Effect of selective catalytic reduction (SCR) on fine particle emission from two coal-fired power plants in China

Li, Zhen; Jiang, Jingkun; Ma, Zizhen; Wang, Yafei; Duan, Lei

doi:10.1016/j.atmosenv.2015.08.046

Cited by 75 publications

(32 citation statements)

References 37 publications

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“…It is reported that only about 0.5–1.5% of the sulfur is oxidized to SO 3 . However, when a selective catalytic reduction (SCR) system has been used in a power plant for NOx abatement, some SO 2 will also be converted into SO 3 with the conversion rate being about 0.25 to 1.25% . After passing through the air pre‐heater (APH), virtually all SO 3 is converted into gaseous H 2 SO 4 by reacting with water vapor at a temperature above its acid dew point .…”

Section: Introductionmentioning

confidence: 99%

Removal of sulfuric acid aerosols in desulfurized flue gas by adding moist air

Hao

Pan

Hong³

et al. 2016

J. Chem. Technol. Biotechnol.

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BACKGROUND: The reduction of sulfuric acid aerosol emissions in coal fired power plant is of great importance. Based on the classical theory of heterogeneous vapor condensation, a novel engineering process was proposed to increase the efficiency of removal of sulfuric acid aerosols by adding moist air in the condensational growth chamber (CGC), following the desulfurization scrubber. RESULTS:The theoretical analysis showed that this novel process was feasible. The experimental results indicated that the efficiency of removal of sulfuric acid aerosols was mainly influenced by the amount of moist air added and the humiture of desulfurized flue gas and moist air. Higher humiture of desulfurized flue gas could promote removal efficiency, whereas higher temperature of moist air was unfavorable. However, the influence of the relative humidity of moist air was not obvious. Moreover, increasing the mixture ratio was also beneficial for the improvement of removal performance in the range below 10:20. CONCLUSION: The process proposed was feasible for industrial application. The efficiency of removal of sulfuric acid aerosols was enhanced to 30-50% by this novel process.

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Section: Introductionmentioning

confidence: 99%

Removal of sulfuric acid aerosols in desulfurized flue gas by adding moist air

Hao

Pan

Hong³

et al. 2016

J. Chem. Technol. Biotechnol.

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“…Water vapor and SO 3 in the flue gas react to form gaseous H 2 SO 4 . In addition, we know from Li et al [42] that the ammonia (NH 3 ) used in an SCR can react with H 2 O and SO 3 to generate ammonium sulphate ((NH 4 ) 2 SO 4 ) and/or bisulphate (NH 4 HSO 4 ). The rapid drop in temperature in the WFGD leads to the supersaturation of all SO 3 molecules and homogeneous liquid and/or heterogeneous solid–liquid aerosols are formed by nucleation mechanisms [43].…”

Section: Resultsmentioning

confidence: 99%

“…Comparing the flue gas cleaning steps of both power plants and their influence on aerosol formation results in a reasonable explanation for the membrane damage in Karlsruhe compared with the stable SILM operation in Niederaussem (see Table 8)—the presence of larger quantities of SO 3 aerosols, such as sulfuric acid and especially sticky ammonium sulphate and/or bisulphate, in the EnBW power plant (block 8) in Karlsruhe. In particular, the formation of sticky ammonium sulphate and bisulphate aerosols due to the presence of ammonia as a reducing agent in an SCR [42] is possible at the EnBW power plant in Karlsruhe. In addition, it is likely that more gaseous H 2 SO 4 formed in Karlsruhe since the additional oxidation of SO 2 to SO 3 may occur in an SCR [42].…”

Section: Resultsmentioning

confidence: 99%

“…In particular, the formation of sticky ammonium sulphate and bisulphate aerosols due to the presence of ammonia as a reducing agent in an SCR [42] is possible at the EnBW power plant in Karlsruhe. In addition, it is likely that more gaseous H 2 SO 4 formed in Karlsruhe since the additional oxidation of SO 2 to SO 3 may occur in an SCR [42]. Additional SO 3 may have also formed in the ESP [38], which applies to both power plants.…”

Section: Resultsmentioning

confidence: 99%

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Separation of Carbon Dioxide from Real Power Plant Flue Gases by Gas Permeation Using a Supported Ionic Liquid Membrane: An Investigation of Membrane Stability

et al. 2019

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The separation of carbon dioxide from coal-fired power plant flue gases using a CO2/N2-selective supported ionic liquid membrane (SILM) was investigated and the performance and stability of the membrane during operation are reported. The membrane is composed of a polyacrylonitrile (PAN) ultrafiltration membrane as a support and a selective layer of an ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM Tf2N). The feasibility of large-scale SILM production was demonstrated by the formation of a square-meter-scale membrane and preparation of a membrane module. A flat-sheet envelope-type SILM module containing 0.67 m2 of the membrane was assembled. Prior to real flue gas operation, the separation behaviour of the membrane was investigated with single gases. The stability of the SILM during the test stand and pilot plant operation using real power plant flue gases is reported. The volume fraction of carbon dioxide in the flue gas was raised from approx. 14 vol. % (feed) to 40 vol. % (permeate). However, issues concerning the membrane stability were found when SO3 aerosols in large quantities were present in the flue gas.

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“…Nevertheless, the introduction of an amine scrubber for CO 2 capture raises another potential issue: The treated exhaust gas from a power plant may contain a large number of fine particles, which can act as condensation sites and carry a large amount of amine in the aerosol phase out of the CO 2 scrubber, resulting in increased amine losses and causing environmental concerns. A recent assessment of the NO x control selective catalytic reduction (SCR) (Li et al 2015b) indicated that the SCR treatment tremendously increased both the number and mass concentration of PM 2.5 emitted by a coal-fired power plant. The presence of fine particles in the flue gas could be attributed to a "penetration window," which is the size range of particles that pass through the ESP, around 100 nm for traditional ESPs (Strand et al 2002;Ylätalo and Hautanen 1998;Zhuang et al 2000).…”

Section: Introductionmentioning

confidence: 99%

Investigation of aerosol and gas emissions from a coal-fired power plant under various operating conditions

Biswas

2018

Journal of the Air & Waste Management Association

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The concentrations of fine particles and selected gas pollutants in the flue gas entering the stack were measured under several common operation modes in an operating coal power plant producing electricity. Particle size distributions in a diameter range from 10 nm to 20 μm were measured by a scanning mobility particle sizer (SMPS), and the flue gas temperature and concentrations of CO and SO were monitored by a continuous emission monitoring system (CEMS). During the test campaign, five plant operating modes were studied: soot blowing, bypass of flue-gas desulfurization (FGD), reheat burner operating at 0% (turned off), 27%, and 42% (normal condition) of its full capacity. For wet and dry aerosols, the measured mode sizes were both around 40 nm, but remarkable differences were observed in the number concentrations (#/cm, count per square centimeter). A prototype photoionizer enhanced electrostatic precipitator (ESP) showed improved removal efficiency of wet particles at voltages above +11.0 kV. Soot blowing and FGD bypass both increased the total particle number concentration in the flue gas. The temperature was slightly increased by the FGD bypass mode and varied significantly as the rating of reheat burner changed. The variations of CO and SO emissions showed correlations with the trend of total particle number concentration possibly due to the transitions between gas and particle phases. The results are useful in developing coal-fired power plant operation strategies to control fine particle emissions and developing amine-based CO capture technologies without operating and environmental concerns associated with volatile amine emissions. Implications: The measurement of the fine particle size distributions in the exhaust gas under several common operating conditions of a coal-fired power plant revealed different response relations between aerosol number concentration and the operating condition. A photo-ionizer enhanced ESP was demonstrated to capture fine particles with higher efficiency compared to conventional ESPs, and the removal efficiency increased with the applied voltage. The characteristic information of aerosols and main gaseous pollutants in the exhaust gas is extremely important for developing and deploying CO scrubbers, whose amine emissions and operating effectiveness depends greatly on the upstream concentrations of fine particles, SO, from the power plant.

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Effect of selective catalytic reduction (SCR) on fine particle emission from two coal-fired power plants in China

Cited by 75 publications

References 37 publications

Removal of sulfuric acid aerosols in desulfurized flue gas by adding moist air

Removal of sulfuric acid aerosols in desulfurized flue gas by adding moist air

Separation of Carbon Dioxide from Real Power Plant Flue Gases by Gas Permeation Using a Supported Ionic Liquid Membrane: An Investigation of Membrane Stability

Investigation of aerosol and gas emissions from a coal-fired power plant under various operating conditions

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