Connect with us

Process

Classifiers: Fourth generation classifiers

Published

on

Shares

The evolution of classifiers has hinged on improvement of their cutting ability, with a better sorting of fines and coarse and a lower by-pass, writes Anjani Kumar.

The continuous demand of increased strength cement by users has forced cement manufacturers to ensure cement of a higher fineness. The 33 grade has been upgraded to 53 grade or more and to do so, cement manufacturers have to either increase the fineness or reduce the residues on either # 272 or #72 mesh.

The result of increasing fineness has practically reduced the total productivity of a typical grinding system by 10 to 15per cent. The total capacity of the plant had gone down considerably, too. The increase in the cost of raw materials and energy, coupled with reduction in the productivity of the plant grinding systems calls urgently for new technology that can produce high strength cement without reducing the capacity of the existing grinding circuit.

Evolution of separators

Soon, classifiers came on the scene, converting open circuit grinding circuits into closed circuit grinding. The first generation separators were able to separate coarse from the fine but not the other way around. This was not meeting the desired requirements and so, further innovation led to the development of dynamic classifiers. The use of the separators allowed the product to be separated into fines and coarse fractions but the preciseness of separation depended on the efficiency and effectiveness of the separator.

Traditionally, the ground particles from the grinding plant are fed to the separator for segregating into fine and coarse, and the coarse is again fed back to the grinding plant for further grinding. The principle of separation depends on the use of centrifugal forces in case of first generation separators and proper balancing of drag, gravitational and centrifugal forces in case of dynamic classifiers.

The second generation dynamic classifier has a rotating plate for dispersion of the materials. Air circulation is ensured by a rotating rotor that is fixed in the upper part. The final product falls down under gravity and is recovered via in a double conical casing. An additional fan is added to the circuit to suck the gas output with the fines instead of rotating rotor, and this has further improved the separation efficiency in what is is known as the third- generation classifiers.

Development of LVT classifiers

Further development to the design of the rotor blades and guide vanes by LV Technology in Bangkok, helped in the evolution of the fourth- generation classifier with the highest separation efficiency and lowest pressure drop across the separating zone. In 2009, some more features were added by redesigning the rotor blades and the seals to improve further the classifying efficiency. Classifiers for all the applications including fly-ash were developed subsequently.

LVT classifiers are installed for various applications, at various grinding circuits, including ball mills, vertical mills, high pressure grinding roller press circuit (both in semi-finish and finish modes), vertical roller pre-grinder mills (both in semi-finish and finish modes), fly-ash.

Advantages of LVT classifiers

The LVT classifier is a fourth-generation classifier, in which separation takes place due to two opposing forces: the centrifugal force due to rotor blades rotation and the drag force due to passage of gases. The particle in equilibrium when these two forces are in balance and equal, determines the cutting diameter. By adjusting the rotor speed, the cutting diameter can be defined. The particles which are coarser than the cutting diameter undergoing higher centrifugal force than the drag force, are ejected out and fall due to gravity into the rejects grit cone. The finer particles for which the centrifugal force is lower than the drag force are attracted towards the centre and carried out by the gas.

Feeding arrangement

The feed is provided at the bottom and is kept in suspension. This type of arrangement ensures a proper and uniform distribution of material fluid in the entire cross- section of the rotor area. Another advantage of such an arrangement is it requires less space and can easily be used in vertical mills and air- swept ball mills.

LV packet type guide and rotor blades

The flow of the gas is controlled by the LV packet type guide vanes, which allows the tangential speed of the gas to be adapted to the speed of rotor blades so as to obtain only the radial speed of the rotor blades. Therefore, a drag force which is directly opposite to the centrifugal force is obtained, which reduces the wear on the blades considerably. The spacing and sizing of the blades also ensure proper homogeneity of the speed profiles upon inlet of the rotor on its periphery and height.

The configuration of the rotor blades ensures the cutting precision along with a high slope of separation. The rotor blades are designed in such a way that, regardless of the position in the passage between two blades, the cutting diameter is the same, which means the centrifugal and drag forces are the same for a given diameter of the particle. Two different shapes of rotor blades are developed and both will ensure the balancing of these two forces in order to maintain the same cut size throughout the blade length and width. Hence, the separating zone is not only limited to the rotor periphery but also extends to the entire passage between the blades.

The performance of a classifier is determined from the tromp curve which demonstrates the output for each size of particle.

The parameters are:

  • Cut size: Particle size corresponds to 50 per cent.
  • Kappa: Slope of the curve (Particle size distribution).
  • Delta (By-pass): Lowest point on the curve. (Amount of by-pass).

Conclusion

In addition to improvements in productivity, the classifier also improves the quality and ensures reduction in overall power consumption. LVT classifiers have achieved more than 85 per cent efficiency in separation of fines and they do the job with a minimum pressure drop, thus saving power on the fan. The main advantage of the classifier is improved particle size distribution, famously known as ‘psd.’. With LVT classifiers, the psd is very steep and thus even with lower fineness, achieving higher strengths is possible.

In case of raw material grinding and coal/pet coke grinding, with LVT classifiers, the fineness has reduced considerably, hence the burning has become easier and also combustion improved, ultimately improving the overall performance of the plant. More than 300 LNVT successful installations are presently in operation.

KV Anjani Kumar, General Manager, (Process & Commissioning) Email:anjani@lnvt.com LNV Technology

Continue Reading
Click to comment

Leave a Reply

Your email address will not be published. Required fields are marked *

Process

Price hikes, drop in input costs help cement industry to post positive margins: Care Ratings

Published

on

By

Shares

Region-wise,the southern region comprises 35% of the total cement capacity, followed by thenorthern, eastern, western and central region comprising 20%, 18%, 14% and 13%of the capacity, respectively.

The cement industry is expected to post positive margins on decent price hikes over the months, falling raw material prices and marked drop in overall production costs, said an analysis of Care Ratings.

Wholesale and retail prices of cement have increased 11.9% and 12.4%, respectively, in the current financial year. As whole prices have remained elevated in most of the markets in the months of FY20, against the corresponding period of the previous year.

Similarly, electricity and fuel cost have declined 11.9% during 9M FY20 due to drop in crude oil prices. Logistics costs, the biggest cost for cement industry, has also dropped 7.7% (selling and distribution) as the Railways extended the benefit of exemption from busy season surcharge. Moreover, the cost of raw materials, too, declined 5.1% given the price of limestone had fallen 11.3% in the same aforementioned period, the analysis said.

According to Care Ratings, though the overall sales revenue has increased only 1.3%, against 16% growth in the year-ago period, the overall expenditure has declined 3.2% which has benefited the industry largely given the moderation in sales.

Even though FY20 has been subdued in terms of production and demand, the fall in cost of production has still supported the cement industry by clocking in positive margins, the rating agency said.

Cement demand is closely linked to the overall economic growth, particularly the housing and infrastructure sector. The cement sector will be seeing a sharp growth in volumes mainly due to increasing demand from affordable housing and other government infrastructure projects like roads, metros, airports, irrigation.

The government’s newly introduced National Infrastructure Pipeline (NIP), with its target of becoming a $5-trillion economy by 2025, is a detailed road map focused on economic revival through infrastructure development.

The NIP covers a gamut of sectors; rural and urban infrastructure and entails investments of Rs.102 lakh crore to be undertaken by the central government, state governments and the private sector. Of the total projects of the NIP, 42% are under implementation while 19% are under development, 31% are at the conceptual stage and 8% are yet to be classified.

The sectors that will be of focus will be roads, railways, power (renewable and conventional), irrigation and urban infrastructure. These sectors together account for 79% of the proposed investments in six years to 2025. Given the government’s thrust on infrastructure creation, it is likely to benefit the cement industry going forward.

Similarly, the Pradhan Mantri Awaas Yojana, aimed at providing affordable housing, will be a strong driver to lift cement demand. Prices have started correcting Q4 FY20 onwards due to revival in demand of the commodity, the agency said in its analysis.

Industry’s sales revenue has grown at a CAGR of 7.3% during FY15-19 but has grown only 1.3% in the current financial year. Tepid demand throughout the country in the first half of the year has led to the contraction of sales revenue. Fall in the total expenditure of cement firms had aided in improving the operating profit and net profit margins of the industry (OPM was 15.2 during 9M FY19 and NPM was 3.1 during 9M FY19). Interest coverage ratio, too, has improved on an overall basis (ICR was 3.3 during 9M FY19).

According to Cement Manufacturers Association, India accounts for over 8% of the overall global installed capacity. Region-wise, the southern region comprises 35% of the total cement capacity, followed by the northern, eastern, western and central region comprising 20%, 18%, 14% and 13% of the capacity, respectively.

Installed capacity of domestic cement makers has increased at a CAGR of 4.9% during FY16-20. Manufacturers have been able to maintain a capacity utilisation rate above 65% in the past quinquennium. In the current financial year due to the prolonged rains in many parts of the country, the capacity utilisation rate has fallen from 70% during FY19 to 66% currently (YTD).

Source:moneycontrol.com

Continue Reading

Process

Wonder Cement shows journey of cement with new campaign

Published

on

By

Shares

The campaign also marks Wonder Cement being the first ever cement brand to enter the world of IGTV…

ETBrandEquity

Cement manufacturing company Wonder Cement, has announced the launch of a digital campaign ‘Har Raah Mein Wonder Hai’. The campaign has been designed specifically to run on platforms such as Instagram, Facebook and YouTube.

#HarRaahMeinWonderHai is a one-minute video, designed and conceptualised by its digital media partner Triature Digital Marketing and Technologies Pvt Ltd. The entire journey of the cement brand from leaving the factory, going through various weather conditions and witnessing the beauty of nature and wonders through the way until it reaches the destination i.e., to the consumer is very intriguing and the brand has tried to showcase the same with the film.

Sanjay Joshi, executive director, Wonder Cement, said, "Cement as a product poses a unique marketing challenge. Most consumers will build their homes once and therefore buy cement once in a lifetime. It is critical for a cement company to connect with their consumers emotionally. As a part of our communication strategy, it is our endeavor to reach out to a large audience of this country through digital. Wonder Cement always a pioneer in digital, with the launch of our IGTV campaign #HarRahMeinWonderHai, is the first brand in the cement category to venture into this space. Through this campaign, we have captured the emotional journey of a cement bag through its own perspective and depicted what it takes to lay the foundation of one’s dreams and turn them into reality."

The story begins with a family performing the bhoomi poojan of their new plot. It is the place where they are investing their life-long earnings; and planning to build a dream house for the family and children. The family believes in the tradition of having a ‘perfect shuruaat’ (perfect beginning) for their future dream house. The video later highlights the process of construction and in sequence it is emphasising the value of ‘Perfect Shuruaat’ through the eyes of a cement bag.

Tarun Singh Chauhan, management advisor and brand consultant, Wonder Cement, said, "Our objective with this campaign was to show that the cement produced at the Wonder Cement plant speaks for itself, its quality, trust and most of all perfection. The only way this was possible was to take the perspective of a cement bag and showing its journey of perfection from beginning till the end."

According to the company, the campaign also marks Wonder Cement being the first ever cement brand to enter the world of IGTV. No other brand in this category has created content specific to the platform.

Continue Reading

Process

In spite of company’s optimism, demand weakness in cement is seen in the 4% y-o-y drop in sales volume. (Reuters)

Published

on

By

Shares

Cost cuts and better realizations save? the ?day ?for ?UltraTech Cement, Updated: 27 Jan 2020, Vatsala Kamat from Live Mint

Lower cost of energy and logistics helped Ebitda per tonne rise by about 29% in Q3
Premiumization of acquired brands, synergistic?operations hold promise for future profit growth Topics

UltraTech Cement
India’s largest cement producer UltraTech Cement Ltd turned out a bittersweet show in the December quarter. A sharp drop in fuel costs and higher realizations helped drive profit growth. But the inherent demand weakness was evident in the sales volumes drop during the quarter.

Better realizations during the December quarter, in spite of the 4% year-on-year volume decline, minimized the pain. Net stand-alone revenue fell by 2.6% to ?9,981.8 crore.

But as pointed out earlier, lower costs on most fronts helped profitability. The chart alongside shows the sharp drop in energy costs led by lower petcoke prices, lower fuel consumption and higher use of green power. Logistics costs, too, fell due to lower railway freight charges and synergies from the acquired assets. These savings helped offset the increase in raw material costs.

The upshot: Q3 Ebitda (earnings before interest, tax, depreciation and amortization) of about ?990 per tonne was 29% higher from a year ago. The jump in profit on a per tonne basis was more or less along expected lines, given the increase in realizations. "Besides, the reduction in net debt by about ?2,000 crore is a key positive," said Binod Modi, analyst at Reliance Securities Ltd.

Graphic by Santosh Sharma/Mint
What also impressed analysts is the nimble-footed integration of the recently merged cement assets of Nathdwara and Century, which was a concern on the Street.

Kunal Shah, analyst (institutional equities) at Yes Securities (India) Ltd, said: "The company has proved its ability of asset integration. Century’s cement assets were ramped up to 79% capacity utilization in December, even as they operated Nathdwara generating an Ebitda of ?1,500 per tonne."

Looks like the demand weakness mirrored in weak sales during the quarter was masked by the deft integration and synergies derived from these acquired assets. This drove UltraTech’s stock up by 2.6% to ?4,643 after the Q3 results were declared on Friday.

Brand transition from Century to UltraTech, which is 55% complete, is likely to touch 80% by September 2020. A report by Jefferies India Pvt. Ltd highlights that the Ebitda per tonne for premium brands is about ?5-10 higher per bag than the average (A cement bag weighs 50kg). Of course, with competition increasing in the arena, it remains to be seen how brand premiumization in the cement industry will pan out. UltraTech Cement scores well among peers here.

However, there are road bumps ahead for the cement sector and for UltraTech. Falling gross domestic product growth, fiscal slippages and lower budgetary allocation to infrastructure sector are making industry houses jittery on growth. Although UltraTech’s management is confident that cement demand is looking up, sustainability and pricing power remains a worry for the near term.

Continue Reading

Trending News

SUBSCRIBE TO THE NEWSLETTER

 

Don't miss out on valuable insights and opportunities to connect with like minded professionals.

 


    This will close in 0 seconds