2018年03期目次

  • Application and status of supercritical carbon dioxide in power industry

    CAO Lei;SUN Dengke;LI Weicheng;CHEN Yang;ZHOU Songrui;Dongfang Boiler Group Co.,Ltd.;

    In order to realize the global goals of adjusting,optimizing the industrial structure,enhancing the energy efficiency,saving energy and reducing emission,the basic characteristics of sCO_2 were overviewed.Four aspects,i.e.,electricity generation using carbonaceous material,nuclear reactor,solar power and waste heat recovery,concerning the sCO_2's application in power field were described.The current research,experiment and demonstration were summarized. The bottle-neck,technical challenge and future research aspects of developing sCO_2 were proposed.Results show that all different sCO_2 cycling systems have critical problems that have not been totally solved,such as corrosion of sCO_2 to materials,system design and type-choosing of sCO_2 cycling system,design and manufacture of high-efficiency microchannel circuit heat exchanger,research and development of new-type sCO_2 turbine,compressor and gas turbine. The sCO_2 is able to be widely used in power industry,military and ship project after improvement and breakthrough of material,design of high efficiency cycling system,fabrication of key equipment.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 161K]

  • Characteristics and cleanliness class of coal seam in Baorixile Open-pit Coal Mine

    GUO Xuying;LI Ying;DONG Yanrong;XING Jingwei;LI Zhennan;College of Science,Liaoning Technical University;College of Mining Engineering,Liaoning Technical University;

    In order to use the coal of Baorixile Open-pit Coal Mine reasonably and cleanly in Chenqi coalfield of Inner Mongolia Autonomous Region,the physical and the petrographical properties of coal were analyzed based on the geological background of the whole region and the basic situation of the coal-bearing strata in the Damoguaihe Formation. Their feasible industrial properties and usage were determined.The cleanliness of the mining area coal seam was drew primarily from the aspects of ash,sulfur,As and Cl.The results show that durain and semidull coal are the main lithotypes of the 12,21,31 and 32+3 coal seam.Huminite and inertinite are the main organic maceral of the mining area coal.The coal is low ash,high volatile,medium and high fixed carbon,extra low sulfur,extra low chlorine,extra low ~ low phosphorus and first grade arsenic.By analyzing the process properties of raw coal,it is found that the mine seam is main No. 2 lignite,which belongs to medium-high calorific value,high tar yield,medium slagging coal.The 21 coal is easy to be ground,and 12 and 31 coal are extremely easy to be ground and refractory coal.The cleanliness class of the mining area coal is Ⅱ,which belongs to the better clean coal.The coal in the mining area can be used as coking,steam coal and civilian coal.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 127K]

  • Experimental study on sedimentation characteristics of slime water

    FENG An'an;ZHOU Wei;ZHU Jinbo;ZHANG Yong;School of Materials Science and Engineering,Anhui University of Science and Technology;

    To solve the problem of worse settlement effect of coal slime water in Sanhejian coal separating plant,the coal slime with high concentrating feeding was studied.Based on the analysis of properties of coal slime,a series of slime water settlement experiments with different kinds of coagulants and flocculants were carried out.The effect of concentration of slime water,coagulant and flocculant dosage on the settlement effect of slime water was systematically investigated.Results show that the low metamorphic grade of raw coal,the finer particle size of coal slime and the existence of clay minerals increase the difficulty of slime water treatment.PAC and PAM with 10 million molecular weights are the best combination of drugs,which optimal dosage are 780 g/t and 15 g/t respectively,when the slime water concentration is 70 g/L.The settlement effect of slime water is the best in this condition with supernatant turbidity 18 NTU and settlement speed 11.16 cm/min.The dosage of flocculant and coagulant have a significant influence on the settlement effect of slime water,and the change of slime water concentration in small range has no obvious effect on that.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 168K]

  • Preparation and evaluation of lignin-based dispersant for coal water slurry

    YANG Chun;CHEN Hui;XU Yinglu;WU Jiahua;Dongfang Electric Corporation;

    In order to reduce preparation cost of dispersant for coal water slurry(CWS),increase performance of lignin-based dispersant and realize resourceful utilization of alkaline waste liquor,CWS dispersant DLS was prepared by chemical modified alkaline lignin or alkaline waste liquor as the main raw material.The difference between DLS and alkaline lignin in acid group content,heavy molecular weight and thermal decomposition temperature were contrasted. Typical lignite,bituminous coal,anthracite and semi-coke were used to prepare CWS,and effect of DLS and lignin-based dispersant on pulping property of CWS was examined.Results show that total acidic group content of DLS increases from 0.35 mmol/g to 1.70 mmol/g,heavy molecular weight increases from 2 550 to 16 310,and thermal decomposition temperature is increased to 300 ℃ after chemical modification.Under the same condition,the optimized addition of naphthalene dispersant to four kinds of coals is 0.5%.The optimal addition of DLS to Baori lignite and Shenmu bituminous coal are 0.5%,and that to Xingyi anthracite and Shenmu semi-coke are 0.3%,which is 40% lower than that of naphthalene dispersant,indicating that DLS has a better performance.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 147K]

  • Influence of coal particle size and moisture content on pyrolysis characteristics of Baiyinhua lignite

    WANG Yuli;CHEN Shuimiao;SUN Baolin;LIAN Xinpei;ZHANG Hongwei;XIAO Lei;WU Daohong;Shenwu Technology Group Corp;Pyrolysis and Quality Engineering Technology Research Center of Low Rank Coal and Organic Waste in Beijing;

    In order to obtain the optimal process parameters,the Baiyinhua lignite was pyrolyzed at 900 ℃ in a regenerative downer reactor.The influence of lignite particle size and moisture content in lignite on the yield of pyrolysis product and characteristics of gas was analyzed.Results indicate that with the lignite particle size increasing from 0 to 6 mm,yield of pyrolysis gas decreases.The lignite with particle size of 0-6 mm is suitable for pyrolysis,because the yields of pyrolysis gas are greater than 35%.For the lignite particle size < 3 mm,the yield of pyrolysis water and pyrolysis gas increase,and the yield of char decreases with the rise of moisture content from 15. 10% to25. 03%.Thus,the lignite with higher moisture content in the range of 15. 10% to 25. 03% is suitable for pyrolysis. With the raising of moisture content,the drying efficiency could be remarkably enhanced,and the soot amount could be reduced.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 177K]

  • New technology of coal-natural gas co-gasification in entrained-flow bed

    XU Hongwei;LIN Yian;ZOU Tao;ZHENG Yalan;WEI Sunchang;Northwest Research Institule of Chemical Industry Co.,Ltd.;Xi'an Origin Chemical Technologies Co.,Ltd.;

    Coal-natural gas co-gasification technology is an efficient comprehensive energy conversion technology that realizes the complementary advantages of different processes. The influence of gasification temperature,gasification pressure,natural gas/coal and water coal slurry concentration on main indexes of coal-natural gas gasification was studied with coal-natural gas cogasification test device.By analyzing main gas composition,hydrogen-carbon ratio(H_2/CO) and methane content in the synthetic gas,the conditions of coal-natural gas cogasification test was optimized,and the coal-natural gas cogasification optimization test was carried out.The results show that the suitable reaction conditions for coal-natural gas cogasification are gasification temperature 1 300-1 400 ℃,natural gas/coal 0.75-1.50 Nm3/kg,coal slurry concentration 58%-61%.In conditions of pulping concentration 59%,coal intake 18 kg/h,natural gas/coal 0.94 Nm3/kg,gasification temperature 1 350 ℃,gasification pressure 0.5 MPa,the production of synthetic gas,H2+CO content,methane content and H2/CO are 46.06 Nm3/h,88.64%,0.66% and 1.23,respectively using Xiwan coal as raw material. It shows that coal-natural gas co-gasification technology is a highly efficient gasification technology,that is beneficial to large-scale industrial application.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 225K]

  • Experimental study on CH4 and CO2 mixture separation

    LI Xuefei;GUO Haoqian;Coal Chemistry Branch of China Coal Research Institute;Beijing Key Laboratory of Coal Based Carbon Materials;State Key Laboratory of Coal Mining and Clean Utilization;

    In order to clarify the effect of home-made carbon molecular sieve adsorbent on the separation of CH_4/CO_2 mixture,a self-made carbon molecular sieve adsorbent was used to separate CH_4/CO_2 mixture by a pressure swing adsorption process.The effects of process parameters,such as adsorption pressure and adsorption time,on biogas separation efficiency were studied.The advantages of self-made carbon molecular sieve adsorbent in biogas separation were verified by comparison with activated carbon and carbon molecular sieve adsorbent.The results show that with the increase of adsorption time,the separation effect increases firstly and then decreases.The optimal adsorption time is 180 s.With the increase of adsorption pressure,the separation effect increases firstly and then decreases.The optimal adsorption pressure is 600 k Pa.Home-made carbon molecular sieve adsorbent has the advantages of good separation effect,high methane recovery and stable product gas concentration.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 221K]

  • Kinetics of hydrocracking for heavy coal tar oil

    LI Weilin;HUANG Peng;ZHAO Yuan;MAO Xuefeng;Coal Chemistry Branch of China Coal Research Institute;State Key Laboratory of Coal Mining and Clean Utilization;National Energy Technology & Equipment Laboratory of Coal Utilization and Emissions Control;

    To study the kinetics of hydrocracking for heavy coal tar oil,the experiments were carried out in a 100 m L high heating rate autoclave reactor.Heavy Xinjiang coal tar oil was hydrocracked with highly dispersed Fe series catalyst in condition of hydrogen pressure 10 MPa,stirring speed 350 r/min,temperature 430-460 ℃,in different reaction time.Hydrocracking of heavy coal tar oil shows strong character of sequential reaction.With the increase of tar oil conversion,hydrogen consumption and gas yield increase to 2.7% and 8.3% respectively,at the same time,oil yield increases to 87.0%.However,the gas selectivity increases constantly.In contrast,the oil selectivity reaches to the maximum 91.5% when the conversion is 57.2%,and then decreases.It is thought that in later stage of sequential reaction,some oil product convertes into gas product.Thus,the proper reaction temperature and time are very important.The first order kinetics can fit the results of hydrocracking reaction for heavy coal tar oil well with Ea = 434.7 k J/mol,which is higher than many residuum hydrocracking reactions.The dispersed Fe catalyst can provide active H and stabilize radicals,and the hydrocracking of heavy coal tar oil is essentially thermal activation reaction.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 210K]

  • Experimental study on compatibility determination method of coal tar

    LI Peilin;Coal Chemistry Branch of China Coal Research Institute;

    In order to ensure stability of the suspension bed hydrogenation unit,an improved method for measuring coal tar compatibility was put forward.A high temperature coal tar was mixed with three kinds of heavy oil according to 1 ∶ 1 respectively to prepare three mixed tar samples: C(A+>260 ℃ heavy oil),D(A+>280 ℃ heavy oil) and E(A+>300 ℃ heavy oil).The initial asphaltene flocculation points of C,D,E were measured by the photometer method,and the compatibility data of the three samples were obtained.The influence of heavy oil cutting points on the compatibility of the samples were discussed.At the same time,the stability parameter method was investigated,and the results were compared and verified.The results show that the compatibility of coal tar obtained by the two methods is consistent,which can be used to determine or predict the compatibility of coal tars.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 182K]

  • Effect of aromatic co-carbonization on formation of coal-based mesophase carbon microbeads

    WANG Guangyao;YAN Bingfeng;Coal Chemistry Branch of China Coal Research Institute;State Key Laboratory of Coal Mining and Clean Utilization;

    In order to study the influence of aromatic co-carbonization on preparation of mesophase carbon microbeads(MCMB),medium temperature asphalt was used as raw material,and anthracene oil enriched aromatic components were added to prepare MCMB with thermal condensation.The structure of medium temperature asphalt was characterized by IR(infra-red) spectrum,and MCMB was analyzed by elemental analysis,polarizing microscope and particle size analysis.The influence of anthracene oil on yield,atomic ratio of C/H and particle size of MCMB was investigated detailedly.The results show that the optimized conditions for MCMB preparation are temperature at 440 ℃and reaction time 8 h. Anthracene oil can effectively reduce the viscosity of reaction system,and promote the growth and melting of microbeads.Addition of anthracene oil can effectively improve the yield of MCMB,and make the range of particle size narrow.However,excessive addition of anthracene oil can reduce the density of original quinoline insoluble,which prevents the polycondensation reaction. When the amount of anthracene oil is 5%,the yield of MCMB is 52.59%,atomic ratio of C/H is 1.91,and the diameter of D10 and D90 are 5.795μm and 41.202 μm respectively.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 279K]

  • Research on the correlation between specific surface area and iodine adsorption value of coal-based activated carbon

    JIA Jizhen;ZHANG Huirong;PAN Zipeng;GUO Yanxia;CHENG Fangqin;Institute of Resources and Environment Engineering,Shanxi University;State Environmental Protection Key Laboratory on Efficient Resource-utilization Techniques of Coal Waste;

    In order to achieve the rapid measurement of specific surface area and pore structure of coal-based activated carbon,the relationship between iodine value and specific surface area,pore structure of activated carbon were analyzed.The correlation between BET and iodine value were determined.The results show that there is a good linear relationship between iodine adsorption and specific surface area when the iodine adsorption value ranges from 50 to 800 mg/g.It is a fast and efficient method to estimate specific surface area and micropore structure by using iodine adsorption value,and it can be used to predict the BET.However,the improper selection of relative adsorption pressure(P/P0) and C constant will lead to inaccurate measurement of specific surface area.The iodine adsorption value mainly characterizes the development pores of 0.8-1.2 nm of activated carbon.The iodine molecules are monolayer adsorbed in microporous,which is in line with a surface-covered model consisting of a hexagonal lattice of dense packing. Therefore,iodine adsorption value can be used to rapidly analyze the specific surface area and pore structure of coal-based activated carbon.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 243K]

  • Development and activity evaluation of complex catalyst for coal tar hydrogenation

    HU Fating;Coal Chemistry Branch of China Coal Research Institute;State Key Laboratory of Coal Mining and Clean Utilization;

    Because of the shortage of petroleum in China,it has important significance to produce fuel oil and fine chemicals from the hydrogenation of considerable amount of coal tar.Combined with the advantages of noble metal and iron catalyst,a composite catalyst for heavy oil hydrogenation by multistage grinding and temperature programmed calcination was developed.The hydrogenation activity of composite catalyst was evaluated and compared with coal tar heavy oil.The experimental results show that the activity of composite catalyst is high,and the pressure has little effect on the hydrogenation activity.The reaction temperature and residence time have obvious effect on the hydrogenation activity.The more suitable reaction conditions are 450 ℃,17 MPa and 60 min.The hydrogenation activity of composite catalyst is higher than that of noble metal catalyst and iron catalyst.After hydrocracking,the density and viscosity of coal tar heavy oil decrease obviously,and the average molecular weight decreases by 15.8%,and the H/C atom ratio is improved apparently.The content of N and S atoms are greatly reduced,and the asphaltene content decreases from 36.56% to 19.31%.The preparation of complex catalyst is environmentally friendly with the advantages of high activity of noble metal catalyst and low cost of iron catalyst.Therefore,the applicability of composite catalyst should be studied by using other heavy oil as raw material.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 158K]

  • Numerical simulation of effect of water vapor and oxygen concentration on pulverized coal MILD combustion

    ZHU Xinyang;ZHANG Liqi;LUO Junwei;WANG Wenzhe;YANG Wenhai;Wuhan Wuguo Energy Engineering Co.,Ltd.;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

    Due to the fact that water vapor has specific gasification reaction with coke and can reduce the burning rate,air blending water vapor is expected to be a mean of promoting the coal MILD combustion.Based on the pilot-scale furnace of IFRF,the effects of different O_2 and H_2O concentrations on the air-MILD combustion of pulverized coal was investigated by numerical simulation.The results show that increasing the H_2O concentration at different oxygen concentration will make the furnace temperature distribution more uniform,and the proportion of gasification reaction with coke is improved.It is beneficial to the realization of MILD and make thermal-NO decreased from 798×10-6 to 121×10-6 at most.With the increase of O_2 concentration,the peak temperature and whole temperature of the furnace increase obviously.The higher furnace temperature can promote the formation of thermal-NO and the gasification reaction,and thus inhibit the fuel-NO.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 389K]

  • Experiment study on formation law of chain hydrocarbons at coal combustion phase under the condition of lean oxygen

    LU Guobin;ZHANG Fuge;GUO Xiaoyang;School of Safety Science and Engineering,Liaoning Technical University;

    In order to investigate the formation mechanism of chain hydrocarbons during coal spontaneous combustion under the conditions of oxygen lean,the No.8 coal from Guandi Coal Mine was selected as test coal sample.The temperature programmed test of coal spontaneous combustion under the conditions of lean oxygen was designed. The variation law of chain hydrocarbons using gas chromatograph was obtained when initial oxygen volume fraction φ(O_2) was 21%,10% and 7%.In addition,the influence of the oxygen-lean degree on the generation of chain hydrocarbons gases was analyzed by the composite gas index. Test results show that under the oxygen-lean condition,the increase of oxygen-lean degree will decrease the generation amount of alkane,while its rising trend will demonstrate a " delaying" phenomenon.It seems to be unreliable to forecast coal spontaneous combustion disaster.The prediction of coal spontaneous combustion can be carried out by using the specific gases of alkene if the volume fraction of olefin reaches its maximum value when the spontaneous combustion of coal enters the stage of intense combustion.The ratio of olefin/alkane is more fluctuant,and the ratio of C_2H_6/CH_4 decreases with the increase of oxygen-lean degree,which can be used as the basis for characterization the coal spontaneous combustion when φ(O_2) is 7%.While the ratio of olefin/alkane decreases with the increase of oxygen-lean degree,therefore it can forecast coal spontaneous combustion disaster.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 365K]

  • Civil clean coal combustion and emission characteristics in the Beijing-Tianjin-Hebei region

    WANG Dongsheng;BAI Xiangfei;LIU Mingrui;DING Hua;WANG Chen;Coal Chemistry Branch of China Coal Research Institute;State Key Laboratory of Coal Mining and Clean Utilization;

    In view of the problem of difficult to ignite,easy to break fire and less resistance of fire in combustion process of civil anthracite and semi-coke,the combustion and emission characteristics of semi-coke,anthracite and mixing briquette were studied through combustion test device.Results show the ignition temperature of semi-coke and anthracite are 449 ℃ and 504 ℃,respectively.The burning weight loss and mass loss rate of semi-coke are higher than that of anthracite,illustrating that semi-coke presentes low ignition temperature and fast combustion rate compared with anthracite,and mixed briquette can take account of the combustion characteristics of semi-coke and anthracite.The mixture of semi-coke and anthracite is suggested to be the raw material for briquette.The particle concentration of three samples are lower than 30 mg/m3,content of SO_2 and NOxare lower than 40 mg/m3 and lower than 140 mg/m3,and the ringelmann blackness is grade 0.The test result is in conformity with national standards indicating semi-coke,anthracite and briquette would be the ideal civil clean fuel.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 571K]

  • Experimental study on optimized combustion regulation of 330MW circulating fluidized bed boiler

    LI Nan;ZHAO Pengbo;SHI Bin;LI Yuzhe;SHI Qirong;ZHONG Yi;GAO Hongpei;SUN Xianbin;Huaneng Clean Energy Research Institute Co.,Ltd.;State Key Laboratory of Coal Based Clean Energy;SPIC JIANGXI Electric Power Co.,Ltd.FENYI Power Plant;

    A circulating fluidized bed(CFB) boiler had the problems of lower efficiency,higher temperature of standpipes and unreasonable running parameters.Under the load of 300 MW and 250 MW,experiment was conducted to optimize the oxygen,then optimize primary air rate and bed pressure in the best oxygen range respectively. The results show that,boiler efficiency reaches 91. 36% under the load of 300 MW with the oxygen of 3. 3%,the primary air rate of 38% and the bed pressure of 8. 2 k Pa.The boiler efficiency achieves 90. 22% under the load of 250 MW with the oxygen of 4. 75%,the primary air rate of 40% and the bed pressure of 7. 7 k Pa.A lubricating air system is suggested to build for the high temperature of standpipes,and the source of coal distributing air is suggested to be removed for the shortage of secondary air.The experimental results indicate that appropriate reduction of bed pressure and primary air rate can reduce energy consumption and increase boiler efficiency.The results can be applied to the optimal operation adjustment of 300 MW grade CFB boilers.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 1654K]

  • Heterogeneous ash melting behavior of pulverized Zhundong coal

    ZHANG Heng;ZHANG Pengqi;WANG Zuwei;YANG Qiqi;WANG Yuelun;ZHANG Hong;Coal Testing Technology Center,Qinhuangdao Entry-Exit Inspection and Quarantine Bureau;School of Chemical Engineering and Technology,China University of Mining & Technology;

    To solve the slagging problem during coal combustion,Zhundong coal was separated into different density fractions by float-sink test.Chemical composition,mineral composition,coal ash fusion temperature and sintering temperature were measured to explore microscopic heterogeneous ash melting behavior and slagging mechanism.Results show that the density fractions are mainly concentrating in range of1. 40-1. 50 g/cm3.Obvious changes of SiO_2,CaO,Fe_2O_3 and Mg O are found in the ranges of 28. 82%-60. 27%,29. 91%-3. 96%,5. 85%-12. 68% and 9. 09%-1. 92%,respectively,as the density of raw coal increases from less than 1.50 g/cm3 to above 1. 60 g/cm3.The softening temperatures correspondingly decrease from 1 297 ℃ to 1 127 ℃,while the sintering temperatures raise from 551 ℃ to above 1 000℃.Mechanism analysis shows that the variation of chemical composition and minerals are the fundamental reason for heterogeneous melting behavior,while special composition of Zhundong coal leads to the different trends of melting and sintering.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 1069K]

  • Numerical simulation of SNCR reaction mechanism and de-NOx characteristics in circulating fluidized bed boiler

    LI Minglei;ZHANG Hailong;YANG Mingqiang;Suzhou TPRI Ener & Enviro Tech Co.,Ltd.;Xi'an Thermal Power Engineering Institute Co.,Ltd.;Huaneng Shanxi Low-carbon Technology Co.,Ltd.;

    In order to verify the accuracy of two-step reduced mechanism of SNCR reaction,complex mechanism and reduced mechanism were separately simulated.The results show that the NO and NH_3 concentration of two mechanisms on reactor outlet are relatively close at the temperature ranging from 920 ℃ to 1 040 ℃.The SNCR reaction in the cyclone of a CFB boiler was numerically simulated with the reduced mechanism.The results show that as the temperature increases,the denitration efficiency increases at first,reaches the maximum value at about 925 ℃,and then decreases,but the ammonia escape continues to decrease.As the amount of reducing agent increases,the maximum efficiency temperature stays around 925 ℃,and both denitration efficiency and ammonia escape increase,but the growth rate of efficiency gradually falls off while the growth rate of ammonia escape increases by degrees.The raise of the oxygen content of the flue gas can make the reaction temperature window move towards lower temperature and reduce both denitration efficiency and ammonia escape.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 2846K]

  • Multilayer flue gas recirculation techniques on NOx removal in chain-stoked boiler

    DU Shi;FAN Junjie;ZHANG Zhongxiao;GUO Xinwei;ZHANG Leyu;School of Environment and Architecture,University of Shanghai for Science and Technology;

    In order to study on the multilayer flue gas recyculation techniques on NO_x removal in chain-stoked boiler,a 70 MW chain-stroked boiler was upgraded using multilayer flue gas recirculation technology with upper,middle and lower multilevel air distribution to reduce the NO_x emission.A test research was conducted on the NO_x emission factors including the different of flue gas recirculation ration and the position of gas recirculation.The results show that by using the technique of upper,middle and lower multilevel air distribution for gas recirculation,the least amount of NO_x emission in the chain-stoked boiler is achieved,and the highest nitrogen removal rate is 20. 3% with the gas recirculation rate at 15%.Tests show that the upper,middle and lower multilevel air distribution for gas recirculation is obviously superior to air distribution at bottom air chamber.It can effectively reduce the emission of NO_x .This paper provides a reference for the popularization and application of the actual chain boiler operation using of the multilayer gas recirculation technology.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 2765K]

  • Dissolution and polymerization of Si and Al in alkaline solution by circulating fluidized bed fly ash

    ZHANG Xianglan;YANG Guoming;LYU Feiyong;TANG Xi;School of Chemical and Environmental Engineering,China University of Mining & Technology(Beijing);

    In order to increase the utilization rate of circulating fluidized bed fly ash,the effects of alkali concentration,temperature,reaction time,liquid-solid ratio on Si,Al dissolution rate were studied.Results demonstrate that alkali concentration,temperature,time,liquidsolid ratio affect the dissolution of active Si and Al in fly ash.When the alkali concentration is 9 mol/L,the reaction temperature is 90 ℃,the reaction time is 4 min and the liquid-solid ratio is 20,Si dissolution rate is 70%.When the concentration of alkali is 6 mol/L,the reaction temperature is 75 ℃,the reaction time is 16 min and the liquid-solid ratio is 20,Al dissolution rate is 82%.When the dissolution temperature reaches 90 ℃,Si and Al concentration are higher than 0.05 mol/L and 0.07 mol/L separately,Si and Al in the solution will polymerized.With the concentration of Si and Al increase,aluminosilicate colloids is formed first,then these colloids aggregates to form aluminosilicate sol,finally aluminosilicate gel is formed.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 2773K]

  • Experimental study on oil shale drying based on vibration and mixing flow technology

    WANG Xingkun;SHI Changjiang;LYU Peng;WU Peng;LIU Dahai;LIU Pan;Beijing Guodian Futong Science and Technology Development Co.,Ltd.;Nari Group Corporation(State Grid Electric Power Research Institute);

    In order to solve the problems of high energy consuming and low oil quality arising from moisture content of feeding in oil shale retorting process,the drying system baseed on vibration and mixing flow technology was proposed.By adjusting the flow ratio of gas to air in the combustion chamber,the desiccator's water removal effect on oil shale was studied under different treatment quantity and flue gas temperature.The experimental results show that the drying system based on vibration and mixing flow technology can dewater oil shale effectively,and the dehydration efficiency is more than 70%.When the inlet temperature of flue gas is 210-220 ℃,the water removal rate of oil shale is the highest,and the fitting equation between the water content of raw material and the quantity of supplementary gas is obtained by theoretical calculation and data analysis.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 934K]

  • Rapid detection of bomb calorific value for steam coal

    JIANG Hanyuan;Shangyuquan Coal Mine,Shenhua Guoneng(Shendong Power) Group Co.,Ltd.;

    In order to achieve rapid and accurate detection of coal quality indicators for steam coal preparation plant,rapid detection of ash in manual sampling of coal belt conveyor and in trains were performed in Shangyuquan Coal Mine Washing Center referred to the rapid ash detection method commonly used in coking coal preparation plants.According to the features of steam coal preparation plant,a rapid detection method for calorific value was proposed,and the application effects of the two schemes,i.e.,rapid detection of bomb calorific value for train commercial products and rapid detection of bomb calorific value by automatic sampling of corrugated coal belt machine,were analyzed.The results show that the rapid detection of ash has disadvantages,such as lagging results,large errors and poor guidance in steam coal preparation plant.After rrapid detection of bomb calorific value for train commercial products,the test period is reduced from 1 h to about 15 min,and the optimal time is significantly shortened. However,the adjustment of production parameters still lags behind,which can't reflect the real-time changes of coal quality.The average absolute error between rapid detection of bomb calorific value by automatic sampling of corrugated coal belt machine and normal detected calorific value is only-0.12 MJ/kg,and the average relative error is only-0.64%.The test period is reduced from 1 h to 15 min,and timeliness is from 3 d to 2.75 h.Taking into account the rapid detection of bomb calorific value is intended to guide the production rather than settlement,above method can meet the requirements.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 368K]

  • Analysis and demonstration of expander application in rectisol unit

    LIU Wen;Sinopec Ningbo Engineering Co.,Ltd.;

    In order to adapt to the increasing requirement for refinery and other chemical plants,and to better recycle the energy and utilize high pressure fuel gas decompression by-product from coal to syngas plant,the cost of decompression system of rectisol in a 2 000 million t/a coal to syngas plant was systematically analyzed.It was found that setting expander would be the most effective strategy for recycling energy.Study also made a comprehensive comparison on cascade,parallel or cascade-parallel setting modes by adjusting process configuration,stability and reliability,control system,investment and cost,etc.The results show that one-train one-stage setting mode is difficult to be applied for large volume,high expansion ratio case,and multi-trains one-stage setting mode usually fails because of CO2 freezing at the outlet with an excessive low temperature.As well,one-train multi-stages or multi-trains multi-stages setting mode would be pragmatic,but the ultimate selection should take the actual situations into consideration.In addition,this study also discusses the expander control systems to provide a reference for expander application of similar plants.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 1325K]

  • Analysis and measurement of slime water with difficult subsidence in coal preparation plant

    WANG Yuming;ZHANG Aiqing;Environmental Protection Agency,Datong Coal Mine Group;

    In order to deal with the difficult sedimentation slime water,high ash fine-grained slime water treatment in coal preparation plant of Datong Coal Mine Group is adopted as the object of this study. The main factors,variation of water quality and mineral composition of high-ash fine-grained slime water during coal preparation were introduced.The influence of main factors on the flocculation and sedimentation of coal slime water was studied,and the measurements to solve the difficult settling coal slime water were proposed. The results show that the water quality requirements of the slime water with difficult subsidence is improved to be closed circuit circulation by adding a mixed reaction tank,reducing the concentration of the pool to remove the load,extending the length of the thickened pool hydraulic retention time,the slime water conditioning,amphiphilic and positive organic polymer flocculant dosing and other measurements.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 203K]

  • Analysis and solution of the impact phenomenon in the middle bunker of industrial coal powder boiler

    WANG Shipu;LI Dianxin;LUO Wei;QIU Xing;YU Haipeng;China Coal Research Institute Company of Energy Conservation;

    When the industrial pulverized coal boiler pulverized coal bunker is discharged into the intermediate bin,the negative pressure fluctuation of the furnace often increases,which brings potential safety hazard.The instability of pulverized fuel supply is one of the reasons for the increase of negative pressure fluctuation in the furnace.In order to solve this problem and understand the working characteristics of the spiral conveyer feeder,the energy conservation law and the momentum theorem were analyzed in combination with the requirements of the stability and uniformity of the supply material in the industrial pulverized coal boiler system.It was considered that the main factor causing the fluctuation was the unequal impact of the free falling body movement of pulverized coal on the material surface and conduction to the bottom of the intermediate bin,which leaded to the constant change of the density of the pulverized coal pile at the bottom of the middle silo,and made the actual material amount of the downstream spiral feeder change.At last,it caused the unstable supply of the feed.In order to increase the flow distance of pulverized coal in the intermediate warehouse,the internal structure of the intermediate bin was redesigned and the design of the umbrella cap was added. The actual test proves that the transformation of the internal structure of the intermediate warehouse is effective,but in practical application,the design of the umbrella cap still has room for improvement.Finally,combined with the convenience and maneuverability of the actual operation and maintenance,a scheme was proposed to design a fixed umbrella cap and a diversion plate in the middle of the middle storehouse. It prores that internal structure of the intermediate storehouse meets the theoretical needs,and it is practical,and effectively alleviates the problem of the impact of the blanking.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 849K]

  • Experimental study on critical velocity of slurry pipeline transportation

    XU Zhenliang;CAI Ronghuan;WU Riquan;WANG Tieli;College of Mining,Liaoning Technical University;Department of Pipeline Coal Transporting,Wuhan Design & Research Institute Co.,Ltd of China Coal Technology & Engineering Group;

    In order to accurately calculate the critical velocity of slurry pipeline transportation,the influence of slurry concentration,pipeline diameter,slurry size distribution and slurry density on the critical flow velocity was analyzed according to previous experimental data,and the mechanism was elucidated.The results show that with the increase of slurry concentration and pipeline diameter,the critical velocity increases,while the critical velocity decreases gradually with the increasing of particle size and diameter ratio.On the basis of previous studies,a new model for calculating critical velocity and a new definition on critical velocity are proposed. It is fitted by dimensional analysis and verified by experiment.The maximum error between calculated value and measured value is 2. 69%,and the average error is 1. 29%.The average error of measured critical velocity and tested value from three famous scholars are 4. 18%,10. 25%,11. 45%,respectively.The average error of the new formula to verify the calculation of critical velocity is less than 12%,which meets the prediction of critical velocity.

    2018 03 v.24;No.115 [Abstract][OnlineView][HTML全文][Download 461K]
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