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Cement industry is giving a major thrust to energy-saving projects

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Dr Hitesh Sukhwal, Deputy General Manager – Environment, Udaipur Cement Works, discusses how the highly energy-intensive nature of cement production can be changed with the use of automation and optimising processes.

What is the energy consumption in one cycle of cement manufacturing process? Which process is the most energy intensive?
Cement manufacturing is a highly energy intensive process. It requires a large number of resources for making availability from raw material to finished goods. The cement manufacturing process can be divided into three major processes viz. raw material processing, clinkerisation and finish grinding processing (cement production – finished goods). Based on the water content in raw materials, the cement manufacturing process further can be divided into four categories like dry, semi-dry, semi-wet and wet process. Since cement production requires complete evaporation from the raw material, a higher percentage of water content will require a more energy intensive process.

In general, energy consumption in the cement industry is fulfilled from electrical energy and thermal energy from different kinds of fuels. Over 90 per cent of the energy consumed from fuels in the production of clinker. On the other hand, electrical energy is used for processing the raw material, burning the clinker, grinding of finished product, packaging etc. Maximum utilisation of electrical energy in cement manufacturing process is in grinding.

Based on the manufacturing process whether dry, semi dry, wet process, energy consumed accordingly. Today with few exceptions, almost all cement industries have adopted the dry manufacturing process, which is a more efficient process for energy consumption in comparison to wet processes.

What are the sources of energy used for cement manufacturing in your organisation?
Udaipur Cement Works Limited (UCWL) has an integrated cement plant with an installed production capacity of 2.2 million tonnes per annum (MTPA).

Our company is committed towards sustainable business growth by adopting the latest state-of-theart technology based and resource efficient equipment in its manufacturing process. The company has ISO certification for Environment (14001), Occupational Health and Safety (45001), Energy (50001) and Quality Management System (9001). Company has also inventoried its carbon and water footprint as per ISO 14064 and ISO 14046.

With in-house innovations, our company has done various energy saving projects and reduced energy consumption. UCWL has a 6.0 MW waste heat recovery-based power plant as a green power source.

During fiscal 2021-22, UCWL increased its solar power generation capacity by 4.35 MW, in addition to the existing 10.1 MW. Further, our unit is going to install 10 MW WHRS with the ongoing Line 2 project. Today, the company sourced about 45 per cent of its energy from green power sources in the total power mix i.e., Solar and WHRS. We are also utilising alternative fuel as a source of thermal energy.

How does automation and technology help in optimising the use of energy in cement plants?
Cement industry is highly energy intensive. We are living in a new era of digitalisation. Nowadays, everything we want on our one hand about operational reports, monitoring, checking data and verification and of course the health of machines in day-to-day operation. It is only possible by adopting technology innovations and automation by the industry. Every cement industry is improving productivity to make up for the upcoming demand in consideration with cost viability. An improvement in a production technology is the best way for reduction in energy consumption. The latest digital technology is a key element for the continuous improvement for operational excellence. Advanced HMI/SCADA empowers optimal supervision and control of all operational sections in cement plants. These control devices can be linked up with equipment and enabled to get trends of machine, alarms etc., which can further be used as a reporting tool for desktop meeting and decision making. To become energy efficient is a need of the hour for the cement industry. There are technology solutions with which the industry can reduce and optimise the use of energy in cement plant such as by installation of sensors in various operational units, automated real time weighing system, smart metering for accurate measurement and monitoring, real time data acquisition system, online process sensors for getting operational report, advanced process control system, remote access for online monitoring etc. For example, Variable Frequency Drive (VFD) is the best example in the cement industry to cut down energy consumption in various operations.

What are the major challenges your organisation faces in managing the energy needs of the cement manufacturing process? As I said, our unit is meeting out more than 45 per cent of its total electrical energy requirement from the green renewable sources viz. solar and WHRS. Remaining electrical energy requirements are being fulfilled from the grid. Sometimes fluctuation in power supply from the grid disturbs the main operation in cement plants. We are working upon improving and getting rid of this issue for the plant.

Regarding thermal energy concern, dynamic fuel prices affected the input production cost in cement manufacturing. Tell us about the compliance and standards followed by you to maintain energy use and efficiency in the organisation? Our manufacturing unit is covered under the Perform, Achieve and Trade (PAT) scheme under Bureau of Energy Efficiency (BEE) by the Ministry of Power, Government of India for reducing its specific energy consumption year on year.

The company is also certified with ISO 50001 for Energy Management.

How often are audits done to ensure optimum use of energy? What is the suggested duration for the same?
As I stated earlier, our company is covered under the PAT scheme. We are an ISO 50001 certified company under energy management. We have a dedicated resource under the designation of ‘energy manager,’ who is qualified to keep a check on the energy consumption of the plant and continuously optimise the same.

A periodic energy audit (once in three years) as per EC Act is done. Half yearly internal audits and external audits once a year are performed under energy management. Moreover, power monitoring reports are discussed on an everyday basis during the desktop production meeting.

How does energy conservation impact the profitability of the organisation? What impact does it have on the productivity of the process?
The cost of cement production is governed by so many factors like availability of raw material, quality of raw material and off course fuel for thermal energy and electrical energy. As we know, the cement industry is highly energy intensive. The cost of energy as a part of the total production in the cement industry is significant. To improve the bottom line, the cement industry needs to focus on energy conservation and effective management. A huge amount of thermal energy is consumed in clinkerisation whereas high electrical energy is consumed in the grinding section.

The cost of energy per unit directly impacts the profitability of the organisation. The dynamic price of fuel and cost of electrical energy production played an important role in the cement making cost.

What are your efforts towards carbon emission reduction?
In view of climate change and the COP 26 commitments by the nation, today the UCWL meets more than 45 per cent of its total electricity requirement from the green renewable sources like solar and WHRS. The company has increased its capacity by installation of 4.5 MW solar power generation in addition to the 10.1 MW existing solar power capacity.

In addition to the existing 6 MW WHRS, we are going to increase WHRS capacity by installation of an additional 10 MW WHRS. By using green renewable power sources, we will be able to reduce a significant amount of carbon emission from our operation. We are also utilising alternative fuel or industrial waste derived fuel in our cement manufacturing process, which is also an impact on carbon emission reduction.

In what areas can cement manufacturers drastically reduce their energy consumption and how?
The cement industry is giving major thrust on energy saving projects. With the help of process optimisation, adoption of technological innovation, digitalisation of process control system, manufacturing of blended cement, AFR, retrofitting of old machineries/ motors, replacement of ball mills with vertical raw mill, efficient pollution control equipment etc. cement manufacturers can reduce energy consumption, cost of production and reduction in carbon emission.

Vertical roller mill is more energy efficient and requires less space as compared to a ball mill. By installing a roller press (for size reduction) before the mill can improve grinding quality. The significant changes in technology in the grinding section will reduce electrical energy requirement (specific energy consumption). Increase in blended percentage in cement making decreases specific energy consumption.

What kind of innovations in the area of energy consumption do you wish to see in the cement industry?
In the near future, sustainability and digitisation will be two key areas for cement business development.

Every technology innovation in terms of automation and digitisation will lead the cement industry in the area of energy consumption, carbon emission reduction and profitability.

Artificial intelligence and Industry 5.0 can provide new innovations in energy reduction. Innovation in plant machinery, robotics and manufacturing of eco green cement will make sense for cement sustainability.

Concrete

Precast use of concrete promotes sustainability

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Vijay Shah, Managing Partner, India Precast, advocates the use of precast concrete as he puts forth details about its manufacturing, uses and methods while emphasising the sustainability of the product.

Explain the process of casting concrete in shapes and what is the grade of concrete used for making these shapes?
Precast casting concrete elements are manufactured with the required steel reinforcement either in formwork, moulds or on steel plates with side shuttering etc. The concrete cast is made at a different location and is then transported to the site. Precast elements are made of minimum M20 to M50 grade of concrete.

What is the difference between precast and cast in-situ as uses of concrete?

  • The use of concrete in the precast method and the cast in-situ method differs widely based on many factors.
  • Precast concrete shapes are cast at a different location and are then transported to the site where construction work takes place while with the cast in-situ process, concrete is poured on-site.
  • Curing of precast concrete is fast as it takes place under ideal and controlled conditions while the cast in-situ concrete takes relatively longer to get cured but can be easily used for two-way structural systems.
  • For the precast concrete, the process is easy to do and is repeatable as the same moulds or framework can be used. This increases the value of construction and derives more value
  • while cast in-situ adapts building shapes and post tensioning.
  • The work and rework in the usage of precast shapes is less, thus, reduces cost at the site
  • while with the cast in-situ method there is a requirement of space allotment for concrete mix and necessary add-ins, that is added cost for the construction job.

Tell us about prestressed and reinforced concrete.
Prestressed concrete is a combination of high strength concrete and tensioned steel strands. This combination makes a strong structural unit that is useful in building roof slabs, bridge girders etc. Reinforced concrete is manufactured from a combination of high strength concrete and normal reinforcement bars.

Tell us more about the precast elements manufactured, their shapes and sizes.
Precast is one of the best ways to rapidly build industrial buildings, commercial buildings, affordable housing, mass, EWS, LIG housing, schools, hospitals, public buildings, agriculture railways, stadiums, sport centres, parking, bridges, airports etc. They have a higher productivity and quality set at industry level.
Various types of precast elements manufactures are:

  • Solid load bearing floor slabs, load bearing walls, facades, sandwich wall panels and cladding panels
  • Floor and roof slabs are made from prestressed load bearing hollow core concrete slab and ribbed slabs. They are also made from half floor slab or semi-finished floor slab with a lattice girder
  • Precast stair cases, balcony, toilet pods, lift shafts, water tanks
  • Prestressed lintel, frames, beams, columns and double-tee beams
  • Internal partition walls are made with light-weight hollow core wall panels instead of AAC blocks or bricks
  • Boundary walls, fencing poles, U-drainage or trenches, box culvert etc.

What is hollowcore concrete flooring and what is its lifespan?
Hollowcore slabs are precast, prestressed concrete elements that are generally used for flooring. Some of the advantages of using these flooring are longer lifespans and no propping, flexibility in designs, faster construction, lightweight structures, fire resistant structures, high load capacities and units manufactured specific to the project.
The maximum span of hollowcore floors will depend on the floor depth and the specific loadings imposed on the floor.

What are the quality standards followed while making precast shapes for any project?
Quality control is a very important aspect in the process of making precast concrete shapes. It is imperative to make precast shapes as per the exact requirement provided by the engineers and the construction party. To maintain the quality of product from our end,

  • We ensure there are quality control systems and procedures in place along with a quality assurance plan. Our programme consists of tests, trials, and general procedures for acceptance.
  • There is a laboratory and related facilities, which are required for the selection and control of the quality of materials and workmanship. The central quality laboratory is used for various quality control tests like cube test, workability test, slump test, sieve analysis etc. The materials used for making the final precast shapes also has to be shared for testing to various third-party laboratories with an advance intimation.
  • All the necessary tests are carried out in respective batching plants or sites depending on the use of concrete at our facility.
  • Documentation for all the tests conducted and their reports is maintained in records, for references and submission to the relevant authorities and the users of the same.

As precast use of concrete is conducted in a dedicated space and is in a monitored environment, it becomes easier to maintain high quality due to its repeatability factor. The necessary general precast machinery and moulds, steel tables, concrete batching and dispensing equipment, vibrating and finishing equipment and dedicated labour team help maintain the higher quality standards as compared to cast in-situ use of concrete.

How do you incorporate sustainability in the process of precasting?
Precast use of concrete promotes sustainability with its repeatability factor. There’s more planning involved in the process and equipment like the moulds, vibrating machine, finishing machine are all reusable elements of the process.
As mentioned, there is planning in precast use of concrete where only the required measure of concrete is mixed and poured into moulds that are made to precision as per the requirement of the project. The quantity is also previously defined, which means there is reduced to zero wastage of material.
This waste reduction leads to lesser needs of cleaning and clearing equipment, which may further be fueled by other energy sources. Thus, precast concrete, by large, is a sustainable means of building.

What are the advantages of using precast concrete?
There are multiple advantages of using a precast structure for any project like cost efficiency, speed, versatility, safety, sustainability and beauty.
This includes:

  • The use of precast improves the quality and lifespan of any building
  • It reduces the time of building, thus reducing the costs involved for all the other equipment and labour that goes in to the project, thus, proving to be cost effective
  • The maintenance of a precast is lower due to its high quality and durability that is ensured while it is cast
  • This method of using concrete is a sustainable option due to its repeatability

What are the major challenges you face in the process of making precast shapes and in their transportation?
The precast industry plays on volume and repetition. This is one of the major challenges as well.
The requirement of having to repeat the process
that contains a large volume of mixed concrete and getting the same perfection in the shapes is a cumbersome process.
The initial investment in setting up the precast plant and acquiring all equipment and moulds is high. With bulk shapes to be transported from one place to another and the requirement for site space and handling, this time of concrete use is more suitable for tier 2 and tier 3 cities.

How do precast elements or shapes help in the profitability of a construction activity?
As precast concrete is made at a different location than the construction site, the other jobs keep going on at the site and then the precast shapes are placed there. This reduces construction time to up to one-third to one-fifth as compared to cast in-situ concrete, thus, reducing cost of the construction.
Construction maintenance is reduced as the quality of their precast structures are monitored and carefully administered at the plant level. This means it adds to the reliability, durability, accuracy, and ability to produce architectural elements in any building adding to its quality and strength. Precast also provides insulation, thermal inertia and fire resistance and the possibility of integration with MEP (Mechanical, Electrical and Plumbing) from the start of the project.

How can precast concrete contribute towards affordable mass housing in India?
Defined shapes and technical requirements in precast concrete helps reduce the waste and increase the repeatability factor, thus, reduces the cost and time for any construction or building project. Higher control on quality, less time consumer leads to lesser need of labour and equipment on-site, which also adds to the profitability of the structure.
All factors combined bring down the overall cost of the project, leading to that benefit translating to the end consumer and bringing a surge of affordable mass housing in India.

-Kanika Mathur

Comparison Between Cast-in-situ (conventional method) versus Technology Drive Precast

Sr. No Criteria Conventional Construction Precast Construction 3D Modular/ Panel & Hollow Core Slab.
1 Natural resource consumption High 30 per cent saving
2 Labour Problem Heavy labour problem while work in progress Less labour required
3 Dependability on skilled labor 60 per cent Dependability
4 Time consuming Verv High Fast track
5 Initial investment Low High
6 Finishin Normal Excellent
7 Quality production Poor Excellent as factory based.
8 Material wastage High Least
9 Speed/ Productivity Low Excellent
10 Strength Good Excellent
11 Durability Low High
12 Structure weight/ Deed load Very heavy Reduced
13 Brick Block and Plastering Required No Need
14 Service like Electrical, plumbing & sanitary Break, Provide & Re-build Pre-embedded

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Concrete

The age of concrete blocks can be up to a 100 years

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Nikita George, Director Operations, APCO Concrete Blocks and Allied Products, takes us through the manufacturing process of concrete blocks and its composition and also specifically discusses their patented product – cellular blocks.

Tell us about the type of concrete blocks that your organisation manufactures.
We manufacture mainly solid and cellular concrete blocks. The cellular block is our patented product, which has become increasingly popular due to its high utility value in the construction process. We are also gearing up to launch our new line of pavers and kerb stones by the end of August.

What is the composition of each type of block and what are their strengths?
Blocks constitute of mainly three items:
Cement,

  • Manufactured Sand and Stone Aggregates Our patented cellular blocks have a vast set of benefits:
  • Lightweight: The cellular block is between 8 to 9 kg lighter than the solid block. This not only increases the productivity of the labour but also helps in reducing the overall steel requirement for the project.
  • Thermal insulation properties: With the erratic weather conditions in India today, cellular blocks help in maintaining thermal insulation properties within the building. In a recent experiment conducted on a building, which used the cellular blocks, a marked reduction in temperature by three degrees was recorded.
  • Sound insulation properties: Due to the hollow nature of these concrete blocks, the product is able to cut the decibel levels by 14 per cent.
  • Compressive strength and water absorption properties: The cellular blocks exceed the ISO parameters for compressive strength and water absorption.

How do you ensure quality standards for the concrete blocks manufactured?
With our 50 years of experience in the concrete blocks manufacturing industry, we have continually evolved and tried our best to stay relevant with the international quality standards. Quality control begins with procurement of good quality raw material. Fortunately, we have our own crushers to cater to our production units. This helps us negate undesirable raw materials. State of the art machinery and a strong base of SOP help mitigate errors. Above all, of these we have a skilled set of managers who have over 25 years of experience in the concrete blocks field.

Tell us about the sustainability and environmental benefit while manufacturing and while using these blocks in construction?
The blocks that we manufacture follow the highest quality parameters that give a very long life span. When used in building, the age of concrete blocks can be up to 100 years. The blocks used in these buildings at the time of demolition can be re-crushed and used to manufacture the same product again. And since concrete blocks are one of the strongest products available in the market, the on site damages are virtually zero. Unlike native methods of concrete production, we use only M-sand. There is no usage of river sand hence, safeguarding our environment. Also, as mentioned before, concrete blocks can be reused even after the lifespan of a building. This cuts down on further usage of raw materials.

What are the key benefits that any builder can get from using your concrete blocks?
The concrete blocks industry to a large extent can still be categorised in the unorganised sector. Due to this, there is a lot of disparity in pricing and quality in the market. At APCO, with our 50 years of experience, we have won the trust of our customers by consistently proving the highest quality of our products and on-time delivery.
With our 5 production units strategically located around Bangalore city, we have the capability of producing up to one lakh blocks per day. This allows us to consistently supply large quantities to our customers. Our customers can also be assured that the quantity of blocks that leave our plants is the same quantity that will be unloaded at the site.
Apart from this as mentioned in the earlier answers, our cellular blocks host a wide range of benefits during and even after the construction of a building.

How do these concrete blocks contribute to the profitability of construction?
When APCO came into the market in the early ’70s, the construction industry was heavily reliant on the traditional clay bricks. It took us about 10 years before we got our first big break. And since then, the construction market has not looked back. There have been multiple competitors in the walling solutions market but in terms of pricing and quality no other product comes close. Most people build a house once. At APCO, we believe in making that house a home. We provide unrivalled quality and a fair price to all our customers!

What does the near future hold for APCO Concrete Blocks and allied products?
We will be launching our new product line of pavers and kerb stones by August and we are working towards APCO being present in a few more states around India.

Kanika Mathur

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Concrete

Effects of Macronomics

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In any industry, it always helps to take into account the macro perspective as it aids one in navigating the broader economic trends. As per the assessments of the April-June quarter (Q1), India’s gross domestic product (GDP) increased 13.5 per cent, which was lower than RBI’s estimated 16.2 per cent. A fiscal deficit of Rs 3.41 trillion was noted during the April-July period this financial year.


Moody’s Investors Service has revised India’s economic growth projection for 2022 to a reduced 7.7 per cent. The downward revision is due to rising interest rates, an uneven monsoon and global demand slowdown, which is not surprising as the Russia-Ukraine war continues to cast its shadow. The eight core infrastructure sectors, including cement, slowed down to 4.5 per cent in July, which afforded the service sector to shine in the first quarter.


Taking a bird’s eye view of the cement sector, the upward moving trends are looking promising and that has kept optimism buoyed amongst the players. Monsoon is a tricky time for the cement industry as construction takes a backseat and price fluctuations in cement are rife.

As per Kotak Institutional Equities report, cement prices have declined about a percent sequentially in the second quarter. Cement price was recorded at Rs 384 per 50 kg bag in August pan-India. In spite of a sluggish season, the demand is likely to soar in the coming months, and the key players in the industry are anticipating robust growth.


There is a lot that’s underway for cement manufacturers in terms of alternative raw materials, energy efficiency and eco-friendly processes. Given the infrastructure and construction boom that India is witnessing today, the cement segment is likely to perform well. However, the challenges that the sector faces are unique to it, and it remains to be seen how cement brands will innovate to overcome them.

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