1. General
1.1 Design input
12X3MW
1.2 Project brief
At the requirement of the Buyer, the Seller will build a 12x3MW HFO Power Plant for Buyer operating with HFO/HSD;
The power plant consists of 12 sets of diesel generators, with capacity of 3000KW per set;
Install capacity of 36MW.
1.3 DG set configuration
The specification outlines the scope of supply for each DG set;
The DG set is driven by diesel engine model DN8320ZD6 manufactured by ND, which is the largest middle speed engine manufacturer in China;
The engine will use heavy fuel oil (380cSt/50°C)as fuel.
1.4 Standard & code
The design is according to the Chinese standard & code, in line with ISO/IEC standard. The project designed under the merit of "advanced technology, highly efficiency, safety, economy and practicality.
The installation and the commissioning should be in line with the above standard & code.
1.5 Project scope
The scope of the Seller:
Engineering design of the power plant, including power system, fuel system, lubricating oil system, starting air system, cooling water system, air intake & exhaust, compressed air system, control & measuring system, electrical system, etc;
Supplying equipments and materials according to scope of delivery list
2. Design Fundamentals
2.1 Civil work:
The civil works of the power station and fuel storage are NOT included in Supply Scope. The Seller will provide the following drawings and technical information, which will assist civil consultant in designing the foundation and powerhouse.
- General assembly drawing
- Powerhouse layout
- Foundation plan
- Schematic piping diagram
The Buyer shall provide the following data for information and use:
. Soil bearing capacity
. Dynamic characteristics of soil
2.2 Raw water:
Adopt the river water nearby the plant.
Water for exhaust boiler shall be treated according to the international standard and the Chinese standard (GB). Water for DG need not to be treated.
2.3 Fuel:
HSD (High Speed Diesel) / HFO (Heavy Fuel Oil) is the main fuel. The HFO need to be heated by the steam that supplied by steam exhaust gas boiler.
2.4 Cooling water:
Cooling water system for engine adopts close (two circuit) cooling system. Engine jacket cooling water uses fresh soften treated water, circulates by one engine driven water pump. Low temperature cooling water system adopts fresh water directly by electrical motor driven pump. Coolant in both circuit are cooled by the radiator.
2.5 Electrical:
2.6 Instrument & control:
Adopt central control system in the control room. All measure and control for generators can be carried out in control room. Others such as oil storages, pumps, boosters and radiators will be operated on site, and all alarm signals will be shown in control room.
3. General arrangement:
3.1 The main plant
The main plant will be arranged in 2 lines:
The first line is for the electrical control room, switchgear room, water soften treatment room and air compressor, air receiver. The second floor is for steam exhaust gas boilers and silencers, boiler is hypaethral layout. The distance of the columniation is 6 m; the span is 8 m, length is 84M and height is 5 m;
The second line is for DG, lube oil tank, booster, etc, the span is 18m, length is 84m; there is a traveling crane (10t) in the room.
a. Control room
The total area of control room is 672 square meters with length of 84m, width of 8m and height of 4 m. The roof of the control room is of reinforced concrete construction, and is flat roof that is convenient for installing equipments on it. One silencer and its bracket with weight of 1.2 ton are arranged for each generator, total are 12 sets, and total weight for 12 silencers is 14.4tons. An exhaust gas boiler with weight of 5 tons is arranged for every two generators, total is 4 boilers, and total weight for 4 boilers is 20 tons. For each boiler, girder for bearing the weight shall be arranged.
Inside the control room, there are HV switchgear room, LV control room, water soften treatment room and air compressor room. All HV and LV cables will be connected to switchgears or control panels through cable trenches in the control room.
Double deck sound insulation glazing with length of 1800 mm, width of 1500 mm, and thickness of 8 mm is installed on the control room wall facing to the alternator end of the generator. The bottom of glazing shall be 800 mm above the ground.
Ventilation for the control room adopts air conditioner.
b. Generator hall
The total area of steel construction main building is 1512 square meters with length of 84 m, width of 18m. The distance of the columniation is 6 m. A 10 tons double girder bridge crane with span of 16.5 m is installed in the generator hall. The installing height of columniation for crane railway is 7 m, and its total height is 9.6m. The maximum height of the main building is 12.8 m.
Main equipments in generator hall:
a. 12 sets of 3MW generators
Model: 3000GF; Rated power: 3000kW; Rated speed: 750r/min; Weight for each generator: 55 tons including diesel engine 31 tons, alternator 18 tons and engine frame base 4 tons, coupling and accessory about 2 tons .
b. Two sets of fuel booster modules for fuel viscosity control;
Weight for each fuel booster module; 2.3 tons
3.2 Radiator
Cooling radiator is used for the power plant. The radiator is plate outdoor installation multiple fan double layer type.
3.3 Oil storage
There are three 1300m3 HFO storages, two 150m3 buffer HFO tanks, one 640m3 DO storage, one 50m3 daily HFO tank, one 50m3 daily DO tank and one 50m3 sludge oil tank. HFO separators and fuel pump are installed in the separator and pump room.
Heavy fuel oil transported by fuel truck (about 30 ton) will be pumped to three HFO storages and two buffer HFO tanks. One HFO unloading pump station is installed in the room. HFO in the three HFO storages can be transferred to the buffer HFO tanks.
Diesel oil transported by fuel truck (about 30 ton) will be pumped to DO storage and daily DO tank. One DO unloading pump station is installed in the room.
For all HFO storages and tanks and sludge tank, steam coil pipes are installed inside and thermal insulations are provided outside.
Fuel temperature in HFO storage is recommended to be 50-60 centigrade degree, fuel temperature in buffer HFO tank to be 70-80 centigrade degree. The buffer HFO tanks are used for pre-separation of sludge and water contained in HFO and providing a suitable constant HFO temperature. Gravitational settling of water and sediment in HFO is an extremely slow process due to small density difference between HFO and the sediment. A large fuel oil surface area and a low viscosity are needed for the settling process. The volume of each buffer HFO tank is 150m3, which is enough for 24 hours continuous operation at rated load.
HFO in buffer HFO tank will be pumped to the separator modules. There are four separator modules in the separator and pump room. The separating capacity for each separator module is 5000 kilogram one hour. When four separator modules work together, the separating capacity is 20000 kilograms one hour. For whole power plant, the maximum HFO consumption one hour is about 9000 kilograms. The clean HFO will be pumped to daily HFO tank, and the sludge oil will be pumped to sludge oil tank through the sludge oil pump installed on separator module.
Heavy fuel oil in daily HFO tank and diesel oil in daily DO tank will be pumped to booster module in generator main building.
Fuel oil unloading and HFO purified equipments is installed in the aux. room at fuel storage area.
a. One set HFO unloading pump station
b. One set DO unloading pump station
c. Four sets HFO separator
4. System specifications:
4.1. DG system:
Rating of the D.G. set
Under above mentioned site conditions
-----------------------------------------------------------------------------------------------
Rating at Alternator Rating at
engine efficiency alternator
crankshaft terminal(MCR)
KWm ( % ) KWe KVA(0.8 pf)
-----------------------------------------------------------------------------------------------
Nominal 3310 96 3000 3750
Running
-----------------------------------------------------------------------------------------------
Note: COP rating will be 90 % of MCR
Gen-set model 3000GF1-3A
Manufacturer ND.
Rated voltage 11000V
Rated power factor 0.8 Lag
Phase 3
Frequency 50Hz
Rated speed 750rpm
Stable frequency (rev.) regulating rate ‘≤ 0.5%
Frequency (rev.) fluctuation rate ±0.5%
Transient voltage regulating rate +20~-15%
Stabilizing time 5S
Stable voltage regulating rate ±2.5%
Voltage fluctuation rate ±1%
Range of voltage setting 95%~105% Un
Voltage regulation method Brushless AVR
Gen-set rated power (PRP) 3000kW
1h power every 12h (LTP) 3300kW
Continuous power (COP) 2700kW
Rated power output fuel consumption 215+3% g/kWh
Lubrication oil consumption 1.2g/kWh at full load
Start time <5S
Enclosure IP23
Alignment method Flexible coupling
Installation method Individual frame rigid install
Overall dimensions: 9321x2715x3613mm
Weight 55T
4.1.1. 3MW diesel engine:
Technical particulars for the diesel engine are as follows:
Number of cylinders 8
Arrangement of cylinders In Line
Bore (mm) X Stroke (mm) 320 X 380
Type 4-stroke, direct injection, turbocharger, after cooler
Rotational speed 750 RPM
Mean effective pressure 22.5 Bar
at rated power & speed
Mean piston speed 9.5 m/sec.
Rotation seen from flywheel Clockwise.
Swept volume per cylinder 30.5 litres
Combustion chamber volume 2.35 litres
Compression ratio 13:1
Max. combustion pressure 155 bar (at rated power/speed)
Power rating
Rated power under ISO Conditions
Maximum continuous rating (MCR) 4500 HP
at engine crankshaft
Corresponding rotational speed 750 RPM
Under the following limiting ambient conditions :
Air temp. at turbocharger inlet 45 deg. C
Water temp. at charge air cooler inlet 32 deg. C
Deration to power applicable for engine 0 %(nil)
Beyond the abovementioned limiting conditions, deration to power as per ISO 3046 will be applicable.
Rated Power under site conditions mentioned above: Maximum continuous rating (MCR) 3600HP at engine crankshaft
The engine should be capable of accepting a sudden load as per the guidelines in ISO-8528-5-1993(e). As per this standard, the maximum sudden load increase stages are
Baseload % Sudden load increase to %
--------------------------------------------------------------------------------
1st Stage 0% 40 40%
2nd Stage 40% 30 70%
3rd Stage 70% 20 90%
4th Stage 90% 10 100%
During each of the above-mentioned stages of sudden loading, the transient speed drop will be restricted to a maximum value of 10% of the rated speed.
4.1.2. Alternator
The Alternator is self-excited, brush-less type in two bearing construction with single shaft extension and IP 23 enclosure. The alternator is fitted with bearing temperature detectors.
Technical data of alternator
- Rated output kVA 3750 KVA
- Power factor 0.8 lag
- Max. Alternator output at site 3000 KW
- Duty Continuous
- Rated speed 750 RPM
- Rated voltage 11000 V
- Rated Current 196.8A
- Efficiency at 100% load and 0.8 PF ‘≥96%
- Direction of rotation clockwise
- Number of poles 8
- Rated frequency 50 Hz
- Over-speed 20% for 2 minutes
- Overload capacity and duration 10%, for max. 1 hr in every 12 hrs
- Insulation class F
- Enclosure IP 23
- Temp. rise class F
- Excitation and AVR type Brush-less, AVR
- Connection Star
NOTE
Alternator design considers harmonics in load.
4.2 Governor system for DG
Woodward 2301D digital control and UG15 actuator are adopted for load sharing and speed control of diesel generator.
The 2301D is a microprocessor-based digital control. The control is housed in a sheet-metal classis and consists of a single printed circuit board. The 2301D is configured using a computer with Woodward Watch Window software. The computer connects to the 2301D through a 9-pin connector (RS 232 port). The control operates from a 24Vdc supply. The actuator output, one analog input, and one analog output are configurable. The 2301D features dual dynamics and soft load transfer, to and from a bus. The 2301D includes one load sensor circuit, one actuator driver, one MPU speed sensor, one configurable analog output, one configurable analog input, eight discrete inputs and four discrete outputs. The 2301D operates within a range of -40 to +70°C.
The 2301D provides load sharing and speed control of diesel generator. The 2301D has four operating modes -- speed control, isochronous load sharing, droop base load, and isochronous base load.
Woodward UG-15 is a hydraulic powered electric actuator. The UG-15 provides the muscle for 2301D. The UG-15 takes a given electrical input signal and converts it to a proportional hydraulic output-shaft position to control engine flow.
4.3 Fuel Circuit system
Type of fuel:
The engines are suitable for operation on DO (Diesel Oil) / HFO (Heavy Fuel Oil or Furnace Oil with maximum viscosity 380 cst at 50 deg. C.);
While starting or stopping the engine DO (Diesel Oil) is used as fuel. When the water temperature at inlet to engine is more than 60 deg.C and the HFO (Heavy Fuel Oil) is heated to the required temperature, the fuel can be changed from DO to HFO through a change-over oil tank.
Equipment fitted on the engine:
- Individual fuel injection pump for each cylinder with fuel rack & linkages.
- Individual injector fitted on each cylinder head.
- High-pressure injection pipes
- Main fuel rails for feeding and return.
- High-pressure pipe connection for each cylinder
Equipment delivered loose:
1) Four HFO separator modules
2) Two fuel viscosity control modules (booster) consisting of:
Two electric motor driven fuel feed pump (one for working, one for standby);
Two electric motor driven fuel booster pump (one for working, one for standby);
One duplex type coarse filter;
One pressure-regulating valve;
One steam heater for HFO;
One flow meter for HFO;
One 3 way fuel changeover valve;
One viscometer & temp controller;
One emergency pressure safety valve;
One duplex type fine filter;
One mixing vessel with safety valve;
One pressure-regulating valve in fuel return;
3) Complete interconnecting piping with flanges, fasteners, valves, non-return valves, bosses, supports, etc as necessary.
Fuel consumption:
The hourly rate of fuel consumption per Metric Horse Power delivered at the crankshaft flange at rated power & speed (after running in of the engine & for engine with driven raw water, fresh water & lube oil pumps) is 195g/kWh, when engine operates at Maximum Continuous Rating (MCR).
FUEL CONSUMPTION (with 3 driven pumps)
====================================================
DN8320ZD6 Consumption at engine Cr. shaft
750rpm g/kWh
====================================================
100% Load 195.00
SITE -----------------------------------------------------------------------------
75% Load 200.00
CONDITION-------------------------------------------------------------------------
50% Load 210.00
====================================================
The values are subject to a 3% tolerance and apply when burning fuel with a net calorific value of 10,200 KCal/Kg minimum.
CLIMATIC CONDITIONS
ISO Conditions
Air temp. to turbocharger inlet 25 deg. C
Atmospheric pressure 750 mm Hg
Relative humidity 30 %
Water temp. at charge air cooler inlet 25 deg. C
Site Conditions (Assumed)
Air temp. to turbocharger inlet 45 deg. C
Atmospheric pressure 750 mm Hg
Relative humidity 60 %
Water temp. at Radiator outlet 52 deg. C
The heavy fuel oil from daily HFO tank and diesel oil from daily DO tank will be pumped to the mixing vessel on the booster module through two fuel feed pumps. After heated by steam, the heavy fuel oil (or diesel oil) with constant viscosity about 10-14 cst will be pumped to fuel main pipe. The booster module is used for controlling viscosity and supplying fuel for generators. Fuel-supplying capacity for each booster module is 4000 kilograms one hour (Maximum feed capacity is 6000kg one hour, return oil is 2000kg one hour). Return oil from each generator will back to the mixing vessel through return main pipe.
Fuel change between HFO and DO can be achieved through the 3-way valve on booster module.
4.4 Lube oil circuit system
Oil sump capacity (ltr)
The engine is equipped with a dry sump attached to the bottom of the crankcase. The lube oil for the engine is stored in a separate tank positioned away from the engine. This arrangement offers much more reliability than the wet sump arrangement.
The total oil capacity of this lube oil tank is 2000 ltrs.
Lube oil consumption
The average lube oil consumption is 0.8gm/kwh (+/- 0.2 gm/kwh) at MCR at crankshaft for a well-run engine.
Equipment fitted on the Engine:
- One engine driven lube oil supply pump
- One engine driven lube oil transfer pump
- One pressure-regulating valve
- One lube oil thermostatic valve (option)
- Complete interconnecting piping with flanges, fasteners, valves, non-return valves, bosses, supports, etc as necessary.
Equipment delivered loose:
- 12 tanks for lube oil (2000 ltrs capacity) with interconnections to the engine
- 12 electric motor driven lube oil-priming pumps (option)
- 12 manual lube oil-priming pumps
- 12 lube oil coolers
- 12 centrifugal lube oil filters (FLL75 bypass type)
- 12 lube oil duplex type filters
- Complete interconnecting piping with flanges, fasteners, valves, non-return valves, bosses, supports, etc as necessary.
4.5 Starting air circuit system
The DG is started by the compressed air.
Two air compressors, two 2.5m3 air receivers and one top up are arranged for the power plant, the capacity of each air receiver is 2500 liters, which is enough for starting one generator 30 times without intermediate refilling of the receiver.
High-pressure compressed air about 3 Mpa from the air receivers will be sent to 12 generators through air main pipe, and also be sent to HFO separator modules and booster modules through pressure reducers for control air.
Equipment fitted on the engine:
Compressed air starting equipment including:
- One rotary distributor
- One air-starting valve in each cylinder head
- Connecting air piping on the engine
Equipment delivered loose:
- Two air compressors
- Two air receivers
- One top up
- Complete interconnecting piping with flanges, fasteners, valves, bosses, supports, etc as necessary.
4.6 Cooling water circuit system
Radiator is arranged for each generator, and an electric water pump is arranged for the water circuit system.
Drawn by the electric water pump from the radiator, the cooling water flows to the air cooler, and to the injector cooling oil cooler and to the lube oil cooler, and then enters the inlet water main pipe and the turbocharger. The cooling water is discharged out through the outlet water main pipe. Finally the water is cooled in the radiator.
Equipment fitted on the engine:
- One lube oil cooler
- One injector cooler
- One water-cooled charge air cooler
Equipment delivered loose:
- 12 radiators (outdoor)
- 12 electric water pumps
- Complete interconnecting piping with flanges, fasteners, valves, bosses, supports, etc as necessary.
4.7 Exhaust gas system
The exhaust gas from diesel generator flows to exhaust gas pipe (DN400), pass a tee joint, and then divides two ways. One flows to silencer through a butterfly valve, another flows to exhaust gas boiler. When the exhaust gas boiler works, the butterfly valve for silencer will close and the butterfly valve for exhaust gas boiler will open, and then exhaust gas will vent from the chimney on the boiler. When the boiler cannot work normally or the boiler need to be stopped, the butterfly for boiler will close and the butterfly valve for silencer will open, and then exhaust gas will a silencer and then vent from the chimney.
Four steam exhaust gas boilers are arranged for the power plant, each one will connect with two generators. One exhaust silencer (Residential type) is fitted to the each generator.
Equipment fitted on the engine:
- Lagged set of exhaust manifold with expansion bellows
- One ABB turbocharger.
- Exhaust outlet connection with expansion bellow.
Equipment delivered loose:
- 12 exhaust silencers
- 4 exhaust gas boilers
- Insulation /lagging/cladding for exhaust ducting
- Complete interconnecting piping with flanges, fasteners, t-joints, butterfly valves, bosses, supports, etc as necessary.
4.8 Steam system
Four exhaust gas boilers are arranged on the roof of control room. Heat exchange area for each boiler is 112 m2, steam capacity for each boiler is 1000kg one hour at 170 degree centigrade and 0.7 Mpa. Steam from boilers will flow to steam main pipe and divide to separator and pump room, oil storage and main building through main steam distributor and steam distributors. The main steam distributor is located on the roof of control room, and other steam distributors are located beside the equipments need to be heated.
Drain trap is arranged on the end of steam pipe for equipment need to be heated, condensation water will not recover.
Equipments for steam system:
- 4 exhaust gas boilers
- 8 water feed pumps
- Steam distributors
- Insulation /lagging/cladding for steam pipes
- Complete interconnecting piping with flanges, fasteners, t-joints, valves, bosses, supports, etc as necessary.
4.9 Water soften system for exhaust gas boiler
Two water soften equipments are arranged for the power plant, water treatment capacity for each equipment is 5000kg one hour. One works, another for standby.
The water soften equipment adopts resin exchanger treatment system.
Equipments for water soften system:
- 2 water soften equipments (double module)
- 2 water feed pump
- One water tank (civil construction by the buyer)
- Complete interconnecting piping with flanges, fasteners, valves, bosses, supports, etc as necessary.
4.10 Electrical system
The Buyer takes responsibility to transmit power from the main outgoing panel to user position.
Lighting, air conditioner, fire fighting and others shall be considered by the buyer during civil work.
4.10.1 H.V. system
Twelve 3MW/11kV HFO generators will work in parallel and supply electricity to one 11KV bus-bar through one generator outgoing main switchgear, and output with a main outgoing panel.
11kV generator system
Twelve 3MW/11kV diesel generators are arranged for the power plant. For each one generator, the standard configure includes one switchgear for generator, one control and operation panel, one local control desk.
The neutral of generator is earthed through surge arrestors (standard delivery in China).
All 12 generators are connected with a single bus-bar. An 11kV bus-bar PT panel is arranged for parallel operation. All 11kV H.V. panel adopt KYN28A-12 metal-enclosed removable switchgears, the switch for generator switchgear adopts VS1 vacuum circuit breaker (with truck), its rated current is 630A, and rated short-circuit breaking current is 31.5KA.
The generator bua-bar connects with one 11kV outgoing panel. The switch adopts VS1 vacuum circuit breaker (with truck), its rated current is 2000A, and rated short-circuit breaking current is 50KA.
Generator switchgear
Vacuum circuit breaker is used to deliver the generated output power to the generator single bus-bar.
Major Components
1) 3 pole fixed type electrically operated Vacuum Circuit Breaker
2) Metering / Protection CT and PT
3) Kw / Kwh meter
4) Meters, indicators
5) DMR
Metering devices
6) Ammeter with selector switch
7) Voltmeter with selector switch
Indications
8) VCB ON
9) VCB OFF
10) System SOE
Controls Possible
11) Local / Remote control selection
12) VCB ON/OFF
Current Transformers
13) Differential CT
14) Two core Metering / Protection CT
Potential Transformers
15) Two core potential transformer for Metering/Protection
Control and operation panel
Control Panel provides necessary Monitoring, Control and Protection functions for the DG set. It is located in the DG control room.
Major Component
1) Programmable Logic Controller (PLC)
2) Speed Governor controller
3) Automatic Voltage Regulator
4) Meters, indicators, hour counters
5) Push buttons, selector switches
6) Engine Frequency Monitoring Unit
Metering Devices
7) Analog Engine RPM meter
8) Ammeters (3 nos.)
9) Voltmeter with selector switch
10) Frequency meter
11) PF meter
12) Analog Excitation fundamental ammeter
13) Analog Excitation harmonics ammeter
14) Counter for running hours
Generator Protections
15) Differential
16) Voltage controlled over current
17) Under / Over voltage
18) Under / Over frequency
19) Very high Alternator bearing temperature
20) Reverse power
Status Indications
21) Low lube oil priming pressure
22) Breaker engaged
23) Engine start permission
24) Unit ready for excitation
25) Ready for excitation
26) DG breaker ON
27) DG breaker OFF
28) DG breaker Tripped
Alarm Indications
29) Low lube oil pressure
30) Low water pressure
31) Low fuel pressure
32) High lube oil temperature
33) High water temperature engine outlet
34) High fuel temperature engine inlet
35) Alternator bearing temperature high
Trip Indications
36) Very low lube oil pressure
37) Very high lube oil temperature
38) Very high water engine outlet temperature
39) Engine over speed
40) Emergency stop
41) Differential
, , 42) Under / over voltage
43) Under / over frequency
44) Voltage controlled over current
Controls possible
- Engine speed raise/low
- Engine start
- Engine normal and emergency stop
45) Excitation ON / OFF
46) Excitation adjust
47) Breaker control
- Fault indication
- Lamp test
- Reset
Local Control Desk
Function
Local Control Desk (LCD) is provided for monitoring Pressure and Temperature parameters of the engine. Also starting, stopping and speed control of engine is possible in local Control operation mode. It is located near the engine.
Major Components
1) Pressure gauges, switches
2) Temperature indicators or scanner
3) Scanner for Engine exhaust temperatures
4) Push buttons, indicating lamps, selector switches
5) Flasher
Pressure Gauges
6) Lube oil filter inlet pressure
7) Lube oil filter outlet pressure
8) Lube oil cylinder head inlet pressure
- Fuel engine inlet pressure
- Starting air pressure
- Water engine inlet pressure
Pressure Switches
9) Lube oil engine inlet pressure
Temperature Indicators / scanner
10) Lube oil engine inlet temperature
11) Lube oil engine outlet temperature
12) Water engine outlet temperature
13) Water engine inlet temperature
14) Exhaust gas temperature for each cylinder
15) Exhaust gas temperature for turbocharger
16) Water temperature for each cylinder
Misc. Indications
- Engine RPM indicator
- Common engine alarm
- Engine start permission
Controls possible from LCD
- Local / remote mode
- Engine start / stop
- Flasher off
17) Engine speed raise / low
- Emergency stop
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