Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
4.1.15Layout of facilities and equipment shall allow removal of generator transformers, station transformers and unit auxiliary transformers without disturbing structure, equipment, piping, cabling, bus ducts etc. routed in the area.
4.1.16Clear approach width of minimum 10m with clear height of 8m shall be provided at the front and rear of ESP.
4.1.17Trestles to be provided for routing of cables, pipes etc. shall have a clear height of 8.0m in main plant area, at road/ rail crossings so as to clear the road spaces/ railway lines, approach to maintenance bays of various buildings. A walkway with hand rails and toe guards of 600mm (minimum) width shall be provided all along length of the trestle for maintenance of cables and pipes. Ladders for approach to these walkways shall be provided near roads, passage ways at suitable locations.
4.1.18Floor drains shall be provided at all floors and drain discharge pipes shall be properly sized taking into account the fire water sprinkler system wherever provided.
4.1.19Valves shall be located in accessible positions. All piping shall be routed at a clear height of minimum 2.2 m from the nearest access level for clear man movement. Best engineering practices shall be adopted for keeping the minimum clear working space around equipment and clear headroom within main structures and cable trays etc.
4.1.20Fire water pipes in main plant area may be routed in trenches filled with sand and covered with pre-cast RCC covers.
4.1.21The safety requirements as per the Factories Act, Rules/ Regulations made under Indian Electricity Act 2003 and other applicable codes/standards etc. shall be observed while developing the layout.
4.1.22While developing the layout, all fresh air ventilation louvers shall be considered 1000 mm from floor level and directed downwards at an angle. Ventilation fans on AB bay roof shall be staggered and shall not be near the centre line of turbinegenerator set. Air washer units could be located at outside TG bay on' A' row side and in BC bay on 'B' row side.
4.1.23As per requirement of MOE&F, the space provision shall be kept for installation of flue gas desulphurisation (FGD) system in future, if required.
4.1.24Layout of the buildings shall be developed considering TAC requirements for fire escape. Adequate fire escape staircases shall be provided in main plant building with fire doors at each landing. Each equipment room shall be provided with alternate exits in case of fire/ accidents as per requirements of Factory Act and statuary bodies / Insurance companies.
4.1.25Each unit shall be provided with one passenger elevator in TG hall and one passenger cum goods elevator in the boiler area.
11
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
CHAPTER 5
PERFORMANCE GUARANTEES
5.1General Requirements
5.1.1The equipment shall meet the ratings and performance requirements stipulated for various equipment. The guaranteed performance parameters shall be without any tolerance values and all margins required for instrument inaccuracies and other uncertainties shall be deemed to have been included in the guaranteed figures.
5.1.2All the guarantees shall be demonstrated during functional guarantee/ acceptance test. The various tests which are to be carried out during performance guarantee/acceptance test are listed in this chapter. The guarantee tests shall be conducted at site on each unit individually.
5.1.3All instruments required for performance testing shall be of the type and accuracy required by the code(s) and prior to the test these shall be calibrated in an independent test Institute. The protecting tubes, pressure connections and other test connections required for conducting guarantee test shall conform to the relevant codes.
5.1.4Detailed Performance Test Procedure to be furnished shall contain the following:
i)Object of the test.
ii)Various guaranteed parameters & tests as per contract.
iii)Method of conductance of test and test code.
iv)Duration of test, frequency of readings & number of test runs.
v)Method of performance calculation.
vi)Correction curves.
vii)Instrument list consisting of range, accuracy, least count, and location of instruments.
viii)Scheme showing measurement points.
ix)Sample calculation.
x)Acceptance criteria.
xi)Any other information required for conducting the test.
5.1.5In case during performance guarantee test(s) it is found that the equipment/system has failed to meet the guarantees, all necessary modifications and/or replacements shall be carried out to make the equipment/system comply with the guaranteed requirements & the same shall be demonstrated by conducting another performance guarantee test at no extra cost to the purchaser. However, if the contractor is not able to demonstrate the
12
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
guarantees, even after the above modifications/ replacements within ninety (90) days or a reasonable period allowed by the purchaser, after the tests have been completed, the purchaser will have the right to either of the following:
i)For Category-I Guarantees
Reject the equipment/ system/ plant and recover the payment already made
OR
Accept the equipment/ system/ plant after levying Liquidated Damages as stipulated. (Amount of LD to be specified by the purchaser based on unit size, coal cost etc.)
ii)For Category-II Guarantees
Reject the equipment/ system/ plant and recover the payment already made. Conformance to the performance requirements under Category-II is mandatory.
iii)For Category-III Guarantees
Reject the equipment/ system/ plant and recover the payment already made.
OR
Accept the equipment/ system after assessing the deficiency in respect of the various ratings, performance parameters and capabilities and recover amount equivalent to the damages.
5.2Guarantees Under Category-I
The performance guarantees which attract liquidated damages are as follows:
5.2.1Efficiency of the steam generator at 100% TMCR with zero make up while firing the design coal at rated steam parameters, rated coal fineness and rated excess air.
5.2.2Efficiency of the steam generator at 80% TMCR with zero make up while firing the design coal at rated steam parameters, rated coal fineness and rated excess air (for reference).
5.2.3Steam generating capacity in T/hr. of steam at rated steam parameters at superheater outlet and rated steam temperature at reheater outlet (with any combination of mills working as per purchaser’s discretion) with the coal being fired from within the range specified.
5.2.4Turbine Cycle Heat Rate in kcal/kWh under rated steam conditions, design condenser pressure with zero make up at 100% TMCR load.
13
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
5.2.5Turbine Cycle Heat rate in kcal/kWh under rated steam conditions, design condenser pressure with zero make up at 80% TMCR load (for reference).
5.2.6Continuous TG output at 105% TMCR load under rated steam conditions, design condenser pressure with zero make-up.
Note: The condenser pressure measurement while conducting the guarantee tests from clause 5.2.4 to 5.2.6 above shall be measured at 300 mm above the top row of condenser tubes.
5.2.71Pressure drop across terminal points of condenser cooling system with on-line condenser tube cleaning system in operation.
5.2.8The total auxiliary power consumption for all the auxiliaries of boiler, turbine Generator and turbine cycle equipments required for continuous unit operation at 100% TMCR load under rated steam conditions and at design condenser pressure with zero make-up.
5.2.9The total auxiliary power consumption for all the auxiliaries of boiler, turbine Generator and turbine cycle equipments required for continuous unit operation at 80% TMCR load under rated steam conditions and at design condenser pressure with zero make-up (for reference).
5.3Guarantees Under Category-II
5.3.1It shall be guaranteed that, with one field out of service in each stream, the
particulate emission from ESP at TMCR load and design coal firing shall not exceed 50 mg/Nm3 or stipulated requirement of MOEF’s in this regard, whichever is more stringent. The corresponding ESP efficiency shall be worked out.
5.3.2It shall be guaranteed that maximum total NOx emission from the unit will not be more than 260 grams of NOx (from thermal as well as fuel) per giga joule of heat input to the boiler at 6% O2 level during the entire operating range of steam generator for the range of coals specified or as per MOEF’s requirement in this regard (if applicable) whichever is more stringent.
5.4Guarantees Under Category-III
The parameters/ capabilities to be demonstrated for various systems/ equipments shall include but not be limited to the following:
5.4.1Run back capabilities
The automatic runback capability of the unit (boiler- turbine-generator) on loss of critical auxiliary equipment (such as tripping of one ID /FD /PA fan/ BFP etc.) shall be demonstrated ensuring smooth and stable runback operation.
1 Applicable in case CW pumps are not included in scope of BTG system. 14
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
5.4.2Start up time (for one unit only)
Start-up time (upto full load), and loading capabilities for the complete unit (boiler, turbine and generator together) for cold start, warm start and hot start conditions as agreed shall be demonstrated, ensuring that the various turbine operational parameters like vibration, absolute and differential expansion, eccentricity and steam metal temperature mismatch etc. are within design limits.
5.4.3Rate of change of load and sudden load change withstand capability
The capability of boiler-turbine-generator in regard to ramp rate and step load change as specified shall be demonstrated.
5.4.4Mill capacity at rated fineness
Performance testing shall be done on coal mills towards establishing the specified capacity at the rated fineness, applying corrections for the variation in coal characteristics i.e., HGI (Hardgrove Grindability Index) and total moisture. The test shall be demonstrated on 50% of the installed coal pulverizers (of Purchaser's choice) of each Steam Generator at 100% mill loading with the originally installed grinding elements in nearly worn-out condition or at the end of guaranteed wear life of grinding elements, whichever is earlier. Capacity test shall be demonstrated at the following conditions occurring simultaneously during testing:
i) Coal fineness |
Not less than 70% through 200 mesh and not less than |
|
98% through 50 mesh screen. |
|
|
ii) Test coal |
Any available coal from the specified range with coal |
|
sampling done as per ISO 9931. |
|
|
In case the guaranteed capacity of coal pulverizers as stated above are successfully demonstrated, remaining coal pulverizers of corresponding steam generator will also be considered to have successfully met the above capacity guarantee requirement. However, in the event of any of the coal pulverizers not meeting the guarantee test, all the coal pulverizers of corresponding steam generator will have to be tested to demonstrate guaranteed capacity.
5.4.5Life of mill wear parts
Life of mill wear parts, in hours of operation, for the entire range of coal characteristics specified shall be demonstrated.
15
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
5.4.6Electrostatic precipitator
i)The ESP air in leakage shall not be more than 1% of total gas flow at ESP inlet at the guarantee point condition and shall be demonstrated.
ii)The maximum pressure drop through the ESP at the guarantee point flow condition shall not exceed 25 mmwc and shall be demonstrated.
iii)Uniformity of the gas distribution in the various streams and inside the casing shall be demonstrated as per specified/ quoted value.
5.4.7No fuel oil support above 40% BMCR load
It shall be demonstrated that oil support for flame stabilization shall not be required beyond 40% of BMCR load when firing the coals from the range identified. It shall also be demonstrated that with any combination of mills/ adjacent mills in service, the steam generator shall not require any oil firing for stable and efficient boiler operation at and above 40% BMCR load.
5.4.8Performance characteristics of fans
Satisfactory operation of FD, ID and PA fans without undue noise and vibration while operating in isolation or in parallel with other fans shall be demonstrated at site.
5.4.9Steam temperature imbalance
It shall be demonstrated at SH and RH outlets (in case of more than one outlet) that the temperature imbalance between the outlets does not exceed 100 C under all load conditions.
5.4.10SH and RH tube metal temperature
It shall be demonstrated that superheater and reheater tube metal temperature at critical locations remain within maximum tube metal temperature limits as per design of the OEM under various load conditions (i.e. 100%, 80%, 60% & 50%).
5.4.11Superheater and reheater attemperation system
It shall be demonstrate that the spray water flow of SH attemperation system does not exceed 8% of main steam flow, at superheater outlet, while firing any coal from within the range specified with HP heaters in service while maintaining the rated SH outlet steam temperature at all loads upto and including BMCR. It shall also be demonstrate that the RH temperature is maintained at the rated value without any spray water requirement under normal operating conditions.
16
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
5.4.12Furnace exit gas temperature (FEGT)
It shall be demonstrated that maximum furnace exit gas temperature (FEGT) shall be minimum 60 deg C below the minimum initial deformation temperature (IDT) of ash. A comprehensive thermal performance test (TPT) shall be conducted for this purpose on one unit. FEGT shall be demonstrated through such TPT by indirect measurement.
5.4.13Air heater air in leakage
It shall be demonstrated that the air-heater air-in-leakage after 3000 hours of steam generator operation does not exceed the specified/ quoted values.
5.4.14Equipment cooling water system
i)Inlet and outlet temperatures on the primary and secondary side of the plate type heat exchangers as per design shall be demonstrated at site.
ii)Pressure drop across plate type heat exchanger on primary and secondary side cooling water circuits shall be demonstrated at site.
iii)Satisfactory operation of primary side DMCCW pumps and secondary side cooling water pumps (as applicable) without undue noise and vibration while operating in isolation or in parallel with other pumps shall be demonstrated at site.
5.4.15Generator excitation system
The performance of generator excitation system as specified shall be demonstrated.
5.4.16Steam condensing plant
i)The value of design condenser pressure, to be measured at 300 mm above the top row of condenser tubes, shall be demonstrated under VWO condition, 1% make-up, design CW inlet temp. and CW flow. The condenser vacuum shall be measured with a vacuum grid utilizing ASME basket tips.
ii)Temperature of condensate, at outlet of condenser, shall be demonstrated to be near to saturation temperature corresponding to the condenser pressure at all loads.
iii)Oxygen content in condensate at hotwell outlet shall not exceed 0.015 cc/litre over 50-100% load range and shall be determined according to calorimetric Indigo-Carmine method.
iv)Air leakage in the condenser under full load condition shall not exceed more than 50% of design value taken for sizing the condenser air evacuation system.
17
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
v)When one half of the condenser is isolated, condenser shall be capable of taking at least 60% T.G. load under TMCR conditions.
vi)The design capacity of each vacuum pump in free dry air under standard
conditions at a condenser pressure of 25.4 mm Hg (abs) and sub cooled to 4.170C below the temperature corresponding to absolute suction pressure shall be demonstrated. Correction curves for establishing the capacity at site conditions shall also be furnished.
vii)The air and vapour mixture from air cooling zone of condenser shall be 4.170C below the saturation temperature corresponding to 25.4 mm Hg (abs) suction pressure. Correction curves for establishing the same at site conditions shall also be furnished.
viii)2Pressure drop across terminal points of condenser cooling system with on line condenser tube cleaning system in operation.
5.4.17Feed water heaters and deaerator
The following parameters shall be demonstrated:
i)TTDs and DCAs of feed water heaters shall be demonstrated as per guaranteed heat balance diagram for 100% TMCR condition.
ii)Outlet temperature from final feed water heater(s).
iii)Difference between saturation temperature of steam entering the deaerator and temperature of feed water leaving the deaerator shall be demonstrated as per guaranteed heat balance diagram for 100% TMCR condition.
iv)Continuous and efficient operation and performance of feed heating plant without undue noise and vibrations at all loads and duty conditions.
5.4.18HP & LP bypass system capabilities
The design capacity of HP/ LP bypass system shall be demonstrated. Further, the HP & LP bypass system should satisfy the following functional requirements under automatic interlock action. It should come into operation automatically under the following conditions:
i)Generator circuit breaker opening.
ii)HP & IP stop valves closing due to turbine tripping.
iii)Sudden reduction in demand of external load (load throw off).
2 Applicable in case CW pumps are included in scope of BTG system. 18
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
Under all above conditions, while passing the required steam flows as per the relevant heat balances, the condenser should be able to swallow the entire steam without increasing the exhaust hood temperature and condenser pressure beyond the maximum permissible values. The same shall be demonstrated.
5.4.19Power cycle pumps
Satisfactory operation of BFPs and CEPs without undue noise and vibration while operating in isolation or in parallel with other pumps shall be demonstrated at site.
5.4.20Condenser on load tube cleaning system
Life of sponge rubber balls and number of balls lost during 1000 hours of plant operation as agreed in contract shall be demonstrated.
5.4.21Automatic on-line turbine testing (ATT) system
On-load testing of turbine protective equipments without disturbing normal operation and keeping all protective functions operative during the test shall be demonstrated.
5.4.22Noise
i)All the plant, equipment and systems shall perform continuously without exceeding the specified noise level over the entire range of output and operating frequency.
ii)Noise level measurement shall be carried out using applicable and internationally acceptable standards. The measurement shall be carried out with a calibrated integrating sound level meter meeting the requirement of IEC 651 or BS 5969 or IS 9779.
iii)Surface sound pressure shall be measured all around the equipment at a distance of 1.0 m horizontally from the nearest surface of any equipment/ machine and at a height of 1.5 m above the floor level in elevation. The average of A-weighted surface sound pressure level measurements expressed in decibels to a reference of 0.0002 micro bar shall not exceed 85 dBA except for:
a)Safety valves and associated vent pipes for which it shall not exceed 115 dBA with silencer as applicable.
b)Regulating drain valves in which case it shall be limited to 90 dBA.
c)TG unit in which case it shall not exceed 90 dBA.
d)HP and LP bypass valves operation for which it shall be restricted to 115 dBA.
19
Standard Technical Features of BTG System for Supercritical 660/800 MW Thermal Units
e)For air motors it shall not exceed 95 dBA.
f)For pressure regulation valves & steam generator water drain control valve it shall not exceed 90 dBA.
Corrections for background noise shall be considered in line with the applicable standards.
5.4.23Condensate polishing plant
i)Effluent quality at outlet of each vessel at its rated design flow and design service length between two regenerations.
ii)Pressure drop across the polisher service vessel, as specified, in clean and dirty condition of resin at rated design flow.
5.4.24Control & Instrumentation system requirements
Performance guarantee tests for closed loop control systems shall be carried out at site to verify the integrated performance of the C&I system and to verify as to whether all the important parameters remain within stipulated permissible limits under all the operating conditions. In case during these tests or otherwise it is observed that the behavior/ response of individual system (drives actuators/ valves etc.) is not satisfactory/ acts as a limitation/ restriction in achieving the permissible limits, all required modifications, rectification etc. shall be made in the C&I system so that the permissible limits can be achieved.
5.4.25EOT crane
After assembly and erection of crane at site, the crane shall be subjected to deflection test, overload test, brake test and other tests as per IS 3177.
5.4.26 Elevators
After installation at site, the elevators shall be subjected to the following tests:
i)Overload test.
ii)Travel speed and hoist speed checks.
iii)Drop test.
iv)Checks for interlocks & safety systems.
v)Checks for operation from inside the cage.
5.5Test Codes, Test Conditions etc.
5.5.1Steam generator efficiency
i)The steam generator efficiency shall be determined as per the requirements of ASME PTC- 4 (by energy balance method) and other stipulations brought out hereunder.
20