of physical and chem...The paper deals with development and application the numerical model for solution of processes at combustion chamber of the thermal power plant boiler. Mathematical simulation is based on solution of physical and chemical processes occuring at burning pulverized coal in the furnace model. Three-dimensional flows, heat and mass transfer, chemical kinetics of the processes, effects of thermal radiation are considered. Obtained results give quantitative information on velocity distributions, temperature and concentration profiles of the components, the amount of combustion products including harmful substances. The numerical model becomes a tool for investigation and design of combustion chambers with high-efficiency and reliable operation of boiler at thermal power plants.展开更多
Pulverized coal-fired(PCF) boilers were first and foremost intended to fire pulverized hard or brown coal. However, biomass co-firing has become a fairly common practice in the Polish power generation system and many ...Pulverized coal-fired(PCF) boilers were first and foremost intended to fire pulverized hard or brown coal. However, biomass co-firing has become a fairly common practice in the Polish power generation system and many existing boilers have been modernized to serve this purpose. This paper presents calculations of the coefficient of thermal efficiency of the boiler heating surfaces and of the time needed for complete reconstruction of deposits on the second-stage steam reheater(RHII) of an OP-380 boiler with the output of 380×10~3 kg/h. The boiler was equipped with a purpose-designed installation of direct feeding of biomass. The main co-fired fuels were wood and sunflower husk pellets. Intense formation of deposits on the steam reheater tubes and problems related to a reduction in the diameters of the tubes were identified during the power unit operation.展开更多
文摘Large size utility boilers develop rapidly in China, both their reliability and economics have reached better level. The operating situations of various existing boilers on the basis of different coals are analyzed, it is held that, the notable energy imbalance of furnace exit, ever existing in the tangential firing boilers has been solved, with comparatively lower NOX emission concentration of gained. The higher NOX emission concentration and furnace slagging etc. problems existing in wall firing boilers are notable. The comprehensive analysis shows that, it is appropriate to choose lower furnace volume heat release rate and higher flame height in the type selection design of boilers, and sufficient margin should be kept in the selection of coal pulverizing mills.
文摘Low-NOX combustion retrofit is performed by adopting staged combustion technology for a 600 MW utility boiler with a four-corner tangential firing system. The emission data of NOX before and after retrofit are compared and analyzed. The test results show that the emission concentration of NOX decreases obviously after the low-NOX retrofit. Additionally, the emission of NOX decreases by nearly 50% when the unit load is higher than 350 MW. It can also be concluded that the emission of NOX is influenced significantly by the amount of SOFA, the damper opening of auxiliary air, the differential pressure between the secondary air windbox and the furnace, and so on.
基金Supported by the National Natural Science Foundation of China(No.51378332 and No.20806051)Science and Technology Project of Housing and Urban-Rural Ministry(No.2014-K4-014)Chinese Postdoctoral Science Foundation(No.2013M530872)
文摘Glass-ceramics obtained from the electric arc furnace molten slag of incinerator fly ash was produced by applying nucleation and crystallization through heat treatment process. The effects of nucleating agent （TiO2 and Cr2O3） on the crystallization kinetics and heat treatment schedule of the slag were investigated. The results show that the nucleating agents changed the crystallization phase and morphology of the obtained glass-ceramics. The optimum heat treatment schedule of the glass with TiO2 was determined as nucleation at 952 K for 1.5 h and crystal growth at 1 258 K for 1.5 h, while those values with Cr203 were estimated at 971 K for 2 h and at 1 238 K for 2 h. TiO2 acting as nucleating agent could decrease the activation energy of the slag and shorten the total thermal treatment time in comparison with Cr2O3. The glass-ceramics obtained under the optimum heat treatment condition was environmentfriendly and had remarkable physical/mechanical properties and chemical durability.
基金funded by the Ministry of Education and Science of Kazakhstan Republic,№0112РК01095support from the Technology Agency of the Czech Republic in the frame of the Competence Centre Advanced Technology of Heat and Electricity Output,No.TE01020036
文摘The paper deals with development and application the numerical model for solution of processes at combustion chamber of the thermal power plant boiler. Mathematical simulation is based on solution of physical and chemical processes occuring at burning pulverized coal in the furnace model. Three-dimensional flows, heat and mass transfer, chemical kinetics of the processes, effects of thermal radiation are considered. Obtained results give quantitative information on velocity distributions, temperature and concentration profiles of the components, the amount of combustion products including harmful substances. The numerical model becomes a tool for investigation and design of combustion chambers with high-efficiency and reliable operation of boiler at thermal power plants.
文摘Pulverized coal-fired(PCF) boilers were first and foremost intended to fire pulverized hard or brown coal. However, biomass co-firing has become a fairly common practice in the Polish power generation system and many existing boilers have been modernized to serve this purpose. This paper presents calculations of the coefficient of thermal efficiency of the boiler heating surfaces and of the time needed for complete reconstruction of deposits on the second-stage steam reheater(RHII) of an OP-380 boiler with the output of 380×10~3 kg/h. The boiler was equipped with a purpose-designed installation of direct feeding of biomass. The main co-fired fuels were wood and sunflower husk pellets. Intense formation of deposits on the steam reheater tubes and problems related to a reduction in the diameters of the tubes were identified during the power unit operation.
