Dew Point of the Flue Gas of Boilers Co-Firing Biomass with Coal

2013 ◽  
Vol 34 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Szymon Ciukaj ◽  
Marek Pronobis
Keyword(s):  
Regression Analysis ◽  
Moisture Content ◽  
Flue Gas ◽  
Large Scale ◽  
Fuel Mixture ◽  
Dew Point ◽  
Outlet Temperature ◽  
Utility Boilers ◽  
Boiler Efficiency ◽  
The Impact

Abstract The paper deals with the impact of co-firing biomass with coal in boilers on the dew point of the flue gas. Co-firing of biomass may have twofold implications on corrosion and fouling, which are the processes that determine the lowest acceptable flue gas outlet temperature and as a result, boiler efficiency. Both phenomena may be reduced by co-firing of usually low sulphur biomasses or enhanced due to increased moisture content of biomass leading to increased water dew point. The present study concerns the problem of low-temperature corrosion in utility boilers. The paper gives (in the form of diagrams and equations) a relationship between water dew point and moisture content of fuel mixture when co-firing coal and various biomasses. The regression analysis shows that despite significant differences in the characteristics of coals and these of additional fuels, which are planned for co-firing in large-scale power boilers, the water dew point can be described by a function given with the accuracy, which shall be satisfactory for engineering purposes. The discussion of the properties of biofuels indicates that the acid dew point surplus over the water dew point (Δtr = tr - twr) is not likely to exceed 10 K when co-firing biomass. The concluding remarks give recommendations for the appropriate operation of boilers in order to reduce risks associated with biomass co-combustion.

The Impact of Extraversion and Sensation Seeking on Tourist Role

2015 ◽  
Vol 43 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Cheng-Yu Li ◽  
Shiao-Yuan Lu ◽  
Bi-Kun Tsai ◽  
Keh-Yuan Yu
Keyword(s):  
Logistic Regression ◽  
Regression Analysis ◽  
Logistic Regression Analysis ◽  
Sensation Seeking ◽  
Large Scale ◽  
Personality Variables ◽  
Tourism Marketing ◽  
Large Scale Survey ◽  
And Behaviors ◽  
The Impact

In recent years, personality variables, such as extraversion and sensation seeking, have been used to investigate tourist preferences and behaviors. For this study, we classified tourist roles into three types: the familiarized mass tourist, the organized mass tourist, and the independent tourist. We investigated the impact of extraversion and sensation seeking on tourist roles in a large-scale survey of Taiwanese citizens (N = 1,249) aged 20 years and older. Using logistic regression analysis, the results indicated that sensation seeking was a significant predictor of tourist role, but extraversion was not. Compared to familiarized mass tourists, people who are sensation-seeking are more likely to become independent tourists rather than organized mass tourists. We provide suggestions for tourism marketing.

scholarly journals Ethylene Yield from Pyrolysis Cracking in Olefin Plant Utilizing Regression Analysis

2021 ◽  
Vol 287 ◽  
pp. 03004
Author(s):  
Mohamad Hafizi Zakria ◽  
Mohd Ghazali Mohd Nawawi ◽  
Mohd Rizal Abdul Rahman
Keyword(s):  
Regression Analysis ◽  
Water Flow ◽  
Large Scale ◽  
Nox Emission ◽  
Feed Water ◽  
Yield Model ◽  
Liquid Feed ◽  
The Impact ◽  
Steam Drum ◽  
Boiler Feed Water

Ethylene yield is significant in showing the performance of the steam cracker furnace in the olefin plant. This study was conducted in the actual large-scale olefin plant to see the impact of various variables towards the ethylene yield. The analysis was conducted utilizing Regression Analysis in Minitab Software Version 18 to develop a reliable ethylene yield model. The model concluded that ethylene yield in the studied plant was contributed by the factor of -0.000901, 0.02649, -0.282, 0.16, -0.0834, 0.1268, and 0.0057 of Hearth Burner Flow, Integral Burner Flow, Steam Drum Pressure, Super High-Pressure Steam (SHP) Boiler Feed Water Flow, SHP Flow, Naphtha Feed Flow, and Stack NOx Emission respectively. The Response Optimizer tool also showed that the ethylene yield from naphtha liquid feed utilizing pyrolysis cracking can be maximized at 32.55% with control setting at 9,476.41 kg/hr of Hearth Burner Flow, 608.56 kg/hr of Integral Burner Flow, 112.93 Barg of Steam Drum Pressure, 109.11 t/hr of SHP Boiler Feed Water Flow, 86.42 t/hr of SHP Flow, 63.49 t/hr of Naphtha Feed Flow and 126.23 mg/m3 of Stack NOx Emission.

scholarly journals The Impact of Secondary Phyllosilicate Minerals on the Engineering Properties of Various Igneous Aggregates from Greece

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 329 ◽  
Author(s):  
Petros Petrounias ◽  
Panagiota Giannakopoulou ◽  
Aikaterini Rogkala ◽  
Paraskevi Lampropoulou ◽  
Eleni Koutsopoulou ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Los Angeles ◽  
Moisture Content ◽  
Total Porosity ◽  
Physicomechanical Properties ◽  
Engineering Properties ◽  
Petrographic Analysis ◽  
Rock Samples ◽  
Los Angeles Abrasion ◽  
The Impact

This paper investigates the effect of alteration on the physicomechanical properties of igneous rocks used as aggregates, from various areas from Greece. The studied lithologies include serpentinized dunites, serpentinized harzburgites, serpentinized lherzolites, metamorphic gabbros, diabases, dacites and andesites. Quantitative petrographic analysis shows that the tested samples display various percentages of secondary phyllosilicate minerals. Mineral quantification of the studied rock samples was performed by using the Rietveld method on X-ray diffraction patterns. The samples were also tested to assign moisture content (w (%)), total porosity (nt (%)), uniaxial compressive strength (UCS (MPa)) and Los Angeles abrasion test (LA (%)). The influence of secondary phyllosilicate minerals on the physicomechanical behavior of the tested samples was determined using regression analysis and their derived equations. Regression analysis shows a positive relationship between the percentage of the phyllosilicate minerals of the rocks and the moisture content as well as with the total porosity values. In mafic and ultramafic rock samples, the relationships between the secondary phyllosilicate minerals and their physicomechanical properties have shown that the total amount of the secondary phyllosilicate minerals results negatively on their physicomechanical properties. On the other hand, the low percentage of phyllosilicate minerals in volcanic rocks can’t be able to define their engineering properties.

Reduction of Pollutant Emissions From Industrial Boilers by Combustion Modification

1977 ◽  
Vol 99 (3) ◽  
pp. 320-328 ◽  
Author(s):  
G. A. Cato ◽  
R. E. Hall ◽  
L. J. Muzio
Keyword(s):  
Flue Gas ◽  
Pollutant Emissions ◽  
Particulate Emissions ◽  
Test Program ◽  
Utility Boilers ◽  
Boiler Efficiency ◽  
Before And After ◽  
Particulate Size ◽  
Oil And Natural Gas ◽  
Industrial Boilers

The use of combustion modification has enabled many utility boilers to meet the emission standards for NOx. Its usefulness in reducing NOx emissions from industrial boilers (ranging from 11 GJ/hr to 528 GJ/hr) has been investigated during a recently completed field test program. The gaseous and particulate emissions from coal, oil, and natural-gas fuels were measured both before and after the combustion modification. Data were taken on particulate size as well as concentration. The principal combustion modification methods that were investigated included reduced excess combustion air, staged combustion air, recirculated flue gas, tuned burners, and reset burner registers. Staging was implemented by the use of overfire air ports or by turning off the fuel to some burners and increasing the fuel to others, thus creating zones of fuel-rich combustion. All of the combustion modification methods were effective to varying degrees in reducing the nitrogen oxides emissions, and reductions of as much as 50 percent were obtained with several of the modifications. In most instances the boiler efficiency was not degraded, although the particulate emissions increased by up to 50 percent in some cases. There was no substantive effect on the other pollutant emissions that were measured.

scholarly journals Status and development for detection and control of ammonium bisulfate as a by-product of SCR denitrification

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kunling Jiao ◽  
Xiangyang Chen ◽  
Xuan Bie ◽  
Daokuan Liu ◽  
Mingjie Qiu ◽  
...  
Keyword(s):  
Flue Gas ◽  
Negative Impact ◽  
Dew Point ◽  
Detection Methods ◽  
Nox Removal ◽  
Air Preheater ◽  
Catalyst Life ◽  
Ammonium Bisulfate ◽  
The Impact ◽  
Ammonia Injection

AbstractWhen denitrification technology using NH3 or urea as the reducing agent is applied to remove NOx from the flue gas, ammonium bisulfate (ABS) by-product will also be generated in the flue gas. ABS has an impact on catalyst life span, denitrification efficiency etc., air preheater and its downstream thermal equipment also have a significant negative impact due to its plugging and corrosion. The requirement for NOx removal efficiency is improved by ultra-low emissions in China. However, wide-load denitrification makes the flue gas composition and temperature changing more complicated. Increasing ammonia injection can improve the NOx removal effect, but too much ammonia injection will lead to the formation of ABS and the increase of deposition risk, the contradiction between these two aspects is amplified by ultra-low emissions and wide-load denitrification in many plants. Coordinating NOx control and reducing the impact of ABS on equipment are issues that the industry needs to solve urgently. In recent years, extensive research on ABS had been carried out deeply, consequently, there has been a relatively in-deepth knowledge foundation for ABS formation, formation temperature, deposition temperature, dew point temperature, decomposition behavior, etc., but the existing researches are insufficient to support the problem of ABS under full load denitrification completely resolved. Therefore, some analysis and detection methods related to ABS are reviewed in this paper, and the impact of ABS on SCR, air preheater and other equipment and the existing research results on reducing the impact of ABS are summarized also. It is hoped that this review will provide a reference for the industry to solve the problems of ABS that hinder wide-load denitrification and affect ultra-low emissions.

Discuss on Post Combustion Characteristics of the 116MW Circulating Fluidized Bed Hot Water Boiler

2013 ◽  
Vol 291-294 ◽  
pp. 1714-1718
Author(s):  
Guo Li Qi ◽  
Jian Guan ◽  
Hao Leng
Keyword(s):  
Fluidized Bed ◽  
Temperature Rise ◽  
Flue Gas ◽  
Circulating Fluidized Bed ◽  
Performance Testing ◽  
Hot Water ◽  
Outlet Temperature ◽  
Boiler Efficiency ◽  
Boiler Operation ◽  
Boiler Design

116MW circulating fluidized bed hot water boiler performance testing was carried out that found that burning high volatile lignite had post combustion phenomenon of separator yet. The phenomenon of post-combustion research results show that flue gas outlet temperature rise of the separation can be significantly reduced by adjusting the twelve wind ratio; Increasing coal-fired granularity which was able to reduce the separator post combustion phenomenon; Moderate post combustion of separation was able to improve boiler efficiency and reduce N2O. These results can provide guidance for improving boiler operation technology and improving the boiler design standard.

scholarly journals Modelling of dew point operating conditions in a rotary regenerative air heater

2021 ◽  
Vol 347 ◽  
pp. 00020
Author(s):  
Warren Brandt ◽  
Walter Schmitz ◽  
Thomas John Sheer ◽  
Mike Lander
Keyword(s):  
Flue Gas ◽  
Research Problem ◽  
Operating Conditions ◽  
Dew Point ◽  
Steel Matrix ◽  
Premature Failure ◽  
Air Heater ◽  
Erosion Rates ◽  
Boiler Efficiency ◽  
Production Losses

Dew point related fouling of regenerative rotary air heaters contributes to efficiency reduction of coal-fired boilers. This fouling commonly causes high pressure differences over the air heater steel matrix, along with elevated leakage rates, resulting in increased loading of draught group fans. These increases also conduce to excessive erosion rates, introducing premature failure of element packs and draught group components. The research problem aimed to develop, and validate, a modelling tool to predict the onset of dew point related fouling for regenerative rotary air heaters (VBA RAH model). A modelling tool equip system engineers with the knowledge to enhance operating conditions and maintenance strategies, to prevent the onset of dew point related fouling. The results yielded that the cold end of the air heater packs experience sulphuric acid dew point related fouling for at 670MW(90% MCR), at 544MW(80% MCR) and at 468MW(68% MCR) of the exposure time to the flue gas stream. Different operating and design change configurations were simulated to find potential solutions to minimize dew point related fouling and improving boiler efficiency. The tool provides a platform for identifying methods to reduce maintenance costs and production losses, which will contribute to improved and sustainable operating of coal fired power generation plants.

scholarly journals The Impact of Secondary Phyllosilicate Minerals on the Engineering Properties of Various Igneous Aggregates from Greece

2018 ◽  
Author(s):  
Petros Petrounias ◽  
Panagiota P. Giannakopoulou ◽  
Aikaterini Rogkala ◽  
Paraskevi Lampropoulou ◽  
Eleni Koutsopoulou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Regression Analysis ◽  
Los Angeles ◽  
Moisture Content ◽  
Rietveld Method ◽  
Total Porosity ◽  
Engineering Properties ◽  
Petrographic Analysis ◽  
Los Angeles Abrasion ◽  
The Impact

This paper investigates the effect of alteration on the physicomechanical properties of igneous rocks from various areas from Greece used as aggregates. The studied lithologies include dunites, harzburgites, lherzolites, gabbros, diabases, dacites and andesites. Quantitative petrographic analysis shows that the tested samples display various percentages of secondary phyllosilicate minerals. Mineral quantification of studied rock samples was performed by using a Rietveld method on X-Ray diffraction patterns of the studied aggregates. The aggregates are also tested to assign moisture content [w (%)], total porosity [nt (%)], uniaxial compressive strength [UCS (MPa)] and Los Angeles abrasion test [LA (%)]. The influence of secondary phyllosilicate minerals on physicomechanical behavior of tested samples determined using regression analysis and their derived equations. Regression analysis shows positive relationship between the percentage of phyllosilicate minerals of rocks and moisture content as well as with the total porosity values. The relationships between phyllosilicate minerals in the ultramafic and mafic samples and their mechanical properties show that the total rates of phyllosilicate mineral products result negatively in their mechanical properties, while the low percentage of phyllosilicate minerals in volcanic rocks are not able to define set of their engineering parameters.

The Impact of Alternative Models of Leasing on Financing Investments

2013 ◽  
pp. 82-97
Author(s):  
V. Gazman
Keyword(s):  
Regression Analysis ◽  
Large Scale ◽  
Foreign Capital ◽  
Financial Leverage ◽  
Alternative Models ◽  
Methodological Aspects ◽  
The Impact

For the modernization of the economy some specific financial technologies can be useful. They have hardly been used in Russia, but can greatly increase the share of leasing in investment and attract domestic and foreign capital in new projects, including infrastructure, extend financial leverage of loans. This article explores the benefits of innovative models of leasing, theoretical and methodological aspects of their formation, identifies the criteria for using the proposed models, and conducts regression analysis of factors that influence the pricing of large-scale leasing projects. These models expand the line of investment products, promote competition between sources of funding of leasing.

Modeling of Superheater Operation in a Steam Boiler

2014 ◽  
Author(s):  
Marcin Trojan ◽  
Dawid Taler ◽  
Jan Taler ◽  
Piotr Dzierwa
Keyword(s):  
Flue Gas ◽  
Tube Wall ◽  
Numerical Technique ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Steam Boiler ◽  
Steam Temperature ◽  
Additional Increase ◽  
Internal Surfaces ◽  
The Impact

A numerical method for modeling actual steam superheaters is presented. The finite volume method was used to determine flue gas, tube wall and steam temperature. The numerical technique presented in the paper can especially be used for modeling boiler superheaters with a complex tube arrangement when detail information on the tube wall temperature distribution is needed. The method of modeling the superheater can be used both in the design, performance as well as in upgrading the superheaters. If the steam temperature at the outlet of the superheater is too low or too high, the designed outlet temperature can be achieved by changing a flow arrangement of the superheater. For example, the impact of the change of the counter to parallel flow or to mixed flow can be easily assessed. The presented method of modeling is a useful tool in analyzing the impact of the internal scales or outer ash fouling on the superheater operating conditions. Both ash deposits at the external and scales at the internal surfaces of the tubes contribute to the reduction of the steam temperature at the outlet of the superheater. Furthermore, scale deposits on the inner surface of the tubes cause a significant temperature rise and may lead to the tube damage. The higher temperature of the flue gas over a part of parallel superheater tubes increases the steam temperature and decreases steam mass flow rate through the tubes with excessive heating. This results in an additional increase in the steam temperature at the outlet of the superheater.

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