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Saturday, 11 September 2021 / Published in Uncategorized

Steam is an integral part of the manufacturing and process industries throughout the world. With the ever-increasing global consumption and developments in the manufacturing sector, steam boilers have proved to be an essential asset for high-quality manufacturing and optimal productivity. Cogeneration plants are an ideal example of generating steam and electricity for saving resources and releasing less emission. It uses external mechanical energy to convert into electrical energy. Steam generated in steam boilers produces electricity through a turbine. Therefore, steam is an important factor in the processing operations as well as for power generation.

Applications of Steam in Processing Plants:

Steam boilers generate steam for multiple purposes such as heating, drying, sterilizing, power generation, etc. Therefore, steam plays a crucial role in the process operations and for producing electricity. Here are some of the commonly found applications of the steam

Steam for Heating:

Process heating is one of the major applications of steam. Various factors such as high efficiency, reliability, cost-effectiveness, and ease of using make steam the preferred heating medium over other alternatives. Steam is used for either direct heating or indirect heating.

Direct Heating:
In direct heating, the steam is directly subjected to the product that needs to be heated. Precision is required to ensure uniform heating and that the steam does not exit the steam boiler without heating the products. Pharmaceuticals and food processing are prime examples that utilize steam for direct heating.

Indirect Heating:
Indirect heating, as the name suggests, uses steam to heat the products without any direct contact. Indirect heating takes place with the help of various heating equipment such as heat exchangers, cookers, jacketed vessels, etc.

Steam for Atomization:

Atomization refers to breaking the fuels into tiny particles. In a steam boiler, atomization takes place in burners. Steam is utilized for atomizing the fuel to ensure a larger surface area that results in effective combustion. Atomization also leads to minimal soot formation and acceleration in overall efficiency.

Steam for Drying:

Steam is also used to dry and eliminate the moisture content in the products. Generally, hot air is used for drying purposes. However, steam is a better alternative as compared to hot air due to being cost-effective, easy to control, and safe to use. Additionally, steam assures enhanced product quality and finishing

Steam for Power Generation:

Steam is used to generate power and produce electricity with power plants that work with Rankine Cycle. It generates superheated steam and is transported to the steam turbine. The steam drives a turbine to generate electricity. The utilized steam is converted into water, and the water is fed again into the boiler system for steam generation.
Superheated steam is ideal for power generation because the temperature and pressure of steam at the inlet and outlet of the turbine directly impact the efficiency of the power plants.

Steam for Sterilization and Disinfection:

Processing and Manufacturing industries follow standard guidelines to ensure a clean and safe work environment. Sterilization and Disinfection are crucial to ensure that the products, equipment, and the process plants.
Industries such as pharmaceutical, food processing, chemicals, distilleries, etc. ensure proper sterilization with high-temperature steam for process plants and equipment to maintain the quality of the products.

Types of Steam:

The commonly used forms of steam in processing and manufacturing industries are as follows,

Saturated Steam:

Steam at its boiling point is known as saturated steam. The most common example is steam at atmospheric pressure, at which point the saturated steam would be at 212°F (100°C). It is the most commonly used steam, especially in the pharmaceutical sector.

Superheated Steam:

As the name suggests, superheated steam has a higher temperature than its boiling point at a given pressure. Superheated steam would be hotter than 100°C but remain at the same atmospheric pressure.

Dry Steam:

Dry steam is completely in a vapor state without any liquid in it. Superheated steam is dry as any liquid is promptly heated. Saturated steam is generally dry and requires an effective steam trap to eliminate the water before utilizing the steam.

Wet Steam:

Wet steam, also known as unsaturated steam consists of water and vapor. Wet steam is unable for effective heat transfer as it has already lost its heat of vaporization.

Advantages of Steam:

Energy Holding Capacity:
As the water is heated in a steam boiler for generating steam, it absorbs energy. Steam has five or six times the energy holding capacity, which is easy to transport for direct or indirect heating purposes in process operations.

Safe to Use:
Steam is environmentally friendly and non-hazardous

Easy to Control:
The energy carried by steam can be easily monitored by controlling the temperature and pressure

Easy to Transfer:
Steam has high heat transfer properties, and it requires less heat transfer area that ensures hassle-free transfer

Serves Multi Purposes:
Steam is an ideal choice for heating, drying, and sterilizing that are performed in the manufacturing sector.

With 3000+ installations in 26 countries for 20 process industries, Rakhoh Boilers are leading steam boiler manufacturers in India and worldwide. With extensive experience and knowledge in steam boilers and thermal solutions, we are also considered one of the best boiler service providers.

Friday, 03 September 2021 / Published in Uncategorized

Boiler feedwater is a crucial component for generating steam in manufacturing and processing plants. When water is heated by burning the fuels, it results in steam generation, which is utilized for various operations. Therefore, it is important to ensure that the water used for the process is properly treated and does not contain any contaminants that may negatively impact the steam quality and boiler performance. Poor quality of feedwater leads to various issues in boilers such as corrosion, scaling, foaming, erosion, and water carryover.

An Introduction to Water Carryover in Boilers:

Water carryover in steam boilers occurs when the steam exiting from the boiler is contaminated with undissolved solids or liquid and vaporous content. Carryover in steam boilers is caused due to incomplete separation of water from the steam and may cause problems like corrosion and water hammer. In general cases, boiler water containing impurities passes to the steam system along with steam. It can also cause the formation of deposits on valves, superheaters, turbines, and heat exchangers. Significant deposits reduce heat transfer and turbine efficiency. Water carryover must be prevented at the earliest opportunity. If left unchecked, it causes a loss of efficiency due to wet steam.

Causes of Water Carryover:

Causes of water carryover are categorized into two types, i.e., mechanical causes and chemical causes. They are further classified as the following:

Mechanical Causes of Water Carryover:

Fluctuating Load:

With the fluctuations in boiler load, the possibility of water carryover increases. As the steam demand increases, the steam pressure reduces. It leads to the sudden expansion of drum water known as priming. Priming, in turn, results in slugs of water being carried with the steam that leads to carryover.

Operating Pressure:

Steam boiler, when operated at a lower pressure than its design pressure, causes carryover. As the steam pressure decreases, the specific volume of steam increases. It would lead to higher steam velocity in drum intervals at lower pressure. That hinders the separation of water droplets from steam, consequently leading to water carryover.

Size of the Drum:

The size of the drum is an important factor for carryover. The steam boilers are designed as per the steam demand. The design of small-diameter drums is enabled with three-element drum level control. The drum internals include cyclone type separators, baffle plates, screen driers, and perforated boxes. The diameter should ensure sufficient distance between the water-steam interface and driers to prevent water carryover.

Arrangement of Drum Internals:

Although there is no specific or standard procedure to arrange the drum internals, the configuration of steam boilers requires variation in drum internals arrangement. Inappropriate drum internal arrangement can be a major cause of carryover.

Erecting of Drum Internals:

Despite every care taken by the boiler manufacturer, erecting a steam boiler at the site may bring difficulties. The drum internals may fail because of corrosion due to low water quality that may lead to carryover.

High Water Level:

While the steam boilers are operating, it must be ensured that all the tripping in the boiler is properly functioning. The boiler manufacturer determines the operating level, alarm level, low water level, and high water level. The low water level impacts the circulation, and the high water level impacts the steam purity. Therefore, the chances of carryover are more with high water levels.

Improper Blowdown:
Continuous blowdown is an ideal method of maintaining the boiler water chemistry. Improper blowdown increases the Total Dissolved Solids (TDS) in a steam boiler, consequently resulting in high water carryover.

Chemical Causes of Water Carryover:

Feedwater Chemistry:

The feedwater chemistry must fulfill certain requirements suggested by the boiler manufacturer before feeding it to the steam boiler. Feedwater containing oils or organic matter leads to foaming that eventually results in water carryover. Additionally, feedwater with dissolved iron would lead to foaming as well.

High Total Dissolved Solids (TDS):

Boiler water with high TDS results in increasing the carryover of solids. For reducing the carryover, it is necessary to bring down the TDS level by eliminating the NaOH in the boiler water through coordinated phosphate control. High alkalinity and suspended solids in boiler water increase carryover.

Excess Chemical Treatment:

Water treatment is essential to minimize the possibility of water carryover. However, excess or improper chemical dosage while treating the water disturbs the boiler water chemistry, causing water carryover.

Prevention of Water Carryover in Boilers:

There are various ways to prevent water carryover such as,

  • Effective steam separators like baffles, centrifugal separators, mesh demisters, or screens
  • Monitor the steam quality by testing the Total Dissolved Solids, Alkalinity, Silica, and Organic Contamination
  • Increasing Boiler Blowdown
  • Utilizing Boiler water antifoam chemicals
  • Seek the guidance of boiler manufacturer in extreme cases

Rakhoh Boilers, with their extensive knowledge and experience in boiler manufacturing and thermal solutions, understand the problems faced by the processing plants and offer comprehensive solutions with their world-class manufacturing of steam boilers and excellent boiler services in over 26 countries worldwide.
To explore our products and services, visit www.rakhoh.com

Thursday, 02 September 2021 / Published in Uncategorized

Rice is a staple food and the second most important crop in the world. India ranks second after China and accounts for 21% of the world’s total rice consumption, and is one of the leading producers of white and brown rice globally. The Rice industry plays a significant role in the national economy by contributing to 25% of the global market share in rice exportation. In the year 2020-21, India has witnessed tremendous growth in rice exportation (non-basmati) by 132% and globally exporting rice worth 30,277 crores. India is a leading nation in supplying basmati rice globally with a 24% market share.

History of Rice Mills in India:

Rice mills are one of the ancient and largest agro-processing industries in India. The significance of the agro-processing sector first came into light in 1870 after the famine in Bengal. However, it witnessed rapid growth by the 1980s during the Green Revolution that stressed the importance of agricultural production and management. It resulted in the development of the agro-processing industry that was led by rice mills and followed by wheat milling, milk and dairy products, and so on.

In 1976, an amendment to the Rice Mill Industry Regulation Provision implemented modernization of the single-huller mills by including centrifugal de-huskers, separators, and paddy cleaners.

Types of Rice Mills and their Modernization:

Generally, most of the rice mills in India are traditional, huller-type process units. Although modernized rice mills are highly efficient, it requires considerable capital investment to begin with. However, small modern rice mills are gradually developing that are efficient and cost-effective. Other types of rice mills commonly found are sheller mills and huller-cum-sheller mills.

Process Stages in Rice Industry:

Milling is considered one of the most vital processing operations once the rice production is accomplished as it separates hulls and barns from the paddy grains to produce polished rice. Rice is the primary product obtained from paddy, which is further processed to derive secondary products. Apart from milling, the process operations in the rice industry include:

  • Pre-cleaning
  • Destoning
  • Parboiling
  • Husking
  • Paddy Separation Whitening
  • Polishing
  • Grading
  • Blending
  • Weighing and Packaging

Role of Boilers in Rice Mills:

Steam is essential in various process operations in the rice industry. Therefore, boilers for rice mills must be efficient, reliable, and of sturdy quality to ensure seamless productivity. Boilers in a rice mill are required for various operations such as parboiling, paddy separation whitening, and packaging. Boilers in rice mills are also utilized for power generation.

The parboiling process, for example, is a hydrothermal treatment that involves soaking paddy in water and later steamed to ensure that the rice gets harder and retains as much oil content in the bran. Parboiling is performed through various methods such as single steaming, double steaming, hot water soaking, and steaming. Traditional rice mills usually adopt single steaming or double steaming methods for parboiling, whereas modern mills prefer hot water soaking, followed by drying the paddy in mechanical driers.

Rakhoh Boilers are one of the renowned names as leading boiler manufacturers in many rice mills in India. Rakhoh is the preferred choice among many process industries, including Rice Mills, with a wide range of efficient and reliable steam boilers. Our Huskon model is ideal for mills that utilize rice husk or coffee husk as fuel with an automated fuel feeding system and special ferrules to prevent husk ash in smoke tubes. It is equipped with Air Pre Heater, Water Pre Heater, and Multi Cyclone Dust Collector to enhance efficiency and productivity.

Boilers in rice mills are also essential for the whitening of rice and its packaging operations as well as, for the further process of rice products.

Factors to consider while selecting a boiler for rice mills:

  • Boiler Capacity and Heating Load
  • Pressure and Temperature Load of the Boiler
  • High Thermal Efficiency
  • Effective Combustion and Low Emission

By-product in Rice Industries:

Brown Rice:

Brown rice extracted from organically grown paddy has more market and nutritional value. Brown rice needs to be milled in a rubber roll sheller to remove the husk and paddy separation.

Puffed Rice:

Puffed rice is obtained by promptly immersing the sand roasted paddy in water, draining of water, drying, and milling. The polished rice is introduced with salt solution, sugar, soda salt, and puffed in the sand medium.

Flaked Rice:

Flaked rice is produced by roasting soaked paddy and flaked in edge runner or roller flakes.

Broken Rice:

From a nutritional perspective, broken rice is the same as whole rice but with a low market cost. Therefore, broken rice or its flour is utilized for preparing dishes made of rice.

Rice Bran Oil:

Rice bran oil is gaining popularity in India as a healthy alternative for edible oil. Compared to the traditional edible oil, it is more economical as it absorbs 20% to 25% less oil.

Rice Husk:

Rice husk contains 50% cellulose, 20% silica, and 30% lignin, making it an excellent industrial fuel. India produces approximately 90 to 120 million tons of rice paddy annually.

Challenges faced in Rice Industry:

  • Out Turn Ratio
  • Milling Charges
  • Minimum Support Price
  • Lack of Infrastructural Facilities
  • Lack of Advanced Technological Equipment
Wednesday, 01 September 2021 / Published in Uncategorized

Edible Oil is indispensable for cooking purposes all over the world, especially in Indian kitchens. Oilseed production in India is not extensive, and it imports a significant amount of oil from other countries. Some of the Indian states that contribute towards oilseed production are Madhya Pradesh (27%), Rajasthan (20%), Maharashtra (16%), and Gujarat (15%) and account for 80% of total oilseed production in India. Palm oil is the most consumed oil in India, followed by soybean oil that sums up to 65% to 75% of total consumption. The process operation in edible oil refineries includes extraction of oil from oilseeds through an oil mill or chemical extraction by solvent. The oil extracted is later purified, refined, and if required, chemically altered.

The utilization of Oilseeds is classified into two groups:

1. Crushing Oilseeds into Vegetable Oil

2. Edible Oil processing is further classified into two categories:

  • Food Processing: It is used as an ingredient in many food items, sauces, and spreads
  • Confectionery: It is used as toppings to bakery products and confectionery for improved taste and appearance

Process Stages in Edible Oil Refinery:

Edible oil processing is crucial that requires precision and high-quality standards to ensure its suitability for consumption. Negligence in processing operations may lead to mishaps in the refineries or health issues with the consumer. It would result in the tarnishing of the company’s reputation. Therefore, edible oil refineries follow the standard process that involves ensuring the oil is flavorless, odorless, changes in color and crystal, and molecular structure rearrangement. The edible oil process is categorized into five stages. Let us have a look at it in detail.

Degumming:

Degumming is the first stage in processing oil that involves removing impurities such as phosphatides, also known as gums. The edible oil extracted from sunflower seed, rapeseeds, and soybean consists of phosphatides that need to be removed during the initial stage of oil refining. Due to its emulsifying properties, the degumming stage is essential to prevent the decomposing or darkening of the oil.

Neutralization:

The neutralization process, also known as alkali refining, involves the removal of fatty acids by using an alkali such as caustic soda. As the caustic soda comes in contact with fatty acids, it forms soap stocks that get settled at the bottom of the tank which, is later removed.

Bleaching:

The bleaching process is essential for color removal from the oil. The process destroys contaminants that may have a negative impact on the performance of triacylglycerol present in the edible oil. The bleaching process mixes edible oil with clay absorbent that removes color and decreases the content of residual soap, oxidation properties, gums, chlorophyll, and trace metals. The mixing of absorbents is followed by filtration and a chemical reaction that takes place in bleaching. The bleaching process depends on multiple factors such as temperature, vacuum, moisture, and contact time.

Deodorization:

The Deodorization stage involves processing oil through high-temperature and high-vacuum steam to dispense the oil from odorous and volatile components. The deodorization process is vital for removing flavors and any remaining fatty acids from the oil.

Winterization:

The final stage in edible oil processing is winterization, also known as the dewaxing of edible oil. It is a thermo-mechanical process that includes the crystallization of solid particles in edible oil under determined climatic conditions followed by mechanical separation of the crystals. The edible oil in this process is mixed with a crystallization agent and later processed through a static mixer. For crystallization to take place, the mixture is cooled in an exchanger and then filtered. The winterization process is performed for cotton and sunflower seed oil.

Role of Steam Boilers in Edible Oil Refineries:

Boilers in edible oil refineries are crucial for many process operations, especially deodorization, to ensure complete removal of components such as color, odor, and moisture that would influence the appearance, smell, and taste of the final product. Edible oil is extracted from crude by the process of deodorization through steam distillation.

Steam boilers in edible oil refineries enable the steam vacuum distillation with high-pressure steam for heating the oil to a determined temperature for removing the impurities and cooling it to regain the characteristics of the oil. Economizer helps boilers in oil refineries by extracting heat from the process to save energy.

Rakhoh Boilers have been manufacturing highly efficient and reliable steam boilers for more than 20 process industries in over 26 countries worldwide. With our extensive knowledge of thermal solutions, we are one of the trusted names as boiler manufacturers. We offer a wide range of solid fuel boilers, oil and gas fired boilers, waste heat recovery boilers, and thermic fluid heaters as per the client’s demand and requirements.

Know more about our products and services on www.rakhoh.com

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