Integrated Intelligent Energy

Assessment of alternative energy based on the source apportionment of PM2.5 in Hefei City

YOU Jia，WANG Runfang，MA Dawei，JIANG Shaoyi，ZHU Renbin，CHEN Jian，WANG Kefeng

2020, 42(1): 1-7.

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Based on the source apportionment of PM2.5 in Hefei in 2018, the contribution coefficient of civil bulk coal toρ(PM2.5) was figured out, and the effect of replacing bulk coal on air quality improvement was evaluated，which provided reference for alternative energy study. The results showed that the main sources of PM2.5 in Hefei included secondary pollution sources and primary pollution sources such as vehicle emission, soot dust, and crust dust. Their contribution to PM2.5 source were 37.80%, 33.70%, 19.60%and 8.90%，respectively. Since 2014 to 2018, 2802GW·h electricity, mainly in manufacturingof industrial(agricultural) industry,was replaced. After the implementation of alternative energy, the average concentration of PM2.5 decreased year by year, and concentrations in spring and winter were higher than those in summer and autumn.The concentration in summer was the lowest.The contribution of bulk coal to the concentration of atmospheric PM2.5 in 2014 and 2018 were 9.07 and 4.33μg/m3, respectively, which showed a 4.74μg/m3 decrease. The alternative energy is an effective way to improve the air quality of Hefei. Contribution of vehicle emissions to atmospheric PM2.5 should be highly valued in pollution control. More efforts should be made to promote alternative energy in transportation sector.

Development of processing technology for deactivated SCR denitration catalyst

〖WT4”BZ〗ZHANG Chunping1，QIN Chuan2，YANG Gang3，LIU Lu1，HU Yuelong4，CHENG Weiliang1

2020, 42(1): 8-14.

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To control the large amount of nitrogen oxides in the flue gas exhausted by coalfired boilers, selective catalytic reduction (SCR) denitration technology has been widely applied. The key of the technology is the performance of SCR denitration catalyst. SCR denitration catalyst with low activity but in favorable regeneration conditions can be recycled by regeneration treatment. Different or integrated regeneration techniques can be used on catalysts deactivated for different reasons.With the increase of regeneration times, SCR denitration catalyst as a consumable material will eventually become hazardous solid waste. The deactivated SCR denitration catalyst harmless treatment and recycling of metal elements are studied, and correspondent treatment techniques are put forward, which provides concepts and directions for future development.

Prognostic method for SRS equipment deterioration based on multivariate state estimation technology and similarity theory

WANG Yonglin，WANG Yun，JI Wanqing，SHEN Xianming，WANG Hua

2020, 42(1): 15-19.

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The safe and highefficiency operation of the key equipment in simultaneous removal of multipollutant system (SRS) is the guarantee for the whole system.When the equipment is deteriorating, there will be warning signal of onsite equipment state maintenance. This will not only prevent safety accidents, but also save cost in maintenance. A prognostic method for SRS equipment failure based on multivariate state estimation technique(MSET) and similarity theory is proposed. MSET is used to establish the historical parameter matrix of the equipment in normal state, and the similarity theory is used to perform a nonlinear operation on the correlation coefficients to estimate the value corresponding to the current state. Comparing the deviation between the two values above, if the deviation is greater than the preset threshold, the system will send out the degradation signal to remind operators and provide basis for equipment state maintenance. Based on the practical application result of a slurry circulating pump in a power plant,the prognostic method for SRS equipment failure based on multivariate state estimation technology and similarity theory is proved to be feasible for slurry circulating pump deterioration monitoring.

Research and application of environmental intelligent supervision system for thermal power plants based on “Internet +”

ZHANG Shanshan，WU Qiaoling，WANG Renlei，ZHU Yue

2020, 42(1): 20-24.

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Based on “Internet +”, data sharing, big data analysis, improved grayneural network(UGMN)model analysis and other technologies,continuous emission monitoring system(CEMS),environmentally distributed control system(DCS),programmable logic controller(PLC),thermal power plant plantlevel safety instrumented system(SIS)/management information system(MIS),grouplevel production marketing and realtime monitoring system,grouplevel fuel management system and other environmental protection database are established.These database that base on multiple data sources have developed a multidata sources environmental protection intelligent supervision system for thermal power plants which can realize realtime monitoring,trend analysis,intelligent prediction,report management,alarm management,etc.The system can comprehensively improve the health of environmental protection equipment and pollutant emission standards of thermal power enterprises,and provide a more efficient and intelligent platform for flue gas emission management and environmental supervision.

Study on synergistic removal effect on multiple pollutants made by WESP and ammonia desulfurization system

GAO Zhenglai1，ZHOU Guoshan1，SHEN Dong1，PAN Zhengqi1，ZHOU Wei1，XIN Xiaoying2，LI Yan2

2020, 42(1): 25-28.

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Ammonia desulfurization is of high desulfurization efficiency,and easy to operate.But it is has disadvantages such as ammonia escaping and(NH4)2SO4 aerosol forming.By analysis the removal efficiency on NOx,dust,NH3,droplets,SO3and other pollutants made by ammonia desulfurization system and wet electrostatic precipitator(WESP), their synergistic removal effect on typical pollutants above were systematically studied.The results show that the mass concentration of dust at the outlet of WESP is less than 10mg/m3，and 30%～40%NOx，90%SO3 and 80% droplets can be shrugged off, but only about 50% NH3 can be removed by the WESP and ammonia desulfurization system.Therefore,ultralow emission of dust and NOx can be achieved by WESPs and ammonia desulfurization systems,which has a significant effect on preventing aerosol forming caused by ammonia desulfurization.But their effect on ammonia escaping control still needs to be updated.

Fault recovery strategy for distribution network with isolated island and reconfiguration

LIU Xing，CUI Shuangxi

2020, 42(1): 29-34.

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In the fault recovery process of distribution network with distributed generation, power supply for some isolated circuits and loads can not be recovered. In order to solve these problems effectively, the depthfirstsearch algorithm should be improved to achieve the accurate partition for isolated islands. Then, according to the theory of loopbreaking operation, the binary particle swarm optimization algorithm was used to find the best switch combination in the residual distribution network, and to achieve fault reconfiguration. Finally, an case study on an IEEE33 bus system was made and validated by Matpower software. The load restoration rate was used to evaluate the recovery effect of the proposed scheme. By comparing the results of several cases, the effectiveness of the proposed scheme is verified.

Prediction method for weekly electricity consumption based on LSSVM algorithm

CHEN Tao1，LYU Song1，REN Tinglin1，XUE Xiaocen2，LUO Xingxiang1，LIU ming1

2020, 42(1): 35-40.

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With the deepening of the reform of electric power system and the vigorous development of electric power market, a more refined electricity consumption forecast is required by power generation enterprises in order to make a reasonable powergeneration plan and a market bidding strategy. A prediction method for weekly electric power consumption is proposed based on Least Squares Support Vector Machine (LSSVM) and shortterm electricity consumption forecast.Fully considering the periodicity and continuity of the electricity demand, weekly meteorological characteristics are added into the model input,which makes up for the shortcomings of traditional power forecasting models that only consider historical electricity quantity and cannot accurately predict shortterm power trends during great weather changes. The model proposed can meet the demand of a more refined electric quantity prediction in commercialized electric power market.It is of great practicability.

Design of floating photovoltaic power plants protection systems adapting to water level

ZHANG Li，ZHAO Jinke

2020, 42(1): 41-44.

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Floating photovoltaic power plants are generally applied in shallow and calm water areas.In order to expand the application range of floating photovoltaic power plants, a protective system which can adapt to the change of water level is invented. It mainly includes a protective steel structure and an adaptive winding chain system.The working principle of the system is introduced, and the strength calculation of the protective steel structure has considered water flow,wind and wave loads in type selection for the winding chain system.The adaptive chain winding system can make the protective steel structure and photovoltaic power plant automatically adapt to the change of water level,which ensures the safety of floating photovoltaic power plants.

An improvement scheme for busbar differential protection logic applied in singlesectionalized doublebusbar connection mode

FENG Guangjie，WANG Zhiyong，YAN Zhihui，HU Shasha，WANG Zhiwei，XIAO Feng

2020, 42(1): 45-49.

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Due to the incorrect tripping of nonfault busbar with the simulated disconnected bustie circuit current transformer(CT) during the pretesting process in the centralized network test for a 220kV busbar protection device, the limitation existing in big difference and small difference protection logic for singlesectionalized doublebusbar connection mode was proposed. After introducing the medium differential protection criterion, the protection ranges of three busbars were divided again in order to locate the specific fault busbar accurately. The differential protection range, calculation of the differential current, ratiorestraint characteristic equation and their specific applications in the protection logic in singlesectionalized doublebus connection mode were described. Through a simulation test, it was verified that adding medium differential protection criterion could effectively avoid maloperation, improve the quickness and sensitivity of the protection.

Experimental study on circulating cooling water treatment by microbiological method

SUN Zhenyu1,2,SHEN Mingzhong1

2020, 42(1): 50-53.

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In order to further save industrial circulating cooling water,circulating cooling water simulation test was carried out under working condition of the circulating cooling water system in a power plant.The variations of fouling thermal resistance and corrosion rate after adding composite microbial agent were monitored. Testing the conductivity and pH of the circulating water,it is proved that the variation rates of fouling thermal resistance and corrosion rate in the group II that added composite microbial agent were lower than that of group I without agent. It is indicated that the composite microbial agent works well in scale and corrosion inhibition.In the process of circulating cooling water treatment,composite microbial agent is greener,more efficient and more environmental than chemical doses.It can operates stably under high concentration ratio,which is of favorable economical benifits.

Application of ACMD in fault diagnosis for bearings

HUANG Shaowei

2020, 42(1): 54-57.

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Vibration signal which is of multiple components and nonstationary, is susceptible to noise interference in bearing fault diagnosis. In order to find a better method for bearing fault diagnosis, adaptive chirp mode decomposition (ACMD) and its application are studied.Firstly, the fault signal of bearings was decomposed adaptively into several components by ACMD. Secondly, the envelope spectrum of the component with biggest kurtosis was obtained by Hilbert transform and calculated. Finally, the fault was diagnosed by figuring out the characteristic frequency in the envelope spectrum. The method can extract the characteristic frequency of fault signals effectively and be of a good application prospect.

Application of fuel consumption difference analysis method in a supercritical pressure oncethrough boiler

WANG Zhiyong1，XU He2，ZHU Huimin3，GE Junpei1，XU Jing1

2020, 42(1): 58-62.

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In order to study the influence of boilerside large and small energysaving indicators on the fuel consumption of oncethrough boilers, analysis was made on a supercritical pressure oncethrough boiler. Boilerside performance tests on variables affecting fuelconsumption were made under 100%, 75%，and 50% load ratios, and the test results were used to calculate and analyze the consumption difference. It was confirmed that oxygen in discharged gas, exhaust gas temperature, unburned combustible in fly ash and slag,boiler efficiency and service power rate of power plant would affect the fuel consumption for powersupply. Through the data tracing on fuel consumption distribution, the impact of each consumption indicator on the fuel consumption on boiler side was analyzed, which could provide a reference for power plants in evaluating operation indexes and inspecting performance of supercritical units.

Design of onsite assembly and welding for Goupitan ship lift chamber

GENG Kepu

2020, 42(1): 63-67.

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The onsite assembly and welding for ship lift chamber is the key in the construction of ship lift.It is mainly restricted by the site limitation, poor construction conditions, tight construction period and other factors. It introduces a design of onsite assembly and welding for ship lift chamber including the modularized structure, hoisting in position, and setting of welding process. And it analyzes the design including technical characteristics, construction period and economy, safety and quality. The engineering practice indicates that the design can effectively ensure the construction quality, save the construction period, improve the work efficiency and guarantee the construction safety.

Cause analysis for the leakage of serpentinetube elbow in supercritical boiler economizer

LI Penggang

2020, 42(1): 68-72.

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To find out the leakage cause for the serpentinetube elbow(SA-210C steel) in a supercritical boiler economizer, macroscopic morphology observation, chemical component analysis, stress calculation, mechanical property test, and metallographic observation were implemented on the elbow samples.The results show that the chemical composition of SA-210C, tensile properties at room temperature and hardness of straight pipe met the requirements of relevant standards. There was no obvious abnormality in metallographic structure,but the hardness at cracking part was much higher than the upper limit, and the plasticity and toughness were significantly reduced. Since the tube wall pitted by the crushing of foreign material could not meet the designing requirement,there were microcracks at the bottom of the pit because of stress concentration. Under the action of pressure of medium and thermal stress during operation, the microcracks rapidly expanded and caused brittle cracking.

Field transformation of GIS circuit breaker in phasedivision operation

CHEN Yu1，HU Xiankuang2，WENG Xiaochuan3，YU Zicong4，SHAO Jingping1

2020, 42(1): 73-77.

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To prevent units from being damaged by open phrase operation, a power plant planned to update GIS circuit breakers in phasedivision operation into threephase mechanicallinked mechanism on site.Comparing two updating schemes and the operation situation of the unit, nondisassembling circuit breaker, partial adjustment on the size of material,and direct connection between the transmission part and the shaft of the circuit breaker must be taken in the updating scheme. The scheme has the advantages of low cost, nonstop busbar, arc extinguishing chamber with nondisassembling circuit breakers, convenience, flexible transformation and so on, which fundamentally eliminates the risk in the open phase operation of GIS circuit breakers in generator transformers,and ensures the safe operation.

Optimization of feedwater temperature of 1000MW double reheat units

XU Jiang，ZHAO Zhifa，LI Jun

2020, 42(1): 78-80.

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Increasing feedwater temperature is an important means to improve the thermal efficiency of unit operation cycle. Taking a 1000MW double reheat unit in a power plant as an example, by fully opening the steam admission control valve and bypass electric valve for the No.1 high pressure heater, the feedwater temperature at each load increased, and so did the flue gas temperature at denitrification device inlet. This operation mode can not only improve the economy of the unit, but also reduce the lower load limit of the denitration device.

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