Comprehensive Solution to Flue Gas Desulfurization and Denitration of Circulating Fluidized Bed Boiler

With the advantages of high combustion efficiency, wide fuel flexibility and low concentrations of discharged pollutants, circulating fluid- ized bed （CFB） boiler has been widely used in recent years. However, in order to meet the requirement of new emission standard, it＇s necessary to add flue gas desulfurization and denitration devices. In this paper, the choice of flue gas purification processes for CFB boiler has been discussed firstly, and then the economy and rationality of the SNCR ＋ CFB-FGD ＋ COA comprehensive solution to flue gas desulfurization and denitration have been analyzed.

Improvement of High-efficiency Green Catalysts for Flue Gas Denitrification

Based on the basic principle and mechanism of flue gas denitrification,the commonly used catalysts for flue gas denitrification were introduced firstly,and then the catalytic performance,stability and reaction mechanism of catalysts in the market were analyzed.Different types of catalysts were studied to look for green catalysts with high activity,sulfur resistance,water vapor resistance and other advantages.The mechanism of denitration reaction of green catalysts was discussed,and the laws of formation,propagation and consumption of active species in the reaction process were revealed to provide theoretical basis for optimizing catalyst design and improving reaction conditions.Then the research status and problems of new catalysts for flue gas denitrification were described.Finally,the future development direction of green catalysts for flue gas denitration was discussed to improve the performance and stability of catalysts and meet the performance requirements of denitration catalysts in different industries.

生物质炭对烟气脱硝脱汞的实验研究

文章从低成本角度对烧结烟气进行脱硝脱汞研究,选用木屑在低温慢速热解条件下(室温至600℃,5℃/min)制备生物质炭,然后利用硝酸对生物质炭进行改性,最后在固定床反应器上进行脱硝和脱汞实验。通过比表面积分析和傅里叶红外光谱分析,改性生物质炭具有更大的比表面积和微孔体积,其含氧官能团和碱性原子团明显增多,两者综合作用,使得改性生物质炭的脱硝脱汞能力明显优于生物质炭的。

Properties change of activated coke for sintering flue gas purification in cyclic removal of SO_(2) and NO_(x)

The properties of activated coke(AC)for sintering flue gas purification greatly affect the efficiency of desulfurization and denitration,but they gradually change during cycles.The change in properties of coal-based AC during cycles was studied to clarify the change law and AC optimization index.The AC oxygen content rapidly increases 13.49 to 17.87 wt.%in the early cycles to form phenol,which promotes the denitration rate 55.63%to 78.20%.The denitration performance slowly increases in subsequent cycles becaof the generation of quinone AC slow oxidation.However,the oxygen-containing groups are not conducive to adsorption capacity of AC for NO.The adsorbed NO species which can be replaced SO2 is the main NO species on AC,and its amount decreases with the decrease in CC content of AC.The AC chemical loss leads to the opening of closed pores,expansion of original pores and formation of new pores,causing micropore volume to increase 0.085%to 0.152%,compressive strength to decrease 472 to 336 N,and abrasive resistance to decrease 97.87%to 94.16%during cycles.The low oxygen content and high micropore volume are favorable to the initial desulfurization performance,and the former is more decisive.After a while,the desulfurization rate is linearly positively correlated with the micropore volume regardless of the chemistry.4-h desulfurization rate increased 69.03%to 85.91%during 25 cycles due to the increasing micropore volume.The AC properties change in cycles will greatly affect the desulfurization and denitration rate in the height direction of the flue gas purification system.Selecting the coal-based AC with moderate micropore volume,easy oxidation surface and less original oxygen-containing groups facilitates the better purification efficiency at lower cost for sintering plants.

Introduction of the DeNO_x Project in Huaneng Yuhuan Power Plant

The Selective Catalytic Reduction (SCR) system for flue gas denitration applied in Yuhuan Power Plant with 4×1 000 MW units is introduced in this paper. The technology system structure, process features, basic design data and equipment layout of the SCR flue gas denitration system of original units in the plant are briefly introduced and the retrofi t method of equipments is described, which provide valuable experience for flue gas denitrification retrofit of large-size coal-fired boilers in China.

燃煤烟气脱硫脱硝脱汞技术研究现状

文章介绍了三大类燃煤烟气脱硫脱硝脱汞技术,即高能辐射、活性炭以及烟气流化床技术。对其反应原理和工艺特点进行了论述,对比了三种技术在脱硫脱硝脱汞方面的研究进展和发展潜力,最后根据各方法的优缺点及我国燃煤烟气污染现状提出了对今后烟气治理工作的建议。

氯系氧化剂在烟气脱硫脱硝脱汞中的研究进展

综述了国内外氯系氧化剂处理烟气中SO_(2)、NO和Hg^(0)的研究进展,从活性物种、脱除产物和反应途径等方面详细介绍了ClO_(2)、NaClO_(2)和NaClO的脱硫脱硝脱汞技术,分析并讨论了它们的状态和紫外光催化对脱除SO_(2)、NO和Hg^(0)的影响和作用机制,提出研发多元复合型氯系氧化体系,发展协同高效催化脱硫脱硝脱汞技术是控制烟气污染物的研究方向。

Enhanced simultaneous absorption of NO_(x) and SO_(2) in oxidation-reduction-absorption process with a compounded system based on Na_(2)SO_(3)

Oxidation of sulfite and competitive absorption existed in Na_(2)SO_(3) solution for simultaneous removal of NO_(x) and SO_(2),inhibited the long-term high-efficiency when used for practical applications.A matching strategy was developed to solve these problems.Antioxidants combination was used to retard the oxidation of antioxidant and enhance inhibition of S(IV)(tetravalent sulfur)oxidation.Hydroquinone(HQ)and sodium thiosulfate(ST)showed a positive synergistic effect on inhibition of S(IV)oxidation.When SO_(2) concentration was 500 and 2000 ppmV,the addition of 0.1 wt.%HQ and 1 wt.%ST decreased the percentage of S(IV)oxidized by oxygen by over 30%and 40%,respectively.Alkali(Na_(2)CO_(3))alleviated the competitive absorption between NO_(x) and SO_(2).Moreover,Na_(2)CO_(3) exhibited an enhancement effect on the absorption of NO_(x) and SO_(2) when coupled with anti-oxidants.While the increase of oxygen pressure accelerated the oxidation of S(IV),the anti-oxidants can retard the oxidation.The measurement of pH suggested the removal efficiency of NO_(x) highly depended on SO_(3)^(2-) concentration rather than pH.The further investigation of the mechanism suggested the match effect was related to the interaction between ST and the intermediate product of HQ.The match strategy holds a potential for application of SO_(3)^(2-) to denitration.

燃煤烟气多污染物联合脱除技术分析

介绍了燃煤烟气多污染物联合脱除技术的特点及目前存在的问题,重点阐述了联合脱除技术对燃煤烟气中硫化物、NOx和Hg的脱除原理和特点,并指出我国燃煤烟气多污染物脱除技术是未来燃煤锅炉多污染物联合控制的有效途径。

Control of nitrogen oxides emission by selective non-catalytic reduction in preheating section during iron ore pellets production

Reducing the NO_(x) emission from pelletizing process is of great importance to the green development of iron and steel industry.The flue gas temperature of preheating(PH)section during grate-kiln iron ore pelletizing process typically ranges within 850–1050℃,which meets the temperature requirements of selective non-catalytic reduction(SNCR)for NO_(x).The in-bed SNCR behavior of NO_(x) in the PH section was investigated,and the influence of relevant parameters was revealed.Results show that with the flue gas temperature rising,the denitration rate reached a peak value and then declined,where the appropriate temperature range was 950–1000℃.Increasing the NH_(3)/NO ratio(NSR)contributed to improving the denitration rate,and the appropriate NSR was 1.0.Oxygen content in the flue gas also showed an important influence on denitration rate,which reached a peak value and then dropped with the oxygen content rising.Under the condition of 18 vol.%oxygen content,the denitration reaction mainly occurred in the form of 4NO+4NH_(3)+O_(2)=4N_(2)+6H_(2)O.For restricting the competitive reaction of NH_(3) oxidation,the oxygen content in flue gas of PH section should be kept at an appropriate range.In general,the denitration rate reached about 25%in the PH section through spraying ammonia.

氧含量对嗜热膜生物反应器烟气脱硝脱汞的影响

基于嗜热生物法构建膜生物反应器实现烟气中NO和Hg^0高效处理,研究氧含量对嗜热膜生物反应器烟气脱硝脱汞性能及微生物群落结构的影响。结果表明:氧含量为2%、6%和10%时,NO去除率均稳定在80%,氧含量为17%时氧促进NO降解,NO去除率达91.0%;Hg^0去除率随氧含量的增加而升高,氧含量为17%时,Hg^0去除率可达92.0%。氧含量的增加促进氨氮的降解,且有利于硝化反应的进行。缺氧和厌氧环境有利于减少膜污染,FT-IR结果表明氧含量影响EPS中官能团含量和成分。16S rDNA结果表明氧含量10%中好氧反硝化菌占比重最高。Zobellella、Paracoccus、Bacillus、Alcaligenes、Arthrobacter、Acinetobacter、Pseudomonas均为好氧反硝化菌。