International Journal of Scientific & Engineering Research Volume 3, Issue 1, January-2012 1

ISSN 2229-5518

Anticipating Emission & Suggestions For

Reducing Exhaust Emissions With CNSL As Fuel

Prof.Paresh K. Kasundra, Dr. Ashish V. Gohil

Abstract- Bio-diesel is produced by mixing vegetable or animal oil with a small quantity of methanol in a process known as esterification. Bio-diesel is a promising nontoxic and biodegradable renewable alternative fuel compared to petroleum diesel in the light of the limited nature of fossil fuel and the environmental concerns.

The biodiesel is reported to be sulfur-free, nontoxic, biodegradable oxygenated and renewable. and the characteristics of biodiesel are very close to diesel fuel and some are better then diesel such as higher cetane number, no aromatics, almost no sulfur, and more then 10% oxygen by weight, which reduce the emission of carbon monoxide (CO), hydrocarbon(HC), particulate sulfur oxides(Sox) and volatile organic compounds(VOCs).although there are some advantages of using biodiesel instead of petroleum based diesel that biodiesel blends up to a maximum 5% should not cause engine and fuel system problem. so it can be seen that the properties of biodiesel can affect the engine performance and emissions. So in this paper we discussed anticipating emission and suggestions for reducing exhaust emissions with CNSL as a fuel in CI engine.

Index Terms: - biodiesel, vegetable oil, esterification, diesel engine performance, emissions.

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1 . 1 ( 1 ) A n t i c i p a t i n g E m i s s i o n w i t h C N S L A s

F u e l

As not much literature is found regarding CNSL hence
the kind of emissions that will be encountered while using
CNSL as fuel in diesel engine will have to be anticipated. As from the structure of CNSL it can be easily said that fuel contains higher levels of aromatics and cetane number will
be subsequently low, literature is studied for effects of cetane number and aromatics on emission of diesel engine. Spreen et al. conducted experiments on a prototype 1994
Navistar DTA-466 heavy-duty engine. This engine was an in-line 6-cylinder configuration of 7.6 liter displacement with compression ratio of 17:5:1 and had a DI combustion Chamber. They then construed certain statistical models, which were used to estimate independent effect of cetane number, aromatics and oxygen content of the fuel on the emissions. A similar experiment was done by Ullman et on a 1994 prototype DDC series 60 heavy-duty engine. This was a DI engine with an in-line 6-cylinder configuration of
11.1-liter displacement and compression ratio 16:1 [1]. Cetane number was determined to be most important fuel variable associated with emission of HC, CO, and NOX whereas fuel aromatics significantly affected PM emissions and was also observed changing emission of HC and NOX. Oxygen content in the fuel was important for estimating PM emission [1,2]. The statistical models are not include in the study but their results are presented below and there implication on CNSL as a fuel is stated.

U n b u r n t H y d r o c a r b o n s

They estimated using statistical models that an
independent increase of cetane number by 10 reduces
composite HC levels by 0.037 g/hp-hr. Decreasing
aromatics by 10% was estimated to reduce HC levels by
0.014 g/hp-hr. Adding 2% by weight oxygen to the fuel
using monoglyme was estimated to increase emissions by
0.051 g/hp-hr.

C a r b o n M o n o x i d e

Only Cetane number seemed to have certain effect on
CO emissions. An increase of 10 in cetane reduced CO
levels by 0.28 g/hp-hr.

N i t r o g e n O x i d e

NOX emissions were significantly related to cetane
number and aromatics. An increase of 10 in cetane number
reduces NOX emissions by 0.131 g/hp-hr. it was also predicated that a 10% decrease in aromatics will reduce
NOX level by 0.052 g/hp-hr.

P a r t i c u l a t e M a t t e r

PM emissions were highly affected by aromatics in the
fuel. A decrease of 10% in aromatics gave 0.004 g/hp-hr reductions in PM levels. Increasing Oxygen in diesel furl to
2% reduced PM by 0.009 g/hp-hr.
Tamanouchi et al. conducted experiments on similar
lines and found a relationship between fuel properties and
exhaust emissions. Their findings are shown in fig 2.9,
which shows effect of cetane number on exhaust emissions
[3].

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International Journal of Scientific & Engineering Research Volume 3, Issue 1, January-2012 2

ISSN 2229-5518

F i g . 1 . 1 ( A ) E f f e c t o f C e t a n e N u m b e r o n

E x h a u s t E m i s s i o n s [ 3 ]

F i g . 1 . 1 ( B ) E f f e c t o f A r o m a t i c C o n t e n t o n

E x h a u s t E m i s s i o n s [ 3 ]

F i g . 1 . 1 ( C ) E f f e c t o f D e n s i t y o n E x h a u s t

E m i s s i o n s [ 3 ]

As CNSL is fuel with high aromatic content, high density, and a lower cetane number can be expected. Following conclusions can be made from the above results:
 H i g h H C e m i s s i o n i s e x p e c t e d f r o m
C N S L
 V e r y h i g h N O X e m i s s i o n s a r e e x p e c t e d
f r o m t h i s f u e l .
 N o t h i n g c a n b e s a i d f o r s u r e a b o u t C O
e m i s s i o n s .
 P M e m i s s i o n s a r e e x p e c t e d v e r y h i g h .

1 . 1 ( 2 ) S u g g e s t i o n s f o r R e d u c i n g E x h a u s t

E m i s s i o n s

In the last section it became evident that if CNSL has to
be used as an alternative to diesel fuel then some
techniques of reducing emissions will have to be used. Caused by the tightening of regulation on diesel emission
around the world, engine and fuel technology for reducing emissions is also progressing. Following are some suggestions, which are found in literature for reducing emissions and improving working of engine.

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International Journal of Scientific & Engineering Research Volume 3, Issue 1, January-2012 3

ISSN 2229-5518

1) F u e l A d d i t i v e s

In petroleum industry, it is a common practice to use
cetane improvers to enhance the cetane number of the
commercial diesel fuel. The addition of cetane improvers
does not change other fuel properties much since its
concentration is usually low. The cetane improvers enhance
the ignition quality by generating a radical pool at a lower
temperature than the component in the base fuel. Compared with other processing methods, the addition of
cetane improver is a cost effective way for the refineries to produce diesel fuel with feedstock of low cetane rating [4]. A study for investigating cetane response of such cetane improves was conducted by sobotowaski. Cetane response is defined as the relationship between cetane number of the fuel and concentration of cetane improver. But no correlation was found to accurately characterize the response of fuels used in this study [5]. Li et al. conducted experiments on a single cylinder DI engine and two kinds of cetane improvers were used, nitrate-type additive and peroxide-type additive. The objective of his study was to compare the emission impact of both types of cetane improvers. Nandi et al. conducted similar experiment on these cetane improvers and come out with similar results. They found HC, CO, NOX and PM emissions were reduced significantly by treating fuels with either cetane improver. Similar reductions in NOX emissions were observed indicating that nitrogen introduced by the nitrate type cetane improver into fuel does not contribute to NOX formation. They also found that commercially used 2- ethylhexyl nitrate and di-t-butyl peroxide are mutually compatible i.e. mixing of fuels containing will not have negative effect on cetane number and engine emissions [4,6].

2) O x i d a t i o n C a t a l y s t

It has been found in literature that use of oxidation
catalyst enables HC, CO, and PM levels to be reduced. In
addition, the effect is not sensitive to fuel used. It was also observed that blending of oxygen-containing fuel enchases
the effect of the oxidation catalyst [3]. Results have shown that use of oxidation catalyst is more effective in reducing exhaust emissions than fuel modification.

3) H i g h P r e s s u r e I n j e c t i o n

It has been found by Tamanouchi et al. that use of high-
pressure injection is very effective in reducing PM
emissions and NOX emissions.

4) P a r t i c u l a r T r a p s

Particulate traps have evolved as a novel means of
reducing PM in the exhaust gas. A great variety of fitter materials are being investigated like wire mesh tubes of
Layered ceramic fibers, ceramic foam, cross-flow ceramic filters, honeycomb ceramic filters and others. The biggest problem with particulate trap is the regeneration of the fibers [7].

References:

[1] Ullman, T. L., Spreen, K. B. and Mason, R. L., 1994 “effect of cetane number , cetane improver, aromatics and oxygenentes on 1994 heavy duty diesel engine emissions”, SAE 941020
[2] Spreen, K. B., Ullman, T. L., and Mason, R. L., 1995 “Effect of cetane number, aromatics and oxygenenates on emissions from a 1994 heavy duty diesel engine with exhaust catalyst”, SAE 950250
[3] Tamanouchi, M., Morishisa, H., Shigehisa, Y., Jihei L., Takanobu, S. and Harufusa S., 1997, “Effect of fuel properties on diesel engines with and without oxidation catalyst and high pressure injection”, SAE 970758
[4] Li., X., Wallace L. C. and Gulder, O. L., 1997, “Effect of cetane enchancing additives and ignition quality on diesel engine emissions”, SAE 972968
[5] Sobotowaski, R. A., 1995, “Investigation of cetane
response of U.S. diesel fuels”, SAE 950249
[6] Nandi M. K., David C .J., Frank J. L. and Kesling H.S.-1994, “The Preformance of a peroxide based cetane improvement additive in different diesel fuel”, SAE 942019
[7] Murayama, T., 1992, “simultaneous reduction of NOX and smoke of diesel engines without sacrificing thermal efficiency”, JSME vol. 37

Prof.Paresh Kasundra is currently working as a Asst.Prof in B.H. Gardi college of engineering & technology, Rajkot

.E mail: er_paresh_kasundra@yahoo.co.in.

Co-Author Dr.Ashich Gohil is currently working as a Associate Professor

& Head, Production engineering department, L.E.College, morbid.

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