Engine Expt 5

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BANGLADESH UNIVERSITY OF ENGINEERING & TECHNOLOGY Course No.: ME 402 Course Title: INTERNAL COMBUSTION ENGINES SESSIONAL Experiment No.: 5 Name of the Experiment: Study of BUET Power Plant Date of Performance 23/05/2011 Name: Aashique Alam Rezwan Student No.: 06 10 012 Date of Submission 30/05/2011 Section: “A” Group: A 12 Dept: Mechanical Engineering

Transcript of Engine Expt 5

Page 1: Engine Expt 5

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BANGLADESH UNIVERSITY OF ENGINEERING & TECHNOLOGY

Course No.: ME 402

Course Title: INTERNAL COMBUSTION ENGINES SESSIONAL

Experiment No.: 5

Name of the Experiment:

Study of BUET Power Plant

Date of Performance

23/05/2011

Name: Aashique Alam Rezwan

Student No.: 06 10 012

Date of Submission

30/05/2011

Section: “A” Group: A12

Dept: Mechanical Engineering

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Experiment No.: 5

Name of the Experiment:

Study of BUET Power Plant

Objectives:

The objectives of this experiment are as follows

Study the different system of the generator of the BUET power plant

Analyze the performance data supplied

To plot Exhaust gas temperature Vs Power graph

To plot Bsfc Vs Bkw graph

Name Plate Data

Caterpillar Gas Generator Set

G3516 Lean Burn Low Energy Gas

Continuous 1030 ekW 1287 kVA

50 HZ 1500 RPM 400 VOLTS

Engine Specification

CAT LEAN BURN GAS ENGINE

G3516 LE SCAC 4-stroke-cycle, spark-ignited engine

Number of Cylinders V16

Bore mm (inch) 170 (6.7)

Stroke mm (inch) 190 (7.5)

Displacement L (cu in) 69 (4210)

Aspiration Turbocharged-After cooled

Compression ratio 11:01

Cylinders and arrangement 65 degree V-16

Rotation (flywheel end) Counterclockwise rotation is standard

Inlet valve lash 0.51 mm (0.020 inch)

Exhaust valve lash 1.27 mm (0.050 inch)

Firing order

Standard 1-2-5-6-3-4-9-10-15-16-11-12-13-14-7-8

Optional 1-6-5-4-3-10-9-16-15-12-11-14-13-8-7-2

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Generator Specification:

CAT SR4B GENERATOR

Frame Size 697

Excitation Permanent Magnet

Construction Star-Delta

Pitch 0.7333

Number of Poles 4

Number of Bearing 1

Number of Leads 6

Insulation Class H

IP Rating Dip proof IP22

Alignment Pilot Shaft

Over Speed Capability - % or Rated 125%

Wave form deviation line to line, no load Less than 3.0%

Voltage Regulator CDVR

Voltage Level Adjustment +/- 5.0%

Voltage Regulation, Steady State +/- 0.5%

Voltage Regulation with 3% speed change +/- 0.5%

Telephone Influence Factor Less than 50

Different Systems of the Engine:

Air Supply System:

The air is taken from the atmosphere with the help of and FD fan. The air is used for the

prime mover of the fuel. It helps burning the fuel in the engine. The air is first cleaned by an

air cleaner, and then a turbo charger after cooler is used to compress the intake air and cools

the air. Then the air is passed to the carburetor for mixing with fuel.

Fuel Supply System:

The engines have the ability to burn a variety of gaseous fuels. The 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.

FD Fan Air Cleaner Turbo

charged after cooler

Carburetor

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The LE engine with high pressure gas requires a gas pressure within a range of 207 to 310

kPa (30 to 45 psi). The air/fuel ratio is adjusted so that there is excess oxygen in the engine

exhaust. This reduces the NOx emission.

The LE engine with low pressure gas requires a gas pressure within a range of 10 to 34 kPa

(1.5 to 5 psi).

The standard engines require gas pressure within a range of 138 to 172 kPa (20 to 25 psi).

The nominal air/fuel ratio results in approximately two percent of free oxygen in the exhaust.

The standard engines are available with natural aspiration or turbocharged with after cooling.

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 cooled

and above the throttle. A governor and an actuator control the carburetor. The governor

maintains the engine rpm. The two following types of carburetors are available.

1. Fixed venturi

2. Adjustable jet

The following pressure gas 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. The flame arrestors help to prevent backfire.

Backfire can occur in 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:

The engine lubrication oil is supplied by a gear driven pump. The oil is first filtered before

supplying to the engine bearing. 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 275 kPa (40 psi).

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Engine Lubricating System

Cooling System:

The standard cooling system has a gear driven centrifugal pump. Four temperature regulators

regulate the temperature of the coolant.

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.

► 32 C 90 F

► 54 C 129 F

► 70 C 158 F

Oil Pan

Strainer

Gear Pump

Oil Filter

Engine Parts

Water Tank

Gear Driven Centrifugal

Pump

Water Jacket

Engine Parts

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Water TankAuxiliary

Pump

After Cooler

Oil Cooler

Water Tank

The cogeneration applications energy from the engine’s heat is used in addition to the

electrical energy. 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, 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 (260

oF). The user

must supply a pump for circulating the heated jacket water. The temperature of the jacket

water is controlled by the user.

Exhaust System:

In this engine, there are two exhaust valves on the cylinder head. These allow escaping the

exhaust gas easily. There is a gas turbines attached in the exhaust line. The function of this

turbine is to compress the inlet air after entering the engine cylinders.

13579111315

16 14 12 10 8 6 4 2

C

A B

(A) Inlet Valves (B) Exhaust Valves (C) Fly wheel

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Normally the temperature of the exhaust gas is 650when it goes through the individual pipe

line then when it goes to a common line then the temperature of the exhaust gas is reduced to

450 .

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 are 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.

Generator:

1. Type:

Brushless PM excited

Solid State

Automatic Voltage regulator

Star-Delta connected

2. Output Voltage:

Voltage regulator: 3 phase sensing with Volts per Hertz response

Voltage regulation: Less than 1%

Voltage gain: Adjustable to compensate for engine speed droop and line loss

Output Voltage: 420 voltage

Starting Sequence:

To start this engine, the following sequential steps are performed.

1. Before starting, all inspections are performed.

2. The engine control switch (ECS) is turned to the MAIN START position. If the ECS (2) is

in this position, the engine will start and the engine will run.

3. When the engine starts, the engine fault circuits are functional. If a fault occurs, the engine

will automatically shut down.

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4. After being shut down by a fault, these steps have to follow to in order to restart the

engine.

5. After the engine starts and the system have stabilized, the load is applied.

6. The frequency of the generator is regulated by using one of the following devices:

1. The optional governor switch.

2. The optional speed potentiometer.

3. The manual governor control lever on the engine.

7. The voltage level of the governor is regulated with the voltage adjust rheostat.

Stopping Sequence:

To stop this engine, the following sequential steps are performed

1. The load from the engine is removed.

2. 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. If cooling down the engine at no load is not desired, proceed to the next step.

3. 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.

4. 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.

5. In order to allow the engine to cool down, the engine is run at low idle approximately five

minutes. After the engine cools, the engine control switch is turned to the OFF/RESET

position.

For Emergency Stopping:

For emergency stopping emergency stop push button to shut down the engine.

After the emergency stop push button is used to shut down the engine. It will be necessary to

reset the push button. In order to reset the push button pull out the button and rotate the

button in a clockwise direction.

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Before starting we check the emergency stop buttons that are locate on the engine junction

box. If the emergency stop button was used to stop the engine we reset the air shutoff.

Before start the engine correct the problem that makes necessary to stop the engine

emergency

Power distribution system:

The generators are operated in isochronous mode i.e. the supply frequency is kept constant.

When load increases, frequency drops. This drop is sensed by governor and it increases fuel

supply. When the 2 generators are operated simultaneously, they must be synchronized.

There are 7 substations for distributing power:

Main Substation 1

Main Substation 2

Main Substation 3

Dr. Rashid Hall substation

N.I. Hall substation-old

N.I. Hall substation-new

Academic Building Substation (Not operational)

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Data Sheet

Table-1: Data of Power Plant

Parameter Unit-1 Unit-2

Operational time (Hour) 15 15

Energy (MWH) 9.9 9.31

Load (%) 51.53 48.47

Total Gas consumption (Nm3) 3749

Gas consumption (Nm3) 1931.8597 1817.1403

Rate of Gas consumption (Nm3/hr) 128.79 121.14

Table: Performance of Unit-2

Time

(hrs)

Gas

Consumption

Nm3/hr

Electric

Power

Output

(kW)

Bkw Bsfc

(Nm3/Bkw-

hr)

Exhaust Gas

Temperature

Cooling

Water Inlet

Temperature

Cooling

Water Outlet

Temperature

0900

121.14

480 480 0.252 467.5 70 74

1000 620 620 0.195 457 70 76

1100 651 651 0.186 456 70 80

1200 695 695 0.174 458 70 76

1300 660 660 0.184 456.5 70 76

1400 636 636 0.190 478 70 76

1500 710 710 0.171 472.5 68 78

1600 744 744 0.163 471.5 68 80

1700 650 650 0.186 483 72 80

1800 605 605 0.200 485 68 76

1900 625 625 0.194 485.5 68 74

2000 612 612 0.198 484 66 72

2100 482 482 0.251 499 66 72

2200 475 475 0.255 450.1 66 74

2300 448 448 0.270 499 66 70

2400 422 422 0.287 503 66 70

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Graph:

440

450

460

470

480

490

500

510

400 450 500 550 600 650 700 750 800

Exh

au

st G

as

Tem

per

atu

re

(°C

)

Power

(kW)

Exhaust Gas Temperature Vs Power Graph

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

400 450 500 550 600 650 700 750 800

Bsf

c

(Nm

³/b

kw

.hr)

Bkw

(kW)

Bsfc Vs Bkw Graph

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Sample Calculation:

Gas meter reading at 01.04.08 = 3420109 Nm3

Gas meter reading at 02.04.08 = 3423858 Nm3

Operational Time from 01.04.08 to 02.04.08 = 15 Hours.

Gas Consumption at 15 hours = 3420109 – 3423858 = 3749 Nm3

Unit-1

Energy meter reading at 01.04.08 = 9054.50 MWH

Energy meter reading at 02.04.08 = 9064.40 MWH

Net energy = 9.9 MWH

Load Share = 9.9 / (9.9+9.31) = 51.53 %

Gas Consumption per hour = 128.79 Nm3/hr

Unit-2

Energy meter reading at 01.04.08 = 9419.88 MWH

Energy meter reading at 02.04.08 = 9429.19 MWH

Net energy = 9.31 MWH

Load share= 9.31 / (9.9+9.31) = 48.47 %

Gas Consumption per hour = 121.14 Nm3/hr

Observation no. 1

Time: 2000 Hours

Unit -2

Assuming, Standard condition and no loss

So, Electric Power Output (kW) = Bkw

Electric Power Output = 612 kW

Bkw = 612 kW

Stack left temperature = 497 ºC

Stack right temperature = 471 ºC

Exhaust temp = (497+471) / 2 = 484 ºC

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Discussion:

In this experiment, we have visited the BUET power plant, in the premises of BUET. It is

capable of generating 4MW power. There are 3 units. One 2MW unit and two units of 1MW

capacity. All of the unit run by Gas Powered Engine.

In starting of the engine, lubricating oil level is checked. And manually lubricating oil

pressure is increased to a certain pressure so that lubricating oil can reach every parts of the

engine. And there is 24V DC voltage source which provide power to the engine before the

engine couple with the generator.

There are several springs under the generator set to provide damping effect. The blue pipe

indicates that cool water goes in and red pipe indicates that hot water from engine goes out.

There is combined cooling tower in the power plant. Both of the 1MW unit there is induced

draft fan is used. In the 2MW unit, there is a forced draft fan in the cooling tower.

The load of the engine is never given higher than 80%. This increases the engine life. The

engines are never run under full load. This will hampers the engine and consequently the

power plant.

We know that exhaust gas temp is increased with the brake horse power. But in this case,

from exhaust gas temp Vs power graph, it can be seen that exhaust gas temp is decreased

with the power. The graph is not seems satisfactory, because the power was not change

uniformly with time. So exhaust gas temp was changed with power non-uniformly.

From the Bsfc Vs Bkw graph, it can be seen that, with the increase in Bkw, the Bsfc is

decreased. In general, we have seen that with the increase in Bkw, the Bsfc is decreased to a

certain value and then further it is increased for an internal combustion engine.

In general, from the BUET power plant power is supplied to the teacher’s residential area,

student’s residential hall, academic building etc. The power is supplied from 7.30 am to 12

am. And in the rest time, the power is supplied to BUET from DESA.

The study we performed in this experiment is very much necessary for a much wider

knowledge in power plant construction and operation. It helps me to clarify my theoretical

knowledge learned through the books. The complex mechanism of the power plant operating

process can’t be comprehended without the practical experience.