Thermal power plants produce air pollution by combusting fuels like coal, gas and oil to generate steam for power production. The major air pollutants released are particulate matter like fly ash, and gases such as sulfur oxides, nitrogen oxides and trace metals. The document discusses the various pollution control technologies used at coal power plants to control particulate matter like electrostatic precipitators and flue gas desulfurization systems like limestone scrubbing to reduce sulfur dioxide emissions. Technologies for lowering nitrogen oxides include combustion modifications, selective catalytic reduction using ammonia and selective non-catalytic reduction. The aim of these control systems is to reduce the health and environmental impacts of air pollution from thermal power generation.
Environmental impact of thermal power plantSiraskarCom
Environmental impact of thermal power plant, Different pollutants from thermal power plants, their effects on human health and vegetation, methods to control pollutants such as particulate matter; oxides of sulphur; oxides of nitrogen, dust handling systems, ESP, scrubbers, water pollution, thermal pollution, noise pollution from TPP and its control
Flue gas desulfurization is commonly known as FGD and is the technology used for removing sulfur dioxide (SO2) from the exhaust combustion flue gases of power plants that burn coal or oil to produce steam for the turbines that drive their electricity generators.
PPT ON THERMAL POWER PLANT (POLLUTION CONTROLLED)HIMANSHU .
!!!!!!!!!!>LINKS FOR THE VIDEOS ARE<!!!!!!!!!!
>>>https://drive.google.com/drive/folders/1cSouvmjSSu7ZSPBq1AA2TYYn87kepoW8?usp=sharing<<<
A generating station which converts heat energy of coal combustion into electrical energy is known as a thermal power station.
IN THIS PPT THERE ARE SOME WAYS OF USING TECHNIQUES TO SOLVE THE PROBLEM OF POLLUTION CAUSED BY THERMAL POWER PLANT
Environmental impact of thermal power plantSiraskarCom
Environmental impact of thermal power plant, Different pollutants from thermal power plants, their effects on human health and vegetation, methods to control pollutants such as particulate matter; oxides of sulphur; oxides of nitrogen, dust handling systems, ESP, scrubbers, water pollution, thermal pollution, noise pollution from TPP and its control
Flue gas desulfurization is commonly known as FGD and is the technology used for removing sulfur dioxide (SO2) from the exhaust combustion flue gases of power plants that burn coal or oil to produce steam for the turbines that drive their electricity generators.
PPT ON THERMAL POWER PLANT (POLLUTION CONTROLLED)HIMANSHU .
!!!!!!!!!!>LINKS FOR THE VIDEOS ARE<!!!!!!!!!!
>>>https://drive.google.com/drive/folders/1cSouvmjSSu7ZSPBq1AA2TYYn87kepoW8?usp=sharing<<<
A generating station which converts heat energy of coal combustion into electrical energy is known as a thermal power station.
IN THIS PPT THERE ARE SOME WAYS OF USING TECHNIQUES TO SOLVE THE PROBLEM OF POLLUTION CAUSED BY THERMAL POWER PLANT
Steam distribution system, utilization and designAzmir Latif Beg
n any steam plant or any process plant effectiveness of steam distribution system is dependent upon the project specific conditions like location and layout of the process plant and its steam consuming equipment like heat exchangers, decorators etc. Steam distribution circuit is one of the major link between the steam production point and the point of end use i.e. process plant. Primary steam generating source are co-generation plant and Steam generators. However it not the source of steam generation but the effective and efficient steam distribution system that decides right quality (pressure and temperature) and quantity of steam to reach to the process through it. Thus designing of steam distribution is to be given due importance along with installation and subsequently maintenance during operation.
Episode 3 : Production of Synthesis Gas by Steam Methane ReformingSAJJAD KHUDHUR ABBAS
Episode 3 : Production of Synthesis Gas by Steam Methane Reforming
History of Synthesis Gas
In 1780, Felice Fontana discovered that combustible gas develops if water vapor is passed over carbon at temperatures over 500 °C. This CO and H2 containing gas was called water gas and mainly used for lighting purposes in the19th century.
As of the beginning of the 20th century, H2/CO-mixtures were used for syntheses of hydrocarbons and then, as a consequence, also called synthesis gas.
Haber and Bosch discovered the synthesis of ammonia from H2 and N2 in 1910 and the first industrial ammonia synthesis plant was commissioned in 1913.
The production of liquid hydrocarbons and oxygenates from syngas conversion over iron catalysts was discovered in 1923 by Fischer and Tropsch.
Much of the syngas conversion processes were being developed in Germany during the first and second world wars at a time when natural resources were becoming scare and alternative routes for hydrogen production, ammonia synthesis, and transportation fuels were a necessity.
In 1943/44, this was applied for large-scale production of artificial fuels from synthesis gas in Germany.
Episode 42 : Gas Solid Separation
The process may be interpreted to mean both degassing of solids and dedusting of the solids.
3 phases may be distinguished in any gas cleaning process, i.e;
transport of particles onto a surface (separation)
collection of separated particles from the separation surface into discharge hoppers (or particle fixation)
disposal of the collected particles from the gas cleaning equipment
All phases are equally important as the failure of any of the phases will result in the failure of the separation process
SAJJAD KHUDHUR ABBAS
Ceo , Founder & Head of SHacademy
Chemical Engineering , Al-Muthanna University, Iraq
Oil & Gas Safety and Health Professional – OSHACADEMY
Trainer of Trainers (TOT) - Canadian Center of Human
Development
Steam distribution system, utilization and designAzmir Latif Beg
n any steam plant or any process plant effectiveness of steam distribution system is dependent upon the project specific conditions like location and layout of the process plant and its steam consuming equipment like heat exchangers, decorators etc. Steam distribution circuit is one of the major link between the steam production point and the point of end use i.e. process plant. Primary steam generating source are co-generation plant and Steam generators. However it not the source of steam generation but the effective and efficient steam distribution system that decides right quality (pressure and temperature) and quantity of steam to reach to the process through it. Thus designing of steam distribution is to be given due importance along with installation and subsequently maintenance during operation.
Episode 3 : Production of Synthesis Gas by Steam Methane ReformingSAJJAD KHUDHUR ABBAS
Episode 3 : Production of Synthesis Gas by Steam Methane Reforming
History of Synthesis Gas
In 1780, Felice Fontana discovered that combustible gas develops if water vapor is passed over carbon at temperatures over 500 °C. This CO and H2 containing gas was called water gas and mainly used for lighting purposes in the19th century.
As of the beginning of the 20th century, H2/CO-mixtures were used for syntheses of hydrocarbons and then, as a consequence, also called synthesis gas.
Haber and Bosch discovered the synthesis of ammonia from H2 and N2 in 1910 and the first industrial ammonia synthesis plant was commissioned in 1913.
The production of liquid hydrocarbons and oxygenates from syngas conversion over iron catalysts was discovered in 1923 by Fischer and Tropsch.
Much of the syngas conversion processes were being developed in Germany during the first and second world wars at a time when natural resources were becoming scare and alternative routes for hydrogen production, ammonia synthesis, and transportation fuels were a necessity.
In 1943/44, this was applied for large-scale production of artificial fuels from synthesis gas in Germany.
Episode 42 : Gas Solid Separation
The process may be interpreted to mean both degassing of solids and dedusting of the solids.
3 phases may be distinguished in any gas cleaning process, i.e;
transport of particles onto a surface (separation)
collection of separated particles from the separation surface into discharge hoppers (or particle fixation)
disposal of the collected particles from the gas cleaning equipment
All phases are equally important as the failure of any of the phases will result in the failure of the separation process
SAJJAD KHUDHUR ABBAS
Ceo , Founder & Head of SHacademy
Chemical Engineering , Al-Muthanna University, Iraq
Oil & Gas Safety and Health Professional – OSHACADEMY
Trainer of Trainers (TOT) - Canadian Center of Human
Development
The slide show was prepared for educating general public on ill effects of Coal based Thermal power plants, and devastation caused by mining.
Literature available through net and other sources have been referred to for the publications.
Data presented, especially on human health, has been substantiated by recent publication “A report by Physicians for Social Responsibility” by Physicians of US, a group which included Nobel Laureates.
Alternate sources of electricity production also indicated
Thermal plant instrumentation and controlShilpa Shukla
Detail working description of each components used in A Thermal or Coal based Plant for generation of electricity. Controlling and automation is described.
Sulfur oxides are produced from the burning of fossil fuels, mainly coal and oil, and the smelting of metal ores that contain sulfur.
Emissions of sulfur oxides cause serious impacts on human health and the environment, both directly and as a result of the way they react with other substances in the air.
Sulfur oxides are main precursors of atmospheric acidification, aerosol generation, and acidic dry and wet deposition.
There are many methods available for controlling the emission of SO2. Such as:
extraction of sulfur from fuel oils.
Sulfur reduction within combustion chamber.
Treating of flue gases.
DRY METHODS:
Mainly in industries dry, elevated temperature removal processes are used as cold plume is not formed and problem of handling large amount of slurry in flue gases is avoided.
But there are technical issues resulting in such method making wet method more applicable in industries.
Adsorption of SO2 by metal oxides to from stable sulphites or sulphates with subsequent regeneration.
-Alkalized Alumina Process
-Manganese Oxide Process
Adsorption on activated carbon followed by regeneration and conversion of concentrated SO2 to sulphuric acid or elemental sulphur.
-The Reinluft Process
ALKALIZED ALUMINA PROCESS:
Also called as Cyclic Adsorption Process.
It was developed by U.S Bureau of Mines.
Adsorbent used : Sodium Aluminate (Na2O.Al2O3)-it is porous form.
This process uses Sodium Aluminate (Na2O.Al2O3) to remove SO2 in fluidized bed at 315°C.
Na2O.Al2O3 + SO2 + ½ O2 → Na2SO4 + Al2SO3
The product of above reaction is then contacted with a reducing gas such as H2 in a regenerator at 680°C to produce H2S.
Na2SO4 + Al2O3 + 4H2 → Na2O.Al2O3 + H2S + 3H2O
Sodium Aluminate is recycled back and H2S is sent to Claus Process for producing Sulphur.
Study of the Sulfur Trioxide Generation Mechanism and Control Method Using We...inventionjournals
In coal fired power plant, especially using sulfur content fossil fuels, much attention in recently paid to sulfur trioxide and sulfuric acid mist emission, because conventional desulfurization system should not be removed, which is installed to meet air quality standard for sulfur dioxide. Sulfur trioxide is highly reactive with water vapor and generally convert to sulfuric acid mist in atmosphere. Sulfuric acid is very fine under-submicron sized particulate matter or droplets. Recently sulfur trioxide cause air pollution and public health, discussion comes out, especially in the United States and Japan, that regulations and guideline should be enlarge the sulfur dioxide to sulfur trioxide and sulfuric acid. Moreover most countries reinforce sulfur oxides emission regulations or guidelines from coal-fired power plant. In this study, focusing that how to control the sulfur trioxide and sulfuric acid mist. Sulfuric acid mist found depending on the flue gas temperature. Generation and conversion rate of sulfur trioxide were measured according to temperature. The absorbent was selected to remove sulfur trioxide and sulfuric acid using wet type desulfurization system which the most proven technology at this moment.
Presentation given by Richard T. J. Porter from ETII, University of Leeds, on "CO2QUEST Typical Impurities in Captured CO2 Streams" at the EC FP7 Projects: Leading the way in CCS implementation event, London, 14-15 April 2014
2. THERMAL POWER PLANTS
Utilize fuel to produce steam for
power generation.
Classified according to type of fuel
used.
Coal power plant
Gas power plant
Oil power plant
3. Combustion of fuel produces
significant amount of air
pollutant.
Depends on the nature of
fuel used
Coal power plant
Fly ash
Sulfur dioxides
Oxides of nitrogen
4. Oil power plant
Sulfur dioxides
Oxides of nitrogen
Combustion of coal is major
important source for particulate air
pollutant than oil.
The amount of fly ash and SO2
depend on the sulfur and ash
content of the fuel used.
5. The major pollutants are
Particulate matter(fly ash and soot)
Sulfur oxides (SO2 &SO3)
Oxides of nitrogen(NO&NO2)
Trace metals Cd, Hg,Pb, Ni,V, As, F
etc. .
Probability of emission of CO and
unburnt carbon.
14. Electrostatic precipitation
Principle
Charging the solid particles suspended in air or
gases by means of gas ions or electrons
produced under a high electric field.
The ash left behind after combustion of coal is
arrested in high efficiency electrostatic
precipitator.
The ash collected in ESP is disposed in ash pond
in the form of slurry.
16. Advantages.
Large gas volume.
Separation of particles of size s as low as .05
microns.
Efficiency (average efficiency 98-99%)
Inexpensive maintenance.
19. Flue Gas Desulfurization
SO2 scrubbing, or Flue Gas Desulfurization processes can be
classified as:
Throwaway or Regenerative, depending upon whether the recovered sulfur
is discarded or recycled.
Wet or Dry, depending upon whether the scrubber is a liquid or a solid.
Flue Gas Desulfurization Processes
The major flue gas desulfurization ( FGD ), processes are :
Limestone Scrubbing
Lime Scrubbing
Dual Alkali Processes
Lime Spray Drying
Wellman-Lord Process
21. Limestone Scrubbing
Limestone slurry is sprayed on the incoming flue
gas. The sulfur dioxide gets absorbed The limestone
and the sulfur dioxide react as follows :
CaCO3 + H2O + 2SO2 ----> Ca+2 + 2HSO3
-+ CO2
CaCO3 + 2HSO3
-+ Ca+2 ----> 2CaSO3 + CO2 + H2O
23. Dual Alkali System
Lime and Limestone scrubbing lead to deposits inside spray tower.
The deposits can lead to plugging of the nozzles through which the
scrubbing slurry is sprayed.
The Dual Alkali system uses two regents to remove the sulfur
dioxide.
Sodium sulfite / Sodium hydroxide are used for the absorption of
sulfur dioxide inside the spray chamber.
The resulting sodium salts are soluble in water,so no deposits are
formed.
The spray water is treated with lime or limestone, along with make-
up sodium hydroxide or sodium carbonate.
The sulfite / sulfate ions are precipitated, and the sodium hydroxide
is regenerated.
24. Lime – Spray Drying
Lime Slurry is sprayed into the chamber
The sulfur dioxide is absorbed by the slurry
The liquid-to-gas ratio is maintained such that the spray dries
before it reaches the bottom of the chamber
The dry solids are carried out with the gas, and are collected
in fabric filtration unit
This system needs lower maintenance, lower capital costs,
and lower energy usage
25. Wellman – Lord Process
Schematic process flow diagram – SO2 scrubbing and recovery
system
26. Wellman – Lord Process
This process consists of the following subprocesses:
Flue gas pre-treatment.
Sulfur dioxide absorption by sodium sulfite
Purge treatment
Sodium sulfite regeneration.
The concentrated sulfur dioxide stream is processed to a
marketable product.
The flue gas is pre - treated to remove the particulate. The sodium
sulfite neutralizes the sulfur dioxide :
Na2SO3 + SO2 + H2O -----> 2NaHSO3
27. Wellman – Lord Process (contd.)
Some of the Na2SO3 reacts with O2 and the SO3 present in the flue
gas to form Na2SO4 and NaHSO3.
Sodium sulfate does not help in the removal of sulfur dioxide, and is
removed. Part of the bisulfate stream is chilled to precipitate the
remaining bisulfate. The remaining bisulfate stream is evaporated
to release the sulfur dioxide, and regenerate the bisulfite.
29. General Methods For Control Of Nox
Emissions
NOx control can be achieved by:
Fuel Denitrogenation
Combustion Modification
Modification of operating conditions
Tail-end control equipment
Selective Catalytic Reduction
Selective Non - Catalytic Reduction
Electron Beam Radiation
Staged Combustion
30. Fuel Denitrogenation
o One approach of fuel denitrogenation is to remove a large part of the nitrogen
contained in the fuels. Nitrogen is removed from liquid fuels by mixing the fuels
with hydrogen gas, heating the mixture and using a catalyst to cause nitrogen in
the fuel and gaseous hydrogen to unite. This produces ammonia and cleaner
fuel.
This technology can reduce the nitrogen contained in both naturally
occurring and synthetic fuels.
31. Combustion Modification
Combustion control uses one of the following
strategies:
Reduce peak temperatures of the flame zone. The methods are :
increase the rate of flame cooling
decrease the adiabatic flame temperature by dilution
Reduce residence time in the flame zone. For this we change the shape
of the flame zone
Reduce Oxygen concentration in the flame one. This can be
accomplished by:
decreasing the excess air
controlled mixing of fuel and air
using a fuel rich primary flame zone
34. Modification Of Operating Conditions
The operating conditions can be modified to achieve
significant reductions in the rate of thermal NOx
production. the various methods are:
Low-excess firing
Off-stoichiometric combustion ( staged combustion )
Flue gas recirculation
Reduced air preheat
Reduced firing rates
Water Injection
35. Tail-end Control Processes
o Combustion modification and modification of operating
conditions provide significant reductions in NOx, but not
enough to meet regulations.
For further reduction in emissions, tail-end control equipment is
required.
Some of the control processes are:
Selective Catalytic Reduction
Selective Non-catalytic Reduction
Electron Beam Radiation
Staged Combustion
37. Selective Catalytic Reduction (SCR)
In this process, the nitrogen oxides in the flue gases are reduced to
nitrogen
During this process, only the NOx species are reduced
NH3 is used as a reducing gas
The catalyst is a combination of titanium and vanadium oxides. The
reactions are given below :
4 NO + 4 NH3 + O2 -----> 4N2 + 6H2O
2NO2 + 4 NH3+ O2 -----> 3N2 + 6H2O
Selective catalytic reduction catalyst is best at around 300 too 400 oC.
Typical efficiencies are around 80 %
38. Selective Non-catalytic Reduction (SNR)
At higher temperatures (900-1000oC), NH3 will reduce
NOX to nitrogen without a catalyst.
At NH3 : NOX molar ratios 1:1 to 2:1, about 40-
60%reduction is obtained.
SNR is cheaper than SCR in terms of operation cost and
capital cost.
Tight temperature controls are needed. At lower
temperatures, un-reacted ammonia is emitted. At
higher temperatures ammonia is oxidized to NO.
39. Electron Beam Radiation
This treatment process is under development, and
is not widely used. Work is underway to determine
the feasibility of electron beam radiation for
neutralizing hazardous wastes and air toxics.
Irradiation of flue gases containing NOx or SOx produce
nitrate and sulfate ions.
The addition of water and ammonia produces NH4NO3, and
(NH4)2SO4
The solids are removed from the gas, and are sold as
fertilizers.
41. Staged Combustion
PRINCIPLE
Initially, less air is supplied to bring about incomplete
combustion
Nitrogen is not oxidized. Carbon particles and CO are released.
In the second stage, more air is supplied to complete the
combustion of carbon and carbon monoxide.
30% to 50% reductions in NOx emissions are achieved.
42. REFERENCES
1. RAO M.N. & RAO H, Air pollution, Tata
McGraw Hill.
2.Mahajan S.P., pollution control in process
industries, Tata McGraw Hill.
