Process

Energy Efficient Cement Grinding

Published

10 years ago

September 30, 2014

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Cement manufacturing is one of the most energy intensive activities, which typically consumes around 100-110 kwh/t of cement produced. Dr Pandey elaborates on how energy can be saved during the comminution and pyro-processing of cement.

Comminution/grinding and pyro-processing are the two major operations in the cement process with energy consumption share of around 60 and 40 per cent respectively. Comminution of bulk solids, especially in the micron size class, is the least energy efficient operation among these two, having efficiencies of not more than 8-9 per cent. Rest of the energy is largely consumed unproductively in friction, noise, heat, etc. Therefore, any improvement in the practice of comminution would be a desirable step in improving process economics because of its role in deciding cost of breakage of raw materials/intermediates in the final product economics. Clinker grinding in its most advanced state today is dominated by any of the three types of milling systems namely close circuit ball mills, roll press systems and vertical roller mills. Let us look at some other grinding technologies, which are likely to become relevant in cement manufacturing in near future.

The basic reason behind large energy consumption in size reduction is that the particle must be stressed heavily before any substantial breakage occurs. This stress is mostly stored as an elastic energy in cracks/flaws in the particle and is lost when it fractures. As particles become smaller (typically around few hundred microns), the probability of flaws in them decreases and their strength increases. Hence, for efficient grinding of very small particles, higher applied forces and relatively high probabilities for successful application of the stress on the particles are required. Such high probabilities do not exist in the conventional ball mills as they use comparatively large grinding media. As particle size decreases, grinding media size also has to decrease for efficient grinding to take place. Further, as grinding media size decreases, media velocity has to increase to generate sufficient energy for particle breakage.

Future technology for cement milling:
These pre-conditions of efficient grinding are satisfied by stirred media mills, which can achieve very high media velocities and energy densities (300 kW/m3 of mill volume) by stirring the media at higher rates (~25 m/s tip speed). As a consequence, these mills offer significant reductions in specific energy consumption compared to conventional tumbling mills. As a result, they are likely to get increased attention in cement manufacturing due to the need of reducing energy consumption for grinding. Additionally, inter-particle comminution using high pressure compression technique is one more way of effectively reducing energy wastage. Therefore, any machine working on principle of roll press with fewer problems related to wear, maintenance, etc. is also likely to be more useful in cement grinding. There are a number of manufacturers, who supply these types of energy efficient milling systems. Following are some of the major suppliers of the technology.

Stirred Media milling:
Tower mills made by Kutoba Tower Mill Corporation, Japan are low speed vertical stirred media mills, which commonly use steel balls as grinding media. Vertimill is yet another variant of the class being manufactured by Metso minerals, Australia. The Tower and Vertimill consist of an internal screw flight agitator driven by a motor, a stationary vertical grinding cylinder, a settling classifier and a pebble port which is used to remove the grinding media. The agitators used are ?double start? helical screw configuration wound around a central shaft. ?Double start? refers to two screw flights being wrapped around the same shaft to increase the screw density. The ball movement and resultant grinding action within the mill are the direct result of the rotating and lifting action generated by this agitator. According to reported literature, there are over 220 Vertimill (having capacities in the range of 50-160 tph) and more than 250 tower mill installations worldwide.

Yet another variant of stirred media mills is MaxxMill made by Maschinenfabrik Gustav Eirich, Germany. Its main components are the rotating grinding chamber, one or more agitator(s), and the stationary material deflector with integrated feed pipe. Each agitator is positioned eccentrically relative to the centre of the grinding chamber. Depending on the comminution task, the agitator may rotate in the same or opposite direction as the chamber. The grinding chamber is filled with grinding media of 2-10 mm up to a volume of max. 90 per cent (bulk volume). The MaxxMill operates continuously in dry grinding processes. Together with an air stream acting as a carrier, the material to be ground is fed through the eccentrically positioned feed pipe, entering the machine at the chamber bottom. The rotation of the vessel causes the material to be drawn into the grinding chamber where it is mixed with the grinding media. In the chamber, the grinding effect is produced by the energy input via the agitator, the variable compression of the grinding ball filling in the agitator area, the compressive stress close to the bottom, and the generation of shearing forces in front of the material deflector. The comminuted product is extracted continuously from the top of the ball layer by means of an extraction pipe with a large cross section installed in the upper part of the machine, where the grinding media, due to the gravitational force, are prevented from being extracted.

Eccentric vibration mills:
In this class of energy efficient comminution, utilising vibration mechanism (which is being developed by Siebtechnik GmbH, Germany in collaboration with TU Clausthal, Germany), the mill provides elliptical, circular and linear vibrations unlike conventional vibration mills with only circular vibrations. The major technological advance of this system consists of amplitudes of vibration of up to 20 mm (normally 12 mm maximum), leading to a high degree of intensification of the impact forces among the grinding media balls or rods part from increased throughputs.

Inter-particle high pressure comminution:
In this class of grinding Horomill (Horizontal roller mill), made by FCB, France and Fratelli Buzzi S.p.A, Italy, is expected to contribute significantly in coming years. It is based on the technique of compressed bed comminution at much lower applied pressures as compared to roll press systems. The system is reported to have energy saving potential of 40-50 per cent and 20-25 per cent as compared to the ball mills and vertical roller mills respectively. In Horomills, a cylindrical shell with horizontal axis is rotated above the critical speed by means of a unit gear, pinion, reducer and engine. A roller laid out in the shell ensures the grinding. The material to be ground, centrifuged, undergoes a multiple and controlled compression between the roller and the grinding track of the shell. The system uses proven components of the ball mill, by the use of a shell supported on hydrodynamic shoes and of a girth gear drive on one hand and components close to the principle of the roller press, such as rollers and bearings but operating with moderate pressures (four to five times less than the one used with roll presses), on the other hand. Horomills with capacities up to 280tph are reportedly installed in various cement manufacturing locations worldwide.

Process

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

Published

3 years ago

October 21, 2021

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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

Process

Wonder Cement shows journey of cement with new campaign

Published

3 years ago

October 21, 2021

admin

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

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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.

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

3 years ago

October 21, 2021

admin

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.