Transcript Modeling of fugitive dust emission and control measures in stone

Modeling of fugitive dust emission and
control measures in stone crushing industry
專題討論
碩一
79842001
劉昱麟
Abstract
• A cluster of 72 stone crushing units located at Trisoolam in
Chennai is a source of high levels of dust generation in the
vicinity of the crushers and in the communities surrounding
them.
• FDM, ISCST3 and AERMOD were employed for prediction of
dust emission from stone crushers on the surrounding areas.
• The control measures adopted at these stone crushing units are
not sufficient enough to bring down the concentration within
the stipulated limits.
Materials and methods
•
•
•
•
•
•
•
•
•
Weather monitoring
Ambient air quality monitoring network design
Air quality monitoring
氣象監測
Particle size analysis
鄰近空氣品質監測系統
Emission rate estimation
空氣品質監測
Assessment of occupational exposure level 粒徑分析
估算排放率
Modeling of fugitive dust emissions
職業性暴露性層級評估
Data requirements of the models
模式應用
Model prediction
模式參數設定
模式模擬預測
Study area
TSPM 總懸浮顆粒物
RSPM 可吸入懸浮顆粒物
• Weather monitoring
Wind speed
Wind direction
Temperature
Pressure
Rainfall
Humidity
風速
風向
氣溫
氣壓
降雨
濕度
• Ambient air quality monitoring network design
17 sites across the area
10 location at stone crushing units
7 in ambient air
Modeling of fugitive dust emissions(1/3)
•
FDM(揚塵擴散模式)
1.
Computerized Gaussian plume air quality dispersion model
2.
Three basic types of sources: point, line, and area
3.
Designed for estimation of concentrations and deposition impacts from
fugitive dust sources.
4.
Gravitational settling velocity and deposition velocity are calculated.
Modeling of fugitive dust emissions(2/3)
•
ISCST3(工業污染短期模式)
1.
Based on the straight line, steady state Gaussian plume equation.
2.
Three basic types of sources: point, volume, and area.
3.
Estimates the concentration or deposition value for each source and
receptor combination for each hour of input meteorology, and calculates
user selected short term averages.
4.
Includes a new wet deposition algorithm and also incorporates the
COMPLEX1 screening model algorithms.
Modeling of fugitive dust emissions(3/3)
•
AERMOD(美國環境保護逸散模式)
1.
It serves as a complete replacement for ISCST3.
2.
It assumes the concentration distribution to be Gaussian in both the
vertical and horizontal in the stable boundary layer (SBL), but the
vertical distribution is described to bi- Gaussian probability density
function in the convective boundary layer.
3.
The major improvements that AERMOD brings to applied dispersion
modeling is its ability to characterize the Planetary Boundary Layer
(PBL) through both surface and mixed layer scaling.
Model prediction
1.
2.
3.
4.
5.
6.
Emission rate
Particle size distribution of dust
Meteorology
Source-receptor geometry
Treatment for deposition
Scavenging effect
Result and discussion
•
•
•
•
•
•
•
•
Weather monitoring
concentration at source
Air quality monitoring Dust
Dust concentration around stone crushing units
Particle size analysis
Emission rate estimation
Assessment of occupational exposure level
Model prediction
Control measures
Impact zone
• Weather monitoring
direction in southwest 19%
direction in west 18.5%
direction in west of southwest 14%
wind speed in 5~10kmph 25%
wind speed in 10~15kmph 15%
ave. wind speed is 9.65kmph
Air quality monitoring (Dust concentration at source)
Air quality monitoring
(Dust concentration around stone crushing units)
Particle size analysis
PM30 73.5％
PM15 45％
PM2.5 14.3％
• Emission rate estimation
micro-meteorological condition
location of source and receptor
upwind and downwind direction
3.89g/s ＞ 2.778g/s(USEPA)
• Assessment of occupational exposure level
3 for total)
職業安全與健康機構
(15mg/m
Occupational
Safety and Health
Administration
3 for
National
Institute of Occupational
Safety
andTSPM)
Health
國家安全與健康協會
(10mg/m
American
Conference of Governmental
Industrial
美國政府工業衛生聯盟
(10mg/m3 for
TSPMHygienists
& RSPM)
Indian
Factory Act.
印度工業法規
EXCESS
Model prediction
Model prediction
Control measures
Control measures
Implementation of following pollution control measures at source
1.
2.
3.
4.
Dust containment cum suppression system for the equipment
Construction of wind breaking walls
Construction of metalled roads within the premises
Regular cleaning and wetting of the ground within the premises
Growing of a green belt along the periphery
In addition the following good house keeping were also implemented
to further reduce the dust emissions
1. Reducing drop heights
2. Spray nozzle for periodical wetting of dust
3. Collection of fine powder below ground level and completem
covering
4. Covering of loaded trucks using tarpaulins while transportation
5. Arresting re-entrainment of settled dust from surfaces
Impact zone
N 風向
N 風向
E
W
S
E
W
S
Conclusion
• The adequacies of the control measures is not
sufficient enough to bring down the concentration
within stipulated limits in residential areas located
less than 300 m from stone crushing activity in the
eastern direction.
• There is a scope for further improvement of control
measures at these stone crushing units in Trisoolam
area.