臭氧氧化结合化学吸收同时脱硫脱硝的研究

为深入研究和开发臭氧氧化结合化学吸收同时脱除多种污染物技术，阐明了石灰石吸收脱除臭氧氧化产物（SOx和NOx）的吸收反应机理，通过气液固平衡理论对石灰石浆液吸收SOx和NOx特性进行了分析研究。理论分析表明：烟气中CO2对SOx和NOx吸收的影响可以忽略，并给出浆液在吸收容量所能承受的最大气液比。当[CaCO3]=0．05mol／1时，临界点M=600-700；当[CaCO3]=0．1mol／1时，临界点M=1200～1300；当[CaCO3]=0．15mol／1时，临界点M=1900～2000。图4表1参9     

催化裂化烟气排放控制技术现状及面临问题的分析

国内催化裂化装置再生烟气SOx、NOx排放限值相关的国家政策以及国家标准、地方标准日益严格,催化裂化烟气脱NOx即将纳入强制执行规范.介绍了国内催化裂化烟气的特点、相关排放标准以及主要的污染物排放控制技术的特点和发展现状.当催化原料油硫含量在0.12％～0.50％时,宜采用脱SOx助剂技术;在0.25％～1.50％时,宜采用洗涤脱SOx技术;在0.75％～3.00％时,宜采用回收法脱SOx技术.SCR工艺被证明是应用最多且NOx脱除效率最高、最为成熟的脱NOx技术.分析了主流脱SOx、脱NOx技术的工程方面问题:钠碱洗涤法脱SOx技术面临消耗碱和含盐污水排放的问题;钠钙双碱法脱SOx技术则面临脱硫石膏质量和CO2排放的问题;臭氧氧化法(LoTOxTM)脱NOx技术面临电耗量大和臭氧成本高的问题;海水洗涤法受地域制约且不能处理高含硫烟气;使用脱SOx、脱NOx助剂也有一定局限性.展望了资源化烟气脱SOx、选择性催化还原脱NOx、一体化催化烟气脱除有害污染物的应用前景.     

船舶尾气臭氧氧化-海水吸收的脱硫脱硝新工艺研究

通过模拟试验研究了臭氧氧化结合海水吸收同时脱除船用发动机排气中SO2和NO2的新工艺.在管式反应器内研究了反应温度、n(O3)/n(NO)(物质的量之比)、碳氢、SO2等对臭氧氧化NO的影响,并对模拟尾气进行了臭氧氧化结合海水吸收的脱硫脱硝试验.结果表明,n(O3)/n(NO)对臭氧氧化NO影响很大,NO氧化率随n(O3)/n(NO)呈线性增长,n(O3)/n(NO)为1,反应温度分别为常温、150℃和200℃时,NO氧化率分别达到99.0%、98.3%和98.1%;反应温度低于200℃时,温度对臭氧氧化NO影响很小,而当反应温度升至275℃时,NO氧化率明显下降,这与臭氧在较高温度下分解有关;SO2在O3/NO/SO2/N2/O2体系和O3/NO/C2H4/SO2/N2/O2体系中对臭氧氧化NO都没有影响;200℃以下,C2H4对臭氧氧化NO影响很小,而在275 ℃时,C2H4对臭氧氧化NO有一定促进作用;模拟尾气经臭氧氧化-海水吸收后,脱硫率为98.5%,n(O3)/n(NO)为1时的脱硝率为91.05,NO能耗为56.4 g、(kW·h).     

液气比对石灰石-石膏湿法烟气脱硫过程的影响

石灰石-石膏湿法烟气脱硫系统中,液气比是影响系统脱硫性能及经济性的重要参数.利用所建立的并流有序降膜式湿法脱硫装置,进行了液气比对石灰石-石膏湿法脱硫过程影响的试验研究.结果表明:脱硫率随液气比增加而增加;当液气比小于8 L/m3时,增加液气比能更有效地提高脱硫率;液气比增加,吸收塔吸收段出入口的浆液中石灰石浓度差降低,吸收段内浆液中石灰石溶解量增加,浆液中石灰石浓度增加.     

基于尿素/NaClO_2溶液湿法烟气同时脱硫脱硝的研究

结合燃煤电厂实际工况条件,基于尿素/NaClO2溶液进行了同时脱硫脱硝试验研究,探索尿素/NaClO2湿法同时脱硫脱硝的主要影响因素和优化工艺条件,并分析其反应机理.结果表明:纯尿素溶液可有效脱除烟气中的SO2,但对NO脱除效果较差,NaClO2的添加可有效改善NO的脱除效果;液气比和NaClO2质量分数增大有利于提高尿素/NaClO2溶液的脱硫脱硝效果,其中NaClO2质量分数对NO脱除效率的影响比对SO2脱除效率的影响明显;空塔气速和NO初始质量浓度与系统脱硫、脱硝效率成负相关关系.NaClO2的添加对尿素溶液脱硫效果影响较小,SO2被吸收后生成的SO2-3主要被烟气中溶于水的O2氧化成SO2-4;难溶于水的NO被NaClO2氧化为NO2和NO-2等,进而被尿素溶液有效吸收,NOx最终多数以N2形式排放.     

脱硫脱硝经济性分析

煤炭的燃烧释放大量的SOx和NOx,目前的分段脱除技术设备造价昂贵,运行费用高,难以实现大规模普及。文章将循环经济发展较好的氨法及尿素法同时脱硫脱硝技术与传统的石灰、石灰石脱硫-SCR技术进行了经济性比较。分析结果表明：氨法仅为石灰石、石膏法脱硫-SCR法联合脱硫脱硝运行费用的20.9%,尿素法为其52.1%。最后对氨及尿素湿法同时脱硫脱硝技术的应用前景进行了展望,并指出了存在的问题和进一步研究的方向。     

基于尿素/NaClO2溶液湿法烟气同时脱硫脱硝的研究

结合燃煤电厂实际工况条件,基于尿素/NaClO2溶液进行了同时脱硫脱硝试验研究,探索尿素/NaClO2湿法同时脱硫脱硝的主要影响因素和优化工艺条件,并分析其反应机理.结果表明:纯尿素溶液可有效脱除烟气中的SO2,但对NO脱除效果较差,NaClO2的添加可有效改善NO的脱除效果;液气比和NaClO2质量分数增大有利于提高尿素/NaClO2溶液的脱硫脱硝效果,其中NaClO2质量分数对NO脱除效率的影响比对SO2脱除效率的影响明显;空塔气速和NO初始质量浓度与系统脱硫、脱硝效率成负相关关系.NaClO2的添加对尿素溶液脱硫效果影响较小,SO2被吸收后生成的SO32-主要被烟气中溶于水的O2氧化成SO42-;难溶于水的NO被NaClO2氧化为NO2和NO2-等,进而被尿素溶液有效吸收,NOx最终多数以N2形式排放.     

氨水富液再生及再生液吸收特性的试验研究

在常压、60～90℃下通过试验系统对氨水吸收CO2后的富液的再生特性以及再生液的吸收能力进行了研究,得到了影响氨水富液再生的因素及再生液的吸收性能.结果表明:提高再生温度可以增大CO2的再生速率和再生程度;氨水富液负荷对再生有很大影响,负荷低于0.4 molCO2/mol NH3时,再生率维持在较低水平,随后再生率随负荷上升而线性增加;负荷为0.6 molCO2/mol NH3时,氨水富液已基本丧失脱碳能力,再生后其吸收性能得到一定恢复;在再生液中添加少量的新鲜氨水,有助于恢复再生液对CO2的吸收能力;综合考虑富液再生与再生液吸收两方面,推荐氨水循环脱碳时负荷变化范围为富液0.6 mol CO2/mol NH3,贫液0.4 mol CO2/mol NH3.     

空塔截面气速对石灰石/石膏湿法烟气脱硫过程的影响

利用建立的并流有序降膜式湿法脱硫装置,进行了空塔截面气速对石灰石/石膏湿法脱硫过程影响的试验研究.结果表明:空塔截面气速增加,脱硫率下降;但由于气、液相传质速率提高,脱硫率下降较缓慢;吸收塔吸收段出入口浆液中石灰石浓度差及吸收段内浆液中石灰石溶解量增加,脱硫率增加明显;循环槽内浆液S4-浓度略有增加,吸收塔吸收段内浆液中S4-浓度及循环槽内Ca2 浓度增加.     

臭氧耦合双金属催化剂共同氧化NO和VOC的研究

通过等体积浸渍法合成一系列M-MnO_x/γ-Al₂O₃催化剂(M=Ce、Co、Cr、Fe),用于低温催化臭氧共同氧化NO和邻二甲苯(o-C₈H₁₀)的研究,试验发现,Fe/Mn催化剂表现出最高的催化氧化活性,最佳的温度区间为60～100℃;在NO与邻二甲苯共同存在时,臭氧优先将NO氧化为NO₂,之后NO₂深度氧化与邻二甲苯初步氧化同时进行,最后多余的臭氧将邻二甲苯初步氧化生成的小分子有机物氧化为CO与CO₂;催化剂对不同初始污染物浓度适应性良好,研究结果可为臭氧一体化脱除烟气污染物的工业化推广应用提供依据。     

雾化NaOH溶液吸收SO2的实验研究

对竖直圊管实验段中喷入雾化的NaOH溶液吸收烟气中的SO2气体做了实验研究，并分析了影响SO2吸收率的多种因素如(2OH-)／SO2、烟气进口温度、入口SO2摩尔分数、雾化空气量及烟气的流速等等，实验结果为实际的脱硫装置的设计及运行提供了基础数据。     

Single stage and double absorption heat transformers in an industrial application

An industrial application of the single stage and double absorption heat transformer (AHT) systems using water–lithium bromide solutions with water as the refrigerant was analyzed. First, a basic single stage AHT system was described, the operating sequence was explained and thermodynamic system analysis was presented. Next, an application of the single stage AHT system to an industrial company was analyzed. A computer code was prepared to determine the effect of different parameters on the AHT system performance and the results were presented in graphical form. Additionally, the series and parallel double absorption AHT systems were introduced, the operating sequences were explained and thermodynamic system analysis was included. All results were presented in tabular form for comparison. It is concluded that about 50% of the waste heat can be utilized and the hot process water and vapor could be produced by applying single stage and double AHT systems, respectively. The parallel double AHT system could generate more vapor than the series double AHT system. Copyright © 2009 John Wiley & Sons, Ltd.     

膜吸收法与化学吸收法分离烟气中CO2的试验比较

在中空纤维膜接触器和化学吸收填料塔试验台上,采用膜吸收法和化学吸收法分别进行了分离模拟烟气中CO2的性能试验比较.采用MEA水溶液作为吸收液,重点考察了在不同吸收液流量、温度和烟气流量条件下2种吸收法对CO2的脱除效率和吸收液CO2负荷.结果表明:在不同工况下,膜吸收法对于CO2的脱除效率均好于化学吸收法,而吸收液CO2负荷则表现出不同趋势.     

Experimental study on the temperature dependence of ultraviolet absorption cross-sections of sulfur dioxide

The photoabsorption cross-sections of sulfur dioxide were measured in the spectral regions of 200–230 nm and 275–315 nm at 298–415 K, using a grating monochromator with a resolution of 0.2 nm. The discrete absorption cross-section is directly correlated with the number of quantum excited from the base state. The absorption cross-sections at the peaks of discrete bands decreased linearly with the increase of temperature, which corresponded to the decrease in the population of vibrational and rotational transitions from the base level to higher excitation levels. The absorption cross-section peaks decreased linearly when the temperature increased from 298 to 415 K, with relative drops of 74.0% and 75.8% at 200–230 nm and 275–315 nm, respectively. Another distinctive feature of sulfur dioxide absorption spectra in the above two spectral regions was the quasiperiodic structure of the absorption peaks, whose equal wavelength intervals were 1.53 nm and 1.95 nm, respectively. Red and blue shifts were not found at the absorption peak positions. __________ Translated from Journal of Zhejiang University (Engineering Science), 2007, 41(2): 329–332 [译自: 浙江大学学报(工学版)]     

Enhancement of steam absorption into a film of LiBr aqueous solution falling over a downward‐facing plate

An experimental study was performed on the enhancement of steam absorption into a LiBr aqueous solution. The enhancement method proposed here is to set an absorption heat transfer plate facing downward to generate free convection within a liquid film falling over the plate. The experiment was conducted varying the tilt angle of the heat transfer plate in a range of 40 to 90°. The heat transfer coefficients were compared for both cases of the heat transfer plate facing upward and downward. It was found from the experimental results that the downward‐facing plate has a higher heat transfer coefficient than the upward‐facing plate, which confirmed that free convection and mixing occur in the liquid film and enhance the absorption heat transfer in the case of the downward‐facing plate. The enhancement effect becomes remarkable as the tilt angle approaches horizontal, though the liquid film becomes thick and its thermal resistance increases. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(8): 606–616, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10062     

溴化锂水溶液的结晶控制及应用对策

从应用实例出发,对溴化锂吸收式制冷机组运行时可能发生的溶液结晶现象,以及溴化锂水溶液的结晶机理进行分析,并提出溴化锂水溶液的结晶的应用对策,部分机组运行验证的结果表明这种策略可行.     

The effects of gas-phase and in-depth radiation absorption on ignition and steady burning rate of PMMA

Although well studied, there are still interesting features about the ignition and steady burning rate behaviour of PMMA when heated by thermal radiation. In this contribution, the dependence on external heat flux of ignition delay time and steady mass flux of PMMA are investigated numerically. Ignition is modelled by the critical mass flux criterion. The heat transfer model includes effects of heat lost by out gassing, change of volume during degradation and absorption of radiation in both condensed and gaseous phases. Model results are compared to experimental data for both ignition delay time and quasi-steady mass flux across a range of heat fluxes from 20 to 210 kW m⁻² and the importance of both gas-phase and condensed-phase radiation absorption effects are discussed.     

太阳光谱选择性吸收涂层制备工艺探讨

探讨粘结层、吸收层、减反射层的制备工艺及基底粗糙度状态对太阳选择性吸收涂层性能的影响。采用磁控溅射法,以SS/AlN涂层为例,制备太阳光谱选择性吸收涂层,并测试性能。结果表明：合适的制备工艺可以提高膜层的结合力和涂层的整体性能,胶带粘贴无脱落,吸收比96%,500℃发射比10.5%,并证实基底的粗糙度对涂层的发射率基本无影响。     

新型太阳能吸收式制冷循环的性能分析

在两级溴化锂吸收式制冷循环的基础上,提出了一种由太阳能驱动的新型吸收式制冷循环,并对其进行性能分析。通过大量计算,分析结果表明,在现有太阳能集热器所能提供的热水温度范围内,新型太阳能吸收式制冷循环有较高的热力系数。该循环系统的中间压力、中间浓度对系统的热力系数和热源可利用温差有较大影响。     

吸收式太阳能海水淡化系统中降膜吸收与再生过程研究

针对吸收式太阳能海水淡化系统设计了降膜吸收、再生实验装置,分别以溴化锂、氯化钙两种溶液为工质对装置进行了实验研究。通过改变影响工质吸收与再生性能的条件(如溶液浓度和温度等),给出了不同工况下系统的运行情况。实验结果表明,当运行压力低于20kPa、热源温度高于75℃时溶液已有较好的再生速率,而当海水蒸发温度高于45℃时,溶液也已有较好的吸收速率,完全满足太阳能集热系统供热要求。还给出了系统最佳运行参数范围。