- Subject Code: Air Pollution Control and Management ( 3161308)
- Date:08-06-2022
- Paper solved by Om sonawane
Q.1
(a) Write a short note on Turbo jet Engine.
A turbojet engine is a type of internal combustion engine that uses a turbine to compress air before it enters the combustion chamber. This compressed air is then mixed with fuel and ignited, creating a high-speed jet of hot gases that propels the aircraft forward. Turbojet engines are the most common type of jet propulsion used in modern commercial and military aircraft. They are known for their high speed and long range capabilities, but also have relatively high fuel consumption and noise levels compared to other types of jet engines.
(b) Draw a neat sketch of Bag Filter.
(c) Explain Working principle of Cyclone Separator.
A cyclone separator is a mechanical device that uses centrifugal force to separate particulate matter from a fluid. It works on the principle of centrifugal force, where particles in the fluid are forced to move in a circular motion due to the rotation of the device.
The working of a cyclone separator begins with the fluid entering the device through an inlet pipe. The fluid then enters the cylindrical section of the separator, where it begins to rotate due to the shape of the device. As the fluid moves in a circular motion, the centrifugal force causes the heavier particulate matter to be thrown to the outer walls of the cylinder.
The particulate matter then moves down the cone-shaped section of the separator, where it is collected in a chamber at the bottom of the device. The cleaned fluid, now free of particulate matter, exits the separator through an outlet pipe.
Cyclone separators are commonly used in industrial applications such as power plants, cement plants, and chemical plants to remove dust and other particulate matter from the air. They are also used in air pollution control systems to remove particulate matter from exhaust gases.
Cyclone separator is an efficient, low-cost and low maintenance separator that can be used to separate particulate matter from a fluid. It is commonly used in various industrial settings, including power plants, cement plants, and chemical plants, as well as in air pollution control systems.
Q.2
(a) Enlist Selection criteria of Air Pollution Control Equipments.
Efficiency: The effectiveness of the equipment in removing pollutants from the air is a crucial factor in the selection process. The efficiency of the equipment should be considered in relation to the specific pollutants present in the air stream.
Cost: The cost of the equipment, including initial purchase, installation, and maintenance costs, should be considered when making a selection.
Space Requirements: The equipment should be appropriately sized to fit in the available space and should not take up too much room.
Energy Consumption: The energy consumption of the equipment should be considered in relation to the overall energy consumption of the facility.
Durability: The equipment should be built to last and be able to withstand the harsh conditions of an industrial setting.
(b) Define following terms (along with sketch).
- Impaction
- Interception
- Diffusion
- Impingement
Impaction: Impaction is a method of air pollution control that uses a device, such as a filter or a centrifugal separator, to physically remove pollutants from the air stream. Impaction occurs when particles in the air stream collide with and adhere to the surface of the device.
Interception: Interception is a method of air pollution control that uses a device, such as a screen or a mesh, to physically remove pollutants from the air stream. Interception occurs when particles in the air stream come into contact with and are captured by the device.
Diffusion: Diffusion is a method of air pollution control that uses natural forces, such as wind and thermal currents, to disperse pollutants in the air. Diffusion occurs when pollutants are spread out and diluted by the natural movement of the air.
Impingement: Impingement is a method of air pollution control that uses a device, such as a scrubber or a mist eliminator, to remove pollutants from the air stream by physically intercepting them. Impingement occurs when particles in the air stream come into contact with and are captured by the device. The pollutant particles are often captured by droplets of water or other liquid that are sprayed into the air stream.
(c) Write a short note on venturi scrubber along with sketch.
A venturi scrubber is a type of air pollution control equipment that uses the principle of fluid dynamics to remove pollutants from the air stream. It works by using a venturi nozzle, which is a constriction in the shape of an inverted funnel, to increase the velocity of the air stream. This increased velocity causes a drop in pressure, which creates a suction effect that draws in the pollutants.
The pollutants are then mixed with water or other liquid, which is introduced into the air stream through nozzles located near the venturi nozzle. The pollutants are then trapped in the droplets of water and removed from the air stream.
Venturi scrubbers are commonly used in industrial settings, such as power plants and chemical plants, to remove particulate matter, such as dust and smoke, from the air. They are also used in air pollution control systems to remove pollutants from exhaust gases.
One of the main advantages of venturi scrubbers is their high efficiency in removing pollutants, as well as their compact size and low maintenance requirements. They are also a cost-effective solution for removing pollutants from the air.
OR
(c) Briefly Explain the working principle of Gravity Settling Chamber along with sketch.
The working principle of a gravity settling chamber involves the following steps:
- The air stream containing pollutants enters the chamber through an inlet.
- The air stream then passes through a series of louvers, which slow down the velocity of the air and cause the particulate matter to settle out.
- The particulate matter then falls to the bottom of the chamber, where it is collected in a hopper or a bag filter.
- The cleaned air exits the chamber through an outlet.
Gravity settling chambers are commonly used in industrial settings, such as power plants, cement plants, and chemical plants, to remove particulate matter, such as dust and smoke, from the air. They are also used in air pollution control systems to remove pollutants from exhaust gases.
One of the main advantages of gravity settling chambers is their simplicity and low maintenance requirements. They are also a cost-effective solution for removing pollutants from the air. However, they are not as efficient as other types of air pollution control equipment, such as cyclone separators or venturi scrubbers, and may require a larger space.
Q.3
(a) Briefly explain avalanche multiplication gas molecule in terms of ESP.
Avalanche multiplication in gas molecules refers to the process by which a small number of free electrons in a gas are accelerated by an electric field, causing them to collide with other gas molecules and create more free electrons. This process, also known as electron avalanche, amplifies the current in the gas and is the basis of the operation of devices such as gas detectors and photomultiplier tubes. The electron-stimulated desorption (ESD) process is a similar process, in which a gas molecule adsorbed on a surface is desorbed by the collision with an accelerated electron.
(B) Write a short note on filtration process of Bag filter.
A bag filter, also known as a fabric filter, is a type of air pollution control equipment that uses bags made of porous materials to remove particles from the air. The filtration process in a bag filter works by forcing the contaminated air through the bags, which act as a physical barrier to capture the particles. The bags are typically made of woven or nonwoven fabrics, and the particles are trapped on the surface of the fabric or within the fibers. The clean air exits the filter through the other side of the bags.The bags must be regularly cleaned or replaced, depending on the application and the amount of particulate matter being removed. Bag filters are commonly used in industrial settings such as cement plants, power plants, and chemical plants to control emissions and improve air quality.
(c) Enlist and explain the Advantages and Disadvantages of ESP.
Electrostatic precipitators (ESPs) are devices used to remove particulate matter from industrial exhaust gases. They work by using an electric field to charge the particles in the exhaust gas, which are then collected on oppositely charged plates or electrodes.
Advantages of ESPs include:
- High efficiency: ESPs can remove up to 99.9% of particles from the exhaust gas.
- Low maintenance: ESPs require minimal maintenance and have a long service life.
- Low energy consumption: ESPs use relatively low energy to operate.
- Versatility: ESPs can be used to remove a wide range of particle sizes and types.
Disadvantages of ESPs include:
- High initial cost: ESPs can be expensive to install and maintain.
- Limited applicability: ESPs are not suitable for removing gases or volatile organic compounds.
- Size and space limitations: ESPs can be large and may require a significant amount of space.
- Moisture and temperature limitations: ESPs can be affected by moisture and high temperatures, which can reduce their efficiency.
It is important to note that ESPs should be designed and operated according to the specific needs of the application, as the performance of ESPs can vary greatly depending on factors such as the nature of the pollutants and the operating conditions.
OR
Q.3
(a) Note Down Reaction chemistry of Limestone Scrubbing.
Limestone scrubbing is a process used to remove sulfur dioxide (SO2) from the emissions of power plants and other industrial facilities. The process involves contacting the emissions with a slurry of crushed limestone, which reacts with the SO2 to form calcium sulfite (CaSO3) and water:
SO2 + CaCO3 → CaSO3 + CO2
The calcium sulfite can then be further reacted with oxygen to form calcium sulfate (CaSO4), also known as gypsum:
CaSO3 + O2 → CaSO4
The gypsum can be separated from the scrubbed flue gas and removed as a solid waste product.
It's important to notice that the reaction is pH-dependent and typically an adequate pH of the scrubber water is maintained between 6.5 to 8.0 using lime or soda ash.
(b) Classify NOx control methods.
NOx control methods can be broadly classified into three categories:
- End-of-pipe Control Methods: These methods involve the reduction of NOx emissions after they have been produced, using technologies such as selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR).
- Low-Nox Burners: These methods involve modifying the combustion process to reduce the formation of NOx, such as staged combustion and combustion modification.
- Fuel-based Control Methods: These methods involve modifying the fuel composition or injection method to reduce NOx emissions, such as the use of low-NOx natural gas or fuel staging.
(c) Describe Wellman Lord process along with neat sketch.
The Wellman-Lord process is a method of recovering sulfur from sulfur-containing gases. The process involves the oxidation of sulfur dioxide (SO2) to sulfur trioxide (SO3), which is then cooled and scrubbed to produce liquid sulfuric acid. The process consists of several stages, including:
- Combustion: Sulfur-containing fuel is burned in an oxygen-rich environment to produce SO2.
- Oxidation: The SO2 is then reacted with oxygen in the presence of a catalyst to produce SO3.
- Cooling & Scrubbing: The SO3 is cooled and scrubbed to remove impurities and produce liquid sulfuric acid.
The Wellman-Lord process is a well-established technology that has been used for many years to produce sulfuric acid, which is used in a wide range of industrial and chemical applications, including the production of fertilizers, detergents, and other chemicals. The process is also used to control SO2 emissions from power plants and other industrial facilities.
Q.4
(a) Enlist the advantages of Bag filter.
High Efficiency: Bag filters have a high collection efficiency for particles in the range of 1 to 100 microns.
(b) Draw a neat sketch of ESP.
(c) Draw Air pollution control scheme for Cement and also mentioned sources and types of air pollutants.
OR
Q.4
(a) Explain Alternative Fuels & their utilization.
(B) How to improve efficiency of Cyclone Separator?
c) Draw Air pollution control scheme for Thermal Power plants and also mentioned sources and types of air pollutants.
- Electrostatic precipitators (ESP) or fabric filters (FF) for removing particulate matter (PM)
- Flue-gas desulfurization (FGD) systems for removing sulfur dioxide (SO2)
- Selective catalytic reduction (SCR) systems for removing nitrogen oxides (NOx)
- Carbon capture and storage (CCS) systems for removing carbon dioxide (CO2)
- Particulate matter (PM) from the combustion of fuel and the handling and transport of fuel and ash
- Sulfur dioxide (SO2) from the combustion of fuel containing sulfur
- Nitrogen oxides (NOx) from the combustion of fuel and the high-temperature operation of the power plant
- Carbon monoxide (CO) and volatile organic compounds (VOCs) from the combustion of fuel
- Carbon dioxide (CO2) from the combustion of fuel and other industrial processes
Types of air pollutants:
- Particulate matter (PM)
- Sulfur dioxide (SO2)
- Nitrogen oxides (NOx)
- Carbon monoxide (CO)
- Volatile organic compounds (VOCs)
- Carbon dioxide (CO2)
Q.5
(a) Write and explain three forms of NOx.
NOx is a group of pollutants that are primarily composed of nitrogen oxides, which are formed from the burning of fossil fuels at high temperatures. The three main forms of NOx are:
.jpg)
0 Comments