Life cycle inventory analysis of CO_2 and SO_2 emission of imperial smelting process for Pb-Zn smelter

1　INTRODUCTIONImperialSmeltingProcess (ISP) ,isaprocessavailableforproductionofzincandlead .Atpresent,about 13operatingISPsmeltersproduceabout 13%ofglobalzincandlead[1] .ButISPisasignificantcontributortoindustrialgreenhouseandacidityemis sionsduetoitshighenergyconsumption .Althoughcellemissionshavebeenreducedconsiderablyinre centyears ,thegrowingglobalconcernonenviron mentalissuesisimposingpressureontherelatedcom paniestoreducetheiremissions .Becauseofthelargenumberoffeedstreams ,by…     

Using hybrid modeling for life cycle assessment of motor bike and electric bike

Life-cycle assessment (LCA) is environmental evaluation of products, materials, and processes over their life cycle. Truncation uncertainty and corresponding uncertainty are main problems occurred in process life cycle assessment (PLCA) modeling and economic input-output life cycle assessment (EIOLCA) modeling. Through combination of these two modelings in different life cycle stage and use of an uncertainty reduction strategy, a hybrid life cycle assessment modeling method was proposed in this study. Case studies were presented on gasoline-powered motorbikes (M-bike) and electricity-powered electric bike (E-bike). Web-based software was developed to analyze process environmental impacts. Results show that the largest part of life cycle energy (LCE) is consumed at use stage. Less energy is consumed in life cycle of E-bike than that of M-bike. GWP (Global Warming Potential), CO (Carbon Monoxide), PM10 (particulate matter) emission of M-bike are higher than that of E-bike, especially at use stage, AP (acidification Potential) emission of E-bike is higher than that of M-bike. Comprehensively, E-bike is energy efficient and less emitting, and better choice for urban private transportation. Foundation item: Project (G-0205-06347) supported by David and Lucile Packard Foundation in Partnership with the US Energy Foundation; Project (ICA4-2002-10023) supported by European Union     

中国不同水果生产系统温室气体排放及减排措施

水果生产系统既是温室气体(GHG)排放源,又可通过土壤固碳起到减排增汇作用.计算中国不同水果生产系统传统与优化管理措施的净GHG平衡和单位产品温室气体强度(GHGI),识别不同水果生产的主要GHG排放途径及其优化碳减排潜力,可为水果生产绿色低碳管理方案的制定提供科学对策.本文对307项常规果园管理措施和333项优化果园管理措施下的肥料投入、产量、净GHG平衡和GHGI结果进行了Meta分析,并将其按播种面积大小分为柑橘、苹果、梨、葡萄、香蕉和其他水果共6类.结果表明:采取氮肥减量、增施有机肥、灌溉减量、控制灌水周期以及水肥耦合等优化管理措施的水果生产系统,在产量及GHG减排上都具优势.传统和优化管理措施下不同水果生产系统净GHG平衡排序均为香蕉＞梨＞苹果＞葡萄＞其他＞柑橘,但优化措施净GHG平衡大幅降低53.2%~75.8%.不同水果生产系统GHGI也从传统措施下2.82±0.20(柑橘)~4.32±0.27(葡萄) kg (CO₂-eq)·kg^-1降至优化措施下0.64±0.19(柑橘)~1.40±0.13(香蕉) kg (CO₂-eq)·kg^-1.水果生产系统GHG排放的主要来源是投入氮肥在其生产和运输过程排放的CO₂-eq及氮肥诱导的N₂O排放和灌溉机械能耗CO₂排放.通过秸秆还田、地面覆盖及免耕等优化措施增加土壤有机碳可以抵消我国不同水果生产系统38.4%~66.9%的GHG排放.因此,我国水果生产系统具有较大的碳减排潜力,在未来水果消费需求大增的情况下,通过优化果园管理措施可以减缓水果生产引起的GHG排放,助力碳达峰和碳中和.     

江苏省主要农作物碳足迹动态及其构成研究

江苏作为农业大省和粮食主产区,全面核算其主要农作物生产碳足迹时序动态变化与构成,可为江苏省主要作物生产体系全过程环境管理及农业绿色发展提供决策依据.本文采用生命周期评价法(LCA)核算江苏省1990—2019年水稻、小麦、玉米、大豆和油菜5种作物生产过程各环节碳排放强度,研究分析不同作物生产碳足迹时序动态变化、构成及影...     

Using hybrid modeling for life cycle assessment of motor bike and electric bike

Life-cycle assessment (LCA) is environmental evaluation of products, materials, and processes over their life cycle. Truncation uncertainty and corresponding uncertainty are main problems occurred in process life cycle assessment (PLCA) modeling and economic input-output life cycle assessment (EIOLCA) modeling. Through combination of these two modelings in different life cycle stage and use of an uncertainty reduction strategy, a hybrid life cycle assessment modeling method was proposed in this study. Case studies were presented on gasoline-powered motorbikes (M-bike) and electricity-powered electric bike (E-bike). Web-based software was developed to analyze process environmental impacts. Results show that the largest part of life cycle energy (LCE) is consumed at use stage. Less energy is consumed in life cycle of E-bike than that of M-bike. GWP (Global Warming Potential), CO (Carbon Monoxide), PM10 (particulate matter) emission of M-bike are higher than that of E-bike, especially at use stage, AP (acidification Potential) emission of E-bike is higher than that of M-bike. Comprehensively, E-bike is energy efficient and less emitting, and better choice for urban private transportation.     

基于空气质量模拟的江苏省大气污染物排放清单比较研究

大气污染物排放清单是空气质量模拟和空气污染治理的重要依据.本研究比较分析了两套覆盖江苏省的2017年大气污染物排放清单，即分别由上海市环境科学研究院、江苏省环境科学研究院编制的"长三角清单"和"江苏省清单"，并结合区域空气质量模型CMAQ评估不同清单对长三角地区2017年1、4、7、10月的空气质量模拟的影响.清单比较结果表明，除二氧化硫（SO₂）以外，江苏省清单估算的各污染物排放量较长三角清单低.通过与观测数据比较，发现两套清单对SO₂、氮氧化物（NO_x）、臭氧（O₃）和细颗粒物（PM_2.5）的模型模拟性能均较好.江苏省清单与长三角清单两者的模拟结果空间分布接近，其中江苏省清单模拟的PM_2.5和O₃在长三角多数地区略低于长三角清单的模拟结果（1月O₃除外）.江苏省清单与长三角清单均能够用于空气质量模式模拟，可为江苏地区的细颗粒物和光化学烟雾污染的控制策略制定提供参考.     

Influence of dioxin reduction on chemical composition of sintering exhaust gas with adding urea

With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% (mass fraction) urea, the emission concentrations of dioxin are 0.287, 0.258 and 0.217 ng-TEQ/m³, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m³ free of urea. With an increase of the urea content, the concentration of SO₂ emission reduces sharply. (NH₄)₂SO₄, formed by the reaction of SO₂ and NH₃, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO _x emission presents an increasing trend because the reaction of NH₃ and O₂ at high temperature produces NO _x . Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.     

双碳目标下中国农业系统N2O排放及主粮低碳化生产研究

农业作为N₂O重要的排放源,厘清农业系统N₂O排放对"双碳"目标实现具有重要意义.本文基于2000—2019年中国种植业、养殖业数据,估算了农业系统N₂O排放量,并利用泰尔指数(Theil index)探求了中国大陆4大板块和8大经济区之间的差异性,对主粮低碳化生产提出对策建议.研究结果显示:1)中国农业系统N₂O排放呈现先增加后减少趋势,其中2000—2015年是上升阶段,从69.98万t增加到86.01万t,2016—2019年为下降阶段,2019年农业系统N₂O排放量为76.43万t.2)分省农业系统N₂O排放量差异显著,2019年农业系统N₂O排放量最少的是北京(0.056万t),最多的是河南(5.69万t);集中趋势更为凸显,广西、河南、江苏等排放量较多.3)省域之间、区域之间农业系统N₂O排放量差异呈现多样性变化,如省域差异前期先扩大后缩小,2009年以来表现平稳,8大区域中北部沿海、东部沿海、大西北区域泰尔指数呈现下降趋势,其他区域皆呈上升趋势.为实现N₂O减排,需要针对不同板块和经济区针对性开展主粮低碳化生产,需要重点针对中部板块、西部板块以及东北区域和大西南区域针对性开展低碳化生产.     

Manufacturing microporous foam zinc materials with high porosity by electrodeposition

In order to get foam zinc materials of porous metal electrode, a novel method for preparing foam zinc was proposed, in which the polyurethane foam with diameter of 0.3 mm as substrate was processed by degreasing, roughening, activating, electroless plating and electrodeposition. The main factors affecting the process, such as ZnSO₄ content, temperature, pH value, current density, and electrodes distance, were investigated comprehensively. The optimal process conditions are 250 g/L ZnSO₄, 20 g/L Al₂(SO₄)₃, 40 g/L KAl(SO₄)₂, 30 g/L Na₂SO₄, pH=3.5, 4.0 cm of electrodes distance and 0.04 A/cm² current density at 30 °C. The result shows that adding ultrasonic on the process can elevate the deepening plating ability and current efficiency. Foam zinc material with a high porosity of 92.2% and a three-dimensional network structure can be fabricated by electrodeposition.     

Temperature dependence on reaction of CaCO3 and SO2 in O2/CO2 coal combustion

The temperature dependence on the reaction of desulfurization reagent CaCO₃ and SO₂ in O₂/CO₂ coal combustion was investigated by thermogravimetric analysis, X-ray diffraction measurement and pore structure analysis. The results show that the conversion of the reaction of CaCO₃ and SO₂ in air is higher at 500–1 100 °C and lower at 1 200 °C compared with that in O₂/CO₂ atmosphere. The conversion can be increased by increasing the concentration of SO₂, which causes the inhibition of CaSO₄ decomposition and shifting of the reaction equilibrium toward the products. XRD analysis of the product shows that the reaction mechanism of CaCO₃ and SO₂ differs with temperature in O₂/CO₂ atmosphere, i.e. CaCO₃ directly reacts with SO₂ at 500 °C and CaO from CaCO₃ decomposition reacts with SO₂ at 1 000 °C. The pore analysis of the products indicates that the maximum specific surface area of the products accounts for the highest conversion at 1 100 °C in O₂/CO₂ atmosphere. The results reveal that the effect of the atmosphere on the conversion is temperature dependence.     

Study on method and mechanism for simultaneous desulfurization and denitrification of flue gas based on the TiO2 photocatalysis

Based on the TiO₂ photocatalysis mechanism, a new method of simultaneous desulfurization and denitrification from flue gas was proposed. Preparation of TiO₂ photocatalyst, design of photocatalysis reactor and influencing factors for simultaneous removal of SO₂ and NO, and removal mechanism of SO₂ and NO were studied. After the optimal values of concentration of O₂ in flue gas, the relative humidity of flue gas and the irradiation time in the photocatalysis reactor were used, the efficiencies of removal for SO₂ and NO can be achieved above 98% and about 67%, respectively. According to the results of removal products analysis, the removal mechanism of SO₂ and NO based on TiO₂ photocatlysis can be put forward, namely, SO₂ was oxidized to SO₃ partly, the bulk of NO was oxidized to NO₂, and both were removed by resorbing finally.     

Separation of cobalt and nickel by non-equilibrium solvent extraction

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中国纸产品全生命周期GHG排放分析

基于生命周期评价理论与国家温室气体清单指南中废弃物处理温室气体排放计算方法,对中国2010年和2015年纸产品生命周期不同阶段的主要温室气体排放分别进行了分析.研究的纸产品生命周期评价边界包括:林木种植管理、制浆造纸过程、运输过程、废纸回收制浆、焚烧和填埋.结果表明:中国2010年和2015年纸产品生命周期温室气体排放量分别为13.4、20.3 Mt CO2-eq,其中林木种植和管理阶段为碳汇,能存储的CO2分别为82.6和108.2 Mt CO2-eq,制浆和造纸阶段为碳源,排放的GHG2分别为52.4、77.3 Mt CO2-eq,运输阶段为8.3、10.3 Mt CO2-eq,废纸焚烧和填埋阶段为35.3、40.9 Mt CO2-eq.     

SO2-4对块体纳米晶铜阳极极化行为的影响

为了揭示SO₂^-4对块体纳米晶铜耐蚀性能的影响规律,利用电化学方法,结合X射线衍射、能谱分析、扫描电镜等表面分析技术,研究了惰性气体沉积原位温压法制备的块体纳米晶铜在不同质量分数（0.3%、1.3%、2.3%、3.3%和4.3%）Na₂SO₄溶液中的阳极极化行为.结果表明,随着SO₂^-4的增多,纳米晶铜的致钝电流密度增大,而致钝电位降低.在0.3%的Na₂SO₄溶液中加入1%的NaCl,纳米晶铜阳极极化行为发生明显变化,Cl^-在纳米晶铜表面形成难溶于水的CuCl保护钝化膜,纳米晶铜致钝电流密度降低,活化-钝化过渡区电流密度下降速率显著减小.     

Preparation and electrochemical properties of Pb-0.3wt%Ag/Pb-WC composite inert anodes

We prepared Pb-0.3wt%Ag/Pb-WC(WC stands for tungsten carbide,the same below) composite inert anodes by double-pulse electrodeposition on the surface of Pb-0.3wt%Ag substrates,and investigated the electrochemical properties of the composite inert anodes,which were obtained under different forward pulse average current densities from 2 A/dm~2 to 5 A/dm~2 and WC concentrations from 0 g/L to 40 g/L in bath.The kinetic parameters of oxygen evolution,corrosion potential and corrosion current of the composite inert anodes were obtained in a synthetic zinc electrowinning electrolyte of 50 g/L Zn~(2+) and 150 g/L H_2SO_4 at 35 ℃,by measuring the anodic polarization curves,Tafel polarization curves and cyclic voltammetry curves.The results show that Pb-0.3wt% Ag/Pb-WC composite inert anodes obtained under forward pulse average current density of 3 A/dm~2 and WC concentration of 30 g/L in an original acid plating bath,possess higher electrocatalytic activity of oxygen evolution,lower overpotential of oxygen evolution,better reversibility of electrode reaction and corrosion resistance in [ZnSO_4+H_2SO_4] solution.The overpotential of oxygen evolution of the composite inert anode is 0.926 V under 500 A/m~2 in [ZnSO_4+H_2SO_4] solution,and 245 mV lower than that of Pb-1% Ag alloy;the corrosion current of the composite inert anode is 0.95×10~(-4)A which is distinctly lower than that of Pb-1%Ag alloy,showing the excellent corrosion resistance.     

Corrosion resistance of plasma sprayed NiCrAl+(ZrO2+Y2O3) thermal barrier coating on 18-8 steel surface

The corrosion resistance of NiCrAl+(ZrO₂+Y₂O₃) thermal barrier coating, formed with the plasma spraying technique, on the 18 - 8 steel surface was investigated. The phase structure and morphology of the coating were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical corrosion behavior of the coating in 1.0 mol/L H₂SO₄ solution was studied by using electrochemical measurement methods. The results show that the gradient plasma spraying coating is composed of the NiCrAlY coating and the (ZrO₂+Y₂O₃) top coating, and the coating thickness is 360 μm. The microhardness of coating reaches 1 100 HV. The corrosion resistance of the plasma sprayed coating of the 18 - 8 steel surface is about 5 times as great as that of the original pattern. The corrosion resistance of the coating is enhanced notably. Foundation item: Project (5040202140) supported by Scientific Research Common Program of Beijing Municipal Commission of Education     

建筑物化阶段CO2排放及其不确定性分析

CO₂是导致气候变暖的主要物质之一,而建筑行业的碳排放量占世界碳排放总量的25%左右。在建筑生命周期内,年均CO₂排放最多的阶段为物化阶段,对建筑物化阶段的碳排放进行量化具有重要的研究意义。考虑排放清单等数据受人为因素及技术水平的限制,会出现一定的变异性,研究采用不确定性分析方法。将建筑按分部分项工程进行分解,结合具体的单元工序对物化阶段的CO₂排放进行量化建模,进而给出减排中最需关注的单元工序。通过案例分析发现,建筑物化阶段的碳减排重点是材料生产,其CO₂排放量占比达到93%;其次,在不同工序中,减排重点为土建工程,其碳排放占总体的85%;在碳排放量化过程中,对数据和情景两类不确定度进行计算。根据数据不确定度的结果可知,物化阶段CO₂排放总量的变异系数为0.3%,结果数据可信度较高。根据情景不确定度的结果可知,运输阶段改变运距及柴油类型可减排39%,施工阶段改变用电类型可减排27%。     

Proton conducting composite membranes from sulfonated polyether ether ketone and SiO2

Proton conducting composite membranes from sulfonated polyether ether ketone and SiO₂ for direct methanol fuel cell (DMFC) application were prepared with sulfonated polyether ether ketone(SPEEK) and tetracethoxy silane(TEOS) by sol-gel method. The covalent crosslinking structure was formed between —SO₃H of SPEEK via SiO₂. The SEM images show that the interfacial compatibility of SPEEK and SiO₂ is improved obviously and SiO₂ disperses uniformly in the polymer matrix and the particle diameter of SiO₂ does not exceed 40 nm. The proton conductivity of composite membranes decreases slightly compared with the SPEEK membrane while the methanol permeability and swelling of composite membrane are improved remarkablely owing to covalent cross-linking between —SO₃H and SiO₂.     

Selective leaching of vanadium from V-Ti magnetite concentrates by pellet calcification roasting-H_2SO_4 leaching process

A novel method of pellet calcification roasting-H_2 SO_4 leaching was proposed to efficiently separate and extract vanadium(V) from vanadium-titanium(V-Ti) magnetite concentrates.The leaching rate of V is as high as 88.98%,while the leaching rate of impurity iron is only 1.79%.Moreover,the leached pellets can be used as raw materials for blast furnace ironmaking after secondary roasting.X-ray photoelectron spectroscopy(XPS) and scanning electron microscopy with energy dispersive X-ray spectrometry(SEMEDS) analyses showed that V~(3+) was oxidized to V~(5+) after roasting at 1200℃,and V~(5+) was then leached by H_2 SO_4.X-ray diffraction(XRD) analyses and single factor experiment revealed a minimal amount of dissolved Fe_2 O_3 during H_2 SO_4 leaching.Therefore,a high separation degree of V and iron(Fe) from V-Ti magnetite concentrate was achieved through H_2 SO_4 leaching.Compared with the traditional roastingleaching process,this process can achieve a high selectivity of V and Fe,and has excellent prospects for industrial production.     

BaZr0.9Y0.1O2.95/Na2SO4 composite with enhanced protonic conductivity

Heterogeneous composite BaZr_0.1Y_0.9O_2.95/Na₂SO₄ was designed and fabricated with Y-doped BaZrO₃ as matrix and Na₂SO₄ as dispersant by conventional powder processing to improve the total conductivity of barium zirconate. The electrical conduction of the composite was studied by electrical and electrochemical methods. Microstructure of the heterogeneous composite was examined by SEM. The experimewtal results show that the protonic conductivity of Y-doped BaZrO₃ is greatly improved upon incorporating Na₂SO₄ in the material. Microstructure observation indicates that a multiphase structure with Na₂SO₄ disperses at the grain boundaries of BaZr_0.1Y_0.9O_2.95. Electromotive force (EMF) measurements under fuel cell conditions reveal that the total ionic transport number of the composite is more than 0.9 at 750 °C. Funded by the National natural Science Foundation of China(No. 50872090)