MODELING AND MEASUREMENT OF PARTICULATE MATTER (PM) COLLECTION FROM BOILER EXHAUST GAS IN ELECTROSTATIC WATER SPRAYING SCRUBBER

2021 ◽  
Vol 152 (A1) ◽  
Author(s):  
T H Ha ◽  
O Nishida ◽  
H Fujita ◽  
W Harano
Keyword(s):  
Particulate Matter ◽  
Collection Efficiency ◽  
Exhaust Gas ◽  
Mass Ratio ◽  
Gas Velocity ◽  
Combustion Source ◽  
Coal Fuel ◽  
New Guidelines ◽  
Lower Flow Rate ◽  
Good Agreement

Boiler exhaust gas consists of many components that cause air pollution, such as: particulate matter (PM), SOx, NOx, COx, etc. These pollutants normally are mixed. To eliminate them, an electrostatic water spraying scrubber is used, depending on a coal fuel used for combustion source in the furnace. For PM, new guidelines will be changed from the existing 10 to 2.5 microns within the next few years. The scrubber is widely used for the collection of PM from industrial exhausts because of its low equipment and maintenance costs combined with operational safety and high collection efficiency. This study presents computed and experimented results of PM collection efficiency in an electrostatic water spraying scrubber. In this scrubber electric attraction between charged PM and charged water droplet improves PM collection considerably over conventional scrubber. Computed model takes into account initial liquid momentum, hydrodynamic and electric forces. The effects of operating parameters, such as gas velocity, applied voltage, charge to-mass ratio on PM collection efficiency within the scrubber, were also investigated. Computed results are in good agreement with the experimental data obtained in the laboratory. Compared to inertial scrubbers, the electrostatic water spraying scrubbers can operate at lower flow rate, but total collection efficiency is over 98% of all PM sizes.

Study on the Contamination Coefficient of Convective Heating Surface in a Circulating Fluidized Bed Boiler

2013 ◽  
Vol 732-733 ◽  
pp. 286-290
Author(s):  
Yu Zhao Wang ◽  
Xue Min Liu ◽  
Ai Cheng Liu ◽  
Qing Liu ◽  
Jian Chun Zhang ◽  
...  
Keyword(s):  
Circulating Fluidized Bed ◽  
Collection Efficiency ◽  
Heating Surface ◽  
Surface Contamination ◽  
Convective Heating ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Gas Velocity ◽  
Cfb Boiler ◽  
Exhaust Gas Temperature

The ash deposition and the gas velocity affect the exhaust gas temperature of a CFB boiler. The surface contamination in a CFB boiler is quite different from that one in the pulverized coal boiler. It is suggested that the surface contamination in a CFB boiler should be determined according to the ash content in the fuel as well as the cyclone collection efficiency. The effect of the gas velocity on the surface contamination is very important. The lower gas velocity causes more serious contamination, leading to the higher exhaust gas temperature. The staged tube arrangement should be employed. And the gas velocity should be designed higher to enhance the self-cleaning ability. Anyway, the soot blower should be designed in the CFB boiler convective heating surface. The ratio of the practical contamination coefficient to the design one, k,is the strong function of gas velocity, wy, which was expressed as: k=1+exp(6.8-wy)

Implementing variable valve actuation on a diesel engine at high-speed idle operation for improved aftertreatment warm-up

2019 ◽  
Vol 21 (7) ◽  
pp. 1134-1146
Author(s):  
Kalen R Vos ◽  
Gregory M Shaver ◽  
Mrunal C Joshi ◽  
James McCarthy
Keyword(s):  
Particulate Matter ◽  
High Speed ◽  
Exhaust Valve ◽  
Exhaust Gas ◽  
Warm Up ◽  
Aftertreatment System ◽  
Idle Speed ◽  
Variable Valve Actuation ◽  
Brake Mean Effective Pressure ◽  
Valve Opening

Aftertreatment thermal management is critical for regulating emissions in modern diesel engines. Elevated engine-out temperatures and mass flows are effective at increasing the temperature of an aftertreatment system to enable efficient emission reduction. In this effort, experiments and analysis demonstrated that increasing the idle speed, while maintaining the same idle load, enables improved aftertreatment “warm-up” performance with engine-out NOx and particulate matter levels no higher than a state-of-the-art thermal calibration at conventional idle operation (800 rpm and 1.3 bar brake mean effective pressure). Elevated idle speeds of 1000 and 1200 rpm, compared to conventional idle at 800 rpm, realized 31%–51% increase in exhaust flow and 25 °C–40 °C increase in engine-out temperature, respectively. This study also demonstrated additional engine-out temperature benefits at all three idle speeds considered (800, 1000, and 1200 rpm, without compromising the exhaust flow rates or emissions, by modulating the exhaust valve opening timing. Early exhaust valve opening realizes up to ~51% increase in exhaust flow and 50 °C increase in engine-out temperature relative to conventional idle operation by forcing the engine to work harder via an early blowdown of the exhaust gas. This early blowdown of exhaust gas also reduces the time available for particulate matter oxidization, effectively limiting the ability to elevate engine-out temperatures for the early exhaust valve opening strategy. Alternatively, late exhaust valve opening realizes up to ~51% increase in exhaust flow and 91 °C increase in engine-out temperature relative to conventional idle operation by forcing the engine to work harder to pump in-cylinder gases across a smaller exhaust valve opening. In short, this study demonstrates how increased idle speeds, and exhaust valve opening modulation, individually or combined, can be used to significantly increase the “warm-up” rate of an aftertreatment system.

scholarly journals Particle Size Distribution of E-Cigarette Aerosols and the Relationship to Cambridge Filter Pad Collection Efficiency

2015 ◽  
Vol 26 (4) ◽  
Author(s):  
Steven L. Alderman ◽  
Chen Song ◽  
Serban C. Moldoveanu ◽  
Stephen K. Cole
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Propylene Glycol ◽  
Collection Efficiency ◽  
Transmission Measurement ◽  
Average Particle ◽  
Electrical Mobility ◽  
Total Particulate Matter

AbstractThe relatively volatile nature of the particulate matter fraction of e-cigarette aerosols presents an experimental challenge with regard to particle size distribution measure-ments. This is particularly true for instruments requiring a high degree of aerosol dilution. This was illustrated in a previous study, where average particle diameters in the 10-50 nm range were determined by a high-dilution, electrical mobility method. Total particulate matter (TPM) masses calculated based on those diameters were orders of magnitude smaller than gravimetrically determined TPM. This discrepancy was believed to result from almost complete particle evaporation at the dilution levels of the electrical mobility analysis. The same study described a spectral transmission measurement of e-cigarette particle size in an undiluted state, and reported particles from 210-380 nm count median diameter. Observed particle number concentrations were in the 10Described here is a study in which e-cigarette aerosols were collected on Cambridge filters with adsorbent traps placed downstream in an effort to capture any material passing through the filter. Amounts of glycerin, propylene glycol, nicotine, and water were quantified on the filter and downstream trap. Glycerin, propylene glycol, and nicotine were effciently captured (> 98%) by the upstream Cambridge filter, and a correlation was observed between filtration efficiency and the partial vapor pressure of each component. The present analysis was largely inconclusive with regard to filter efficiency and particle-vapor partitioning of water. [Beitr. Tabakforsch. Int. 26 (2014) 183-190]

scholarly journals Gas hold-up in a three-phase reciprocating plate column

2005 ◽  
Vol 70 (11) ◽  
pp. 1363-1371 ◽  
Author(s):  
Ljubisa Nikolic ◽  
Vesna Nikolic ◽  
Vlada Veljkovic ◽  
Dejan Skala
Keyword(s):  
Solid Phase ◽  
Liquid System ◽  
Column Diameter ◽  
Gas Velocity ◽  
Vibration Intensity ◽  
Three Phase ◽  
Superficial Gas Velocity ◽  
Phase Column ◽  
Plate Column ◽  
Good Agreement

The influence of the geometry of a reciprocating plate column (diameter), superficial gas velocity, vibration intensity and content of the solid phase in the column on the gas hold-up in a three phase column (G-L-S) were investigated in this study. For comparison, the gas hold-up was also analyzed in a gas-liquid system (G-L) in the same type of column. Good agreement between the experimentally determined values of the gas hold-up and those calculated on the basis of the derived correlation for the G-L and G-L-S system was obtained.

scholarly journals Simultaneous particulate matter and nitrogen oxide emission reduction through enhanced charge homogenization in diesel engines

2018 ◽  
Vol 22 (5) ◽  
pp. 2039-2052 ◽  
Author(s):  
Urban Zvar-Baskovic ◽  
Rok Vihar ◽  
Samuel Rodman-Opresnik ◽  
Tomaz Katrasnik
Keyword(s):  
Particulate Matter ◽  
Low Temperature ◽  
Diesel Fuel ◽  
Minor Effect ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Engine Control ◽  
Pyrolysis Oil ◽  
Trade Off ◽  
Temperature Combustion

In the presented study, low temperature combustion was established with a direct injection of diesel fuel being a representative of high reactivity fuels and tire pyrolysis oil being a representative of low reactivity fuels. Tire pyrolysis oil was tested as a potential waste derived fuel for low temperature combustion, as it features diesel-like physical properties and lower cetane number compared to diesel fuel. The goal of this study was determination of suitable injection strategies and exhaust gas re-circulation rates to explore potentials of both fuels in reducing emissions in low temperature combustion modes. It was demonstrated that relatively small changes in the engine control strategy possess the potential to significantly improve NOx/particulate matter trade-off with minor effect on engine efficiency. In addition, low temperature combustion was for the first time successfully demonstrated with tire pyrolysis oil fuel, however, it was shown that lower re-activity of the fuel is by itself not sufficient to improve NOx /soot trade-off compared to the diesel fuel as entire spectra of fuel properties play an important role in improving NOx /soot trade-off. This study thus establishes relations between different engine control strategies, intake manifold pressure and exhaust gas recirculation rate on engine thermodynamic parameters and engine-out emissions while utilizing innovative waste derived fuel that have not yet been analysed in similar combustion concepts.

scholarly journals The Paths of the Suspended Particulate Inorganic and Organic Matter in a Small Urban Estuary: The Aarhus Harbour Estuary

1986 ◽  
Vol 17 (1) ◽  
pp. 31-46 ◽  
Author(s):  
K. B. Kronvang ◽  
C. Christiansen
Keyword(s):  
Organic Matter ◽  
Particulate Matter ◽  
Organic Content ◽  
Temporal And Spatial Distribution ◽  
Urban Estuary ◽  
Inorganic Matter ◽  
Organic Sediment ◽  
Suspended Particulate ◽  
Good Agreement ◽  
Inorganic And Organic

The nverine supply of suspended inorganic and organic sediment, its temporal and spatial distribution and its exchange with the bay, were estimated for an urban estuary (Aarhus Harbour Estuary, Denmark) during 1983-84. The river supplies high levels of particulate matter to the estuary. Export from the estuary averages one fifth of the river introduced particulate matter resulting in the accumulation of terrigenous material in the estuary. River discharge determines whether the high depletion of particulate matter in the upper estuary follows an exponential(flocculation) or a lineary curve (dilution). Preferential deposition of organic as opposed to inorganic matter in the upper estuary depletes the particulate matter of organic matter and associated pollutants. The estuary is divided into three depositional zones identified on the basis of sediment activity, grain-size and organic content. A sediment budget is precented for the estuary. Good agreement is shown between the actually dredged sediment quantity and the mass to sedimentation from the budget.

scholarly journals Evaluation of Bio-drying Process of Sewage Sludge using Mathematical Model of Heat and Mass Balance: Effects of Temperatures of Supplied Air and Exhaust Gas

2020 ◽  
Vol 42 (11) ◽  
pp. 580-591
Author(s):  
Jae-Ram Park ◽  
Dong-Hoon Lee ◽  
Kyung-Hyun Kim
Keyword(s):  
Sewage Sludge ◽  
Mass Balance ◽  
Air Temperature ◽  
Exhaust Gas ◽  
Moisture Removal ◽  
Mass Ratio ◽  
Gas Temperature ◽  
Drying Process ◽  
Exhaust Gas Temperature ◽  
Efficiency Indicators

Objectives : The effects of temperatures of supplied air and exhaust gas on moisture removal in the bio-drying process of sewage sludge were assessed by simulating the process. We also suggested performance and efficiency indicators for moisture removal in this process and identified their effectivity.Methods : The bio-drying process of sewage sludge was simulated by mathematical modeling of heat and mass balance under different combinations of supplied-air temperatures and control ranges of exhaust gas temperatures. The simulation results were analyzed by using some indicators for assessing the performance and efficiency of moisture removal.Results and Discussion : While BVS (biodegradable volatile solid) degradation was inhibited at a higher supplied-air temperature and a lower control range of exhaust gas temperature, moisture reduction was enhanced at the supplied-air temperature nearer to ambient and the controlled exhaust gas temperature for 45 to 50℃. The drying performance could be improved by the utilization of both metabolic heat and convective heat from hot supplied-air for the source of heat necessary for moisture removal. We suggested the moisture removal rate as a performance indicator, and both the moisture removing capacity of supplied-air and the mass ratio of moisture removal to BVS degradation as an efficiency indicator. We identified that this mass ratio could be an alternative for thermal efficiency of drying.Conclusions : It is effective to control the air-flow rate to keep the exhaust gas temperature within 45~50℃ during bio-drying of sewage sludge in terms of drying performance and efficiency. It is expected that a specified range or minimum required value for the performance and efficiency indicators in the bio-drying process which suggested in this study needs to be established.

A System of Selective Non Catalytic Reduction of NOx for Diesel Engine

2011 ◽  
Vol 201-203 ◽  
pp. 643-646 ◽  
Author(s):  
Bo Yan Xu ◽  
Hai Ying Tian ◽  
Jie Yang ◽  
De Zhi Sun ◽  
Shao Li Cai
Keyword(s):  
Catalytic Reduction ◽  
Three Dimensional ◽  
Exhaust Gas ◽  
Test Results ◽  
Practical Application ◽  
Three Dimensional Model ◽  
Reduction Efficiency ◽  
Different Temperatures ◽  
Reduction Of Nox ◽  
Good Agreement

SNCR (Selective Non Catalytic Reduction) system is proposed, with 40% methylamine aqueous solution as reducing agent to reduce NOx in diesel exhaust gas. The effect of injection position and volume on the reduction efficiency through the test bench is systematically researched. A three-dimensional model of a full-sized diesel SNCR system generated by CFD software FIRE is used to investigate the reduction efficiency under different temperatures. The simulated results have a good agreement with the test results, and it can be used to optimize SNCR system. The results can indicate the practical application of this technology.

Optical band-gap of TiO2 nanopowders doped with Al2O3

2013 ◽  
Vol 1493 ◽  
pp. 281-286
Author(s):  
Keisuke Yoshimura ◽  
Tetsuya Hashimoto ◽  
Hiroshi Katsumata
Keyword(s):  
Band Gap ◽  
Ball Mill ◽  
Milling Time ◽  
Optical Band Gap ◽  
The Other ◽  
Mass Ratio ◽  
Quantum Size ◽  
Powder Mass ◽  
Tio2 Nanopowders ◽  
Good Agreement

ABSTRACTOptical band-gap and cathode luminescence (CL) properties of anatase TiO2 nanopowders mixed with γ- Al2O3 powders by planetary ball mill were evaluated as a function of a powder mass ratio (x=Al2O3/TiO2) of 0 to 0.5 and their correlation with XRD spectra was also investigated. The optical band-gap of TiO2 increased from 3.36 eV to 3.41eV with increasing milling time (tm) up to 600 min, which was in good agreement with the blue shifts observed in the CL spectra with increasing tm and it was interpreted as a quantum size effect. In addition, the optical band-gap of TiO2 powders mixed with Al2O3 with tm=60min greatly increased from 3.36 eV to 3.48 eV with increasing x up to x=0.5. On the other hand, the optical band-gap of all the powders was decreased by annealing at temperatures above 600°C, which was evidenced by the XRD spectra to be due to the growth of grain size.

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