scholarly journals Deactivation of V2O5−WO3/TiO2 DeNOx Catalyst under Commercial Conditions in Power Production Plant

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6200
Author(s):  
Maciej Zyrkowski ◽  
Monika Motak ◽  
Bogdan Samojeden ◽  
Krzysztof Szczepanek
Keyword(s):  
Power Plants ◽  
Catalyst Deactivation ◽  
Catalytic Reduction ◽  
Production Plant ◽  
Health It ◽  
High Concentration ◽  
Ammonia Slip ◽  
Different Types ◽  
The Impact ◽  
Denox Catalyst

Nitrogen dioxide is one of the most dangerous air pollutants, because its high concentration in air can be directly harmful to human health. It is also responsible for photochemical smog and acid rains. One of the most commonly used techniques to tackle this problem in large combustion plants is selective catalytic reduction (SCR). Commercial SCR installations are often equipped with a V2O5−WO3/TiO2 catalyst. In power plants which utilize a solid fuel boiler, catalysts are exposed to unfavorable conditions. In the paper, factors responsible for deactivation of such a catalyst are comprehensively reviewed where different types of deactivation mechanism, like mechanical, chemical or thermal mechanisms, are separately described. The paper presents the impact of sulfur trioxide and ammonia slip on the catalyst deactivation as well as the problem of ammonium bisulfate formation. The latter is one of the crucial factors influencing the loss of catalytic activity. The majority of issues with fast catalyst deactivation occur when the catalyst work in off-design conditions, in particular in too high or too low temperatures.

scholarly journals Numerical and Experimental Investigations on Reducing Particle Accumulation for SCR-deNOx Facilities

2019 ◽  
Vol 9 (19) ◽  
pp. 4158
Author(s):  
Zeng ◽  
Yuan ◽  
Wang
Keyword(s):  
High Speed ◽  
Power Plants ◽  
Catalyst Deactivation ◽  
Catalytic Reduction ◽  
Experimental Investigations ◽  
Duct Flow ◽  
Cfd Simulations ◽  
Particle Accumulation ◽  
Computational Fluid Dynamics Cfd ◽  
Vertical Duct

Selective catalytic reduction (SCR) is widely used to remove nitrogen oxides (NOx) in the flue gas of coal-fired power plants. The accumulation of ash particles inside the SCR-deNOx facility will increase the risk of catalyst deactivation or even damage. This paper presents the numerical and experimental investigations on the particle dispersal approach for the SCR-deNOx facility of a 1000 MW coal-fired power plant. The accumulation of different-sized particles is evaluated based on computational fluid dynamics (CFD) simulations. To prevent particles from accumulation, an optimized triangular deflector is proposed and attempts are made to find out the optimal installing position of the deflector. For the π-type SCR-deNOx facilities, the particle accumulation predominantly occurred on one side of the catalysts’ entrance, which corresponds to the inner side of the wedge-shaped turning. It is indicated that particles larger than 8.8 × 10−2 mm are responsible for the significant accumulation. The triangular deflector is proved to be an effective way to reduce particle accumulation and is found most efficient when it is installed at the high-speed area of the vertical duct. Flow model test (FMT) is carried out to validate the dispersal effect for the particle with relatively large sizes and the optimal installing position of the triangular deflector.

The Suitability of Fly Ash for Use in Concrete According to EN 450 Based on their Particle Size

2018 ◽  
Vol 276 ◽  
pp. 110-115
Author(s):  
Martin Ťažký ◽  
Martin Labaj ◽  
Rudolf Hela
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Catalytic Reduction ◽  
Raw Materials ◽  
Thermal Power ◽  
Combustion Process ◽  
Thermal Power Plants ◽  
Mechanical Parameters ◽  
Fly Ashes ◽  
The Impact

The by-products of energy industry are nowadays often affected by new limits governing the production of harmful gases discharged into the air. These stricter and stricter criteria are often met by electricity producers by changing the combustion process in thermal power plants itself. Nowadays, the SNCR (selective non-catalytic reduction) application is quite common in the combustion process in order to help reduce the nitrogen oxide emission. This article deals with the primary measures of thermal power plants, which in particular consist of a modified treatment of raw materials (coal) entering the combustion process. These primary measures then often cause the formation of fly ash with unsuitable fineness for the use in concrete according to EN 450. The paper presents the comparison of the physico-mechanical parameters of several fly ashes with a different fineness values. The primary task is to assess the impact of non-suitable granulometry in terms of EN 450 on the other physico-mechanical parameters of fly ashes sampled within the same thermal power plant. Several fly ashes produced in the Czech Republic and surrounding countries were evaluated in this way.

scholarly journals Separation of Cenospheres from Fly Ashes by Floatation Method

2010 ◽  
Vol 13 (1-2) ◽  
pp. 89 ◽  
Author(s):  
L.M. Manоcha ◽  
K.A. Ram ◽  
S.M. Manocha
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Thermal Power ◽  
Ceramic Particle ◽  
Composition Analysis ◽  
High Concentration ◽  
Fly Ashes ◽  
Power Station ◽  
Different Types ◽  
Chemical Composition Analysis

Fly-ashes are non-combustible mineral residues which are produced from coal in thermal power plants. Four different types of fly ashes were collected from different power station in Gujarat. Characterization through SEM shows that fly ash contains cenosphere i.e. gas bubble containing ceramic particle independent of their bulk density. Floatation technique was used for the separation of cenosphere from fly ash. Two solvents with extremely different densities were used for the separation of cenospheres. All methods gave approximately yield of less than 1 % cenosphere in fly ash. Color of cenospheres varied from gray to almost white and the value of density range from 0.4 – 0.8 g/cc. Further, chemical composition analysis revealed that cenospheres do not contain any high concentration of hazardous elements.

scholarly journals Research Progress on Control and Removal Technology of SO3 of Coal-fired Power Plants

2019 ◽  
Vol 118 ◽  
pp. 01036
Author(s):  
Xiuru Liu ◽  
Yiqing Sun ◽  
Fangming Xue ◽  
Jingcheng Su ◽  
jiangjiang Qu ◽  
...  
Keyword(s):  
Flue Gas ◽  
Coal Combustion ◽  
Power Plants ◽  
Catalytic Reduction ◽  
Research Progress ◽  
Combustion Mode ◽  
High Concentration ◽  
Safe Operation ◽  
Removal Technology ◽  
Coal Power Plants

SO3 is one of pollutants in flue gas of coal power plants. It mainly derived from coal combustion in boiler and selective catalytic reduction denitrification system. The content of SO3 in flue gas were influenced by the combustion mode, sulfur content in fuel, composition of denitrification catalyst and fly ash. SO3 and water vapour generated H2SO4 droplets. Sulfate secondary particles in atmosphere could cause haze, acid rain and other disastrous weather. High concentration of SO3 could cause blockage and corrosion and affect the safe operation of the units. The generation mechanism of SO3 was discussed. The latest research progress on control and removal technology of SO3 was summarized. The study in this paper provides a reference for pollutant treatment in coal-fired power plants.

Effect of Ammonium Ion Content in Fly Ash after Selective Non-Catalytic Reduction (SNCR) on Physical and Mechanical Properties of Autoclaved Aerated Concrete (AAC)

2018 ◽  
Vol 276 ◽  
pp. 148-153
Author(s):  
Matěj Lédl ◽  
Lucie Galvánková ◽  
Rostislav Drochytka
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Power Plants ◽  
Catalytic Reduction ◽  
Combustion Process ◽  
Ammonium Ion ◽  
Mixing Process ◽  
Autoclaved Aerated Concrete ◽  
Aerated Concrete ◽  
The Impact

After introducing SNCR in coal combustion process in power plants, the valuable by-product such as fly ash remains contaminated with amount of ammonia in form of NH4HSO4, (NH4)2SO4 respectively, which became undesirable in AAC technology because the toxic ammonia is released in the air during the mixing process. This paper deals with the effect of varying ammonia content in fly ash after selective non-catalytic reduction (SNCR) on the physical-mechanical properties of the fly ash based autoclaved aerated concrete (AAC) with the main focus on determination of the impact of the various content of ammonium ion in fly ash on the initial consistency of fresh slurry, the residual content of ammonium ion in hardened aerated matrix and also the impact on the bulk density, compressive strength and tobermorite formation after hydrothermal treatment. Seven batches of AAC, made out of fly ash with rising content of ammonium ion from 0 ppm to 250 ppm, were tested and based on the results obtained it was found out that ammonia is released during the mixing process entirely and doesn‘t remain in AAC after autoclaving, moreover it doesn‘t affect the properties of both fresh slurry (no apparent foaming effect noticed) and thermally treated samples of AAC. Formation of tobermorite wasn’t negatively affected.

scholarly journals The Toxic Impact of Honey Adulteration: A Review

Foods ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1538 ◽  
Author(s):  
Rafieh Fakhlaei ◽  
Jinap Selamat ◽  
Alfi Khatib ◽  
Ahmad Faizal Abdull Razis ◽  
Rashidah Sukor ◽  
...  
Keyword(s):  
Human Health ◽  
Detection Methods ◽  
Health It ◽  
Toxic Impact ◽  
Research Designs ◽  
Different Types ◽  
Valuable Product ◽  
The Impact

Honey is characterized as a natural and raw foodstuff that can be consumed not only as a sweetener but also as medicine due to its therapeutic impact on human health. It is prone to adulterants caused by humans that manipulate the quality of honey. Although honey consumption has remarkably increased in the last few years all around the world, the safety of honey is not assessed and monitored regularly. Since the number of consumers of honey adulteration have increased in recent years, their trust and interest in this valuable product has decreased. Honey adulterants are any substances that are added to the pure honey. In this regard, this paper provides a comprehensive and critical review of the different types of adulteration, common sugar adulterants and detection methods, and draws a clear perspective toward the impact of honey adulteration on human health. Adulteration increases the consumer’s blood sugar, which can cause diabetes, abdominal weight gain, and obesity, raise the level of blood lipids and can cause high blood pressure. The most common organ affected by honey adulterants is the liver followed by the kidney, heart, and brain, as shown in several in vivo research designs.

scholarly journals Load Nowcasting: Predicting Actuals with Limited Data

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1443
Author(s):  
Florian Ziel
Keyword(s):  
Power Plants ◽  
Model Structure ◽  
Limited Data ◽  
Recent Past ◽  
Ridge Estimator ◽  
Accuracy Improvement ◽  
Energy Forecasting ◽  
Different Types ◽  
The Impact ◽  
Generation Unit

We introduce the problem of load nowcasting to the energy forecasting literature. The recent load of the objective area is predicted based on limited available metering data within this area. Thus, slightly different from load forecasting, we are predicting the recent past using limited available metering data from the supply side of the system. Next, to an industry benchmark model, we introduce multiple high-dimensional models for providing more accurate predictions. They evaluate metered interconnector and generation unit data of different types like wind and solar power, storages, and nuclear and fossil power plants. Additionally, we augment the model by seasonal and autoregressive components to improve the nowcasting performance. We consider multiple estimation techniques based on the lassoand ridge and study the impact of the choice of the training/calibration period. The methodology is applied to a European TSO dataset from 2014 to 2019. The overall results show that in comparison to the industry benchmark, an accuracy improvement in terms of MAE and RMSE of about 60% is achieved. The best model is based on the ridge estimator and uses a specific non-standard shrinkage target. Due to the linear model structure, we can easily interpret the model output.

An implementation model for automated construction materials tracking and locating

2010 ◽  
Vol 37 (4) ◽  
pp. 588-599 ◽  
Author(s):  
Hassan Nasir ◽  
Carl T. Haas ◽  
Duncan A. Young ◽  
Saiedeh Nawabzadi Razavi ◽  
Carlos Caldas ◽  
...  
Keyword(s):  
Construction Projects ◽  
Power Plants ◽  
Emerging Technologies ◽  
Construction Materials ◽  
Materials Management ◽  
Implementation Model ◽  
Different Types ◽  
Industrial Projects ◽  
The Right ◽  
The Impact

Good materials management on large construction projects is critical for maximizing productivity and project performance. When key materials are temporarily lost, whole crews may be left idle and the project may be delayed. When key materials are completely lost, the impact can be enormous. In fact, one of the major problems in managing construction materials and equipment is tracking them in the supply chain and knowing their location on large job sites. Fortunately, location can now be automatically estimated within metres using emerging technologies. This paper proposes a general implementation model for automated construction materials tracking and locating on large industrial projects, such as refineries and power plants. It includes a methodology for determining what type of technology should be used for different types of projects and construction materials. It is based on an analysis of the capabilities of emerging technologies and on experience gained from implementing automated materials tracking prototypes on two large industrial projects. It is concluded that these technologies can produce substantial net benefits, if implemented properly on the right projects using the model described here.

Quota Women Are Threatening to Men

2017 ◽  
Vol 76 (3) ◽  
pp. 107-116 ◽  
Author(s):  
Klea Faniko ◽  
Till Burckhardt ◽  
Oriane Sarrasin ◽  
Fabio Lorenzi-Cioldi ◽  
Siri Øyslebø Sørensen ◽  
...  
Keyword(s):  
Decision Making ◽  
Organizational Performance ◽  
Gender Stereotypes ◽  
Perceived Threat ◽  
Preferential Treatment ◽  
Public Sector Employees ◽  
Different Types ◽  
Low Levels ◽  
Women In Decision Making ◽  
The Impact

Abstract. Two studies carried out among Albanian public-sector employees examined the impact of different types of affirmative action policies (AAPs) on (counter)stereotypical perceptions of women in decision-making positions. Study 1 (N = 178) revealed that participants – especially women – perceived women in decision-making positions as more masculine (i.e., agentic) than feminine (i.e., communal). Study 2 (N = 239) showed that different types of AA had different effects on the attribution of gender stereotypes to AAP beneficiaries: Women benefiting from a quota policy were perceived as being more communal than agentic, while those benefiting from weak preferential treatment were perceived as being more agentic than communal. Furthermore, we examined how the belief that AAPs threaten men’s access to decision-making positions influenced the attribution of these traits to AAP beneficiaries. The results showed that men who reported high levels of perceived threat, as compared to men who reported low levels of perceived threat, attributed more communal than agentic traits to the beneficiaries of quotas. These findings suggest that AAPs may have created a backlash against its beneficiaries by emphasizing gender-stereotypical or counterstereotypical traits. Thus, the framing of AAPs, for instance, as a matter of enhancing organizational performance, in the process of policy making and implementation, may be a crucial tool to countering potential backlash.

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