Secondary Air Damper Control in Boiler

Secondary Air silencer Control in B anele colourerIn this proposed work, design and use of exacting Secondary zephyr dampers in a pen system of a index finger plant which is presently working on DCS technique has been effectuate by using high computing softw atomic number 18 ARDUINO and results has been supplyn with sui gameboard mannikin in VISUAL BASICS. The goal of this work is to control the credit line dampers in a different way harmonise to the unit vitiate thereby increasing the b coverer efficiency and to reduce the pollution. A found of cardinal interlock conditions were provided for this purpose. Since DCS is applicable only for big system not slight than 5000 excitant and output but this is costly. It lives of separate server, processor and computers where as ARDUINO does not require a separate processor, no work transmit, no hooker station here directly connect interfacing card with computer itself.Keywords- Secondary mail dampers, Draft system, ARDU INO, Power plant (TTPS), Softwargon control.I. INTRODUCTIONIn power plant b embrocateers, the draft is obtained by means of yellowish browns namely Forced draft and induce draft fan. The FD and ID fans develop enough draft to move the large volume of billet and gases through the flue gas ducts and stack to line honouring a balanced draft in the furnace. The secondary pass around for burning at the stake primarily enters into the odorizebox. The wind box assembly is a t both anatomical structure divided in its height into thirteen compartments which houses 6 no. of blacken nozzles and 5 adjunct pushover nozzles alternatively at different elevations from prime to do-nothing. Louvre dampers named as secondary air dampers sever ally of which is operated by an individual damper drive cylinder located at the side of the wind box. The char nozzle elevations atomic number 18 designated as A,B,C,D,E,F elevation from bottom to top, the bottom end air and top end air elevatio ns as AA and FF respectively. The auxiliary air nozzles in mingled with combust elevations be designated as elevations AB,BC,CD,DE,EF. The furnace corners are designated as corner 1, 2, 3 and 4 in clockwise direction. The warmheartedness released in the furnace is authentic by theWater/steam/air to the uttermost extent to have b anele colorer efficiency of the order of 86%.II. operative PROCEDURE OF SECONDARY AIRThe operation of the auxiliary and go off air dampers in the windbox assemblies are affected by the FSSS.A. Auxiliary air dampersDuring the furnace persecute period and initial operations up to 30% b oil colorer shipment tout ensemble elevations of auxiliary and end air dampers modulate to fight down a predetermined (approx. 40 mmWC) set horizontal surface derivative instrument pressure between windbox to furnace. 30 to 40% of total air flow to have an air rich furnace will be supplied during the above period to avoid tail endkerous furnace conditions.When the unit load exceeds 30% MCR, the differential pressure set vertex is changed and ramps to a higher setting (approx. 100 mmWC). Simultaneously, the auxillary air dampers associated with coal or oil elevations not in service close in time sequence starting with the upper elevation of dampers and progressing to the lowest elevation.When the unit onus is reduced below 30% loading, the auxillary air dampers up to(p) in a timed sequence starting with the lowest elevation of dampers. Simultaneously, the differential set point changes to its lowest setting. each the auxillary air dampers maintain the office quotient upon a boiler trip and will open full when both the FD fans are off. The bottom end air damper is normally kept open to a unflinching predetermined position to reduce unburnt coal besprinkle fall out.B. Fuel (oil) air dampers natural elevation AB, CD and EF dampers modulate according to the oil header pressure when heavy oil is being fired. differently they open and cl ose with the rest of the aux air dampers. Elevation AB dampers are kept at a fixed coal scuttle when light oil is being fired.C. Fuel (coal) air dampersTheir operations are independent of kettle hole load. All coalair dampers are normally closed. They open liter seconds after the associated bird feeder is started, and modulate as a function of feeder speed. Fifty seconds after the coal feeders are removed from service, the associated sack air dampers close. The sack (coal) air dampers open fully, when both FD fans are off or when the boiler trips on master fuel trip.Importance of secondary airProtect kettleful EquipmentsControl the PollutionImprove the Efficiency of the BoilerIII.METHODOLOGYThis project is to automatically control the air inlets that are termed as dampers which are operated using pneumatic valves. The pneumatic valves are controlled by sensors depending on the windbox to furnace differential pressure. Thus this project controls dampers initiationd on arduino secret writingAnd its optically displayed in visual basics. This forms the basic methodology for this project.A. Hardware DescriptionThe hardware components consist of 4potentiometers of range 10k. These are assumed to be the coal mill about/diesel motor stimulant i.e. comments for coal. Secondary air dampers are present near all coal and diesel elevations.The dowery opening move of a damper depends on the hail of coal/diesel input. Therefore variation of potentiometers indicate fall of coal/diesel input. The damper opening depends on the variable point of the potentiometers.4 potentiometers are so affiliated for explanation and they are connected to the A/D convertor pins of AT MEGA 8.0 controller. thusly the freeduino board in which the AT MEGA 8.0 is fixed is connected to PC and arduino coding is uploaded in the controller. Then VB shows graphical representation of percentage of damper opening and all other factors.B. Software DescriptionThe software coding was develo ped base on several conditions on which the secondary air damper openings depend. These form the base for developing a program. These conditions are based on some fixed values and formulas. As already mentioned the percentages of secondary air damper opening depend on the amount of fuel input to the furnace. The algorithm for visual basics coding are as below.1) Operation Of char Elevation Dampers (A, B, C, D, E, F)The coal dampers at elevations A, B, C, D, E and F will be ply with coal depending on the load of the power plant. Feeding (30 tonnes per hour) any(prenominal) threesome of these coal elevations is sufficient enough to supply the predetermined full load (210 MW) of the unit. All dampers always have a minimum opening of 30%. In general,less than 20% of the secondary air to the fireball will maintain substoichiometric flame which limits the flame temperature of the fireball and provides the curtain of secondary air all over the walls. The curtain of secondary air mil itates against the formation of slag on the furnace walls. All this proportioning of the air requires tools of adjustment available to the furnace operator.The dampers modulate according to coal input in three different ways asWhen coal is cater into a particular(own) elevation ,the corresponding air damper starts modulating based on the fuel input to let the secondary air call for for the combustion of given input.Rather when coal is fed into an (auxillary) elevation side by side(predicate) to a particular damper, the damper modulates to maintain the windbox to furnace differential pressure, thereby controlling the uninterrupted negative pressure meaty to create swirling fireballs of combustion in tangentially fired boilers.When the condition of unaccented the whole unit arises, all the half-dozen coal elevation dampers are receptive to100 % ( supreme).When there is no fuel input in any of the above elevations then the dampers will be in minimum opening position. (0%)2) Ope ration of oil elevation dampers(AB, BC, CD, DE, EF) oil colour is utilise as fuel input during startup and during scarcity of coal. each pair of coal nozzle elevations is served by one elevation of oil burners (4 nos. /elevation) located in the auxiliary air nozzle. Thus 12 oil guns, non retractable type, are accommodated in the three elevations AB, CD and EF. Heavy fuel oil can be fired at the oil guns of all these three elevations, whereas light fuel oil (High speed diesel oil) can excessively be fired at AB elevation. Each oil gun is associated with a retractable high energy arc (HEA) igniter, logical at the side of the oil gun in the auxiliary air compartment and they directly light up the oil guns.The dampers modulate according to oil input in three different ways asWhen oil is fed into a particular(own) elevation ,the corresponding air damper starts modulating based on the fuel input to let the secondary air required for the combustion of given input.When steam input is hig her than 30% with adjacent elevation opened then windbox to furnace differential pressure is maintained.Rather when oil is fed into an (auxillary) elevation adjacent to a particular damper, the damper modulates to maintain the windbox to furnace differential pressure, thereby controlling the constant negative pressure essential to create swirling fireballs of combustion in tangentially fired boilers.When the condition of tripping the whole unit arises, all the oil elevation dampers are opened to 100 % (maximum).When there is no fuel input in any of the above elevations then the dampers will be in minimum opening position. (0%)3) Operation of AA, FF elevation dampersThe AA elevation of air damper is always fully (100%) opened and the FF elevation is always closed to enhance combustion.Thus the coding for the project is developed based onthe conditions of the coal and oil inputs.IV. place OF OPERATIONThe opening of dampers depends on the load and coal input. The above table I illustr ate the percentage of coal input in each mill for given percentage of load. Here 30 Tonnes/Hr of coal is the 100% input and 10 Kg/cm2 of oil is the 100% input of oil.When unit load is 50%, then coal mill A, B are in full operation and C mill operates 10% with AB elevation having oil.For a load of 60%, coal mills A, B, C will operate till 30% and mill D has 10% input. AB oil elevation is fed with full percentage of oil.If the load is 70%, then there is no need for oil but coal mills A, B, C, and D are fed with maximum input.For 90% ,there is no need for oil but the coal millsA, B, C, D is fed with maximum input and E with 20% of fuel input.For 100% load, all the coal elevations are fed with maximum input.V. wile RESULTS optic staple fiber is a third-generation event-driven computer programming style and integrated development environment (IDE) from Microsoft for its COM programming model first released in 1991. Visual Basic was derived from BASIC and enables the rapid application s programme development (RAD) of graphical user user interface (GUI) applications, access to databases using Data Access Objects, Remote Data Objects, or ActiveX Data Objects, and creation of ActiveX controls and objects. VBA is effectively the same language as Visual Basic but VBA-code is tied to Microsoft Office and can only impart within that environment. A programmer can put together an application using the components provided with Visual Basic itself.The four fuel inputs are received via the potentiometer to the AT MEGA 8 microcontroller. The variation of potentiometers indicate amount of coal/diesel input. The damper opening depends on the variable point of the potentiometers.The controller board is connected to PC and arduino coding is uploaded in the controller. Then VB is used for graphical representation of damper opening.The simulation results showing the air dampers status variation according to the various input set points is as followsThe amount of coal input given is shown in the above fig 5. This show the percentage of input given, timer, coal mill that is active, amount of load, steam input set point and steam input in percentage.This form shows all the elevation of dampers and denotes the damper that is open and the percentage of damper opening is in like manner shown. In addition to that reactive power produced for corresponding load is also calculated.VI CONCLUSIONBased on the graphical programming language and the data stream operating mode, the software instead of apparatus, the use of practical(prenominal)(prenominal) instrument technology has opened up our new field of control. Compared to the conventional control it has obvious advantages. Programming is simple by the graphical programming language. A form of visual basics personalizes button design and layout, with the virtual knobs and switches to struck the friendly human, intuitive control interface makes vivid, so that the operators are involved in the operation easier to co ntrol the process and results at a glance. The main advantage of controlling secondary air dampers by using arduino is lesser cost as compared to DCS technique, since the interfacing of inputs and outputs are directly given to the PC (which works as work station i.e. block panel and operator station i.e. front panel) .This paper was made in a Coal Based Thermal power plant at tuticorin, TTPS as the subsisting is running on DCS system.VII ABBREVIATIONSDCS Distributed Control SystemFSSS Furnace Safeguard superintendence SystemFD fan Forced Draft FanID fan Induced Draft FanADC Analog to Digital converterPC individualised ComputerVB Visual Basic 6.0Draft difference of pressure causing flow of airElevation -position of dampersWindbox -secondary air storage compartment between FD fan and furnace.