Pollution Control Equipment | Use and Benefits of Cyclone Dust Collectors
As India progresses in industries and manufacturing, it also witnesses a steady increase in the pollution level. Although pollution is caused due to various reasons, one of the main contributors to pollution is industrial waste. With the hazardous consequences of industrial disposal, the best course of action for industries is to opt for pollution control equipment to minimize the harm.
The government of India has taken several steps to monitor and tackle the problem of accelerating industrial emissions like Online Continuous Emissions/Effluents Monitoring Systems (OCEMS). This monitoring system monitors and regulates the emission of particulate matter (PM), SO2 (sulfur dioxide), NOx (nitrogen oxide), CO (carbon monoxide), and fluoride. A study reveals that, on average, an Indian inhales up to 25 micrograms/cubic meter of toxic air in 24 hours, which is substantially higher than the World Health Organization’s maximum limit of 10 micrograms/cubic meter. It may cause severe damage to the lungs and the overall health with respiratory diseases, cancer, strokes, deafness, blindness, and other illnesses.
To control and maintain the level of pollution industries can avail themselves of various types of pollution control equipment. In the case of industrial steam boilers, one of them is cyclone dust collectors.
Cyclone dust collectors, as the name suggests, collect the excess dust particles from the boilers. It gained its initial recognition in the 1950s and has been serving its purpose since then with various advancements and modifications in design and structure. Cyclone dust collector uses centrifugal force instead of any specific moving parts to segregate the particulates like ash or other larger pollutants from the flue gases in the boiler. Cyclone dust collectors are classified into two types: Single Cyclone Dust Collector and Multi Cyclone Dust Collector.
Single Cyclone Dust Collector:
Single cyclone dust collector is one of the most basic and commonly used types of dust collector. It uses inertia and centrifugal force to separate dust particles from the exhausts in the boilers. Factors such as the size of particles, gas temperature, pressure, sticky dust particles, and moisture content are considered while manufacturing single cyclone dust collectors.
Functioning:
It is located before the dust filters, positioned near the vacuum pump in the system. The air starts spinning in a cyclonic motion as it pulls through the dust collector chamber towards the vacuum pump at high speed. The centrifugal force due to the high speed and cyclonic airflow steers the heavy particles and dust towards the cyclone chamber wall. As these particles hit the chamber, it loses velocity and falls in the bin or hopper placed under the cyclone dust collector.
Advantages of Single Cyclone Dust Collector:
1. Cost-effective
2. Economical and Easy to Maintain
3. Requires less footprint
4. Reduces the amount of dust and minimizes pollution
Multi Cyclone Dust Collector:
Multi Cyclone Dust Collector is the emerging and extensively preferred pollution control equipment in the industries. It uses centrifugal force, gravity settling, and inertia, forming a dual vortex to collect particulates. The efficiency of multi cyclone dust collectors depends on various factors like air temperature, moisture content, type of dust (stick, combustible, and abrasive), size of the particles, etc.
Functioning:
Multi Cyclone Dust Collector consists of numerous cyclones of small diameter that work collectively. It works by creating a downward and an inner whirling. When the gas enters the cyclonic collector, it accords with a whirling and cyclonic motion. This motion gives rise to the centrifugal force that directs the dust particles towards the walls of the collecting tubes. The particles fall at the bottom and are released from the system.
Multi Cyclone Dust Collectors are more effective pollution control equipment as compared with Single Cyclone Dust Collectors due to their small and long diameter that helps with better separation and collecting of dust.
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Advantages of Multi Cyclone Dust Collector:
- Effective Cleansing because of multiple cyclones
- Minimal Erosion and Air Pollution
- High-performance and Efficiency of Boiler
- Cost-effective and Less Maintenance
- Smooth Operation
Although cyclone dust collectors are excellent pollution control equipment that helps to optimize boiler efficiency, it is equally vital to ensure the maintenance and efficiency of dust collectors. If overlooked, it might hamper its functioning, which, in turn, would reduce the boiler efficiency and increase the harmful emissions. Some of the factors that affect cyclone dust collector efficiency are:
Diameter and Height of Cyclone:
The diameter of the cyclone must be optimal in size. While a small-sized diameter ensures greater centrifugal force and consequently higher efficiency; However, too small-sized a diameter might lower the efficiency due to the inability to collect the finer dust particles.
Air intake surface:
Since air intake is a crucial component of a dust collector, it greatly affects its efficiency. In other words, the smaller the air intake surfaces with high velocity, the greater the dust removal efficiency.
Speed of inlet wind:
The optimal range of inlet wind speed must be between 12 to 25 m/s. Speed below 12 m/s results in a drop in dust collector efficiency and higher than 25 m/s would result in increased resistance loss rather than efficiency that would resultantly increase the energy consumption.
Gas temperature:
As the temperature of gases increases, so does their viscosity. That results in a rise of centripetal force, hindering the separation and ultimately reducing the dust collector efficiency.
Rakhoh’s Range of Pollution Control Equipment:
Rakhoh Boilers are one of the leading boiler manufacturers in Pune and one of the trusted names in boiler suppliers in India. Since our inception in 1983, we have aimed for advancement and sustainability by delivering efficient industrial steam boilers and high-quality dust collectors. Rakhoh’s Trimax Type Single Cyclone Dust Collectors and Multi Cyclone Dust Collectors are efficient, reliable, and easy to maintain. We manufacture boiler accessories and pollution control equipment to ensure higher efficiency and the life cycle of boilers. Rakhoh also provides boiler-related services such as annual contract maintenance, training programs, automation and control systems, energy audit, etc.
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Negligence in Maintenance And Safety Measures in Steam Boilers
Manufacturers of Boilers focus on producing highly effective and durable boilers for the process industries. Steam Boilers play a significant role in almost every industrial sector. With the use of steam boilers, processing has become more efficient, reliable, and swift. Steam boilers are therefore unarguably one of the most important units in any processing plant. Boilers work by heating the water from burning of fuels which generate steam of the desired temperature.
Steam boilers are used in various manufacturing industries such as pharmaceuticals, chemicals, paper, textile, distilleries, etc. They are also used to generate power through turbines or engines. Therefore, the manufacturers of boilers ensure that boilers produced by them are efficient and reliable as per the requirement.
However, along with operating steam boilers, it is equally or perhaps more important to regulate and maintain their safety measures. Neglecting the precautions may result in boiler shut down, boiler explosion, and fatal accidents and injuries in the process plants and the staff. Unmaintained steam boilers can be as dangerous as an explosive bomb. Regardless of the sturdy and sophisticated quality assured by the manufacturers of boilers, it is necessary to regularly maintain and inspect them to avoid any accidents or fatalities.
Although steam boiler failures can occur due to many factors, some most commonly found negligence that brings threat to the functioning of the steam boiler are:
Low Water Level: In many of the steam boiler failures, the main cause found is that the water level was lower than what was predetermined by the manufacturers of boilers. To understand this better, let us consider a Solid fuel boiler or a Multi fuel boiler that produces steam by boiling the water by burning fuels. The furnace made of steel can withstand high temperatures because of the presence of water. At this stage, if the level of water is less than expected, the steel tubes continue to get hotter, and after a point, fail in their mechanical energy. It may result in a breakdown or some catastrophic failure or mishap.
Feed Water Quality: The quality of feedwater is an important factor to consider while injecting it into steam boilers. Poor quality of feed water may cause a breakdown in boilers. It must be noted that the use of feed water is unique in different types of boilers and manufacturing units. If the feed water contains excess sediments, it may cause interference in the process of filtration that, in turn, causes a layer of the solid sediments to form on the piping. It causes overheating in the internal tubes that ultimately leads to breakdown or explosion in the steam boilers. Such explosions cause excessive heat in the manufacturing plants, and the oxygen level is reduced tremendously, making it highly dangerous for the concerned personnel.
Fuel Combustion Explode: It is common knowledge that combustion in steam boilers takes place after fuels are burned. Therefore, it is essential to check the burner of the boiler. Manufacturers of boilers suggest that regular assessment and servicing of the boilers are necessary. Oversight in fuel-burning or faulty gas lines can lead to dangerous blasts of gas leakages.
Improper Blowdown: The process of reducing the number of unrequired solids in the boiler is possible through feedwater and blowdown. The blowdown process helps in maintaining the solid aggregation in the solid fuel boiler or multi-fuel boiler as per their requirement. This solid aggregation includes suspended solids, dissolved solids, alkaline, and silica. A high level of blowdown is required as the operation of the boiler advances. However, if the water level remains high due to improper blowdown, it may cause the formation of sediments, excess moisture because of foaming, corrosion, and poor quality of steam. At such an occurrence, the solids and silica are carried with the steam and accumulate in internal parts of the boiler like the turbine and superheater. This formation, along with the high temperature may cause instability or shut down of boilers.
Precautions to Follow for Boiler Safety:
Certain precautions can prevent incidents of explosive boilers. Regardless of the boilers being solid fuel boilers or multi-fuel boilers, manufacturers of boilers advise following some steps to maintain safety and stability in the processing industry.
1. Regular checking of the boilers and their accessories to examine any potential faults or danger
2. Inspect if there are any leakages of steam, water, or flue gases from any part of the boilers
3. Cleaning of the part that is moveable or unfixed
4. Ensure that the water is treated before feeding it to the boiler
5. Follow the safety manual provided by the manufacturer of the boiler
6. Train and Educate the operating staff about the safety precautions while using a boiler
Rakhoh boilers have successfully manufactured and installed various types of boilers to their clients over the years. We provide Solid fuel boilers, Multi fuel boilers, oil fired boilers, and so on assuring that our boilers are of top-notch quality and safety. We also provide best services with periodic boiler servicing, maintenance, repair, and upgrading in boilers. Rakhoh boilers have always placed efficiency and safety as its utmost priority.
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Major Boiler Problems and Their Solutions Suggested by Boiler Manufacturers
Boilers are of vital importance in the running of any process industry. Boiler manufacturers take utmost care while manufacturing them to ensure that they are highly efficient and durable for their respective clients. However, boiler manufacturers advise keeping a check on some commonly found problems in boilers that may prove threatening towards the efficiency of boilers.
Rakhoh Boilers design, manufacture, and install highly efficient and sturdy boilers in various processing plants and industries for over 30 years. As a leading boiler manufacturer in India, Rakhoh provides top-notch quality boilers and boiler-related services to their clients. Despite that, there are problems that industrial boilers face if the boilers are not checked or maintained regularly.
Here are 5 majorly found problems in Industrial Boiler:
Carry-Over:
When the water is not separated from the mixture of steam and water, the contaminant of the solid, liquid or gaseous fuels leaves the boiler drum along with the steam that results in carry-over. It may not seem to pose a serious threat, but it affects the steam performance of the boiler, especially in steam traps, turbine blades, and valve bodies.
Some of the reasons that cause Carry-Over are:
Drum size:
The three-element drum control level has introduced the design of smaller diameter drums. The diameter of the drum should be such that the distance between the water-steam interface and driers is appropriate to avoid carry-over.
Feedwater:
A high amount of a contaminant in feed water leads to a high level of carry-over in the boiler. Feedwater containing dissolved oxygen results in generating iron oxide, consequently releasing increased iron in boiler water and high carry-over.
Fluctuating Load:
An increase in steam demand leads to lower drum pressure that results in a phenomenon called priming. Due to priming, slugs of water are carried along with steam resulting in high carry-over.
Steam Pressure:
Low steam pressure increases the steam volume inside the boiler. It results in the steam velocity in the internals being at a lower pressure which causes hindrance in the separation of water droplets from steam, resulting in carry-over.
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Solutions to Avoid Carry-over:
- Proper Feed Water Treatment
- Ensure Water Levels are Low
- Avoid any external material leakage in the feed water of the boiler
- Seek the guidance of boiler manufacturer on boiler and feed water treatment
Corrosion:
Corrosion in boilers destroys the boiler metal due to the pitting of dissolved oxygen in the boiler water. It results in deep holes or penetrations through the metal of the boilers that may affect the overall performance of the boiler and reduces the boiler life.
Some of the main reasons for corrosion are:
Presence of Oxygen in Boiler Water:
When the water is heated, the dissolved oxygen starts to release and reacts with the iron metal of the boiler. It forms ferric oxide or Rust that leads to corrosion.
Presence of Carbon Dioxide in Water:
Similar to the presence of oxygen, corrosion results due to the carbon dioxide in the boiler water.
Negligence towards Maintenance:
One of the reasons for corrosion is neglecting regular maintenance and servicing of boilers. Corrosion, if overlooked, may cause consequences like boiler explosion.
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Solutions to Avoid Corrosion:
- Ensuring ventilation under high temperature and vacuum conditions
- Adding Sodium Sulphite or Sodium Sulphide
- Regular Checking and Maintenance by Boiler Manufacturer
Foaming:
Foaming in a boiler occurs when the steam bubbles are gathered from the generated steam rising through the water in the boiler. When left unchecked, it forms deposits in the tubes in the boiler leading to their failure. Foaming decreases the efficiency of boilers and causes fluctuations, contaminations, and scaling in the boiler.
Some of the main reasons for Foaming are:
Bubble Formation:
The formations of small bubbles on the water surface are difficult to get rid of. It leads to foaming in the boiler.
Presence of Alkalis and Oils:
The presence of chemicals such as alkalis and oils with the solid elements in the boiler water react and produce foam. It reduces the surface tension of water and increases foaming.
Lubricating Boilers:
The oiling or lubrication in boilers serves as one of the primary reasons for foaming in boilers.
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Solutions to Avoid Foaming:
- Proper treatment of water and removal of oil or alkalis from it before feeding it in the boiler
- Neutralizing the surface tension by using anti-foaming means such as castor oil
- Removal of oil traces by introducing sodium aluminates
Priming:
When the droplets of water are carried away along with steam during the steam production in the boiler, it results in the formation of ‘wet steam’. It is known as ‘Priming’ that reduces the energy efficiency and leads to deposits of salt crystals in turbines and superheaters. It reduces the lifespan of the boilers and the boiler components.
Some of the main reasons for Priming are:
Higher Water Level:
Excessive water level leads to its releasing along with steam which in turn results in high carry-over.
Steam Pressure below Boiler design:
It is essential to adjust the boiler steam pressure as per the design made by the boiler manufacturer. Lower steam pressure results in a higher level of priming.
Oily components in the boiler water:
The presence of oil in the boiler water results in foaming and the water gets released through steam.
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Solutions to Avoid Priming:
- Filtering of water before feeding it to the boiler
- Blow-down of the sediments from the boiler
- Ensuring a low level of salts in the boiler water
Scaling:
Scaling is caused by the formation of contaminated water on heat transferring surfaces of the boiler. It hampers the heat transfer. Scaling results in the higher use of fuel than is usually required to produce steam. Scaling may lead to up to a 20% decrease in the efficiency of the boiler.
The most primary reason for Scaling is:
Hard Water in Boiler:
The presence of calcium and magnesium salts (carbonates or sulfates) or higher concentration of silica as to the alkalinity of the boiler water causes scaling in the boiler.
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Solutions to Avoid Scaling:
- Blow-down operations can assist in the removal of scales that are found on the surface of the boiler.
- Chemical treatment such as Calcium Sulphate along with Ethylenediaminetetraacetic Acid aids in removing hard scales
- Brittle scales can be removed through thermal operations.
Conclusion:
It is important to maintain and upgrade your industrial boiler to ensure its proper functioning. Seek the expert advice of your boiler manufacturer to know the best methods to prevent any service disruption of the boilers. Boiler manufacturers in India as well as throughout the world suggest regular servicing and upgrading of boilers. Boiler manufacturers believe that the proper maintenance of the boilers leads to an up to 90% increase in boiler efficiency.
Rakhoh Boilers with their expertise of more than 38 years are a leading boiler manufacturer in India for industrial steam boiler and provide excellent and timely boiler services like boiler retrofit and upgrades, energy audit, steam trap assessment, plant maintenance, customer training program and much more
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Forced Draft Fans and Induced Draft Fans in Steam Boilers
As we know, combustion is a necessary process to generate steam in a boiler. Regardless of the type of fuel used (solid, liquid, gaseous), the presence of three elements: Fuel, Heat, and Air are undeniable for the proper combustion process. Boiler manufacturers use Mechanical Draught Fans to facilitate the air requirement in the boiler and to ensure an appropriate combustion process. Steam boiler mainly utilizes Forced Draft Fan (FD Fans) or Induced Draft Fans (ID Fans) in their operations.
Forced Draft Fan and Induced Draft Fan are both commonly termed as Centrifugal Fan or Centrifugal Boilers. The main difference between both the fans is that the Forced Draft Fan pushes air into the furnace for combustion while the Induced Draft Fan pulls the flue gases out of the steam boiler after the combustion process. Forced Draft Fans are found at the inlet of a boiler as they push high-pressure air in the combustion chamber, whereas Induced Draft Fans are located at the outlet of the boiler between dust collector and chimney.
Forced Draft Fans:
The primary function of Forced Draft Fans is to supply air for combustion in steam boilers. FD Fans create air pressure mechanically in the combustion chamber of a boiler.
One of the most preferred ways of accumulating more energy through combustion with solid fuels is through fluidized bed combustion. However, this process would be unsuccessful without a Forced Draft Fan. The occurrence of fluidization is possible solely due to the Forced Draft Fan as it supplies adequate pressurized air as per the weight of the bed and the quantity of fuel that aids in creating fluidization of the sand in the furnace of the boiler.
It is essential to calculate the pressure head as well as the quantity of air supplied for combustion.
In some cases, Secondary Air Fan fulfills the demand of excess air required for the process of complete combustion. Primary Air Fan and Secondary Air Fan both fall under Forced Draft Fan and are often installed together in a steam boiler. However, they both operate at varying flow levels and head generation.
Induced Draft Fans:
The primary function of Induced Draft Fans in a boiler is the suction or creating negative pressure to dispense the flue gases or air from the system.
Induced Draft Fans or ID Fans removes flue gases from the combustion chambers and creates a vacuum of negative air pressure with a blower to suck the air out of the combustion chamber. These air or flue gases are discharged from the boiler through a stack or chimney.
Induced Draft Fans ensures the regulation of pressure in the steam boiler and paves the way for the combustion process in the boiler by dispensing the flue gases.
Notwithstanding the many benefits of Induced Draft Fan in a boiler, including its capability of handling hot flue gases, they face a drawback of frequent corrosion and erosion in the steam boilers.
Difference between Forced Draft Fan and Induced Draft Fan:
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Apart from the push and pull factors in FD Fans and ID Fans, there are some noteworthy differences in these two centrifugal fans.
- Forced Draft Fans require less power whereas, Induced Draft Fans require more.
- The pressure within flue gases is somewhat more than atmospheric pressure in FD Fans while, in ID Fans, the pressure within flue gases is a bit less.
- The flow of flue gases is more uniform in the Forced Draft Fans and less uniform in Induced Draft Fans.
- Lastly, the risk of fire in case of any kind of leakages is high with Forced Draft Fans whereas, there is no danger of fire through leakages in Induced Draft Fans.
The Collateral Relation between Boilers and Centrifugal Fans:
Although it is a well-known fact that Forced Draft Fans and Induced Draft Fans work together to ensure proper combustion and thereby the overall operation of a steam boiler, the performance and load on the FD Fans and ID Fans depend on the maintenance of the boiler. In simple words, Clinker formation in the boiler mightily affects the functioning of FD and ID Fans.
Clinkers or slag consist of the non-combustible minerals and elements found in fuel that fuse and melt together to form lumps. It either falls on the floor or sticks to the wall of the boiler. When clinkers are gathered in large amount in the pass of the flue gases, it obstructs the air passage and creates back pressure. It results in the FD and ID fans working harder to maintain the expected draught pressure. Clinkers increase the FD and ID fans consumption and reduce the heat transfer area by settling on the boiler tubes.
Boiler manufacturers have noticed that the most common reason for clinker formation in the boilers are due to the usage of poor quality fuels and neglect in maintenance of the furnace. The fuel does not burn completely when the air-to-fuel ratio in the boiler is incorrect. These unburnt particles fuse with the high-temperature zones of the boiler that result in the formation of clinkers.
Rakhoh Boilers is a leading and trusted boiler manufacturer in India. With our 38+ years of expertise in manufacturing high-end and efficient boilers, we understand the needs and demands of the industry. Along with boiler manufacturing, we deliver excellent services such as Steam System Solution, Energy Audits, Boiler Automation, Annual Maintenance Contract, Customer Training Programme, and many others for our clients.
Know more about us at http:www.rakhoh.com
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Corrosion in Steam Boiler: Causes and its Solution
Steam boilers undoubtedly play a vital role in the processing units. Process industries face their shares of difficulties and hurdles while functioning. One of them is Boiler Corrosion. It takes place when the oxygen in the air or water reacts with the metal to form ‘oxides’. In simple words, corrosion is the reverting of metals into their ore form. Corrosion in the boilers occurs when the dissolved oxygen in the boiler water reacts with the metal of the boiler. Boiler Manufacturer, therefore, rightly terms corrosion as ‘Slow Poison for Steam Boilers’
Corrosion is mainly caused by complex oxide slag along with a low melting point. Low boiler water alkalinity or exposure of the metal to water containing dissolved oxygen during operating or even non-operating period causes corrosion in the steam boiler. The corrosive mechanism may expedite due to high temperature and stresses in the metal of the boiler. Oxidation occurs due to the reaction of the ferrous component of the metal with the atmospheric oxygen. This oxidation leads to the formation of ferrous oxides that form cavities and holes in the metal of the steam boiler. The formation of cavities and holes is known as ‘Pitting’ that ultimately leads to the corrosion of the metal.
Steam boilers when constantly exposed to dissolved oxygen leads to consistent removal of the ferrous hydroxide, thereby dissolving the metal completely. It will result in the formation of holes in boiler tubes, economizers, and feed water piping that may lead to leakages in the boiler and eventual breakdown. Dissolved oxygen in untreated feed water is highly corrosive to the boiler.
Although corrosion is destructive, the damage to the boiler varies. Here are the different types of corrosion and the Damages caused by them in the steam boiler.
Acidic Corrosion:
Acidic corrosion is caused due to the low pH of the makeup feed water and leads to assault on the metal surface of the boiler. Contamination in the boiler system causes feed water to become acidic. Acidic Corrosion is also caused due to chemical cleaning operations through excess exposure of metal to the cleaning agents and overheating of such solutions.
Acidic Corrosion leads to the formation of thinning or can be localized in areas of high stress.
Caustic Corrosion:
Caustic Corrosion takes place when the caustic is concentrated, leading to the dissolving of the protective magnetite layer (Fe3O4) that brings about loss of base metal and eventual failure of the boiler.
Caustic Corrosion is mainly caused due to the high pH level of boiler water and steam blanketing (poor circulation)
Crevice Corrosion:
Crevice Corrosion is the localized attack on a metal surface or the adjacent areas of the gap or crevice that adjoins two surfaces. It can be found between two metallic or between a metallic and non-metallic surface.
Crevice Corrosion damage is, in most cases, restricted to the metal within or adjacent to the joining surface.
Galvanic Corrosion:
Galvanic or Bimetallic Corrosion occurs through an electrochemical process, where two dissimilar metals are submerged in a conductive solution and electrically attached.
As a result, the copper is localized in specific tube banks that cause random pitting.
Pitting Corrosion:
Pitting Corrosion is one of the most damaging corrosion types in a boiler as it is quite difficult to detect or predict. Pitting corrosion is a localized form of corrosion that produces cavities or holes in the surface. In many cases, pits are covered by corrosion products.
That may result in the entire failure of the boiler system due to a narrow pit with a slight overall metal loss.
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Numerous reasons cause Corrosion in a steam boiler. Some of the causes are as follows:
- Exposure of the boiler metal to the boiler water containing dissolved gases
- The unbalanced pH level of the boiler water
- Presence of Oxygen or Carbon Dioxide in the boiler water
- Lack of Feedwater Treatment
- Negligent and Improper Maintaining of the Steam Boiler
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Corrosion is one of the serious problems faced in Industrial Steam Boilers and results in a great deal of loss if left unchecked. However, they can be prevented by following some solutions such as:
- Preventing Deposits by Scaling Inhibitors
- Preventing Pitting by Oxygen Inhibitors
- Controlling pH by Alkalinity
- Training your operating staff on Feed Water Treatment and preventive maintenance
- Contact your Boiler Manufacturer for regular servicing
Rakhoh manufactures highly efficient and reliable boilers for various industries. With an experienced and dedicated staff, we are one of the leading boiler manufacturers in India with our high-quality boilers and remarkably excellent services.
To know more about us, visit http://www.rakhoh.com
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