Design And Construction Of A Coal-Fired Power Generator

Coal-fire power generator is a power plant in which the prime mover is steam driven, and the steam is been heated with coal. Water is heated (with coal), turns into steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the steam is condensed in a condenser and recycled to where it was heated; this is known as a Rankine cycle.

Commercial electric utility power stations are usually constructed on a large scale and designed for continuous operation. Coal-fire power generator typically uses three-phase electrical generators to produce alternating current (AC) electric power at a frequency of 50 Hz or 60 Hz. Large companies or institutions may have their own power plants to supply heating or electricity to their facilities, especially if steam is created anyway for other purposes.

CHAPTER ONE

1.0                                                        INTRODUCTION

Fossil fuels are indeed the top fuels used all over the world for generating power and electricity. Among the fossil fuels, coal is the most widely used fuel in power plants. Coal fired power plants boiler use different kinds of machinery that convert heat energy produced from combustion into mechanical energy.
Coal, gas, and oil are the fossil fuels responsible for most of the world’s electricity and energy demands. Coal, which is readily available in most of the developing and developed world, has been used as a major source of fuel even in ancient human civilizations. It also found its use in historic steam engines at the dawn of the industrial revolution.

Coal-fired power stations are burning an increasingly varied range of fuels and fuel blends, including sub-bituminous and lower volatile coals and biomass of varying composition and combustion properties, under tight economic and environmental constraints. Since existing coal-fired plants are not designed to burn such a diverse range of fuels, the power generation industry has to overcome a range of technological problems such as poor combustion efficiency, increased pollutant emissions and other operational issues such as poor flame stability and slagging and fouling. The recent trend in operating power plants in variable load in response to changes in electricity demand has exacerbated the aforesaid problems. To meet the increasingly stringent standards on combustion efficiency, pollutant emissions and renewables obligations and to maintain fuel flexibility, advanced monitoring and control techniques have become highly desirable in the power generation industry.

In electrical power generation solids fuel is supplied from a bunker into a pulverising mill and the pulverised fuel is then pneumatically conveyed towards the furnace by splitting a larger fuel pipe into smaller ones through bifurcations and/or trifurcations. The fuel distribution network feeds a matrix of burners on a wall-fired or a tangentially fired furnace.

1.1                                             OBJECTIVE OF THE PROJECT

Coal-fired electricity generation involves burning thermal coal (either black or brown) that has been pulverised to a fine powder to make it easier to burn. The heat is then used to turn water into steam, which is used to turn a turbine connected to an electrical generator.

However, the main aim of this work is setup a coal-fired generator that can generate alternating voltage at 50hz frequency.

1.2                                              PURPOSE OF THE PROJECT

The purpose of this work is to setup a power generator that can be controlled to supply power using coal to heat the water that rotates the turbine blade.

1.3                                         SIGNIFICANCE OF THE PROJECT

Today, advances in technology have allowed coal to improve living conditions with its current role in meeting man’s fuel needs. Coal has been used extensively in power generation where better technology is employed to ensure that there is a balance between ecology and economics in producing sustainable and affordable energy. Some of its advantages include reliability, affordability, abundance, known technologies, safety, and efficiency.

1. Reliability. One of the greatest advantages of coal fired power plants boiler is reliability. Coal’s ability to supply power during peak power demand either as base power or as off-peak power is greatly valued as a power plant fuel. It is with this fact that advanced pulverized coal fired power plants are designed to support the grid system in avoiding blackouts.
2. Affordability. Energy produced from coal fired plants is cheaper and more affordable than other energy sources. Since coal is abundant, it is definitely cheap to produce power using this fuel. Moreover, it is not expensive to extract and mine from coal deposits. Consequently, its price remains low compared to other fuel and energy sources.
3. Abundance. There are approximately over 300 years of economic coal deposits still accessible. With this great amount of coal available for use, coal fired plants can be continuously fueled in many years to come.
   4. Known technologies. The production and use of coal as a fuel are well understood, and the technology required in producing it is constantly advancing. Moreover, coal-mining techniques are continuously enhanced to ensure that there is a constant supply of coal for the production of power and energy.
   5. Safety. Generally, coal fired plants are considered safer than nuclear power plants. A coal power plant’s failure is certainly not likely to cause catastrophic events such as a nuclear meltdown would. Additionally, the welfare and productivity of coal industry employees has greatly improved over the years. In fact, injuries, time lost, and fatalities have decreased significantly in the past years.

1.4                                                 SCOPE OF THE PROJECT

Steam coal, also known as thermal coal, is used in power stations to generate electricity. Coal is first milled to a fine powder, which increases the surface area and allows it to burn more quickly. In these pulverized coal combustion (PCC) systems, the powdered coal is blown into the combustion chamber of a boiler where it is burnt at high temperature. The hot gases and heat energy produced converts water – in tubes lining the boiler – into steam.

The high pressure steam is passed into a turbine containing thousands of propeller-like blades. The steam pushes these blades causing the turbine shaft to rotate at high speed. A generator is mounted at one end of the turbine shaft and consists of carefully wound wire coils. Electricity is generated when these are rapidly rotated in a strong magnetic field. After passing through the turbine, the steam is condensed and returned to the boiler to be heated once again.

The electricity generated is transformed into the higher voltages (up to 400,000 volts) used for economic, efficient transmission via power line grids.

1.5                                           LIMITATION OF THE PROJECT

Coal plants, like most other steam-producing electricity-generating plants, typically withdraw and consume water from nearby water bodies, such as lakes, rivers, or oceans, to create steam for turning their turbines.

A typical coal plant with a once-through cooling system withdraws between 70 and 180 billion gallons of water per year and consumes 0.36 to 1.1 billion gallons of that water. A typical coal plant with a wet-recirculating cooling system withdraws only a fraction as much as a once-through-cooled plant, but consumes 1.7 to 4.0 billion gallons per year, while a typical coal plant with a dry-cooled system consumes much less.

When water is drawn into a coal power plant, millions of fish eggs, fish larvae, and juvenile fish may also come along with it. In addition, millions of adult fish may become trapped against the intake structures. Many of these fish are injured or die in the process.

Burning coal pollutes our environment with toxins, produces a warming emissions, and accounts for a whopping 80 percent of all carbon emissions produced by power generation nationwide. It’s time to reduce our dependence on this polluting energy source.

1.6                                              PROBLEM OF THE PROJECT

1. Greenhouse gas emissions. It cannot be denied that coal leaves behind harmful byproducts upon combustion. These byproducts cause a lot of pollution and contribute to global warming. The increased carbon emissions brought about by coal fired plants has led to further global warming which results in climate changes.
2. Mining destruction. Mining of coal not only results in the destruction of habitat and scenery, but it also displaces humans as well. In many countries where coal is actively mined, many people are displaced in huge numbers due to the pitting of the earth brought about by underground mining. Places near coal mines are unsafe for human habitation as the land could cave in at anytime.
3. Generation of millions of tons of waste. Millions of tons of waste products which can no longer be reused are generated from coal fired plants. Aside from the fact that these waste products contribute to waste disposal problems, these also contain harmful substances.

Coal-fired power stations are relatively expensive to build since their construction involves both large quantities of expensive materials, such as iron and steel, and large volumes of labor. While some parts of a coal-fired power plant such as its steam turbines can be assembled in a factory and then delivered to the site, much of the assembly of the boiler and flue-gas cleaning systems must take place at the site itself. As a consequence, the cost of a coal-fired power plant will be vulnerable to changing commodity costs and generally increasing labor costs.

1.7                                        PROJECT WORK ORGANISATION

The various stages involved in the development of this project have been properly put into five chapters to enhance comprehensive and concise reading. In this project thesis, the project is organized sequentially as follows:

Chapter one of this works is on the introduction to coal fired power generator. In this chapter, the background, significance, objective limitation and problem of coal fired power generator were discussed.

Chapter two is on literature review of coal fired power generator. In this chapter, all the literature pertaining to this work was reviewed.

Chapter three is on design methodology. In this chapter all the method involved during the design and construction were discussed.

Chapter four is on testing analysis. All testing that result accurate functionality was analyzed.

Chapter five is on conclusion, recommendation and references.