Title of Invention

AN AUTOMATED SMART WALL BLOWING SYSTEM (SWBS)

Abstract This invention relates to an Automated Smart Wall Blowing System(SWBS) comprising an electrical/electronics system having hard wares such as water wall mounted heat flux sensor and signal conditioner, flow transmitter/current converter, logic panel and MMI panel interfaced with the conventional soot blowing hardware characterized by additional pre programmed logics software with which the sequential starting and stopping of the wall blowers being activated by the high and low set points of super heater spray flow respectively and specific blowers where near by absorbed heat flux values below the predetermined value being operated considering permissive soot blowing header steam pressure, temperature and response time and by exercise of said, logics, the furnace heat absorption being maintained at optimum levels and consequently the excursions in furnace gas outlet temperatures and Super heater/Re heater sprays being automatically controlled within a range without operator's intervention and thus improving overall boiler performance.
Full Text FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to an improved/smart wall blowing system for maintaining furnace heat absorption at optimum in any fuel fired boilers and wall blowing only in those areas where deposition is high.
The present invention particularly relates to wall blowing in any fuel fired boilers which would operate need-based and automatically, primarily starting and stopping the wall blowing system to maintain the furnace water wall heat absorption within optimum range and secondarily for skipping wall blowing wherever the ash deposit intensity is not high as indicated by heat f!ux sensors mounted between wall blowers.
The radiation (Furnace and platen super heater) and convection zone heat transfer surfaces (other super heaters, economizers etc) of a boiler are designed according to the established practice, to absorb proportionately the heat released on combustion of fuel such that various functions such as water preheating (economizer), steam generation (water wall), steam super heating (LTSH, Platen SH and Final SH), steam re-heating and air heating are carried out optimally.
The boiler furnace, where the fuel is burnt, absorbs the maximum of the heat released. Impurities present in the fuels cause deposits on boiler water wall surfaces resulting in the reduction of furnace heat absorption. The pattern, nature and rate of deposition vary along various zones of the furnace. Due to the combined effects of differing heat release rates of fuels, and varying compositions, and rates of depositions on water walls and further defending on boiler load, mill combinations, tilt etc, the net furnace heat absorption could vary from the predetermined value dynamically form time to time.
If the furnace heat absorption is lowered, the furnace outlet gas temperatures go up resulting in increased SH/RH sprays, increased metal temperature as well increased Nox levels due to higher furnace temperatures. The cycle efficiency of power plant suffers on increases in sprays, viz. with increase in re-heater spray in 210 MW designs and with increase in both SH/RH
sprays in 500 MW designs. On the outer hand, if furnace heat absorption increases, the furnace outlet gas temperature and consequently SH/RH steam temperatures fall short of to predetermined value resulting in lower efficiency. Due to fluctuating fuel characteristics and due to changes in operational requirements such as varying the mill combinations for pulverised coal firing and changing the burner tilt to achieve desired boiler parameters, most of the boilers experience varying degrees of sprays or low steam temperature condition. Hence, maintaining furnace heat absorption optimally is a key operational requirement under varying boiler operational conditions to maintain efficient boiler performance.
PRIOR ART
The device developed earlier by this applicant and as described in patent specification 451 DEL 2001 and 510 DEL 2001 maintains the furnace water wall heat absorption at optimum levels by operating the pre programmed set of wall blowers activated by the signals such as Super heater spray exceeding "High" set points and permissive such as soot blowing header steam temperature, etc and discontinuing operation of next wall blow when Super heater spray level reduces below the low set point, so that referred boiler parameter variations are minimized and the overall boiler performance is improved.
During the above sequence only those blowers are activated for which the heat flux level as sensed by the heat flux sensors ! located in between wall blowers is below the set value. In this system wall blowers are operated one wall after another wa!l, in, staggered manner, but in sequence, as demanded by the system.
The Device/System for maintaining furnace heat absorption and improved wall Blowing System developed earlier by this applicant in patent specification 451/DEL/2001 and 510/DEL/2001 respectively, operating hitherto requires operators'intervention to change 'High'and \ow' set points of super heater spray whenever an operational change viz., change in mills, change in burner tilt, change in combustion air flow and change in fuel quality takes place. Such a system requires continuous operator intervention distracting the attention of operating engineers form the core boiler operation.
The Device/System for maintaining furnace heat absorption and improved wall Blowing System developed earlier by this applicant (vide patent specification 451 DEL 2001 and 51Q DEL 2001 respectively,) requires operators' intervention to change 'Low'set point of absorbed heat flux whenever an operational change viz., change in mills, change in burner tilt, change in combustion air flow and change in fuel quality takes place. Such a system requires continuous operator intervention distracting the attention of operating engineers form the core boiler operation.
As such the Indian patent application number 451/DEL/2001 & 510/DEL/2001 illustrate a method by which manual setting of high and low set point for super heater spray levels for actuating the wall blowers in preprogrammed sequence operation or skipping a particular blower based on absorbed heat flux level.
Hence the prior are does not contain a teaching that the super heater spray level signal trends and absorbed heat fiux signals can be utilized for automatically selecting set points as the SH spray and absorbed heat flux trends change in response to operational variations.
Arriving at the appropriate set points suiting the operational changes is difficult and requires frequent attention. Even such changes carried out manually, are not valid for long duration continuous operation.
It is an object of the present invention to mitigate the above drawbacks of the earlier system to improve and automate the process elimination operator intervention..
A further object of the present invention is for maintaining net furnace water wal! heat absorption at an optimum range by activating the operation and stopping of the wall blowers by pre-selected signals such as, Super heater spray flow and heat flux as absorbed by the water wall by automatically updating the set points, irrespective of the changes in boiler operating conditions.
A further object of this invention is to prevent the wall blowing during boiler going to low load conditions.
A further object of the present invention is to provide shift wise blower operation data for information and analysis by operating engineers
SUMMARY OF THE INVENTION
This invention is applicable to any system working based on set point control system using the variation in absorbed heat fiux and spray flows as set point for actuating wat! blowers. It is also an improvement applicable to the Device/System for maintaining furnace heat absorption and improved Wall Blowing System developed (Indian
patent application numbers 451/del/2001 & 510/del/2001). The
changes in the logic diagram (Fig.2 of patent application 510/DEL 2001) are shown in Fig.l of this patent specification.
The applicants have developed a new system, applicable to any system working on set point based operation, having the following embodiments:
L The system developed by the applicants automatically changes
the set point for actuating blowers as and when an operational
change takes place in the boiler. The super heater spray flow
values collected in averaged for every pre set time and the new
super heater spray high and low set points are computed and
further blowing sequence gets automatically started/stopped as
per the updated set points. The computed set points are
clipped or restricted to a predetermined High and Low spray
levels based on unit operating experience. The interval for
averaging the spray flow and the clipping levels of High and
Low set points are user configurable through the software buitt-
in,
2. The system developed by the applicants automatically changes
the heat flux set point for actuating blowers as and when as
operational change takes place in the boiler. The absorbed
heat flux values of every sensor are averaged for every pre set
time immediately after the operation of each wa!! blower to
compute the index for set point for that wall blower for the
next cycle, automatically to operate/not operate as per the
updated set point.
3. To avoid frequent blowing of soot/wall blowers, a pre
programmed and user configurable delay system is built-in at
the end of completing the scanning of all soot/wall blowers.
4. The improved SWBS ensures non operation of wall blowers
during boiler going to low load conditions (low main steam
flow)
5. The improved SWBS provides shift wise blower operation data
for a period of one week for information and analysis by
operating engineers. The above blower operation data is stored
as a file and a new file is created subsequently.
6. The above improved device / system can be incorporated in all
new soot blowing installations in total and also as an add- on
system to existing soot/wall blowing with much operational
flexibility.
7. The invention is applicable to any system operating based set
points
In the improved/soot/wall blowing system of the present invention, the super heater spray flow and absorbed heat flux set points of HIGH/LOW are calculated and set automatically without operator intervention for ail changes that take place in the operating conditions of the boiler, viz, mil! combinations, load, tilt, etc. The wall blowing cycle of operation goes through a preprogrammed delay period. The system operates the wall blowers in groups is improved with non-operation of blowers during boiler low load and improved with statistics on blower operation
In addition, the computed set points are clipped or restricted to a predetermined High and Low spray levels based on unit operating experience. The sampling time, interval for averaging the spray
flow and the clipping levels of High and Low set points are user configurable through the software built-in for the improved soot/wall blowing system. To avoid frequents blowing of soot/wall blowers, a pre-programmed and user configurable delay system in built-in at the end of completing the scanning of all soot/wall blowers.



WE CLAIM;
1. An Automated Smart Wall Blowing System(SWBS) comprising an electrical/electronics system having hard wares such as water wall mounted heat flux sensor and signal conditioner, flow transmitter/current converter, logic panel and MMI panel interfaced with the conventional soot blowing hardware characterized by additional pre programmed logics software with which the sequential starting and stopping of the wall blowers being activated by the high and low set points of super heater spray flow respectively and specific blowers where near by absorbed heat flux values below the predetermined value being operated considering permissive soot blowing header steam pressure, temperature and response time and by exercise of said, logics, the furnace heat absorption being maintained at optimum levels and consequently the excursions in furnace gas outlet temperatures and Super heater/ Re heater sprays being automatically controlled within a range without operator's intervention and thus improving overall boiler performance.
2. An automated SWBS as claimed in claim 1 wherein the said system changes the spray flow predetermined actuating blowers change takes place in the boiler, the super heater spray flow values collected is averaged for every pre set time to compute the new super heater spray high and low set points, whereby blowing sequence automatically started/stopped as per the updated set points.
3. An automated SWBS as claimed in claims 1 and 2 wherein said
system based on set point control system using variation in
absorbed heat flux and spray flows as set point for actuating wall
blowers automatically changes heat flux set point for actuating
blowers as and when an operational change takes place in the
boiler, the absorbed heat flux values of every sensor are averaged
for every pre set time immediately after the operation of each wall
blower to compute the index for set point for that wall blower for
the next cycle, automatically to operate/not operate as per the
updated set point.
4. An automated SWBS as claimed in anyone or claim 1 to 3
completing mechanical electrical and electronic hardware and
embedded software integrated with a data acquisition and display
system.
5. An automated SWBS as claimed in anyone or claim 1 to 4, wherein Super Heater Spray Flow (SHSF) is prescribed with set point on completion of every group of wall bowing, and when SHSF reaches below low set point, the wall blowing sequence is halted and soot blowing steam header valve gets closed automatically and waits for SHSF to exceed the set value for activating stating the sequence again.
6. An automated SWBS as claimed in anyone or claim 1 to 5 wherein said software is provided with inbuilt means to alarm and call for operator intervention only under abnormal situations.
7. An Automated Smart Wall Blowing System (SWBS) substantially herein described and as illustrated in the drawing accompanying the Provisional Specification.


Documents:

1036-DEL-2003-Abstract-(05-02-2010).pdf

1036-del-2003-abstract.pdf

1036-DEL-2003-Claims-(05-02-2010).pdf

1036-del-2003-claims.pdf

1036-DEL-2003-Correspondence Others-(08-11-2011).pdf

1036-DEL-2003-Correspondence-Others (05-02-2010).pdf

1036-DEL-2003-Correspondence-Others-(15-11-2010).pdf

1036-del-2003-correspondence-others.pdf

1036-del-2003-correspondence-po.pdf

1036-DEL-2003-Description (Complete)-(05-02-2010).pdf

1036-del-2003-description (complete).pdf

1036-del-2003-description (provisional).pdf

1036-del-2003-drawings.pdf

1036-DEL-2003-Form-1-(15-11-2010).pdf

1036-del-2003-form-1.pdf

1036-del-2003-form-19.pdf

1036-DEL-2003-Form-2-(15-11-2010).pdf

1036-del-2003-form-2.pdf

1036-del-2003-form-3.pdf

1036-del-2003-form-4.pdf

1036-del-2003-form-5.pdf

1036-DEL-2003-GPA-(05-02-2010).pdf

1036-del-2003-gpa.pdf


Patent Number 244922
Indian Patent Application Number 1036/DEL/2003
PG Journal Number 53/2010
Publication Date 31-Dec-2010
Grant Date 24-Dec-2010
Date of Filing 22-Aug-2003
Name of Patentee BHARAT HEAVY ELECTRICALS LTD.
Applicant Address BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.
Inventors:
# Inventor's Name Inventor's Address
1 RAMAN KALIAPPAN BHARAT HEAVY ELECTRICALS LTD., BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.
2 RAMASAMY DHANUSKODI BHARAT HEAVY ELECTRICALS LTD., BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.
3 VENKATARAMAN NIRMALA BHARAT HEAVY ELECTRICALS LTD., BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.
4 SHANMUGAM KALYANASUNDARAM BHARAT HEAVY ELECTRICALS LTD., BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.
5 KRISHNAMURTHY NANDAKUMAR BHARAT HEAVY ELECTRICALS LTD., BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.
PCT International Classification Number G06K 19/07
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA