Title of Invention	"MULTI FUEL FIRING BED"
Abstract	This invention relates to a multi fuel firing bed assembly comprising a drive system having means for growth of shaft in the drive couplings to take care of higher operation temperatures of moving bed and a second means for accommodating thermal expansion, the alignment of which is not disturbed even at elevated temperatures, and the usage of under bed air with higher temperature, integrated oil cooler, and locking system, said drive system being self lubricated and provided with lubricating ports and strategic arrangement so as to maintain smoother operation with reduced wear and tear.

Title of Invention

"MULTI FUEL FIRING BED"

Abstract

This invention relates to a multi fuel firing bed assembly comprising a drive system having means for growth of shaft in the drive couplings to take care of higher operation temperatures of moving bed and a second means for accommodating thermal expansion, the alignment of which is not disturbed even at elevated temperatures, and the usage of under bed air with higher temperature, integrated oil cooler, and locking system, said drive system being self lubricated and provided with lubricating ports and strategic arrangement so as to maintain smoother operation with reduced wear and tear.

Full Text	FIELD OF INVENTION The present invention relates to multi fuel firing bed. The invention particularly relates to an improved fuel firing bed of the steam generator. More particularly, the bed is designed for firing variety of fuels viz. bagasse, coal, lignite, wood chips and biomass fuels independently or in any combination more effectively and efficiently, BACKGROUND OF THE INVENTION Among non conventional energy sources, biomass plays a vital role. A cost-effective and environmentally compatible energy use of biomass fuels requires more efficient, maintenance free conversion technologies involving innovative design techniques compared to the conventional combustors. Most types of biomass are difficult fuels in terms of low heating value, low bulk density, high moisture, higher chlorides and alkalis. Bagasse and the peripheral sugar cane wastes are no different from the standard biofuels. Bagasse has low sulfur, high moisture and high level of alkalis. Current firing systems operate at lower boiler plant efficiency and frequently taken out of service for maintenance. The higher levels of unburnt carbon in the ash from these fuels makes the ash less suitable for profitable uses. As sugar can cultivation is seasonal, availability of bagasse is not ensured throughout the year and hence the power generation. To overcome this, the generating units are operated using bagasse whenever available and for the rest of the periods the unit can be operated with other fossil fuels like coal or with other bio-mass fuels like bark, peanut husk, coconut shell, wood chips etc. Hence the firing system should take care of burning variety of fuels in more effective way. The situation becomes more complex, when combination of firing with bagasse and coal or wood chips or biomass is envisaged. There are frequent failure of drives, damages of bearings, leakages of furnace buff, higher levels of unburnt carbon, low preheated and improperly distributed under bed air and over fire air. This results in frequent interruption to power generation and supply to grid, steam supply for processing, unsafe conditions near furnace areas, inefficient combustion and fuel carry over and fire hazard at economizer hoppers and at electrostatic precipitators. All these technical, performance and safety requirements are addressed in this invention by 1) Introduction of self lubricated drives. 2) Innovative provision for shaft growth within the drive couplings. 3) Integrated oil cooler for drives. 4) Innovative locking arrangement for bearings. 5) Innovative and effective sealing systems. 6) Strategically placed air entries for underbed air. 7) Three level over fire air system. 8) Superior scale resistant materials for bed and allied areas for extended life. 9) Usage of highly preheated air. 10) Relative case hardened parts to ensure minimum wear, better durability, less maintenance time and cost. 11) Innovative jack system for easy maiantenance. US Patent No. 4,026,410 dated May 31, 1977 under the Traveling grate chain by Korting; Reinhard discloses an apparatus having a plurality parallel strands comprising chain links which are articulately connected together by grate pins that extend transversely over the entire width of grate. Construction of the apparatus of this US Patent is different from the present invention. us Patent No,4,398,473 dated August 16, 1983 under the Stocker backstop by Loper; Dossie H. describes an art in which a wood burning stoker grate is provided a barrier across its rear end functioning as an impact surface for fuel and foreign matter projected toward the rear of the stoker grate. This arrangement in the present invention is an integrated part of sealing system, which takes care of furnace expansion and rear air sealing. US Patent No.5,839,376 dated November 24, 1998 under the Stoker with universal key construction by Barlow; Dennis N. describes an art in which the arrangement and construction is different from this invention. OBJECTS AND SUMMARY OF THE PRESENT INVENTION 1) An object of this invention is to provide an innovative self lubricated, reliable drive system for the movement of bed so that the failure of the drive due to wear and tear is avoided. 2) Another object of this Invention is to provide thermal * expansion provision in the drive couplings to take care of growth of shaft due to higher operating temperature of moving bed. Because of innovative provisions for thermal expansion, the alignment is not disturbed throughout the operation even at elevated temperatures. 3) A still another object of this invention is to provide integrated oil cooler for the hydraulic drive, to maintain the oil temperature so as to prevent the thermal cracking of oil due to higher temperatures. Frequent changeover of oil is avoided. Higher performance and extended life of intricate design directional values and flow control values are ensured. 4) A further object of the present invention is to provide innovative locking arrangement for bearings, which ensures extended life for bearings. 5) A still further object of innovation is to provide innovative sealing arrangement, which ensures effective distribution of combustion air to intended purposes by isrresting the leakages to other areas. Effective sliding seal arrangement arrests the leakage of furnace buffs, if released . 6) A still another object of innovation is to provide strategic underbed air entries on both sides of the bed firing system. 7) Yet another object of the present invention is that the over fired air is introduced at three levels to combustion chamber (furnace) which curtails the unburnt carbon level and arrests the fuel carry over. 8> Another object of the innovation is that the superior scale resistant materials are selected for bed and allied areas for extended life. 9) It is another object of this innovation is to use highly preheated underbed air to obtain higher efficency. 10) It is still another object of the present inovation is that the strategic jack arrangement, which ensures easy maintenance in a very short time. 11) It is still another object of the innovation is that relatively care hardened parts are used to ensure minimum wear, better durability , less maintenance time and cost. Thus the present invention provides a multi fuel firing bed assembly capable of burning a variety of fuels from coal to biomass comprising a drive system, said drive system being self lubricated and provided with lubricating ports at strategic locations so as to maintain smoother operation with reduced wear and tear. In the above multi fuel bed assembly the drive system comprises means for growth of shaft in the drive couplings to take care of higher operating temperatures of moving bed, and a second means for accommodating thermal expansion, the alignment of which is not distributed even at elevated temperatures, and the usage of underbed air with higher temperature. In the aforesaid multi fuel firing bed wherein an integrated oil cooler for the drive is adapted to maintain the oil temperature so as to prevent the thermal cracking of oil due to higher temperatures. In the multi fuel firing bed as described herein a locking system for bearings is provided, said locking system is adapted to movement, avoiding the damage to bearings and ensuring long trouble free life. The said multi fuel firing bed is provided with an innovating sealing arrangement to ensure effective distribution of combustion air to intended purposes by arresting the leakages to other areas, leakage of furnace buffs arrests the ingress of air into the furnace thereby reducing excess air levels. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS in the drawings: Fig.l shows the arrangement of multi fuel firing bed in a steam generator. Fig.2 shows the detail view of the bearing area with locking arrangement and jack system. Fig.3 shows the arrangement of drive system with integrated cooler and self lubrication ports. Fig,4 shows the coupling connecting the bed with the drive. Fig.5 shows the slide sealing arrangement. DETAILED DESCRIPTION OF THE InVENTION Referring to the drawings, the arrangement has a firing bed (01), which runs continuously in the direction of arrow as shown. The fuel distributors direct the fuels on to the upper surface of the moving bed. The underbed air is supplied on both sides through strategically located air entries in the air hopper. The bed is driven by a drive provided with self lubrication ports (03) for smoother operation and to reduce wear and tear and thus ensuring long trouble free performance. The drive is provided with oil cooler (04), which cools the oil to maintain the temperature within the working range, thus avoiding thermal cracking and damage to control and directional valves (05) The couplings (06) are provided with provision for thermal growth of shafts, thus allowing higher preheating of undertaed air which results efficient burning of variety fuels even with high moisture. Innovative locking arrangement (07) for the bearings are provided, which arrests lateral movement and thereby the damage to bearings are avoided. The life of the bearings extended by arresting the lateral and rotary movements by this arrangement. Innovative and effective sliding seal sealing arrangement (08) at front and sides are provided to arrest the leakage of furnace buffs, which ensures safe atmosphere for the operators. This also arrests the ingress of the air into the furnace, thereby reducing the excess air level and improving thermal efficiency of the steam generator. Over fire air is supplied at three levels, including air boxes with regulating dampers (09), which helps the formation of air blanket with turbulence. As a result, residence time of fibrous fuels within the combustion chamber is increased, thereby arresting the fuel carry over. Innovative jack system arrangement (10), helps easy lifting of entire bed to a substantial amount for replacement of bearing and for maintenance. WE CLAIM: 1. A multi fuel firing bed assembly comprising a drive system having means for growth of shaft in the drive couplings to take care of higher operation temperatures of moving bed and a second means for accommodating thermal expansion, the alignment of which is not disturbed even at elevated temperatures, and the usage of under bed air with higher temperature, integrated oil cooler, and locking system, said drive system being self lubricated and provided with lubricating ports and strategic arrangement so as to maintain smoother operation with reduced wear and tear. 2. A multi fuel firing bed assembly as claimed in claim 1, wherein an integrated oil cooler for the drive is adapted to maintain the oil temperature so as to prevent the thermal cracking of oil due to higher temperatures. 3. A multi fuel firing bed assembly as claimed in claim 1, wherein the said locking system is adapted to arrest the lateral and rotary movement, avoiding the damage to bearings and ensuring long trouble free life. 4. A multi fuel firing bed assembly as claimed in any of the preceding claims, hardened parts are used to ensure minimum wear, better durability, less maintenance time and cost. 5. A multi fuel firing bed assembly as claimed in claim 4, wherein scale resistant materials are selected for bed to extend life. 6. A multi fuel firing bed assembly as claimed in claim 5, wherein an innovative sealing arrangement is adapted to ensure effective distribution of combustion air to intended purposes by arresting the leakages to other areas, leakage of furnace buffs and arrests the ingress of air into the furnace thereby reducing excess air levels. 7. A multi fuel firing bed assembly as claimed in claim 6, wherein a highly preheated underbed air is used to obtain higher efficiency. 8. A multi fuel firing bed assembly as claimed in claim 1, wherein a strategic jack arrangement is adapted to ensure easy maintenance in a very short time. 9. A multi fuel firing bed assembly as claimed in claim 1, wherein a strategic underbed air entries is adapted on both sides of the firing system to ensure uniform distribution of air and to maintain uniform p across bed. 10. A multi fuel firing bed assembly as claimed in claim 1 and 9, wherein arrangement is made of over fire air at three levels including air boxes with regulating dampers to combustion chamber (furnace) which curtails the unburnt carbon level and arrests the fuel carry over.

Full Text

FIELD OF INVENTION
The present invention relates to multi fuel firing bed.
The invention particularly relates to an improved fuel firing bed of the steam generator. More particularly, the bed is designed for firing variety of fuels viz. bagasse, coal, lignite, wood chips and biomass fuels independently or in any combination more effectively and efficiently,
BACKGROUND OF THE INVENTION
Among non conventional energy sources, biomass plays a vital role. A cost-effective and environmentally compatible energy use of biomass fuels requires more efficient, maintenance free conversion technologies involving innovative design techniques compared to the conventional combustors. Most types of biomass are difficult fuels in terms of low heating value, low bulk density, high moisture, higher chlorides and alkalis. Bagasse and the peripheral sugar cane wastes are no different from the standard biofuels. Bagasse has low sulfur, high moisture and high level of alkalis. Current firing systems operate at lower boiler plant efficiency and frequently taken out of service for maintenance. The higher levels of unburnt carbon in the ash from these fuels makes the ash less suitable for profitable uses.
As sugar can cultivation is seasonal, availability of bagasse is not ensured throughout the year and hence the power generation. To overcome this, the generating units are operated using bagasse whenever available and for the rest of the periods the unit can be operated with other fossil fuels like coal or with other bio-mass fuels like bark, peanut husk, coconut shell, wood chips etc. Hence the firing system should take care of burning variety of fuels in more effective way. The situation becomes more complex, when combination of firing with bagasse and coal or wood chips or biomass is envisaged.
There are frequent failure of drives, damages of bearings, leakages of furnace buff, higher levels of unburnt carbon, low preheated and improperly distributed under bed air and over fire air. This results in frequent interruption to power generation and supply to grid, steam supply for processing, unsafe conditions near furnace areas, inefficient combustion and fuel carry over and fire hazard at economizer hoppers and at electrostatic precipitators.
All these technical, performance and safety requirements are addressed in this invention by
1) Introduction of self lubricated drives.
2) Innovative provision for shaft growth within the drive couplings.
3) Integrated oil cooler for drives.
4) Innovative locking arrangement for bearings.
5) Innovative and effective sealing systems.
6) Strategically placed air entries for underbed air.
7) Three level over fire air system.
8) Superior scale resistant materials for bed and allied areas for extended life.
9) Usage of highly preheated air.
10) Relative case hardened parts to ensure minimum wear, better durability, less maintenance time and cost.
11) Innovative jack system for easy maiantenance.
US Patent No. 4,026,410 dated May 31, 1977 under the Traveling grate chain by Korting; Reinhard discloses an apparatus having a plurality parallel strands comprising chain links which are articulately connected together by grate pins that extend transversely over the entire width of grate. Construction of the apparatus of this US Patent is different from the present invention.
us Patent No,4,398,473 dated August 16, 1983 under the Stocker backstop by Loper; Dossie H. describes an art in which a wood burning stoker grate is provided a barrier across its rear end functioning as an impact surface for fuel and foreign matter projected toward the rear of the stoker grate. This arrangement in the present invention is an integrated part of sealing system, which takes care of furnace expansion and rear air sealing.
US Patent No.5,839,376 dated November 24, 1998 under the Stoker with universal key construction by Barlow; Dennis N. describes an art in which the arrangement and construction is different from this invention.
OBJECTS AND SUMMARY OF THE PRESENT INVENTION
1) An object of this invention is to provide an innovative self
lubricated, reliable drive system for the movement of bed so
that the failure of the drive due to wear and tear is
avoided.
2) Another object of this Invention is to provide thermal *
expansion provision in the drive couplings to take care of
growth of shaft due to higher operating temperature of
moving bed. Because of innovative provisions for thermal
expansion, the alignment is not disturbed throughout the
operation even at elevated temperatures.
3) A still another object of this invention is to provide
integrated oil cooler for the hydraulic drive, to maintain
the oil temperature so as to prevent the thermal cracking
of oil due to higher temperatures. Frequent changeover of
oil is avoided. Higher performance and extended life of
intricate design directional values and flow control values are ensured.
4) A further object of the present invention is to provide innovative locking arrangement for bearings, which ensures extended life for bearings.
5) A still further object of innovation is to provide innovative sealing arrangement, which ensures effective distribution of combustion air to intended purposes by isrresting the leakages to other areas. Effective sliding seal arrangement arrests the leakage of furnace buffs, if released .
6) A still another object of innovation is to provide strategic underbed air entries on both sides of the bed firing system.
7) Yet another object of the present invention is that the over fired air is introduced at three levels to combustion chamber (furnace) which curtails the unburnt carbon level and arrests the fuel carry over.
8> Another object of the innovation is that the superior scale resistant materials are selected for bed and allied areas for extended life.
9) It is another object of this innovation is to use highly
preheated underbed air to obtain higher efficency.
10) It is still another object of the present inovation is
that the strategic jack arrangement, which ensures easy
maintenance in a very short time.
11) It is still another object of the innovation is that
relatively care hardened parts are used to ensure minimum
wear, better durability , less maintenance time and cost.
Thus the present invention provides a multi fuel firing bed assembly capable of burning a variety of fuels from coal to biomass comprising a drive system, said drive system being self lubricated and provided with lubricating ports at strategic locations so as to maintain smoother operation with reduced wear and tear.
In the above multi fuel bed assembly the drive system comprises means for growth of shaft in the drive couplings to take care of higher operating temperatures of moving bed, and a second means
for accommodating thermal expansion, the alignment of which is not distributed even at elevated temperatures, and the usage of underbed air with higher temperature.
In the aforesaid multi fuel firing bed wherein an integrated oil cooler for the drive is adapted to maintain the oil temperature so as to prevent the thermal cracking of oil due to higher temperatures.
In the multi fuel firing bed as described herein a locking system for bearings is provided, said locking system is adapted to movement, avoiding the damage to bearings and ensuring long trouble free life.
The said multi fuel firing bed is provided with an innovating sealing arrangement to ensure effective distribution of combustion air to intended purposes by arresting the leakages to other areas, leakage of furnace buffs arrests the ingress of air into the furnace thereby reducing excess air levels.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
in the drawings:
Fig.l shows the arrangement of multi fuel firing bed in a steam generator.
Fig.2 shows the detail view of the bearing area with locking arrangement and jack system.
Fig.3 shows the arrangement of drive system with integrated cooler and self lubrication ports.
Fig,4 shows the coupling connecting the bed with the drive.
Fig.5 shows the slide sealing arrangement.
DETAILED DESCRIPTION OF THE InVENTION
Referring to the drawings, the arrangement has a firing bed (01), which runs continuously in the direction of arrow as shown. The fuel distributors direct the fuels on to the upper surface of the moving bed. The underbed air is supplied on both sides through strategically located air entries in the air hopper. The bed is driven by a drive provided with self lubrication ports (03) for smoother operation and to reduce wear and tear and thus ensuring long trouble free performance. The drive is provided with oil cooler (04), which cools the oil to maintain the temperature within the working range, thus avoiding thermal cracking and damage to control and directional valves (05) The couplings (06) are provided with provision for thermal growth of
shafts, thus allowing higher preheating of undertaed air which results efficient burning of variety fuels even with high moisture. Innovative locking arrangement (07) for the bearings are provided, which arrests lateral movement and thereby the damage to bearings are avoided. The life of the bearings extended by arresting the lateral and rotary movements by this arrangement. Innovative and effective sliding seal sealing arrangement (08) at front and sides are provided to arrest the leakage of furnace buffs, which ensures safe atmosphere for the operators. This also arrests the ingress of the air into the furnace, thereby reducing the excess air level and improving thermal efficiency of the steam generator. Over fire air is supplied at three levels, including air boxes with regulating dampers (09), which helps the formation of air blanket with turbulence. As a result, residence time of fibrous fuels within the combustion chamber is increased, thereby arresting the fuel carry over. Innovative jack system arrangement (10), helps easy lifting of entire bed to a substantial amount for replacement of bearing and for maintenance.

WE CLAIM:
1. A multi fuel firing bed assembly comprising a drive system having means for growth of shaft in the drive couplings to take care of higher operation temperatures of moving bed and a second means for accommodating thermal expansion, the alignment of which is not disturbed even at elevated temperatures, and the usage of under bed air with higher temperature, integrated oil cooler, and locking system, said drive system being self lubricated and provided with lubricating ports and strategic arrangement so as to maintain smoother operation with reduced wear and tear.
2. A multi fuel firing bed assembly as claimed in claim 1, wherein an integrated oil cooler for the drive is adapted to maintain the oil temperature so as to prevent the thermal cracking of oil due to higher temperatures.
3. A multi fuel firing bed assembly as claimed in claim 1, wherein the said locking system is adapted to arrest the lateral and rotary movement, avoiding the damage to bearings and ensuring long trouble free life.
4. A multi fuel firing bed assembly as claimed in any of the preceding claims, hardened parts are used to ensure minimum wear, better durability, less maintenance time and cost.
5. A multi fuel firing bed assembly as claimed in claim 4, wherein scale resistant materials are selected for bed to extend life.
6. A multi fuel firing bed assembly as claimed in claim 5, wherein an innovative sealing arrangement is adapted to ensure effective distribution of combustion air to intended purposes by arresting the leakages to other areas, leakage of furnace buffs and arrests the ingress of air into the furnace thereby reducing excess air levels.
7. A multi fuel firing bed assembly as claimed in claim 6, wherein a highly preheated underbed air is used to obtain higher efficiency.
8. A multi fuel firing bed assembly as claimed in claim 1, wherein a strategic jack arrangement is adapted to ensure easy maintenance in a very short time.
9. A multi fuel firing bed assembly as claimed in claim 1, wherein a strategic underbed air entries is adapted on both sides of the firing system to ensure uniform distribution of air and to maintain uniform p across bed.
10. A multi fuel firing bed assembly as claimed in claim 1 and 9,
wherein arrangement is made of over fire air at three levels including air boxes with regulating dampers to combustion chamber (furnace) which curtails the unburnt carbon level and arrests the fuel carry over.

Documents:

1317-DEL-2004-Abstract-(05-02-2010).pdf

1317-del-2004-abstract.pdf

1317-DEL-2004-Claims-(05-02-2010).pdf

1317-del-2004-claims.pdf

1317-DEL-2004-Correspondence-Others (05-02-2010).pdf

1317-del-2004-correspondence-others.pdf

1317-DEL-2004-Description (Complete)-(05-02-2010).pdf

1317-del-2004-description (complete).pdf

1317-del-2004-description (provisional).pdf

1317-del-2004-drawings.pdf

1317-del-2004-form-1.pdf

1317-del-2004-form-18.pdf

1317-del-2004-form-2.pdf

1317-del-2004-form-3.pdf

1317-del-2004-form-5.pdf

1317-DEL-2004-GPA-(05-02-2010).pdf

1317-del-2004-gpa.pdf

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Patent Number

239453

Indian Patent Application Number

1317/DEL/2004

PG Journal Number

13/2010

Publication Date

26-Mar-2010

Grant Date

20-Mar-2010

Date of Filing

16-Jul-2004

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	MURUGAIYAN THANDAPANI	BHARAT HEAVY ELECTRICALS LIMITED BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.
2	RAMASAMY SESHARAJAN	BHARAT HEAVY ELECTRICALS LIMITED BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.

PCT International Classification Number

F22B 31/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA