Study on the technology of SCR flue gas temperature adjustment during low load in coal-fired boilers

During the operation of a 300MW subcritical boiler of a power plant, there is a low temperature of the SCR inlet flue gas under medium and low load conditions. In order to effectively solve the problem of low SCR inlet temperature under low load conditions, and improve the adaptability of the coal type. Three kinds of wide load denitration technology reform schemes are proposed. With the boiler thermal system simulation software BESS, the thermal calculations of the three transformation schemes were carried out. The results show that: the Scheme C is the optimal solution. After the transformation, the temperature of the SCR inlet flue gas increased by 21°C under the ultra-low load condition, and the exhaust gas temperature increased by about 7°C. At the same time, the possible impacts of the reform of the Scheme C and the key issues that need to be paid attention to during the transformation process are evaluated and discussed.

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Low-Cost Organic Adsorbents for Elemental Mercury Removal from Lignite Flue Gas

Energies ◽

10.3390/en14082174 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2174

Author(s):

Marta Marczak-Grzesik ◽

Stanisław Budzyń ◽

Barbara Tora ◽

Szymon Szufa ◽

Krzysztof Kogut ◽

...

Keyword(s):

Flue Gas ◽

Low Cost ◽

Elemental Mercury ◽

Mercury Content ◽

Flue Gases ◽

Mercury Removal ◽

Gas Purification ◽

Gas Temperature ◽

Corn Straw ◽

Flue Gas Purification

The research presented by the authors in this paper focused on understanding the behavior of mercury during coal combustion and flue gas purification operations. The goal was to determine the flue gas temperature on the mercury emissions limits for the combustion of lignites in the energy sector. The authors examined the process of sorption of mercury from flue gases using fine-grained organic materials. The main objectives of this study were to recommend a low-cost organic adsorbent such as coke dust (CD), corn straw char (CS-400), brominated corn straw char (CS-400-Br), rubber char (RC-600) or granulated rubber char (GRC-600) to efficiently substitute expensive dust-sized activated carbon. The study covered combustion of lignite from a Polish field. The experiment was conducted at temperatures reflecting conditions inside a flue gas purification installation. One of the tested sorbents—tire-derived rubber char that was obtained by pyrolysis—exhibited good potential for Hg0 into Hg2+ oxidation, resulting in enhanced mercury removal from the flue. The char characterization increased elevated bromine content (mercury oxidizing agent) in comparison to the other selected adsorbents. This paper presents the results of laboratory tests of mercury sorption from the flue gases at temperatures of 95, 125, 155 and 185 °C. The average mercury content in Polish lignite was 465 μg·kg−1. The concentration of mercury in flue gases emitted into the atmosphere was 17.8 µg·m−3. The study analyzed five low-cost sorbents with the average achieved efficiency of mercury removal from 18.3% to 96.1% for lignite combustion depending on the flue gas temperature.

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The Energy-Saving Optimization of the Organic Heat Transfer Material Heater

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.455-456.284 ◽

2012 ◽

Vol 455-456 ◽

pp. 284-288

Author(s):

Wei Li Gu ◽

Jian Xiang Liu

Keyword(s):

Heat Transfer ◽

Energy Saving ◽

Flue Gas ◽

Theoretical Basis ◽

Operation Management ◽

Exergy Loss ◽

Irreversible Processes ◽

Design Parameters ◽

Gas Temperature

this paper studies the typical irreversible processes such as combustion and heat transfer with temperature difference based on the theory of thermodynamics, analyzes the influencing factors on exergy loss in irreversible processes, on the basis of this analysis, proposes the energy-saving optimization measures on design and operation management of the organic heat transfer material heater, and specially points out that in the design process, objective function can be constructed with the exergy loss as evaluation index to determine the outlet flue gas temperature of furnace and the flue gas temperature, and provides theoretical basis for the determination of design parameters.

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Numerical simulation and field test study of desulfurization wastewater evaporation treatment through flue gas

Water Science & Technology ◽

10.2166/wst.2014.359 ◽

2014 ◽

Vol 70 (7) ◽

pp. 1285-1291 ◽

Cited By ~ 12

Author(s):

Jia-jia Deng ◽

Liang-ming Pan ◽

De-qi Chen ◽

Yu-quan Dong ◽

Cheng-mu Wang ◽

...

Keyword(s):

Field Test ◽

Flue Gas ◽

Cfd Simulation ◽

Electrostatic Precipitator ◽

Negative Impact ◽

Positive Impact ◽

Field Tests ◽

Gas Temperature ◽

Simulation Results ◽

Desulfurization Wastewater

Aimed at cost saving and pollution reduction, a novel desulfurization wastewater evaporation treatment system (DWETS) for handling wet flue gas desulfurization (WFGD) wastewater of a coal-fired power plant was studied. The system's advantages include simple process, and less investment and space. The feasibility of this system has been proven and the appropriate position and number of nozzles, the spray droplet size and flue gas temperature limitation have been obtained by computational fluid dynamics (CFD) simulation. The simulation results show that a longer duct, smaller diameter and higher flue gas temperature could help to increase the evaporation rate. The optimal DWETS design of Shangdu plant is 100 μm droplet sprayed by two nozzles located at the long duct when the flue gas temperature is 130 °C. Field tests were carried out based on the simulation results. The effects of running DWETS on the downstream devices have been studied. The results show that DWETS has a positive impact on ash removal efficiency and does not have any negative impact on the electrostatic precipitator (ESP), flue gas heat exchanger and WFGD. The pH values of the slurry of WFGD slightly increase when the DWETS is running. The simulation and field test of the DWETS show that it is a feasible future technology for desulfurization wastewater treatment.

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NOx process inhibition and energy efficiency improvement in new swirl modification device for steel slag based on coal combustion

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2018-0007 ◽

2018 ◽

Vol 16 (7) ◽

Author(s):

Junxiang Guo ◽

Lingling Zhang ◽

Daqiang Cang ◽

Liying Qi ◽

Wenbin Dai ◽

...

Keyword(s):

Energy Efficiency ◽

Flue Gas ◽

Coal Combustion ◽

Steel Slag ◽

Coal Ash ◽

Combustion Efficiency ◽

Gas Temperature ◽

Staged Combustion ◽

Energy Efficiency Improvement ◽

Swirl Combustion

Abstract In this study, a novel swirl combustion modified device for steel slag was designed and enhanced with the objective of achieving highly efficient and clean coal combustion and also for achieving the whole elements utilization of coal. Coal ash and steel slag were melted in the combustion chamber and subsequently entered the slag chamber. The detrimental substances solidified and formed crystals, which allowed for the comprehensive utilization of the ash and slag. Our experiments mainly aimed to mitigate the formation of NOx, while using the heat and slag simultaneously during the coal combustion without a combustion efficiency penalty. The increase in the device’s energy efficiency and reduction in the NOx emissions are important requirements for industrialization. The experiments were carried out in an optimized swirling combustion device, which had a different structure and various coal feeding conditions in comparison to previously reported devices. The fuel-staged and non-staged combustion experiments were compared under different coal ratios (bitumite:anthracite). For the fuel-staged combustion experiments, the NOx concentration in the flue gas was observed to decrease significantly when the coal ratio of 1:1, an excess air coefficient of 1.2, and a fuel-staged ratio of 15:85 were used. Under these conditions, the flue gas temperature was as high as 1,620°C, while the NOx concentration was as low as 320 mg/m3 at 6 % O2. The air-surrounding-fuel structure that formed in the furnace was very beneficial in reducing the formation of NOx. In comparison to other types of coal burners, the experimental combustion device designed in this study achieved a significant reduction of NOx emissions (approximately 80 %).

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A Model for Calculating the Outlet Flue Gas Temperature of FGD Absorption Tower

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.130-134.3812 ◽

2011 ◽

Vol 130-134 ◽

pp. 3812-3816

Author(s):

Gang Xu ◽

Yao Tian ◽

Xing Yuan ◽

Yong Ping Yang

Keyword(s):

Theoretical Model ◽

Energy Balance ◽

Water Consumption ◽

Flue Gas ◽

Flue Gas Desulfurization ◽

Gas Temperature ◽

Significance Analysis

Theoretical model for calculating the outlet flue gas temperature of limestone-gypsum wet flue gas desulfurization (FGD) absorption tower is important for water consumption calculation. In this paper, the energy balance in the spray zone is analyzed and a model for calculating the outlet flue gas temperature of FGD absorption tower is proposed. An example computation of the outlet flue gas temperature of a typical 600MW class unit’s operation data is introduced, the result has verified the model. A further study of significance analysis has then been made to analyze and simplify the model.

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Reliable simple zonal method of the furnace thermal calculation

Thermal Science ◽

10.2298/tsci0502045i ◽

2005 ◽

Vol 9 (2) ◽

pp. 45-55

Author(s):

Vladan Ivanovic

Keyword(s):

Energy Consumption ◽

Flue Gas ◽

Thermal Load ◽

Operating Conditions ◽

Thermal Calculation ◽

Gas Temperature ◽

Zonal Method ◽

One Dimensional ◽

Furnace Performance ◽

Steam Boilers

The calculation of the furnace in the industrial and power boilers is the most important and the most responsible part of the thermal calculation, and it has important influence on the rationalization of energy consumption. In the paper one-dimensional zonal method of the furnace thermal calculation of steam boilers is presented. It can successfully define disposition of flue gas temperature and specific thermal load of screen walls with height of the furnace in case of uneven deposits distribution which vary in size and quality. Its greatest use is for comparing furnace performance under various operating conditions.

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Modelling Flue Gas Desulfurization Using Pyrolusite Pulp in a Jet Bubbling Reactor

Materials Science Forum ◽

10.4028/www.scientific.net/msf.610-613.85 ◽

2009 ◽

Vol 610-613 ◽

pp. 85-96 ◽

Cited By ~ 5

Author(s):

Jing Dong Zhao ◽

Shi Jun Su ◽

Nan Shan Ai ◽

Xiao Fan Zhu

Keyword(s):

Flue Gas ◽

Ph Value ◽

Scale Up ◽

Absorption Efficiency ◽

Flue Gas Desulfurization ◽

Process Conditions ◽

Gas Temperature ◽

Transfer Coefficients ◽

Set Up ◽

So2 Absorption

A mathematical model for flue gas desulfurization using pyrolusite pulp in jet bubbling reactor (JBR) was described. Firstly, based on the concept of two stages mass balance with chemical reaction, two models were set up, for jet bubbling zone and rising bubble zone, respectively, according to the construction of JBR. The models consist of two coupling differential equations and were solved simultaneously by integral and separation of the variables. Then the SO2 absorption efficiency expression was developed, considering the great discrepancy existing between the gas-side mass transfer coefficients of the jet bubbling zone and gas bubble rising zone. The final expression associates SO2 absorption efficiency with process conditions and JBR structure parameters, which can give some instruction and guidance for the study of reactor operation process. Predicted results from the theoretical model, including effect of pH value of the pulp, flue gas temperature and inlet SO2 concentration of flue gas on SO2 absorption efficiency, were found to be in good agreement with experimental data obtained in a jet bubbling reactor. The model provides a basis for the process scale up and operating guide.

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