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Coal Fired Steam Plants

Lee Layton, P.E.


Course Outline

The first section of this course is a detailed overview of the coal industry, including the types of coal found in the US, the locations of coal reserves, and the heat content of the various types of coal.  The next section takes step by step look at how coal is converted into electrical energy and discusses several of the major components found in a coal-fired steam plant.  The final section discusses the environmental aspects of coal-fired electricity production.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

After taking this course you will:

Intended Audience

This course is suitable for anyone who wants to know more about how electric energy is generated and specifically how coal-fired power plants operate.

Benefit to Attendees

This course will give you a good understanding of the coal market and how coal is used to generate electricity as well as a few of the environmental concerns with coal-fired generation.

Course Introduction

Coal fired power plants are an established source of electricity that provides vast quantities of inexpensive, reliable power.  Generation from coal burning produces about 51% of the electricity generated in the U.S.  In addition, known coal reserves are expected to last for centuries at the current rates of usage.  

Coal is by far the most prevalent fuel source with nuclear fuel a distance second, followed closely by natural gas.  It is expected that nuclear and natural gas will eventually surpass coal as the fuel of choice in the next 30 years.

Coal power is a rather simple process. In most coal fired power plants, chunks of coal are crushed into fine powder and are fed into a combustion unit where it is burned. Heat from the burning coal is used to generate steam that is used to spin one or more turbines to generate electricity. 

Coal has played a major role in electrical production since the first power plants that were built in the United States in the 1880's. The earliest power plants used hand fed coal to heat a boiler and produce steam. This steam was used in reciprocating steam engines which turned generators to produce electricity.  In 1884, the more efficient high speed steam turbine was developed which replaced the use of steam engines to generate electricity.  In the 1920s, the pulverized coal firing was developed. This process brought advantages that included a higher combustion temperature, improved thermal efficiency and a lower requirement for excess air for combustion.  In the 1940s, the cyclone furnace was developed. This new technology allowed the combustion of poorer grade of coal with less ash production and greater overall efficiency. 

Coal is pulverized into a fine powder stems because, if the coal is made fine enough, it will burn almost as easily and efficiently as a gas.  The coal is crushed between balls or cylindrical rollers that move between two tracks or "races." The raw coal is then fed into the pulverizer along with air heated from the boiler.  As the coal gets crushed by the rolling action, the hot air dries it and blows the usable fine coal powder out to be used as fuel. The powdered coal from the pulverizer is directly blown to a burner in the boiler. The burner mixes the powdered coal in the air suspension with additional pre-heated combustion air and forces it out of a nozzle.  Under operating conditions, there is enough heat in the combustion zone to ignite all the incoming fuel. 

 Coal-fired technology has improved the heat rates of coal plants from over 138,000 BTU/kWh in the 1880’s to less than 10,000 BTU/kWh today.

The course starts with an overview of the coal industry followed by a detailed explanation of the components of a coal-fired steam plant and we will conclude with a look at the environmental issues associated with a coal-fired steam plant.

Course Content

This course content is in the following PDF document:

Coal Fired Steam Plants

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Course Summary

Coal-fired steam plants are expected to be a cornerstone of electric power generation through at least 2050 and known coal reserves may last for centuries.

Efficiencies in coal-fired power plant operation as well as improved environmental controls will help to keep coal a viable fuel source.  If the promise of carbon sequestration comes to pass, then coal-fired steam plants may remain as one of the lowest cost generation sources for several hundred years.

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.