P V Rao

Biodiesel is becoming prominent among the alternatives to conventional petro-diesel due to economic, environmental and social factors. The quality of biodiesel is influenced by the nature of feedstock and the production processes employed. The process of transesterification is affected by the molar ratio of alcohol to oil, amount and nature of catalysts (NaOH and KOH), reaction time, and temperature. Jatropha methyl ester was analyzed for qualitative and quantitative characterization by using GC-MS and FT-IR techniques. C H N O S was analyzed using elemental analysis. Its fuel properties like cetane number (ignition quality indicator), iodine value (unsaturation levels), molecular weight, density, kinematic viscosity, heating value, flash point etc., is also calculated it is concluded that the biodiesel from these species can be feasible, cost effective and environment friendly

Furnace oil is atomized with air in the burner and fired, which produces hot flue gases that pass into the boiler tubes to generate steam. The furnace oil fired boilers contribute to green house gas emissions and secondary pollutants. Briquette as a fuel to address these problems is a better alternative. This work deals with the fuel system conversion of an existing fire tube boiler running with furnace oil to saw dust briquettes. Further the boiler capacity is increased by mounting a water wall assembly. The efficiency of this combined fire tube and water tube boiler is determined by using indirect method approach also called as heat-loss method as per Indian Standard for boiler efficiency testing IS-8753 as well as by American Society of Mechanical Engineers, Power Test Code ASME PTC 4.1. The emission measurements are carried out by portable flue gas analyzer. The efficiency of boiler when fired with briquettes is found lower than that when fired with furnace oil. A significant reduction in the operating cost of boiler is achieved by fuel conversion technology. The emissions of furnace oil boiler are compared with that of briquette boiler. The sulphur oxides (SO x), nitrogen oxides (NO x), carbon dioxide (CO 2) emission levels are low while firing briquettes. Carbon monoxide (CO) emission level due to incomplete combustion of fuel is more when firing briquettes. This conversion of fuel system utilizing briquettes in boiler offers many economical, social and environmental benefits.

The purpose of this study is to examine the influence of
biodiesel (BD) fuel properties on different characteristics of
the engine and to compare with the baseline petroleum diesel
(PD) fuel. This study consists of two parts, first one is
biodiesel characterization and the second one is testing in the
engine. Two BD fuels namely, the medium chain (C6-C24)
coconut oil methyl ester (COME) and the long chain (C16-C18)
sesame seed oil methyl ester (SSME) were selected. It is
observed that, the physical and chemical properties such as
viscosity, density, bulk modulus, calorific value, C/H ratio,
and iodine value of SSME are higher than that of COME,
while the cetane number, saturation% and oxygen% of the
COME is higher than that of SSME. Experiments were
conducted in a naturally aspirated, single cylinder, four-stroke,
stationary, water cooled, constant rpm (1500), in-line (pumphigh
pressure tube-fuel injector) direct injection compression
ignition (DI-CI) engine with COME, SSME (with and without
preheating), and PD as fuels. The performance was evaluated
in terms of fuel consumption (FC), brake specific energy
consumption (BSEC), and thermal efficiency (BTE). Except
for COME at full load, the BTE of the esters over all load
ranges were less than that of PD fuel. Also, a significant
improvement in BTE was observed, when the SSME is tested
at PD’s viscosity by using preheating technique. At full load,
the BSFC of COME and SSME are increased by 16.61% and
18.24% respectively. The minimum BSEC (at full load) of
COME is decreased by 1.3% and while that of SSME is
increased by 4.5%, as compared to that of PD fuel. The full
load peak pressures for COME, SSME and PD fuel are 63.8
bar, 65.8 bar, and 62.9 bar respectively. The high peak
pressures of the methyl esters are probably due to dynamic
injection advance, caused by their higher bulk modulus. The
net heat release rate (HRR) and cumulative heat release (CHR)
were calculated from the acquired data. The results show that,
at all loads there is a slight increase in peak HRR for COME
and large increase in peak HRR for SSME against PD fuel.
The higher values of peak HRR indicate better premixed
combustion with the methyl esters. However, the peak HRR
for preheated SSME (SSME_H) decreases due to late injection
and faster evaporation of the fuel. It was observed that, at full
load the nitric oxide (NO) emission of SSME is increased by
12.9 %, while that of COME is decreased by 13.8% as
compared to that of PD fuel. The smoke is increasing linearly
with the fuels ‘C/H’ ratio regardless of their molecular
structure. The HC emissions of both the esters are very low
and are reduced by up to 73%, as compared PD. Also, there is
a significant reduction in all exhaust emissions, and in
particular the NO emission is observed with preheated SSME,
due to change in premixed combustion phase.

The aim of this work is to study the effect of properties of Karanja (Pongamia pinnata) methyl ester on
combustion, and NOx (oxides of nitrogen) emissions of a diesel engine. The properties of the karanja
methyl ester such as viscosity, density, bulk modulus, calorific value, iodine value, cetane number,
saturation% and oxygen% are considered for this study. Experiments were conducted in a naturally
aspirated, single cylinder, four-stroke, stationary, water cooled, constant rpm, in-line (fuel pumppressure
tube-fuel injector) direct injection diesel engine. The engine tests were conducted with karanja
methyl ester (with and without preheating), and baseline fossil diesel. The peak pressures and peak
heat release rates for methyl ester was slightly higher than diesel fuel. The crank angles for peak
pressure of the karanja methyl ester are very close to top dead center. This is probably due to dynamic
injection advance caused by their higher bulk modulus. However, the peak cylinder pressures for
preheated methyl ester decreases, due to late injection and faster evaporation of the fuel. It was
observed that, at full load the oxides of nitrogen emissions of karanja methyl ester are increased by 6%.
A significant reduction in oxides of nitrogen emission is observed with preheated methyl ester

The aim of this work is to study the influence of biodiesel key properties such as bulk modulus, density, fatty acid composition, cetane number, calorific value, % oxygen, C/H ratio, viscosity, and temperature on the injection, combustion and emission characteristics of a direct injection compression ignition (DI-CI) engine with in-line fuel injection system. Experiments were conducted on a four-stroke, water-cooled, constant speed, DI-CI engine with rice bran oil methyl ester, sesame seed oil methyl ester, and baseline petroleum diesel as fuels. it is observed that, the  biodiesel peak pressures, premixed combustion, and NOx emissions are higher than that of diesel fuel. When the biodiesels are injected at diesel viscosity (by preheating), the NOx levels are reduced. It was concluded that, the reduction of bulk modulus of biodiesel due to preheating is responsible for injection timing retard, and lower NOx emissions.

The purpose of this study is to examine the influence of key properties of pongamia biodiesel on engine performance, combustion, and emission characteristics of direct injection diesel engine. The key properties of the pongamia biodiesel such as viscosity, density, bulk modulus, calorific value, iodine value, cetane number, saturation% and oxygen% are considered for this study. Experiments were conducted in a naturally aspirated, single cylinder, four-stroke, stationary, water cooled, constant rpm, in-line (pump-high pressure tube-fuel injector) direct injection diesel engine with pongamia biodiesel (with and without preheating), and petroleum diesel as fuels. The performance was evaluated in terms of fuel consumption, brake specific energy consumption, and thermal efficiency. A significant improvement in thermal efficiency was observed with preheated biodiesel. The peak pressures and peak heat release rates for biodiesel was slightly higher than diesel fuel. The high peak pressures of the biodiesel are probably due to dynamic injection advance caused by its higher bulk modulus. The higher values of peak heat release rates indicate better premixed combustion with the biodiesel. However, the peak pressures for preheated biodiesel decreases due to late injection and faster evaporation of the fuel. It was observed that at full load the nitric oxide emission of biodiesel is increased by 6 %. The hydrocarbon emissions of the biodiesel are very low and are reduced up to 32 % as compared to that of diesel fuel. There is a significant reduction in all exhaust gaseous emissions. Also a considerable reduction in nitric oxide emission is observed with preheated biodiesel due to change in premixed combustion phase. However when the preheated biodiesel is used, the smoke emission was increased due to prolonged combustion (diffusion) at lower viscosity. A considerable reduction in carbon monoxide emission as also observed with the preheated biodiesel.

The aim of the present research work is to investigate
the influence of Jatropha biodiesel properties on various
characteristics of a direct injection compression ignition engine. The
experiments were performed at different engine operating regimes
with the injection timing prescribed by the engine manufacturer for
diesel fuel. The engine characteristics with Jatropha biodiesel were
compared against those obtained using diesel fuel. From the
results, it is observed that the biodiesel performance and emissions
are lower than that of diesel fuel. However, the NOx emission of
Jatropha biodiesel is more than that of diesel fuel. These high NOx
emissions are due to the presence of unsaturated fatty acids and the
advanced injection caused by the higher bulk modulus (or density)
of Jatropha biodiesel
Furthermore, the possibility for reduction of NOx emissions
without expensive engine modifications (hardware) was investigated.
Keeping this in mind, the Jatropha biodiesel was preheated. The
experimental results show that the retarded injection timing is
necessary when using Jatropha biodiesel in order to reduce NOx
emission without worsening other engine characteristics. Results
also indicate improved performance with the application of
preheated biodiesel. The only penalty for using preheated biodiesel
is the increase of smoke (soot).

The aim of this work is to investigate the effect fuel properties on combustion and emission characteristics of the direct injection (DI) diesel engine running with biodiesel (BD) fuel and to compare with those of petroleum diesel (PD) fuel. The rice bran oil was chosen and this oil is transesterified in to methyl ester. The physical, chemical and thermodynamic properties of the fuel such as viscosity, density, bulk modulus, flash and fire points, cloud and pour points, oxygen %, calorific value,  C/H ratio, carbon chain length, molecular weight, saturation %, iodine value, and the cetane number of the rice bran oil methyl ester (ROME) was characterized as per ASTM norms and found comparable to PD fuel. Experiments are conducted in a single cylinder, 3.72 kW, constant speed (1500 rpm), water cooled, DI diesel engine equipped with in-line fuel injection system, and fueled with ROME and baseline PD. The engine is also tested with preheated (at 60 0C) ROME (ROME_H) to maintain the same spray characteristics of PD fuel. It was observed that, the crank angle position of peak cylinder pressures for ROME was shifted towards top dead center, and the peak pressures were increased due to advanced dynamic injection timing, probably caused by its higher bulk modulus. Heat release analysis based on single-zone model has been evaluated from the acquired data. The results shows that,  both the fuels exhibited similar combustion stages; however ROME showed earlier start of combustion and higher heat release during premixed combustion phase at all engine loads. The intensity of premixed combustion is decreased and diffused combustion is increased with preheated ROME. The gaseous emissions such as oxides of nitrogen (NOx), total hydrocarbons (HC), carbon monoxide (CO), and smoke under different load conditions were measured. Dramatically, lower HC emissions were found with the ROME fueled engine and at full load, the HC’s are reduced by 28%. The HC emissions are further reduced with preheated ROME. It is also observed that, the NOx emissions of ROME fueled engine shows higher concentrations, when compared to PD fuel, for the same static injection timing. When the engine is running with preheated ROME, the NOx emissions are decreased and at full load NOx levels are lower than PD fuel. At full load, there is a substantial reduction in the smoke emission was observed and the reduction was attributed to its lower ‘C/H’ ratio, and oxygen present in the ROME. However, when the preheated ester is used, the smoke emission was increased due to prolonged combustion (diffusion) at lower viscosity. There a significant reduction in CO emissions was observed with the preheated ROME

The problem of high viscosity of vegetable oils has been
approached in several ways, such as esterification, preheating,
and blending or dilution with diesel fuel. In this paper the oil
that is preheated and tested on the engine is Pongam Methyl
Ester (PME). In spite of the esterification process, the
viscosity (5.9 cSt) of PME remains high compared to the
viscosity (3.1 cSt) of diesel fuel at room temperature of 30o C.
To eliminate the fuel injection problems due to its higher
viscosity, the PME is heated to 52oC to meet the viscosity of
diesel fuel. Neat PME (B100) and neat preheated PME (PME
52) are tested in a laboratory based DI diesel engine replacing
the conventional diesel fuel. The engine is tested with PME
and PME 52 to verify the change in performance and the
exhaust emission aspects at the selected loads (0, 1/4, 1/2, 3/4,
and Full) and the results are compared with the base line diesel
fuel. It is observed that there is marginal improvement in the
performance and the emissions in case of PME 52. The
vibration spectrum of the engine cylinder head is studied to
investigate the knocking and the detonating characteristics of
the engine at all loads. SFC decreased considerably and
thermal efficiency has increased with PME 52. Emissions of
CO increased and NO decreased in both the cases of PME and
more in the case of PME 52. No knock/detonation is observed
in the frequency plots recorded on the cylinder head. The
heating is conducted in the fuel line close proximate to the
injector with a 50 W heating element with a programmable
temperature controller. This heating element is the only
retrofit element introduced without any major engine
modification.
1 Introduction

In this paper, Mahua Methyl Ester (MME) with water
fumigation (superheated water vapour) at the inlet of the
engine (by certain percentages of the injected ester) is tested in
a laboratory based DI diesel engine. The SFC for the various
percentages of water fumigation is observed to be in between
diesel which is the lowest and the neat MME which is the
highest at all loads. Brake thermal efficiency is the highest for
0.25 kg/hr water vapour at the suction. The delay period for
the diesel fuel is maximum as can be observed from the
separation of the pressure curves from the motoring curve. As
regards to the exhaust emissions are concerned, CO emissions
increased with the water fumigation. NO emissions reduced at
all percentages of the water fumigation. HC emissions
increased when compared to the diesel fuel at all loads

The problem of high viscosity of vegetable oils has been approached in several ways, such as esterification, preheating, mineralization and blending or dilution with diesel fuel. In this work, the non edible oil like Mahua (Madhuka Indica) is esterified and its viscosity is brought down to 6 cSt. Nevertheless, the viscosity of Mahua Methyl Ester (MME) remains high compared to the viscosity of diesel fuel (3.1 cSt) at room temperature of 30o C. To eliminate the fuel injection problems and encourage atomisation, the MME is heated to 55oC to meet the viscosity of diesel fuel. Neat MME (B100) and neat preheated MME (MME 55) are tested in a laboratory based DI diesel engine replacing the conventional diesel fuel. The engine is tested with MME and MME 55 to verify the change in performance , the exhaust emission aspects and engine vibration  at the selected loads (0, 1/4, 1/2, 3/4, and Full) and the results are compared with the base line diesel fuel to verify the feasibility of replacement. Pressure crank angle history envisages reduction in ignition delay in the case of diesel fuel and the esters. Pre-heating of the ester didn’t change the delay any further. Thermal efficiency and specific fuel consumption recovered after preheating when originally there is 5% reduction in the absolute value at full load between the diesel and the neat unheated Mahua methyl ester. 2.3% absolute value recovery is observed after preheating. SFC reduced by 0.04% in absolute value after preheating at full load which is maximum and varied betterment is observed at all loads. There is remarkable reduction in the Hydrocarbon emission in the exhaust gas with the implementation of unheated methyl ester and preheating further decreased this emission. CO emission is higher after ester usage and preheating reduced CO levels at all loads. CO2 levels have increased with the application of Biodiesel and preheating reduced this emission marginally at higher loads. NO and smoke decreased and preheating marginally decreased these emissions further at all loads. There is no abnormal amplitude rise at higher frequencies (between 3000 Hz to 25000 Hz) and hence indicating absence of knocking of the engine with the usage of Biodiesel and preheated Biodiesel. There is better cumulative heat release with the application of Biodiesel and preheating doesn’t bring about any significant change in this parameter.

Neat vegetable oil possesses higher viscosity and direct usage of the oil in the diesel engine causes injection problems and fuel atomisation problems. In such case engine needs modification in the aspect increasing compression ratio. The neat vegetable oil is subjected to esterification which reduces viscosity. Not with standing, the viscosity of the sesame seed methyl ester (SSME) remains higher (5.2 cSt) than that of diesel’s (2.75 cSt) at room temperature 30oC. To maintain the same injection-spray characteristics, the SSME is pre-heated to 54 0C (SSME 54) to meet the diesel fuel viscosity and injected into DI diesel engine. The engine is tested at the selected loads (0, 1/4, 1/2, 3/4, and Full) and performance and exhaust pollution results of unheated and heated esters are compared with the baseline diesel fuel. The Engine performance (BTE, and SFC), Combustion        (Net and Cumulative heat release rates), Exhaust emissions (HC, NO, CO, CO2, and Smoke) and cylinder head vibration (FFT and Time wave forms) are studied and the average cylinder head vibration is presented to compare engine behaviour.

It is observed that there is 3% absolute decrease in brake thermal efficiency when unheated SSME is used. When the oil is preheated to 540C there is a recovery of 2%. Heat release is faster when the oil is heated. The cumulative heat release history tells that better diffused combustion is observed when heated SSME is implemented. There is rise of 0.04Kg/ kW-hr in SFC when unheated ester is implemented in comparison to the petroleum diesel. This is because of lower heat value of the ester. Specific fuel consumption has decreased by 0.02Kg/kW-hr in absolute terms when oil heated. There is clear 50% HC reduction when the unheated ester is used and a further drop of 20ppm is recorded when the ester is heated. There is rise in CO level when diesel is replaced by unheated SSME and the heated oil reduce the CO levels lower than that when diesel is used. Better reductions have been observed in case of NO and CO2 when the ester is heated. Smoke emission has increased marginally in case of heated ester when compared to unheated ester. There is relief in cylinder vibration when the heated oil is implemented.