GMB Polytechnic

Report on Industrial Visit at G.P.P.C. Kovaya.

7, March, 2018.

For Semester 4 students

Industrial visit was carried out at . On 7,March,2018. Especially for semester 4th

student.

The main objective behind the visit was to make student aware about how various

activities related to Machine and their Structure, Deferent types Machines work? & How

they generate electricity?.

I along with 29 students left for visit at 10 a.m. and took about one hour to cover the

distance. The company is located in Kovaya

SAFTY INSTRUCTIONS

To wear safety helmet which were received from safety office and there

we recived seafty instructions and ppt was made by the HR department.

FIRE AND SAFTY

Class A - fires involving solid materials such as wood, paper or textiles.

Class B - fires involving flammable liquids such as petrol, diesel or oils.

Class C - fires involving gases.

Class D - fires involving metals.

Class E - fires involving live electrical apparatus. (Technically ‘Class E’ doesn’t exists

however this is used for convenience here)

Class F - fires involving cooking oils such as in deep-fat fryers.

Types of Fire Extinguisher :-

(1) Water & Foam

The water component of this extinguisher removes the heat of the fire, while the foam

component removes the oxygen.

Works For: Class A fires only

(2) Carbon Dioxide (CO2)

Carbon dioxide replaces the fire’s oxygen and, as the gas is contained under pressure it

creates a cold discharge upon release, which removes the heat of the fire too.

Works For: Class B and C fires

(3) Dry Chemical

This extinguisher removes the chemical reaction of a fire, and is the most used of all fire

extinguishers because of its versatility across multiple classes.

Works For: Class A, B and C fires (multi-purpose); Class B and C (ordinary)

SAILENT FEATHER OF PLANT

(1) CO2 flooding system

(2) High violent and medium violent spray system

CHEMICAL USED IN GPPC SITE

(1)High speed diesel

(2)Lime

(3)Fe Cl3

(4)CO2

(5 ) Hydrogen

Theory of operation of gas turbine

In an ideal gas turbine, gases undergo four thermodynamic processes: an isentropic compression,

an isobaric (constant pressure) combustion, an isentropic expansion and heat rejection. Together,

these make up the Brayton cycle.

In an ideal gas turbine, gases undergo four thermodynamic processes: an isentropic compression,

an isobaric (constant pressure) combustion, an isentropic expansion and heat rejection. Together,

these make up the Brayton cycle.

Brayton cycle

In a real gas turbine, mechanical energy is changed irreversibly (due to internal friction and

turbulence) into pressure and thermal energy when the gas is compressed (in either a centrifugal

or axial compressor). Heat is added in the combustion chamber and the specific volume of the

gas increases, accompanied by a slight loss in pressure. During expansion through the stator and

rotor passages in the turbine, irreversible energy transformation once again occurs. Fresh air is

taken in, in place of the heat rejection.

Station or Unit Auxiliary Transformer

The Station Auxiliary Transformer is connected to the generator output by a

tap off of the Isolated Phase Bus Duct. The high voltage winding of the

transformer is designed to match the generator output voltage which is

22,000 Volts or 22KV in this example. This particular transformer is

shown as a three winding transformer. It has a primary winding and two

separate secondary windings at different voltages. This allows the station

to have two different voltage levels one at 6900 Volts or 6.9kV and the

other at 4160 Volts or 4.16KV. The higher voltage afforded by the 6.9KV

windings allows for the use of similar higher voltage motors for large

pumps or fans. The higher voltage motors offer several advantage over

4.16KV motors such as higher starting torques and lower full load

currents.

CONDENSING SYSTEM IN PLANT

In thermal power plants, the purpose of a surface condenser is to

condense the exhaust steam from a steam turbine to obtain maximum

efficiency, and also to convert the turbine exhaust steam into pure water

(referred to as steam condensate) so that it may be reused in the steam

generator or boiler as boiler feed water.

THREE PHASE SYSTEM

Three-phase electric power is a common method of alternating current

electric power generation, transmission, and distribution. It is a type of

polyphase system and is the most common method used by electrical

grids worldwide to transfer power. It is also used to power large motors

and other heavy loads.

Gas Turbine Basics

Gas Turbines

Types

How They Work

Applications

Components of Plant

Flow Paths

Operation

Gas Turbine Applications

Simple Cycle

Combined Cycle

Cogeneration

Types of Gas Turbine Plants

Simple Cycle

Operate When Demand is High – Peak Demand

Operate for Short / Variable Times

Designed for Quick Start-Up

Not designed to be Efficient but Reliable

Not Cost Effective to Build for Efficiency

Combined Cycle

Operate for Peak and Economic Dispatch

Designed for Quick Start-Up

Designed to Efficient, Cost-Effective Operation

Typically Has Ability to Operate in SC Mode

Principles of Operation

Open Cycle

(Also referred to as simple cycle)

The energy contained in a flowing ideal gas is the sum of enthalpy

and kinetic energy.

Pressurized gas can store or release energy. As it expands the

pressure is converted to kinetic energy.

Brayton Cycle – Gas Turbine Cycle

Principles of Operation

Compressor

As air flows into the compressor, energy is transferred from its

rotating blades to the air. Pressure and temperature of the air

increase.

Most compressors operate in the range of 75% to 85% efficiency.

Combustor

The purpose of the combustor is to increase the energy stored in

the compressor exhaust by raising its temperature.

Turbine

The turbine acts like the compressor in reverse with respect to

energy transformation.

Most turbines operate in the range of 80% to 90% efficiency.

Gas Turbine Components & Systems

Combustion System

Silo, Cannular, Annular

Water, Steam, DLN

Turbine

Multiple Shaft, Single Shaft

Number of Stages

Material and Manufacturing Processes

Exhaust System

Simple Cycle Stack

Transition to HRSG

Generator

Open-Air cooled

TEWAC

Hydrogen Cooled

Starting Systems

Diesel

Motor

Static

Combustion Turbine Fuels

Conventional Fuels

Natural Gas

Liquid Fuel Oil

Nonconventional Fuels

Crude Oil

Refinery Gas

Propane

Synthetic Fuels

Chemical Process

Physical Process

Typical Simple Cycle CT Plant Components

Prime Mover (Combustion Turbine)

Fuel Supply & Preparation

Emissions Control Equipment

Generator

Electrical Switchgear

Generator Step Up Transformer

Starting System (Combustion Turbines)

Auxiliary Cooling

Fire Protection

Lubrication System

Combining the Brayton and Rankine Cycles

Gas Turbine Exhaust used as the heat source for the Steam Turbine

cycle

Utilizes the major efficiency loss from the Brayton cycle

Advantages:

Relatively short cycle to design, construct & commission

Higher overall efficiency

Good cycling capabilities

Fast starting and loading

Lower installed costs

No issues with ash disposal or coal storage

Disadvantages

High fuel costs

Uncertain long term fuel source

Output dependent on ambient temperature