STATEMENT OF INVENTION:
Waste automobile tyres are pyrolysed at a temperature range of 450-600°C in an oxygen free
reactor to get three value added products namely pyrolytic oil, pyrogas and carbon black(CB).
Pyrolytic oil and pyrogas are used as primary or secondary fuels while the CB is disposed a solid
waste. The percentage of the CB obtained in the pyrolysis reactor is in the range of 40-45%. The
present invention describes a process of producing a synthetic fuel from CB that is obtained from
tyre pyrolysis unit. Four processes are followed to mix the carbon black and conventional diesel
fuel to get a synthetic fuel herein referred as Carbodiesel. The present invention also proposes
four different percentages of Carbodiesels were used as an alternative fuel in a low compression
ratio diesel engine.
BACKGROUND OF INVENTION:
Petroleum fuels from crude oil are used in heat and power applications. However, the
consumption of petroleum fuels results in increased environmental pollution. One of the
important threats faced by the world today is the pollutants and the greenhouse gases (GHG)
emitted by the combustion of fuel. The GHG is mostly produced from automobile vehicles,
electric power generation units and industries. The GHGs include carbon dioxide, methane,
oxides of nitrogen, carbon monoxide and water vapour. The GHGs cause global warming and
ozone depletion. The carbon dioxide emission is expected to continue to increase by about 1.9%
annually. The emission is expected to increase further in developing countries like China and
India. The emissions released from these countries are expected to increase above the world
average by the end of the year 2025, and are likely to exceed the emissions of developed.
countries by the year 2018.
The fuel prices also steeply increase as a result of the decrease in the availability of oil reserves
and increase in consumption of petroleum fuels. In order to meet the shortage of petroleum fuels,
it was proposed in the late 1980's to introduce alternative fuels, which could be derived from
either renewable or non-conventional energy sources.
Liquid alternative fuels are safer to handle and store, in comparison with gaseous fuels when
they are used in IC engines. Biodiesel and alcohol fuels derived from biomass replace the
petroleum fuels to some extent. Yet, there is a lot of scope for inventing different alternative
energy sources.
Organic matter is present in a considerable quantity in the form of industrial, municipal and food
wastes. Some examples of industrial waste are plastics, rubber, polymers, oil and cotton wastes.
Municipal wastes include biomass, waste tyres, and glass bottles, metals and non- combustibles.
Some of the selected hydrocarbons from these wastes can be converted in to useful energy, by
appropriate methods like catalytic cracking, pyrolysis, gasification etc. Greater GHG emission
reduction can be achieved when solid wastes are processed or recycled to replace the existing
fossil fuels.
Among the industrial and municipal wastes, waste tyres and plastics are available in large
quantities in comparison with other wastes. Recently, many pyrolysis plants have come up across
the world for tyre recycling. In the pyrolysis process, when the waste tyres are heated up in an
oxygen free environment and the evolving vapours are condensed then three value added
products are obtained which are (i) pyrolytic oil (ii) pyrogas and (iii) carbon black. In practice,
pyrolysis of scrap tyres in the pyrolysis plant produces four products: tyre pyrolysis oil (TPO),
carbon black (CB), pyrogas and steel wire. While TPO is used as a substitute fuel in furnaces and
burners, pyrogas is used as a secondary fuel in the pyrolysis reactor itself. CB is in disposable
and dumped in large quantities in the plant sites, causing environmental pollution. Unfortunately,
this CB can neither be converted into activated carbon (99.9 % purity) nor used in any of the
industrial applications. It is possible to produce a synthetic alternative fuel from carbonaceous
solid waste that can replace petroleum fuels to some extent. Few inventions or research include
synthetic fuel from char and coal water slurry. So far, the synthetic fuels produced by different
feed stocks have been invented by some of the inventors. They have not used the CB as one of
the raw materials for the synthetic fuel production. The CB obtained from the pyrolysis of waste
tyres, was not proposed as a raw material for synthetic fuel production by any of the inventors.
OBJECTIVE OF THE INVENTION:
The main objective of this invention is to produce a synthetic fuel from the carbon black
obtained from industries. Particularly, the CB obtained as one of the products from the recycling
of waste automobile tyres by the pyrolysis process, is used for synthetic fuel production. The
said synthetic fuel is produced by following a sequence of processes. Also, the said synthetic
fuel is proposed as an alternative fuel in compression ignition engines (diesel engines).
SUMMARY OF INVENTION
The CB obtained as the solid waste from the tyre pyrolysis plants was collected and the foreign
particles were separated and purified. The CB was then ground to fine powder with the help of a
grinding mill. The CB powder at different percentages varying from 5-20% at 5% regular
interval was taken as four samples. The average particle diameter of the CB power is in the range
of 400 and 450jlm. The samples were mixed with four different percentages of heated diesel fuel
varying from 80-95% to get four synthetic fuels namely Carbodiesel5, Carbodiesell 0,
Carbodiese115 ad Carbodiesel20. The numeric value after Carbodiesel refers the percentage of
carbon black in the Carbodiesel. The diesel fuel is heated in a temperature range of 300-400°C.
The Carbodiesel mixture is filtered to remove denser particles that are present in the mixture.
The fuel composition of the four Carbodiesels is as follows;
5% CB and 95% diesel on a volume basis and the synthetic fuel mixture was named as
Carbodiesel5.
10% CB and 90% diesel on volume basis and the synthetic fuel mixturewas named as
Carbodiesel10
15% CB and 85% diesel on volume basis and the synthetic fuel mixturewas named as
Carbodiese1l5.
20% CB and 80% diesel on volume basis and the synthetic fuel mixture was named as
Carbodiesel20.
The chemical composition of the above said Carbodiesels (Carbodiesel5 to Carbodiesel20) are
compared with diesel and given in Table 1. The physical properties of Carbodiesels are given in
Table 2.
Table 1 Comparison of chemical composition of Carbodiesel with diesel
SI.No Synthetic fuel C% H% N% S%
type
1. Carbodiesel5 68.9 9.9 9.5 6.2
2. Carbodiesell0 64.2 8.4 7.2 6.4
3. Carbodiesel15 66.7 8.9 7.8 6.5
4. Carbodiesel20 68.2 9.2 7.5 6.8
5. Diesel 67.8 8.4 8.2 5.2
Table 2 Properties of Carbodiesels
Properties Carbodiesel5 Carbodiesell 0 Carbodiese115 Carbodiese120
Density gm/cc 0.8335 0.8330 0.8392 0.8410
Viscosity, cSt 3.07 3.08 2.79 2.76
Ash content, % 0.004 0.008 0.008 0.004
Carbon Residues, % 0.08 0.14 0.11 0.08
Flash point,OC 680 660C 580 600
Fire Point, °C 780 760C 680 700
Pour point, °C Below minus Below minus 12 Below minus 12 Below minus 12
12
C.V. KJlkg 42727 42975 44888 43912
DETAILED DESCRIPTION
The above said synthetic fuels (Carbodiesels) were tested in a compression ignition engine
having a compression ratio of 17.5.The engine was subjected to different load conditions for
Carbodiesel5, CarbodiesellO, Carbodiesell5 and Carbodiesel20. The test engine for this
invention is a single cylinder, four stroke, direct injection, diesel engine. With a bore of 87.5mm
and stroke of 10mm the engine has a maximum power output of 4.4 kW and 1500 rpm. The
injection timing of the fuel injected was set at 23° before TOC, and the injection pressure was
200 bar. The engine was coupled to an electrical dynamometer, to provide a brake load. The
engine load was monitored by the control panel. The synthetic fuel was injected by the existing
injector of the system, an air box was provided on the suction side of the air. An AVL 444
exhaust gas analyser was used to measure the carbon monoxide (CO), unburnt hydrocarbon
(HC), and (nitric oxide) NO in the engine exhaust. An AVL437 diesel smoke meter was used to
measure the smoke in the engine exhaust. The arrangement of the experimental setup is shown in
Fig 1.
This perhaps fulfills the objective of the invention that is to provide an alternative fuel which can
replace the diesel fuel, and also, to minimize the CB which is disposed in tyre recycling
industries. The transport and storage of the said synthetic fuels (Carbodiesel) poses no problems
or difficulties, as it is a liquid fuel.
In the first embodiment of the invention, the said synthetic fuel is one which is totally composed
of carbon black and diesel fuel. In the said fuel, at least one constituent is a selected hydrocarbon
in the carbon black. Even if the proportion of the said synthetic fuel varies from 5% volume to
20% volume, the density does not increase beyond 0.85, which is less than the ASTM standard.
ENGINE PERFORMANCE
Brake Thermal Efficiency (BTE)
Fig.1 shows the variation in the brake thermal efficiency with brake power for four Carbodiesels
compared with diesel. It is seen that Carbodiesel5 and Carbodiesell 0 exhibit higher brake
thermal efficiency (BTE) at full load, compared to diesel, Carbodiesell5 and Carbodiesel20.
This is because of the additional lubricity offered by the fuel, as a result of higher viscosity and
sulphur present in Carbodiesel5 and CarbodiesellO. For Carbodiesell5 and Carbodiesel20, the
thermal efficiency is found to be lower, because the density and viscosity are higher than that of
diesel, Carbodiesel5 and Carbodiesell O. The values of BTE for diesel Carbodiesel5,
CarbodiesellO, Carbodiese1l5, and Carbodiesel20 are 27.7, 28.62, 26.48, 21.11, and 23.50%
respectively, at full load.
Brake specific energy consumption (BSEC)
Fig.2 depicts the trend of brake specific energy consumption (BSEC) with brake power for diesel
and the different Carbodiesels. The BSEC of Carbodiesel15 and Carbodiesel20 show higher
values than that of diesel, Carbodiesel5 and Carbodiesell O. The higher viscosity and poor
volatility are the reasons for the higher BSEC ofCarbodiesel15 and Carbodiesel20.
EMISSION ANALYSIS
Carbon monoxide (CO) emission
Fig.3 shows the variation of CO emission with brake power for the Carbodiesel blends, and
compared with diesel. It is seen that the CO emission is the highest in the case of Carbodiesel20.
As the Carbon black percentage increases the CO emission increases, as a result of poor mixture
formation. However, the values of CO for all the Carbodiesel blends are lesser then 0.1%, which
is acceptable limit.
Nitric oxide (NO) emission
Fig.4 depicts the nitric oxide (NO) emission corresponding to the different brake power values
for the Carbodiesel, the compared with diesel. It is found that Carbodiesell0 shows the lowest
value among the diesel and Carbodiesel. This is probably due to the lower heat released due to
inferior combustion.
Hydrocarbon (He) emission
Fig.5 shows the variation of the hydrocarbon emission for the Carbodiesels, compared with
diesel. It is seen that Carbodiesel20 is the highest followed by Carbodiese1l5 at full load. This is
due to the poor atomization of high density fuel that results in a more incomplete combustion.
Carbodiesel5 is the lowest among the other Carbodiesels, but a little higher than diesel at full
load.
Smoke emission
Fig.6 illustrates the variation of smoke emission with respect to brake power for diesel and the
Carbodiesel. The smoke emission is the lowest for diesel, as a result of better fuel preparation
and combustion. Among the Carbodiesel mixtures, Carbodiesel20 shows the highest smoke
value at full load, followed by Carbodiese1l5, CarbodiesellO and Carbodiesel5, at full load.
By analyzing the above figures, some examples are given with respect to the use of Carbodiesel
as an alternative fuel in diesel engines.
Example 1:
Engine performance and emission analysis of Carbodiesel5 at 3.5kW(75% load) gives 30.34%
brake thermal efficiency,11.861MJlkWh as brake specific energy consumption, while it produces
the emission of nitric oxide 482 ppm ,CO 0.02% by volume,HC 9 ppm in the engine exhaust.
Example 2:
Engine performance and emission analysis ofCarbodiesellO at 4.4kW(100% load) gives 26.48%
brake thermal efficiency, 13.59MJlkWh as brake specific energy consumption, while it produces
the emission of nitric oxide 630 ppm ,CO 0.04% by volume,HC 11 ppm in the engine exhaust.
Example 3:
Engine performance and emission analysis of Carbodiese1l5 at 4.4kW(l00% load) gives 21.11 %
brake thermal efficiency, 17.05 MJlkWh as brake specific energy consumption, while it produces
the emission of nitric oxide 750 ppm ,CO 0.05% by volume, and HC 14 ppm in the engine
exhaust.
Example 4:
Engine performance and emission analysis of Carbodiesel5 at 2.3kW(50% load) gives25.88%
brake thermal efficiency, 13.90 MJlkWh as brake specific energy consumption, while it produces
the emission of nitric oxide 343 ppm ,CO emission 0.02% by volume, and HC 4 ppm in the
engine exhaust.
Example 5:
Engine performance and emission analysis of Carbodiese120 at 4.4kW(100% load) gives 23.5%
brake thermal efficiency, 15.31 MJlkWh as brake specific energy consumption, while it produces
the emission of nitric oxide 650 ppm ,CO 0.07% by volume, and HC 14 ppm in the engine
exhaust.
Example 6:
Engine performance and emission analysis of Carbodiesel5 at 4.4kW(100% load) gives28.62%
brake thermal efficiency,12.57MJlkWh as brake specific energy consumption, while it produces
the emission of nitric oxide 640 ppm ,CO 0.04% by volume, and HC 12 ppm in the engine
exhaust.
CLAIMS:
We claim that:
1. A process of producing a synthetic fuel named, as Carbodiesel is obtained by mixing carbon
black(CB) with diesel on volume basis.
2. A process according to claim 1, wherein the CB is dried, powdered, mixed with diesel whose
temperature in the range of 300-350°C and the mixture is filtered to get the Carbodiesel..
3. A process according to claim 1, wherein the CB is obtained in a tyre pyrolysis plant, whose
chemical composition is as follows; carbon content between 81 - 84.4 wt %and hydrogen 2 -
2.86 wt %, nitrogen content 0.1 - 0.3 wt %and sulphur content 1.5 - 2.4 wt %, ash content of
10.24 - 12 wt % and oxygen content 0.5 - 1 wt %.
4. The Carbodiesel as claimed in claim 2, the maximum ratio of carbon black in the Carbodiesel
usable in a direct injection (DI) engine, without any engine modification, is in the range of
5%-20% carbon black and the rest is commercial diesel.
5. The process of producing the synthetic fuel namely Carbodiesel according to claim 1,
produced by mixing CB with diesel can be used as an alternative fuel in DI diesel engine
substantially, as herein described with reference to the accompanying drawings.