Petroleum Development Oman LLC
Contract Number C311606
EPC Contract for Yibal Khuff Cogeneration Power Plant
C6-01 – PROJECT INFORMATION & REQUIREMENTS
Table of Contents
3.0 Environmental and Meteorological Data. 3
3.4 Soil Thermal Resistivity, Seismic and Solar Radiation. 4
5.0 Air Conditioned Rooms (Redundant Systems) 5
7.1 AC System Voltages, Frequency and Neutral Earthing. 5
11.0 Surface Protection and Coating Systems. 7
13.0 Instrument Air Parameters. 8
14.0 Fuel Gas Specification. 8
1.0 Site Conditions
The Yibal Khuff Cogeneration Power Station will be located in Yibal field area, approximately 50 km south west of the Fahud field and 350 km south west of Muscat, in the PDO concession area.
2.0 Soil Investigation
Soil investigation report shall be provided by Company for information during tender submission.
3.0 Environmental and Meteorological Data
3.1 General
Local conditions are severe, the climate being characterised mainly by extreme heat and humidity.
3.2 Geographic Data
Location Yibal Khuff
Elevation above MSL: 80 – 100 m
3.3 Ambient Temperatures
The climate is mainly hot and humid. Summer runs from April to October with June and July being the hottest months. The following are the standard ambient conditions that shall be considered for Yibal Khuff.
Ambient Air and other Temperatures | |
Maximum shade temperature:
Minimum shade temperature: Maximum black bulb temperature: Maximum daily variation in temperature:
|
60ºC
5ºC 82ºC 25°C
|
Maximum ground temperature at various below-grade-levels:
Minimum ground temperature: |
30°C @ 1000 mm
35°C @ 800 mm 38°C @ 650 mm 40°C @ 500 mm
22°C @ 1000 mm |
Humidity | |
Maximum Relative Humidity:
Minimum Relative Humidity: |
98%
15% |
Barometric Pressure | |
Barometric Pressure range: | 98.8 to 100.5 kPa |
The minimum and maximum values have been extrapolated using Yibal elevation of 90 m above MSL from OceanMetrix report. | |
Rainfall | |
Maximum infrequent heavy rainfall:
|
38.1mm / hour (Considering 50 year return period from Ocean Metrix Data) |
3.4 Soil Thermal Resistivity, Seismic and Solar Radiation
Soil thermal resistivity value to be used for arriving at de-rating factors for cable capacity calculations: | 240oC cm/W |
Seismic activity
The seismic coefficient to be applied is Zone 2A of Uniform Building Code, UBC 97 |
Low
|
Maximum Iso-keraunic level | 10 days per annum |
Solar radiation: | 1200 W/m2. |
3.5 Sandstorms
Sandstorms are both frequent and severe and can continue for days with the atmosphere heavily laden with dust particles. Fine dust in these sandstorms can be as small as 2 microns.
3.6 Wind
The wind rose shall be based on the OceanMetrix report as shown below:
Design Wind Speeds:
Design wind speed (twice/month) 46.6 m/s (3 sec gust for 50 years return period as per Ocean Metric data)
For Process design, wind speed of 23.8m/s shall be used.
4.0 Design Conditions
Design temperature for transformers shall be 55°C as per SP – 1117 and ratings for other electrical equipment shall be as per site conditions spelt out in SP – 1103.
The output of the gas turbine generator shall not be limited by the generator, or interconnecting cable or generator transformer over a temperature range 5ºC to 55ºC.
All instrumentation shall be designed to function correctly with an ambient temperature of 60ºC if shaded or 82ºC if not shaded.
In general, the design temperature conditions for all the instrument equipment shall be as described below:
- All instruments, systems and related components in hazardous areas shall comply as a minimum with the environmental conditions associated with hazardous area rating Zone-1, Gas Group IIA/B, Temperature Class T4.
- Plant-mounted instruments shall be suitable for operation in industrial, humid, saliferrous and corrosive atmospheres and shall be adequately protected according to the electrical area classification.
- For outdoor locations the climatic conditions of location class Dx(4k6/4Z2/4Z4/4Z6/4C2/4S4/4M1) of IEC 60654-1 (IEC 60721-3-4 incl. Amendment 1) applies.
- The minimum degree of protection of plant instruments shall be IP 65 as defined in IEC 60529.
- For mechanical influences, classification in accordance with IEC 60654-3 shall apply. For corrosive influences, classification in accordance with IEC 60654-4 shall apply. The corrosive influence class shall comply with the requirements of Tropicalisation (conformal coating) of printed circuit boards is required for all equipment in outdoor areas.
- Installation and inspection of Ex equipment/instruments shall be carried in accordance to PR 1483 and IEC 60079 (Part 14 and 17) under the supervision of Ex inspector approved by Company.
- The glands, seals etc. required for the completion of installation of all Ex equipment/ instruments shall be Ex rated.
For the design of air coolers the summer design temperature shall be 50ºC with a 10ºC approach. The winter design temperature shall be 20ºC with a 10ºC approach; however the equipment must be able to function at a shade temperature of 5ºC.
The maximum shade temperature occurs for short periods only. Equipment shall be designed to achieve its rated capacity with a shade temperature of 50°C except for compressor auxiliaries, which shall be rated for 60°C.
The outdoor electrical equipment, instruments (switchgear, transformer, motor, transmitters etc.) shall be designed for 55°C ambient temperature. The indoor equipment shall be designed for 40°C ambient temperature.
5.0 Air Conditioned Rooms (Redundant Systems)
Inside design temperature is:
- Maximum 21 ± 2°C with all units operating,
- 35 ± 2°C °C with one unit out of service.
Equipment installed in such rooms shall be specified for a continuous operating temperature of 40°C, and for two hours in a day, at 55°C.
6.0 Heat Exchangers
For the design of air coolers the summer design temperature shall be 50ºC with a 10ºC approach. The winter design temperature shall be 20ºC with a 10ºC approach; however the equipment must be able to function at a shade temperature of 5ºC.
7.0 Electrical Systems
Details of the electrical systems are as follows: –
7.1 AC System Voltages, Frequency and Neutral Earthing
Frequency: 50Hz
High voltage 132kV, 3 phase, solidly earthed
33 kV, 3 phase, – Neutral earthing through resistance
11 kV, 3 phase, resistance earthed
(See SP- 1103)
Medium Voltage 6.6kV, 3 phase, resistance earthed
(See SP-1103)
Low voltage 415/240V, 3 phase & neutral solidly earthed
7.2 AC Supply Variations
Steady state Voltage 132kV: + 10% at consumer terminals
Steady state Voltage below 132kV + 5% at consumer terminals
Steady state Frequency: + 2% at consumer terminals
Dynamic Voltage: + 15% at common buses
7.3 DC Supply Variations
The output voltage shall be limited to within ± 10% of the nominal value. This limitation applies during, float-charge operations and during battery discharge operations corresponding to the maximum load current and for the specified discharge period. The output voltage dynamic response of the DC UPS unit, with battery connected, shall not vary more than +20% or -10% of nominal output voltage in the event of instantaneous load changes of up to 50% rated output.
7.4 Fault Levels
132kV System | Short Time Current – 31.5kA for 3 seconds |
Short Circuit Withstand Current – Company will advise the rms value, including the direct-current (dc) component, at the major peak of the maximum cycle as determined from the envelope of the current wave form over a given time period. (The Short Circuit Withstand Current shall be used in electromechanical force calculations) | |
Rated Short time current rating of OPGW -25kA, 1sec as per SP-1114B Appendix-01 | |
Medium Voltage System | Switchgear shall have minimum short time fault rating based on the actual calculated Fault Level plus 10% with the minimum being 25kA for 1 sec. |
Cable screen shall have min. fault level 3kA for 1sec | |
Low Voltage System
|
10% margin above actual calculated Fault Level |
Earthing system shall be designed for Switchgear fault rating e.g. for 132kV earth grid, 31.5kA 6.6kV earth grid 25kA if applicable.
7.5 DC Systems
Nominal service voltages 110V 2 pole unearthed
125V 2 pole unearthed
24V 2 pole unearthed
48V 2 pole – positive earthed
7.6 Equipment Ratings
Equipment will be suitable for operation at the following voltages:
Motors 185kW‑2200kW 6.6kV
Motors up to 160kW 415V
Lighting supply 415/240V; 3 phase & neutral
Lighting systems 240V; phase & neutral
Instruments (non-vital) 240V; phase & neutral
Instruments (vital) 240V; phase & neutral
Instruments (vital) 24V DC floating
Instruments (non-vital) 110V DC floating
Instruments (vital) 110V DC floating
Welding outlets 415V; 3 phase & neutral
Convenience outlets 240V; phase & neutral
Switchgear closing 110V DC floating
Switchgear tripping 110V DC floating
Electrical SCADA system 48V DC positive earth
The requirements of system for HV (132/6.6/11kV) and LV (415 V) systems shall be as stated in SP–1113 and SP–1103 except for the following equipment operating voltages
- Welding & Oil filtration sockets : 415 V 3Ph, N
- Switch Gear Spring charging : 110 V DC
- SCADA Interposing relay : 48 V DC
- Transducers : 110 V DC
- 6kV System : Resistance earthed as per
SP 1103
8.0 Environmental Impact
Transformers contain oil, which will be contained in a catchment bund in case of leakage. The 132kV circuit breakers use SF6 gas as a current breaking medium. GIS switchgear also contains SF6 gas as an insulating and current breaking medium. SF6 gas is non-toxic in normal situations, however after a fault clearance the byproducts of SF6 gas decomposition are very toxic and special precautions must be taken when servicing the interruption chambers of these circuit breakers. Safety procedures set out in Company SPs will be followed when handling SF6 gas and in the event of gas leakage.
9.0 NOISE EMMISSIONS
The noise level of all equipment shall not exceed the limits as specified in DEP 31.10.00.31-Gen. The maximum permissible noise level (sound pressure level) at a distance of 1 m and 1.5 m above reference level from the complete pump package shall be 85 dB (A). EPC contractor shall submit the guaranteed sound power levels and sound pressure levels of the equipment. The equipment shall meet the maximum noise limits by design and not by corrective measures.
10.0 Availability
Supplies to each switchboard will be designed to provide N-1 redundancy.
11.0 Surface Protection and Coating Systems
Specification SP-1246 covers the minimum requirements for protective painting and coating systems, materials and application methods for the internal and external surface of steel structures and equipment.
12.0 Water quality
12.1 Utility Water -Potable/ Polished condensate composition will be confirmed during detailed design. Information provided below is preliminary.
Description | Unit | |
pH | 7 | |
TDS | mg/l | 997 |
Ca | mg/l | 90 |
Mg | mg/l | 42 |
Na | mg/l | 163.4 |
K | mg/l | 5.5 |
Ba | mg/l | 0.05 |
Sr | mg/l | 8.3 |
Fe | mg/l | 0.01 |
Cu | mg/l | 0.04 |
CO3 | mg/l | 0.1 |
HCO3 | mg/l | 184.3 |
SO4 | mg/l | 213.6 |
Cl | mg/l | 279 |
F | mg/l | 0.9 |
NO3 | mg/l | 0 |
B | mg/l | 0.05 |
SiO2 | mg/l | 10 |
CO2 | mg/l | 29.17 |
O2 | mg/l | 1.5-5 |
Cl2 | mg/l | – |
Turbidity | mg/l | – |
12.2 Boiler Feed Water
Boiler feedwater will be supplied by the Central Processing Facility. The supply condition at battery limit is at 30 barg and 140 deg C. HRSG and auxiliary boilers. Feedwater parameters shall meet BS EN 12952-12:2003 guideline.
13.0 Instrument Air Parameters
The typical Instrument Air parameters will be as following:
Pressure: 550 kPa (g) Minimum, 1,000 kPa (g) Maximum
Temperature: 50 °C Maximum
14.0 Fuel Gas Specification
The fuel gas composition is given below. Facility design shall be based on the following cases.
- YK-0°C cricondentherm gas
- YK-17°C cricondentherm gas: Design case for GTP and GT
- GGS-7°C cricondentherm gas
Case 1 | Case 2 | Case 3 | |
Component | YK – 0°C Cricondentherm | YK – 17°C Cricondentherm | GGS – 7°C Cricondentherm |
Nitrogen | 0.0783499 | 0.0780200 | 0.0463 |
CO2 | 0.0000008 | 0.0000008 | 0.0050 |
H2S | 0.0000007 | 0.0000007 | 0.0000 |
Methane | 0.8326226 | 0.8291984 | 0.8668 |
Ethane | 0.0470996 | 0.0469266 | 0.0468 |
Propane | 0.0234892 | 0.0234657 | 0.0204 |
i-Butane | 0.0047099 | 0.0048525 | 0.0042 |
n-Butane | 0.0080707 | 0.0085556 | 0.0054 |
i-Pentane | 0.0021622 | 0.0026765 | 0.0018 |
n-Pentane | 0.0023011 | 0.0031113 | 0.0015 |
n-Hexane | 0.0009485 | 0.0022262 | 0.0014 |
Mcyclopentane | 0.0000486 | 0.0001180 | 0.0000 |
Cyclohexane | 0.0000462 | 0.0001271 | 0.0000 |
n-Heptane | 0.0000679 | 0.0003303 | 0.0005
|
Mcyclohexane | 0.0000168 | 0.0000744 | 0.0000 |
n-Octane | 0.0000063 | 0.0000570 | 0.0001
|
n-Nonane | 0.0000004 | 0.0000045 | 0.0000 |
FC7* | 0.0000469 | 0.0001840 | 0.0000 |
FC8* | 0.0000090 | 0.0000614 | 0.0000 |
FC9* | 0.0000006 | 0.0000065 | 0.0000 |
M-Mercaptan | 0.0000004 | 0.0000004 | 0.0000 |
E-Mercaptan | 0.0000004 | 0.0000005 | 0.0000 |
2Propanthiol | 0.0000001 | 0.0000002 | 0.0000
|
H2O | 0.0000010 | 0.0000013 | 0.0002
|