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Difference Between Water Tube Boiler And Fire Tube Boiler

October 1, 2024 by Sanjeev Kumar

Difference between Water Tube Boiler and Fire Tube Boiler

In today’s article we are going to learn about the difference between water tube boiler and fire tube boiler or in simple words Fire Tube Boiler Vs Water Tube Boiler.

We know that boiler is used onboard for power generation and it is one of the most important thing on ship.

Boiler is broadly categorised into water tube boiler and fire tube boiler. And since they are categorised differently this means that there must be some differences between them either in functioning, maintaining, running or economical differences. This article is all about their differences.

Difference between water tube and fire tube boiler

Fire Tube Boiler Vs Water Tube Boiler

Water Tube Boiler	Fire Tube Boiler
1. The water flows inside the tube and the hot combustion gases flows outside the tube.	1. The hot gases flows inside the tube and the water is outside the tube.
2. These are generally high pressure boiler ranging up to 70-100 Bar.	2. These are generally low or medium pressure boiler up to 25 Bar.
3. Faster rate of steam Production.	3. Lower rate of steam Production.
4. More efficient	4. Less efficient
5. These boilers are mostly externally fired.	5. These are internally fired. The furnace is placed at one end of the Fire tube.
6. Suitable for large scale power plants.	6. Suitable for small scale power plants.
7. Since the operating pressure is high, the risk of explosion is also high.	7. Risk of explosion is less, as less operating pressure.
8. Occupies less floor space.	8. Occupies large floor space.
9. Because of complexity, skilled person is required to operate.	9. Less complex, less skill required.
10. Easy to clean as it is externally fired	10. Difficult to clean as internally fired.
11. The shell diameter is less.	11. The diameter of shell is more.
12. Easy to carry out maintenance.	12. Difficult to carry out maintenance
13. Since water flows inside the tube, treatment of water is necessary to prevent deposit formation.	13. Treatment of water is not necessary.
14. More environment friendly	14. Less environment friendly
15. Operating cost is high	15. Operating Cost is less.
16. Examples: Babcock and Wilcox Boiler, Stirling Boiler, La-mont Boiler, Benson Boiler, Loeffler Boiler, Yarrow Boiler	16. Examples: Simple Vertical Boiler, coachran boiler, Lancashire Boiler, Cornish Boiler, Scotch Boiler, Locomotive Boiler, Velcon Boiler.

Difference between water tube boiler and fire tube boiler in a descriptive format | Fire Tube Boiler Vs Water Tube Boiler

Fire Tube Boiler

In fire tube boiler, as the name suggest Fire Tube (i.e Fire in Tube) the hot combustion gases ( flue gases) are passed through the tubes which are arranged inside the cylindrical drum and the outside of the tubes are surrounded by the water.

The heat transfer takes place between the hot gases and the surrounded water through the tubes. This heats up the water and convert it into steam.
Fire Tube boilers are simple in construction as compared water tube boilers and are used as their alternative because of being cheaper.

These are generally used in small scale industries as the operating pressure of fire tube boilers are low.

Other advantages of fire tube boilers are that they have compact size and have the ability to handle the fluctuations in steam demand more efficiently.
There are also certain disadvantages of Fire tube boiler like it’s efficiency is low, it takes longer time to convert that amount of water into the steam, not able to cope up with sudden increase in load.

Water Tube Boiler

Now coming to the water tube boiler (i.e water in the tube), the water runs inside the tube and the hot gases are passed over the outer surface of the tube.

The heat is transferred from the hot gases to the water in the tubes and it gets converted into steam.

Since the steam is generated in the tubes , the water tube boilers can operate at higher pressure than the fire tube boilers and hence they are used in large scale production that requires high pressure and high steam output.

Advantages

Water tube boilers are generally provided with more than one burner and we can use these burner either individually or in parallel combination for a single furnace.

This provides a way to have controlled shutdowns so that maintenance can be carried out without shutting off the boiler entirely.

Also the burners can be used to operate at different loads.
Water tube boilers are also provided with Programmable Logic Controller for controlling and maintaining proper functioning of the burners provided.

They also control the super heater and feed water systems.
As the volume of area of production of steam is less in water tube boiler the water tube boilers are able to produce high pressure steam and at a faster rate than the fire tube boiler.

They can also produce super heated or saturated steam according to the design and the place where they are required. They are able to operate at higher pressure.
The water tube boiler can be constructed to use high-ash fuels in conjunction with the soot blowers and proper Ash handling and flue gas cleanup equipment to maintain environmental regulations.

Disadvantages

Though we have seen the various advantages of the water tube boiler but there are certain disadvantages also.

The capital cost of water tube boiler is very high and the size of the water tube boiler is large as compared to fire tube boiler which bring it to a point that it is mostly constructed on the site where it has to be used.
Because of the use of control systems the complexity and it’s cost increases more.

And for working on it a proper training is required.
Now that we have seen the descriptive difference between water tube boiler and fire tube boiler.

Now it is more easy to remember in point form rather than the description, though the description gives you a better understanding of the differences.

Why water tube boiler is more efficient than fire tube boiler ?

In fire tube boilers, flue gases need to heat up a large amount of water and are therefore slow and inefficient.

Because of their slow operation, more heat is lost to the surroundings. In the water tube boilers, flue gases pass through the water tubes and deal with less water.

They’re fast in operation, therefore, and less heat is wasted in the surroundings.

So, They’re more efficient.

Why can’t a fire tube boiler be made with a high capacity as a water tube boiler ?

Fire tube boilers are used for small capacity & less pressure boilers because the heat is explored to evaporate the water is less available also the heat is less available. But in the water tube Boilers area available to heat the water is more because the flue gas flows around the tubes. It is therefore used for higher capacity and high pressure of approximately 127 Kg/cm2 or more.

What are the differences between a tank boiler and a water tube boiler?

You may be referring to “Fire-tube” vs. “Water tube” In the former, the entire tank is filled with pressurized water and steam with fire flowing through the tank in pipes. This form is no longer used except in historic installations.

Excessive pressure due to technological malfunction or operator error may cause the entire tank to burst, killing people nearby. The sort of water pipe will never explode because all the pressure is in the pipes and the tank has hot gases. If the tube splits, the steam spills harmlessly into the firebox.

So these were some of the basic difference between Water tube Boiler and Fire tube Boiler which are covered in this article in tabular as well as descriptive form. Fire Tube Boiler Vs Water Tube Boiler is one of the common things that people generally ask. If You liked this article, please share it with your friends and give your feedback in the comment below.

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Synergy Maritime Exam

Boiler gauge glass blow through procedure : Easy Step

September 27, 2024July 5, 2024 by Sanjeev Kumar

Boiler Gauge Glass Blow Through Procedure : Blow through of Boiler Gauge Glass is Done to ensure accurate reading of the water level in the boiler and to remove any debris, sediment, or scale that may have accumulated in the gauge glass and its connections.

Boiler gauge glass blow through procedure Step by Step

Step-by-Step Instructions:

Isolate the Steam Connection: Close the steam valve to prevent steam from entering the gauge glass.
Isolate the Water Connection: Close the water valve to prevent water from entering the gauge glass.
Drain the Gauge Glass: Open the drain cock located at the bottom of the gauge glass to allow the contents to drain completely.
Wait for Drainage: Allow the gauge glass to drain completely before proceeding.
Clear the Steam Connection: Open the steam valve to allow steam to flow through the connection and clear any debris or condensate.
Close the Steam Connection: Close the steam valve to prevent further steam flow.
Clear the Water Connection: Open the water valve to allow water to flow through the connection and clear any debris or sediment.
Wait for Complete Drainage: Allow the water connection to drain completely before proceeding.
Close the Drain Cock: Close the drain cock to prevent further drainage.
Refill the Gauge Glass: Open the water valve to allow water to refill the gauge glass.
Open Steam Valve : Open the steam valve to check the water level in the boiler, ensuring it is within the recommended range.

Note: This procedure should be performed daily to ensure the accuracy and reliability of the boiler’s water level indication.

procedure of Boiler Gauge Glass Blow Through in Table form

Step	Procedure
1.	Isolate the Steam Connection
	– Close the steam valve to prevent steam from entering the gauge glass.
2.	Isolate the Water Connection
	– Close the water valve to prevent water from entering the gauge glass.
3.	Drain the Gauge Glass
	– Open the drain cock located at the bottom of the gauge glass to allow the contents to drain completely.
4.	Wait for Drainage
	– Allow the gauge glass to drain completely before proceeding.
5.	Clear the Steam Connection
	– Open the steam valve to allow steam to flow through the connection and clear any debris or condensate.
6.	Close the Steam Connection
	– Close the steam valve to prevent further steam flow.
7.	Clear the Water Connection
	– Open the water valve to allow water to flow through the connection and clear any debris or sediment.
8.	Wait for Complete Drainage
	– Allow the water connection to drain completely before proceeding.
9.	Close the Drain Cock
	– Close the drain cock to prevent further drainage.
10.	Refill the Gauge Glass
	– Open the water valve to allow water to refill the gauge glass.
11.	Verify Water Level
	– Open the steam valve to check the water level in the boiler, ensuring it is within the recommended range.

Note: This procedure should be performed daily to ensure the accuracy and reliability of the boiler’s water level indication. Each step ensures proper isolation, draining, clearing, and verification of the gauge glass, maintaining operational safety and efficiency.

purpose of Boiler gauge Glass

The purpose of this procedure is to:

To ensure the accuracy and reliability of the boiler’s water level indication.
Remove any debris, sediment, or scale that may have accumulated in the gauge glass and its connections.
Prevent any potential damage to the gauge glass or boiler due to clogging or corrosion.
Maintain the overall safety and efficiency of the boiler operation.

Why need to blow down the boiler water ?

Boiler blow down is made to reduce the density of salt and to remove the dissolved and suspended solids, also the floating solid impurities in the boiler system.

If there are not removed from the boiler water system, foaming, priming, corrosion will occur in the boiler steam space and feed water system.

Wikipedia

Electric Arc Furnace – Complete Process, Parts & Application

September 28, 2024September 30, 2023 by Aman Kumar

What is electric arc furnace

An electric arc furnace (EAF) is a type of industrial furnace used for melting metals, particularly steel and iron, through the use of an electric arc. It’s a crucial tool in the steelmaking industry and is known for its efficiency and flexibility in producing various steel grades.

parts of electric arc furnace

An electric arc furnace (EAF) is a complex industrial furnace with several key parts and components that work together to melt and refine metals. Here are the main parts of an electric arc furnace:

Shell: The shell is the outer structure of the EAF, typically made of steel and lined with refractory materials. It provides structural support and helps contain the heat and materials inside the furnace.
Lid or Roof: The lid, also known as the roof, is the top cover of the furnace. It can be lifted or rotated to allow for charging of raw materials and removal of molten metal and slag. It also contains openings for electrodes and various ports for operations like oxygen injection.
Electrodes: Electrodes are typically made of graphite or other conductive materials and are inserted through openings in the roof. They create an electric arc when electricity is passed through them, generating the high temperatures needed for melting metals.
Furnace Hearth: The hearth is the bottom portion of the furnace, where molten metal collects. It is lined with refractory materials that can withstand the extreme heat of the molten metal.
Refractory Lining: The refractory lining is a layer of heat-resistant materials that line the inside of the furnace, including the walls, roof, and hearth. These materials protect the steel shell from the intense heat generated during the melting process.
Electrode Holders: Electrode holders secure the electrodes in place and allow for adjustments to control the position of the electric arc.
Transformer: Electric arc furnaces require a high voltage electrical supply to generate the electric arcs. A transformer is used to step up the voltage from the power source to the level needed for the EAF operation.
Electrical System: The electrical system includes components such as transformers, circuit breakers, switches, and control panels to manage the flow of electricity to the electrodes and other furnace systems.
Cooling System: EAFs generate a tremendous amount of heat, and a cooling system is essential to prevent overheating and maintain the integrity of the furnace components. Water-cooled panels, pipes, and cooling jackets are commonly used for this purpose.
Gas Injection System: Some EAFs are equipped with a gas injection system that introduces gases like oxygen or argon into the furnace. These gases can affect the melting process and help in refining the metal.
Dust and Fume Collection System: EAF operations can generate dust and fumes, which need to be collected and filtered to reduce environmental impact and protect worker health.
Tapping System: A tapping system includes equipment such as a tap hole, tap spout, and ladle, which are used to safely remove molten metal and slag from the furnace for further processing or casting.
Control and Automation System: Modern EAFs are often equipped with sophisticated control and automation systems that monitor and regulate various parameters, such as temperature, electrode position, and power input, to ensure efficient and precise melting.

These are the primary components of an electric arc furnace, and their design and operation can vary depending on the specific requirements of the metal production process and the type of materials being melted and refined.

Electric arc furnace process

The electric arc furnace (EAF) process is a step-by-step method used in the melting and refining of metals, particularly steel. Here’s a simplified step-by-step description of how an EAF typically operates:

Charging: The process begins by loading the raw materials into the EAF. These materials can include scrap steel, iron ore, alloying elements, and fluxes. The materials are typically charged from the top of the furnace through an opening in the roof or lid.
Electrode Placement: Electrodes, usually made of graphite, are positioned in the furnace roof’s electrode holders. These electrodes will create an electric arc, generating the intense heat needed for melting the materials.
Start-Up: The EAF is energized, and electrical power is supplied to the electrodes. When the electrodes touch the materials in the furnace, an electric arc is established between the electrodes and the charge materials, initiating the melting process.
Melting: The electric arc generates extremely high temperatures, often exceeding 3,000 degrees Celsius (5,432 degrees Fahrenheit). This intense heat melts the materials in the furnace, including the scrap steel and any other added components like alloys.
Oxygen Injection (Optional): In some cases, oxygen or other gases can be injected into the furnace to accelerate the combustion of impurities, aid in chemical reactions, and enhance the melting process. This step is optional and depends on the specific steelmaking process.
Chemical Reactions: As the materials melt, chemical reactions occur within the furnace. Impurities in the scrap steel are oxidized and removed as slag, while alloying elements are added to achieve the desired steel composition.
Temperature Control: The EAF’s control system continuously monitors and adjusts the electric arc’s power and position to maintain the desired temperature and composition of the molten metal.
Sampling and Analysis: Samples of the molten metal are periodically taken to assess its chemical composition and temperature. This information helps operators make necessary adjustments to meet quality standards.
Refining: Depending on the steel grade being produced, additional refining steps may be performed. These can include adding fluxes or alloying materials to achieve specific metallurgical properties.
Tapping: When the molten metal has reached the desired composition and temperature, a tap hole in the bottom of the furnace is opened, allowing the molten steel to flow into a ladle or casting vessel. Simultaneously, slag is also removed from the furnace.
Ladle Transfer: The molten steel is transferred from the EAF to a ladle for further processing. It may be transported to a secondary refining process, such as a ladle furnace, to further refine the steel’s composition and temperature.
Casting: The refined molten steel is cast into various shapes, such as slabs, billets, or ingots, depending on the intended use. The casting process can vary depending on the specific steel product being produced.
Cooling and Solidification: The cast steel is allowed to cool and solidify, forming the final product. The cooling process can be controlled to achieve specific microstructures and mechanical properties.
Quality Control: The finished steel products are subjected to quality control measures to ensure they meet the required standards and specifications.

The EAF process offers flexibility, efficiency, and control in steelmaking, making it a preferred method for producing a wide range of steel products while also recycling scrap metal. The specific steps and details of the process can vary depending on the type of steel being produced and the equipment used in the EAF.

Application of electric arc furnace

Electric arc furnaces (EAFs) have a wide range of applications, primarily in the metallurgical and manufacturing industries. Here are some key applications of electric arc furnaces:

Steel Production: EAFs are commonly used for steelmaking. They melt scrap steel, iron ore, and various alloying elements to produce different grades of steel. This process is essential for manufacturing a wide range of steel products, including construction materials, automotive components, and machinery parts.
Stainless Steel Production: EAFs are crucial for producing stainless steel, which is highly resistant to corrosion and heat. The EAF process allows for precise control over the composition of stainless steel, making it suitable for various applications in the chemical, food processing, and medical industries.
Ferroalloy Production: Electric arc furnaces are used to produce ferroalloys, which are alloys of iron with other elements like silicon, manganese, or chromium. Ferroalloys are essential for enhancing the properties of steel and manufacturing specialized alloys used in various industries.
Cast Iron Production: Some EAFs are designed for producing cast iron, which is used in the production of pipes, fittings, engine blocks, and other heavy-duty applications.
Non-Ferrous Metal Production: While EAFs are most commonly associated with steel and iron production, they can also be used to melt and refine non-ferrous metals like copper, aluminum, and nickel. This is important for recycling and refining these metals.
Recycling: EAFs play a critical role in recycling scrap metal. They can quickly melt down and refine various types of scrap, reducing the environmental impact of metal production and conserving natural resources.
Specialty Alloys: Electric arc furnaces are used to create specialty alloys with precise chemical compositions. These alloys find applications in aerospace, electronics, and other high-tech industries.
Heat Treatment: In addition to melting metals, EAFs can be used for heat treatment processes, such as annealing or tempering, to improve the mechanical properties of steel and other materials.
Research and Development: EAFs are used in research and development settings to experiment with new alloy compositions and refine manufacturing processes.
Environmental Remediation: In some cases, EAFs are employed for the decontamination and treatment of hazardous waste materials, helping to neutralize pollutants and reduce their environmental impact.

Electric arc furnaces are versatile and efficient tools in the manufacturing world, and their applications continue to expand as technology advances and industries seek more sustainable and cost-effective ways to produce metals and alloys.

Advantages of electric arc furnace

Electric arc furnaces (EAFs) offer several advantages in various industrial applications, making them a popular choice for melting and refining metals. Here are some of the key advantages of using electric arc furnaces:

Energy Efficiency: EAFs are generally more energy-efficient than other types of furnaces, such as blast furnaces. They can quickly reach and maintain high temperatures, reducing energy consumption and costs.
Flexibility: EAFs can easily switch between different types of raw materials, including scrap metal, iron ore, and alloys. This flexibility allows manufacturers to adapt to changing market demands and recycle scrap materials effectively.
Environmental Benefits: EAFs emit fewer greenhouse gases and pollutants compared to traditional steelmaking methods like blast furnaces. This contributes to lower carbon emissions and improved air quality.
Lower Capital Costs: Building and maintaining EAFs tend to be more cost-effective than constructing and operating blast furnaces, which are larger and more complex facilities.
Quick Start-Up and Shutdown: EAFs can be started and stopped quickly, making them ideal for handling fluctuating production demands and reducing downtime.
Precise Temperature Control: Electric arc furnaces offer precise temperature control, which is crucial for achieving specific metallurgical properties and producing high-quality alloys.
Custom Alloy Production: EAFs allow for the production of custom alloys with precise chemical compositions, catering to the needs of various industries.
Recycling Capabilities: EAFs are excellent for recycling scrap metal, reducing the environmental impact of metal production and conserving natural resources.
Reduced Waste: The EAF process generates less waste material compared to other melting and refining methods, reducing disposal costs and environmental impact.
Lower Noise Levels: Electric arc furnaces typically produce less noise compared to some other industrial processes, creating a safer and more comfortable working environment for operators.
Improved Safety: EAFs have safety features that help prevent accidents and protect workers from exposure to extreme heat and harmful substances.
Modularity: EAFs can be designed in various sizes and configurations, allowing companies to scale their operations up or down as needed.
High Product Quality: With precise control over temperature and composition, EAFs can consistently produce high-quality metals and alloys, meeting stringent industry standards.
Reduced Lead Times: EAFs can significantly reduce lead times in metal production because of their quick start-up and operational flexibility.
Lower Maintenance Costs: Electric arc furnaces generally have lower maintenance requirements compared to some other types of furnaces, which can lead to cost savings over time.

These advantages make electric arc furnaces a preferred choice for a wide range of applications in the metallurgical and manufacturing industries, including steelmaking, alloy production, and metal recycling. Additionally, their energy efficiency and reduced environmental impact align with sustainability goals and regulatory requirements.

Disadvantages of electric arc furnace

While electric arc furnaces (EAFs) offer many advantages, they also have some disadvantages and limitations that need to be considered in industrial applications. Here are some of the key disadvantages of using electric arc furnaces:

High Electricity Consumption: EAFs require a substantial amount of electrical power to generate the electric arc and maintain high temperatures. This can result in significant electricity costs, especially during periods of high energy prices.
Initial Investment Costs: The capital cost of installing an EAF can be high, particularly for larger furnaces with advanced features and pollution control equipment. This initial investment can be a barrier for smaller companies or those with limited resources.
Limited Capacity: EAFs have a limited capacity compared to some other types of furnaces like blast furnaces. This limitation can be a constraint for companies with high production demands.
Variable Scrap Quality: When using scrap metal as a raw material, the quality and composition of the scrap can vary, which can lead to variations in the final product’s quality and composition.
Dust and Emissions: EAFs can generate dust and emissions, including particulate matter and volatile organic compounds. To address environmental concerns, additional equipment and processes may be needed for emissions control and dust collection.
Consumable Electrodes: The electrodes used in EAFs are consumable and need to be replaced periodically. This incurs additional maintenance and operating costs.
Maintenance Requirements: While EAFs generally have lower maintenance requirements compared to some other furnace types, they still require regular maintenance to ensure optimal performance and longevity.
Noise and Vibration: EAFs can produce noise and vibration during operation, which may require measures to protect workers and minimize the impact on nearby communities.
Reliability: The electrical components of EAFs, such as transformers and power supplies, can be susceptible to malfunctions or breakdowns, leading to production disruptions.
Safety Concerns: Working with high temperatures and electrical currents poses inherent safety risks. Proper safety measures and training are essential to prevent accidents.
Specialized Expertise: Operating and maintaining EAFs requires specialized knowledge and expertise, which can limit the pool of qualified personnel and increase labor costs.
Raw Material Handling: EAFs rely on a steady supply of raw materials, which must be properly sorted, prepared, and loaded into the furnace. Inconsistent or inefficient material handling can affect production efficiency.
Environmental Regulations: Meeting stringent environmental regulations, especially regarding emissions and waste management, can add complexity and cost to EAF operations.
Production Interruptions: EAFs may need to be shut down for maintenance or electrode replacement, leading to temporary production interruptions.
Size Limitations: The physical size and design of EAFs can limit their application in some industries or for specific products that require larger or differently shaped furnaces.

Despite these disadvantages, electric arc furnaces remain a valuable and widely used tool in the metallurgical and manufacturing industries, especially when their advantages, such as flexibility and environmental benefits, align with specific production requirements and objectives. Advances in technology continue to address some of these limitations over time.

blast furnace vs electric arc furnace

Here’s a comparison table between a blast furnace and an electric arc furnace (EAF) based on various key aspects:

Aspect	Blast Furnace	Electric Arc Furnace (EAF)
Primary Use	Production of primary iron from iron ore	Melting and refining of scrap metal and alloys
Raw Materials	Iron ore, coke, limestone, and additives	Scrap metal, ore, alloys, and additives
Energy Source	Coke and coal for heating	Electricity for generating electric arcs
Temperature	Extremely high temperatures (above 2,000°C)	Very high temperatures (above 3,000°C)
Environmental Impact	High greenhouse gas emissions	Lower greenhouse gas emissions
Efficiency	Lower energy efficiency	Higher energy efficiency
Flexibility	Limited flexibility in raw material use	Greater flexibility with scrap metal
Production Scale	Typically large-scale operations	Suitable for both large and small-scale operations
Start-Up Time	Longer start-up time (days)	Shorter start-up time (hours)
Continuous Operation	Often continuous operation	Easily adaptable to fluctuating demand
Quality Control	Limited control over composition	Precise control over composition and temperature
Maintenance	High maintenance due to wear and tear	Lower maintenance requirements
Initial Investment	High capital investment	Varies based on size and capacity
Recycling	Not suitable for recycling scrap metal	Ideal for recycling scrap metal
End Products	Pig iron, which requires further processing	Molten metal for various applications
Environmental Benefits	Lower air pollution, but high CO2 emissions	Lower air pollution, reduced CO2 emissions, and energy efficiency benefits

Please note that the comparison is based on general characteristics, and specific operations and results can vary depending on the design and technology used in individual blast furnaces and EAFs. The choice between these two methods depends on factors like the type of metal production, raw materials available, and environmental considerations.