|Title of Invention||
"ADVISORY ENGINE FOR MONITORING PERFORMANCE AND EFFICENCY OPTIMIZATION OF A STORKER FIRED BOILER"
|Abstract||"An advisory engine for monitoring the performance and efficiency optimization". An advisory engine for monitoring the performance and efficiency optimization characterize of a stoker-fired boiler producing steam having a combustion chamber, a stoker for supporting a solid fuel bed, said stoker disposed at bottom of combustion chamber for providing an energy source for combustion characterize in that the engine comprising a distributed control means (5) operably connected to a processing apparatus (6), the processing apparatus being operable to receive the operational data via the distribution control means and to compare online the received data with a pre-stored data representing benchmarked operational parameters of the boiler to indicate the corrective measures initiatable by the operator. Fig.l|
|Full Text||T his invention relates to stoker fired boilers and their operation management systems. A stoker fired boiler is a special type of boiler wherein a moving bed is placed at the bottom of the furnace (combustion chamber) of the boiler. The fuel to be burnt is fed and spread at one end of the moving bed. The speed of the moving bed is
varied to suit the fuel characteristics / operational requirements. Stoker fired boilers are popularly employed worldwide by sugar industries, paper/pulp industries and many other industries which require steam and / or power for its operationetc. A typical feature of the stoker fired boiler is that it is adept in burning a variety of fuels, from the most
readily burnable" coals to "hardly burnable" biomass and municipal waste. Since stoker fired boilers are put to use with all sorts of unique and varied fuel options, optimizing their performance is always a challenging task. Great quantum of time and efforts are spent worldwide to arrive at "systems" or devices that will save the tough job of critical optimization of the operating factors and performance parameters.
I he invention relates to specifically to an advisory system that helps the operator of the stoker-fired boilers in monitoring the operating conditions and track critical parameters. 1 urther, the system also has provisions to compare the actual operating conditions (parameters) like
boiler outlet steam flow, steam pressure steam temperature
flue gas temp, leaving economizer
flue gas temp, entering air heater
flue gas temperature leaving air heater
air temperature entering AH
air temp, leaving air heater
online (in real time) to pre-determined sets of 'operating conditions" that pertains to "best practice" or "benchmarked guidance value". Based on such comparisons, the system also further generates "expert advice" or strategic corrective actions, course-corrections etc., to optimize the operation. The system is user friendly and programmable such that the logic and methodology of making "expert advise" is fully under the control of the concerned system analyst.
Prior art; Presently advisory systems for performance monitoring and optimization of stoker fired boilers is not available in the market. Packages which work out the efficiency of a boiler ordine are available and they work in conjunction with distributed control system (DCS). These packages calculate and display the efficiency at which a boiler operates at any instant. They do not indicate whether the boiler operates at the optimum efficiency and if not, what are measures (corrective actions) to be taken by the operating personnel to achieve the optimum efficiency. The above shortcomings are addressed by the presently developed advisory system.
To find out the details of existing state of art, a thorough search was conducted. The results of search indicates availability of only one patent on the topic related to stoker boilers in US Patent 4362269.
US Patent: 4362269 titled "Control system for a boiler and method therefor" discloses a method and system for controlling the combustion of coal or bark in a stoker boiler or black, liquor in a recovery boiler to provide operation at a maximum efficiency. Control loops are provided for primary or undergrate air and secondary or overfire air.
fhe description given in the above referred patent is for a method and system for controlling the combustion of coal or bark in a stoker boiler or black liquor in a recovery boiler to provide operation at maximum efficiency.
The invented design covered in this specification is entirely different from the above patent since it pertains to an advisory system for performance monitoring and optimization of stoker fired boilers used in a sugar plant and firing coal and / or baggase as fuels.
Summary of invention:
rhe innovative aspect of the invention is that the apparatus and method is based on the use of fundamental relationships of heat transfer. Further, continuously the current actual performance of the boiler is evaluated and compared with the predicted performance evolved based on the use of above said fundamental relationships. Variations in the boiler parameters under transient conditions have been taken care to avoid unnecessary
adjustment on operation. The advisory system provide apt guidance in a user fi-iendly format to plant personnel. This advisory system also helps to train the operating personnel.
Objectives of the invention:
The present invention is directed to an advisory instalment for a stoker boiler to optimize its performance for achieving maximum efficiency. The system provides histogram & trending facility for monitoring current and past performance of the boiler. Based on the current operation of the boiler, the system provides guidance message to the operator in a user-friendly format. Following the guidance message, the operator can take initiative to adjust the boiler for achieving maximum efficiency under any operating condition.
Detailed description of the invention with reference to numbered parts:
The invention is specifically made for stoker fired boilers. For the optimization system, inputs like steam flow, quantity of fuel fired, steam temperatures, flue gas temperatures etc., are taken from various field instruments through Distributed Control System (DCS). The optimization software package which enables optimum operation of the boiler, is loaded in a typical commercially available personal computer. This computer is connected through suitable bus connection with DCS. The optimization system package calculates various boiler parameters online for a specific fuel say coal or baggase or lignite or others. Some of the calculated parameters are compared with actual measured value. If the deviation is more than acceptable limits set (different values for different parameters, which can be adjusted to suit the optimization required) the system displays
advisory and diagnostic remarks about the possible reasons for the deviation and suggest remedial measures. Based on this, operator can take corrective actions to obtain optimal boiler efficiency.
The system has modules developed using Microsoft Visual Basic® and it runs on Windows ®OS. MS Excel is used to accept inputs for this program. These inputs are received from the plant's Distributed Control Syslem (DCS). Visual Basic is used as front-end tool and it retrieves input data from MS excel and calculate various boiler parameters at various stages, To calculate enthalpy of water and steam at various pressures, temperature of steam 32. dll file has been used and for specific heat of gas and air, user-defined functions are used. These user-defined functions are called in at various stages of the program execution.
The advisory system helps the operator of stoker fixed boilers in monitoring the operating conditions, track critical parameters, compare the present operating conditions with the benchmarked condition and provide expert advice, figure 1 attached indicates the various numbered parts. The inputs to the advisory system are taken from various field equipments (1) through Junction boxes (2), marshalling JB (3). cables (4) to the distributed control system (5). The junction boxes marshalling JBs and cables facilitate connection of field equipments (process switches, RFDs, Thermocouples etc.) located in different parts of the boiler to the distributed control system located in the control room. The optimization software package is loaded in a PC (6). The PC is connected to DCS (5) through suitable bus communication cable (9). A power distribution board (8) facilitates distribution of 230V AC power supply to the DCS and the PC through suitable cable (7).
Salient features of this software package are:
• Dynamic monitoring of the field signals
• Analysis of data and customized report generation
• Histogram & trending facilities
• Display of guidance message to the operator
• Facilities to interface with other PLCs/DCS
IVlain advantages of the software package are:
• Displays various important boiler parameters
• Analysis the nature of a running boiler at any load
• Provide guidelines for optimum operation of boiler
1. An advisory engine for monitoring the performance and efficiency optimization of a stoker-fired boiler producing steam having a combustion chamber, a stoker for supporting a solid fuel bed, said stoker disposed at bottom of combustion chamber for providing an energy source for combustion characterize in that the engine comprising a distributed control means (5) operably connected to a processing apparatus (6), the processing apparatus being operable to receive the operational data via the distribution control means and to compare online the received data with a pre-stored data representing benchmarked operational parameters of the boiler to indicate the corrective measures initiatable by the operator.
2. The engine as claimed in claim 1 wherein the solid fuel is coal, biomass, bagasse and municipal waste.
3. The engine as claimed in claim 1 wherein the parameters used in the boiler for monitoring are boiler outlet steam flow, steam pressure, steam temperature, fuel flow, flue gas temperature leaving economizer, flue gas temperature leaving air heater, air temperature entering air heater and air temperature leaving air heater.
4. The engine as claimed in claim 1 wherein the said boiler is of recovery type.
5. The engine as claimed in claim 1 wherein junction boxes (2) marshalling JBs (3) and cables (4) facilitate connection of filed equipments (1) located in different parts of the boiler to the DCS (5) located in the control room.
|Indian Patent Application Number||598/DEL/2004|
|PG Journal Number||12/2010|
|Date of Filing||25-Mar-2004|
|Name of Patentee||BHARAT HEAVY ELECTRICALS LIMITED|
|Applicant Address||BHEL HOUSE,SIRI FORT,NEW DELHI-110 049,INDIA|
|PCT International Classification Number||F23N 1/00|
|PCT International Application Number||N/A|
|PCT International Filing date|