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Boiler Controls & Instrumentation K Karthikeyan Manager Controls & Instrumentation BHEL, Tiruchirappalli

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Presentation on theme: "Boiler Controls & Instrumentation K Karthikeyan Manager Controls & Instrumentation BHEL, Tiruchirappalli"— Presentation transcript:

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2 Boiler Controls & Instrumentation K Karthikeyan Manager Controls & Instrumentation BHEL, Tiruchirappalli

3 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I INTRODUCTION PART I - BOILER PART 2 - INSTRUMENTATION PART 3 - CONTROLS

4 Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

5 Boiler C&I -Functions Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

6 Control systems engineering Instrumentation engineering Electrical systems engineering New product development Boiler Controls & Instrumentation Broad engineering activities Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

7 Proposal Engineering Contract Engineering Product Engineering Quality Assurance & Control Field Engineering Research & Development Boiler Controls & Instrumentation Functions Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

8 Proposal Engineering Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

9 Scope of Work Project Estimate Offer submission Offer evaluation by customer Award of contract Proposal Engineering Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

10 In summary, the purpose is to draw-up - Scope of Work - Project Estimate of the project. Deliverables : - Estimable quantity(BOM)- main and spares - Datasheets - Descriptive offers of packages & - Preliminary design sketches(P&IDs, GA). Boiler Controls & Instrumentation Proposal Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

11 Arrived based on a broad specification prepared by the customer/consultant. Individual system scope identified gets recompiled into a project scope of work. Project scope document includes scope of work, terminal points & exclusions Scope of Work Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

12 The typical scope covered in Boiler C&I discipline include – Furnace safeguard Supervisory system – Secondary Air Damper control system – Soot blower control system – Boiler area field instruments – Associated cable & accessories. – Electricals(MCC, elevator etc.) Scope of Work Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

13 Offer evaluation The offers get evaluated at the customer end. Customer awards the contract on a technically qualified bid with the lowest price. The award of contract is indicated by a Letter of Intent received from the customer. Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

14 Award of contract The offers get evaluated at the customer end. Customer awards the contract on a technically qualified bid with the lowest price. The award of contract is indicated by a Letter of Intent received from the customer. Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

15 Contract Engineering Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

16 Packages SG integral C&I(Trichy) Station C&I(PEM or customer)- in case of BTG or Turnkey SG integral electricals(Trichy) Station Electricals(PEM or customer)- in case of BTG or Turnkey Contract Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

17 Contract Engineering The role involves system level contract coordination for the boiler C&I area. Applicable PGMA List Sub Delivery check list. Boiler Contract Regular activity(BCR) schedule 00 PG list(erection documents). Applicable O&M documents. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

18 System Engg. Documents involved : Piping&Instrumentation Diagrams(P&IDs) Measurement & control recommendations Automatic control schemes Interlock & protection schemes Contract Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

19 P & I Diagram- Air & flue gas (portion) Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

20 Instrument schedule steam & water (sample) Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

21 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Product Engineering

22 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Product Engineering Detailed design of Boiler C&I products & systems Digital controls Analog controls Electrical systems & cables Field instruments Special instruments Actuators

23 Digital Controls Burner management system. Soot Blower control system Analog Controls Secondary air damper control system. Auxiliary PRDS control system. Product Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

24 Electrical systems Control supply panels LT Motor control centres Power distribution panels Field instruments Switches & gauges for Pressure,Level & temperature Thermocouples Flow elements Product Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

25 Flame scanner system Acoustic steam leak detection system. Electronic water level indicator. Closed circuit television system. Vibration monitoring system. Flue gas analysers. Steam and water analysers. Product Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Special instruments

26 Electrical and C & I engineering design Release of indents for C & I sub-delivery items. Evaluation of technical offers for bought-out items Technical Delivery Conditions (TDC) Product Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

27 Quality Control & Assurance Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

28 The role involves preparation/review of following activity w.r.t C&I products & systems Prepare Standard Quality Plans (SQP) Prepare Contract Quality Plans (CQP) Review/Approve Vendor Quality Plans (VQP) Issue Reference Quality Plans (RQP) Prepare Inspection Check Lists (ICL) Quality Control & Assurance Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

29 Performing inspection at vendor works for CI products & systems - bought-out items Review & dispose Site Action Requests on CI products & systems Quality Control & Assurance Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

30 Field Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

31 The role involves Providing technical support / trouble shooting of C&I products / system during - Erection & commissioning stage of project - Operation after handing over to customer Review & dispose Commissioning action requests Review & dispose Contract closing pending issues Visiting sites to ensure smooth progress of C&I site activity Field Engineering Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

32 Research & Development Boiler Controls & Instrumentation Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

33 Microprocessor based Gravimetric coal feeder controls - BHELFEED Microcontroller based Flame moniotirng system - BHELSCAN Acoustic steam leak detection system – BHELSONIC Electronic water level Indicator system- BHELVISION Research & Development Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I In-house developed C&I systems & products

34 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Boiler Basics

35 BOILER CLASSIFICATION Cycle Conventional (Rankine cycle) HRSG (combined cycle) Nuclear Circulation Natural, Controlled Once through Type of firing Corner Front Downshot FBC Stoker Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Fuels Oil Coal Gas End use Utility Industrial

36 BOILER CLASSIFICATION Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

37 BHEL BOILERS Power Boilers Up to 600 MW rating(Coal, oil and gas fired - Subcritical) Up to 800 MW - Supercritical Nuclear steam generators Up to 235 MW rating Industrial boilers Up to 450 Tonnes/hour rating Fertilisers, Petrochemical, Steel & Paper industries Wide range of fuels- Oil, Gas, BFG, Bagasse, Black liquor. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

38 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

39 Schematic of a boiler

40 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

41 Furnace & Circulation system Superheaters Reheaters Economiser Airheaters Fans Pulverisers Raw coal feeders Fuel firing system Sootblowers Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I UTILITY BOILERS - ESSENTIAL COMPONENTS

42 Natural circulation Controlled circulation Once through Circulation ratio : Mass rate of water fed to the steam generating tubes to the mass rate of steam generated. Natural circulation 6 Controlled circ 4 Once through 1 CIRCULATION SYSTEMS Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

43 BOILER CIRCULATION SYSTEMS Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

44 1. Axial –Impulse type - IGV Control. –Reaction type - Blade pitch Control. 2. Radial Inlet damper control, Variable speed control; Variable speed control by two speed motor, Hydraulic coupling or Variable frequency drive. Fans Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

45 Radial Fan Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

46 Axial Reaction Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

47 -Flow proportional to Speed -Flow proportional to (Impeller Dia) 3 -Head proportional to (Speed) 2 -Head proportional to (Impeller Dia) 2 Hence Variation in speed alters the performance Bharat Heavy Electricals Limited - Tiruchirappalli RADIAL FANS - SPEED CONTROL Boiler C&I

48 FANS IN BOILER - SCOPE Primary air fans - Dries & transports Pulverised coal Forced draft fans - Supplies Combustion air Induced draft fans - Sucks Flue gas out of furnace Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

49 MILL - GRINDS COAL Slow speed mills (Tube mills - 15 to 25 RPM) Medium speed mills (Bowl mill, Ball and race mill etc.- 50 to 100 RPM) High speed mills (hammer mills directly coupled to motor to 1000 RPM) Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

50 RAW COAL FEEDERS Volumetric - Rotary and drag link, Gravimetric – Endless belt type Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Scope : CONVEY RAW COAL TO MILL Types :

51 AIRHEATER Heat recovery equipment Extract heat from Flue gas to heat primary & secy. Air Regenerative type ( Rotating drive ) Tubular type Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Types :

52 SOOTBLOWERS Remove ash & slag from pressure part tubes Types Long retractable sootblowers - traverse & rotary motors Half retractable sootblowers- traverse & rotary motors Rotary blowers - rotary motor Wall blowers - traverse & rotary motors Furnace temperature probe - Used during boiler start up Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

53 Fuels : Coal Oil Gas H/C ratio Natural gas 0.3 Fuel oil 0.1 Coal 0.07 Calorific value (kcal/kg ) Gas 10000Oil 8000 Bituminous coal Lignite 2500 Coal burning methods " On grate" In suspension" Fluidised bed Three 'T's of combustion –Time –Temperature and –Turbulence. FUELS & COMBUSTION Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

54 Short period of time High temperature & Very turbulent flame. FUELS & COMBUSTION Rapid combustion Less turbulence and longer burning produces fewer nitrous oxide. In some cases combustion is delayed or staged intentionally to obtain fewer nitrous oxide or to obtain desired flame characteristics. Boiler C&I Bharat Heavy Electricals Limited - Tiruchirappalli

55 The amount of carbon and oxygen for complete combustion of Carbon are represented by the formula Carbon + Oxygen = Carbon di oxide C + O 2 = CO BTU/Kg C 12 Kgs + 32 Kgs = 44 Kgs. The formula for combustion of hydrogen is represented by Hydrogen + Oxygen = Water 2H 2 + O 2 = 2H 2 O BTU/Kg H 2 4Kgs + 32 Kgs= 36 Kgs COMBUSTION CALCULATIONS Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

56 An example of incomplete combustion reaction, Carbon + Oxygen = Carbon monoxide 2C + O 2 = 2CO BTU/Kg C 24Kgs + 32 Kgs = 56 Kgs With right conditions of time, temperature and turbulence, by adding more oxygen to the carbon monoxide, the carbon monoxide will further oxidise to carbon di oxide resulting in the second part of heat energy from the original carbon. Carbon monoxide + Oxygen = Carbon di oxide 2CO + O 2 = 2 CO BTU/Kg CO 56 Kgs + 32 Kgs = 88 Kgs COMBUSTION CALCULATIONS Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

57 The theoretical requirement of combustion is given by Kgs air/ Kgs of fuel =11.53C (H2 - O2/8) S, where C, H 2, O 2 and S are decimal equivalent to ultimate analysis % by weight. If flue gas oxygen content is known, Excess air (%) = K[21/(21-% Oxygen) -1] * 100, where K = 0.9 for gas, 0.94 for oil and 0.97 for coal. This formula is based on dry basis percentage oxygen. COMBUSTION CALCULATIONS Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

58 Boiler Instruments Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

59 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

60 First letter P-Pressure T-temperature F- Flow A- Analytical Succeeding letters A- Alarm I- Indicate R- Record Q- Integrate C- Control S- Switch T- tansmitter E- Element P- Pocket W- Well Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Instrumentation representation- ISA

61 Boiler Controls Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

62 Continuous control : Objective Enabling Automatic Operation. Optimising operating performance. On-Off control : Objective Supervise process operation for safety Prevent process from entering unsafe condition. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I BOILER CONTROLS

63 Auto control system Boiler Auxiliaries interlocks & protection system Furnace safeguard supervisory system (FSSS) Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

64 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Master demand Combustion and draft control Feed-water control Steam-temperature control Auto control system.

65 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Master demand 'Master demand' controls the boiler operation. Set from unit load demand or main steam header pressure control Master demand sets burners firing at a rate required for steam production and corresponding air flow demand

66 Objective : Fuel is consumed at a rate that exactly matches the Steam demand. Fuel is consumed safely, so that the energy is released without risk to plant, personnel or environment Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Combustion control Fuel flow control Air Flow Control Coal mill control

67 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Combustion control Air Fuel/Cross Limiting AIR CONTROL FTPTFT A AT PI AT PI AT PI f(x) Fuel FLOW STEAM HEADER PRESSURE AIR FLOW SP LO SELECTHI SELECT Fuel CONTROL Fuel Feed AIR DAMPER Air Feed 67

68 Mill uses primary air - For transporting coal from mill to furnace. To "dry" coal. Air flow to mill and mill outlet temperature are regulated using Hot air damper and cold air damper respectively Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Mill air flow and temperature control

69 Feedwater control Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I Objective : To supply enough water to the boiler to match the evaporation rate. Water level in the drum indicates amount of water in boiler Actual Steam Flow - Used to determine required feedwater during transient conditions when level may not be accurate. Difference between Actual steam flow and Actual Feedwater Flow is added to the level error to form the Feedwater demand. Feedwater demand drives the feed control station to adjust feedwater sa as to maintain the drum level to normal value.

70 Feedwater control Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

71 Objective: To maintain a constant steam temperature at turbine inlet despite large load swings. Basic methods : DESUPERHEATING (ATTEMPERATION) Fine spray of comparatively cool water droplets into the vapour to reduce steam temperature. BURNER TILT POSITIONING Raise/Lower the Fireball in the furnace by tilting burners upwards or downwards. Steam temperature control Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

72 Steam temperature control Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

73 Secondary Air Damper Control Maintains proper windbox air flow distribution 0 to 30 % unit load, all auxiliary dampers modulated to maintain windbox to furnace differential pressure Above 30% unit load, BMS closes elevations of auxiliary dampers that are not required for elevations of fuel currently in service Fuel air dampers are positioned on an elevation basis as a function of the corresponding coal feeder speed High windbox to furnace differential pressure opens all the secondary air dampers Two types of dampers – Fuel air dampers & Auxiliary air dampers Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

74 Cascade control used for Spray de-superheating loop MS temperature error establishes the set point for SH DESH outlet temp. SH DESH outlet temp. error positions the spray control valve such as to regulate the MS temperature within allowable limits. Burner tilt responds to the lower of SH or RH outlet temp. Spray control responds to the higher of SH or RH outlet temp. Steam temperature control Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

75 BOILER AUXILIARIES INTERLOCKS AND PROTECTION SYSTEM Scope : Sequence control of starting and protection & interlocking of boiler auxiliaries… – FD fans – ID fans – PA fans – Airheaters – Dampers – Valves Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

76 FURNACE SAFEGUARD SUPERVISORY SYSTEM ( FSSS ) This system takes care of interlocks required for starting, supervising the operating and safe shut down of the equipments connected with fuel firing system. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

77 Tangential Windbox Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

78 FURNACE PLAN CORNER DESIGNATION FRONT WATER WALL SECONDARY AIR 2 C E R N O R - 1 C E R N O R - 4 C E R N O R - 3CE R N O R - Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

79 Fireball –Tangential Firing Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

80 CAUSES OF FURNACE EXPLOSIONS –An interruption of Fuel or Air supply or Ignition energy to the burners, sufficient to result in momentary loss of flames, followed by restoration and delayed re-ignition of an accumulation. –Fuel leakage into an idle furnace and the ignition of the accumulation by a spark or other source of ignition. –Repeated unsuccessful attempts to light-off without appropriate purging, resulting in the accumulation of an explosive mixture. –The accumulation of an explosive mixture of fuel and air as a result of loss of flame or incomplete combustion at one or more burners in the presence of other burners operating normally or during lighting of additional burners. –The accumulation of an explosive mixture of fuel and air as a result of a complete furnace flameout and the ignition of the accumulation by a spark or other ignition source, such as could occur where attempting to light a burner(s). –Purging with an airflow that is too high, which stirs up combustibles smoldering in hoppers. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

81 CAUSES OF FURNACE IMPLOSIONS –A mal-operation of the equipment regulating the boiler gas flow, including air supply and flue gas removal, resulting in furnace exposure to excessive induced draft fan head assembly. –The rapid decay of furnace gas temperatures and pressure resulting from either a rapid reduction in fuel input or a master fuel trip. –A combination of the two conditions indicated in a, b above has resulted in the most severe furnace implosion incidents. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

82 FUNCTIONS OF FSSS 1.FURNACE PURGE SUPERVISION 2.SECONDARY AIR DAMPER MODULATION AND ON-OFF CONTROL AND SUPERVISION 3.IGNITOR ON-OFF CONTROL AND SUPERVISION 4.LIGHT OIL ON-OFF CONTROL AND SUPERVISION 5.HEAVY OIL ON-OFF CONTROL AND SUPERVISION 6.PULVERIZER AND FEEDER ON-OFF CONTROL AND SUPERVISION 7.FLAME SCANNER INTELLIGENCE AND CHECKING 8.BOILER TRIP PROTECTION. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

83 F - FURNACE S - SAFEGUARD S - SUPERVISORY S - -SYSTEM FSSS ENSURES SAFE FURNACE OPERATING CONDITIONS DURING START UP LOW LOAD OPERATION SHUT DOWN. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

84 SOME OF THE PRECAUTIONARY MEASURES TO ACHIEVE SAFE AND RELIABLE OPERATION FURNACE SHOULD BE PURGED BEFORE LIGHT UP ADEQUATE IGNITION ENERGY TO EACH BURNER ADEQUATE AIR SUPPLY TO EACH BURNER TO AVOID FLAME OUT OPTIMUM FURNACE PRESSURE CORRECT AIR TO FUEL RATIO Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

85 FUNCTIONAL DIVISION OF LOGICS UNIT LOGIC ELEVATION LOGIC CORNER LOGIC Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

86 TYPICAL CONDITIONS FOR FURNACE PURGE: Heavy fuel oil trip valve closed. Heavy fuel oil nozzle valves closed. Light fuel oil trip valve closed. Light fuel oil nozzle valves closed. Flame scanners on each elevation indicate no flame. Air flow greater than 30% and less than 40% All pulverisers off. All feeders off. Pulveriser outlet gates closed. All hot air gates closed. All cold air dampers not greater than 5° open. Both PA fans off. No boiler trip existing. –All auxiliary air dampers modulating. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

87 BOILER TRIP COMMAND IS INITIATED BY LOW OR HIGH DRUM WATER LEVEL BOTH I.D OR F.D ARE OFF LOW OR HIGH FURNACE PRESSURE REHEATER PROTECTION TRIP TURBINE LOSS OF ALL FUEL TRIP LOSS OF UNIT D.C POWER LESS THAN FIRE BALL AND LOSS OF AC AT ANY ELEVATION MANUAL TRIP UNIT FLAME FAILURE TRIP INSUFFICIENT PRIMARY AIR Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

88 BOILER TRIP COMMAND RESULTS IN STOPPAGE OF ALL FUEL INPUTS BY TRIPPING 1.ALL PULVERIZERS 2.ALL FEEDERS 3.ALL OIL GUNS 4.ALL IGNITORS IT CLOSES 1. IGNITOR 2.LIGHT OIL TRIP VALVES 3.HEAVY OIL TRIP VALVES Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

89 Scanner Fan logic Scanner duct to furnace DP when low initiates a Scanner air fan -A run command If DP value remains low for more than five seconds, scanner air fan -B run command is issued. If DP condition is low even after 10 seconds Loss Of Scanner Cooling Air alarm is generated Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

90 Seal Air Fan Control When either Primary Air Fan is on, seal air fan A is automatically placed in service. If either Primary Air Fan is on & Seal Air Header/Cold Air Duct DP is low, the seal air fan is auto started. When both seal air fans are on and the Seal Air Header/Cold Air Duct DP is not low,either seal air fan can be stopped manually. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

91 PULVERIZER STARTING PROCEDURE START PULVERIZER ON FEEDBACK OPEN HOT AIR GATE WAIT TILL PULVERIZER COMES TO TEMPERATURE ( 140°F ) START FEEDER ( AT MINIMUM FEEDER SPEED ) COAL FLOW INDICATOR OR PULVERIZER AMPERE ( ( WITH IN 5 SECONDS ) FIFTY SECONDS FEEDER SPEED RELEASED TO AUTOMATIC CONTROL FUEL AIR DAMPER OPENED FUEL AIR DAMPER MODULATED TO AUTOMATIC CONTROL. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

92 PULVERIZER START REQUIREMENTS AIGNITION ENERGY AVAILABLE B.ADEQUATE PRIMARY AIR C.D.C POWER AVAILABLE D.LOCAL PULVERIZER CONDITION SATISFACTORY E.IF NO OTHER FEEDER IS WORKING FUEL AND AIR NOZZLE TILTS PLACED IN HORIZONDAL CONDITION. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

93 CONDITIONS ( LOCAL ) TO BE SATISFIED TO START RESPECTIVE PULVERIZER A.DISCHARGE VALVE OPEN B.SEAL AIR VALVE OPEN C.COLD AIR DAMPER OPEN D.PULVERIZER DAMPER OUTLET LESS THAN 200°F E.FEEDER INLET GATE OPEN F.TRAMP IRON HOPPER VALVE OPEN. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

94 PULVERIZER IGNITION ENERGY AVAILABLE A MINIMUM OF 3 OF THE 4 LIGHT OIL OR HEAVY OIL NOZZLE VALVE OF THE ELEVATION JUST ABOVE OR BELOW, ARE OPEN OR BOILER LOADING IS GREATER THAN 30% AND PULVERIZER JUST ABOVE OR BELOW IS IN SERVICE AT GREATER THAN 50% LOADING. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

95 MILL OUTLET TEMPERATURE CONTROL HIGH PULVERIZER OUTLET TEMPERATURE (ABOVE 200°F ) WILL OPEN COLD AIR DAMPER AND CLOSE HOT AIR GATE. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

96 FEEDER CONTROL A.FEEDER RUNS AT MINIMUM SPEED UNTIL INITIATING CONDITION IS CORRECTED, AT WHICH TIME THE FEEDER WILL BE RETURNED TO CONTROL. A. PULVERIZER BOWL DIFFERENTIAL HIGH. B. PULVERIZER AMPS. ABOVE MAXIMUM SET POINT. B.LOSS OF COAL FLOW AND LOW PULVERIZER CURRENT WILL TRIP THE FEEDER, OPEN COLD AIR DAMPER AND CLOSE HOT AIR GATE. AFTER CORRECTIVE ACTION THE HOT AIR GATE IS OPENED AND FEEDER IS RESTARTED. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

97 CONDITIONS FOR A PULVERIZER TRIP PULVERIZER DISCHARGE VALVE NOT OPEN LOSS OF UNIT DC POWER (FOR MORE THAN 2 SECONDS) PULVERIZER IGNITION PERMIT NOT SATISFIED AND SUPPORT IGNITION IS REQUIRED. BOILER TRIP PRIMARY AIR FAN TRIP Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

98 PULVERIZER SHUT DOWN SEQUENCE START ASSOCIATED OIL ELEVATION REDUCE FEEDER SPEED TO MINIMUM CLOSE HOT AIR GATE PULVERIZER OUTLET TEMPERATURE IS 120°F STOP FEEDER WAIT FOR 2 MINUTES STOP PULVERIZER FURNACE STABILIZES ASSOCIATED OIL LEVEL SHUT DOWN. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

99 PULVERIZER SHUT DOWN START ASSOCIATED OIL ELEVATION REDUCE FEEDER SPEED TO MINIMUM CLOSE HOT AIR GATE PULVERIZER TEMPERATURE IS 120°F STOP FEEDER TWO MINUTES STOP PULVERIZER FURNACE STABILIZES SHUT OFF ASSOCIATED OIL ELEVATION. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

100 ARRANGEMENT OF SYSTEM FSSS - MAJOR PARTS LOGIC CABINET CONSOLE INSERT SECONDARY AIR DAMPER PANEL MILL PANEL FIELD EQUIPMENTS CUSTOMER SUPPLIED INTERFACE EQUIPMENT. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS

101 Oil gun start sequence HEA Advances Atomising valve opens Corner oil valve opens HEA sparks Flame scanner picks up flame HEA retracts Corner valve closes if flame is not sensed. Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I

102 Bharat Heavy Electricals Limited - Tiruchirappalli Boiler C&I FSSS – Oil gun start up timing sequence

103 THANK YOU


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