2018年05期目次

  • Research status and industrialization progress of extracting Al2O3 from fly ash

    LI Xiaoguang;DING Shuqiang;JOW Jinder;ZENG Yuping;WANG Ke;MA Ning;Advanced Materials Research Center,National Institute of Clean-and-Low-Carbon Energy;State Key Laboratory of High Performance Ceramics and Superfine Microstructure,Shanghai Institute of Ceramics,Chinese Academy of Sciences;

    In view of the shortage of bauxite resources in China and the increasing demand for bauxite,the extraction of Al_2O_3 from fly ash,especially from high alumina fly ash,can effectively supplement the amount of aluminum resources in China.In this paper,the characteristics,deficiency and industrial development of different processes of extracting Al_2O_3 from fly ash( acid extraction technology,alkaline extraction technology,alkaline sintering-acid dissolution combined extraction) were analyzed.The key problems to solve aluminum extraction from fly ash were discussed,and the development trend in the future was pointed out.Acidne extraction process of aluminum has advantage,such as simple process,dissolving Si,Al and other elements simultaneously,whereas there are some problems such as high requirements for equipment,large output of waste acid and low extraction rate.Alkaline extraction process of aluminum is relatively mature,but large output of calcium silicate slag,high energy consumption and high cost seriously restrict the industrialization development.High efficiency extraction of Al_2O_3 can be realized by using alkaline sintering-acid dissolution combined process,but there are also some disadvantages,such as complex process,large consumption of strong acid and strong alkali,difficult separation of Al_2O_3 with multiple ions.In the future,the existing aluminum extraction process should be optimized and improved,and the cooperative development of high value-added silicon products and extraction of trace elements and so on should be taken seriously. Low energy consumption,low cost,high efficiency and no secondary pollution are the important development direction of aluminum extraction technology from fly ash.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1790K]

  • Progress on oxygen carrier in chemical-looping combustion

    LIU Haitao;GAO Haichao;GAO Zhifang;School of Metallurgical Engineering,Anhui University of Technology;Key Laboratory of Metallurgical Emission Reduction and Comprehensive Utilization of Resources,Anhui University of Technology;

    CO_2 produced by the combustion of fossil fuels is one of the major greenhouse gases.Chemical-looping combustion process can not only separate and capture CO_2 with low energy consumption,but also is an important means for the preparation of hydrogen and other industrial synthesis gases.The oxygen carrier is the key to the entire chemical-looping combustion system.The development status of preparation,composition and doping modification of oxygen carrier were discuessed,and current problems,research difficulties and prospects of oxygen carrier were analyzed.In the traditional preparation method of oxygen carrier,the mechanical mixing and impregnation methods are simple in operation process and low in cost,but the prepared oxygen carrier sample has poor uniformity,and it is difficult to ensure the activity and stability.Chemical co-precipitation,freezing granulation method and sol-gel method can improve the uniformity of the components of the oxygen carrier to some extent,but it is not suitable for large-scale application because of unmanageable microstructure,complex operation and high preparation cost.The preparation method of the oxygen carrier should be low-cost,high-efficiency and refined control.At present,the iron-based oxygen carrier in the commonly used oxygen carrier has low activity,the nickel-based and manganese-based oxygen carrier is unfavorable to the environment,and the copper-based oxygen carrier is easy to be sintered.It can improve the characteristics to a certain extent by addition of the inert carrier and the alkali metal,but there is still a gap between low cost,high activity,environmental friendliness and long working life.Therefore,further research on the synergistic mechanism between oxygen carrier components and doping components is the key to oxygen carrier optimization.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1062K]

  • Determination of alkali metal content in high alkali coal and its application

    ZHU Chuan;Coal Chemistry Branch of China Coal Research Institute;School of Chemical and Environmental Engineering,China University of Mining and Technology( Beijing);State Key Laboratory of Coal Mining and Clean Utilization;

    According to the national standard method,the high temperature ashing method is widely used to determine the content of alkali metals in coal,but it is difficult to obtain accurate measured values due to release of partial active alkali metals during the ash process.The influencing factors of the determination of alkali metals were analyzed in term of the occurrence form of alkali metals,pretreatment temperature,heating rate,atmosphere,etc.Furthermore,the development and application status of the determination methods based on the special occurrence modes of alkali metals in high alkali coal in recent years,such as low temperature ashing method,direct dissolution method,extraction method and oxygen bomb method,etc.were also discussed. In the future,research should be focud on the repeatability and reproducibility of alkali metal determination methods in coal,establishing scientific,reliable and convenient standard methods,developing convenient,efficient and low-cost on-line alkali metal monitoring technology and realizing rapid prediction of correlation between alkali metal content in gas phase and engineering problems such as contamination and slagging.It proposes that the in-situ monitoring technology based on the concentration of alkali metals in combustion or gasification process is highly practical and may be the research direction of the quantitative determination of alkali metals in high alkali coal.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1656K]

  • Occurrence characteristics and industrial prospects of lithium and gallium in coal in Taiyuan Xishan coalfield

    LIU Hanbin;MA Zhibin;GUO Yanxia;CHENG Fangqin;Institute of Resources and Environmental Engineering,Shanxi University;Shanxi Coal Geological Bureau;

    In order to study occurrence characteristics of lithium and gallium and cut off grade in Taiyuan Xishan coalfield,the distribution characteristics and determinant of lithium and gallium in the coal-bearing strata of the Xishan coalfield were discussed.The relationship between lithium and gallium content of coal and gangue and Al_2O_3,kaolinite and granularity was analysed,and intrinsic storage capacity and industrial prospects in the coal-bearing strata of the Xishan coalfield were discussed. Research show that the lithium content in coal from Xishan coalfield is higher than the average value of lithium in coal from the country,and the content of gallium in coal is higher than the average value of Shanxi coal.The contents of lithium and gallium in coal gangue are significantly higher than those in coal seams,but they are lower than the recommended recovery index for lithium and gallium in coal.Vertically,the lithium content of coal in the Shanxi group is higher than that in the Taiyuan group,but this feature is not evident in the clips.Besides,the content of lithium and gallium shows a good positive correlation with Al_2O_3 content in coal,and mainly exsited in the coarse-grained material,while it is less in the fine-grained material.The intrinsic resources of lithium and gangue in the coal-bearing strata of the Xishan coalfield are 23 900 tons and 71 000 tons respectively.However,under current economic and technological conditions,lithium does not have industrial development value.The coal seam in the lower Shanxi Formation in the ancient Jiaojia Xingjiashe mining area and the No.8 coal field in the Malan mining area has a potential industrial value as it is close to the boundary grade between coal and medium saggers.It has significance for the development and utilization of coal and coal gangue in Xishan Coalfield.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1420K]

  • Release characteristics of alkali metal and Cl species in high alkali coal

    ZHAO Yonggang;SHI Hang;WU Yuxin;XU Huijun;LYU Junfu;BAI Yang;Shenhua Guoshen Technical Research Institute;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University;China Energy Investment Co.,Ltd.;

    The physical and chemical characteristics of coal ash are closely related to the ashing temperature.The release characteristics of alkali/alkaline earth metal( AAEM) and chlorine in high alkali coal were investigated experimentally at different ashing temperatures. The content of AAEM and Cl in different samples were analyzed and compared by X-ray fluorescence spectroscopy( XRF) and inductively coupled plasma optical emission spectroscopy( ICP-OES).It is found that ash contents and alkali metal contents in coal ash decrease with increasing the ashing temperature,while the change of alkaline earth metal is insignificant.The release of chlorine starts at temperature below 500 ℃,and completely release before 815 ℃. Na release characteristic is closely related to the content of chlorine in the coal. Low-temperature ashing is difficult to burnout the carbon in high ash coals,however,its relative error in alkali metal measurement is limited.The content of element detected by ICP-OES is lower than that of XRF,however,the alkali/alkaline earth metal content obtained by the two test methods is consistent with the change of the ashing temperature.Therefore,it is recommended to use the ICP-OES to measure AAEM content due to its higher accuracy.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1482K]

  • Experimental study on preparation of gasification coal water slurry by gap-graded process

    DU Liwei;HE Hongxing;CAI Hongtao;ZHANG Guiling;China Coal Research Institute Company of Energy Conservation;National Coal Water Mixture Engineering Technology Research Center;State Key Laboratory of Coal Mining and Clean Utilization;National Energy Technology and Equipment Laboratory of Coal Utilization and Emission Control;

    In order to improve the concentration of lignite water slurry,lignite and clean coal were used to investigate the effects of different coal blending methods on the concentration,viscosity and fluidity of lignite water slurry,and then obtained the optimal scheme.The results show that lignite features high moisture,high volatile,high reactivity,and lower calorific value and coal water slurry concentration,while the clean coal has the characteristics of low moisture,high calorific value,poor reactivity,and high coal water slurry concentration.The highest coal water slurry concentration of lignite and clean coal are 51.89% and 73.75%,respectively.When the mass ratio and thickness ratio of lignite and clean coal are 6 ∶ 4 and 7 ∶ 3,and the dosage of additive is 0.3%,the highest coal water slurry concentration is up to 61.24%with apparent viscosity of 1 298 m Pa·s,the fluidity of B and the slurry flow spread area of 192 cm~2. Further,the fluidity and stability of prepared coal water slurry show good state,which meets the design requirements.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1023K]

  • Characteristics of slags generated from multi-nozzle opposed coal-water slurry gasifier

    SONG Ruiling;LI Jing;FU Liangliang;XU Yi;LAN Tian;The Research Center for Clean Coal Technology and Engineering,Yankuang Group Co.,Ltd.;Yankuang Technology Co.,Ltd.;

    In order to realize the reduction and harmless utilization of the slags from multi-nozzle opposed coal-water slurry gasifier,the coarse slag and fine slag generated in Shaanxi Future Energy Chemical Corp of Yankuang Group were analyzed.The characteristics of particle size distribution,loss on ignition,chemical composition,microstructure,residual carbon distribution and surface morphology of gasified slag were systematically studied.As well,its comprehensive utilization approach were proposed. The results show that both coarse slag and fine slag are featured with high loss of ignition( 18.79% and 30.57%,respectively),which is mainly attributed to the residual carbon in slag.The residual carbon of fine slag is higher than that of coarse slag.Furthermore,the residual carbon increases with the increase of particle size in fine slag,while the residual carbon in coarse slag is mainly distributed in the medium diameter of 0.500-0.125 mm.SEM results show that the slag particles could be classified into three categories,i.e.,porous irregular particles,bonded spherical particles and separate large spherical particles.The clusters on the porous irregular particles are consist of carbon,while the components of the spherical particles are mainly as aluminum silicates.The pores of coarse slag and fine slag are mainly 4-10 nm mesoporous,and the pore structure and specific surface area of fine slag are better than those of coarse slag. Based on the observed slag characteristics,the slag can be used as fuel blending in CFB,adsorbent material for waste water treatment and building materials blending materials.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 5414K]

  • Effect of system peaks in liquid chromatography on hydrocarbons of coal-derived oil

    LI Junfang;Coal Chemistry Branch of China Coal Research Institute;State Key Laboratory of Coal Mining and Clean Utilization;

    To investigate and avoid the influence of liquid chromatographic system peaks on the determination of hydrocarbon group composition of coal based oil products,an effective method was developed by positive phase high performance liquid chromatography( HPLC).Taking NH_2 column as stationary and n-hexane as mobile phase,the separation process was detected by a differential refractive index detector.The response factor and retention time of each group compound was determined by standard substances,and the reliability of experimental results was analyzed.The results show that,after using single standard substance of saturated hydrocarbon,special-shaped peak is appeared due to the interference of system peak. Taking advantage of hybrid standard substance of saturated hydrocarbon can effectively avoid the abnormal peaks according to the small difference of retention time of different standard materials.Besides,considering the differences in the response factor of standard material will make the test results more accurate.For coal-derived middle distillate,the experimental accuracy rate is 94%-105%,and the relative deviation of saturated hydrocarbon and aromatic hydrocarbons is below 5% compared with the GC-MS results.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1474K]

  • Hydrogen supply and pyrolysis performances of typical heavy oils in China

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

    To make full use of heavy oil resources and obtain more light oil products,the conventional properties,hydrogen supply performance and the pyrolysis properties of several typical heavy oils were evaluated by property analysis,nuclear magnetic resonance( NMR) and thermogravimetric balance test.The results show that the density of coal-based heavy oil is higher than that of petroleum-based heavy oil.The high temperature coal tar has the highest density of 1 169 kg/m~3.The viscosity of the five heavy oils are different.Specifically,the viscosity of vacuum residue is the largest,while the high temperature coal tar has the lowest viscosity with a viscosity of 65.50 m Pa·s at 80℃.Besides,the H/C atom ratio of petroleum-based heavy oil is higher than that of coal-based heavy oil.The atmospheric residue has the highest H/C ratio of 1.71.The aromatics and colloids of these heavy oils account for the majority.The aromatic carbon ratio of high temperature coal tar is the highest( 0. 903),while atmospheric residue is the lowest( 0. 260). The optimum cracking temperature of heavy oils should be in the range of 430-470 ℃.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 2190K]

  • Numerical study on co-combustion process of biomass gas and pulverized coal in an opposed boiler

    XU Haopeng;REN Shaohui;SHAO Jing'ai;ZENG Kuo;YANG Haiping;ZHANG Shihong;CHEN Hanping;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;North China Power Engineering Co.,Ltd.of China Power Engineering Consulting Group;Shenzhen Research Institute of Huazhong University of Science and Technology;

    In order to explore the effect of co-combustion of biomass gas and pulverized coal on combustion and pollutant generation characteristics of boilers,Fluent was used to simulate co-combustion process of biomass gas and pulverized coal in a 600 MW supercritical opposed boiler.The effects of different co-combustion ratio( 0,10% and 20%) of biomass gas gasified by mixing rice husk,sawdust,wheat straw and rice straw at 450 ℃ on boilers combustion characteristics and pollutant generation characteristics were studied.The results show that increase of co-combustion ratio is beneficial to promote the combustion characteristics of the boiler when mixedly burning biomass with coal.However,the amount of flue gas generated by the boiler will increase,resulting in a decrease in the overall combustion temperature of the boiler.When the co-combustion ratio is increased by 10%,the combustion temperature will be reduced by 50 ℃.With the increase of co-combustion ratio,the content of O_2 in the boiler will decrease and the combustion will become more intense.As a result,the CO reacts rapidly and completely,resulting in an rise in the amount of CO_2,while the concentration of SO_2 and NO_x decreases.When the co-combustion ratio is 20%,the concentration of SO_2 and NOxcan be reduced by about 21% and 48%,respectively.Co-combustion results of numerical simulation is more credible,and co-combustion biomass gas can reduce pollutant emissions from boilers significantly.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 2265K]

  • Numerical simulation of deep air-staged technology in pulverized coal industrial boiler

    WNAG Pengtao;WANG Naiji;CHENG Xiaolei;WANG Yongying;LIANG Xing;China Coal Research Institute Company of Energy Conservation;State Key Laboratory of Coal Mining and Clean Utilization;National Energy Technology & Equipment Laboratory of Coal Utilization and Emission Control;

    In order to investigate the effect of air-staged low-nitrogen combustion technology on combustion process of pulverized coal industrial boilers and reduce the initial emission of NO_x,the influence rule of air classification depth on boiler combustion and initial emission of NO_x was firstly explored through the numerical simulation in a 40 t/h pulverized coal industrial boiler in China Coal Research Institute Company of Energy Conservation.The accuracy of simulation results was verified by engineering test. The simulation results show that the average temperature at outlet of burner increases from 980 K to 1 530 K with third-air ranging from 0 to 50%,and the temperature distribution is more uniform as the air classification depth deepens.Besides,the flow velocity reduces about 10 m/s,and the initial emission concentration of NO_x in boiler is reduced from the maximum of 697 mg/m~3 under unstaged conditions to 30% at 424 mg/m~3 under thirdair conditions with a reduction of approximately 39%. The engineering experiment shows that the initial emission concentration of NO_x is409 mg/m~3 when the proportion of third-air is 30%,which is less than 5% difference with the numerical simulation results.That is,the numerical simulation can predict the boiler combustion and NO_x emissions well.Air-staged low-nitrogen combustion technology can effectively reduce the initial emission concentration of NO_x in pulverized coal industrial boilers.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 3697K]

  • Effect of combustion optimization adjustment on NOx emission and boiler efficiency

    CAI Pei;GE Rongcun;GE Ming;CHEN Hui;CHEN Guoqing;WANG Xiujun;DAI Weibao;Key Laboratory for Clean and Efficient Coal-Fired Power Generation and Pollution Control,Guodian Science and Technology Research Institute;

    In order to study the effect of combustion optimization adjustment on NO_x emission and boiler efficiency,the NO_x emission concentration of tail flue in A and B sides was measured by adjusting the excess air coefficient,SOFA wind opening,secondary air distribution mode,surrounding air opening and burner swing angle.Besides,the boiler efficiency was calculated by recording the related data of DCS and collecting samples.Effect of combustion optimization adjustment on NO_x emission and boiler efficiency was researched.The results show that NO_x concentration can be reduced and higher boiler efficiency can be guaranteed by decreasing oxygen contents.The NO_x emission concentration of inverted tower is 9.1% and 7.8% lower than the normal tower and equal distribution wind,respectively.The inverted tower is the lowest and normal tower is the highest.The boiler efficiency increases with the increase of SOFA wind opening and later slightly decreases,while the concentration of NO_x increases with the increase of SOFA wind opening.With the increase of surrounding air opening,boiler efficiency firstly decreases and then increases,while the NO_x emissions increases gradually.The boiler efficiency changes about 1% with surrounding air opening increasing 7%.The boiler efficiency firstly increases and then decreases with the increase of burner swing angle.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 206K]

  • Experimental study on low-nitrogen combustion technology of circulating fluidized bed boiler

    LI Nan;ZHANG Shixin;ZHAO Pengbo;REN Weifeng;GAO Hongpei;SUN Xianbin;Huaneng Clean Energy Research Institute Co.,Ltd.;State Key Laboratory of Coal Based Clean Energy;

    In order to reduce the higher original NO_x emission in a 130 t/h circulating fluidized bed boiler( CFB) boiler,the measurement of reforming separators,installing the flue gas recirculation and moving the positions of secondary air were investigated,then combustion adjustment tests was carried out in a boiler.Results show that under the rated load and the oxygen content maintained in the range of 3. 3%-3. 8%,the original NO_x emission concentration after reformingdecreases from 300-350 mg/Nm~3 to 245 mg/Nm~3 after reforming. The consumption of denitrifying ammonia water increase when the oxygen content is or <3. 3% or >3. 8%.When the oxygen is less than 2.2%,the ammonia consumption reaches 400 kg/h.Flue-gas temperature at the outlet of central tube increases with the opening of FGR and decreases with the closing of upper secondary air,while the consumption of ammonia decreases first and then increases.The results indicate that there is an optimal range of oxygen content for the NO_x emission at the outlet of reactor.Besides,both the FGR opening and the positions of secondary air have significant effects on the afterburning phenomenon.In serious case,the afterburning phenomenon will make the denitrification efficiency of SNCR lower or useless.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 2422K]

  • Correction methods of boiler characteristic parameters in high altitude area

    LIU Jiali;ZHANG Dongxu;DAN Handing;LI Yuheng;WANG Guifang;FANG Shunli;Xi'an Thermal Power Research Institute Co.,Ltd.;Qinghai Xining Power Branch of Huanghe Hydropower;

    In order to scientifically and reasonably select the furnace characteristic parameters of pulverized coal boilers in high altitude area and ensure the safe and efficient operation of boiler,the 660 MW large capacity and high parameter super supercritical boiler,which was firstly put into operation in the plateau area and obtained good combustion stability and combustion economy,was used as a sample boiler in this paper.The characteristic parameters of boiler revised according to the guide on selection of furnace characteristic parameters for large pulverized coal fired boiler at different altitudes were studied.Combined with the current design features of large pulverized coal boiler,a new revision principle was proposed.According to the new principle,the furnace cross-section heat release rate,the burn-out height of furnace and the pulverized coal residence time in the furnace are increased.The boiler is a lean blast type,which is more conducive to the combustion and burnout of the boilers in the plateau area.Further,the furnace volume is reduced,which is beneficial to reduce the boiler cost.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 2199K]

  • Development and application of new type low-NOx W-flame combustion system

    RAN Shenming;ZHANG Shanying;XIE Jia;LI Weicheng;MO Chunhong;LI Zhenshan;Clean Combustion and Flue Gas Purification Key Laboratory of Sichuan Province;Dongfang Electric group Dongfang Boiler Co.Ltd.;Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Tsinghua University;

    In order to solve the problem of high NOxemission concentration of W-flame boiler,a new type low-NOx W-flame combustion system with pulverized coal pre-separator and air-staging was proposed based on the mechanism of NOx formation and reduction of coal combustion.Effects of key factors,such as over fire air( OFA) rate,coal concentration and secondary air distribution,on aerodynamic field,coal combustion and NOxemission were studied.The new low-NOxW-flame combustion system was designed and optimized in two low-NOxretrofit projects of 300 MW subcritical boiler of thermal power plants. Test results show that boiler NOxemission is 564-680 mg/m~3 when using lean coal with dry ash-free basis volatile 13%-14%,and the unit load is between 160 MW and 320 MW,which is significantly reduced compared with the original emission about 1 200 mg/m~3.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 356K]

  • Theoretically study of MTO conversion on Fe,Co and Ni modified SAPO-34 zeolite

    LI Duichun;XING Bin;LIU Hongyan;LIU Ping;WANG Baojun;LI Ruifeng;College of Chemistry and Chemical Engineering,Taiyuan University of Technology;College of Chemistry and Chemical Engineering,Shanxi Datong University;Institute of Coal Chemistry,Chinese Academy of Science;Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province,Taiyuan University of Technology;Research Center of Energy Chemical & Catalytic Technology,Taiyuan University of Technology;

    In order to clarify the effect of molecular sieve on the catalytic activity and product selectivity of MTO reaction,density functional theory including dispersion correction( GGA-PBE-D2) has been employed to study the effect of acidic strength on the activity and selectivity of methanol-to-olefins( MTO) conversion over Fe,Co and Ni modified SAPO-34 zeolites.The relationship between acidic strength and catalytic activity of different Me APO-34 zeolites was discussed.The deprotonation energy was calculated to measure the acidic strength of different Me APO-34 zeolites,and the energy barrier and reaction heat of different MTO reaction steps over Me APO-34 zeolites were calculated to compare the activity and selectivity. Results show that the acidic strength order is Fe APO-34 > Co APO-34 > SAPO-34>Ni APO-34.The catalytic activity of ethylene formation is in order of Fe APO-34≈Ni APO-34>Co APO-34,and the catalytic activity order of propene formation is Fe APO-34≈Co APO-34>Ni APO-34.The introduced of Ni atoms into the SAPO-34 zeolite framework can enhance the selectivity towards ethylene compared with that of Fe and Co atoms,however,the introduced of Fe and Co atoms into the SAPO-34 zeolite framework has higher selectivity towards propene than that of Ni atom.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 5569K]

  • Preparation of cordierite-mullite composite from high-alumina coal fly ash

    HU Pengpeng;ZHANG Jianbo;LI Shaopeng;LI Zhanbing;LI Huiquan;Key Laboratory of Green Process and Engineering,Institute of Process Engineering,Chinese Academy of Sciences;National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology;University of Chinese Academy of Sciences;

    In order to realize the high value utilization of high-aluminum coal fly ash( HAFA),HAFA was treated with acid solution and alkaline solution in sequence,subsequently the pretreated HAFA mixed with talcum power and then calcined to prepare the cordierite-mullite composites.The effects of raw materials ratio and calcination conditions on the properties of calcination products were studied.It is found that the cordierite-mullite composite with bulk density of 1.96 g/cm~3,apparent porosity of 30.47% and bending strengths of 66.44 MPa could be successfully prepared when the raw materials' theoretical mass ratio of cordierite to mullite is 50 ∶ 50,the calcination time is 2 h and the calcination temperature is 1 370 ℃.The properties of the product meet the requirements of the standard of cordierite-mullite kiln furniture( YB/T 4549—2016),which provides a new approach to transfer HAFA into high-value products.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 2393K]

  • Preparation condition and Cu2+ adsorption properties of fly ash based geopolymer

    WANG Yingming;JIANG Liang;DONG Yanbo;ZHANG Wenguang;WANG Zining;YANG Guoming;ZHANG Xianglan;School of Chemical & Environmental Engineering,China University of Mining & Technology( Beijing);

    Pore structure and adsorption properties of geopolymers were influenced by their preparation conditions.In this paper,fly ash was used as raw material to prepare geopolymers with sodium silicate as alkali-activator.Geological polymers were prepared by different sodium silicate modulus,liquid-solid ratio,curing temperature and curing time.Then the effect of adsorbent dosage,adsorption time,initial ion concentration and p H of the solution on adsorption experiments of copper ions were studied. The pore structure of fly ash-based geopolymers and the adsorption effect of copper ions were studied by nitrogen adsorption and spectrophotometry.The results show that the pore sizes of geopolymers mainly distribute in the range of 1-3 nm and 70-110 nm.When liquid-solid ratio is 0.9,the curing temperature is 80 ℃ and the curing time is 3 days and the sodium silicate modulus is 1.4,the prepared geological polymer had the largest specific surface area and the adsorption capacity of Cu~(2+)reaches 46.3 mg/g.When the ratio of liquid to solid is 1.1,the pore content of 1. 5-6. 0 nm in the geopolymer is the highest,and the absorption capacity of Cu~(2+) is 43.1 mg/g.And the curing temperature has little effect on the adsorption effect.With the increase of curing time,the adsorption of Cu~(2+) increases.The adsorption quantity of Cu~(2+) is related to the specific surface area of geopolymer.The larger the specific surface area,the greater the adsorption capacity is. In the case of p H of the copper ion solution is less than 4,the adsorption quantity of copper ions by per gram geopolymer decreased with the decrease of p H; and the adsorption isotherm was in accordance with the Freundlich adsorption equation.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 255K]

  • Experimental study on desulfurization with complex mineralized sulfur-fixed agent in CFB boiler

    CHEN Guoyan;LI Xiaoliang;DENG Haoxin;ZHANG Anchao;ZHANG Baosen;School of Mechanical and Power Engineering,Henan Polytechnic University;

    In order to increase the efficiency of desulfurization in the furnace,reduce the SO_2 emission and comprehensively utilize the ash discharged from power plant,a complex mineralized sulfur-fixed agent with addition of Al_2O_3,CaF_2,Fe_2O_3 and other catalysts to the original limestone was developed and was tested on a 465 t/h CFB boiler.Three kinds of experimental schemes,i.e.,without desulfurizer,limestone desulfurization agent and complex mineralized sulfur-fixed agent,were carried out to compare their desulfurization effects.The results show that the addition of limestone and complex mineralized sulfur-fixed agent can reduce the concentration of SO_2 in the flue gas during JY coal combustion.When the Ca/S ratio is greater than 2.5,the addition of composite mineralized desulfurizer in furnace can achieve ultra-low emission requirements,while adding limestone is failed to achieve ultra-low emission standard.When the amount of complex mineralized sulfur-fixed agent is 5%,the desulfurization efficiency is over 95%,while the coal consumption of the boiler will be reduced by about 5%.The ash residue could be modified to produce hydraulic binders.Therefore,the complex mineralized sulfur-fixed agent can meet the desulfurization requirements of the power plant. The generated ash can be used by the cement plant to produce qualified special cement,which can be achieve the purpose of comprehensive utilization of resources.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1383K]

  • Experimental study on synergistic treatment of multi-pollutants from coal-fired flue gas

    LOU Tong;FANG Xiaodong;LU Mingzhi;XU Renfa;State Environmental Protection Engineering and Technology Center for Power Industrial Dust Control,Fujian Longking Co.Ltd.;Anhui Huainan Pingwei Power Generation Co.,Ltd.;

    In order to reach deep removal of flue gas pollutants,a multi-function gas pollution control system was installed at the inlet of dust collector of a 1 000 MW scale power plant coal fired boiler.The influence of multi-function gas pollution control system on adsorption and transformation properties of the pollutional dust,SO_3 and Hg in flue gas were studied.The results show that the device can effectively solve the emission problems which can not be solved by conventional technologies,such as PM_(2.5),SO_3 and Hg.The removal efficiencies of dust,PM_(10),PM_(2.5) and PM_1 are remarkably under the experimental conditions,and their removal efficiencies are higher than 99. 3%( < 5 mg/m~3,dry normal).When calcium hydroxide is chosen as the adsorbent with a Ca/S ratio of 1,the removal efficiency of SO_3 is 88. 78%( 0. 77 mg/m~3,dry normal),and the removal efficiencies of total Hg and gaseous Hg are 94. 272% and 75. 883%,respectively.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1865K]

  • High-efficiency demister to realize ultra-low emission of particulate matters in coal-fired power plant

    LI Runping;WANG Fengyang;YANG Zhiyong;LYU Haisheng;JIANG Jianzhong;XIAO Ping;China Huadian Coal Industry Group Co.,Ltd.;China Huaneng Clean Energy Research Institute;Coal Gangue Thermal Power Plant,Inner Mongolia Mengtai Coal Industry Co.,Ltd.;

    In order to assess the effects of High-efficiency demister to realize ultra-low emission of particulate matters in coal-fired power plant,the particle emission concentration and particle size distribution of a 200 MW coal-fired power plant with and without installing high-efficiency demister were tested in this study.The test results show that the ultra-low emission standards cannot be achieved steadily without the installation of high-efficient demister. Under the load of 120 MW and 200 MW,the average concentration of particulate matter emission are 12 mg/m~3 and 18 mg/m~3,respectively.The higher the load of the boiler,the higher emission concentration of particulate matter is.Meanwhile,the smaller the particle size,the higher the concentration of the particle number concentration emitted.However,after the installation of the high-efficiency demister,the ultra-low emission standard can be achieved under three different loads. Specifically,the average emission concentration of 150,180 and 200 MW are 3.25,2.24 and 1.82 mg/m~3,respectively.And the removal efficiency of PM_(10) by high-efficiency demister can reach 90%.Particle size analysis results show that the removal efficiency of PM_(0.1) can also reach 90%.The high-efficiency demister can be used as a substitute for the wet electrostatic precipitator,which plays a key role in the ultra-low emission transformation of coal-fired power plants.

    2018 05 v.24;No.117 [Abstract][OnlineView][HTML全文][Download 1581K]
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