脉冲电晕结合Ca(OH)2吸收法脱硫脱硝

Removal of SO2 and NOx by pulsed corona combined with in situ alkali absorption was experimentally investigated.In the reactor,a plate-wire-plate combination is devised for generating pulsed corona and then alkaline absorbent slurries were introduced into the reactor by a continuous band conveying system to capture the gaseous reaction products.It was found that both SO2 and NO could be removed by corona combined with in situ alkali absorption.The removal of SO2 increased to 75%with the corona discharge,compared with 60%removal only with Ca(OH)2 absorption.About 40%removal of NO was reached by pulsed corona combined with in situ Ca(OH)2 absorption.It was found that SO2 and NO in the gas stream are oxidized to SO3 and NO2 by pulsed corona respectively,and then absorbed by the alkali in the reactor.The removals of SO2 as well as NO were higher with Ca(OH)2 as the absorbent,compared with using CaCO3 or ZnO.     

臭氧氧化—钙法吸收同时脱硫脱硝的试验研究

针对国内某石化企业CFB锅炉烟气特点,进行实验室烟气模拟,采用臭氧氧化—钙法吸收同时脱硫脱硝工艺进行小试研究.实验采用臭氧将NO氧化为NO2,再通入鼓泡反应器中与Ca（OH）2浆液发生吸收反应,达到同时脱硫脱硝的目的.实验结果表明：NOx脱除率与臭氧投加量成正比,当臭氧投加量为1.1时,NOx脱除率可达到90％以上;SO2初始浓度的变化对NOx脱除率影响不大;NO初始浓度和烟气含氧量对SO2脱除率影响效果均不显著;烟气含氧量的增大有利于NOx的脱除.     

UV/H2O2高级氧化处理苯酚废水研究

本文采用UV/H2O2实验室装置对苯酚人工配水进行处理试验研究,试验结果表明:在UV灯功率为500W,pH值7.0左右,H2O2:COD摩尔比为2:1,反应240min后COD由1045mg/L降至小于20mg/L,去除率高达99％以上.考察了不同pH(4.0,7.0和9.0),双氧水投加量与投加方式(一次投加和多次投...     

Ca(OH)2粉法脱硫在水泥回转窑系统中的应用

我厂5　000t/d双系列预热器带管道在线分解炉熟料生产线,工厂矿山石灰石氧化钙含量偏低（约43%）,生料配料中石灰石占88%,硅质原料为7%,铝质原料为5%,通过三率值的合理控制,生产线工艺状况良好,熟料质量稳定。自2015年7月1日实施GB4915-2013《水泥工业大气污染物排放标准》后,SO2排放限值降低为200mg/Nm3,时有发生超标现象,为此工厂多方面查找原因和采取措施,取得了较好效果。     

UV/O3/H2O2化学氧化活性艳蓝KN-R

以商品染料活性艳蓝KN-R为研究对象，利用VC／O3/H2O2技术进行氧化处理。考察了染料溶液在此过程中的pH、电导率、COD、TOC和吸光度的变化。经过70min的氧化过程，结果表明，溶液的pH降低、电导率不断升高、色度去除率达98．9％，溶液的COD和TOC去除率分别为47％和5％。VC／O3/H2O2技术与UV/H2O2氧化法相比，UV／O3/H2O2能显著去除染料溶液的色度。     

H2O2/UV流化床氧化焦化废水尾水中惰性成分的可行性考察

焦化废水尾水中残留的多种惰性成分仍然构成环境风险,制约了其安全排放或安全回用,有必要研究可行的深度处理技术。本文以实际废水作为研究对象,采用自行研制的H₂O₂/UV流化床反应器,考察在不同的H₂O₂投加量、pH值、曝气量及光照条件下对COD去除与UV254转化的影响。以TOC为指标评价其矿化程度,并通过UV扫描、HPLC、GC/MS、IC等方法分析惰性成分的氧化效果。结果表明：当初始H₂O₂与COD的摩尔比值约为0.22、微酸性与适当曝气、实现光反射时能够得到高效的污染物转化效率,COD和TOC的浓度可分别下降到20 mg/L 和10 mg/L左右,降解过程中,长链烷烃、含氮杂环化合物、苯系物及多环芳烃等组分被有效转化并矿化,部分转化为小分子中间产物如乙酸等,废水毒性大为降低,可以作为回用的水源。     

H2O2氧化法去除水体中亚硝酸盐和氨的研究

本文用H2O2氧化法和UV（紫外光）-H2O2催化氧化法研究了水体中N煤^-与NH4^ 的氧化，结果表明：NO2^-能被H2O2有效氧化，而NH4^ 几乎不能被H2O2氧化；在UV催化下NO2^-的氧化率有显著提高，NH4^ 的氧化率也有一定程度的提高；共存NH4^ 和NO2^-的氧化没有影响，而在浓度较大时，共存NO2^-对NH4^ 的氧化起着一定的促进作用。     

钛盐光度法测定O3/H2O2高级氧化系统中的过氧化氢

采用钛盐光度法测定O3/H2O2系统中的/H2O2,考察了pH值、O3/H2O2摩尔比、钛盐用量和显色时间的影响,确定了最佳的测定条件;通过加标回收率实验和对比实验,证明了该方法的可靠性.结果表明,pH值为3.0、λ=385nm、草酸钛钾浓度2.5mmol·L-1和显色时间8min条件下,H2O2浓度0～45mg·L-...     

液相氧化吸收法同时脱硫脱硝技术的研究进展

煤燃烧过程中排放的SO2、NOx等是环境污染的主要因素。目前,湿法脱硫技术在我国已广泛应用,在此基础上开发的湿法脱硫协同脱硝技术具有重要意义。重点介绍了国内外几种典型的液相氧化吸收一体化脱硫脱硝技术,包括Na Cl O2法、H2O2法、KMn O4法、Na2S2O8法等。综述了各种方法的研究进展,评述了其各自的特点,并指出上述方法在能耗、污染、成本等方面的问题,有待工业试验的进一步验证。     

UV/H2O2氧化联合CaO吸收脱除NO的传质-反应动力学

在实验室规模的光化学反应器中,基于实验研究﹑动力学理论以及双膜理论,研究了UV/H₂O₂氧化联合CaO吸收(UV/H₂O₂-CaO工艺)脱除燃煤烟气中NO的传质-反应动力学。分析了NO吸收的传质-反应过程,明确了NO吸收过程的主要控制步骤和强化措施,测定了关键的动力学参数,推导了NO吸收过程的理论模型。结果表明:在实验范围内,NO吸收速率随着NO浓度的增加几乎呈线性增加。随着H₂O₂浓度和CaO浓度的增加,NO的吸收速率均呈现先增加后变缓的趋势。UV/H₂O₂-CaO工艺脱除NO是一个拟一级快速反应过程,强化气相主体扰动﹑增加气液接触面积和提高NO分压可有效提高NO的吸收速率。NO吸收速率方程的计算值和实验值具有较好的一致性。     

介质阻挡放电中气体成分对NOx脱除的影响

利用介质阻挡放电(DBD)产生低温等离子体进行烟气的脱硝实验,研究了在乙烯存在的条件下,温度和其他烟气成分对NO_x脱除率的影响。结果表明:随着温度的升高,NO脱除速率增快;模拟烟气中加入CO₂,在能量密度较低时,CO₂作为电负性分子会降低自由基的生成,导致NO的脱除率降低,随着能量密度的升高,CO₂对NO脱除的影响减小;模拟烟气中加入水后可以产生更多的OH、HO₂等自由基,促进NO的氧化;SO₂的加入会与自由基O反应,使初始反应中O与C₂H₄的反应速率减弱,从而影响了NO的氧化速率,但O₃、HO₂等强氧化自由基会优先与NO反应,因此SO₂的加入不会影响NO最终的脱除率。     

Predicting Ca(OH)2 content and chemical shrinkage of hydrating cement pastes using analytical approach

A semiempirical model is proposed to predict the evolution of chemical shrinkage and Ca(OH)₂ content of cement paste at early age of hydration. The model is based on chemical equations and cement compound hydration rates. Chemical shrinkage and Ca(OH)₂ amount are computed using the stoichiometric results of the hydration reactions considered in the model and the density of hydration products and reactants. The model validation is conducted by comparison between computed and experimental results achieved on ordinary cement pastes with different water-to-cement (w/c) ratios (0.25, 0.30, 0.35 and 0.40) cured at 10, 20, 30, 40 and 50 °C, respectively. Hydration degree and Ca(OH)₂ content are determined using the thermogravimetric analysis (TGA) and chemical shrinkage evolution using a gravimetric method.The comparison reveals a good consistency between modelled and experimental data at early age of hydration.     

Characteristics and reactivities of Ca(OH)2/silica fume sorbents for low-temperature flue gas desulfurization

Ca(OH)₂/silica fume sorbents were prepared with various Ca(OH)₂/silica fume weight ratios and slurrying times at 65°C and a water/solid ratio of 10/1. Dry sorbents prepared were characterized, and their reactivities toward SO₂ were measured in a differential fixed-bed reactor at the conditions similar to those in the bag filters in the dry and semidry flue gas desulfurization (FGD) processes. The reaction between Ca(OH)₂ and silica fume in the slurry was very fast. The formation of calcium silicate hydrates, which were mainly C-S-H(I), resulted in sorbent particles with a highly porous structure that seemed compressible under high pressures. The sorbents were mesoporous, and their specific surface areas and pore volumes were much larger than those of Ca(OH)₂ alone. The utilization of Ca of sorbent increased with increasing silica fume content mainly due to the increase in the specific surface area of sorbent. The sorbent with Ca(OH)₂ had the maximum SO₂ capture. Sorbents with Ca(OH)₂ contents less than and greater than would have a SO₂ capture greater than that of Ca(OH)₂ alone. Both the utilization of Ca and SO₂ capture per unit specific surface area of sorbent decreased in general with increasing specific surface area. At the same Ca(OH)₂ content, the utilization of Ca or SO₂ capture of the Ca(OH)₂/silica fume sorbent was greater than that of the Ca(OH)₂/fly ash sorbent; however, the amount of SO₂ captured per unit surface area of the former sorbent was smaller than that of the latter sorbent. The results of this study are useful to the preparation of silica-enhanced sorbents for use in the dry and semidry FGD processes.     

超临界CO2快速膨胀法制备SiO2/聚氨酯超疏水涂层

用超临界CO₂快速膨胀法制备了SiO₂/聚氨酯超疏水涂层。首先用十三氟辛基三乙氧基硅烷（F-硅烷）和γ-(甲基丙烯酰氧基)丙基三甲氧基硅烷（KH-570）改性纳米二氧化硅,制备出含双键的纳米二氧化硅粒子,将其分散在超临界CO₂中,再利用超临界CO₂快速膨胀法将其喷射到双键封端的且已添加了引发剂的聚氨酯涂层表面,通过加热,使纳米二氧化硅粒子接枝在聚氨酯涂层表面,形成稳固粗糙结构,获得了超疏水性质。研究了喷嘴温度、反应釜温度和压力、偶联剂配比、表面粗糙度对涂层疏水性的影响。结果表明：涂层的静态水接触角可达到169.1°±0.6°;在喷嘴和釜内温度都为90℃,釜内压力为16 MPa,F-硅烷和KH-570配比为1∶1,表面粗糙度为7.3 μm时,所制得涂层具有较好的超疏水性,且具有优良的耐刮伤性。该法高效环保,涂层性能优良,适于大面积制备。     

TiO2-V2O5纳米纤维光催化氧化烟气中的Hg0

对静电纺丝法制备的TiO₂和TiO₂-V₂O₅纳米纤维进行光催化脱除模拟烟气中Hg⁰的研究。对纳米纤维进行了SEM、TEM、XRD、BET和UV-Vis检测。结果表明TiO₂-V₂O₅纳米纤维为锐钛矿,V₂O₅高度分散在TiO₂中。纤维直径在200 nm左右,由粒径为10 nm左右的微粒组成。掺杂V₂O₅后,纤维的吸光范围扩大,在可见光范围内的吸光度比纯TiO₂时有了很大提高。实验研究了不同光照条件、V₂O₅的掺杂量和循环次数对脱汞的影响,分析了TiO₂-V₂O₅催化脱汞的机理。当V₂O₅的质量含量为3%时,TiO₂-V₂O₅在可见光下的脱汞率可达到66%,比纯TiO₂时的7%有了显著提高;纤维的脱汞性能稳定,多次循环后紫外光和可见光下的脱汞率仍分别保持在80%和65%左右。电子的跃迁和电子、空穴的快速分离是TiO₂-V₂O₅在可见光下脱汞率提高的主要原因。     

新型CO2低温捕集与N2/O2分离复合系统性能分析

提出了一种CO₂低温捕集液化与N₂/O₂分离的新型复合系统,并且对该系统的性能以及优势进行了分析。这一系统不仅将CO₂低温捕集液化与N₂/O₂的分离结合起来,而且能达到降低能耗与减少投资的目的。采用理论分析和软件模拟相结合的方法,对该系统进行可行性分析。结果显示,这一新型系统不仅能量消耗低于传统醇胺吸收捕集CO₂的系统,该新型复合系统捕集1 t CO₂耗能3.29 GJ·t^-1,而传统MDEA吸收法耗能4.11 GJ·t^-1。而且在该系统中,CO₂分离液化的同时,可以获得副产物N₂与O₂。本研究阐明了一种CO₂低温捕集液化与N₂/O₂分离复合系统的新思想。     

A rate equation for Ca(OH)2 and CO2 reaction in a spouted bed reactor at low gas concentrations

In the present study, the carbonation reaction of hydrated lime in semi-dry condition is investigated experimentally in a laboratory-scale spouted bed reactor. Results show that for operating conditions where the concentration of CO₂ is low, the capture efficiency is raised by increasing the inlet CO₂ concentration. Additionally, because of the inconsistency between the experimental reaction rate and the calculated values based on the previous proposed equations, a new rate equation is introduced that considers the dependency of CO₂ concentration too. To validate the proposed equation, its predictions were compared with another set of experimental data.     

Partial oxidation of ethane by in situ generated H2O2

Selective partial oxidation of ethane to ethanol and acetaldehyde by in situ generated H₂O₂ has been achieved under cathodic current passing through a carbon supported Nafion-H catalytic membrane. A correlation between H₂O₂ generation rate and reaction rate has been found.