صفحتنا علي الفيس بوك صفحتنا علي تويتر صفحتنا علي يوتيوب السيـرة الذاتيـة قالــوا عنـــا مقـالاتــي منيـر في الصحف القومية المشهد السياسي مكتبة الفيديو مكتبة الصـور الأتصال بنــا الصفحة الرئيسية
Monir Salah Eldin
  .: مقالاتي | innocent Coal :.
     
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innocent Coal  
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innocent Coal ..
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  كتب : منير صلاح الدين :  
 
  نشر بتاريخ : 03-04-2014
innocent Coal
 
By:
Dr. Eng.  Maher Aziz Bedrous
Energy, Environment and Climate Change Expert
<maher_aziz49@yahoo.com>
 
Recently, false information about using Coal in generating electricity and energy raises controversy in media. This information is very old. It’s since more than many 10s of years ago before industry and technologies of protecting the environment from coal's environmental impacts have been developed.
Due to the spread of false information about using coal as a fuel(unfortunately have been issued by professors who are supposed to have latest knowledge about environmental protection) and due to the absolute neglect of Clean Coal Technology all over the world, it becomes necessary to reveal the correct information about using coal in generating electricity and energy. Also, to highlight the extent to which coal as a fuel becomes a serious competitor for the cleanest fossil fuel available globally, natural gas, in terms of relative environmental hygiene and protection.
WHY COAL?
We draw attention first to the ever increasing demand of electricity and energy as oil and natural gas supplies decrease over the time and are estimated to run out within the next twenty years (unless new unexpected discoveries are achieved). Because of the higher prices of renewables, particularly solar technology to more than eight times the prices of fossil fuels (till commercial break and wide spread of this technology take place leading to lower prices), it becomes necessary to diversify fuel mix for electricity generation in Egypt. This mixture must include hydropower, renewables, oil, gas, nuclear energy and coal.
 
But why coal? this is due to number of critical factors. Most importantly, coal global stocks are enough for only two hundred years, while it’s estimated that oil and gas stocks are enough for forty to sixty years only. That’s why it is plentiful and relatively cheap in the global market. It is also distributed evenly in most parts of the earth unlike oil and gas, which are heavily concentrated in specific countries that control trading and pricing.
Countries having largest stocks, production and export of coal include the United States, Russia, China, India, Indonesia, Australia, Germany, Canada, Colombia, Ukraine, Poland, Kazakhstan and South Africa. Some of these countries have strong relationship with Egypt and can provide it with vast supplies of needed coal at very competitive prices(1, 2, 3).
Coal was also used to provide vast supplies of energy regularly all over the world since 1850. Its global production (growing at a rate of 3% per year)was about 8 billion tons in 2012 compared to around 4.5 billion tons in 1990. It’s expected to continue increasing because of relying so heavily on coal in producing energy all over the world(1).
Coal provides 30% of the primary energy needs in the world. It also generates 41% of global electricity. Moreover, it’s used in producing 70% of global steel production. Experts estimate that coal will continue supplying the world with about 40% of electrical needs till 2030 and after (2, 3, 4).
Coal is considered to be the major fuel used in generating electricity in countries that gives great attention to environmental protection and their different applications are spread all over the world. For example, the United States, where coal provides43% of total electricity needs, Germany (43%), Australia (69%), India (68 %), Poland (86%), South Africa (94%), China (81%), Japan (27%) and the United Kingdom (30%)(2).
These countries use coal in generating this percentage of total electricity generated under strict environmental standards. That’s why using coal in such countries meets the criteria of clean highly protected environment. Japan, known to apply the most stringent environmental standards in the world, generates - as noted above - 27% of electricity from coal. The United States, where the U.S. Environmental Protection Agency sets strict environmental protection standards, generates - as noted above - 43% of electricity from coal. Does these countries neglect the safety of their environment and the health of their children? (3).
Coal, also, is a cheap reliable source of generating electricity. The price of million watt-hour generated from coal ranges from 28 to 64 U.S. dollars compared to 44 to 69 dollars for gas, 97 to 181 dollars for wind power and 226 to 2031 dollars for photovoltaic solar energy (4, 5, 6).
Coal can be converted to liquid, gas, heat and electricity.  It covers a wide range of clean uses according to the latest available technology in the world(4).
ENVIRONMENTAL EXCELLENCE OF COAL-FUELED POWER PLANTS
Coal-fueled electricity generation(and any other fossil fuel such as oil and gas) results in three main pollutants that must be controlled.They are: total suspended particulates (TSP) (particulate matters), sulfur oxides, and nitrogen oxides. Particulate Matters attracted attention at the beginning because it can be seen easily, and due to the direct harmful effect on humans, while attraction to sulfur oxides had arisen from the potential harmful effects on health and plants. Attention to nitrogen oxides also had arisen as a result of contributing in chemical reactions which lead to the formation of photochemical fog in the air. These harmful emissions have attracted the attention of technology producer still they invented the advanced environmental control equipment(8).
As for controlling the Total Suspended Particulates, it is associated with the removal of these particulates from the flow of exhaust gases (flue gases) emitted from power plants.
Removal methods include mechanical cyclone collectors (or cyclone separator), electrostatic precipitators and bughouses. These methods are used in extracting dust and particles of flue gases emitted from power stations with working efficiency exceeding 99.6%(9, 10).
Emissions of sulfur oxides (SOx) can be controlled by one or more of the following methods:
·  Using low sulfur content fuel.
·  Using methods of extracting sulfur from fuel.
·  Using Desulfurization systems of flue gases.
Desulfurization of flue gases began in England in 1935 using old methodstill the sixties of the last century. Later on, desulfurization technologyhas beendevelopedby both the United States and Japan. More than 50 desulfurization processes of flue gases are applied recently; differing in chemical reagent and final product with working efficiency of more than 90% (11).
It should be noted that to meet efficiently the most stringent standards of protecting the environment from pollution, alternatives of integrated systems of particulate matters precipitators and SO2 scrubbers are currently available in the international market so that one can choose from to achieve high quality ambient atmosphere (8).
As for disposing the scrubber wastes, lots of final products are salable in commercial market, while others are of no value except for landfilling. That’s why it’s necessary to take into account local markets, applied regulations of disposing wastes (environmental standards) and available lands for final disposal of solid wastes (which can be utilized in protecting beaches from the overflow of Mediterranean Sea in northern shorelines of Egypt) before starting desulfurization (8, 9, 10).
Criteria for protecting air from Nitrogen Oxides (NOx), perhaps more than the rest of other pollutants, are very strict.Therefore, modifications have been introduced to boilers’ designs to reduce Nitrogen Oxides by:
·        Controlling flame temperature.
·        Low percentage of excess air.
·        Staged combustion.
·        Use of excess combustion air.
·        Tangential firing.
·        Recirculation of flue gases through combustion stages(11).
Although these methods are effective, sufficient and appropriate for reducing Nitrogen Oxides in many countries, great efforts have been madeto reduce emissions of Nitrogen Oxides within permissible limits. Proceduresusually require special treatment methods of gases emitted from the boiler. Many of these methods are applied especially in Japan, where both dry and wet systems are applied to flue gases from units operating by oil and gas and applied later on to coal units (8, 9).
Generally, main methods of Nitrogen Oxides dry reduction include the following:
·        Catalytic decomposition.
·        Selective catalytic reduction.
·        Non-selective catalytic reduction
·        Absorption.
Other methods are developed and tested in pilot plants or during commercial application to get rid of Nitrogen Oxides totally.Perhaps the most important of which is called Thermal Exxon Process to remove Nitrogen Oxides, Hitachi Process, and Mitsubishi Process for Selective Catalytic Reductionin heavy Industries (10, 11).
In fact, air pollution control is not linked to the amount of pollutants only, but rather it’s also linked to the ability of the atmosphere to absorb pollutants without any adverse effects. Modeling studies provide valuable assistance to predict the dispersion paths of combustion plumes emerging from the stacks, and thus keep the concentrations of suspended particulates and flue gas emissions at much lower levels compared to levels specified by air quality standards(9, 10).
Due to dispersion of emissions generated out of boilers, stack heights range from 800 up to1,200 feet. This length can be increased, in fact, by velocity of gas flow that ranges from 75 up to100 ft/ sec. As a result of these factors and due to buoyancy of hot exhaust gases, effective length of stack is obtained. That is about twice and half the physical length of the stack (8, 9).
To find out the removal efficiency of these three major pollutants, an electrical power plant with a capacity of 600 MW (i.e., containing only two units of four of the power plant in Shubra Al Kheimah, north of Cairo) burns coal as a fuel resulting in about 21.5 thousand kilograms per hour of total suspended particulates emitted in flue gases without using pollution control equipment. But, when these equipment are used, more than 21.4 thousand kilograms are captured away from air. About 2.5 thousand kilograms per hour of Sulfur Oxides produced and can be reduced to about 200 kg / h by control devices. Moreover, about 2.2 thousand kilograms per hour of Nitrogen Oxides produced and can be reduced to less than 150 kg/hour by NOx removal technology (10, 11).
Sulfur Oxides emissions is 100 milligrams per cubic meter in Tureva power plant that burns coal as a fuel in Italy (with a capacity of 600MW),whilethe Egyptian law-and the World Bank as well-state that health and environmental protection limits are up to 1300mg per cubic meter, and 100 milligrams per cubic meter for Nitrogen Oxides emissions, the Egyptian law and the World Bank set up the upper limit for health and environmental protection by about 500 milligrams per cubic meter. This is an example of a power plant using coal as a fuel and competes cleanest power plant using natural gas(8, 10).
As for greenhouse gases (GHGs), a power plant using coal with operating efficiency of 30% produces about 1,000 grams of Carbon Dioxide per kilowatt-hour, but it falls down to about 800 grams per kilowatt-hour if efficiency is increased to 38%, and to about 600 grams per kilowatt-hour (i.e., equivalent to natural gas) at efficiency of 50%, a technology currently available in the global market(8, 10).
Vast resources of oil shale in Egypt – treated as coal – are suitable to generate sufficient amounts of electricity lasting for more than hundreds of years. These resources are needed strongly due to continued depletion of oil and natural gas. Egypt will import coal to be used in generating power to prolong the use of these resources. Why do we refuse using coal and oil shale in generating electricity because of false beliefs regarding environmental pollution? These false beliefs are grown up by blockhead people having old information about coal since more than many 10s of years ago, and offering misleading advice to the authorities responsible for protecting the environment.
The author served as a First Deputy for Energy and Environment (MoEE), a member of Egyptian Delegation to the United Nations Framework Convention on Climate Change negotiations, a member of the National  Specialized Councils, a member of the Board of Mid Delta Electricity Production Company, and an international Consultant for Environmental & Social Impact Assessment (ESIA) of projects.
REFERENCES:
(1)         World Coal Association (2012): "Coal Matters- 3/Coal and Electricity Generation".
(2)         World Coal Association (2012): "Coal Facts 2013"; London.
(3)         World Coal Institute (2012): "The Coal Resources - A Comprehensive Overview of Coal".   
(4)         OECD/International Energy Agency (2011): "Energy for All-Financing Access for the Poor".
(5)         OECD/International Energy Agency (2013): "Monthly Electricity Statistics", August 2013.
(6)         World Energy Council (2013): "World Energy Resources, 2013 Survey".
(7)         Tonella (2012): "International Leadership and Protecting the World's Energy Resources".
(8)         Combustion Engineering Textbook: Thermal Power Plant Technology.
(9)         Babcok @ Wilcoks Textbook: Thermal Power Plants.
(10)      Power Plants Planning, Design and Operation (18 Volumes).
(11)      Dr. El-Abiyab: "Power Plant Technology".    
  
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