Course No. ME402
Group No. A24
Experiment No. 05 Name of the Experiment: STUDY OF BUET POWER PLANT.
Date of submission: 31.05.2011 Date of performance: 23.05.2011
Name: Raihan Tayeb Student No: 0610070 Dept: ME Sec: A Level: 4 Term:1
Objective:The objective of this experiment is to study the different systems of the generators of the BUET power plant.
Gas Engine Specifications:Manufacturer and Model Cycle and Ignition Bore mm (inch) Stroke mm (inch) Displacement L (cu in) Aspiration Compression ratio Shipping Weight (dry) kg (lb) (Including engine, generator and rails) Cylinders and arrangement Rotation (flywheel end) Inlet valve lash Exhaust valve lash Firing order Standard optional Compression stroke Standard optional Exhaust stroke Standard optional Caterpillar G3516 LE SCAC 4-stroke-cycle, spark-ignited engine 170 (6.7) 190 (7.5) 69.0 (4210) Turbocharged-After cooled 11:1 11813 (26043) 65 degree V-16 Counterclockwise rotation is standard /clockwise rotation is optional. 0.51 mm (0.020 inch) 1.27 mm (0.050 inch) 1-2-5-6-3-4-9-10-15-16-11-12-13-14-7-8 1-6-5-4-3-10-9-16-15-12-11-14-13-8-7-2 Inlet valves: 1-2-5-7-8-12-13-14 Exhaust valves: 1-2-3-4-5-6-8-9 Inlet valves 1-2-5-6-7-8-13-14 Exhaust valves 1-2-3-4-5-6-9-10 Inlet valves: 3-4-6-9-10-11-15-16 Exhaust valves: 7-10-11-12-13-14-1516 Inlet valves 3-4-9-10-11-12-15-16 Exhaust valves 7-8-11-12-13-14-15-16
CATERPILLAR SR4B GENERATOR Specifications:
Rating Type Construction Insulation Enclosure Alignment Over speed capability Waveform Paralleling capability Voltage regulator Voltage regulation Voltage gain TIF THD
CONTINUOUS 1030 ekW 1287 kVA 50 Hz 1500 rpm 400 Volts Brushless PM excited, solid state automatic voltage regulator Single bearing, two bearings three phase, wye connected Class H Drip proof IP 22, guarded Caterpillar pilot shaft 150% Less than 5% deviation. Standard with adjustable voltage drop 3 phase sensing with volts per hertz response Less than 1% Adjustable to compensate for engine speed droops and line loss Less than 50% Less than 5%
Picture of the Generator set:
Figure-1: Caterpillar Gas generator Set G3516 LE
Different systems of the engine:Different important subsystems of the engine includes:
a) b) c) d) e) f)
Air Supply System Fuel Supply System Lube Oil System Cooling System Exhaust System Starting System
Air Supply System:FD fan Air Cleaner Turbo charged after cooler Carburetor
Air is supplied from the atmosphere with the help of a FD Fan. Then the air is passed to the air cleaner for cleaning out dust or unwanted particles. Then the air is compressed and for cooling the compressed hot air after cooler is used. Then it send to the carburetor where it gets mixed with the fuel(NG) and goes to main cylinder.
Fuel supply System:Natural gas is being used as the fuel for the engines. These engines can be equipped with a high pressure gas fuel system or a low pressure gas fuel system. Three different fuel systems are available: 1. Low emission (LE) with high pressure gas. 2. LE with low pressure gas. 3. Standard (stochiometric) with high pressure gas. The engines can be equipped with a dual fuel system in one of the following configurations. A carburetor for high pressure gas and a carburetor for low pressure gas. Two parallel carburetors for low pressure gas. For low pressure gas engines, the carburetor is located between the air cleaner and the turbocharger. For high pressure gas engines the carburetor is located after the after cooler and above the throttle. A governor and an actuator control the carburetor. The governor maintains the engine rpm. Two following types of carburetors are available. 1. Fixed ventury 2. Adjustable jet These engines can use either the fixed venture or the adjustable jet. Standard engines and LE engines with high pressure gas the adjustable jet. The turbocharged after cooled engines are equipped with flame arrestors. The flame arrestors are installed at the entrance of each inlet port. They help to prevent backfire which can occur under the following circumstances: 1. Malfunction of ignition 2. Engine shut down.
The flame arrestors will extinguish the flame before the flame can ignite in the inlet manifold.
Lubrication System:Oil Pan Gear Pump Oil filter
A gear driven pump supplies the engine lube oil. The oil is cooled and filtered. A by pass valve provides unrestricted flow of lubrication oil to the engine parts if the oil filter elements become plugged. The by pass valve will open if the filter differential pressure reaches 40 Psi.
Cooling System:The standard cooling system has a gear driven centrifugal pump. Four temperature regulators regulate the temperature of the coolant. Water Tank Gear Driven Centrifugal pump
Water Jacket Flow Chart: Single System
The turbocharged engine has Separate Circuit after Cooled (SCAC). The after cooler is required to operate at one of the following three temperatures. The temperature depends on the engine rating and the application.
( 90F) ( 129 F) ( 158 F)
The temperature depends on the engine rating and the application.
After Cooler Water Tank Auxiliary Pump Oil Cooler Flow Chart: Combined System The cogeneration uses energy from the engines heat in addition to the electrical energy that is generated. The oil cooler is not in the jacket water circuit because the jacket water is too hot. The circuit for the oil and the circuit for the after cooler may be either a combined system, where the auxiliary pump circulates water through both the after cooler and oil cooler cores. The combined system uses a thermostatic control to regulate the oil temperature. This prevents over cooling. Jacket water for cogeneration can be supplied at temperature up to 127oC (260oF). The customer must supply a pump for circulating the heated jacket water. The temperature of the jacket water is controlled by the customer. For the engines that used for the landfill gas, the jacket water coolant temperature are maintained at approximately 110oC (230oF). This temperature depends on the design of the cooling system and the ambient conditions. This temperature is required in order to prevent condensation of the water vapor that is in the fumes of the crankcase. Condensation of the water enables acids to form. Acids are more likely to form if the fuel contains contaminants such as chlorides, fluorides and halides. Acids will cause severe internal damage to the engine. For engines that used landfill gas, the coolant that is supplied to the after cooler is maintained at a temperature of 54oC (129oF). This prevents condensation of moisture in the inlet air piping. Water Tank
Exhaust System:There are two exhaust valves on the cylinder head in the engine. These allow escaping the exhaust gas easily. There is a gas turbine (Turbocharger) attached in the exhaust line. The function of this turbine is to compress the inlet air after entering the engine cylinders. Normally the temperature of the exhaust gas is 650 C when it goes through the individual pipe line. When it goes to a common line then the temperature of the exhaust gas is reduced to 450 C .
(A) Inlet Valves (B) Exhaust Valves (C) Fly wheel
Fig: Valve Arrangements
Starting system:The engine starts by battery, here two motor is used and 24 DC supply is needed. For starting the engine we place the control switch (ECS) (2) to the LOCAL position. The engine will start and run at the preset parameters. The parameters ate controlled by the switch gear. For stopping the engine we turn the engine control switch (ECS) (2) to the OFF position and the will stop.
Starting Sequence:The following steps are performed to start this engine.
Before starting, all inspections are performed. The engine control switch (ECS) is turned to the MAN START position. If the ECS (2) is in this position, the engine will start and run. When the engine starts, the engine fault circuits are functional. If a fault occurs, the engine will automatically shut down. After being shut down by a fault, these steps have to followed in order to restart the engine. a. To correct the fault condition. b. To turn the engine control switches to the OFF / RESET position. c. Refer to initial condition in order to restart the engine. After the engine starts and the system have stabilized, the load is applied. The frequency of the generator is regulated by using one of the following devices: a. The optional governor switch. b. The optional speed potentiometer. c. The manual governor control lever on the engine.
Stopping Sequence:The following steps are performed to stop this engine,
The load is removed from the engine. In order to cool the engine at high idle and no load, the engine control switch is turned to the STOP position. This will allow the engine to run for the preset cool down time before shut down For cooling down the engine at no load the engine speed is reduced to low idle. On 60 Hz units, low idle is approximately 66% of the full load speed. If the governor has an electric motor, the governor switch is pushed down until low idle is achieved. On electronic governors, the speed potentiometer is turned down until low idle is achieved. For manual governors, the governor control lever is moved to the low idle position. While the engine is at the low idle, the engine oil level is measured. Oil level must be maintained between the ADD and FULL marks on the Engine Running side of the dipstick. In order to allow the engine to cool down, the e