Hru control system upgradation and supplementary firing system (4) (1).pptx

Heat recovery unit

1. Hru control system upgradation and supplementary firing system BY- KULDEEP JAISWAL (GET INST. OFFSITE)

2. HEAT RECOVERY UNIT HRU stands for Heat Recovery Unit and it uses Flu gases(460-480 degC and 76kg/sec) generated from GT exhaust to recover the heat and generate the HP Steam for multiple use . The HRU is of compact design and it consists of Burner Management System to heat up the flu gases and use them to generate the HP steam. The BMS consists of Four vertical Burners in it which are used in Supplementary Firing System to heat up the Flu gases.

3. Burner management system The boiler along with all heat recovery modules, burners and firing control system is designed and erected by M/s Burmiester Wain Energy, Denmark . A BMS is a type of control system that manages the combustion process in industrial boilers and furnaces. Its main function is to ensure safe and efficient combustion of fuel in the furnace, and to regulate the various parameters such as fuel flow, temperature and pressure. The BMS typically consists of a combination of hardware and software components, including sensors, control valves, actuators and a control panel or computer that monitors and adjusts the combustion process in real time. The System is designed to optimize the combustion process, reduce emissions and minimize the risks of fire or explosions.

4. BURNER DESIGN DATA 1.) Main Burner:- Make- Smitsvonk, Holland Burner capacity- 23.6MW(20.3Gcal/hr) Fuel type- Natural Gas No of Ignition Burners- 1 per burner No of scanners- 1 per burner Ng pressure at burner- (0.15-3)kg/cm2. Ng flame length- 4 to 6m

5. Burner design data 2.) Ignition Burner:- Make- Smitsvonk, Holland Type- NG fired with spark ignitor Capacity- 0.15MW(0.13 gcal/hr), 0.004 Nm3/hr NG NG pressure- 1.5 to 2.1 kg/cm2g Use- 1per burner To avoid false signals to the UV scanner, the ignition spark generator will be switched off automatically once the ignition burner is on.

6. BURNER DESIGN DATA 3.) Flame Scanners:- Each burner has been provided with one UV flame scanner. This is designed for detecting a very large frequency range so that NG flames can be detected. The flame scanner is mounted and can be adjusted over an angle of 15deg. Make- Fireye Type- UV Scanner

7. BURNER SEQUENCE

8. Components of burner management system Fuel Control valve:- Regulates the flow of fuel to the furnace to ensure efficient and safe combustion. Flame Sensor:- Detects the presence of a flame in the furnace and sends the signal to the control system to shut off fuel if the flame is not detected. High Temperature alarm:- Monitors the temperature of the furnace and sounds an alarm if it exceeds a set limit. Pressure Sensors:- Monitors the fuel and air pressure in the furnace. Control panel:- The central component of the BMS that houses the control system and associated sensors, actuators and alarms. Software:- The control system software is responsible for monitoring the various inputs from the sensors and making adjustments to the fuel flow rate as necessary to ensure safe and efficient combustion.

9. HRU-BURNER MANAGEMENT SYSTEM The BMS- PLC (Burner Management System- Programmable Logic Controller) control system, has the following system:- Permissive To start SFS(Supplementary firing system) interlock Automatic burner Stop/Start

10. HRU INTERLOCKS

11. HRU INTERLOCKS

12. PERMISSIVE TO START The first Introduction of GT gas turbine exhaust flue gas into HRU (i.e. Diverter damper opening to allow GT exhaust gas into HRU furnace) is not permitted unless certain safe conditions are established. Full HRU trip has to be reset. Speed of GT>3950 and <5163 rpm (2/3 voting signal from Mk-Vie). Level in Boiler drum(2/3 voting by 36 LSL 115,116,117)>20%. HP steam superheater(SH-II) exit temperature (2/3 voting by TSH 141,142,143) is <540 degC . SH-II exit steam pressure(2/3 voting by 36 PSH 141,142,143) <123kg/cm2g. Re- circulation pump flow differential pressure(2/3 voting by 36 PDSL 126,127,128) >0.2kg/cm2.

13. PERMISSIVE TO START 7) Instrument header pressure(2/3 voting by 36 PSL401,402,403) >4.5kg/cm2g. 8) Diverter Damper(2/3 voting by 36 ZSL 207,208,209) is full Close towards Bypass Stack. 9) Diverter Damper(2/3 voting by 36 ZSH 204,205,206) is full open towards HRU. 10) Guillotine damper is in full open(2/3 voting by ZSH 201,202,203) condition. 11) All flame scanners to indicate "No Flame". 12) Reset of local field panel to be done. 13) Burner to be selected in NG mode on local panel

14. SFS Interlock for burner start Permissive for NG burner Start. All common start permissive to be Ok. NG fuel header pressure(2/3 voting by 36 PSL 301,302,303)>80mmWc. NG fuel header pressure(2/3 voting by 36 PSH 301,302,303)<3.6 kg/cm2g. NG line common vent(36 XV 302) to be closed( by limit switch 36 ZSL 302). NG supply block valve(36 XV 300) to be in open condition( by limit switch 36 ZSH 300). NG pressure control valve 36 PIC 301 to be in full closed condition( by limit switch 36 ZSL 300).

15. AUTOMATIC BURNER STOP/START SWITCH This facility is an extension of the fuel flow control logic and is used to automatically start/stop burners based on the increase/decrease in load demand signal received from DCS. Burner Auto Start- the first burner would have to be lit from field . After the first burner is lit the successive burners will be lit in the sequence(2-3-1-4). Burner Auto Stop- A reverse shut off sequence is used for decreasing energy demand. The shut off is in sequence(1-4-3-2).

16. The low voltage ignition unit The Housing unit contains 2 ignition units for the ignition of 2 low voltage ignition voltage ignition burners. The Ignition unit is suitable for supply voltage of 115V Ac, 50 HZ. Each ignition unit can be controlled separately with 115V AC control voltage. Ignition Supply Input-115VAC Output-2900V

17. Working of ignitor Capacitor Charging:- The ignition controller charges a capacitor to a high voltage using power from AC/DC inputs. Triggering Discharge:- At set intervals (often ~2 sparks/sec), a thyristor-based switch rapidly discharges the capacitor through the spark plug’s integrated electrodes. Spark Formation:- The discharge ionizes the spark gap and insulating surface using spark plug , creating a flame-shaped spark with current lasting a few micro- to milliseconds. This robust spark reliably ignites gas even in harsh conditions.

18. PILOT FLAME DETECTOR Pilot Flame Detection is done using DURAG AAL76 as it is ionization flame monitor used in industrial combustion system to ensure safe burner operation. Mounting- Standard DIN rail mounting Power- 115 VAC or 230 VAC as required Principle of Operation- Flame Ionization Feature- Self Monitoring during startup.

19. Working Principle Heat in the flame causes the collision into molecules around the flame. The force of the Valence electron frees some outer electrons forming the molecules. This creates free electrons and positive ions allowing the current conducted through the flame. The whole process is called Flame Ionization. Within the flame there is very low conductivity, and resistance can vary from 100000 to 100000000 ohms. Current conducted through the flame is generally in the range of 2-4 micro amps. The amount of current indicates the intensity of the flame. If two electrodes were places in a flame as shown in right with a voltage applied , a current could be conducted between two flame rods.

20. MAIN BURNER FLAME SCANNER Model- Fireye 85UV5 About- The Fireye Phoenix Series 2 type 85UV flame scanners is microprocessor-based device utilizing a solid-state flame detection sensor. Spectrum Response- 295-340 nm. Power- 24VDC Output- 4-20mA Feature- Integrated Flame and Fault relay Flame scanner

21. Working principle A UV scanner detector consists of UV sensors that is joined in a single apparatus. UV sensors work by detection of UV radiation emitted by the flame and are sensitive to a wide range of flammable fuels including hydrocarbons, sulfur and ammonia. A photodiode type UV sensor measures illuminance. When light strikes the photodiode, it energizes the electrons, which causes an electric current. The electric current will be stronger in response to brighter light. The electric current can then be measured and transformed into a analog output.

22. WORKING FLOW DIAGRAMs IGNITOR PILOT FLAME DETECTOR FLAME SCANNER

23. Architecture of plc I/O CARD PSU CPU PREFAB CABLE ESB

24. ADVANTAGE OF PROSAFE RS OVER OMRON PLC OMRON PLC PROSAFE RS PLC REDUNDANCY DUAL MODE REDUNDANCY VERSATILE MODE REDUNDANCY WIRING COMPLEX WIRING SIMPLE WIRING SUPPORT NO VENDOR SUPPORT VENDOR SUPPORT AVAILABLE SPARES OBSOLETE SPARES AVAILABLE

25. UPGRADATION IN THIS SHUTDOWN PLC – A new PLC has been installed of Yokogawa Prosafe RS model replacing the old PLC. The Barriers are of P&F make and their model is HiC2025(signal barrier) & HiC2081(temperature barrier). The difference between normal barriers and HiC barriers are as follows:- NORMAL BARRIER HiC2025 HiC2081 MOUNTING RAIL MOUNTED DIN RAIL MOUNTED, PLUG IN MODULES DIN RAIL MOUNTED, PLUG IN MODULES MAINTAINENCE MANUAL EASIER, DIAGNOSTIC LEDs EASIER, DIAGNOSTIC LEDs USES BASIC PROTECTION CIRCUIT PLC/DCS INTERFACE IN HAZARDOUS AREA PLC/DCS INTERFACE IN HAZARDOUS AREA

26. UPGRADATION IN THIS SHUTDOWN CPU UPGRADATION:- The "CPU S2SC70D" refers to a Yokogawa Safety Control Unit (SCS) model S2SC70D, specifically designed for safety instrumented systems.  The "D" in S2SC70D indicates a dual-redundant configuration for enhanced reliability.   The Key features are as follows- SIS (SAFETY INSTRUMENTED SYSTEM) DUAL REDUCDANT RACK MOUNTING COMMUNICATION

27. THANKYOU