Measurement & Control of Pulverized Coal Concentration in Exhaust Pneumatic Convey System

Pulverized coal firing boilers are widely used in power plants. Coal is pulverized into very fine particles and then mixed with primary air in horizontal pipes in the case of exhaust pneumatic convey system. The pulverized coal particles are conveyed by primary air to the burner and burn in the furnace. The concentration of pulverized coal in primary air should be well controlled to keep the safe and economic operation of the boiler. Credible measuring and controlling system is needed in engineering applications. Investigation of the mixing process shows that the pressure of primary air drops rapidly within the process, which gives the possible way to determine the pulverized coal concentration. The rapid pressure drop is mainly due to the acceleration of the pulverized coal particles. With energy balance analysis, study of the relationship between the mass flow rate of the pulverized coal and the pressure changes within the mixing process is done. The governing equation is achieved and the method of using two sections to measure the flow is proposed. The measuring and controlling system can be established according to the method. As a result, the measuring and controlling method provides a new way to meet the needs of engineering application.

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Flow Measurement of Primary Air Containing Pulverized Coal with Simple Venturi Tube

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.986-987.1506 ◽

2014 ◽

Vol 986-987 ◽

pp. 1506-1509

Author(s):

Xing Sen Yang ◽

Jing Yin

Keyword(s):

Flow Measurement ◽

Power Plants ◽

Thermal Power ◽

Pulverized Coal ◽

Venturi Tube ◽

Thermal Power Plants ◽

Coal Particles ◽

Safe State ◽

Coal Flow ◽

Remarkable Deviation

The flow measurement of primary air is very important for thermal power plants to maintain the safe state of operation. For direct firing pulverizing system, the measuring is essentially affected by pulverized coal particles. Abrasion and occlusion would bring great trouble to the measurement. Many measuring methods are invalid under that circumstance. Lots of efforts have been made to find appropriate ways to measure the flow of primary air containing pulverized coal. Venturi tube had been successfully used to measure the flow of air. If a venturi tube is used to measure the flow velocity of primary air, the differential pressure goes higher with the increase of the concentration of pulverized coal in the primary air. The neglect of the affection of pulverized coal on the measuring would result in remarkable deviation. With the aids of coal flow rate, a method of using venturi tube to measure the velocity of primary air containing pulverized coal was established. The affection of pulverized coal on flow measuring of primary air cannot be ignored.

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Co-firing of gas coal dust fine particles and synthetic peat gas. Part 1. Simulation of processes of steam-air gasification of peat in a fixed bed and combustion of dust and gas mix in a stream

Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu ◽

10.33271/nvngu/2021-6/057 ◽

2021 ◽

pp. 57-65

Author(s):

B.B Rokhman ◽

N.I Dunayevska ◽

V.G Vyfatnuik ◽

I.V Beztsennyi

Keyword(s):

Solid Fuel ◽

Fine Particles ◽

Coal Dust ◽

Fixed Bed ◽

Particle Diameter ◽

Pulverized Coal ◽

Mirror Reflection ◽

Time Interval ◽

Coal Particles ◽

Thermochemical Processing

Purpose. To build a model of solid fuel gasification in a fixed bed taking into account the velocity of particles, which allows obtaining detailed information about the technological process. To develop an optimal technological scheme of co-firing of pulverized coal particles and peat gas in the TPP-210A boiler. To investigate the process of a binary mix burning. Methodology. The objects of research were pulverized coal of Ukrainian deposits and peat from Volyn region deposits. The developed model was used to calculate the peat gasification process. To study the process of burning a binary blend, ANSYS FLUENT package was used. Findings. A model of solid fuel gasification in a fixed bed has been developed, which differs from the existing models by taking into account the particle velocity and its change. With the aid of this model the detailed information on temperature and concentration fields of the two-phase environment is received. The process of burning binary mix in a TPP-210A boiler is investigated. Originality. It was found that in the time interval 2200 < < 3200 s a stable stationary process of thermochemical processing of peat with q4.1 = 0.130.3% is formed. The profile of the dispersed phase velocity distribution resembles a mirror reflection of the profile of the particle diameter dependence. Practical value. Using the constructed model, the process of thermochemical processing of 28939 kg/h of raw peat in three reactors with a fixed bed at a pressure of 1.5 MPa was numerically investigated. The composition of the generator gas at the reactor outlet was determined.

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Numerical investigation using two different CFD codes of pulverized-coal combustion process characteristic in an industrial power plant boiler

E3S Web of Conferences ◽

10.1051/e3sconf/20198201009 ◽

2019 ◽

Vol 82 ◽

pp. 01009

Author(s):

Paweł Madejski ◽

Norbert Modliński

Keyword(s):

Numerical Modeling ◽

Coal Combustion ◽

Power Plants ◽

Fluid Dynamic ◽

Combustion Process ◽

Pulverized Coal ◽

Front Wall ◽

Coal Particles ◽

Boiler Operation ◽

Steam Boilers

Steam boilers using the coal as a basic fuel are still one of the most important techniques used to generate electricity in Power Plants. Many activities connected with optimization of steam boilers operation, investigation of combustion efficiency using different fuels, control and reducing pollutants emission are observed. Numerical modeling of large steam boilers using Computational Fluid Dynamic method can be a very way to develop and verify effects of all activities regarding combustion process optimization. Numerical modeling results of the coal combustion process in the front wall coal-fired boiler are presented in the paper. The behavior of the flow of pulverized coal through the burners was analyzed, and the temperature and velocity distribution in the combustion chamber were reproduced in the simulation. Despite the fact that the attention has been focused on boiler simulation at nominal load, it is possible to perform numerical studies concerning the analysis of coal combustion at different boiler loads (minimum load and flexible boiler operation). Analysis of different fuels and their impact on the combustion process, as well as analysis of coal mills operation, coal particles size distribution and they impact on boiler operation can be performed using developed models.

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Life Cycle Analysis: Sub-Critical Pulverized Coal (SubPC) Power Plants

10.2172/1542447 ◽

2018 ◽

Author(s):

Timothy J Skone ◽

Greg Schivley ◽

Matthew Jamieson ◽

Joe Marriott ◽

Greg Cooney ◽

...

Keyword(s):

Life Cycle ◽

Life Cycle Analysis ◽

Power Plants ◽

Pulverized Coal

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Comprehensive energy balance analysis of photon-enhanced thermionic power generation considering concentrated solar absorption distribution

Solar Energy Materials and Solar Cells ◽

10.1016/j.solmat.2021.111067 ◽

2021 ◽

Vol 226 ◽

pp. 111067

Author(s):

A.N.M. Taufiq Elahi ◽

Devon Jensen ◽

Mohammad Ghashami ◽

Keunhan Park

Keyword(s):

Power Generation ◽

Energy Balance ◽

Solar Absorption ◽

Balance Analysis ◽

Energy Balance Analysis

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Mass and Energy Balance Analysis of Methanol Production Using Atmospheric CO2 Capture with Energy Source from PCMSR

E3S Web of Conferences ◽

10.1051/e3sconf/20184201004 ◽

2018 ◽

Vol 42 ◽

pp. 01004

Author(s):

Andang W. Harto ◽

Mella Soelanda

Keyword(s):

Energy Source ◽

Global Warming ◽

Co2 Capture ◽

Co2 Sequestration ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Methanol Production ◽

Sufficient Energy ◽

Balance Analysis ◽

Energy Balance Analysis

The rising of atmospheric CO2 concentration is the major source to global warming system. Many methods have been proposed to mitigate global warming, such as carbon penalty, carbon trading, CO2 sequestration, etc. However these proposed methods are usually uneconomical, i.e., these methods do not produce economic valuable substances. This paper will propose a method to absorb atmospheric CO2 to produce economic valuable substances such as methanol, dimethyl ether, ethylene, several hydrocarbon substances and derivatives and several graphite substances. This paper is focused on methanol production using atmospheric CO2 capture. The overall process is endothermic. Thus a sufficient energy source is needed. To avoid more CO2 emission, the energy source must not use conventional fuels. To assure the continuity of energy deliberation, nuclear energy will be used as the energy source of the process. In this paper, the Passive Compact Molten Salt Reactor (PCMSR) will be used as the energy source. The 460 MWth PCMSR is coupled with atmospheric CO2 capture, desalination, hydrogen production and methanol production facilities. The capturing CO2 capacity is 7.2 ton/h of atmospheric CO2. The valuable outputs of this system are 3.34 ton/h of H2, 34.56 ton/h of O2, 5.24 ton/h of methanol and 86.74 MWe of excess electricity.

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Numerical Simulation on Improving NOx Reduction Efficiency of SNCR by Regulating the 3-D Temperature Field in a Furnace

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.807-809.1505 ◽

2013 ◽

Vol 807-809 ◽

pp. 1505-1513 ◽

Cited By ~ 2

Author(s):

Amir A.B. Musa ◽

Xiong Wei Zeng ◽

Qing Yan Fang ◽

Huai Chun Zhou

Keyword(s):

Numerical Simulation ◽

Temperature Field ◽

Removal Efficiency ◽

Pulverized Coal ◽

Measuring System ◽

Optimum Temperature ◽

Utility Boiler ◽

Coal Particles ◽

Injection Zone ◽

Reduction Efficiency

The optimum temperature within the reagent injection zone is between 900 and 1150°C for the NOX reduction by SNCR (selective non-catalytic reduction) in coal-fired utility boiler furnaces. As the load and the fuel property changes, the temperature within the reagent injection zone will bias from the optimum range, which will reduces significantly the de-NOX efficiency, and consequently the applicability of SNCR technology. An idea to improve the NOX reduction efficiency of SNCR by regulating the 3-D temperature field in a furnace is proposed in this paper. In order to study the new method, Computational fluid dynamics (CFD) model of a 200 MW multi-fuel tangentially fired boiler have been developed using Fluent 6.3.26 to investigate the three-fuel combustion system of coal, blast furnace gas (BFG), and coke oven gas (COG) with an eddy-dissipation model for simulating the gas-phase combustion, and to examine the NOX reduction by SNCR using urea-water solution. The current CFD models have been validated by the experimental data obtained from the boiler for case study. The results show that, with the improved coal and air feed method, average residence time of coal particles increases 0.3s, burnout degree of pulverized coal increases 2%, the average temperature at the furnace nose decreases 61K from 1496K to 1435K, the NO emission at the exit (without SNCR) decreases 58 ppm from 528 to 470 ppm, the SNCR NO removal efficiency increases 10% from 36.1 to 46.1%. The numerical simulation results show that this combustion adjustment method based on 3-D temperature field reconstruction measuring system in a 200 MW multi-fuel tangentially fired utility boiler co-firing pulverized coal with BFG and COG is timely and effective to maintain the temperature of reagent injection zone at optimum temperature range and high NOX removal efficiency of SNCR.

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