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Incinerator – Definition, Principle, Types, Applications

What is Incinerator? An incinerator is a device used for the controlled burning of waste materials. Incineration converts waste into ash, flue gas, and heat. ...

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Sourav Bio

What is Incinerator?

An incinerator is a device used for the controlled burning of waste materials. Incineration converts waste into ash, flue gas, and heat. The ash and flue gas are typically released into the atmosphere, while the heat is used to generate electricity or to provide heat for industrial processes or for district heating systems. Incineration is a controversial method of waste disposal, as it can release pollutants into the air if not properly controlled.

Incineration is the controlled combustion of garbage in order to eliminate or convert it into:

  • less dangerous
  • less bulky
  • more manageable components.

Incineration can be used to dispose of a wide variety of waste streams, including municipal solid waste (MSW), commercial, clinical, and some industrial waste types.
After landfilling, incineration is often the second most popular technique of garbage management. Landfill space is growing restricted, thus disposal is a key challenge for incineration. In many cases, incineration of municipal solid waste with energy recovery might be considered as a viable option to landfilling.

Incineration as a method of waste disposal has a relatively long history. The first patent for an incineration-related process was issued in 1874 to Frederick W. Lanchester, who designed a “Destructor” for burning refuse. However, the use of incineration for waste disposal did not become widespread until the early 20th century.

During the 1920s and 1930s, many cities in the United States and Europe began to use incineration as a means of disposing of municipal solid waste. In the post-World War II period, the use of incineration as a waste disposal method continued to grow.

However, in the 1970s and 1980s, concerns about the environmental impact of incineration began to emerge, particularly in relation to the release of pollutants such as dioxins, particulate matter, and heavy metals into the atmosphere. This resulted in stricter regulations, and a decrease in the construction of new incineration facilities in the United States and Europe.

After this period, the technology had been improved and better control equipment were installed, particularly air pollution control equipment and monitoring, which made incineration of waste more reliable and safe.

In recent years, there has been a renewed interest in incineration as a method of waste disposal, particularly in light of increasing pressure to reduce greenhouse gas emissions from landfills. Incineration can be used to generate electricity from the heat produced during the burning process, and many modern incineration facilities are designed to capture and use the heat for power generation or district heating.

Working principle of Incinerator

  • The Incinerator is equipped with a main combustion chamber for burning sludge oil or solid waste, as well as a secondary combustion chamber for burning uncombusted and unburned exhaust gases.
  • The primary burner is installed in the primary combustion chamber.
  • This burner is fed with diesel oil for initial ignition. The sludge oil is then introduced to the main burner until it ignites.
  • The primary burner is then either automatically or manually turned off. The sludge burner is supplied with atomizing air for effective combustion.
  • On the sludge return line, a pressure-regulating valve is installed to control the amount of sludge entering the conversion chamber.
  • The primary burner’s heat will dehydrate and spark the combustion of solid waste and/or sludge oil.
  • The primary combustion chamber’s enormous transmission area enhances the drying and combustion of solid waste.
  • The gases from the primary combustion chamber will burn up in the secondary combustion chamber.
  • The primary and secondary combustion chambers are divided by a wall of ceramic heavy-duty refractory liner.
  • Through the incinerator’s feeding door, solid waste is fed into the device.
  • Note that the primary burner cannot be started if this door is open, but the remainder of the combustion process is identical.
Working principle of Incinerator
Working principle of Incinerator | Image Source: www.marineengineersknowledge.com

Operating procedure of Incinerator

  1. The primary combustion chamber of the incinerator is designed to burn solid waste or sludge oil, while the secondary combustion chamber is designed to eliminate any uncombusted exhaust emissions. In the primary combustion chamber is fitted a primary burner, which is ignited with diesel oil. The sludge oil is then transferred to the primary burner until it ignites.
  2. The primary burner is then manually or automatically turned off.
  3. Atomizing air is supplied to the sludge burner for efficient combustion.
  4. A pressure-regulating valve is installed on the sludge return line to control the amount of sludge entering the conversion chamber.
  5. The primary burner’s heat will dry out and ignite the solid waste, as well as ignite the sludge oil.
  6. The primary combustion chamber’s expansive transmission area enhances the drying and combustion of solid waste.
  7. The gases from the primary combustion chamber will be consumed in the secondary combustion chamber. Separating the primary and secondary combustion chambers is a wall of heavy-duty ceramic refractory liners.
  8. If the waste or garbage is solid, it is fed into the incinerator via the feeding door.
  9. If this door is open, the primary burner cannot be lighted, but the rest of the combustion process continues as normal.

Parts of Incinerator

  1. Fuel storage: This is where the fuel (usually solid waste) is stored before it is burned.
  2. Combustion chamber (primary chamber): This is the primary chamber (combustion chamber) where garbage is loaded and ignited. In the majority of incinerators, ignition is caused by the chamber lining’s ability to retain high temperatures. This is the main chamber where the waste is burned at high temperatures to reduce it to ash and gases.
  3. Secondary Chamber: Secondary Chamber, which is sometimes referred to as the afterburner chamber. In Europe, the United States, Australia, and Canada, it is required by law to prevent the creation of hazardous particles. In several nations, the legislation mandates that all flue gas must reside in the secondary chamber for a minimum of two seconds at 850°C.
  4. Pollution control equipment: This includes filters, scrubbers, and other devices that are used to remove pollutants from the exhaust gases before they are released into the atmosphere.
  5. Ash handling: This includes equipment for collecting and disposing of the ash that is produced during the incineration process.
  6. Flue Stack & The chimney: Flue Stack & The chimney is also known as the flue stack. Most incinerators require a minimum stack height of 3 m. This requirement will be greater in more densely populated places or when atmospheric circumstances so warrant.
  7. Control Panel & Thermocouples: Before any waste is loaded for burning, these components of the incinerator guarantee the chambers are at the appropriate temperature.
  8. Burners: The majority of contemporary incinerators include low NOx or variable gas flow burners.
  9. Electrical equipment: This includes generators, control systems, and other electrical equipment that is used to operate the incinerator.
  10. Cooling system: This includes equipment that is used to cool the exhaust gases before they are released into the atmosphere.
  11. Stack: This is the chimney or pipe that releases the exhaust gases into the atmosphere.

The Incineration Process

  • Combustion: Continuous waste is fed into the furnace by an overhead crane for combustion. To prevent the development of dioxins and carbon monoxide, the waste is burned in a specifically built furnace at a high temperature of > 850oC for more than 2 seconds with a sufficient supply of air to assure complete combustion of the waste. 
  • Boiler/steam turbine: The boiler uses the heat from the combustion to generate steam. The steam subsequently drives the turbine, which is attached to the generator of energy. The created extra heat can also be used for other reasons, such as heating a swimming pool. 
  • Exhaust gas cleaning: The boiler’s exhaust gas is normally cleaned by the following advanced pollution control systems to ensure compliance with demanding environmental regulations. 
  • Dry or Wet Scrubbers: To spray lime powder or fine atomized slurry into the hot exhaust gas to neutralise and remove the acidic pollutants (sulphur oxides, hydrogen chloride). 
  • Activated Carbon Injection: To absorb and eliminate heavy metal and organic contaminants (such as dioxins) from exhaust gas. 
  • Bag house filter: To filter and remove dust and small particles using a bag house filter.
  • Selective Non-Catalytic Reduction: To eliminate a nitrogen oxide (a pollutant that contributes to urban smog) by reacting it with ammonia or urea.
The Incineration Process
The Incineration Process

Input materials

Multiple factors influence the quality and amount of MSWI inputs and outputs:

  • Households and industrial or commercial establishments are waste producers.
  • Waste prevention (theoretically) influences both residential and industrial waste production.
  • Separate collection has a substantial effect on the quantity and quality of incinerable garbage. For instance, the collection of small electrical equipment separately could lower Cu levels in MSWI bottom ash by up to 80%. By separating recyclables and biodegradable waste at the source, the amount of waste requiring treatment is drastically decreased.
  • Residues from waste processing technologies (e.g., sorting of plastics after separate collection) and other items may also be included in the MSWI input.

MSWI residue

Different solid and liquid residual products as well as gaseous effluents are produced by the incineration process. On a moist basis, approximately one-fourth of the waste material remains as solids. The volume of residues equals one-tenth of the initial amount of garbage. The typical leftovers of MSWI combustion by grate are:

  • A quenching/cooling tank collects bottom ash, which consists mostly of coarse noncombustible debris and unburned organic matter, near the combustion chamber’s output.
  • Grate siftings, which consist of relatively fine materials flowing through the grate and accumulating at the bottom of the combustion chamber. Most of the time, it is impossible to separate grate siftings and bottom ash, as they are typically mixed together. Typically, bottom ash and grate siftings account for 20 to 30 percent by mass of the original wet waste.
  • Boiler and economizer ash, which is the coarse fraction of the particles transported by the exhaust gases from the combustion chamber and collected at the heat recovery section. This stream may account for up to 10 percent of the original waste’s mass on a dry basis.
  • Before further treatment of the gaseous effluents, fly ash, the fine particulate matter remaining in the flue gases after the heat recovery units, is removed. On a wet basis, the quantity of fly ash produced by an MSW incinerator is between 1 and 3 percent of the waste input mass.
  • Air pollution control (APC) residues, comprising particle matter caught following reagent injection in acid gas treatment units prior to effluent gas release into the atmosphere. This residue may be solid, liquid, or sludge, depending on whether dry, semi-dry, or wet procedures for air pollution management are utilised. On a wet basis, APC leftovers are typically between 2% and 5% of the original waste.

Types of Incinerator

There are various categories of commercial combustion technologies:

  1. Rotary Kiln Incinerator
  2. Fluidized Bed Incinerator
  3. Moving Grate Incinerator
  4. Multiple Hearth Incinerator
  5. Liquid injection Incinerator
  6. Catalytic combustion chamber
  7. Waste gas flare incinerator
  8. Fixed Grate Incinerator

1. Rotary Kiln Incinerator

Typically, rotary kilns are utilised for the combustion of industrial and hazardous wastes, but they are also utilised in some municipal solid waste incinerators. The basic design consists of two thermal treatment chambers: a slightly inclined primary chamber where waste is fed in (along with the inlet of hot exhaust air with oxygen), rotated, and thermally decomposed by the heat radiation from the secondary chamber: the recombustion chamber located at the back of the kiln where the decomposition air and the remainder of the waste is completely burned with the supply of secondary air. Rotary kilns offer the benefit of emitting low levels of NOx and destroying harmful compounds by thermal means.

Rotary Kiln Incinerator
Rotary Kiln Incinerator

2. Fluidized Bed Incinerator

Recently, the usage of fluidized bed combustion in municipal solid waste incinerators has expanded, while it is still mostly employed for the combustion of hazardous waste. There are different types of fluidized bed combustors (bubbling, rotating, and circulating fluidized bed), but the design principle remains the same: waste particles are suspended by the upward flow of combustion air injected from below so that it appears to be a fluid; the resulting turbulence improves uniform mixing and heat transfer, resulting in a higher combustion efficiency. Enhanced combustion efficiency is a benefit of fluidized bed technology, but its prerequisite is the homogenization of waste inputs in size and heat value, which necessitates considerable pretreatment of waste, often consisting of size reduction and mixing.

Fluidized Bed Incinerator
Fluidized Bed Incinerator | Image Credit: www.gardnerdenver.com

3. Moving Grate Incinerator

A typical combustion design of a municipal solid waste incinerator is a moving grate. A crane deposits waste on the descending grate, which moves into the combustion chamber and eventually descends to deposit the burned residue in an ash pit at the opposite end of the grate. The moving grate is a porous metal bed that allows primary combustion air to pass through from the bottom. By introducing turbulence, secondary combustion air supplied by nozzles above the grate facilitates a full combustion.

Moving Grate Incinerator
Moving Grate Incinerator | Image Credit: www.gardnerdenver.com

4. Multiple Hearth Incinerator

Multiple hearth incinerators are constructed with a column of circular hearths. The rubbish is fed into the incinerator through the top and pushed along a spiral path around each hearth. At the bottom, the material is cooled and released as ash.

Multiple Hearth Incinerator
Multiple Hearth Incinerator

A multiple hearth incinerator is a type of incinerator that uses multiple hearths, or levels, to burn waste. Each hearth is typically heated by an independent burner, and the waste is moved from one hearth to the next by a system of rakes or chains.

One of the main advantages of a multiple hearth incinerator is that it allows for more efficient and complete burning of the waste. The multiple levels and independent burners allow for better control of the combustion process, which can result in lower emissions and a higher overall efficiency.

The main parts of a multiple hearth incinerator are:

  1. Fuel storage: This is where the waste is stored before it is burned.
  2. Combustion chamber: This is where the waste is burned at high temperatures to reduce it to ash and gases.
  3. Hearths: These are the levels or platforms where the waste is burned.
  4. Pollution control equipment: This includes filters, scrubbers, and other devices that are used to remove pollutants from the exhaust gases before they are released into the atmosphere.
  5. Ash handling: This includes equipment for collecting and disposing of the ash that is produced during the incineration process.
  6. Electrical equipment: This includes generators, control systems, and other electrical equipment that is used to operate the incinerator.
  7. Cooling system: This includes equipment that is used to cool the exhaust gases before they are released into the atmosphere.
  8. Stack: This is the chimney or pipe that releases the exhaust gases into the atmosphere.
  9. Rake system: This is the system of rakes or chains that moves the waste from one hearth to the next.

5. Liquid injection Incinerator

In the process of liquid injection incineration, liquid waste is injected directly into the hot gases within the incinerator. This results in the mixing of the liquid waste with the heat and gases. This allows instant oxidation and conversion of the injected waste and contaminants.

Liquid injection Incinerator
Liquid injection Incinerator | Credit: www.tske.co.jp

A liquid injection incinerator is a type of incinerator that is designed to burn liquid waste. In this type of incinerator, liquid waste is atomized into a fine mist and then injected into the combustion chamber, where it is burned at high temperatures.

The main advantage of a liquid injection incinerator is that it allows for the efficient and complete burning of liquid waste. The fine mist of liquid waste allows for a much larger surface area to be exposed to the flame, which results in a more complete burn and lower emissions.

The main parts of a liquid injection incinerator are:

  1. Fuel storage: This is where the liquid waste is stored before it is burned.
  2. Combustion chamber: This is the main chamber where the liquid waste is burned at high temperatures to reduce it to ash and gases.
  3. Atomization equipment: This includes the equipment that is used to atomize the liquid waste into a fine mist before it is injected into the combustion chamber.
  4. Pollution control equipment: This includes filters, scrubbers, and other devices that are used to remove pollutants from the exhaust gases before they are released into the atmosphere.
  5. Ash handling: This includes equipment for collecting and disposing of the ash that is produced during the incineration process.
  6. Electrical equipment: This includes generators, control systems, and other electrical equipment that is used to operate the incinerator.
  7. Cooling system: This includes equipment that is used to cool the exhaust gases before they are released into the atmosphere.
  8. Stack: This is the chimney or pipe that releases the exhaust gases into the atmosphere.
  9. Control system: This includes the control systems and other equipment that is used to operate and monitor the incinerator.

6. Catalytic combustion chamber

Catalytic incinerators are used to remove gaseous pollutants such as volatile organic compounds (VOCs) (Volatile Organic Compounds). These are chemicals that readily transform into gases. Catalytic incinerators increase the rate of oxidation, allowing for the reduction of pollutants at a lower temperature than other types of incinerators. This incinerator would aid in the development of a cost-effective waste management strategy.

Catalytic combustion chamber
Catalytic combustion chamber

A catalytic combustion chamber is a type of combustion chamber that uses a catalyst to aid in the combustion process. The catalyst is a substance that promotes the chemical reactions that occur during combustion, making the process more efficient and reducing the emissions of pollutants.

Catalytic combustion chamber are commonly used in industrial and commercial heating systems, as well as in vehicles and power generation.

The main parts of a catalytic combustion chamber are:

  1. Fuel storage: This is where the fuel (usually gas) is stored before it is burned.
  2. Combustion chamber: This is the main chamber where the fuel is burned and the catalyst is present.
  3. Catalyst: This is the substance that is used to promote the chemical reactions that occur during combustion.
  4. Pollution control equipment: This includes filters, scrubbers, and other devices that are used to remove pollutants from the exhaust gases before they are released into the atmosphere.
  5. Ash handling: This includes equipment for collecting and disposing of the ash that is produced during the combustion process.
  6. Electrical equipment: This includes generators, control systems, and other electrical equipment that is used to operate the combustion chamber.
  7. Cooling system: This includes equipment that is used to cool the exhaust gases before they are released into the atmosphere.
  8. Stack: This is the chimney or pipe that releases the exhaust gases into the atmosphere.
  9. Control system: This includes the control systems and other equipment that is used to operate and monitor the combustion chamber.

The catalytic combustion chamber can also be equipped with a heat exchanger that allows to recover the thermal energy from the exhaust gases and use it to heat water or air.

7. Waste gas flare incinerator

A waste gas flare incinerator is a type of incinerator that is used to burn off waste gases produced by industrial processes. The waste gases are typically composed of volatile organic compounds (VOCs) and other pollutants that must be burned off in order to prevent them from being released into the atmosphere.

The main parts of a waste gas flare incinerator are:

  1. Fuel storage: This is where the waste gases are stored before they are burned.
  2. Combustion chamber: This is the main chamber where the waste gases are burned at high temperatures to reduce pollutants.
  3. Burner: This is the device that is used to ignite the waste gases and provide the heat for the combustion process.
  4. Pollution control equipment: This includes filters, scrubbers, and other devices that are used to remove pollutants from the exhaust gases before they are released into the atmosphere.
  5. Ash handling: This includes equipment for collecting and disposing of the ash that is produced during the combustion process.
  6. Electrical equipment: This includes generators, control systems, and other electrical equipment that is used to operate the incinerator.
  7. Cooling system: This includes equipment that is used to cool the exhaust gases before they are released into the atmosphere.
  8. Stack: This is the chimney or pipe that releases the exhaust gases into the atmosphere.
  9. Control system: This includes the control systems and other equipment that is used to operate and monitor the incinerator.
  10. Ignition system: this include the equipment and system that is used to ignite the waste gases before they are burned.

The waste gas flare incinerator is commonly used in industrial facilities, oil and gas refineries, chemical plants, and other industrial processes where waste gases are produced. The waste gas flare incinerator is designed to burn off the waste gases in a controlled and safe manner, preventing the release of pollutants into the atmosphere.

8. Fixed Grate Incinerator

The usual design for an incinerator is one with a fixed grate and direct flame. It is often the most manufactured and utilised material. Fuel and oxygen maintain the direct flame to enable for the burning of trash.

A fixed grate incinerator is a type of incinerator that uses a fixed grate or bed to burn waste. The waste is placed on the grate, where it is burned at high temperatures to reduce it to ash and gases.

The main advantage of a fixed grate incinerator is that it allows for the efficient and complete burning of solid waste. The waste is continuously fed onto the grate, where it is burned in a controlled manner, resulting in lower emissions and a higher overall efficiency.

The main parts of a fixed grate incinerator are:

  1. Fuel storage: This is where the waste is stored before it is burned.
  2. Combustion chamber: This is the main chamber where the waste is burned at high temperatures to reduce it to ash and gases.
  3. Grate: This is the fixed bed or platform where the waste is burned.
  4. Pollution control equipment: This includes filters, scrubbers, and other devices that are used to remove pollutants from the exhaust gases before they are released into the atmosphere.
  5. Ash handling: This includes equipment for collecting and disposing of the ash that is produced during the incineration process.
  6. Electrical equipment: This includes generators, control systems, and other electrical equipment that is used to operate the incinerator.
  7. Cooling system: This includes equipment that is used to cool the exhaust gases before they are released into the atmosphere.
  8. Stack: This is the chimney or pipe that releases the exhaust gases into the atmosphere.
  9. Feeding system: This includes the equipment and system that is used to feed the waste onto the grate.
  10. Control system: This includes the control systems and other equipment that is used to operate and monitor the incinerator.

A fixed grate incinerator is commonly used for the disposal of municipal solid waste, industrial waste, agricultural waste and other types of waste.

Effective Utilization Of By Products During Incineration

The waste materials are gathered together and subjected to an incinerator process for the burning of organic substances. This cremation method releases waste into the environment, resulting in acid rain, contagious diseases, and wasted heat energy. This research highlights the effective utilisation of heat energy, flue gases, and ash content for the benefit of all living organisms, including humans and animals, as breathing in toxic air has negative side effects.

Ash

The garbage is loaded from the top, and after the incineration process, the ash is removed through the ash door. The ash is in the form of solid chunks that can be used efficiently for both commercial and residential building. It can also be used for road construction.

Flue gases

As a byproduct of the incineration process, a combination of several gases known as flue gas is produced. These gases are discharged into the environment and are the root cause of a variety of ailments, including asthma, lung cancer, and heart attacks, which indirectly leads to the premature death of living things. This research examines the effective utilisation of the gases produced during combustion. Incineration releases mostly nitrogen dioxide, carbon dioxide, sulphur dioxide, water vapour, and trace amounts of oxygen. As sulphur dioxide is a potent oxidizer, sulphur can be recovered from it via the Claus method. Hydrogen sulphide therefore reduces sulphur dioxide to produce elemental sulphur.

SO2 + 2 H2S3 S + 2 H2O

The elemental sulphur can undergo chemical reactions to produce dentally useful sulphur compounds such as sodium thiosulfate. Additionally, nitrogen dioxide, oxygen, and water are byproducts of the combustion process. Using Ostwald’s technique, around 98% of nitric acid can be produced when NO2, oxygen, and water react at 4 to 10 atmospheres at 217 degrees Celsius.

4 NO2 (g) + O2 (g) + 2 H2O (l) 4 HNO3 (aq)

This nitric acid is utilised in crop cultivation. This will increase production and enable farmers to cultivate higher-quality crops.

Heat

Utilizing waste heat by turning it to power is possible. The Seebeck effect is utilised to convert heat to energy in thermoelectric generators. Thermoelectric materials utilise a phenomena that converts the difference in temperature into an electric potential. Bismuth telluride is a widely employed thermoelectric material. Currently, there are frequent power outages in every city in India; this power generation technology will employ waste materials to generate electricity, hence lowering the country’s electricity crisis.

Air Pollution Control

The combustion of municipal solid waste generates significant amounts of flue gases. The flue gases contain leftovers from incomplete combustion as well as a variety of hazardous contaminants. The content of the burned trash and the conditions of combustion determine the contaminants and their concentration. However, these gases contain ash, heavy metals, and other organic and inorganic substances.

There are particles (dust) and gases such as HCl, HF, and SO2 present. Certain toxic substances, such as mercury, dioxins, and NOx, can only be eliminated by the use of sophisticated and expensive chemical treatment procedures. Primary measures, which are initiatives that impede the creation of pollutants, primarily NOx and organic compounds such as dioxins, must be implemented to the greatest extent possible.

The air pollution control (APC) system is composed of electrostatic precipitators, bag house filters, dry, semi-dry, and wet acid gas removal systems, catalysts, and other similar components. Pollutants may be precipitated, adsorbed, absorbed, or transformed by secondary means.

The selection of an APC system is essentially determined by the actual emission restrictions or standards, if applicable, and the intended emission level. In this perspective, the various APC systems might be categorised as fundamental, intermediate, or advanced emission control.

Air Pollution Control Technology

Following are the equipment for the control of air pollution:

  1. Mechanical collectors (cyclones and multicyclones).
  2. Wet scrubbers (such as Venturi scrubbers).
  3. Fabric filters (bag house filters).
  4. Electrostatic precipitators (ESPs).

1. Mechanical collectors (cyclones and multi- cyclones)

Mechanical collectors (such as the cyclone) are ineffective in reducing the dust concentration of flue gas to 150 mg/Nm3 or less. As a result, they are only useful as a part of a more complex flue gas treatment system or as a secondary dust arrestor in hoppers and similar installations. Wet scrubbers (Venturi scrubbers and electric precipitators) can be built to meet a certain emission limit value, such as 100 mg/Nm3. Scrubbers are impractical as the sole or primary air pollution management technology, as the water applied will also remove the majority of the HCl from the flue gas. As a result, it will generate a dust-laden, caustic waste water stream with a pH of approximately 0. Fabric filters have a naturally high cleaning effectiveness, and whether or not they are required, they will remove particles down to around 10 mg/Nm3. However, cloth filters functioning directly on the boiler’s gases are susceptible to fluctuations in temperature, humidity, and spark carryover. In addition, they must be bypassed during the plant’s startup and shutdown.

Cyclone

  • Application • Dust collector
  • Emission level • 500 mg/Nm3

Working principle: The concept of operation is that the dust-laden gas is introduced tangentially and rotated. Dust particles collide with the wall and fall into the conical bottom, where they are collected, as a result of centrifugal forces. The flue gas is discharged through the middle outlet.

2. Venturi scrubber

  • Application • Dust collector
  • Emission level • About 100 mg/Nm3

Working principle: The dust-laden gas accelerates through a throat (a Venturi), atomizing the water that has been injected. Dust particles are collected by water droplets, which are then precipitated in a chamber resembling a cyclonic settling chamber.

3. Electrostatic precipitators

  • Application • Dust collector
  • Emission level • 20-150 mg/Nm3

Working principle: The dust-laden gas is directed into a box containing a number of suspended, grounded collection plates. Between each plate row are discharge electrodes negatively charged by rectified high-voltage DC. This produces an electric field, which charges the particles and causes them to migrate to the plates, generating a coating of dust. The plates are occasionally shook, causing the dust to fall into the bottom hopper.

4. Fabric filter

  • Application • Dust collector
  • Emission level • 10 mg/Nm3

Working principle: The dust-laden gas enters a box, where it is suctioned or compressed through cylindrical bags. A layer of dust accumulates on the surface (most often, the outer surface, in which case the bags are supported by cages). This layer is eliminated via a combination of shaking techniques.

Applications of Incinerator

Incinerators are used in a variety of applications, including:

  1. Municipal solid waste disposal: Incinerators are used to burn municipal solid waste (MSW) in order to reduce the volume of waste and prevent the release of pollutants into the environment.
  2. Hazardous waste disposal: Incinerators are used to burn hazardous waste, such as medical waste, chemical waste, and radioactive waste, in order to reduce the risk of contamination and protect the environment.
  3. Industrial waste disposal: Incinerators are used to burn industrial waste, such as waste from manufacturing processes, in order to reduce the volume of waste and prevent the release of pollutants into the environment.
  4. Sewage sludge disposal: Incinerators are used to burn sewage sludge in order to reduce the volume of waste and prevent the release of pollutants into the environment.
  5. Livestock waste disposal: Incinerators are used to burn waste from livestock operations, such as manure, in order to reduce the volume of waste and prevent the release of pollutants into the environment.
  6. Air pollution control: Incinerators are used to burn off waste gases, such as volatile organic compounds (VOCs), in order to prevent their release into the atmosphere.
  7. Energy recovery: Incinerators can also be used to recover energy from the waste that is burned. This can include electricity, steam, or hot water.
  8. Medical waste: Incineration is the most common method for treatment and disposal of medical waste.
  9. Marine waste: Incineration is an effective way of treating and disposing of waste from ships and boats.
  10. Food waste: Incineration is also a solution for food waste treatment and disposal.
  11. Pharmaceuticals : Incineration is also a solution for pharmaceuticals waste treatment and disposal.

Note that some of these applications may not be allowed in certain countries or regions, as they have different regulations and laws regarding incineration.

Advantages of Incinerator

  1. Volume reduction: Incineration can reduce the volume of waste by up to 90%, making it easier to store and transport the remaining ash.
  2. Pathogen destruction: Incineration can kill bacteria, viruses, and other pathogens that are present in the waste, making it safer to handle and dispose of.
  3. Pollutant destruction: Incineration can destroy pollutants that are present in the waste, such as volatile organic compounds (VOCs), heavy metals, and other toxic compounds.
  4. Energy recovery: Incinerators can recover energy from the waste that is burned, such as electricity, steam, or hot water, making it a more sustainable solution.
  5. Reduced land usage: Incineration reduces the amount of land needed for waste disposal and eliminates the need for landfills.
  6. Reduced greenhouse gas emissions: Incineration reduces the greenhouse gas emissions associated with other waste management methods, such as landfills, which release methane and other gases.
  7. Air pollution control: Incineration can be used to burn off waste gases, such as volatile organic compounds (VOCs), in order to prevent their release into the atmosphere.
  8. Medical waste: Incineration is the most common method for treatment and disposal of medical waste.
  9. Marine waste: Incineration is an effective way of treating and disposing of waste from ships and boats.
  10. Food waste: Incineration is also a solution for food waste treatment and disposal.
  11. Pharmaceuticals : Incineration is also a solution for pharmaceuticals waste treatment and disposal.
  12. Reduced Quantity of Waste: Depending on the components of solid waste, incinerators can reduce the amount of garbage by up to 95 percent and the amount of solid waste by up to 80 to 85 percent. Thus, combustion minimises reliance on landfills. Even though incinerators do not totally eliminate the need for a landfill, they greatly reduce the amount of area required. This is especially beneficial for countries with limited space, such as Japan, because landfills consume vast amounts of land that could be used for other economic purposes. Furthermore, the ash that results from the combustion of garbage is cheaper to carry than unburned waste, and it reduces liability concerns.
  13. Production of Heat and Power: Incineration plants convert garbage into energy that can be utilised to generate electricity or heat. During the 1950s, when energy costs were rising, many nations utilised the heat and energy produced by waste incinerators to generate electricity by means of steam turbines. The created energy can subsequently be used to power the requirements of surrounding residents. Cold-climate nations use the heat from the incinerators to warm their homes and workplaces in the vicinity of the plant. Europe and Japan have integrated incinerators into their modern heating systems, and Sweden meets 8% of its heating demands with garbage incinerators. On average, a single facility may burn up to 300 million tonnes of rubbish every year, transforming a portion of it into energy and lowering the strain on coal-fired power plants, which are an environmental disaster.
  14. Reduced Reliance on Transportation: Due to their low land requirements, waste incineration plants can be located near urban areas. This is helpful since it reduces the distance waste must be transported for disposal. This dramatically reduces the cost of transportation and the emissions of hazardous gases from automobiles during transit, hence reducing the overall carbon footprint. The money saved on transportation can then be used for other purposes, such as promoting the health of the community and fostering the expansion of a city or district.
  15. Better Control Over Odor and Noise: Instead of allowing waste to decompose in the open air, which contributes to air pollution, waste is burned inside a facility where the byproducts of the incineration process can be regulated, resulting in less offensive odour. Moreover, the creation of methane in landfills may result in explosions that create noise pollution, which is unheard of with incineration plants.
  16. Prevents the Production of Methane Gas: The decomposition of garbage in landfills generates huge quantities of methane, a major contributor to global warming. Methane is both harmful to the environment and flammable, making it a safety threat. They are safer and more environmentally friendly because they do not emit methane.
  17. Eliminates Harmful Germs and Chemicals: Incineration plants employ extremely high temperatures to eliminate hazardous microorganisms and chemicals in garbage. Thus, it is a highly successful strategy for decreasing clinical waste.
  18. Operates in Any Weather: Due to the enclosed structure of garbage incinerators, they may operate regardless of the weather. During the rainy season, for instance, waste cannot be put in a landfill since the rain will likely wash dangerous chemicals into the ground and form leachate, poisoning the subsurface water and surrounding land. Waste cannot be dumped while there is wind because it will be blown into the environment. In contrast, incinerators are not susceptible to weather fluctuations because they burn garbage without leaking. Incineration plants operate 24 hours a day and are more effective at trash management than landfills.
  19. It has a Computerized Monitoring System: Governments, towns, institutions, and commercial waste management firms can purchase an incinerator equipped with a computer device for the diagnosis of the majority of issues. This will allow operators to detect an issue before it worsens and becomes prohibitively expensive to rectify. A computer will also facilitate the work of operators, as they will be able to monitor the incinerator plant’s operational efficiency.

It is important to note that while incineration has many benefits, it also has some limitations and it is important to ensure that it is properly controlled and regulated to minimize negative impact on the environment and human health.

Disadvantages of Incinerator

Incinerators also have several disadvantages, including:

  1. High costs: Incineration can be expensive to build, operate and maintain.
  2. Air pollution: Incineration can release pollutants into the air, such as particulate matter, dioxins, and other pollutants.
  3. Ash disposal: Incineration produces ash, which can contain pollutants and heavy metals. This ash must be properly managed and disposed of.
  4. Odor: Incineration can produce odors that can be unpleasant for nearby residents.
  5. Noise: Incineration can produce noise that can be disruptive for nearby residents.
  6. High Operating Costs: The building of a waste incineration facility is a costly endeavour, mostly due to the infrastructure and equipment required to construct an incineration plant. In addition to its high initial cost, a trash incineration plant necessitates the hiring of skilled and devoted operators. The regular maintenance of the plant, which grows as the plant matures, adds another significant operating expense to a waste incinerator.
  7. Health risks: Incineration can pose health risks to workers and nearby residents, such as respiratory problems, cancer, and other health issues.
  8. Limited waste types: Incineration is not suitable for all types of waste, such as wet or bulky waste, and certain types of hazardous waste.
  9. Not a recycling solution: Incineration is not a recycling solution and it doesn’t allow to recover or separate the recyclable materials.
  10. Environmental Racism: It refers to any policy, practise, or instruction that disadvantages individuals, groups, or communities based on race or colour, whether intentionally or unintentionally. These so-called waste-to-energy plants are typically constructed in less affluent regions, particularly those with poor representation. This is a regular occurrence among minority groups and has severe negative effects on the local population.
  11. Does Not Contribute to Waste Reduction: Incineration is not conducive to recycling or trash reduction. This is not a strategy employed by any community. Priority should be placed on minimising trash and recycling the majority of it. Simply combusting the majority of waste without recycling part of it may create environmental harm since it may stimulate additional waste creation.
  12. Not a sustainable solution: Incineration uses fossil fuels and it has environmental impacts and carbon footprint.
  13. Dependence on fuel: Incineration requires a steady supply of fuel to operate, which may not always be available or sustainable.
  14. Not suitable for every location: Incineration may not be suitable for every location, depending on factors such as population density, air quality, and zoning regulations.

It is important to note that while incineration has some disadvantages, it can be an effective waste management solution when properly designed, operated, and regulated. It is important to weigh the benefits and drawbacks of incineration and consider other waste management options before implementing an incineration program.

Precautions

When operating an incinerator, it is important to take certain precautions in order to minimize negative impacts on the environment and human health. These precautions include:

  1. Adequate pollution control: Incinerators must be equipped with adequate pollution control equipment, such as filters, scrubbers, and other devices, to prevent the release of pollutants into the air.
  2. Proper ash disposal: Incineration produces ash, which can contain pollutants and heavy metals. This ash must be properly managed and disposed of in a way that minimizes the risk of contamination.
  3. Emission monitoring: Incinerators should be regularly monitored for emissions to ensure that they are operating within legal limits and to identify any potential problems.
  4. Proper maintenance: Incinerators must be properly maintained to ensure that they are operating efficiently and to minimize the risk of breakdowns or accidents.
  5. Emergency preparedness: Incinerators should have emergency preparedness plans in place to respond to any accidents or malfunctions that may occur.
  6. Training: Incinerator operators should be properly trained to operate the equipment safely and effectively.
  7. Compliance with regulations: Incinerators must comply with all local, state, and federal regulations and laws, including air quality regulations and waste management regulations.
  8. Community engagement: Incinerator operators should engage with the local community and be transparent about their operations, providing information about the facility’s performance and addressing any concerns that may arise.
  9. Not suitable for every type of waste: Incineration is not suitable for all types of waste, such as wet or bulky waste, and certain types of hazardous waste.
  10. Not recycling solution: Incineration is not a recycling solution and it doesn’t allow to recover or separate the recyclable materials.
  11. Not sustainable solution: Incineration uses fossil fuels and it has environmental impacts and carbon footprint.

By following these precautions, incinerator operators can minimize negative impacts and help ensure that incineration is used responsibly and sustainably.

What we Cannot burn in incinerator?

There are certain types of materials that should not be burned in an incinerator, as they can release harmful pollutants into the air or cause damage to the incinerator itself. Some examples of materials that should not be burned in an incinerator include:

  • Hazardous waste, such as chemicals, batteries, and pesticides, as they can release toxic fumes when burned.
  • Medical waste, such as sharps, pathological waste, and biohazardous waste, as they can pose a risk of infection to workers handling the waste and to people living near the incinerator.
  • Asbestos, as it can release fibers into the air when burned, which can be harmful to human health.
  • Plastic, as it can release harmful pollutants when burned and can damage the incinerator itself.
  • Whole tires, as they can release harmful pollutants when burned, such as dioxins, furans, and heavy metals, and can also damage the incinerator.
  • Electronic waste, as it can release lead, mercury, and other toxic pollutants when burned.

It’s important to note that regulations vary by location and the specific type of incinerator being used. Always check with local authorities for specific regulations regarding what can and cannot be burned in an incinerator.

Why are incinerators used?

Incinerators are used for a variety of reasons, including waste disposal, energy generation, and pollution control.

  • Waste disposal: Incineration is used as a method of waste disposal because it reduces the volume of solid waste and eliminates the need for landfills. Incineration can be used to dispose of a wide variety of waste materials, including municipal solid waste, medical waste, hazardous waste, and sewage sludge.
  • Energy generation: Incineration can also be used to generate electricity by using the heat generated during the burning process to power a steam turbine. This is known as waste-to-energy (WTE) technology. WTE plants can generate electricity from a variety of waste materials, including municipal solid waste and agricultural waste.
  • Pollution control: Incineration can be used as a pollution control measure by destroying pollutants before they are released into the environment. This is often used for the treatment of hazardous waste, such as industrial chemicals and pesticides, to prevent their release into the air, water, or soil.
  • Medical waste: Medical waste is defined as any waste materials that have been contaminated with blood, body fluids, or other potentially infectious materials. It’s considered one of the most effective ways to destroy medical waste, as it uses high temperatures to sterilize the waste and reduce its volume.

It’s important to note that regulations vary by location and the specific type of incinerator being used. Always check with local authorities for specific regulations regarding what can and cannot be burned in an incinerator.

Is incineration better than recycling?

It depends on the specific context and materials in question. Both incineration and recycling have their own advantages and disadvantages, and the best approach will depend on the specific waste materials, local regulations and resources, and the overall goals of waste management.

  • Incineration: Incineration is an effective way to reduce the volume of waste and eliminate the need for landfills. It also can generate electricity in some cases. However, it can be expensive to build and operate an incinerator, and it can release pollutants into the air if not properly controlled. Additionally, incineration doesn’t recover valuable resources like recycling does.
  • Recycling: Recycling is a cost-effective way to conserve natural resources and reduce pollution by reducing the need to extract new raw materials. It also creates jobs and economic activity in the recycling and manufacturing industries. But, not all materials are recyclable and some recyclable materials need to be cleaned, sorted and processed before being recycled, which can be expensive.

So, when it comes to waste management, it’s important to consider the overall goals, and choose the approach that will best achieve those goals in a cost-effective and environmentally friendly way. Both incineration and recycling can play a role in achieving these goals, but it’s important to evaluate the specific materials and local resources and regulations to determine which approach is best.

How is incineration harmful?

Incineration can be harmful if not properly controlled, as it can release pollutants into the air and affect human health and the environment. Some of the potential harms of incineration include:

  • Air pollution: Incineration produces flue gases that contain pollutants such as particulate matter, dioxins, furans, and heavy metals, which can harm human health and the environment if not properly controlled.
  • Greenhouse gas emissions: Incineration produces greenhouse gases such as carbon dioxide, which contribute to climate change.
  • Resource depletion: Incineration destroys valuable resources that could be recycled or reused.
  • Noise pollution: Incineration facilities can produce noise pollution that can disturb local communities.
  • Health risks: The emissions from incineration can contain harmful pollutants that can have adverse effects on human health, such as respiratory problems, cancer, and other illnesses.

It’s important to note that regulations vary by location and the specific type of incinerator being used. Always check with local authorities for specific regulations regarding what can and cannot be burned in an incinerator. With proper control and management, modern incineration facilities are designed to minimize the release of pollutants into the air and meet the stringent emission standards set by the authorities to minimize the potential harm.

FAQ

What incinerator means?

An incinerator is a device used to burn waste materials, typically as a method of disposal. Incineration is a process of thermally oxidizing waste materials in the presence of oxygen to convert them into ash, flue gas, and heat. Incineration is used to dispose of a wide variety of waste materials, including municipal solid waste, medical waste, hazardous waste, and sewage sludge. It is also used to generate electricity in some cases.

What is incinerator in hospital?

An incinerator in a hospital is a device used to burn medical waste, which is defined as any waste materials that have been contaminated with blood, body fluids, or other potentially infectious materials. Medical waste can include sharps (such as needles, scalpels, and syringes), pathological waste (such as tissue samples), and biohazardous waste (such as lab cultures and animal carcasses).
Incineration is considered one of the most effective ways to destroy medical waste, as it uses high temperatures to sterilize the waste and reduce its volume. Incinerators used in hospitals typically have advanced filtration systems in place to capture any pollutants that may be released during the burning process. These systems may include scrubbers and filters that remove pollutants such as dioxins, furans, and particulate matter.
Hospital incinerators are regulated by local authorities and are required to meet specific emission standards. They are also typically subject to regular inspections to ensure they are operating safely and effectively.

What is the principle of incinerator?

An incinerator is a device that burns waste materials in the presence of oxygen to convert them into ash, flue gas, and heat. The basic principle of an incinerator is thermally oxidizing the waste materials to reduce the volume of the waste and eliminate the need for landfills. The process of incineration is typically divided into three main stages: drying, combustion, and post-combustion. The drying stage removes moisture from the waste, the combustion stage burns the waste at high temperatures, and the post-combustion stage treats the flue gases to remove pollutants before they are released into the atmosphere. Incinerators are equipped with advanced filtration systems to capture pollutants, including scrubbers and filters, to remove pollutants such as dioxins, furans, and particulate matter. This ensures that the incineration process is safe and environmentally friendly.

Do incinerators pollute air?

Incinerators can release pollutants into the air if not properly controlled. Incineration process produces flue gases that contain pollutants such as particulate matter, dioxins, furans, and heavy metals. These pollutants can be harmful to human health and the environment. Therefore, it is important that incinerators are equipped with advanced filtration systems, such as scrubbers and filters, to remove these pollutants before they are released into the atmosphere.

Additionally, the emissions from incinerators are regulated by local authorities and are required to meet specific emission standards, which vary by location. Regular inspections are also conducted to ensure that the incinerators are operating safely and effectively.

However, with proper control and management, modern incineration facilities are designed to minimize the release of pollutants into the air and meet the stringent emission standards set by the authorities.

Can plastic be incinerated?

Plastic can be incinerated, but it’s not considered a recommended method of disposal due to the potential negative environmental and health effects. Plastic releases pollutants such as hydrochloric acid, sulfur dioxide, and dioxins when burned, which can harm human health and the environment. Additionally, burning plastic can also damage the incinerator itself.

Plastic is not considered a suitable waste for incineration since it is not a good source of energy, it has low calorific value, and it produces toxic pollutants when burned. Instead, plastic waste should be recycled or processed in a facility specifically designed to handle plastic waste, such as a pyrolysis or gasification plant.

It’s important to note that regulations vary by location and the specific type of incinerator being used. Always check with local authorities for specific regulations regarding what can and cannot be burned in an incinerator.

References

  • Zjup, Wdse & Bourtsalas, Athanasios & Huang, Qunxing & Zhang, Hanwei & Themelis, Nickolas. (2020). Energy recovery in China from solid wastes by the moving grate and circulating fluidized bed technologies https://rdcu.be/b3jg1. 2. 27-36.
  • Lombardi, F., Lategano, E., Cordiner, S., & Torretta, V. (2013). Waste incineration in rotary kilns: a new simulation combustion tool to support design and technical change. Waste Management & Research, 31(7), 739–750. doi:10.1177/0734242×13484187
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  • https://www.rpi.edu/dept/chem-eng/Biotech-Environ/incinerator.html
  • https://slideplayer.com/slide/10814404/
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  • https://www.marineengineersknowledge.com/2021/06/incinerator.html
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Citation

APA

Sourav Bio. (January 12, 2023).Incinerator – Definition, Principle, Types, Applications. Retrieved from https://microbiologynote.com/incinerator-definition-principle-types/

MLA

Sourav Bio. "Incinerator – Definition, Principle, Types, Applications." Microbiology Note, Microbiologynote.com, January 12, 2023.

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