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Table of Content

    25 January 2015, Volume 37 Issue 1
    Analysis of direct and indirect benefit of cogeneration power plants
    SONG Weiming, DING Junwei
    2015, 37(1):  1-4. 
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    Abstract:Direct and indirect benefits for a cogeneration power plant were defined in order to analyze the influence of heating on the cogeneration benefit. With the heatelectricity cost allocation method on the basis of heat capacity method, the benefits for the cogeneration power plant were calculated and analyzed. The results show that the heat and electricity benefits are not balanced; thus, electricity generation profits while heat supply incurred losses, and the absolute value of indirect heating benefit surpasses that of direct heating losses. It is also found that the indirect heating benefit increases with the heattoelectricity ratio and the incremental power utilization hours, but response little with fluctuating coal price.
    Experiment of feedwater oxygen treatment for 660MW supercritical unit
    YANG Yanke
    2015, 37(1):  5-8. 
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    Abstract:In a power plant, the reductive allvolatile treatment mode was adopted to treat the feedwater for the 660MW supercritical unit. The method has some disadvantages, such as higher scaling rate on the boiler heating surface and shorter chemical cleaning period of the boiler. In order to solve above problems, the experiment of feed water oxygen treatment for the unit was carried out. The experiment result shows that after oxygen treatment, the iron content of the watersteam system reduced obviously. In the feed water in inlet of the economizer, the iron content reduced from 8.0~13.5μg/L to below 1.0μg/L, the ammonia addition to the feed water reduced by 60%, the operation period of the precision treatment mixed bed lengthened by 2 to 3 times, and expected treated water quantity may be above 200000 tons in a period. The acid and alkali consumption for resin regeneration and selfused water in precision treatment mixed bed were reduced, and the discharge of waste regeneration liquid was reduced, which is useful for environment protection.
    Model identification of supercritical unit’s water supply system based on standard particle swarm optimization
    LU Xiaoling, MA Ping
    2015, 37(1):  9-12. 
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    Abstract:The feed water control is one of the important control systems of supercritical once through boiler. To establish an accurate mathematic model for water supply system of supercritical unit is an important foundation of ensuring water supply control quality. It is difficult to identify more accurate model by using of traditional identification method due to the complexity of supercritical once through boiler. Aiming at the features of the supercritical unit and the shortcoming of the traditional identification method, the standard particle swarm optimization method was used in water supply process identification. Taking a 600MW supercritical unit as example, based on the practical operation data of the power plant, a transfer function between the specific enthalpy of separator outlet (middle point) and the feedwater flow was established. The verification results show that the identification model can reflect actual operation curves accurately, which provide premise and assurance for design of water supply system of supercritical unit. Simultaneously, the rapidity and the accuracy of the identification model were improved by the particle swarm optimization method.
    Mathematic model of 660MW supercritical pressure once through boiler unit and simulation
    LI Meibao1,SHI Yitao2
    2015, 37(1):  13-15. 
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    Abstract:Based on analysis of thermodynamic characteristics of 600MW supercritical once through boiler unit, according to the energy conservation law, the mass conservation law and the momentum conservation law, a dynamic simulation model of 600MW supercritical once through boiler was established. Aiming at the feedwater disturbance, the power disturbance and the fuel quantity disturbance, the dynamic tests were carried out. The test results show that the model can simulate dynamic characteristics of practical unit accurately.
    Design and simulation of local control logic of runback
    KANG Lijie1, CHEN Wei2, LIANG Weiping1, MA Ping1
    2015, 37(1):  16-18. 
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    Abstract:There was some defect in primary air fan RB design of the 320MW coalfired unit of Qinhuangdao Thermal Power Plant, and after the RB signal occurred, the mills can not stop sequentially. Aiming at this problem, the design was improved. Under various operation conditions of the mills, the designed improving scheme was simulated by MATLAB simulation software. The result of the simulation test shows that the improved design scheme can satisfy the RB requirement of the unit, and the unit can operate safely and stably.
    Design and application of newtype automatic test system of relay protection equipments
    YAO Liang, CHEN Shi, ZHANG Yonggang
    2015, 37(1):  19-21. 
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    Abstract:The manual test and automatic test of the relay protection equipments were compared. The demand features for the automatic test system in development of recent intelligent relay protection equipments were analyzed. Based on this, a new comprehensive automatic testing scheme was proposed and realized. Using the new automatic test system, it is possible to realize comprehensive automatic test of the intelligent relay protection equipments. The use process of the automatic test system was expounded, and the design idea of the system in automation, visualization and intelligence was introduced in detail.
    Analysis on design of selfpropelled hydraulic winch
    LI Qingmei, ZHENG Yi, YANG Junning, ZHOU Limin, WEI Yunlong
    2015, 37(1):  22-24. 
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    Abstract:The concept and technical requirements of the selfpropelled hydraulic winch were introduced. The main structure, the working principle of the hydraulic system and the characteristics of the winch were analyzed. The engineering application of the winch shows that the performance of the selfpropelled hydraulic winch is excellent, and its indexes can meet the design requirements.
    Analysis on reasons of abnormal coal feeding rate of CS2024 electronic weighing coal feeder and treatment
    XIAO Ronghui, GUAN Feiran, YU Kang
    2015, 37(1):  25-29. 
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    Abstract:In operation of CS2024 electronic weighing coal feeder, a problem of abnormal coal feeding rate occurred, which deteriorated performance of the combustion control system directly. The output power of the unit was limited, and the unit operation safety was affected. The reasons of abnormal coal feeding rate were analyzed. The preventive measures were proposed, and better result was obtained.
    Analysis on reasons of vibration of circulating water pump twospeed motor of 1000MW unit and treatment
    CAO Jingfang
    2015, 37(1):  30-33. 
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    Abstract:The YKSL3650-16/2600 type circulating water pump motor of a domestic 1000MW unit was reformed into twospeed motor. After the reformation, the larger vibration occurred in stator part of the motor. According to diagnosis, it was determined that the reason of the vibration is 100Hz resonance. Some methods were used to reduce the unbalance of the magnetic potential, and the vibration problem of the motor was solved.
    Analysis on reasons of higher temperature of bearing bush of horizontal shaft mixed flow water turbinegenerator unit and treatment scheme
    ZHENG Jianfeng
    2015, 37(1):  34-36. 
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    Abstract:In a hydropower station, after the horizontal shaft mixed flow water turbinegenerator unit was put into operation, the temperature of the thrust pad and the guide bearing shoe increased abnormally. The reasons of the higher temperature of the bearing bushes were analyzed. The treatment scheme was proposed. The scheme was implemented, and the chronic disease of higher bearing bush temperature and even bearing bush burning was solved. The ability of the equipment to operate stably was improved.
    Analysis and reformation of brake control circuit of builders hoist
    DENG Xiangmei
    2015, 37(1):  37-39. 
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    Abstract:The new requirements of brake control circuit of builders hoists specified in the new national standard GB 26557—2011 “Builders Hoists for Persons and Materials with Vertically Guided Cages” was introduced. The problems existing in brake control circuit of present builders hoist were analyzed. The brake control circuit of builders hoist was analyzed, and the reformation measures were proposed. The reformed brake control circuit of the builders hoist can meet the requirements of the new national standard.
    Formation reasons of ammonium bisulfate in SCR flue gas deNOx process and cleaning method
    ZENG Biqun1, YAO Yougong1, YANG Bo1, WANG Lele2
    2015, 37(1):  40-41. 
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    Abstract:The formation reasons and the characteristics of the ammonium bisulfate (ABS) formed by SCR flue gas deNOx system in air preheater cold end were analyzed. An off-line hot water washing method to clean the ammonium bisulfate dirt was proposed. The process flow and the operation parameters of the cleaning method were expounded, and the matters needing attention in cleaning process were pointed out. The practical use shows that the result of the cleaning method is favorable.
    Optimization of cleaning chain system of aircooled drytype slag extractor and its application
    MA Xingcai1, WANG Kaiyun2, SU Fuqiang3
    2015, 37(1):  42-44. 
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    Abstract:There were defects in the original cleaning chain system of the aircooled drytype slag extractor of thermal power unit, which include the serious abrasion, the frequent taking off the chain, the high operation cost and other faults. The reasons of above problems were analyzed, and an optimization scheme was proposed. The operation conditions of the cleaning chain system before and after optimization were compared. The comparison result shows that the operation cost of the optimized cleaning chain system was decreased effectively, and the maintenance workload of the system was reduced significantly.
    Discussion of implementation details of idle boiler preservation using ammoniahydrazine passivation drying method
    CAO Deping
    2015, 37(1):  45-46. 
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    Abstract:The protection mechanism of ammoniahydrazine passivation drying method was introduced. It is difficult to keep the mass concentration of the hydrazine in required value during idle boiler preservation. Aiming at above problem, some measures, such as to adjust the equipment function, to improve the chemicals feed mode and others, were proposed. Taking the supercritical unit of Hunan Huadian Changsha Power Generation Company Limited as example, the implementation key points of the idle boiler preservation were given. The tubecut inspection data during overhaul show that the preservation result is favourable.
    Analysis on reasons of larger measurement deviation of main steam flow of 330MW unit and countermeasures
    YANG Ruihan
    2015, 37(1):  47-48. 
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    Abstract:The measurement deviations of the main steam flow and the feed water flow of a 330MW thermal power unit were analyzed. The main steam flow function was amended, and the temperature correction was done for the feed water flow. The deviations were eliminated, and the unit performance in energy saving and consumption reducing was improved.
    Optimization of coordinated control system of ultra supercritical unit in Wuhu Power Generation Company
    LI Zhi
    2015, 37(1):  49-50. 
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    Abstract:Taking the units No.1 and No.2 of Anhui Huadian Wuhu Power Generation Company Limited as examples, aiming at the leftover problems in units commissioning process and the problems existing in operation, the concrete optimized strategy was given. After the strategy was implemented, the units operate safely and stably, and the economic benefit and the social effect are obvious.
    Application of valve diagnosis technology and expectation of diagnosis equipment domesticization
    WANG Shuhong1, BAI Bing2, LU Yandong2, CHEN Yunlong2, WANG Lan1
    2015, 37(1):  51-52. 
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    Abstract:The application of valve diagnosis technology in construction, operation and maintenance of nuclear power stations was introduced. The core technical parts, such as stress transducer and data acquisition unit, were introduced emphatically. The application prospect of the valve diagnosis technology in thermal power generation, metallurgy, petrochemical industry and other industries was analyzed. The capability of domestic enterprises in development and manufacturing of valve diagnosis devices was affirmed, and some suggestions were given for promoting domesticization of the valve diagnosis equipments.
    Analysis on reasons of faults of power distribution network and prevention measures
    HOU Rui, XU Jing, XU Shengzhu
    2015, 37(1):  53-54. 
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    Abstract:The reasons causing faults of power distribution network, including the environmental factors, the human factors and the equipment factors, were introduced. The features of the common faults were analyzed. Some improvement measures were adopted, which include the distribution network condition based maintenance management, the distribution network spacetime dynamic management, the distribution network professional engineering management, the supervision of power distributing equipments and utilization of new technologies and new equipments. The faults of the power distribution network were decreased, and the power supply reliability was improved.
    Analysis on false action of main transformer differential protection responding outside area fault caused by twopoint grounding of secondary current circuit
    LIAO Hongtao
    2015, 37(1):  55-57. 
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    Abstract:An 110kV line is one of output lines of the 330kV main transformer. When a ground fault of the 110kV line occurred, the differential protection of the main transformer tripped incorrectly. The fault record figure was investigated, and it was found that when the differential protection device tripped due to the outside area fault, the phase B current increased abnormally. The CT secondary circuit site was inspected, and it was found that there was two points ground phenomenon in the secondary circuit phase B. It was analyzed that when the CT secondary circuit phase B grounded through two points, why the outside area fault can cause the differential protection of the main transformer to trip incorrectly. The preventive measures were proposed.
    Application of dynamic steel ball elimination technology in ball mill
    LI Jianmin1, PAN Xinlong2
    2015, 37(1):  58-61. 
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    Abstract:Taking the boiler No.1 ball mills of production center of PetroChina Daqing Petrochemical Company as example, the automatic disabled ball elimination technology was adopted to optimize the control of ball mill DTM350/600. The automatic elimination device was installed in the outlet of the mill, which can eliminate the disabled steel balls and the sundries of the ball mill online. The disadvantages of traditional screening method were overcome. At the same time, the energy consumption of the ball mill was reduced, the output capacity of the ball mill was increased, the service life of the structural parts of the mill was lengthened, and the boiler slag was avoided. The safety and the stability of the production process were ensured.
    Selection of preparation technology of denitration deoxidizer using ammonia water as raw material
    ZHANG Yuming
    2015, 37(1):  62-63. 
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    Abstract:There are several typical technologies to evaporate ammonia water to prepare denitration deoxidizer, which include the steam stripping, the hot air evaporation, the hot flue gas evaporation in situ and others. These technologies were introduced. The principles, the advantage and the disadvantages of each technology and the matters needing attention were expounded. The results in this paper provide reference for selecting of denitration deoxidizer preparation technology.
    Application of leachate backejecting treatment technology in garbage incineration power plant
    ZHAO Xiaofeng
    2015, 37(1):  64-67. 
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    Abstract:A leachate backejecting treatment technology was introduced. The technology is suitable for mechanical gratetype garbage incinerating boiler. The first step is to pretreat the garbage leachate, the sequent step is to use compressed air to atomize the pretreated leachate and eject it into furnace to incinerate. The technology system is simple and reliable and has strong capability to adapt to load fluctuation. The backejecting incineration technology is true harmless treatment and does not cause secondary sewage discharge. The costs of the construction, installation and operation of the garbage backejecting treatment system are lower. The technology system was applied in multiple garbage incineration power plants successfully and is worth of popularization in the cities where the caloric value of the garbage is higher.
    Influence of blending combustion of east Junggar coal on boiler operation
    LI Peng, ZENG Qi, REN Jianping, YU Liyang
    2015, 37(1):  68-70. 
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    Abstract:The features of the east Junggar coal include the low price, the high volatiles, the high caloric value and the low ash fusion point. To fire the east Junggar coal may cause serious coking in boiler and threaten safe operation of the boiler directly. In the Owned Power Plant of Xinjiang Xinte Energy Company Limited, the scientific theory was combined with practical experiences to direct the blending combustion of the east Junggar coal, and some anticoking measures were adopted. The flue gas temperature in the furnace outlet was reduced effectively, the boiler coking was lightened, and the safe operation of the boiler was ensured.
    Analysis on power consumption rate of condensate pump and optimization reformation
    ZONG Xudong
    2015, 37(1):  71-72. 
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    Abstract:The problem about high power consumption rate of condensate pumps in power plants of Huadian Power International Corporation Limited was introduced. The statistics of practical power consumption rate of condensate pumps of five classes of power units were given. The reasons of high power consumption rate of the condensate pumps were found. The measures of operation optimization and frequency conversion renovation were adopted, and favorable result was obtained.
    Application of SO3 flue gas conditioning system in Qingshuichuan Power Plant
    ZHANG Hui
    2015, 37(1):  73-75. 
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    Abstract:Taking the Qingshuichuan Power Plant project phase II as example, the principle, the process flow and the operation features of the flue gas conditioning system were introduced. The technological economic performance of several methods, such as enlargement of the size of the electrostatic precipitator body, the installation of bagtype dust remover, the flue gas conditioning by conditioning agent and the flue gas conditioning by water, were compared. The features of SO3, NH3, Na2CO3 and phosphoric acid used as conditioning agent were analyzed. At last, the SO3 flue gas conditioning system was selected, and ideal dust removal effect was obtained.