Transcript Environmental Emissions: Industry and Automobiles

Environmental Emissions:
Industry and Automobiles
DR. MD. EHSAN
CES, BUET, NOV 2009
Environmental Pollution
“Environmental Pollution” is the introduction of contaminants into an
environment that causes instability, disorder, harm or discomfort to the
ecosystem i.e. physical systems or living organisms.
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How is Contributing Most to Environmental Pollution ?
The major contribution to the environmental pollution comes from only a few
countries. Several countries in the developed world are the leaders in air
polluting emissions.
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Environmental Emissions:
This includes Gas-borne pollutants discharged into the atmosphere from different manmade or natural sources eg. - Smokestacks of Industrial and Power generation plants,
Exhaust from Vehicles, Burnt Gases from Bushfires or Volcanic Irruptions.
Air pollution comes from both natural and man made sources. Though globally man
made pollutants from combustion, construction, mining, agriculture and warfare are
increasingly significant in the air pollution equation. Motor vehicle emissions are one of
the leading causes of air pollution.
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“Global Warming” due to “Green House Effect” is the consequence of continuous large
scale environmental emissions and mainly responsible for gradually increasing the
temperature the earth’s atmosphere. World wide this is becoming the highest
environmental concern today. The polluting gases that contribute to Global Warming are
termed as Green House Gases (GHG).
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Constitution of Industrial Emissions:
Industrial Emissions is a broad term covering many process which involves fossil fuel combustion.
This includes - Industry, Residential heating, Transportation (cars, trucks, and airplanes), Power
Generation Utilities, and Commercial heating. Fossil fuels include coal, oil, natural gas, and
gasoline. Two other processes are also usually included with industrial emissions. The first is the
production of cement, which releases large amounts of CO2 as the limestone is prepared. The
second item is gas flaring from oil fields.
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Air Quality Index
The Air Quality Index (AQI) is an index (that is, a numerical value or ratio derived from a
series of observations) for reporting daily air quality. It tells you how clean or polluted your
air is, and what associated health effects might be a concern for you. The purpose of the
AQI is to help you understand what local air quality can mean to your health. To make it
easier to understand, the AQI is divided into six categories:
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Industrial Emission Standards : Limits of Pollutants
Substances
Sources
Units
Standard Values
Antimony
Any source
mg/Nm3
20
Arsenic
Any source
mg/ Nm3
20
Carbon monoxide
Any source
mg/ Nm3 or ppm
1000 or 870
Chlorine
Any source
mg/ Nm3
30
Copper
Furnace or smelter
mg/Nm3
30
Hydrogen Chloride
Any source
mg/Nm3
200
Hydrogen Sulphide
Any source
mg/Nm3 or ppm
140 or 100
Lead
Any source
mg/Nm3
30
Mercury
Any source
mg/Nm3
30
Oxides of Nitrogen
Boiler / - Coal as fuel
mg/Nm3 or ppm
940 or 500
Oxides of nitrogen
Boiler / -Others fuel
mg/Nm3 or ppm
470 or 250
Particulate
Boiler & Furnace / Coal as fuel
mg/Nm3
400
Particulate
Boiler & Furnace / - Others
fuel
mg/Nm3
400
Particulate
Boiler & Furnace / - Heavy oil
as fuel
mg/Nm3
300
Particulate
Steel/ Aluminum
Manufacturing
mg/Nm3
300
Particulate
Other source
mg/Nm3
400
Sulfur-di-oxide
H2SO4 production
mg/Nm3 or ppm
3000 or 500
Sulfuric acid
Any source
mg/Nm3 or ppm
100 or 25
Xylene
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Any source
3 or ppm
BUET, NOV
2009
mg/Nm
870 or 200
Ways of Controlling and Mitigating Environmental Emissions
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More Efficient Systems : Better machines or Operating Processes are used.
Less fuel needs to be burned, Less Green hours gases would be produced.
Reduction of Energy Wastage : Using the Energy better, involves loss
minimization after energy being produced.
Removing Green House Gases : Carbon Capture and Storage (CCS)
Technology.
Use Renewable and Non-Polluting Source More : Technology needs to be
further developed and commercialized.
Recycle Material as much as possible: Reduces energy requirement for
new materials.
Economic Incentives : Efficient energy user must be encouraged by policy.
Motivation and Awareness : Increasing public awareness through education
and incentives.
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Emission from Motorized Vehicles
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Emission from Internal Combustion Engines
Expected Products :
CO2 and H2O, as the fuels are hydrocarbons.
Undesirable Products : CO, Unburned HC, NOx , PM, SOx , Pb
Major Emission Concerns :
SI Engines : CO, Unburned HC, NOx, Pb
CI Engines : PM, NOx, Unburned HC, SOx
Unburned HC :
Major Concern for SI engines.
Could be as high as 6000 ppm, 1.5% of fuel
Constitutes of fuel itself and partially reacted components.
Causes of Formation :
Non-Stoichiometric AF ratios of combustion
Incomplete combustion, EGR
Crevice volumes
Valve Overlap
Oil or deposition on combustion chamber wall
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Carbon Monoxide (CO) :
Major Concern for SI engines.
Could be as high as 5% of exhaust volume.
Causes of Formation : Non-Stoichiometric AF ratios of combustion,
Incomplete combustion, EGR
Nitrogen Oxides :
Major Concern for both SI and CI engines.
Could be as high as 2000 ppm
Constitutes of NO and NO2
Causes of Formation :
High temperature of combustion
Availability of excess Oxygen at high temp
Highest rate at slightly lean mixture (=0.95)
Photo-Chemical Smog : NO2 + Energy from Sunlight  NO + O  O + O2  O3 (Ground leve
Sulfur Oxides (SOx) :
Major Concern for CI engines.
Causes of Formation : Sulfur in fuel SI (150-600 ppm), CI (5000 ppm-1%)
LSD (low sulfur diesel), ULSD (Ultra low sulfur diesel < 50ppm)
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Particulate Matter (PM) :
Major Concern for CI engines, may be in SI engines at high loads.
High concentration effects the opacity of exhaust (smoke)
Constitutes of Carbon Soot Particle, coated with SO3 and Soluble Organic
Fractions (SOF) of fuel.
Average mean diameter – 10 m (PM 10), 2.5 m (PM 2.5)
Smaller the size more is the health hazard.
Causes of Formation :
Near-Stoichiometric AF ratios of combustion
Presence of heavy components in the fuel
Richer burning at high loads
At higher temperatures :
PM  but NOX 
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Emission Standards :
Emission Standards may vary in different countries. The standards are getting stringent day by day.
EURO stand.
CARB stand.
FTP stand.
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EPA stand.
Mode stand.
Emission Measurement : Gas Analyzers
These are instantaneous vehicle emission measuring devices. Typically have Infrared
and Electro-Chemical sensors for measurement of gas components.
3-Gas Analyzers : CO2 , CO and HC
4-Gas Analyzers : CO2 , CO, HC and remaining Oxygen
5-Gas Analyzers : CO2 , CO, HC, remaining Oxygen and NOx
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Emission Control Techniques
Pre-Engine System
In-Engine System
Post-Engine System
: Hot Air Intake System
: Electronic Fuel Injection, Exhaust Gas Recirculation
: Catalytic Converter, Diesel Particulate Filter
CC : Post Engine Emission Control Device Used for Petrol Vehicles
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Diesel Particulate Filters
DPF : Post Engine Emission Control Device used for Diesel run Vehicles
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Thank You

Let us all work for a better Environment
CES, BUET, NOV 2009