Pankaj Kejriwal, Managing Director, Star Cement, delves into the importance of optimising refractories to make cement manufacturing more cost efficient and eco-friendly.
Tell us about the role of energy in the manufacturing of cement? What is the volume of energy consumption?
A cement plant is a high energy intensive unit. For manufacturing of cement, both thermal energy and electrical energy is required. In the year 2022-23, thermal energy consumption was 27.50 lakh mKcal (82 per cent of total energy) and electrical energy consumption was 5.97 lakh mKcal (18 per cent of total energy). In the cement industry, about 60 kWh of electrical energy is consumed to produce one ton of cement.
The power consumption pattern is as follows:
What are the various modes of energy sources used by your organisation for its manufacturing needs?
The electrical power is taken from various sources such as IEX through open access from state electricity grid and our own captive coal/biomass fuel based thermal power plant, bamboo chips and AFR like RDF is also being used in our plants. We have recently commissioned a 12.3 MW waste heat recovery system (WHRS) plant, and another 12.5 MW WHRS plant is in the pipeline. We are also installing about 15 MW of solar power plant.
The thermal energy is produced by coal in kiln. Linkage coal is utilised in kiln along with various local or purchased coal.
Which of the said energy sources yields maximum productivity for the plant and which yields the least?
Coal, pet coke and electricity are the dominant energy sources used in cement plants, although plants will burn a variety of other fuels, including tires, biomass, RDF and other waste fuels.
As per the mentioned energy sources, WHRS with CPP is our first priority whereas grid (IEX) power is the least priority energy source. As an AFR, we are using bamboo chips, bamboo briquettes and waste plastic bags in our plant. The green energy sources have large impact on the productivity and cost of cement manufacturing. It reduces the carbon emission. As a cost impact, it reduces power cost by 12 per cent in CPP and 1.5 per cent in process plant approximately.
What are the alternative energy sources that are being adapted by the cement industry and your organisation?
The main alternative fuels used in cement industry are residue oil and solvents, contaminated garbage, process waste from food industry / pharma industry, used tires and rubber waste, plastic waste, sewage sludge and waste animal meal. Star Cement uses alternative energy sources such as biomass like municipal waste, bamboo chips and are also installing a 15 MW solar energy plant.
What is the impact of greener energy sources on the productivity and cost of cement manufacturing?
Alternative fuels utilisation in cement industry reduces the production cost and also reduces the coal requirement, coal handling/grinding etc.
How does automation and technology help in optimising the use of energy in cement plants?
By leveraging the power of automation and AI-driven analytics, the cement industry can reduce maintenance costs, enhance equipment reliability, and achieve higher energy efficiency, ultimately leading to improved productivity and profitability.
We are also focusing on automation and technology up gradation to optimise the use of energy in cement plants. To achieve this, various steps has been taken towards energy conservation and technology absorption, few are as mentioned below:
• Installed VFD in Primary Air blower by which control the rpm of blower as per process requirement and saved the energy 86,000 kWh per year.
• Optimisation of RABH purging operation. Total power saving is 2,80,000 kwh per year.
• VFD installed in VRM bag filter of 55 Kw motor, by which saving achieved 7920 kWh per year.
• Increased clinker production and optimised
the running of the different circuits, by which specific power consumption is reduced by 1.08 kwh/MT clinker.
• Optimised the coal firing system and higher clinker production reduced the specific heat consumption by 7 Kcal/kg clinker.
• Installed tertiary crusher in raw mill circuit, thereby increasing ball mill output and reducing power consumption b 2 KW / tonne of raw meal.
What are the major challenges your organisation faces in managing the energy needs of cement manufacturers?
The major challenges for our organisation in managing the energy needs for the cement manufacturing process is the less availability of alternative fuels in plant locality. The segregation of waste is yet to improve and also the Polluter Pay Principle is not being implemented effectively,
thereby increasing the cost of alternative fuel at our factory gate.
Cement industry have a long way to go as far as alternate fuel and raw material usage is concerned.
In spite of several policy, regulatory or technological barriers that industry is facing, now is the opportune time for the Indian cement industry to focus all its efforts in furthering AFR utilisation in its processes.
Tell us about the compliance and standards followed by you to maintain energy use and efficiency in the organisation?
Our organisation is a designated consumer under PAT cycle 2 and 3. We are following all the compliance and standards as per BEE guidelines to achieve our Specific Energy Consumption targets as directed by Bureau of Energy Efficiency, Ministry of Power, Government of India.
As per BEE guidelines Mandatory Energy Audit, monitoring and verification audits are conducted to ensure optimum use of energy after every three years. We have also conducted detailed energy audit by CII, Hyderabad, in May 2023 as an additional exercise.
What kind of innovations in the area of energy consumption do you wish to see in the cement industry?
Use of solar power, hydrogen fuel and maximising the use of AFR are the areas of innovations, we wish to see in the cement industry in near future. Also increasing the efficiency of WHR boilers will help in better recovering the waste heat.
Along with cheaper and greener fuel sources, we would like technology to further reduce the
energy consumption in the grinding process.
Usage of alternative materials, which reduce the overall clinker component in blended cement like LC3 will also go a long way in reducing the
energy requirements.
-Kanika Mathur
