International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 03 | Mar 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 3481
EXPERIMENTAL INVESTIGATION OF EXHAUST EMISSIONS USING CATALYTIC
CONVERTER
T.Ravi Kumar
1
, D.Tejo Venkata Kumar
2
, K.Sarachandra
3
, M.Chakravarthi
4
, A.Satish
5
,
B.Dhana Suresh
6
1
Associate professor Department of Mechanical Engineering, DMSSVH College of Engineering, Machilipatnam,
Andhra Pradesh, India.
2-6
B.Tech students Department of Mechanical Engineering, DMSSVH College of Engineering, Machilipatnam,
Andhra Pradesh, India.
---------------------------------------------------------------------***----------------------------------------------------------------------
Abstract - Emissions from the automobile contribute to major air pollution problems in cities as well as villages along with
industrialized areas in developed and developing countries. Air pollution is one of the major factor that is the cause for global
warming and the climate change problems. This paper focuses on mitigation of these problems using catalytic convertor to reduce
the level of emissions of CO and HC in a diesel engine. Since most of the transportation vehicles rely solely on petrol and diesel for
their operation, this results in large amount of carbon monoxide (CO), un burnt hydrocarbons (HC), nitrogen oxides (NOx), and
particulate matters. Hence the experimental analysis of the catalytic converter is to study its effect in reduction of these toxicants.
Key Words: catalytic converter, redox reactions, BS norms, ppm
1. INTRODUCTION
Carbon monoxide is a poison that has high affinity toward haemoglobin. This reduces oxygen supply to the body leading to
carbon monoxide poisoning. Long term exposure to HC and NOx leads to smog , which, in the presence of light from sun, would
give rise to secondary pollutants like O3, NOx, which cause global environmental issues
[6]
. The pollutants have negative impact
on human health hence the stringent norms of pollutant emissions. As the emission standards were tightened, strategies were
applied such as the BS IV (Bharat Stage IV) emission norms, Euro VI norms, etc. The aim is to reduce levels of exhaust emissions
including NOx, CO, hydrocarbons, and particulate matter (PM) such as soot from diesel cars. Currently, the automobiles in India
are to achieve BS VI Norms for all vehicles from April 2020. BS IV& VI norms are emission control standards that are developed
on European regulations (Euro norms) but suitable for Indian conditions
[7]
. They set limits for air pollutants release from
equipment using IC engines. Carbon monoxide (CO) a colorless, odorless, tasteless, and toxic air is produced in the incomplete
combustion of carbon-containing fuels, such as gasoline, natural gas, oil, coal, and wood.CO may be a weak and direct
greenhouse emission but it contributes to a majority of effects in heating of earth's surface. Bio fuels emit certain amounts of
these toxicants, but relatively less than that of the fossil fuels
[5]
. Motor vehicles release a considerable portion of CO into the
atmosphere along with hydrocarbons. Hydrocarbons react in the presence of NOx and light from the sun to create ozone gas
that irritates eyes, damages lungs, and aggravates metabolic processes. Several exhaust HC’s are toxic, with potential to cause
cancer. These substances contribute to the greenhouse effect and global warming, deplete the ozone, increase occurrences of
cancer and metabolism disorders, scale back the photosynthetic capability of plant life and do much harm to ecosystems.
1.1 Catalytic Converter:
A catalytic convertor (figure1) is an emission control device that is used to convert harmful gases and pollutants in exhaust
from an IC engine into less harmful gases by redox reaction
[1]
. The convertors are used along with IC engine which is fueled by
either diesel or petrol. A three way catalytic convertor is used for the experimental analysis. As of the current scenario in the
automobile industry, a three way catalytic convertor is used widely to reduce HC, CO and NOx emissions which are formed
during the combustion process
[6]
. A three way catalyst runs three tasks simultaneously with each other. One catalyst is
responsible for the reduction of nitrogen oxide to both oxygen and nitrogen while the other catalyst is responsible for oxidation
of carbon monoxide to carbon dioxide and using unburned HC’s and oxidizing them to H2O andCO2.
The oxidation and reduction reaction takes place in the honeycomb monolithic structure. The role of the honeycomb structure
of the substrate is to increase the surface area covered by the catalyst layer exposed to the exhaust gases. The monolithic
structure is concealed with a thin layer of Rhodium as reduction catalyst and Palladium as oxidation catalyst. Platinum is also
present in traces which helps both oxidation and reduction reactions
[3]
. The reactions happen on the metal catalyst surface.
Vanadium is also used as an alternate catalyst material
[4]
. Hence greater the surface area, maximum conversion efficiency will
be achieved because the oxidation reactions depend on the surface on which species can absorb and react.