PPE Assignment 1

7/30/2019 PPE Assignment 1

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Process Plant Engineering 322

Assignment 1

P&ID and Process Evaluation

Craig Underwood 15495073


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Table of Contents

Conventional Power Plant .......................................................................................................... 3Process Summary ........................................................................................................................................................................... 3

Analysis and Evaluation of the Conventional Power Plant Process .................... .................... ..................... ............. 3

Reasoning for the Inclusion/Placement of Control and Instrumentation Parts ........................ .................... ...... 4

Integrated Coal Gasification Combined Cycle System .................................................................. 5Process Summary ........................................................................................................................................................................... 5

Analysis and Evaluation of the IGCC Process ...................................................................................................................... 5

Reasoning for the Inclusion/Placement of Control and Instrumentation Parts ........................ .................... ...... 6

References ................................................................................................................................. 7


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Conventional Power Plant

Process Summary

A conventional coal-fired power plant (also known as a pulverised coal power plant) produces electricity by

the burning of coal and air in a steam generator, where it heats water to produce high pressure and high

temperature steam. The steam flows through a series of steam turbines, which spin an electrical generator

to produce electricity. The exhaust steam from the turbines is cooled and condensed back into water and

either disposed of or returned to the steam generator to start the process over (Citizendium 2013).

Pulverised coal power plants are broken down into three categories: subcritical, supercritical and ultra-

supercritical. The primary difference between the three types of pulverised coal boilers is the operating

temperatures and pressures. Subcritical plants operate below the critical point of water (647.096K and

22.064MPa (IAPWS 2013)), whereas supercritical and ultra-supercritical plants operate above the criticalpoint. As the pressure and temperature increase, so does the operating efficiency. Subcritical plants

operate at 33-37%, supercriticals at 38-40% and ultra-supercriticals in the 41-45% range (Sourcewatch

2012).

Analysis and Evaluation of the Conventional Power Plant Process

This point form analysis addresses the main advantages and disadvantages of conventional power plants. It

may be treated as a preliminary evaluation of information with a view to perform a detailed technical and

economic feasibility study for power generation via this method.

Below are a number ofadvantages associated with using conventional coal-fired power plants:

1. Conventional pulverised-coal combustion is the most widely used technology in coal-fired powergeneration and is based on decades of experience (CAER 2009).

2. Simply raising the steam pressure and temperature can increase the thermal efficiency. This hasthe added benefit of lowering emissions such as carbon dioxide (CAER 2009).

3.

Conventional power plants provide reliable, cost-effective power on a continued basis, load cyclingcapability, fast daily startups and fast, sustained load response as well as load rejection capability

(CAER 2009).

4. As there are not a large number of process units involved, the capital cost of conventional powerplants is significantly less than IGCC systems (EPA 2006).

5. Developments in materials science continually produce new metal alloys that allow power stationsto use higher pressure and higher temperature in the boiler and steam turbines above the critical

point for steam (ACALET 2012).

6. The next generation of advanced ultra-supercritical power stations is currently being development,which will further improve efficiency (ACALET 2012).


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However, there are some disadvantages associated with using conventional coal-fired power plants:

1. Conventional pulverised-coal power plants remain a relatively simple technology, converting a littlemore than one-third of the fuels energy into useful electricity (WRI 2008)

2. In 2008, the European Environment Agency (EEA) documented emissions from conventional powerplants. The results showed high levels of CO2, SO2, NOX, CO, organic compounds and particulate

matter being emitted into the atmosphere.

3. Coal-fired power plants are responsible for emitting 66% of sulfur oxides, 40% of carbon dioxide,33% of mercury and 22% of nitrogen oxides into the atmosphere (Energy Justice 2007)

4. Conventional coal plants typically withdraw process water from nearby water bodies, such as lakes,rivers or oceans. A typical once-through coal plant consumes 0.36 to 1.1 billion gallons of this water

each year (UCS 2012).

Reasoning for the Inclusion/Placement of Control and Instrumentation Parts

In order to satisfy operational objectives for the conventional power plant process, a number of control and

instrumentation parts have been included in the P&ID.


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Integrated Coal Gasification Combined Cycle System

Process Summary

In an integrated coal gasification combined cycle (IGCC) system, coal is heated and partially oxidised with

oxygen and steam and the resulting syngas (primarily hydrogen and carbon monoxide) is cooled, cleaned

and fired in a gas turbine-generator. Oxygen for the gasifier is produced in an air separation plant. The gas

turbine exhaust goes to a heat recovery steam generator (HRSG), producing steam that is sent to a steam

turbine-generator. Power is produced from both turbine-generators (EPA 2006).

There are many variations on the basic IGCC scheme, especially in the degree of process integration. Three

major types of gasification systems are used today: moving-bed, fluidized-bed and entrained-flow.

According to the EPA in 2006, all of the currently operating IGCC plants utilize entrained-flow gasifier

designs. In entrained-flow gasifiers, finely pulverized coal particles concurrently react with steam andoxygen with very short residence time. These gasifiers operate at high temperature where the coal ash

becomes a liquid slag (EPA 2006).

Analysis and Evaluation of the IGCC Process

This point form analysis addresses the main advantages and disadvantages of IGCC systems for power

generation. It may serve as a preliminary evaluation of information with a view to perform a detailed

technical and economic feasibility study for power generation via this method.

Below are a number ofadvantages associated with using IGCC systems for power generation:

1. It is generally accepted that the IGCC system, by removing most pollutants from the syngas prior tocombustion, is capable of meeting more stringent emission standards than conventional

technologies (EPA 2006).

2. IGCC has greater promise to incorporate carbon dioxide capture for sequestration without largecost and energy penalties (EPA 2006).

3.

IGCC can achieve up to 50% thermal efficiency. This is a higher efficiency compared to conventionalcoal power plants meaning there is less coal consumed to produce the same amount of energy

(CCSD 2008).

4. IGCC uses 20-50% less water than conventional power plants (CCSD 2008).5. Nitrous oxide emissions are below 50ppm, which is lower than most conventional plants (CCSD

2008).

6. With carbon capture and storage (CCS), IGCC plants could capture 85-95% of their emissions, whichcould then be injected into deep underground formations (WRI 2008).

7. Increased efficiency improves the economics and therefore promotes the feasibility of installingCCS systems to control IGCC emissions (ACALET 2012).


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However, there are some disadvantages associated with using IGCC systems for power generation:

1. In most cases, IGCC costs are higher and more uncertain than for conventional plants, becauseconventional technology has been demonstrated and researched at many more installations (EPA

2006).

2. Without CCS, IGCC plants are likely to offer, at best, a small reduction in carbon dioxide emissionscompared to traditional coal plants (WRI 2008).

3. In most cases, a back-up gasifying unit is required for reliable operation of IGGC plants. This sparegasifier raises capital cost (WRI 2008).

4. ICGG systems require 33-90% more water when CCS equipment is used (Ekpolitan, 2011).5. The gasification process operates best under steady-state conditions and the load change

conditions associated with utility electricity generation will burden IGCC technology (National Coal

Council 2009)

6. The National Coal Council (2009) indicated that the electricity generating efficiency of IGCC systemsto date do not live up to their earlier projections due to the many engineering and design

compromises that have to be made to achieve acceptable operability and cost.

7. Capital costs for IGCC plants are estimated to be 20-47% higher than conventional coal plants(Energy Justice 2007).

8. Using water to clean the gas creates water contamination problems, with ICGG wastewater onaverage having a pH of 9.8 (Energy Justice 2007).

Reasoning for the Inclusion/Placement of Control and Instrumentation Parts


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References

http://www.fossil.energy.gov/education/energylessons/coal/gen_coal.html

http://en.citizendium.org/wiki/Conventional_coal-fired_power_plant

http://www.epa.gov/oar/caaac/coaltech/2007_01_epaigcc.pdf

http://www.wri.org/publication/content/8125

http://www.ccsd.biz/factsheets/igcc.cfm

http://www.caer.uky.edu/energeia/PDF/vol20_1.pdf

http://www.ekopolitan.com/news/ccs-report-ccs-will-increase-power-plants-water-consumtion-33-90-

could-repr

http://www.wri.org/publication/content/10338

http://www.iapws.org

http://www.sourcewatch.org/index.php/Coal_power_technologies

http://mitei.mit.edu/system/files/beer-emissions.pdf

http://www.newgencoal.com.au/click-here-to-read-how-power-plants-are-reducing-emissions-by-making-

coal-more-efficient.html

http://www.energyjustice.net/files/coal/igcc/factsheet.pdf

http://www.ucsusa.org/clean_energy/coalvswind/c02b.html

European Environment Agency. 2008. Air Pollution From Electricity-Generating Large Combustion Plants.

An assessment of the theoretical emission reduction of SO2 and NOXthrough implementation of BAT

as set in the BREFs. doi: 10.2800/3609.
http://www.fossil.energy.gov/education/energylessons/coal/gen_coal.htmlhttp://www.fossil.energy.gov/education/energylessons/coal/gen_coal.htmlhttp://en.citizendium.org/wiki/Conventional_coal-fired_power_planthttp://en.citizendium.org/wiki/Conventional_coal-fired_power_planthttp://www.epa.gov/oar/caaac/coaltech/2007_01_epaigcc.pdfhttp://www.epa.gov/oar/caaac/coaltech/2007_01_epaigcc.pdfhttp://www.wri.org/publication/content/8125http://www.wri.org/publication/content/8125http://www.ccsd.biz/factsheets/igcc.cfmhttp://www.ccsd.biz/factsheets/igcc.cfmhttp://www.caer.uky.edu/energeia/PDF/vol20_1.pdfhttp://www.caer.uky.edu/energeia/PDF/vol20_1.pdfhttp://www.ekopolitan.com/news/ccs-report-ccs-will-increase-power-plants-water-consumtion-33-90-could-reprhttp://www.ekopolitan.com/news/ccs-report-ccs-will-increase-power-plants-water-consumtion-33-90-could-reprhttp://www.ekopolitan.com/news/ccs-report-ccs-will-increase-power-plants-water-consumtion-33-90-could-reprhttp://www.wri.org/publication/content/10338http://www.wri.org/publication/content/10338http://www.iapws.org/http://www.iapws.org/http://www.sourcewatch.org/index.php/Coal_power_technologieshttp://www.sourcewatch.org/index.php/Coal_power_technologieshttp://mitei.mit.edu/system/files/beer-emissions.pdfhttp://mitei.mit.edu/system/files/beer-emissions.pdfhttp://www.newgencoal.com.au/click-here-to-read-how-power-plants-are-reducing-emissions-by-making-coal-more-efficient.htmlhttp://www.newgencoal.com.au/click-here-to-read-how-power-plants-are-reducing-emissions-by-making-coal-more-efficient.htmlhttp://www.newgencoal.com.au/click-here-to-read-how-power-plants-are-reducing-emissions-by-making-coal-more-efficient.htmlhttp://www.energyjustice.net/files/coal/igcc/factsheet.pdfhttp://www.energyjustice.net/files/coal/igcc/factsheet.pdfhttp://www.ucsusa.org/clean_energy/coalvswind/c02b.htmlhttp://www.ucsusa.org/clean_energy/coalvswind/c02b.htmlhttp://www.ucsusa.org/clean_energy/coalvswind/c02b.htmlhttp://www.energyjustice.net/files/coal/igcc/factsheet.pdfhttp://www.newgencoal.com.au/click-here-to-read-how-power-plants-are-reducing-emissions-by-making-coal-more-efficient.htmlhttp://www.newgencoal.com.au/click-here-to-read-how-power-plants-are-reducing-emissions-by-making-coal-more-efficient.htmlhttp://mitei.mit.edu/system/files/beer-emissions.pdfhttp://www.sourcewatch.org/index.php/Coal_power_technologieshttp://www.iapws.org/http://www.wri.org/publication/content/10338http://www.ekopolitan.com/news/ccs-report-ccs-will-increase-power-plants-water-consumtion-33-90-could-reprhttp://www.ekopolitan.com/news/ccs-report-ccs-will-increase-power-plants-water-consumtion-33-90-could-reprhttp://www.caer.uky.edu/energeia/PDF/vol20_1.pdfhttp://www.ccsd.biz/factsheets/igcc.cfmhttp://www.wri.org/publication/content/8125http://www.epa.gov/oar/caaac/coaltech/2007_01_epaigcc.pdfhttp://en.citizendium.org/wiki/Conventional_coal-fired_power_planthttp://www.fossil.energy.gov/education/energylessons/coal/gen_coal.html

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PPE Assignment 1