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.

Study on Flue Gas Desulfurization Process with Selective SO2 Removal by N-formylmorpholine

Absorptive separation for resource utilization by selective SO2 removal from flue gas is a potential method applicable in practice. A flue gas desulfurization process for SO2 utilization by selective absorption in a lab-scale absorption tower at atmospheric pressure using N-formylmorpholine (NFM) as the absorbent is developed to capture and concentrate the SO2 from flue gas, in which the CO2 content is several orders higher than that of SO2. The investigation of the effects of different operating conditions on the SO2 removal efficiency shows that the SO2 removal efficiency can be obviously enhanced by increasing NFM concentration, or decreasing the absorption temperature, the superficial gas velocity, the gas-liquid ratio, or the SO2 concentration in absorption solution. Under the optimum operating conditions (covering a temperature of 40 °C, a superficial gas velocity of <0.0165 m/s, a gas-liquid ratio of 200—250, a SO2 concentration in lean NFM solution of 0—10 mg/L, and a NFM concentration of 3 mol/L), the SO2 removal rate reaches over 99.5% while the absorption of CO2 is negligible. Similarly, the SO2 removal rate is as high as 99.5% obtained in consecutive absorption-desorption cycles. Desorption experiment results indicate that the absorption of sulfur dioxide is completely reversible and the release of SO2 from NFM is very easy and rapid at 104 °C. The absorption simulation result for desulfurization of flue gas vented from the industrial catalytic cracking regenerator shows that 98.0% of SO2 can be absorbed in the absorber and most of them are released in the desorber. The experimental and simulated results show that the desulfurization ability and regenerability of NFM solution is encouraging for the development of FGD process to capture the SO2 from flue gas.

Evaluation of flue gas desulfurization gypsum as a low-cost precipitant for phosphorus removal from anaerobic digestion effluent filtrate

Land application of anaerobic digestion(AD)effluent as a fertilizer is desirable for nutrient recycling,but often supplies excess phosphorus(P),which contributes to surface water eutrophication.Reducing the P content in AD effluent filtrate using calcium(Ca)treatment prior to land application is a potential strategy for improving effluent disposal and meeting the discharge standard.This study took flue gas desulphurization(FGD)gypsum,a by-product of coal-fired power plants,as a low-cost Ca source,and combined with traditional phosphorus removal agents to achieve high phosphorus removal efficiency with less chemical cost.As the results showed,FGD gypsum dosages of 20 mmol/L Ca(3.44 g/L)and 40 mmol/L Ca(6.89 g/L)removed up to 97.1%of soluble P(initially 102.8 mg/L)within 60-90 minutes.Combining FGD gypsum treatment with traditional chemical treatments using calcium hydroxide[Ca(OH)2]or ferric chloride(FeCl3)could achieve>99%P removal with reduced chemical costs.This study demonstrated that FGD gypsum is an efficient calcium-based precipitant for phosphorus removal,offering a cost-effective and sustainable approach to enhance wastewater treatment practices and meet discharge standards in wastewater management.

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.

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.

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.

燃煤锅炉超低排放改造技术实践

介绍了某公司目前*号燃煤锅炉脱硝、除尘、脱硫装置的现状及存在问题,探讨了常用的几种燃煤锅炉超低排放改造路线,比较了各自的优缺点,并结合实际选择超低排放改造的工艺路线,详细阐述了本次超低排放改造的主要内容,收集了改造后的运行情况并进行了分析。由运行数据可知,某公司*号锅炉通过超低排放改造技术实践,达到了燃煤电厂污染物排放最新指标要求。

焦化厂锅炉脱硫脱硝及烟气除尘技术探究

焦化厂锅炉在燃烧过程中会产生大量的烟气,在这些烟气中含有对环境造成污染的烟尘颗粒、含硫和含硝等物质,为避免环境污染,需要采用科学合理的除尘和脱硫脱硝技术。主要对焦化厂锅炉脱硫脱硝与烟气除尘技术进行分析与探讨,并将脱硫脱硝及烟气除尘技术应用于某焦化厂锅炉生产中。应用结果表明:该技术的应用为焦化厂锅炉污染问题的综合治理提供了技术支持,加快了焦化厂锅炉向绿色生态方向发展速度,有效减轻了焦化厂锅炉运行对生态环境造成的污染。

电力生产污染的燃煤烟气除尘脱硫处理工艺研究

电力生产燃煤产生的烟气含有大量有害气体,对人类健康和生态环境构成严重威胁。为此,研究了一种针对电力生产污染的燃煤烟气除尘脱硫处理工艺。通过人工制备的燃煤烟气样本,利用W/O/W型乳状液去除烟尘,并采用半干法烟气脱硫技术中的喷雾干燥法实现脱硫,即利用石灰与烟气的混合化学反应来去除烟气中的二氧化硫。经过验证实验,结果显示:随着除尘反应时间的延长,各样本的烟尘浓度和SO2浓度均显著下降,且除尘效率和脱硫效率均超过90.0%,表明该处理工艺在除尘脱硫方面表现出较好的性能,取得了显著效果。

燃煤焦化厂烟气脱硫吸收塔内过程优化及湿电除尘技术研究

为提高吸收塔脱硫效率,开展燃煤焦化厂烟气脱硫吸收塔内过程优化及湿电除尘技术的研究。选择某燃煤焦化厂内2×1 000 MW机组作为研究对象,建立燃煤焦化厂烟气脱硫喷淋塔几何结构模型,从反应区容积、喷淋浆液速度、喷淋负荷等多个角度分析烟气脱硫吸收塔的脱硫效率,得到结论:设置一三层、一二三层喷淋方式,且喷淋浆液速度为9 m/s,喷淋负荷在100%~160%之间,可以使燃煤焦化厂烟气吸收塔脱硫效果达到最佳。在此基础上,按照烟气预处理、电场荷电、湿式收集、连续清灰、排放与监控等步骤,进行湿电除尘技术的应用,实践证明此项技术的应用不仅能够高效去除烟气中的粉尘颗粒,达到环保标准的要求,还能够降低能耗、提高焦化厂的运行稳定性。

脱硝、脱硫、除尘环保设施处理能力改进

随着窑炉后期烟气量不断增大,增加系统阻力及用电量,且对环保设施处理效率及处理能力影响较大,通过对脱硝系统扩容、布袋过滤面积增大以及调整为反应效果较好的干法脱硫处理工艺,在改造过程中解决运行中存在的缺陷,提高了设备的处理能力,节能降耗、提质增效,对同类问题具有参考意义。

浅析制酸尾气堵塞对脱硫脱硝中制酸工艺的影响

介绍了高含尘量的烟气易造成设备积垢多,阻力增大,管道易堵塞。一旦管道堵塞,需要停机检修,造成生产停滞,成本增加。含有除尘灰的气体一旦进入制酸系统会对管道造成堵塞,对生产造成严重的影响,同时也给清理工作带来了巨大的不便。通过介绍邯钢360m^(2)烧结机的制酸工艺,在实践生产遇到的成品酸产量低的问题,通过假设并实际考察,发现制酸尾气管部分堵塞,气流不畅。这一问题在之前的检修中从未出现过,尝试各种方法后,通过增加旁通管道的方法解决,避免停机检查,减少成本支出。今后要加强对烟气杂质的控制,减少管道除尘灰的含量,有利于生产的稳定进行,设备的稳定运行。

新型湿法脱硫提效技术在火电厂超低改造实施的研究应用

按照《云南省“十四五”燃煤发电企业超低排放改造工作方案》,要求云南能投威信能源有限公司(以下简称“威信电厂”)2023年、2024年分别对#1、2机组进行超低改造,满足颗粒物、二氧化硫、氮氧化物不大于10、35、50 mg/Nm^(3)要求。经调研论证,最终确定了对现有石灰石-石膏湿法烟气脱硫系统增效改造的技术路线。本文系统提出了如何利用该路线解决石灰石-石膏湿法烟气脱硫装置脱硫效率低、除雾效率低等问题。

管式气旋除雾技术在催化烟气脱硫脱硝装置的应用分析

针对1.4 Mt/a催化烟气脱硫脱硝装置外排烟气颗粒物质量浓度设计值不达标的问题,某石化公司在原有脱硫脱硝装置基础上进行改造,增设了管式气旋除雾器,并对原湿式静电除尘器进行维修升级。实践结果表明:新增管式气旋除雾器能够有效脱除烟气中的颗粒物,满足重点地区污染物超低控制的要求。与单独运行湿式静电除尘器相比,每年约可节电109 MWh,减排颗粒物5324.4 kg。

高温除尘脱硝一体化联合钠碱法脱硫工艺在锂冶炼转型窑烟气净化中的应用

锂冶炼多以锂云母和锂辉石为原料,采用回转窑内进行火法冶炼,产生的烟气含有大量的重金属粉尘、SO_(2)和NO_(x)。以某5万t/a电池级锂盐项目回转窑烟气净化为对象,探究锂冶炼烟气的特点,选择高温尘硝一体化联合钠碱法脱硫工艺净化烟气,对工艺流程、各系统配置、核心设计参数进行详细说明,并提供了现场运行数据。烟气经过该工艺除尘脱硝脱硫后,装置出口净烟气SO_(2)浓度均低于100 mg/Nm^(3),NO_(x)浓度低于100 mg/Nm^(3),粉尘排放浓度低于10 mg/Nm^(3),各项参数达到超低排放要求,为同类锂行业火法冶炼窑尾烟气净化设计提供参考。

5.5 m捣固焦炉烟气脱硫脱硝除尘应用实践

为了满足日益趋严的环保排放要求和企业的长远发展,盛隆化工有限公司实施了5.5 m捣固焦炉烟气脱硫、脱硝、除尘技改项目。在分析盛隆公司2座5.5 m捣固焦炉烟气特点的基础上,分别对焦炉烟气脱硫、脱硝、除尘技术进行了比较和论证,最终采用干法脱硫、选择性催化还原脱硝(SCR)的工艺方案,并将干法脱硫前置,为后续低温脱硝创造了低硫、低尘的脱硝环境,使脱硝效率最优化。项目实施后不新增污染物,焦炉烟气达到山东省地方标准DB 37/2376—2019《区域性大气污染物综合排放标准》排放要求。

脱硫灰烧制陶粒装置烟气处理工艺

利用循环流化床的脱硫灰、干法或半干法脱硫工艺的副产物脱硫灰作为原料,与黏土等其他配料进入炉窑烧制成陶粒的装置,是综合利用资源化的一种新技术、新工艺。该装置排放烟气温度高、污染物具有二氧化硫、氮氧化物、灰尘浓度高等特点。本环保装置根据烟气特点,采用烟气余热回收与脱硫脱硝的联合工艺,达到烟气排放要求和余热回收节能环保目的,同时也为同类烟气治理提供了一种新的思路和参考。

钙基移动床干法脱硫除尘一体化技术处理焦炉烟气的实践应用

随着环保标准的不断提高,为进一步满足环保排放要求及特殊管控时段指标调节空间,实现脱硫脱硝双系统互为备用功能,迁安中化公司采用“钙基移动床干法脱硫除尘一体化+低温SCR脱硝”工艺对原脱硫脱硝系统进行了升级改造。介绍了改造前后的工艺流程、项目投运后的性能测试结果及运行成本分析,结果表明:改造后脱硫脱硝烟气指标能够满足超低排放要求,且运行成本降低约30%,大大降低了能源消耗及碳排放。指出了系统运行存在的不足及在后续运行中需进一步优化的改进建议。