Assessment of NH3 Reduction and N2O Production during Treatment of Exhausted Air from Fattening Pigs Building by a Commercial Scrubber

The use of air scrubbers to reduce ammonia (NH3) emissions from buildings on pig farms is one of the most promising techniques in the GÖteborg protocol and other European regulations including the Industrial Emission Directive. In France, some air scrubbers are currently used on pig farms, mainly to reduce odours from livestock buildings. However, recent research revealed the production of N2O resulting from the treatment of air from pig buildings. In this context, a two-month study was conducted on a pig farm with 750 places for fattening pigs to check the abatement of NH3 emissions and to assess the possible production of N2O during treatment of exhausted air from buildings housing fattening pigs by a air scrubber. Concentrations of NH3 and N2O in the inlet and outlet air of the scrubber were continuously monitored using an Innova 1412 infrared analyzer. With the scrubber operating parameters (airflow, design, size), our results confirmed the production of N2O in the order of 5% of NH3-N reduced. N2O was produced by biological nitrification and/or denitrification inside the air scrubber. Statistical analysis (Pearson’s test) showed that the production of N2O was strongly influenced by the rate of airflow and the outside temperature. The abatement of NH3 emissions from the building was only 33%, i.e. much lower than the 70% - 90% usually cited in the literature.

Enhancing the crystalline degree of carbon nanotubes by acid treatment, air oxidization and heat treatment

Three approaches of treating carbon nanotubes (CNTs) including acid treatment, air oxidization and heat treatment at high temperature were studied to enhance the crystalline degree of carbon nanotubes. High temperature heat-treatment elevates the crystalline degree of carbon nanotubes. Acid treatment removes parts of amorphous carbonaceous matter through its oxidization effect. Air oxidization disperses carbon nanotubes and amorphous carbonaceous matter. The treatment of combining acid treatment with heat-treatment further elevates the crystalline degree of carbon nanotubes comparing with acid treatment or heat-treatment. The combination of the three treatments creates the thorough effects of enhancing the crystalline degree of carbon nanotubes.

Effect of Air Pressure on Hardened Layer of U75V 60 kg/m Heavy Rail after Heat Treatment

The samples cut from U75V 60 kg/m heavy rail are heated to 900 ℃ in resistance furnace and then put into air spraying channel to be cooled for 80 s, and change air pressure from 0.16 MPa to 0.33 MPa, and observe the effect of air pressure on hardened layer. The thickness and hardness of hardened layer increases with the increase of air pressure, and the thickness is more than 24 mm at the center and top fillets of rail head, and more than 15 mm at the blow fillets of rail head when air pressure is more than 0.26 MPa. During the tempering after heat treatment, tempering temperature of rail head is more than 570 ℃ when air pressure is separately 0.16 MPa, 0.20 MPa and 0.23 MPa, which is higher than finishing temperature of pearlite transformation at the cooling rate of 3 ℃/s according to CCT curve of U75V steel. When air pressure is separately 0.26, 0.30 and 0.33 MPa, the tempering temperature is 529 ℃ lower than finishing temperature of pearlite transformation at the cooling rate of 3 ℃/s. Under this condition, pearlite transformation is finished totally, so in order to reduce air consumption and control the cost, proper air pressure for U75V 60 kg/m heavy rail heat treating should be 0.26 MPa; the cooling rate increases with the increase of air pressure, and the average cooling rate on the surface of rail head is more than 3.21 ℃/s when air pressure is more than 0.26 MPa, and the largest cooling rate occurs at the top fillets of rail head.

Treatment of desizing wastewater from the textile industry by wet air oxidation

This paper describes the application of wet air oxidation to the treatment of desizing wastewater from two textile companies. A two\|liter high temperature, high pressure autoclave reactor was used in the study. The range of operating temperatures examined was between 150 and 290℃, and the partial pressure of oxygen ranged from 0.375 to 2.25 MPa. Variations in pH, COD Cr and TOD content were monitored during each experiment and used to assess the extent of conversion of the process. The effects of temperature, pressure and reaction time were explored extensively. More than 90% COD Cr reduction and 80% TOC removal have been obtained. The results have also been demonstrated that WAO is a suitable pre\|treatment methods due to improvement of the BOD\-5/COD\-\{Cr\} ratio of desizing wastewater. The reaction kinetics of wet air oxidation of desizing wastewater has been proved to be two steps, a fast reaction followed by a slow reaction stage.

Humid Air Plasma Treatment of Birnessite Surface: Application to the Removal of Cochineal Red

The thin layers of birnessite (Mn7O13?5H2O) are exposed to reactive species gliding arc plasma in humid air, which induces the treatment of the thin layers surface. Plasma treatment thin layer of birnessite was used for the degradation of Cochineal Red. The experimental results showed that 95% of the CR solution was completely decolorized by thin layer of birnessite treated by plasma compared to 80% of the same solution after interaction of thin layer of birnessite untreated. The decay kinetics always follows a pseudo-first order reaction. The application of the humid air plasma for the surface treatment of thin layers of birnessite improves the efficiency of treatment for Cochineal Red degradation.

SO_2/Air法处理含氰尾矿浆氧化反应器的设计与应用

介绍了含氰尾矿浆的SO_2/Air法处理技术现状,以及实现该技术应用的氧化反应器高效节能设计原理、反应器的结构设计计算与该技术工艺主要设备的选型方法。通过采用含有SO_2焙烧尾气处理含氰尾矿浆工业应用实例及同等工艺条件下与搅拌槽对比扩大试验表明,采用该氧化反应器进行分步吸收氧化,有助于提高反应效率,增大处理规模,降低系统能耗。

Plasma induced degradation of Indigo Carmine by bipolar pulsed dielectric barrier discharge(DBD) in the water-air mixture

Degradation of the Indigo Carmine(IC) by the bipolar pulsed DBD in water-air mixture was studied. Effects of various parameters such as gas flow rate, solution conductivity, pulse repetitive rate and ect., on color removal efficiency of dying wastewater were investigated. Concentrations of gas phase O 3 and aqueous phase H 2O 2 under various conditions were measured. Experimental results showed that air bubbling facilitates the breakdown of water and promotes generation of chemically active species. Color removal efficiency of IC solution can be greatly improved by the air aeration under various solution conductivities. Decolorization efficiency increases with the increase of the gas flow rate, and decreases with the increase of the initial solution conductivity. A higher pulse repetitive rate and a larger pulse capacitor C\-p are favorable for the decolorization process. Ozone and hydrogen peroxide formed decreases with the increase of initial solution conductivity. In addition, preliminary analysis of the decolorization mechanisms is given.

Catalytic wet air oxidation of phenol over RuO_2/γ-Al_2O_3 catalyst

A kind of CWAO catalyst, RuO_2/γ-Al_2O_3, was prepared by dipping Al_2O_3into the aqueous solution of RuCl_3·3H_2O. XRD, SEM and TEM were used to determine the catalyticstructure. Influences of the calcination temperature, the initial pH of the feed solution anddegradation temperature on the activity of the RuO_2/γ-Al_2O_3 catalyst were investigated and thereaction mechanism was preliminarily studied. Results showed that uniform dispersion of RuO_2crystallites was observed on the surface of the catalyst. The activity of the catalyst was higher atcalcination temperature of 300℃ for 3 h and the particle reunion occurred and some large RuO_2crystallites were abundant at high calcination temperature of 500℃ The activity of the catalyst wasbetter in the acid solution than in the alkaline solution. Increasing degradation temperature andusing the catalyst could shorten the induction periods so that the phenol and COD removal wereincreased. For RuO_2/γ-Al_2O_3 catalyst, the phenol and COD removal were respectively 98% and 80%in a temperature of 150℃, pH of 5.6 and pressure of 3 MPa after a 2 h reaction. This indicated thatRu/γ-Al_2O_3 catalyst had good activity.

Effects of Heat-treatment on Crystallization and Wear Property of Plasma Sprayed Fe-based Amorphous Coatings

The Fe-based amorphous coatings were produced by air plasma spraying. The as-sprayed coatings were heat-treated at the temperature of 573, 873, and 1 023 K, respectively. The crystallization and wear behavior of the heat-treated amorphous coatings were investigated. It was found that the amorphous- nanocrystalline transformation appeared when the as-sprayed coatings were treated at 853 K. The crystallization process had completed and a coating with microcrystallines was formed when the treatment temperature reached 1 023 K. The resultant amorphous and nanocrystalline composite coatings exhibited superior wear resistance compared to crystalline coating. It is attributed to fine grain strengthening of formed nanocrystallines.

Electro-Hydrodynamics and Kinetic Modeling of Dry and Humid Air Flows Activated by Corona Discharges

The present work is devoted to the 2D simulation of a point-to-plane Atmospheric Corona Discharge Reactor （ACDR） powered by a DC high voltage supply. The corona reactor is periodically crossed by thin mono filamentary streamers with a natural repetition frequency of some tens of kHz. The study compares the results obtained in dry air and in air mixed with a small amount of water vapour （humid air）. The simulation involves the electro-dynamics~ chemical kinetics and neutral gas hydrodynamics phenomena that influence the kinetics of the chemical species transformation. Each discharge lasts about one hundred of a nanosecond while the post- discharge occurring between two successive discharges lasts one hundred of a microsecond. The ACDR is crossed by a lateral dry or humid air flow initially polluted with 400 ppm of NO. After 5 ms, the time corresponding to the occurrence of 50 successive discharge/post-discharge phases, a higher NO removal rate and a lower ozone production rate are found in humid air. This change is due to the presence of the HO2 species formed from the H primary radical in the discharge zone.

Evaluation and Commissioning of Commercial Monte Carlo Dose Algorithm for Air Cavity

The purpose of this study was to compare the Pencil Beam (PB) with Monte Carlo (MC) calculated dosimetric results using phantoms for air cavity region. Measurements in Tough water phantom with air gaps were used to verify the calculated dose. The plane-parallel ionization chamber was moved from 2 mm to 20 mm behind air gap. Calculations were performed for various air gaps (1.0, 2.0, 3.0 and 4.0 cm) and field sizes (4.2 × 4.2, 6.0 × 6.0 and 9.8 × 9.8 cm2). The lateral missing tissue measurement was performed using the radiochromic RT-QA film. Dose difference between PB and chamber measurement near an air gap was greater for smaller field size, larger air gap thickness, and shallower depth behind air gap. As the distance from the phantom edge became shorter, the dose differences of the PB calculation and film measurement became larger. MC calculations were found within 3% agreement to the measured dose distributions. Our results demonstrate an excellent agreement between ionization chamber and radiochromic RT-QA film measurements and MC calculations.

The Best Available Technology of Water/Wastewater Treatment and Seawater Desalination: Simulation of the Open Sky Seawater Distillation

This review suggests the concept of the best available technology of water/wastewater treatment and seawater desalination which is in fact a simulation of the seawater distillation at the open sky: coagulation in salty water aerated basin/ coagulation using seawater as coagulant solution with distillation using stored solar energy followed by waterfall on a natural mountain. This natural, green, and technico-economical technology is composed of three steps: the first one is coagulation which may be achieved: 1) in salty water aerated basin (air stripping, AS;dissolved air flotation, DAF) where the raw water is “diluted” in seawater;or 2) in “conventional” coagulation using seawater as coagulant solution instead of alum/ferric salts. The first option seems to be more natural as it simulates river water dilution in seawater and the second one is more practical for “rapid” water consummation. For colloids and microorganisms’ removal, double-layer compression and charge neutralisation, as main coagulation and disinfection mechanisms, would be involved in the first and second options, respectively. Aerated basin (AS/DAF) reproduces the natural aeration to simulate healthy natural water basin. Using stored solar energy, distillation as the best liquid-solid/liquid-liquid separation process provides the removal of dissolved pollutants. For well balanced calco-carbonic equilibrium, the last step of this green treatment is the waterfall on a natural mountain providing useful gases, dissolved oxygen and carbon dioxide, and mineral salts to the water.

The surface treatment on oxide film of pure titanium Part 2.Ceramization of anodic oxide film

目的:用有氧加热处理阳极氧化膜以进一步提高纯钛的耐腐蚀性。材料和方法:6片直径9 mm厚2 mm的纯钛片经阳极氧化处理24 v 10 min后置于烤瓷炉,在有氧环境中加热至400℃(A)、420℃(B)、450℃(C)、500℃(D)、700℃(E)、915℃(F),分别维持40 min,用X线衍射和电化学法检测氧化膜的微观结构和耐腐蚀性,再将样本A和E在上述条件下分别在加热40 min,重复以上检测。结果:加热400℃维持40 min的阳极氧化样品的耐腐蚀性最好,过高的加热温度和加热时间都会破坏氧化膜的耐腐蚀性。结论:阳极氧化结合有氧加热处理是一种较好的提高纯钛氧化膜的耐腐蚀性的方法。

马钢2×380m^(2)烧结机节能减排实践

为进一步适应烧结生产优质、降耗、减排的发展的需求,马钢2×380m^(2)烧结机采取了一系列提质降耗技术措施。通过持续优化厚料层烧结生产经济潜力;降低固体燃耗;点火炉升级改造、带冷机改环冷机、烧结机漏风治理、大型风机变频技术等多项节能新技术的应用以及创新管理,在烧结矿质量以及节能降耗方面取得了显著改善效果,工序能耗由55 kgce/t下降至47kgce/t水平。同时对当前2×380m^(2)烧结机烧结高效、低耗生产存在的问题提出了改进方向,以进一步促进节能减排工作的持续发展。

Cause Analysis and Treatment Measures for Leakage of Top Cover of 330kV GIS Equipment

Based on the experience of GIS equipment maintenance, the causes of air leakage defects of GIS equipment running in a 330 substation were analyzed. After the equipment was disassembled, the main causes of air leakage were found, and a series of improvement measures were taken to eliminate the GIS equipment leakage defect. And the effective and feasible advice was put forward for this type of air leakage problem. The results lay a foundation for the safe and stable operation of GIS equipment.

Oxidative Degradation of 2,4,6-Trichlorophenolin the Presence of Air Ions

2,4,6-trichlorophenol (TCP) was firstly treated with air ions generated by electric discharge, and high dechlorination (53%) was observed after 60 min treatment, indicating that air ions are an efficient dechlorination means and might have a future in the oxidative removal of chlorinated phenols. In addition, a stepwise degradation of TCP, beginning with the formation of a major product 2,6-dichloro-1,4-benzenediol via substitution, is proposed through a detailed analysis of gas chromatography/mass spectrometry.

Development of a Coil-Shape Photocatalysis-Plasma Synergistic Reactor for a Practical and Long-Term Usable Air-Cleaner

A novel air-cleaner with a coil-shape photocatalysis-plasma synergistic reactor was developed. The air-cleaner showed 95% ± 1% reduction of a TVOCs concentration in tobacco smoke at “single-pass” condition. Air-purification activity of the air-cleaner was stably-maintained after the treatment of 12,000 cigarettes of tobacco smoke.

The Impact of Small Field’s Off-Set on Output Factor in Intensity Modulated Radiation Treatment

In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for extremely small and/or severe irregularly shaped fields. The air scatter data are involved directly or indirectly in obtaining the output. Despite the fact that extensive data have been published in many studies to provide a guide on the magnitude of output factor for clinical accelerators, there are very few data reviewed about output factor in-air or phantom for off-set fields. This study was aimed to investigate the impact of these conditions for small fields. This study was conducted in Elekta Synergy linear accelerator which produces 6 MV X-ray energy. The in-air output factor (Sc) has been measured by CC04 ion chamber with brass-alloy “build-up” cap and Dose-1 electrometer, and the total output (Scp) measurements were carried on at dose maximum depth in phantom by the same chamber and Thermoluminescence dosimeter (TLD) for 1 - 10 cm2 fields. The all measurements at center of isocenter and off-set fields at three directions (X2, Y1, Diagonal) were done. By decreasing field size from 10 to 2 cm2 at isocenter, the Sc value using CC04 was decreased to 5.4% and Scp using CC04 and TLD to 14.5% and 11% respectively. By increasing off-set value, the Sc and Scp values were increased in all directions comparing to central fields. The maximum increase was obtained in Y1 direction for Sc and Scp. TLD results for Scp is slightly higher than CC04. The dosimetric properties of small fields and their off-set should be evaluated and modelled appropriately in the treatment planning system to ensure accurate dose calculation in Intensity Modulated Radiation Treatment.

空气加压法在腹腔镜腹壁嵌顿疝修补术中的疗效分析

目的:探讨空气加压法在腹腔镜腹壁嵌顿疝修补术中的临床疗效。方法:回顾分析2020年6月至2022年6月收治的16例腹壁嵌顿疝患者的临床资料,其中腹壁疝8例(侧腹壁切口疝4例,中线切口疝2例,造口旁疝2例),脐疝8例。在空气加压法辅助下行腹腔镜手术,分析手术时间、术中疝大小与还纳情况、术后排气时间、住院时间、并发症等相关指标。结果:16例患者均在空气加压法辅助下顺利完成嵌顿疝的还纳与修补。手术时间85~220 min,平均(154.70±39.06)min,还纳疝内容物时间(18.35±4.98)min,疝环口直径3~10 cm。16例患者均伴有小肠嵌顿,5例肠管坏死中转开腹,行小肠切除术;术中发现隐匿性缺损2例。术后排气时间1~5 d,平均(3.00±1.08)d;术后疼痛评分(3.56±4.01)分,予以对症治疗后疼痛缓解。术后住院3~10 d,平均(6.27±1.93)d。随访8~32个月,中位随访时间24个月,均未出现切口感染、肠梗阻、补片感染、复发等并发症。结论:熟练掌握腹腔镜疝修补术技巧,严格掌握手术适应证,空气加压法辅助腹腔镜手术治疗腹壁嵌顿疝是安全、可行的,值得推广。

中国城市生活垃圾填埋CH_(4)和VOCs等气体排放特征

为全面评估中国城市生活垃圾填埋处理CH4和VOCs等典型大气污染物排放状况,积极推动减污降碳工作,通过统计全国695个城市的基础信息,基于排放因子法,计算了2002~2022年中国城市生活垃圾填埋处理CH_(4)和VOCs等典型大气污染物排放量,分析了排放趋势和空间特征,并提出了减排建议.结果表明:2009年以后中国城市生活垃圾填埋处理率(生活垃圾填埋处理量/无害化处理量)呈持续下降趋势,下降率最低是2011年为1.39%,最高是2020年为12.45%.2022年,中国城市生活垃圾填埋处理排放的CH_(4)、NH_(3)、VOCs、TSP、PM_(10)和PM_(2.5)总量分别为4.09×10^(6),17.04,4.75×10^(4),14.09,6.66和1.00t.空间来看,中国城市生活垃圾填埋处理CH_(4)和VOCs等典型大气污染物排放量高值区向南部变化.2018年以后,大气污染物排放量呈持续下降趋势,下降率最低是2018年为2.75%,最高是2022年为41.57%.2020年以后,CH_(4)排放量呈持续下降趋势,下降率最低是2020年为4.53%,最高是2022年为13.56%.中国城市生活垃圾填埋处理的CH_(4)和VOCs等典型大气污染物排放量在近年来呈现下降趋势,随着生活垃圾填埋量的减少,大气污染物的下降速率大于CH_(4)的下降速率.