Simultaneous desulfurization and denitrification of sintering flue gas via composite absorbent

Experiments on simultaneous absorption of SO_2 and NO_X from sintering flue gas via a composite absorbent NaClO_2/NaClO were carried out. The effects of various operating parameters such as NaClO_2 concentration(ms), NaClO concentration(mp), molar ratio of NaClO_2/NaClO(M), solution temperature(TR), initial solution pH, gas flow(Vg) and inlet concentration of SO_2(CS) and NO(CN) on the removal efficiencies of SO_2 and NO were discussed. The optimal experimental conditions were determined to be initial solution pH = 6, TR=55 °C and M = 1.3 under which the average efficiencies of desulfurization and denitrification could reach99.7% and 90.8%, respectively. Moreover, according to the analysis of reaction products, it was found that adding NaClO to NaClO_2 aqueous solution is favorable for the generation of ClO_2 and Cl_2 which have significant effect on desulfurization and denitrification. Finally, engineering experiments were performed and obtained good results demonstrating that this method is practicable and promising.

Simultaneous desulfurization and denitrification of flue gas by pre-ozonation combined with ammonia absorption

A process of simultaneous desulfurization and denitrification of flue gas was conducted in this study.The flue gas containing 200 mg·m^-3NO,1000-4000 mg·m^-3SO(2,)3%-9%O(2)and 10%-20%CO(2)was first oxidized b(y)O3 and then absorbed by ammonia in a bubbling reactor.Increasing the ammonia concentration or the SO2 content in flue gas can promote the absorption of NOx and extend the effective absorption time.On the contrary,both increasing the absorbent temperature or the O(2)content shorten the effective absorption time of NO((x.))The change of solution pH had substantial influence on NOx absorption.In the presence of CO(2)the NOx removal efficiency reached 89.2%when the absorbent temperature was raised to 60℃and the effective absorption time can be maintained for 8 h,which attribute to the buffering effect in the absorbent.Besides,both the addition of Na(2)S2 O3 and urea can promote the NOx removal efficiency when the absorbent temperature is 25℃and the addition of Na(2)S2 O3 had achieved better results.The advantage of adding Na(2)S2 O3 became less evident at higher absorbent temperature and coexistence of CO(2.)In all experiments,SO(2)removal efficiency was always above 99%,and it was basically not affected by the above factors.

Ternary System of Fe-based Ionic Liquid,Ethanol and Water for Wet Flue Gas Desulfurization

Fe-based ionic liquid （Fe-IL） was synthesized by mixing FeCl3·6H2O and 1-butyl-3-methylimidazolium chloride [Bmim]C1 in this paper. The phase diagram of a ternary Fe-IL, ethanol and water system was investigated to construct a ternary desulfurization solution for wet flue gas desulfurization. The effects of flow rate and concentration of SO2, reaction temperature, pH and Fe-IL fraction in aqueous desulfurization solution on the desulfiariza- tion efficiency were investigated. The results shows that the best composition of ternary desulfurization solution of Fe-IL, ethanol and water is 1 ： 1.5 ： 3 by volume ratio, and pH should be controlled at 2.0. Under such conditions, a desulfurization rate greater than 90% could be obtained. The product of sulfuric acid had inhibition effect on the wet desulfurization process. With applying this new ternary desulfurization solution, not only the catalyst Fe-IL can be recycled and reused, but also the product sulfuric acid can be separated directly from the ternary desulfurization system.

Desulfurizing absorbent for flue gas and its absorption mechanism

A new desulfurizing absorbent for flue gas, i.e., an organic physical solvent of DMSO(dimethyl sulfoxide) mixed with a relatively small amount of chemical solvent(Mn 2+ ) was studied. Compared with pure physical solvent of DMSO, the purification efficiency of the new absorbent was improved. And its absorption and reaction mechanism are discussed.

Experimental and mechanism studies on simultaneous desulfurization and denitrification from flue gas using a flue gas circulating fluidized bed

The oxidizing highly reactive absorbent was prepared from fly ash,industry lime,and an oxidizing additive M.Experiments of simultaneous desulfurization and denitrification were carried out in a flue gas circulating fluidized bed(CFB).The effects of influencing factors and calcium availability were also investigated on the removal efficiencies of desulfurization and denitrification.Removal efficiencies of 95.5%for SO2 and 64.8%for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods.The results in- dicated that more nitrogen species appeared in the spent absorbent except sulfur species.A scanning electron microscope(SEM)and an accessory X-ray energy spectrometer were used to observe micro-properties of the samples,including fly ash,oxidizing highly reactive absorbent and spent absorbent.The simultaneous removal mechanism of SO2 and NO based on this absorbent was pro- posed according to the experimental results.

Study on method and mechanism for simultaneous desulfurization and denitrification of flue gas based on the TiO_2 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 simul- taneous 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 re- moval 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.

O_(3)oxidation combined with semi-dry method for simultaneous desulfurization and denitrification of sintering/pelletizing flue gas

With the vigorous development of China's iron and steel industry and the introduction of ultra-low emission policies,the emission of pollutants such as SO_(2)and NO x has received unprecedented attention.Considering the increase of the proportion of semi-dry desulfurization technology in the desulfurization process,several semi-dry desulphurization technologies such as flue gas circulating fluidized bed(CFB),dense flow absorber(DFA)and spray drying absorption(SDA)are briefly summarized.Moreover,a method for simultaneous treatment of SO_(2)and NOx in sintering/pelletizing flue gas by O_(3)oxidation combined with semidry method is introduced.Meantime,the effects of key parameters such as O_(3)/NO molar ratio,Ca SO_(3),SO_(2),reaction temperature,Ca/(S+2 N)molar ratio,droplet size and approach to adiabatic saturation temperature(AAST)on denitrification and desulfurization are analyzed.Furthermore,the reaction mechanism of denitrification and desulfurization is further elucidated.Finally,the advantages and development prospects of the new technology are proposed.

Activity and characteristics of ＂Oxygen-enriched＂ highly reactive absorbent for simultaneous flue gas desulfurization and denitrification

An ＂Oxygen-enriched＂ highly reactive absor- bent was prepared by mixing fly ash, lime and a small quantity of KMnO4 for simultaneous desulfiarization and denitrification. Removal of SO2 and NO simultaneously was carried out using this absorbent in a flue gas circulating fluidized bed （CFB）. The highest simultaneous removal efficiency, 94.5% of SO2 and 64.2% of NO, was achieved under the optimal experiment conditions. Scanning Electron Microscope （SEM） and Accessory X-ray Energy Spectrometer （EDX） were used to observe the surface characteristics of fly ash, lime, ＂Oxygen-enriched＂ highly reactive absorbent and the spent absorbent. An ion chromatograph （IC） and chemical analysis methods were used to determine the contents of sulfate, sulfite, nitrate and nitrite in the spent absorbents, the results showed that sulfate and nitrite were the main products for desulfurization and denitrification respectively. The mechanism of removing SO2 and NO simultaneously was proposed based on the analysis results of SEM, EDX, IC and the chemical analysis methods.

焦炉烟气脱硫脱硝技术工业化应用及工艺优化分析

为解决焦炉烟气直接排放对环境造成污染以及资源浪费的问题,在对焦炉烟气成分分析以及工艺设计遵循原则分析的基础上,根据现场生产条件确定了最佳的脱硝脱硫工艺路线;基于Aspen Plus软件构建了脱硫脱硝工艺路线模型,分别对烟气流速、氨气与一氧化氮体积比、液气比以及钙硫比对脱硫脱硝效率的影响进行仿真分析,最终得出了最佳的脱硝脱硫工艺参数。

Experimental Investigation on the Performance of[APMIm][NTf_(2)]for Capturing CO_(2)from Flue Gas of the Cement Kiln Tail

Facing the global warming trend,humanity has been paying more and more attention to the Carbon Capture,Utilization and Storage.Large amounts of CO_(2)is emitted with burning fossil fuel as well as by some special industrial processes like the decomposition of calcium carbonate in a cement plant.The cement industry contributes about 7%of the total worldwide CO_(2)emissions and the CO_(2)concentration of flue gas of the cement kiln tail even exceeds 30%.Ionic liquid is considered to be an effective and potential material to capture CO_(2).In order to investigate the performance of ionic liquids for capturing CO_(2)from flue gas of the cement kiln tail,an experiment system was established and an ionic liquid,[APMIm][NTf_(2)](1-aminopropyl-3-imidazolium bis(trifluoromethylsulfonyl)imine),was tested using pure CO_(2)and simulated gas.The results showed that both physical and chemical absorption play roles while physical absorption dominates in the absorption process.Both the absorption capacity and rate decrease with raising the operating temperature.In the experiment with pure CO_(2),the absorption capacity is 0.296molCO_(2)⋅molIL−1 at 30℃ and 0.067molCO_(2)⋅molIL−1 at 70℃.Meanwhile,the ionic liquid can be regenerated for recycling without obvious changes of the absorption capacity.When the ionic liquid is used for flue gas of the cement kiln tail rather than pure CO_(2),a sharp decrease of the absorption capacity and rate was observed obviously.The absorption capacity at 30℃ dropped even to 0.038molCO_(2)⋅mol_(IL)^(−1),12.8%of that for pure CO_(2).Additionally,a natural desorption of CO_(2)from the ionic liquid was observed and affected the experimental results of the absorption capacity and the absorption-desorption rate to some extent.

硫氮液相反应研究进展

脱硫脱硝是烟气治理的一个重要发展方向 ,采用吸收剂同时吸收NO2 和SO2 ,在水溶液中会发生连续的化学反应 ,通过适当地控制反应条件 ,可以使烟气中的NOX 和SO2 经过反应生成硫酸盐、硝酸盐、铵盐有利用本价值的化学品 ,实现废物的合理利用。

一种基于事故浆液箱的顶进式搅拌机设计与加工

在传统烟气脱硫脱硝行业中,事故浆液箱由于筒高液深,经常发生搅拌轴过长易断状况,因此通常选用侧进式搅拌机进行搅拌。市场上,侧进式搅拌机价格十分昂贵,针对这一情况,文章提出了一种新型顶进式搅拌机来代替原来价格昂贵的侧进式搅拌机的方案。此新型顶进式搅拌机设计特点包括了底部增加了一个支撑;叶片选用双层组合桨,其中上层为双折叶桨叶,下层为矛形桨叶;机架采用了双支点设计;减速机采用齿轮箱形式。本研究通过理论计算、有限元分析和成本核算,确定了此新型顶进式搅拌机的可行性。类似行业中,涉及筒高液深的搅拌釜,本次新型顶进式搅拌机都可以作为参考。

硫磺回收装置尾气超低排放处理系统的设计和运行

国内某炼油厂硫磺回收装置首次应用专有气液混合器,通过钠碱湿法烟气脱硫工艺实现尾气超低排放,排放烟气中SO_2浓度为10~25mg/m^3(标准状况),脱硫率大于95%,烟气流量操作范围为0~120%,满足硫磺回收装置各种工况下的尾气超低排放要求。在国内硫磺尾气超低排放处理中首次采用气气换热提升烟气温度,有效减少了冒白烟现象,且解决了烟气管道和设备的硫露点腐蚀问题,同时节能4 950 MJ/h,节水和减排0.64t/h。

焦炉烟气脱硫脱硝系统脱硫废液处理的工艺优化

迁安中化煤化工有限责任公司焦炉烟气脱硫脱硝采用“SCR法脱硝+氨法脱硫+湿电除尘”工艺,氨法脱硫产生的废液进入硫铵工段处理,造成了饱和器阻力增加、硫铵产品质量下降、满流槽溢液等异常情况,通过采取加装压滤机过滤脱硫废液及调整饱和器操作指标等措施,解决了硫铵工段的异常问题,实现了焦炉烟气脱硫废液在硫铵工段处理的目的。

火电厂烟气脱硫脱硝尾液生物处理技术浅析

自火电行业出台相关标准后,火电厂大气污染治理工作开始面对极大的挑战。在这种情况下,须要新建或升级改造原有脱硫脱硝设施,以保证可与新标准要求相吻合。而火电厂排放烟气脱硫脱硝尾液处理逐渐成为亟待解决的问题。基于此,文章将某火电厂脱硫脱硝废水处理工程项目作为研究重点,对项目经验进行了总结与归纳,根据理论与实验研究分析,证明厌氧氨氧化工艺在脱硫脱硝尾液处理方面具有一定的可行性。

烧结机尾气脱硝(升温+SCR)消白应用实践

介绍了烧结烟气通过湿法脱硫后,利用高炉煤气加热和GGH热交换系统,采用中低温催化剂,进行选择性催化还原,实现中低温脱硝和烟气消白的应用实例。对脱硝系统及设备作了详细的介绍。

可再生型离子液体在脱硫工艺中的应用

以有机阳离子、无机阴离子为主,添加少量活化剂、抗氧化剂组成的绿色可再生型离子液体水溶液,作为脱硫吸收剂可实现烟气中的SO_(2)选择性吸附/解吸过程。本文介绍了制酸尾气和环集烟气可再生型离子液体脱硫系统的工艺原理、工艺流程、主要设备及运行情况,并针对生产运行中存在的设备腐蚀、系统堵塞、硫酸钠结晶等问题,经过多年的生产实践,通过工艺和设备的不断优化和改进,总结了采取阴离子型交换树脂为脱盐树脂、混装1 m~3弱碱性阴离子脱氯专用进口树脂、增设稀酸冷却器等设备,增加换热面积等一系列措施。该工艺绿色环保、成熟可靠、运行平稳,且副产物可回收利用,排放尾气中ρ(SO_(2))<100 mg/m~3,实现尾气SO_(2)超低排放,环保效益和经济效益显著。

有色冶炼阳极炉烟气脱硫脱硝系统改造实践

介绍了某铜冶炼公司对阳极炉烟气处理系统的改造和应用情况。通过三次改造,在对阳极炉烟气经降温、除尘、离子液脱硫处理的基础上,增加液碱喷淋系统,增设管路送部分烟气至制酸系统,以及采用离子液脱硫+低温氧化还原脱硝技术对阳极炉烟气进行脱硫脱硝处理,最终实现了烟气的洁净排放和硫资源的回收利用,同时还解决了运行过程中布袋除尘器布袋堵塞、设备腐蚀、阳极炉负压不足等系列问题,改造效果显著。

火电厂烟气脱硫脱硝尾液生物处理技术研究

针对火电厂烟气脱硫脱硝尾液处理问题,本文分析了火电厂采用的A2O和厌氧氨氧化生物处理技术,并结合实际案例探讨工艺改进问题,总结尾液生物处理经验。从理论分析和试验研究结果来看,可以采用厌氧氨氧化处理技术进行火电厂烟气尾液处理,以便减少资源浪费,取得良好的处理效果。

液相催化-生物法同时脱除烟气中SO2和NOx

对采用液相催化-生物法同时脱除烟气中SO2和NOx进行实验研究。结果表明,采用经专用菌种挂膜制作的生物膜填料塔能够实现对烟气中SO2、NOx的同时去除,在循环液中添加金属离子催化剂可以显著地提高同时脱除烟气中SO2、NOx的能力。在最佳条件下操作,生物膜填料塔对烟气中的SO2、NOx净化效率分别可达到96.8%、48.7%。