Development of non-premixed porous inserted regenerative thermal oxidizer

In this study, a porous inserted regenerative thermal oxidizer （PRTO） system was developed for a 125 kW industrial copper-melting furnace, due to its advantages of low NOr emissions and high radiant efficiency. Zirconium dioxide （ZrOz） ce- ramic foams were placed into the combustion zone of a regenerative thermal oxidizer （RTO）. Different performance characteris- tics of the RTO and PRTO systems, including pressure drop, temperature distribution, emissions, and energy efficiency, were evaluated to study the effects of the porous inserts on non-premixed CH4 combustion. It was found that the PRTO system achieved a significant reduction in the NOx emission level and a fuel saving of approximately 30% compared to the RTO system. It is most suitable for a lean combustion process at an equivalence ratio 〈0.4 with NOx and CO emission levels within 0.002%~）.003% and 0.001%q3.002%, respectively.     

Chemical kinetic modeling for the effects of methyl ester moiety in biodiesel on PAHs and NO x formation

In order to investigate the effects of methyl ester moiety on polycyclic aromatic hydrocarbons (PAHs) and NO x formation in biodiesel combustion, the combined models were developed based on detailed methyl butanoate (MB) oxidation model and n-butane model. Also, PAHs detailed reaction mechanism and NO x formation mechanism were added to the detailed models to form the combined models. The combined models were used to compare the combustion of n-butane and MB in a shock tube simulation to understand the effects of methyl ester moiety. The results indicated that compared with n-butane, the methyl ester moiety in MB leads to different reaction pathways, more CO and CO 2 formation and less formation of PAHs precursors such as ethylene and acetylene. In addition, a better chemical insight into the effects of methyl ester moiety on NO x formation was given, which will help to understand the combustion process of biodiesel.     

Modeling and multi-objective optimization of a gasoline engine using neural networks and evolutionary algorithms

In this paper, a multi-objective particle swarm optimization （MOPSO） algorithm and a nondominated sorting genetic algorithm II （NSGA-II） are used to optimize the operating parameters of a 1.6 L, spark ignition （SI） gasoline engine. The aim of this optimization is to reduce engine emissions in terms of carbon monoxide （CO）, hydrocarbons （HC）, and nitrogen oxides （NOx）, which are the causes of diverse environmental problems such as air pollution and global warming. Stationary engine tests were performed for data generation, covering 60 operating conditions. Artificial neural networks （ANNs） were used to predict exhaust emissions, whose inputs were from six engine operating parameters, and the outputs were three resulting exhaust emissions. The outputs of ANNs were used to evaluate objective functions within the optimization algorithms： NSGA-II and MOPSO. Then a decision-making process was conducted, using a fuzzy method to select a Pareto solution with which the best emission reductions can be achieved. The NSGA-II algorithm achieved reductions of at least 9.84%, 82.44%, and 13.78% for CO, HC, and NOx, respectively. With a MOPSO algorithm the reached reductions were at least 13.68%, 83.80%, and 7.67% for CO, HC, and NOx, respectively.     

2000-2020年中国氮氧化物排放清单及排放趋势

研究目的：建立2000-2020年中国氮氧化物排放清单,了解中国主要行业和省份氮氧化物的排放情况,为评估氮氧化物的环境影响和制定相关减排政策提供依据。创新要点：分析了中国主要省份产业结构对氮氧化物排放量的影响;根据不同情景分析,预测2020年中国氮氧化物的排放量。研究方法：1．基于自底向上法,根据不同类型化石燃料的氮氧化物排放因子,结合化石燃料消耗量,建立中国2000-2010年氮氧化物排放清单;2．基于IPAT方程,并以中国2000--2010年的国内生产总值增长数据和氮氧化物排放量为依据,分三种情景,分析2011-2020年中国能源消耗和氮氧化物排放趋势。重要结论：2010年中国氮氧化物的排放量约是2000年的两倍：自2009年起,中国氮氧化物总排放量超过,二氧化硫总排放量;主要由于产业结构和地区生产总值的不同,中国东部和西部氮氧化物排放量有明显差异;制造业、电力行业和交通运输业是中国氮氧化物的主要排放源,其中交通运输业氮氧化物排放量呈现逐年增长趋势;预计2020年中国氮氧化物排放量为19．7Mt。     

Development of lanthanum strontium cobalt ferrite composite cathodes for intermediate- to low-temperature solid oxide fuel cells

Solid oxide fuel cells(SOFCs) offer high energy conversion,low noise,low pollutant emission,and low processing cost.Despite many advantages,SOFCs face a major challenge in competing with other types of fuel cells because of their high operating temperature.The necessity to reduce the operational temperature of SOFCs has led to the development of research into the materials and fabrication technology of fuel cells.The use of composite cathodes significantly reduces the cathode polarization resistance and expands the triple phase boundary area available for oxygen reduction.Powder preparation and composite cathode fabrication also affect the overall performance of composite cathodes and fuel cells.Among many types of cathode materials,lanthanum-based materials such as lanthanum strontium cobalt ferrite(La1-xSrxCo1-yFeyO3- have recently been discovered to offer great compatibility with ceria-based electrolytes in performing as composite cathode materials for intermediate-to low-temperature SOFCs(IT-LTSOFCs).This paper reviews various ceria-based composite cathodes for IT-LTSOFCs and focuses on the aspects of progress and challenges in materials technology.     

A method for predicting in-cylinder compound combustion emissions

This paper presents a method using a large steady-state engine operation data matrix to provide necessary information for successfully training a predictive network, while at the same time eliminating errors produced by the dispersive effects of the emissions measurement system. The steady-state training conditions of compound fuel allow for the correlation of time-averaged in-cylinder combustion variables to the engine-out NO _x and HC emissions. The error back-propagation neural network (EBP) is then capable of learning the relationships between these variables and the measured gaseous emissions, and then interpolating between steady-state points in the matrix. This method for NO _x method for NO _x and HC has been proved highly successful.     

Numerical study on viscosity reduction in mining heavy oil by circulating hot water

Viscosity reduction is an important process in mining heavy oil.To predict the temperature variation and viscosity variation of heavy oil in flow direction,computational fluid dynamics(CFD) was adopted to simulate the process of heat transfer and flow in this paper.Moreover,an objective function,namely viscosity reduction efficiency,was established to analyze the effect of viscosity reduction.The results indicate that circulating hot water can reduce viscosity significantly,and that the effect of viscosity reduction depends on the inlet temperature and inlet volumetric flow rate of hot water.There is a maximum temperature of heavy oil in flow direction.With the inlet volumetric flow rate of 2.0m3/h and the inlet temperatures of 60,℃,70,℃ and 80,℃,viscosity reduction efficiencies are 94.6%,96.7% and 97.3%,respectively.With the inlet temperature of 70,℃ and the volumetric flow rates of 1.5m3 /h,2.0 m3/h and 2.5m3/h,viscosity reduction efficiencies are 94.4%,96.7% and 97.2%,respectively.     

杭州市机动车污染物排放的减排情景研究

研究目的：预测机动车保有量;根据机动车污染特征,预测机动车污染物排放量;评估不同管理措施下机动车污染物的削减效果。创新要点：综合不同管理措施,整合评价多种管理措施并行条件下,机动车污染物排放量的削减情况。研究方法：通过长期能源替代计划（LEAP）模型对机动车保有量进行预测,相关排放因子采用校正的能源替代（AER）模型进行估算。最后设计四个情景模式,评估不同情景的减排效果,并与基础情景进行对比。重要结论：1.至2015年杭州市机动车将增长60.7%。2.淘汰超标机动车和提高机动车污染排放标准能有效控制CO和VOCs,而对NOx和PM的总量削减效果不明显。3.采用多种控制手段,如淘汰劣化超标机动车、提高机动车排放标准、提供低硫代燃油及引进能源替换型机动车将大大减少机动车污染物的排放量。     

Experimental study on the inhibition of biological reduction of Fe(III)EDTA in NO x absorption solution

Scrubbing of NO _x from the gas phase with Fe(II)EDTA has been shown to be highly effective. A new biological method can be used to convert NO to N₂ and regenerate the chelating agent Fe(II)EDTA for continuous NO absorption. The core of this biological regeneration is how to effectively simultaneous reduce Fe(III)EDTA and Fe(II)EDTA-NO, two mainly products in the ferrous chelate absorption solution. The biological reduction rate of Fe(III)EDTA plays a main role for the NO _x removal efficiency. In this paper, a bacterial strain identified asKlebsiella Trevisan sp. was used to demonstrate an inhibition of Fe(III)EDTA reduction in the presence of Fe(II)EDTA-NO. The competitive inhibition experiments indicted that Fe(II)EDTA-NO inhibited not only the growth rate of the iron-reduction bacterial strain but also the Fe(III)EDTA reduction rate. Cell growth rate and Fe(III)EDTA reduction rate decreased with increasing Fe(II)EDTA-NO concentration in the solution. Project (No. 20176052) supported by the National Natural Science Foundation of China and the Scientific Research Foundation for Returned Overseas Chinese Scholars, Ministry of Education     

Evaluation of the adhering layer ratio of iron ore granules and its influence on combustion-generated NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> emission in iron ore sintering

In iron ore sintering, the granulation process is the first and an important step. As the fine particles adhere to the coarse coke particles, the NO _x emission generated from coke combustion may be expected to be influenced by that adhering layer. In this study, the granule size distributions and adhering ratios were evaluated by a granulation model. Granulation experiments were also carried out to obtain the granule size distribution and adhering ratio. The influence of the adhering layer on NO _x emissions from the combustion of S type granules was studied by tube furnace experiments. Conclusions include: (1) The adhering ratio predicted from the granulation model can be used as a qualitative index for the evaluation of NO _x emission from coke combustion. (2) The influence of the adhering layer on NO _x emissions was enhanced with increasing adhering layer thickness of S type granules, and the NO _x reduction was enhanced at higher temperatures (around 1373 K), but weakened at lower temperatures (around 1173 K).     

Study on NO2 absorption by ascorbic acid and various chemicals

INTRODUCTION Nitrogen oxide (NOx) is one of the main air pol- lutants found in the flue gases from chemical and power plants belching acid rain and photochemical smog. Over 90 percent of all man-made nitrogen ox- ides that enter our atmosphere are produced by the combustion of various fuels. Compared with the ad- vanced stage of SO2 gas removal technologies devel- opment, the removal of NOx gases is still in the initial stages of development as roughly 90 to 95 percent of NOx emitted i…     

Development of a NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> emission model with seven optimized input parameters for a coal-fired boiler

Optimizing the operation of coal-fired power plants to reduce nitrogen oxide (NO _x ) emissions requires accurate modeling of the NO _x emission process. The careful selection of input parameters not only forms the basis of accurate modeling, but can also be used to reduce the complexity of the model. The present study employs the least squares support vector machine-supervised learning method to model NO _x emissions based on historical real time data obtained from a 1000-MW once-through boiler. The initial input parameters are determined by expert knowledge and operational experience, while the final input parameters are obtained by sensitivity analysis, where the variation in model accuracy for a given set of data is analyzed as one or several input parameters are successively omitted from the calculations, while retaining all other parameters. Here, model accuracy is evaluated according to the mean relative error (MRE). This process reduces the parameters required for NO _x emission modeling from an initial number of 33 to 7, while the corresponding MRE is reduced from 3.09% to 2.23%. Moreover, a correlation of 0.9566 between predicted and measured values was obtained by applying the model with just these seven input parameters to a validation dataset. As such, the proposed method for selecting input parameters serves as a reference for related studies.     

腐殖酸和牛血清蛋白对氧化物纳米颗粒团聚和沉降行为的影响

研究目的：比较牛血清蛋白和腐殖酸对Al2O3、SiO2和TiO2三种纳米颗粒团聚与沉降行为的影响,并讨论其影响机制。创新要点：纳米颗粒团聚物直径的增大能引起其沉降速度的加快,但小的水动力学直径并不一定导致低的沉降速度,说明团聚直径不是决定纳米颗粒沉降的唯一因素。研究方法：通过透射电镜观察纳米颗粒团聚物的形态;采用动态光散射技术研究纳米颗粒的团聚动力学;最后通过测量悬浊液的光学吸收来研究纳米颗粒的沉降动力学。重要结论：牛血清蛋白处理降低了三种纳米颗粒在NaCl和CaCl2中的水动力学直径,原因是牛血清蛋白的球状结构能够引起颗粒间的空间位阻斥力。腐殖酸处理导致纳米颗粒的水动力学直径在NaCl中最小,而在CaCl2中最大（图4）,原因是腐殖酸能通过钙的配位作用彼此连接,从而促进了纳米颗粒的团聚。牛血清蛋白减缓了纳米颗粒的沉降;然而腐殖酸在CaCl2中明显加大了纳米颗粒的沉降速度（图5）,与其水动力学直径的增大一致。腐殖酸处理的纳米颗粒在NaCl中水动力学直径最小,但沉降速度却不是最低。     

Experiment and mechanism investigation on advanced reburning for NOx reduction： influence of CO and temperature

Pulverized coal reburning, ammonia injection and advanced reburning in a pilot scale drop tube furnace were investigated. Premix of petroleum gas, air and NH3 were burned in a porous gas burner to generate the needed flue gas. Four kinds of pulverized coal were fed as reburning fuel at constant rate of 1g/min. The coal reburning process parameters including 15%～25% reburn heat input, temperature range from 1100 ℃ to 1400 ℃ and also the carbon in fly ash, coal fineness, reburn zone stoichiometric ratio, etc. were investigated. On the condition of 25% reburn heat input, maximum of 47% NO reduction with Yanzhou coal was obtained by pure coal reburning. Optimal temperature for reburning is about 1300 ℃ and fuel-rich stoichiometric ratio is essential; coal fineness can slightly enhance the reburning ability. The temperature window for ammonia injection is about 700 ℃～1100 ℃. CO can improve the NH3 ability at lower temperature. During advanced reburning, 72.9% NO reduction was measured. To achieve more than 70% NO reduction, Selective Non-catalytic NOx Reduction (SNCR) should need NH3/NO stoichiometric ratio larger than 5, while advanced reburning only uses common dose of ammonia as in conventional SNCR technology. Mechanism study shows the oxidization of CO can improve the decomposition of H2O, which will rich the radical pools igniting the whole reactions at lower temperatures.     

Impact of diesel emission fluid soaking on the performance of Cu-zeolite catalysts for diesel NH<Subscript>3</Subscript>-SCR systems

Diesel emission fluid (DEF) soaking and urea deposits on selective catalytic reduction (SCR) catalysts are critical issues for real diesel engine NH₃-SCR systems. To investigate the impact of DEF soaking and urea deposits on SCR catalyst performance, fresh Cu-zeolite catalyst samples were drilled from a full-size SCR catalyst. Those samples were impregnated with DEF solutions and subsequently hydrothermally treated to simulate DEF soaking and urea deposits on real SCR catalysts during diesel engine operations. Their SCR performance was then evaluated in a flow reactor with a four-step test protocol. Test results show that the DEF soaking leached some Cu from the SCR catalysts and slightly reduced their Cu loadings. The loss of Cu and associated metal sites on the catalysts weakened their catalytic oxidation abilities and caused lower NO/NH₃ oxidation and lower high-temperature N₂O selectivity. Lower Cu loading also made the catalysts less active to the decomposition of surface ammonium nitrates and decreased low-temperature N₂O selectivity. Cu loss during DEF impregnation released more acid sites on the surface of the catalysts and increased their acidities, and more NH₃ was able to be adsorbed and involved in SCR reactions at medium and high temperatures. Due to lower NH₃ oxidation and higher NH₃ storage, the DEF-impregnated SCR catalyst samples showed higher NO _x conversion above 400 °C compared with the non-soaked one. The negative impact of urea deposits during DEF impregnation was not clearly observed, because the high-temperature hydrothermal treatment helped to remove the urea deposits.     

Influence of annealing conditions on the properties of Cu(In,Ga)Se<Subscript>2</Subscript> thin films fabricated by electrodeposition

Cu(In,Ga)Se₂ (CIGS) precursor films were deposited on Mo/glass by electrodeposition, and then annealed in Se vapor. The annealing temperature ranged from 450 °C to 580 °C, and two heating rates were selected. The results showed that the crystalline quality of the CIGS films and formation of the Cu-Se compound could be strongly influenced by the selenization temperature and heating rate. Raman spectroscopy and X-ray diffraction (XRD) analysis showed that when the selenization temperature was increased from 450 °C to 550 °C, the amount of binary CuSe phase decreased and the amount of Cu2Se increased. After annealing at 580 °C, a minimum amount of Cu_2?xSe compounds was obtained and the degree of CIGS film crystallinity was higher than in other samples. The relationship between the properties of the film and the heating rate was studied. XRD and Raman spectra showed a decrease in the Cu_2?xSe phase with increasing heating rate. Scanning electron microscopy (SEM) and XRD showed a remarkable increase in the grain size of CIGS during rapid heating.     

Theoretical study of NO adsorbed on the surface of TiO<Subscript>2</Subscript> (110) cluster model

The chemisorption properties of N¹⁸O adsorption on TiO₂(110) surface were investigated by experimental and theoretical methods. The results of temperature programmed desorption (TPD) indicated that the temperatures of the three desorption peaks of the main N₂ molecules were at (low) temperature of 230 K, 450 K and (high) temperature of 980 K. This meant that N¹⁸O decomposed and recombined during the process of N₂ desorption after N¹⁸O was exposed. Analysis of the stable combination and orbital theory calculation of the surface reaction of NO adsorption on the TiO₂(110) cluster model showed that there was clear preference for the Ti-NO orientation.     

Low-Temperature Selective Catalytic Reduction of NO with NH<Subscript>3</Subscript> over Fe–Ce–O<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> Catalysts

In this study, we used a simple impregnation method to prepare Fe–Ce–O _x catalysts and tested them regarding their low-temperature (200–300 °C) selective catalytic reduction (SCR) of NO using NH₃. We investigated the effects of Fe/Ce molar ratio, the gas hourly space velocity (GHSV), the stability and SO₂/H₂O resistance of the catalysts. The results showed that the FeCe(1:6)O _x (Ce/Fe molar ratio is 1:6) catalyst, which has some ordered parallel channels, exhibited good SCR performance. The FeCe(1:6)O _x catalyst had the highest NO conversion with an activity of 94–99% at temperatures between 200 and 300 °C at a space velocity of 28,800 h^?1. The NO conversion for the FeCe(1:6)O _x catalyst also reached 80–98% between 200 and 300 °C at a space velocity of 204,000 h^?1. In addition, the FeCe(1:6)O _x catalyst demonstrated good stability in a 10-h SCR reaction at 200–300 °C. Even in the presence of SO₂ and H₂O, the FeCe(1:6)O _x catalyst exhibited good SCR performance.     

随机扩增多态性DNA技术研究发现二氧化钛纳米颗粒对西葫芦具有基因毒性

研究目的：二氧化钛（TiO2）纳米颗粒已经广泛应用于化妆品、防晒霜、涂料和牙膏等。这些纳米颗粒性质非常稳定,能在废水和生物固体中转移和分散。现有研究表明,TiO2纳米颗粒对动物正常生理活动具有毒性等负面作用。但是,它们对植物是否具有毒性特别是是否会产生植物基因毒性至今尚不清楚。因此,本文使用随机扩增多态性DNA技术研究TiO2纳米颗粒是否对西葫芦具有基因毒性,为TiO2纳米颗粒排放进入环境后的潜在植物毒性风险评价提供依据。 创新要点：首次发现了TiO2纳米颗粒对西葫芦具有基因毒性。 重要结论：采用随机扩增多态性DNA技术,发现TiO2纳米颗粒污染处理的西葫芦样品与未处理样品的基因组DNA图谱相比,不仅在谱带强度有明显差异,而且存在谱带消失和新谱带产生现象,表明TiO2纳米颗粒对西葫芦具有基因毒性。     

Chemically processed Nb-doped SrTiO3 films and properties

Homogeneous, crack-free SrNb_xTi_1−x O₃ thin films on (110) silicon substrates were successfully fabricated by sol-gel processing. The optimum route and conditions were systematically investigated. Sr(OAc)₂ glacial acctic acid solution, after being refluxed and reacted with tartrate, formed Sr(OAc)₂(C₄H₆O₆)₂; Ti(OBu)₄ formed Ti(OAc)_4−x (AcAc)_x after having the ligand partially exchanged with AcAc, while Nb(OC₂H₅)₅ formed (OAc)₂Nb(AcAc) (C₄H₆O₆) by exchanging of ligand in glacial acetic acid with (CH₃CO)₂O. All the metal species after undergoing partial hydrolysis and polymerization with hydroxyl or oxygen, formed SrNb_xTi_1−x O₁₃ cluster sol. Methyl cellulose (MCL) caused SrNb_xTi_1−x O₃ sol to have polymeric structure and easily form films. SrNb_xTi_1−x O₃ films with perovskite were subsequently formed after being annealed at 650∼750 °C for 60 min in 25% N₂+75% H₂ (volume ratio) atmosphere. Resistivity of the SrNb_0.1Ti_0.9O₃ films at room temperature was 64 μω·cm, a particular T ² temperature dependence of the resistivity, from 25 K up to room temperature, was observed. Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China