Title of the Invention
A novel pellet fuel and a process for the preparation thereof
FIELD OF THE INVENTION
The present invention relates to a novel pellet fuel. More particularly, the present invention provides
pellet fuel with a high calorific value using tannery wastes. Further, the invention provides a process
for producing the said fuel. The invention is envisaged to have enormous application in fuel
industries as a source of energy. The product of the invention is envisaged to be a substitute for all
conventional fuels. The invention provides an option to utilize the collagenous wastes generated by
the leather processing industry for making a source of energy in the form of pellet fuel.
BACKGROUND OF THE INVENTION
One of the largest problems faced by tanneries and by society in general is the increase in the
amount of hazardous and polluting solid waste and other wastes generated every year. Leather
industry is one of the fourth largest earners of the country and contributing around 6 % of total
export income. More than 1500 tanneries in India generate about 200 tons of solid wastes every day
and contaminate the environment and the ground water in many places. New arrangements have
been made for waste management in order to manage the said amount of solid waste that is produced
every year. This management replaces traditional methods like open dumping, landfills and
composting.
On the other way, these said hazardous polluting solid waste can be converted into useful pellet fuel
to meet the energy demand in India, as well as to avoid the landfill in the open area. Ultimately, this
will protect the environment and ground water as said before.
The burning of raw hazardous tannery solid waste generates high pollutions via heavy metal
emissions, S02, NOx, CO, C02 and other dust particles. An expensive off-gas treatment mechanism
2
is needed to reduce or eliminate the emission level that meets the requirement of environmental
safety and other regulations. In addition conversion of wet hazardous tannery solid waste requires
more amount of energy than the actual energy to burn the solid waste. Nonetheless, production of
waste-derived fuel has evolved to become an acceptable approach to waste management. Various
methods are employed to convert hazardous tannery wastes into useful high yield pellet fuel as a
product with a higher calorific value and lower ash production than an incineration process.
Bruton and Laramie reported(U.S. Patent 4,060,396, 1977),a simple and costeffective extrusion
machine to produce fuel log made of interlocking array withdisc shaped wafers. Each wafer consist
of compressed wood particles placed in the head of extrusion machine as a billet, they are futher
made into different forms so as to increase the ingnition rate quicker. Romell reported (U.S. Patent
6,152,973 A, 2000), a novel machine for making compressed wood pellet wafers and process to
convert it as pellet fuel. The pellets are made from each wafer hence they are smaller in size ranging
about 12-20mm diameter. The pellet prepared by this method can be easily packed and distributed to
serve the purpose for wood burners. Goldrick reported (U.S. Patent WO2009147361 Al, 2009), a
process for preparing layered rigid fuel pellet using biomassmaterial generally of biological origin, a
particulate carbon based material and a silicate based bindermixed together inagitatation at ambient
temperature to obtain the novel fuel.Drisdelle et.al reported (U.S. Patent 77853797, 2010), a method
to prepare combustible pellet comprising of agricultural fiber waste to obtained fuel having the
moisture content of 10—16%. The pellet contains chemical additives like ammonium nitrate, calcium,
aluminum, barium iron which on ignition can cause environmental pollution. The pellet formed has
ash content of 1.1% to 20%) by weight with calorific value of about 7,000 BTUs per pound of
fuel.Andrews and Michael reported (U. S. Patent 5980595, 1999), a method for manufacture of
pellet fuel comprising of coal, cellulosic material selected from waste water sludge, densified
thermoplastic material to produce an efficient industrial high heat output fuel. The pellet fuel
produced has moisture of about 10% by weight and the waste materials are burned in a pulver or
3
stoker style furnace producing heat up to 16,000 BTUs per pound.Lee et.al reported (U.S. Patent
7497392 B2, 2009), a new method for converting municipal solid waste material into fuel and an
apparatus for transforming the waste material and processing them. The time taken for the complete
process was not greater than 85minutes.The produced fuel contains55% moisture and a heat value of
2500 BTUs.
A method for bio-gasification of biomass consisting of solid/liquid animal waste, mortalities,
municipal waste and poultry waste can be used to produce an energy or combustible gas with the
help ofgasifier/fermenter as reported by Gang et.al (U.S.Patent 20080271363,2008) and Murat et.al
(U.S. Patent 0060265954, 2006).
Waste from animal confinements are dumped into large inlets which causes environmental health
hazards hence, a method of transporting these wastes and configuring them into solid and liquid
waste streamsare employed to produce useable fuel. The system consists of a moisture controller, a
processor for converting energy and a power generator configured to utilize the energy source as
reported by Schien et al (U.S.Patent7597812, 2009).Hiltunen et.al reported(U.S Patent 5,626,088,
1997),an improved method to utilize biofuel and an apparatus comprising fluidized bed gasifier, a
boiler to generate steam equipped with fossil fuel burner to produce energy. This is an alternative
method to replace fossil coal with newer fuel with decreased emission of CO2.
Nielsen reported(U.S Patent 7731856, 2010), a method for collecting the farm animal waste and
treating the waste matter to produce urea lean biogas using biogas reactor and urea rich animal
product with less nitrogen in manure, to reduce ammonia content in stables for animals. A
methodology to produce urea and urea formaldehyde was also employed as one of the product.
Funk reported (U.S. Patent 3970524, 1976), a method for treating solid waste disposed from various
industries like agriculture, municipal, poultry waste, paper and pulp industries, which can be
converted by means of partial oxidation and distillation into gas under controlled temperature and
4
pressure. The produced gas is suitable for industrial and chemical uses as main components or
selective ingredients.
Feldman reported (U.S. Patent 4005994, 1977),a process of methanogenesis and a reactor for
conversion of solid wastes into pipeline gasas an eco-friendly approach. This invention provides an
alternative synthetic gas which disposes minimum amount of ash residue at the end of the process.
The solid waste comes in contact with hydrogen gas in the reactor to form carbonaceous char, the
char reacts with steam and gaseous oxygen to produce synthetic gas in the reactor. The gas obtained
is then passed on to the methane gas production reactor and then supplied through pipelines.
Warner reported ( U.S. Patent 4852344, 1989), a method for utilization of municipal solid waste and
an apparatus to burn the collected solid waste to produce energy. The efficiency of waste disposal
was improved by combining a waste-burning apparatus with a gas turbine-generator set with exhaust
gas. A boiler associated with the waste-burning incinerator is supplied with steam to operate a steam
turbine and a second electric generator. The combustion apparatus may be employed for waste
material incineration in general, toxic waste incineration, and for smokeless burning of wood and
vegetation. Another process for treating municipal solid and sludge waste by eliminating the water in
the sludge using furnace. This is done to reduce the particle size by enriching it with oxygen as
reported by Goff et al (U.S.Patent 5405537, 1995).
Keller et.al reported (U.S. Patent 5134944, 1992), a process to utilize solid waste material by
combining with particulate carbon fuel to produce large amount of cost effective non petroleum fuels
to serve as an alternative for gasoline and diesel fuel. Thermal separation of coal-methanol
suspensions are delivered by pipeline that provides reactive carbon fuel. Methanol produced from
cleaned syngas and ethanol produced by corn fermentation is blended as gasoline or diesel fuel and
other additives are also used resulting in no solids over.
The process to extract protein hydrolysates and/or gelatins from hides/ hide processing residues,
vegetable products, byproductsare combined with polymer material to form regenerated leather or
5
fabric which can be tanned and dyed as leather. The resulting novel material can be used as leather
stucco which is having similar characteristics as leather as reported by Neresini et.al.
(U.S.Patent2001090925 Al, 2010).
To prepare composite material using post-industrial and post-consumer leather wastes comprising of
leather fibers, binding agents or additives such as synthetic latex, natural latex, PVA, starch and nonleather
fiber like cellulose combined with low density cushioning agents like foam, rubber particles
are used to soften the substrate. The material produced in such manner are known as engineered
leather substrates which can be a substituted in variety of articles during manufacture as reported by
Coulson et.al (U.S. Patent, 0070184742, 2007).
The solid and liquid wastes from different sources are dumped into large lagoons asa routine practice
which needs immediate attention to utilize the set out wastes and to produce valuable products.
Attempts are been made to convert agricultural, biological, industrial wastes to solid/liquid fuels and
pellet fuels from solid biomass are converted subsequently into energy .To reduce environmental
impact works have been carried out, some works relevant to our invention has been discussed below.
Pelletized fuel are produced from coal tailings and spent mushroom compost usable in gasifiers or
power plants as reported by Changkook Ryu et.al (Fuel Processing Technology, 89, 269-275, 2008).
Carbon granules was made into pellets and mixed with polymeric binder and chemical activator to
form a mixture. The mixture was then coated with carbon black powder to activate the pellet at a
given temperature to achieve high BET surface area and mesoporous volume. The carbon pellet
formed from cellulose binder and ZnCb activation at 600°C shows higher BET surface and larger
mesopore volume with lesser ash contentas reported by ZhongrenYueet.al (Microporous and
Mesoporous Materials 96, 314-320, 2006).
The tannery raw fleshing wastes disposed during the pre-tanning operations are rich in protein and
fat that was utilized as an oil source for transesterification reactions with good oxidation stability.
They are also useful as feedstock lubricant and as an ingredient in cosmetic industries as reported by
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Ashisler et.al (Waste Management, 25, 311-32,2010). The main objective is to quantitatively
measure the natural fat removed from hides during beam house operation and to reuse them in
fatliquoring stage. The effectiveness of absorption of fat was good as reported byLeticiaet.al (Journal
of Cleaner Production, 15, 12-16, 2007).A method to convert leather industry waste to usable
product was reported by Simeonova et.al(Waste Management 16, 765-769,1996), the process
includes washing to remove excess of salt, extract fat, collagen and protein from insoluble residue to
produce cattle tallow, collagen hydrolysate as glue/ further purification as gelatin and fodder
respectively. Production of biogas from co-digestion of leather fleshing with biodegradable
municipal wastes resulted with C:N ratio as 15 at pH 6.5 and increase yield of 6518 ml as reported
by Shanmugam et.al (Bioresource Technology 100, 4117-4120, 2009). Tannery wastes (chromiumand
vegetable tanned shavings and buffing dust) were pyrolyzed in a reactor at 450-600°C under N2
atmosphere to generate gas and oil. The carbonaceous residue yielded with calorific value ranging
4300-6000 kcal Kg "1 as reported by Yilmaz et.al (Resources, Conservation and Recycling, 49 436—
448, 2007).Pre fleshing from leather industry is converted into biodiesel as an environmental
friendly fuel as reported by Hasan Ozgunay et.al (Waste Management, 27, 1897-1901, 2007).
The limitations of the prior art are summarized below:
Environmental pollution is always been a serious threat to living beings that needs immediate
attention. The wastes disposed from leather processing industries occupies higher place due its
inappropriate management of wastes. Previously works has been carried out to utilize the solid/liquid
wastes disposed from the industries into valuable products. In present scenario leather industry
wastes are utilized and converted into products such as regenerated leathers, recovery of oil, gelatin,
glue, cattle tallow, fuel such as biogas, bio diesel, pelletized fuel are produced from various
industrial wastes using chemical binder/plasticizers which on combustion exhibits less calorific
value of fuel. There is always been a crisis for biodegradable fuel in the global market.
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§
OBJECTS OF THE INVENTION
The main objective of the present invention is to provide a novel pellet fuel, which obviates the
limitations as stated above.
Another objective of the present invention is to use collagenous substance to produce pellet fuel.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a novel pellet fuel comprising collagenous substances,
organic matter, a binder and a plasticizer, the said pellet being characterized by its density in the
range of 0.8 to 3 gm/cc, moisture content in the range of 10-15% by weight, and exhibiting emission
on combustion essentially involving 40-60 % C02>, 10-15%NO2,10-20 % VOC, 8-14% S02,the said
fuel further exhibiting a calorific value in the range of 15000-30000 kJ/Kg, the cross-section of the
pellet being substantially circular exhibiting a diameter in the range of 3-9mm, the bottom ash
generated on combustion of the pellet at a temperature in the range of 500-1500°C in air, being not
more than 10 % by weight.
Further, the present invention provides a novel pellet fuel comprising collagenous substances, organic
matter, binder and additive, the said pellet fuel has density in the range of 0.8 to 3 gm/cc and
moisture content in the range of 10-15% by weight.
In an embodiment, the cross-section of the pellet being substantially circular exhibiting a diameter in
the range of 5-15 mm.
In yet another embodiment, the collagenous substances used is selected from shaving wastes of
hides/skins, trimming wastes of hides/skins, fleshing wastes of hide/skin.
In yet another embodiment, the organic matter used is such as weeds, timber, timber dust, coir pith
dust, Calophylluminophyllum seed, Calophylluminophyllum shell, saw dust, banana strand, palm
tree trunk, coconut tree trunk, unused gunny bag.
8
In yet another embodiment, the additive used is selected from Pungampinnata oil, Moringaolefera
and sugarless gum from Azadirachtaindica, Manihotesculentaroot paste, wet rice powder, starch,
either individually or in any combination.
In yet another embodiment, the binder used is selected from cotton Gossypiumvitifolium seed waste
concentrate, sugarcane waste.
In yet another embodiment, exhibits emission on combustion essentially involving 40-60 % CO2,,
10-15%NO2, 10-20 % VOC, 8-14% S02, the said fuel further exhibiting a calorific value in the
range of 15000-30000 kJ/Kg, the bottom ash generated on combustion of the pellet at a temperature
in the range of 500-1500°C in air, being not more than 10 % by weight.
In yet another embodiment, a process for the preparation of the novel pellet fuel, comprises
a. treating collagenous substance with ultra-violate rays in the visible range from 300-
800 nm at a temperature in the range of 40-95°C to obtain heavy metal free substance,
b. adding to the heavy metal free substance, as obtained in step(i), not more than 95 %
by weight of organic matter exhibiting calorific value in the range of 14-18 KJ/Kg,
followed by adjusting the particle size of the resulting substrate in the range of 3mm
to 8mm,
c. adding to the substrate, as obtained in step(ii), 0.5 to 5 % w/w, of additive and 3 to 10
% w/w, of binder under shaking condition to obtain a homogenous slurry,
d. subjecting the slurry, as obtained in step(iii), to a pressure of 5 -9kN/cm2 at a
temperature of 140-200°C followed by drying at a temperature in the range of 100 to
200°C to obtain pellet fuel.
DETAILED DESCRIPTION OF THE INVENTION
The invention is described below in detail.
Collagenous substance obtained from In-house tannery of Tannary Division, Central Leather
Research Institute, Adyar, Chennai-600020 (Annexure -1), istreated with ultra-violate rays in the
y
visible range from 300-800 nm at a temperature in the range of 40-95°C to remove excess of
moisture to obtain heavy metal free substance. Not more than 95% by weight of organic matter
exhibiting calorific value in the range of 14-18KJ/Kg is added to it. The particle size of the resulting
material is adjusted in the range of 3mm to 9mm.It is blended with 0.5 to 5 % w/w, of additive and 3
to 10 % w/w, of binder under stirring condition to obtain homogenous slurry. It is subjected to a
pressure of 5 -9kN/cm2 at a temperature of 140-200°C followed by drying at a temperature in the
range of 100 to 200°C to obtain pellet fuel.
The pellet fuel exhibits the following characteristics:
Diameter of the circular cross section : 3-9 mm
Density 0.8 to 3 gm/cc
Moisture content 10-15%
Calorific value 15000-30000 kJ/Kg
Emission on combustion
40-60 % C02
10-15%NO2
10-20 %VOC
8-14% S02
Bottom ash generated on combustion of the pellet at a temperature in the range of 500-1500°C in air
not more than 10%.
The following examples are given by way of illustration only and therefore should not be construed
to limit the scope of the present invention.
EXAMPLE: 1
93gms of raw skin trimming from tannery was taken in a beaker and exposed to Ultraviolet ray at
45°C, 1 g of saw dust was added to it and mixed well. The resulting material was pulverized and the
particle size was found to be 3 mm. The material was mixed with 2gm of wet rice powder and 3gm
of 1 % aqueous sugarcane waste was added mixed under continuous stirring, shredding, pulverizing,
heating to drying at 110°C, pelletizing by means of hydraulic press at a heat of 200°C under a force
10
of 9kN/cm2. The resulting pellet fuel was kept in desiccator to maintain the moisture content less
than 10% and packed in a sealed bag and stored to avoid further absorption of moisture.
The pellet fuel was subjected to characterization and the following results were obtained.
Diameter of the circular cross section: 3mm
Density : 0.8 gm/cc
Moisture content : 10%
Calorific value of pellet : 15000kJ/Kg
Emission on combustion
40% C02l,
10%NO2,
10% VOC,
8% S02
Bottom ash generated on combustion of: 5%
pellet at a temperature in the range of
500-1500°Cinair
EXAMPLE: 2
94gms of raw skin trimming from tannery was taken in a beaker and exposed to Ultraviolet ray at
45°C, 2 g of timber/ timber dust was added to it and mixed well. The resulting material was
pulverized and the particle size was found to be 5 mm. The material was mixed with lgm of
Moringaolefera and sugarless gum from Azadirachtaindica and 4gm of 1% aqueous plant essence
like cotton Gossypiumvitifolium seed waste concentrate was added mixed under continuous stirring,,
shredding, pulverizing, heating to drying at 140°C, pelletizing by means of hydraulic press at a heat
of 180°C under a force of 8kN/cm2. The resulting pellet fuel was kept in desiccator to maintain the
moisture content less than 10% and packed in a sealed bag and stored to avoid further absorption of
moisture.
The pellet fuel was subjected to characterization and the following results were obtained.
l l
Diameter of the circular cross section: 5mm
Density of pellet : 1.5gm/cc
Moisture content : 9%
Calorific value : 18000kJ/Kg
Emission on combustion
50% C02,,
12%N02,
10%VOC,
10%SO2
Bottom ash generated on combustion of: 7%
pellet at a temperature in the range of
500-1500°Cinair
EXAMPLE: 3
92 gms of raw skin trimming from tannery was taken in a beaker and exposed to Ultraviolet ray at
45°C, 4 g of Calophylluminophyllum seed and its shell was added to it and mixed well. The resulting
material was pulverized and the particle size was found to be 7 mm. The material was mixed with
lgm of Manihotesculenta root paste and 3gm of 1% aqueous sugarcane wastes was mixed
thoroughly under continuous stirring, shredding, pulverizing, heating to drying at 110°C, pelletizing
by means of hydraulic press at a heat of 150°C under a force of 6kN/cm2. The resulting pellet fuel
was kept in desiccator to maintain the moisture content less than 10% and packed in a sealed bag and
stored to avoid further absorption of moisture.
The pellet fuel was subjected to characterization and the following results were obtained.
Diameter of the circular cross section: 7mm
Density of pellet : 1.4gm/cc
Moisture content : 6%
Calorific value: 23000kJ/Kg
Emission on combustion
12
40% C02,
10%NO2,
20% VOC,
12% S02
Bottom ash generated on combustion of: 3%
pellet at a temperature in the range of
500-1500°Cinair
EXAMPLE: 4
91gms of raw skin trimming from tannery was taken in a beaker and exposed to Ultraviolet ray at
45°C, 2g of palm tree trunk/coconus tree trunk was added to it and mixed well. The resulting
material was pulverized and the particle size was found to be 9 mm. The material was mixed with
3gm Pungampinnata oil, lg starch and 5gm of cotton Gossypiumvitifolium seed waste concentrate
was mixed thoroughly under continuous stirring, shredding, pulverizing, heating to drying at 120°C,
pelletizing by means of hydraulic press at a heat of 140°C under a force of 5 kN/cm2.The resulting
pellet fuel was kept in desiccator to maintain the moisture content less than 10% and packed in a
sealed bag and stored to avoid further absorption of moisture. The pellet fuel was subjected to
characterization and the following results were obtained.
Diameter of the circular cross section: 9mm
Density of pellet : 1.4gm/cc
Moisture content : 6%
Calorific value: 23000kJ/Kg
13
Emission on combustion
40% C02,
10%NO2,
20% VOC,
12% S02
Bottom ash generated on combustion of: 3%
pellet at a temperature in the range of
500-1500°Cinair
Advantages of the present invention
1. A hazardous tannery polluted solid waste treatment process in which combustible fuel pellet is
processed to provide high calorific value.
2. Alternative fuel, high calorific value, high power density, high energy density, low ash content, low
emission, good value added product.
3. Reduction of C02 to 50% from hazardous tannery and other organic wastes.
4. Composition of biodegradable additives and binder from natural source hence, less toxic.
5. Consumption of fossil fuel is reduced or eliminated, Land fill is avoided, low level of dust, easy
processing, long life, easy transportation, low handling loss.
6. Tannery Pollution is reduced/eliminated, hence environment and ground water is protected - an
eco-friendly process.
7. The pellet fuel of the invention is prepared by an eco-friendly method using biodegradable binder
and plasticizer with at least one organic matter selected from tannery collagenous wastes.
8. The invention paves way by utilization of tannery wastes and to convert them into a cost effective,
alternative pellet fuel to eliminate/reduce the consumption of fossil fuel.
14

We Claim
1. A novel pellet fuel comprising collagenous substances, organic matter, binder and additive,
the said pellet fuel has density in the range of 0.8 to 3 gm/cc and moisture content in the
range of 10 to 15% by weight.
2. A novel pellet fuel as claimed in claim 1, wherein the cross-section of the pellet being
substantially circular exhibiting a diameter in the range of 5 to 15 mm.
3. A novel pellet fuel as claimed in claim 1, wherein the collagenous substances used is selected
from shaving wastes of hides/skins, trimming wastes of hides/skins, fleshing wastes of
hide/skin.
4. A novel pellet fuel as claimed in claim 1, wherein the organic matter used is such as weeds,
timber, timber dust, coir pith dust,Calophylluminophyllum seed, Calophylluminophyllum
shell, saw dust, banana strand, palm tree trunk, coconut tree trunk, unused gunny bag.
5. A novel pellet fuel as claimed in claim 1, wherein the additive used is selected from
Pungampinnata oil, Moringaolefera and sugarless gum from Azadirachtaindica,
Manihotesculentaroot paste, wet rice powder, starch, either individually or in any
combination.
6. A novel pellet fuel as claimed in claim 1, wherein the binder used is selected from cotton
Gossypiumvitifolium seed waste concentrate, sugarcane waste.
7. A novel pellet fuel as claimed in claim 1, exhibits emission on combustion essentially
involving 40 to 60 % C02,, 10 to 15%N02, 10 to 20 % VOC, 8 to 14% S02, the said fuel
further exhibiting a calorific value in the range of 15000 to 30000 kJ/Kg, the bottom ash
generated on combustion of the pellet at a temperature in the range of 500 to 1500°C in air,
being not more than 10 % by weight.
8. A process for the preparation of the novel pellet fuel, comprises
15
o a t f ^
!2 0 Mil
a. treating collagenous substance with ultra-violate rays in the visible range from 300 to
800 nm at a temperature in the range of 40-95°C to obtain heavy metal free substance,
b. adding to the heavy metal free substance, as obtained in step(i), not more than 95 %
by weight of organic matter exhibiting calorific value in the range of 14 to 18 KJ/Kg,
followed by adjusting the particle size of the resulting substrate in the range of 3mm
to 8mm,
c. adding to the substrate, as obtained in step(ii), 0.5 to 5 % w/w, of additive and 3 to 10
% w/w, of binder under shaking condition to obtain a homogenous slurry,
d. subjecting the slurry, as obtained in step(iii), to a pressure of 5 to 9kN/cm at a
temperature of 140 to 200°C followed by drying at a temperature in the range of 100
to 200°C to obtain pellet fuel.
day of .^t^rtl 2014
Scientist
Innovation Protection Unit
Council of Scientific and Industrial Research
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LP.LJ. (C.S.i.R.) •
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16