Title of Invention	BIOMASS FUEL SUPPLY SYSTEM
Abstract	To achieve effective and efficient combustion while satisfying the load demand, controlled fuel supply is of paramount importance. The present invention relates to an energy efficient system for supplying metered fuel, in particular biomass fuel such as bagasse, wood chips, bark etc. to furnace. The system of the present invention obviates the problems such as fuel jamming, bridging of fuel due to uneven distribution, formation of fuel lumps etc, encounted in the conventional systems. Moreover, the present invention results in substantial reduction in power consumption of the system by virtue of judicious combination of rotatable cylinder provided with profiled structures.

Title of Invention

BIOMASS FUEL SUPPLY SYSTEM

Abstract

To achieve effective and efficient combustion while satisfying the load demand, controlled fuel supply is of paramount importance. The present invention relates to an energy efficient system for supplying metered fuel, in particular biomass fuel such as bagasse, wood chips, bark etc. to furnace. The system of the present invention obviates the problems such as fuel jamming, bridging of fuel due to uneven distribution, formation of fuel lumps etc, encounted in the conventional systems. Moreover, the present invention results in substantial reduction in power consumption of the system by virtue of judicious combination of rotatable cylinder provided with profiled structures.

Full Text	FORM - 2 THE PATENTS ACT, 1970 (39 OF 1970) COMPLETE SPECIFICATION (See Section 10) TITLE OF INVENTION "Biomass Fuel Supply System" (a) Thermax Limited (b) having administrative office at D-1, MIDC, Chinchwad, Pune411 019 India The following specification particularly describes the nature of the invention and the manner in which it is to be performed. Field of Invention The present invention relates to an energy efficient system for supplying metered fuel, in particular biomass fuel such as bagasse, wood chips, bark etc. to furnace. Background of the Invention In the process of combustion, fuel is an integral part because combustion is the process of fuel oxidation. To achieve effective and efficient combustion while satisfying the load demand, controlled fuel supply is of paramount importance. The construction of the fuel supply system depends on the nature of the fuel, particularly solid fuels. Generally, the solid fuel is stored in a container and is supplied to the furnace through/ via chutes, screw feeders and stoker. In case of sugar factory, biomass fuel known as bagasse (residue of sugarcane after juice extraction) is used as a fuel and is continuously supplied to the boiler furnace after juice extraction from; mills. It is very important to have precise control on the fuel mass flow rate to the furnace to meet transient steam demand in boilers. Application of the biomass fuel supply system used for co-generation plant such as sugar. factory, demands biomass fuel storage capacity for about 10 to 20 minutes. This requires tall storage silo which cause excessive torque and jamming of the screw feeder. The problem of fuel jamming further aggravates in case of the fibrous fuel like bagasse. The fuel jamming results in interrupted fuel supply to furnace. Thus, it is required to provide a system, to supply biomass fuel to screw feeders so as to avoid jamming. These systems are reported in the prior art. They are as follows: U.S Patent 6,409,110 discloses an apparatus for processing compacted biomass, such as bales of hay, straw or other similar material, into a form which is suitable to be used to fire a furnace. The compacted biomass is forwarded in the processing apparatus in a controlled manner by a mainly horizontal conveying system. There are two rollers, rotated in opposite direction with different peripheral speeds. Further the rollers are provided with teeth-like elements projecting from the outer surfaces to engage the compacted biomass material on formed between the two rollers. However, this system suffers from a drawback that it uses horizontal conveying system for fuel feeding that requires additional drive. Further, since the peripheral speeds of the two rollers are different, separate drives are necessary which increases power consumption of the system. Single roller biomass feeding systems are also reported in the literature. They suffer from the following drawbacks: > tendency of fuel jamming / chocking due to the contact and rubbing of the fuel with the stationary parts of the system resulting in erratic control of the fuel; > bridging of the fuel due to the uneven distribution of the weight of the fuel column on the roller drum; > increased power consumption due to the resistance of the fuel column to the rotation of the roller and heavy weight of the roller itself; > formation of lumps of fuel; > increased response time; > active control on the fuel supply can not be achieved. Fuel supply systems using more than two rollers are also reported in the literature. They suffer from the limitation that increased number of rollers increases weight and power consumption of the system. Necessity has constantly been felt to develop a simple, light weight, easy to fabricate : biomass fuel supply system with substantially reduced power consumption obviating fuel jamming, bridging, and lump formation. The present invention addresses drawbacks of the prior art. Summary of the Invention The main object of the invention is to provide energy efficient system for supplying metered biomass fuel to furnace obviating fuel jamming, Another object of the invention is to reduce weight of the system. Yet another object of the invention is to eliminate fuel bridging thereby ensuring uninterrupted fuel supply. Another object of the invention is to provide a system which facilitates precise control of fuel mass flow rate. Yet another object of the invention is to improve response time of the system. Another object of the invention is to avoid rubbing of the fuel with stationary parts of the system thereby avoiding fuel sticking and accumulation of the same in the system. Another object of the invention is to provide a system that can handle multiple biomass fuels with precise control on fuel supply rate as per boiler load. . Thus in accordance with the invention, the biomass fuel-supply system comprises of: a provision for biomass storage; a housing mounted with first rotatable cylinder that is provided with one or plurality of profiled structure/s projecting from its outer round surface / periphery; second rotatable cylinder provided with one or plurality of profiled structure/s mounted on its outer round surface / periphery; driving and transmission means for rotation of the said cylinders in opposite direction; longitudinally extending guide/s positioned at the top of the said cylinder/s to guide biomass fuel over the said cylinders; one or plurality of members positioned at the bottom of the said cylinders projecting from the said housing towards the said two cylinders and disposed in between the said profiled structures of the two cylinders, for removing attached biomass fuel from the surfaces of the cylinders and profiled structures. Description of the Invention Features and advantages of this invention will become apparent in the following detailed description and the preferred embodiments with reference to the accompanying drawings. Figure 1: Schematic of the fuel supply system (Sheet 1) The fuel supply system comprises of fuel storage provision 1 mounted on the housing 2. The first rotatable cylinder 3 and second rotatable cylinder 4 extends longitudinally and is mounted in the said housing. The length of the said cylinder is selected depending on the fuel used and fuel supply capacity of the system. The cylinders 3 and 4 are provided with one or plurality of profiled structures 5 and 6 respectively projecting out from the cylinder surface. The said profiled structures are provided on the outer surface of the said cylinders at a particular pitch depending on the capacity of the system and type of fuel used. One or Plurality of members 7 and 8 are mounted on the said housing near the bottom of 3, 4, and extend along the length of the housing. The said members are positioned in between profiled structures and project towards the cylinders and almost touch the surface of the said cylinder. The guides 9 and 10 are positioned above 3 and 4 respectively and extend along the length of the cylinders. The cylinders are rotated using a variable speed driving means and transmission means. The guides are positioned in such a way that the weight of the biomass fuel assists rotation of the cylinders and obviates bridge formation. In one of the embodiments the center of the said two cylinders is at the same height. In another embodiment the said guides are positioned at the same height or different heights. In one of the embodiments two rotatable cylinders are of equal diameters. In another embodiment the two rotatable cylinders are of different diameters. In yet another embodiment the said profiled structures of the cylinder are of equal dimensions, size and shape. In yet another embodiment the cylinder surface is treated with anticorrosive, wear resistant material. Example: The following example illustrates that the energy consumption present invention is substantially reduced as against systems using single cylinder. The experiments are conducted using bagasse (fibrous residue of sugarcane) as a biomass fuel. The trials were carried out with the same height of bagasse in the storage provision for single cylinder system and fuel supply system of the present invention. The rotational speeds of the systems were adjusted so that the fuel supply rate for both the system is equal. Thus, keeping other variables equal and constant energy consumption of the two systems was measured. It was observed that the system of the present invention consumed 7.5 kW as against 10 kW for single cylinder system. Thus there is 25% reduction in energy consumption. We Claim: 1. A biomass fuel supply system comprising a provision for biomass storage; . a housing mounted with first rotatable cylinder that is provided with one or plurality of profiled structure/s projecting from its outer round surface, second rotatable cylinder provided with one or plurality of profiled structure/s mounted on its outer round surface; driving and transmission means for rotation of the said cylinders in opposite direction; longitudinally extending guide/s positioned at the top of the said cylinder/s to guide biomass fuel over the said cylinders; one or plurality of members positioned at the bottom of the said cylinders projecting from the said housing towards the said two cylinders and disposed in between the said profiled structures of the two cylinders, for removing attached biomass fuel from the surfaces of the cylinders and profiled structures. 2. A biomass fuel supply system as claimed in claim 1 wherein diameters of the said rotatable cylinders are equal. 3. A biomass fuel supply system as claimed in claims 1-2 wherein the diameters of the said rotatable cylinders are unequal. 4. A biomass fuel supply system as claimed in claims 1 wherein the centers of rotation of the said two cylinders are at equal height or different heights. 5. A biomass fuel supply system as claimed in claims 1, 4 wherein the centers of rotation of the said two cylinders are at different heights. 6. A biomass fuel supply system as claimed in claims 1-5 wherein the profiled structures are attached to the outer surface of the said cylinders. 7. A biomass fuel supply system as claimed in claims 1-6 wherein profiled structures of the first and second cylinder are of the same dimensions and shape. 8. A biomass fuel supply system as claimed in claims 1-7 wherein the profiled structures of the first and second cylinder are of different dimension and shape. 9. A biomass fuel supply system as claimed in claims 1-8 wherein the said cylinders are rotated at different speeds using variable speed driving and transmission means. 10. A biomass fuel supply system as claimed in claim 1 wherein the biomass fuel is of fibrous nature such as bagasse, wood chips, bark etc. Date: 4/09/2006 Applicant 'Thermax Limited Abstract To achieve effective and efficient combustion while satisfying the load demand, controlled fuel supply is of paramount importance. The present invention relates to an energy efficient system for supplying metered fuel, in particular biomass fuel such as bagasse, wood chips, bark etc. to furnace. The system of the present invention obviates the problems such as fuel jamming, bridging of fuel due to uneven distribution, formation of fuel lumps etc, encountered in the conventional systems. Moreover, the present invention results in substantial reduction in power consumption of the system by virtue of judicious combination of rotatable cylinders provided with profiled structures.

Full Text

FORM - 2
THE PATENTS ACT, 1970
(39 OF 1970)
COMPLETE SPECIFICATION
(See Section 10)
TITLE OF INVENTION
"Biomass Fuel Supply System"
(a) Thermax Limited (b) having administrative office at D-1, MIDC, Chinchwad, Pune411 019 India
The following specification particularly describes the nature of the invention and the manner in which it is to be performed.

Field of Invention
The present invention relates to an energy efficient system for supplying metered fuel, in particular biomass fuel such as bagasse, wood chips, bark etc. to furnace.
Background of the Invention
In the process of combustion, fuel is an integral part because combustion is the process of fuel oxidation. To achieve effective and efficient combustion while satisfying the load demand, controlled fuel supply is of paramount importance. The construction of the fuel supply system depends on the nature of the fuel, particularly solid fuels. Generally, the solid fuel is stored in a container and is supplied to the furnace through/ via chutes, screw feeders and stoker. In case of sugar factory, biomass fuel known as bagasse (residue of sugarcane after juice extraction) is used as a fuel and is continuously supplied to the boiler furnace after juice extraction from; mills. It is very important to have precise control on the fuel mass flow rate to the furnace to meet transient steam demand in boilers.
Application of the biomass fuel supply system used for co-generation plant such as sugar. factory, demands biomass fuel storage capacity for about 10 to 20 minutes. This requires tall storage silo which cause excessive torque and jamming of the screw feeder. The problem of fuel jamming further aggravates in case of the fibrous fuel like bagasse. The fuel jamming results in interrupted fuel supply to furnace. Thus, it is required to provide a system, to supply biomass fuel to screw feeders so as to avoid jamming. These systems are reported in the prior art. They are as follows:
U.S Patent 6,409,110 discloses an apparatus for processing compacted biomass, such as bales of hay, straw or other similar material, into a form which is suitable to be used to fire a furnace. The compacted biomass is forwarded in the processing apparatus in a controlled manner by a mainly horizontal conveying system. There are two rollers, rotated in opposite direction with different peripheral speeds. Further the rollers are provided with teeth-like elements projecting from the outer surfaces to engage the compacted biomass material on

formed between the two rollers. However, this system suffers from a drawback that it uses horizontal conveying system for fuel feeding that requires additional drive. Further, since the peripheral speeds of the two rollers are different, separate drives are necessary which increases power consumption of the system.
Single roller biomass feeding systems are also reported in the literature. They suffer from the following drawbacks:
> tendency of fuel jamming / chocking due to the contact and rubbing of the fuel with the stationary parts of the system resulting in erratic control of the fuel;
> bridging of the fuel due to the uneven distribution of the weight of the fuel column on the roller drum;
> increased power consumption due to the resistance of the fuel column to the rotation of the roller and heavy weight of the roller itself;
> formation of lumps of fuel;
> increased response time;
> active control on the fuel supply can not be achieved.
Fuel supply systems using more than two rollers are also reported in the literature. They suffer from the limitation that increased number of rollers increases weight and power consumption of the system.
Necessity has constantly been felt to develop a simple, light weight, easy to fabricate : biomass fuel supply system with substantially reduced power consumption obviating fuel jamming, bridging, and lump formation.
The present invention addresses drawbacks of the prior art. Summary of the Invention
The main object of the invention is to provide energy efficient system for supplying metered biomass fuel to furnace obviating fuel jamming,
Another object of the invention is to reduce weight of the system.

Yet another object of the invention is to eliminate fuel bridging thereby ensuring uninterrupted fuel supply.
Another object of the invention is to provide a system which facilitates precise control of fuel mass flow rate.
Yet another object of the invention is to improve response time of the system.
Another object of the invention is to avoid rubbing of the fuel with stationary parts of the system thereby avoiding fuel sticking and accumulation of the same in the system.
Another object of the invention is to provide a system that can handle multiple biomass fuels with precise control on fuel supply rate as per boiler load.
. Thus in accordance with the invention, the biomass fuel-supply system comprises of: a provision for biomass storage;
a housing mounted with first rotatable cylinder that is provided with one or plurality of profiled structure/s projecting from its outer round surface / periphery; second rotatable cylinder provided with one or plurality of profiled structure/s mounted on its outer round surface / periphery;
driving and transmission means for rotation of the said cylinders in opposite direction;
longitudinally extending guide/s positioned at the top of the said cylinder/s to guide biomass fuel over the said cylinders;
one or plurality of members positioned at the bottom of the said cylinders projecting from the said housing towards the said two cylinders and disposed in between the said profiled structures of the two cylinders, for removing attached biomass fuel from the surfaces of the cylinders and profiled structures.

Description of the Invention
Features and advantages of this invention will become apparent in the following detailed description and the preferred embodiments with reference to the accompanying drawings.
Figure 1: Schematic of the fuel supply system (Sheet 1)
The fuel supply system comprises of fuel storage provision 1 mounted on the housing 2. The first rotatable cylinder 3 and second rotatable cylinder 4 extends longitudinally and is mounted in the said housing. The length of the said cylinder is selected depending on the fuel used and fuel supply capacity of the system. The cylinders 3 and 4 are provided with one or plurality of profiled structures 5 and 6 respectively projecting out from the cylinder surface. The said profiled structures are provided on the outer surface of the said cylinders at a particular pitch depending on the capacity of the system and type of fuel used. One or Plurality of members 7 and 8 are mounted on the said housing near the bottom of 3, 4, and extend along the length of the housing. The said members are positioned in between profiled structures and project towards the cylinders and almost touch the surface of the said cylinder. The guides 9 and 10 are positioned above 3 and 4 respectively and extend along the length of the cylinders. The cylinders are rotated using a variable speed driving means and transmission means. The guides are positioned in such a way that the weight of the biomass fuel assists rotation of the cylinders and obviates bridge formation.
In one of the embodiments the center of the said two cylinders is at the same height.
In another embodiment the said guides are positioned at the same height or different heights.
In one of the embodiments two rotatable cylinders are of equal diameters.
In another embodiment the two rotatable cylinders are of different diameters.

In yet another embodiment the said profiled structures of the cylinder are of equal dimensions, size and shape.
In yet another embodiment the cylinder surface is treated with anticorrosive, wear resistant material.
Example:
The following example illustrates that the energy consumption present invention is substantially reduced as against systems using single cylinder.
The experiments are conducted using bagasse (fibrous residue of sugarcane) as a biomass fuel. The trials were carried out with the same height of bagasse in the storage provision for single cylinder system and fuel supply system of the present invention. The rotational speeds of the systems were adjusted so that the fuel supply rate for both the system is equal. Thus, keeping other variables equal and constant energy consumption of the two systems was measured.
It was observed that the system of the present invention consumed 7.5 kW as against 10 kW for single cylinder system. Thus there is 25% reduction in energy consumption.

We Claim:
1. A biomass fuel supply system comprising
a provision for biomass storage;
. a housing mounted with first rotatable cylinder that is provided with one or plurality of profiled structure/s projecting from its outer round surface, second rotatable cylinder provided with one or plurality of profiled structure/s mounted on its outer round surface;
driving and transmission means for rotation of the said cylinders in opposite direction;
longitudinally extending guide/s positioned at the top of the said cylinder/s to guide biomass fuel over the said cylinders;
one or plurality of members positioned at the bottom of the said cylinders projecting from the said housing towards the said two cylinders and disposed in between the said profiled structures of the two cylinders, for removing attached biomass fuel from the surfaces of the cylinders and profiled structures.
2. A biomass fuel supply system as claimed in claim 1 wherein diameters of the said rotatable cylinders are equal.
3. A biomass fuel supply system as claimed in claims 1-2 wherein the diameters of the said rotatable cylinders are unequal.
4. A biomass fuel supply system as claimed in claims 1 wherein the centers of rotation of the said two cylinders are at equal height or different heights.
5. A biomass fuel supply system as claimed in claims 1, 4 wherein the centers of rotation of the said two cylinders are at different heights.
6. A biomass fuel supply system as claimed in claims 1-5 wherein the profiled structures are attached to the outer surface of the said cylinders.

7. A biomass fuel supply system as claimed in claims 1-6 wherein profiled
structures of the first and second cylinder are of the same dimensions and
shape.
8. A biomass fuel supply system as claimed in claims 1-7 wherein the profiled
structures of the first and second cylinder are of different dimension and shape.
9. A biomass fuel supply system as claimed in claims 1-8 wherein the said cylinders are rotated at different speeds using variable speed driving and transmission means.
10. A biomass fuel supply system as claimed in claim 1 wherein the biomass fuel is of fibrous nature such as bagasse, wood chips, bark etc.
Date: 4/09/2006
Applicant 'Thermax Limited

Abstract

To achieve effective and efficient combustion while satisfying the load demand, controlled fuel supply is of paramount importance. The present invention relates to an energy efficient system for supplying metered fuel, in particular biomass fuel such as bagasse, wood chips, bark etc. to furnace. The system of the present invention obviates the problems such as fuel jamming, bridging of fuel due to uneven distribution, formation of fuel lumps etc, encountered in the conventional systems. Moreover, the present invention results in substantial reduction in power consumption of the system by virtue of judicious combination of rotatable cylinders provided with profiled structures.

BIOMASS FUEL SUPPLY SYSTEM

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