• No results found

220021enC Combined Cycle Power Plant Overview

N/A
N/A
Protected

Academic year: 2021

Share "220021enC Combined Cycle Power Plant Overview"

Copied!
27
0
0

Loading.... (view fulltext now)

Full text

(1)

(Single- and Multi-Shaft)

(Single- and Multi-Shaft)

Training Module

(2)
(3)

Table of Contents

List of Technical Aids ... 4

Module Objectives ... 5

Overview... ... 6

Gas Turbine Power Plant Overview ... 6

Gas Turbine Main Components and Functional Principle ... 7

Generator Components and Functional Principle ... 8

Steam Turbine Power Plant Overview... 10

Basic Components of a Steam Turbine Power Plant... 10

Combined Cycle Power Plant Overview... ... 11

Multi-Shaft Arrangement ... 11

Single-Shaft Arrangement ... 12

Overview of a Combined Cycle Plant for CHE Supply... 13

Multi-Shaft Arrangement ... 13

Overview of a Combined Cycle Plant for CHE Supply... 14

Single-Shaft Arrangement ... 14

(4)

List of Technical Aids

Definitions Enclosure Integral Standard Document

Attachment Attached Site-Specific Illustration or Document

Identification Description

(5)

Module Objectives

Upon completion of this section, the trainee is able to:

n State why combined cycle power plants are used in preference for supplying electric

energy.

n Explain why a gas turbine set includes:

n A turbine

n A combustion chamber 

n A compressor 

n Give the reasons why the main electrical energy supply chain contains:

n A generator 

n An exciter 

n Generator bushings

n A generator breaker 

n A main step-up transformer 

n A grid breaker 

(6)

Overview

CCPP as energy supplier

A relative newcomer to the field of energy supply is the combined cycle power plant (CCPP).

n CCPPs take the advantages of gas turbosets and steam turbosets and combine them in a

system that provides electric power at a much higher efficiency than is possible with either system operating alone.

This section will briefly describe the process of typical ALSTOM gas and steam turbine  power plants before summarizing how those processes are combined in a typical CCPP.

n The material does not describe all equipment, but rather focuses on major components,

which are essential to an understanding of the overall process.

(7)

Gas Turbine Main Components and Functional Principle

Figure 1 Gas Turbine

The gas turbine is composed of three processing elements:

n an air compressor 

n a combustion chamber and

n the turbine itself 

The turbine itself:

n Converts the thermal energy contained in the combustion gas into mechanical energy at

the coupling and

n Is the prime mover that drives the generator and the compressor.

n Is driven by hot, compressed combustion gas that strikes blading mounted on the rotor,

and causes it to turn.

n After the combustion gas passes through the turbine it is discharged to atmosphere and

is called exhaust gas

The combustion gas that drives the turbine is supplied by the combustion chamber. The latter  one:

(8)

Generator Components and Functional Principle

Figure 1 Generator

The generator:

n Is the driven machine and

n Converts the mechanical energy of the turbine into electrical energy.

n Is composed of 

n A non-movable part called the stator and

n A movable part called the rotor.

n The latter is coupled to the turbine rotor, either;

n directly or 

n through a rotational speed reduction gear 

The rotor:

n Is basically a magnet and

n Creates a rotating magnetic field inside the machine by means of the excitation or field

winding, often referred to simply as the rotor winding.

The strength of the magnetic field must be adjusted to correspond to the electrical power  output of the generator. The consequences of this measurement are:

(9)

Generator Components and Functional Principle (continued)

Figure 1 Exciter

The exciter provides the direct current (DC) for the windings of the generator’s rotating magnetic field.

n Two types of exciters are used:

n brushless and

n static

Both perform the same function.

Generator Bushings The generator’s bushings:

n Provide the connection that enables the electric energy of the generator to be delivered to

the outside world.

n Are mounted on the generator stator housing and

n Receive the high voltage (HV) output of the stator windings.

The Generator Breaker

The generator breaker provides the electrical connection between the generator’s bushings and the step-up transformer.

(10)

Steam Turbine Power Plant Overview

Basic Components of a Steam Turbine Power Plant

Figure 2 The supply of electricity from a steam power plant requires:

n a water steam cycle with:

n a boiler 

n a steam turbine

n a generator 

n an exciter 

n generator bushings

n circuit breaker and

n step-up transformer.

The role of each will be briefly described.

Boiler

Theboiler:

n Is a place where an energy conversion takes place, namely from chemical energy of the

fuel into heat energy.

n The latter one is carried by the combustion gas.

(11)

Combined Cycle Power Plant Overview

Multi-Shaft Arrangement

Figure 3.1 The objective of a combined cycle power plant with multi-shaft arrangement is to deliver 

only electricity.

To fulfil the above objective, the major components of a multiple shaft combined cycle  power plant are:

n One or more gas turbosets.

n One or more heat recovery steam boilers (HRSB).

n One or more steam turbosets.

n The rest of the water-steam cycle.

n The balance of plant equipment:

n mechanically and

n electrically.

n Control equipment.

The process begins when thegas turbosetis placed in operation.

n The gas turbine operates on a mixture of air and fuel, which is ignited in the combustion

chamber.

(12)

Multi-Shaft Arrangement (continued)

Exhausted steam is directed to acondenser, where it is converted to water called condensate.

The condensate is then directed to the feed water storage tank-deaerator. Here it is:

n Deaerated

n Preheated and

n Stored

The feed water is then used by the HRSB in the throughput demanded by gas turbineset electric power output.

Single-Shaft Arrangement

Figure 3.2 The objective of a combined cycle power plant with single-shaft arrangement is to deliver 

only electricity.

To fulfil the above objective, he major components of a single shaft combined cycle power   plant are:

n A gas turbine.

n An alternator.

(13)

Overview of a Combined Cycle Plant for CHE Supply

Multi-Shaft Arrangement

Figure 3.3 The objective of a combined cycle plant for CHE supply with multi-shaft arrangement is to

deliver simultaneously

n heat and

n electricity.

This process is known as combined heat and electricity (CHE) supply.

To fulfil the above objective, the major components of a multiple shaft combined cycle plant for CHE supply are:

n One or more gas turbosets.

n One or more heat recovery steam boilers (HRSB).

n One or more steam turbosets.

n One or more heating condensers.

n The rest of the water-steam cycle.

n The balance of plant equipment:

n mechanically and

n electrically.

(14)

Overview of a Combined Cycle Plant for CHE Supply

Single-Shaft Arrangement

Figure 3.4 The objective of a combined cycle plant for CHE supply with single-shaft arrangement is to

deliver simultaneously

n heat and

n electricty.

This process is known as combined heat and electricity (CHE) supply.

To fulfill the above objective, the major components of a single shaft combined cycle plant for CHE supply are:

n A gas turbine.

n An alternator.

n A self shifting and synchronizing (SSS) clutch.

n A water steam cycle, mainly composed of:

n A heat recovery steam boiler.

n A steam turbine alternator set.

n A condenser.

n A heating condenser.

n Condensate extraction pumps.

n A deaerator feedwater storage tank.

(15)

Control and Protection System Overview

Importance of automated control systems

Today's complex power plants operate at very high efficiency because of the sophisticated design of the equipment used.

n To reach these high levels of efficiency and reliability, automation systems have become

standard in the industry.

n ALSTOM's major control and protection systems are briefly outlined below.

n Details are provided in the respective gas and steam turbine modules.

Figures 1 and 4 EGATROL

EGATROL:

n Is the abbreviation for electronic gas turbine controller.

n Includes a sequencing program that automatically starts, “loads” and shuts down the gas

turboset and its auxiliaries while observing ALSTOM protective limitations.

n Regulates during operation, the gas turboset by positioning the fuel control valves based

on electric power output requirements.

n Includes a man machine interface (MMI):

(16)

Control and Protection System Overview (continued)

Figures 2 and 4 TURBOMAT

The TURBOMAT:

n Is the steam turboset sequencer.

n Is optional equipment.

n When supplied is used to automatically start-up, “load”, and shut-down the steam turboset

and its auxiliaries while observing ALSTOM limitations.

Figures 1 and 2 UNITROL

The UNITROL:

n Is the excitation system for the alternators.

n Includes a centerpiece that is the automatic voltage regulator (AVR). The latter one:

n Maintains the outlet voltage of the generator at a constant value.

n Influences the exciter and thereby the electric current through the windings of the

magnetic field.

n Has a back-up manual field current regulator (FCR). The latter one:

n Fulfills the same task but requires manual input from the operator.

n Adjusts the reactive electric power output of the generator, expressed in units of

(17)

Control and Protection System Overview (continued)

Figures 1 and 2 GSX or REG:

The generator protection system:

n Protects the generator and its associated equipment from abnormal operating conditions.

When the protection equipment detects a fault:

n The generator breaker is opened and

n The gas or steam control valves are tripped to their closed positions.

n Has the designation GSX or REG, depending the selected model.

Figure 4 BOILERMAT

Each HRSG has several function groups and drives. The BOILERMAT:

n Is the boiler controller.

n Coordinates different control functions of the HRSB like:

n start-up

n shut-down and

n open-loop controls

n This coordination is made in respect with the open-loop controls of the gas and steam

turbosets.

(18)

Control and Protection System Overview (continued)

Figure 4 BLOCKMASTER  

The BLOCKMASTER:

n Is the overimposed power plant controller.

n Ensures that each major component in the CCPP process is brought into service or 

removed from service in the proper sequence.

n Is also called UNITMASTER.

n Includes several MMIs:

n For receiving data from the process.

n To influence the process.

Summary

This section:

n Described the components used to deliver electricity from modern gas and steam turbine

(19)

 C   om  b i   n  e  d   C   y   c l    e  C   C  P  P   O v  e r  v i    e w P   ow  er  l    an  t    s   (    S i   n  gl    e- an  d  M  ul    t  i  - S  h   af    t   — — — — — — — — — — P   ow  er  l    an  t   r   ai  ni   n  g  C   en  t    er  — — — — — — — — — — — — — — — — P   a  g  e 1   9 

,

 S  i   m  p l   i   f   i    e  d   O v  e r  v i    e w  o f    a  G  a  s T   u r   b  i   n  e P   o w  e r  P  l    a n  t    , i    t    s M  a  j    o r   C   o m  p  o n  e n  t    s  a n  d   S   y  s  t    e m  s TEG Fuel Chemical Heat  Air  UG UG DI Pel Pel n f  Inputs: air  fuel Generator block Electrical Generator  breaker  Voltage regulator  (UNITROL) * Output: exhaust gas (heat) Turbine Combustion chamber  Compressor        C     o      u      p       l       i     n     g

Generator  Generator step-uptransformer  Rotor field

Stator  Rotor 

* Trade names for ABB equipment High voltage bushings Output: electric energy Output: mechanical energy Exciter: brushless or static Grid breaker  Synchronizer  (SYNCHROTACT)* Gas turbine electronic

controller  - Sequencing - Control/ regulation - Protection ( EGATROL) * Generator protection ( GSX/ REG)

Turbine fuel valves trip and control

Neutral point Electrical energy to consumers U / f G G nTurbine U / f N N

Gas turbine block

Mechanical

: Main electric energy supply : Feedback signal : Actuation signal : Information exchange signal P : Electric power  n : Rotational speed T : Exhaust gas temperature f : Frequency Differential current U : Generator voltage U : Net voltage f : Generator frequency f : Net frequency MV : Medium voltage el G N G N DI : MV MV DC CSXA400183.cdr 

(20)

 C   om  b i   n  e  d   C   y   c l    e  C   C  P  P   O v  e r  v i    e w P   ow  er  l    an  t    s   (    S i   n  gl    e- an  d  M  ul    t  i  - S  h   af    t   — — — — — — — — — — P   ow  er  l    an  t   r   ai  ni   n  g  C   en  t    er  — — — — — — — — — — — — — — — — P   a  g  e 2   0 

,

 S  i   m  p l   i   f   i    e  d   O v  e r  v i    e w  o f    S   t    e  a m T   u r   b  i   n  e P   o w  e r  P  l    a n  t    , i    t    s M  a  j    o r   C   o m  p  o n  e n  t    s  a n  d   S   y  s  t    e m  s CSXA400184.CDR Rotor  Generator  breaker  Steam Water  Coupling PS TS Pel f G Pel f G UG f N UN UG DI nG Electrical Condensate extraction pump Condenser 

* Trade names for ABB equipment Generator field Generator stator  High voltage bushings Exciter: brushless or static Grid breaker  Neutral point OUTPUT: Electrical energy to consumers Condensate ( Water) Steam and water 

vapor  Generator  step- up transformer  Boiler  Fuel  Air  Deaerator and feed water  storage tank Boiler feedwater  pump Make- up water  Cooling medium in Cooling medium out Exhaust gas Steam turbine Main steam

Turbine steam valves trip and control

Steam turbine electronic controller  - Control - Regulation - Protection ( TURBOTROL) * Generator  protection ( GSX/ REG) * Voltage regulator  ( UNITROL) * Synchronyzer  ( SYNCHROTACT) *

Turbine- generator set sequencer  ( TURBOMAT) *

Inputs : Water 

: Main electrical energy supply : Feedback signal : Actuation Signal : Information exchange signal P : Electrical power  n : Rotational speed of generator  f : Frequency of generator  U : Voltage of generator  f : Frequency of net or grid U : Voltage of net or grid

Differential current P : Steam pessure T : Steam temperature el G G G N N S S DI :

(21)

 C   om  b i   n  e  d   C   y   c l    e  C   C  P  P   O v  e r  v i    e w P   ow  er  l    an  t    s   (    S i   n  gl    e- an  d  M  ul    t  i  - S  h   af    t   — — — — — — — — — — P   ow  er  l    an  t   r   ai  ni   n  g  C   en  t    er  — — — — — — — — — — — — — — — — P   a  g  e 2  1 

,

:   C   o m  b  i   n  e  d   C   y  c l    e P   o w  e r  P  l    a n  t   P  r   o  c  e  s  s  O v  e r  v i    e w  (   M  u l    t   i   - S  h   a f    t    )   CSXA400185.cdr  HRSB G G Condensate extraction pump Main condenser  Cooling Medium HP steam turbine LP steam turbine IP steam turbine feedwater  storage tank High pressure feedwater pump Low / intermediate pressure feedwater pump Steam pressure reducing valve Combustion chamber  Generator  Gas turbine Natural gas Fuel gas preheater  Low pressure economizer  Intermediate pressure economizer  Intermediate pressure evaporator  Intermediate pressure superheater  High pressure evaporator  High pressure superheater and intermediate pressure reheater  LP steam drum

Low pressure water  circulation pump

Intermediate pressure water  circulation pump

High pressure water  circulation pump Low pressure deaeration steam control valve Feedwater  control valve Heat recovery steam boiler  High pressure economizer  Generator  IP steam drum HP steam drum Compressor  Low pressure evaporator 

(22)

 C   om  b i   n  e  d   C   y   c l    e  C   C  P  P   O v  e r  v i    e w P   ow  er  l    an  t    s   (    S i   n  gl    e- an  d  M  ul    t  i  - S  h   af    t   — — — — — — — — — — P   ow  er  l    an  t   r   ai  ni   n  g  C   en  t    er  — — — — — — — — — — — — — — — — P   a  g  e 2  2 

,

:   C   o m  b  i   n  e  d   C   y  c l    e P   o w  e r  P  l    a n  t   P  r   o  c  e  s  s  O v  e r  v i    e w  (    S  i   n  g l    e - S  h   a f    t    )   G Natural gas Fuel gas preheater  Condensate extraction pump Main condenser  Cooling Medium HP steam turbine LP steam turbine IP steam turbine Deaerator  feedwater  storage tank High pressure feedwater pump Low / intermediate pressure feedwater pump Steam pressure reducing valve HRSB Combustion chamber  Generator 

Self shifting and synchronicing clutch Gas turbine Low pressure economizer  Low pressure evaporator  Intermediate pressure economizer  Intermediate pressure evaporator  Intermediate pressure superheater  High pressure evaporator  High pressure superheater and intermediate pressure reheater  LP steam drum

Low pressure water  circulation pump

Intermediate pressure water  circulation pump

High pressure water  circulation pump Low pressure deaeration steam control valve Feedwater  control valve Heat recovery steam boiler  High pressure economizer  IP steam drum HP steam drum Compressor  CSXA400186.CDR

(23)

Figure 3.3: Combined Cycle Plant for CHE Supply and

Multi-Shaft Arrangement

Natural gas (fuel oil) Flue gases  Air  inlet 100°C Heat-recovery steam boiler  (HRSB) 500°C Electricity

(24)

 C   om  b i   n  e  d   C   y   c l    e  C   C  P  P   O v  e r  v i    e w P   ow  er  l    an  t    s   (    S i   n  gl    e- an  d  M  ul    t  i  - S  h   af    t   — — — — — — — — — — P   ow  er  l    an  t   r   ai  ni   n  g  C   en  t    er  — — — — — — — — — — — — — — — — P   a  g  e 2  4 

,

:   C   o m  b  i   n  e  d   C   y  c l    e P  l    a n  t   f    o r   C  H E   S   u  p  p l    y  a n  d   S  i   n  g l    e - S  h   a f    t   A r  r   a n  g  e m  e n  t   CSXA400188.cdr  Heat recovery steam boiler  (HRSB) Flue gases  Air  inlet Natural gas (fuel oil) Gas turbine Generator  SSS clutch Electricity Main condenser  CW circulating pump Cooling water (CW) Heating condenser  Condensate extraction pumps Circulating pump

District heating system Steam Steam turbine Deaerator  feedwater  storage tank Boiler  feedwater pump SSS: self synchronyzing and shifting Condensate

(25)

 C   om  b i   n  e  d   C   y   c l    e  C   C  P  P   O v  e r  v i    e w P   ow  er  l    an  t    s   (    S i   n  gl    e- an  d  M  ul    t  i  - S  h   af    t   — — — — — — — — — — P   ow  er  l    an  t   r   ai  ni   n  g  C   en  t    er  — — — — — — — — — — — — — — — — P   a  g  e 2   5 

,

:   C  H E   S   u  p  p l    y P  l    a n  t   CSXA400189.CDR Condensate Heat consumer  Heat recovery steam boiler  (HRSB) Flue gases  Air  inlet Natural gas (fuel oil) Gas turbine Generator  Electricity CW circulating pump Cooling water (CW) Condensate extraction pumps Circulating pump

District heating system Deaerator  feedwater  storage tank Boiler  feedwater pump SSS: self synchronyzing and shifting CHE: combined heat and electricity

(26)

 C   om  b i   n  e  d   C   y   c l    e  C   C  P  P   O v  e r  v i    e w P   ow  er  l    an  t    s   (    S i   n  gl    e- an  d  M  ul    t  i  - S  h   af    t   — — — — — — — — — — P   ow  er  l    an  t   r   ai  ni   n  g  C   en  t    er  — — — — — — — — — — — — — — — — P   a  g  e 2   6 

,

B  a  s i    c  S   c h   e m  e  o f    t   h   e  C   o n  t   r   o l    o f    a  C   o m  b  i   n  e  d   C   y  c l    e P   o w  e r  P  l    a n  t   CSXA400190.cdr  1 : Air compressor  2 : Combustion chamber  3 : Gas turbine 4 : Generator 

5 : Exhaust gas flap or by- pass 6 : Heat recovery steam boiler  7 : Steam turbine

8 : Condenser 

9 : Condensate extraction pump 10: Deaerator and feedwater storage tank 11: Boiler feedwater pump

12: Supplementary firing MMI: Man machine interface

: Information exchange signal : Actuation signal : Feedback signal BOP: Balance of plant Remark:

For simplicity reasons only one line is represented for: sented for: - Information exchange - Commands - Feedback informations MMI

BOP CONTROLLER MMI

EGATROL (open-and closed-loop control) TURBOMAT (open-loop control) BOILERMAT (open-and closed-loop control) MISCELANEOUS (water steam cycle) UNITMASTER

TURBOTROL (closed-loop control)

BOP equipment like: -Main cooling water  -Main condenser tube cleaning

system -Cooling tower  -Closed cooling water system -Rain water system -Desalination plant -Water treatment plant -Waste water system -Fael gas supply system -Fuel oil supply system

4 1 3 2 4 5 6 10 11 8 9 7 12

(27)

 C   om  b i   n  e  d   C   y   c l    e  C   C  P  P   O v  e r  v i    e w P   ow  er  l    an  t    s   (    S i   n  gl    e- an  d  M  ul    t  i  - S  h   af    t   — — — — — — — — — — P   ow  er  l    an  t   r   ai  ni   n  g  C   en  t    er  — — — — — — — — — — — — — — — — P   a  g  e 2  7 

,

 S  i   m  p l   i   f   i    e  d  W  a  t    e r   S   t    e  a m  C   y  c l    e CSXA400269.CDR ICS: DPR: SSPT: KA24-1 ICS / DPR / SSPT

Innovative cycle solution Dual pressure reheat Single shaft power train

References

Related documents

This figure shows that the mass flow rate is the largest factor that determines the cooling efficiency and that the ambient relative humidity has a large impact on the

When you apply for any of our policies, or make a claim under one of those policies, if we need sensitive information we collect it in accordance with the National

Anadolu University College of Open Education has initiated a new ePortfolio system in 2008 for its Early Childhood Education Teacher Preparation Program with over 12,000

It refered to the model of probation service that used to be based on community probation officers who did welfare work.. The aim of this decision was to change

Interviews with eight people involved in China’s art world, including art collectors, artists, and art dealers, and one year of field research at the Artlagoon Gallery in Richmond,

Integrated Planning of Service Engineers and Spare Parts Inventory in Maintenance Logistics with spare parts emergency shipment. Integrated service engineers and spare parts

The high frequency of this strategy (along with explicit benediction strategy, discussed below) is likely due to the fact that it is a routinized expression in Saudi Arabic and

This work extends the already proposed method considering surface normal information during the learning process and performing an extensive evaluation on noisy point clouds