STEAM TURBINE-GENERATOR & AUXILLIARY SYSTEMS Presentation by: RANA NASIR ALI General Manager, Power Plants Projects, at PITCO November 02, 2017

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1 STEAM TURBINE-GENERATOR & AUXILLIARY SYSTEMS Presentation by: RANA NASIR ALI General Manager, Power Plants Projects, at PITCO November 02, 2017

2 CO-GENERTATION POWER PLANT CONCEPT For dimensioning, design and layout of the various plant components and installations, the following features and aspects will be considered: Ratings to safely cope with load demand conditions, the prevailing site conditions, avoiding any over-stressing of material and equipment. Equipment to be of standard design, providing highest degree of safety, reliability, availability, redundancy and ease in operation Equipment arrangements to consider adequate space and access for transportation, storage, installation, operation and maintenance. The layout, design and manufacturing of all mechanical equipment shall comply with the latest edition of the relevant international standards

3 COGENERATION POWER PLANT - ECONOMICAL CONFIGURATION Advantage Disadvantage It is a simple Having low investment Condensing wheel has low efficiency during season The steam turbine will have low efficiency as it will run at 60 to70% of the steam load during off season. When one main equipment trip then sugar mill will shut down

4 COGENERATION POWER PLANT RELIABLE CONFIGURATION Advantage High redundancy in case same quality will be taken for equipment as of option. a When one unit trips then other unit can run at 50% load Disadvantage Condensing wheel has low efficiency during season High investment costs of approx. 24% of total investment cost because of additional boiler and steam turbine.

5 COGENERATION POWER PLANT OPTIMAL CONFIGURATION Advantage In case back pressure trips then condensing/extraction steam turbine can run and plant has an output of 70% load High efficiency during season and off season Disadvantage 2nd steam turbine which result in higher investment cost High storage of bagasse The size of boiler and steam turbine can be 12 to 14% smaller

6 STEAM TURBINE CONCEPT There are 2 types of turbines: The impulse type is used in higher pressure zones in order to minimize the leakage around wheels The reaction turbine is used in lower pressure zones as above the condensers.

7 Steam Extractions From Condensing Turbine

8 Design Basis of Steam Turbine Typical 26.5 MW cogeneration plant may be designed with one (1) no. 135 TPH boiler, one (1) no MW Nominal capacity Extraction Cum Condensing Turbo-generator with One (1) Deaerator, two (2) High Pressure Feed water heaters and auxiliary systems. Part of the generated power will be fed to the sugar plant, cogeneration plant auxiliaries and the balance of the generated power may be exported to the National Grid. Generation voltage will be 11 kv however the voltage may be stepped up to 132 kv or 220 kv for paralleling with Grid. Steam extracted from turbine provides the source to fulfill part of the process steam requirements for sugar plant, de-aerator and feed water heating. Balance of steam expands through LP stages of turbine and is condensed in the Water Cooled condenser. The Governor and Excitation system shall be selected and tuned to take care of all necessary protections to meet the operating condition. Load set point shall remain unaffected for variation of frequency between 47.5 Hz and 52.5 Hz. Turbine inlet steam pressure shall be maintained at set value by controlling power export to grid.

9 Design Engineering Features Codes and Standards DESIGN ENGINEERING FEATURES Highest possible thermal and energy efficiency. State-of-the-art technology and well proven in actual operation over a long period. Rugged, conservatively designed, proven components and systems. Minimum outage for field maintenance and routine inspection. Better operability at various load conditions. Advanced control and protection system, reliable online supervisory and surveillance system with diagnostics. Minimum requirement of operating and maintenance man- power and suitable for automatic operation. Suitability for harsh tropical ambient conditions at site. Simple design for ease of installation and operation. All equipment, systems, hardware, and services covered shall comply with specific standards applicable for the major equipment and system in the turbine package. None of critical speeds shall fall within range of 30% above and 30% below the normal running speed of Various rotating equipment CODES AND STANDARDS Turbine: o IEC Recommendation Publication No: 45 o ASME PTC-6 o VDI o DIN 1943 Piping : o ASME B31.1 o ASME Section VIII o HEI Standard

10 Steam Turbine and Auxiliary Systems Extraction Cum Condensing multistage impulse reaction type steam turbine complete with casing, rotor, blading, bearings and glands. Base frame for turbine, gear box and alternator with necessary bearing pedestals, shims, sole plates, keys, wedges, foundation bolts, all embedment's and grouting materials, etc. Steam from high pressure zone of steam turbine is extracted as first extraction for HP Feed water Heater II. Second extraction will be an uncontrolled at 9 Bar(a) for meeting the requirements of the heating steam for the HP Feed water Heater I, Ejector and process steam requirement. Third extraction will be an Auto- Controlled at 3 Bar(a) for fulfilling process steam requirements of the sugar plant, as well as heating steam requirements of the De-aerator and LP Feed water Heaters. Spray water for pressure reducing station and de-super-heater for maintaining steam temp. to specified value. Quick Closing Non-Return Valves, and Relief Valves in all the extraction lines. High speed coupling between the turbine and the gear box, and low speed coupling between the gear box and the alternator with acoustic cover made of solid castings. Hydraulically operated stop and emergency valve, throttle valve and governing valves with steam strainers. Two shell & tube High pressure feed water heaters with all accessories. Microprocessor based Electro-Hydraulic governing system (Woodward 505 E, suggested) including speed changer. Gland sealing system consisting of steam pressure regulators, gland steam condenser, 2 x 100 % motor driven exhausters, piping, fittings, valves, exhaust hood spray water system, etc.

11 Steam Turbine and Auxiliary Systems Lube and control oil system with adequate redundancy, common for turbine gear box and generator. One oil reservoir complete with strainers, drains, openings, vents, connections to oil inlet, outlet and to oil purifier unit, oil level indicator, level switches and 2 x 100 % oil vapor extractors as well as one duplex oil purifier system. Two 100% oil coolers with necessary three way switching valves. Two 100 % oil filters individually for the lube and control oil with necessary two way change over valves. One A.C. motor driven main oil pump, one auxiliary oil pump and one emergency oil pump driven by D.C motor. Suitably sized gas filled oil accumulator to be provided in the control oil circuit. Emergency gravity lube oil system with overhead tank, piping, valves and instrumentation. A.C. motor driven barring gear system with manual engagement and automatic disengagement. 3 x 50 % capacity A.C. driven vertical canister type condensate extraction pumps with base plate and anchor bolts. Hot well with level control system, isolation valves, 2 x 100 % level control valves and 30 % level control valve. Steam extraction piping to HP heater I & II and LP extraction steam piping to terminal point from turbine nozzles. HP heater II drain piping with level control to HP heater I and HP heater I drain piping to Feed Water storage tank Spray water piping from terminal point to all PRDS including spray water pressure reducing stations. 11

12 Salient Features of Steam Turbine Over Loading The system offered shall be suitable for an occasional over load of 10% of the rated capacity. Economic Load operation The specific steam consumption shall be the lowest for operating loads between 80 to 100%. Minimum load operation The minimum load at which turbine is required to operate continuously shall be 15% of the designed capacity. No load operation The turbine shall be capable of operating under no load during loss of load for a max. period of 60 minutes. Parallel operation The turbine generator shall be capable to run in parallel with other turbine generator or National Power Grid. Maximum Speed Over speed shall not be more than 20% of rated speed. Duration of over speed test shall be less than 2 minutes. Over speed trip The turbine generator shall be protected by a separately actuated over speed device which operates trip system. Governing Characteristics The operation of electronic speed governor shall prevent speed rise to a value at which the over speed trip is set. Barring Gear Mechanical type, A.C. motor driven Barring Gear shall rotate turbine generator after shutdown from rest and run it at low speeds to prevent thermal distortion of rotor and suitable for manual turning in case of A.C supply failure. 12

13 Cogeneration The steam turbine and auxiliary systems equipment, depending on the power plant / unit size and type of steam turbine viz. condensing, non-condensing and steam extractions arrangement will mainly comprise the following: Steam Turbine condensing or non-condensing or both features Steam Extractions for Feed Water Heating System / Process System Steam Turbine Lube Oil, Jacking Oil and Control Oil System Steam Turbine Glands Sealing Steam System Steam Condenser with Hot well for condensate collection Condenser Vacuum System Feed Water De-aeration and Heating System Condenser and Auxiliary Cooling Water System ( OC / CC) Air Compressor system for Service and Instrument Air Ventilation system Fire Detection and Fire Protection Elevators and Turbine Hall Crane

14 Steam Turbine Generator Performance Guarantee PERFORMANCE GUARANTEE The following performance guarantees for the Turbo-generator & auxiliaries in line with specified Employer's requirements. The performance guarantee test shall be conducted as per PTC 6 with zero tolerance and exclusive of the instrument tolerances. Sr. No. I Season Operations Description Unit Value kw Power Output at Generator Terminals Power Consumption of Auxiliary Equipment Cooling Water Flow Max. Temperature rise in the Generator windings above maximum inlet temperature of cooling air 45 Degree C kw Cub. m/hr. Degree C Stator 85 Rotor 90 II Off Season Operations Power Output at Generator Terminals Power Consumption of Auxiliary Equipment Cooling Water Flow Max. Temperature rise in the Generator windings above maximum inlet temperature of cooling air of 45 Degree C kw kw Cub. m/hr. Degree C Stator 85 Rotor 90 Signature of the Tenderer:

15 Thank You for Your Kind Attention