Director (Energy and Environment), ACC
Being the oldest manufacturer of cement, ACC had faced many technical and financial challenges while upgrading the old processes and equipment. Today ACC operates one of the largest kilns in the world and uses state-of-the-art technologies at its new plants. KN Rao Director (Energy and Environment), ACC Limited, elaborates on innovative measures taken for improvement of energy efficiency of the plants.
How do you rate your company when it comes to sustainable production of cement?
We closed the year 2013 with a sense of satisfaction when we received external recognition with the prestigious ´CII-ITC Sustainability Prize´ in category ´A´ for large companies. The award is acknowledged as being among the top honours for sustainability in organisations across all sectors. We were also ranked as ´The Most Admired Company in Cement Sector in 2013´ by Fortune India magazine.
In 2013, we realised 94,459 Certified Emission Reductions (CERs) from our Clean Development Mechanism (CDM) projects registered with United Nations Framework Convention on Climate Change (UNFCCC) and have submitted verification reports recommending for issuance of 846,313 CERs.
What operational measures have you taken to improve sustainability of your plant?
During the year, we commissioned ACC´s first waste heat recovery power generation unit of 7.5MW, which has the potential to reduce ~44,180 tonnes of CO2 per year while providing 7.5 per cent green energy for the plants.
This shows us a way to set up similar systems at our other plants.
Have you done any modifications in the plant lately to reduce emissions?
On the environment excellence journey, the company´s overall carbon intensity has been cut by 32 per cent since 1990, thanks to proactive and consistent attention. Despite an increase in demand for more ´carbon-intensive´ products like ordinary Portland cement (OPC), ACC was able to reduce overall specific CO2 emissions to 528 kg CO2 /tonne of cement through various initiatives in the entire business operations. Another area of improvement is the reduction of specific kiln dust emissions by as much as 18 per cent. Demonstrating greater transparency, ACC has started online reporting of kiln stack dust emission from various plants to the pollution control boards.
Please tell us in brief about the upgrades done and initiatives taken to improve energy efficiency of your plants.
ACC´s in-house R&D has been driving several innovative approaches to improve plant efficiency. Some of the initiatives are listed below:
Conversion of wet/semi dry kilns to long dry process/suspension pre heater kilns
Disengaging some of the inefficient wet kilns and converting them into the refractory kilns
Increasing the number of stages of suspension pre heater kilns to 5/6/7
Introduction of pre-calciners for increasing the thermal and electrical efficiency
Introduction of high efficiency coolers
Introduction of pre-grinders for improving the grinding efficiency
First to develop energy efficient indigenous (1 MTPA) cement plant
Developed energy efficient mini cement plant with rotary kiln
First to introduce blended cements (PPC and PSC) in India and registered the largest CDM project in the Indian cement industry
Using latest grinding technology of vertical roller mills and roller press with efficient separators for grinding raw materials and finished products
Efficiency improvement of all process equipment like fans, compressors, pumps, material handling systems, size reduction equipments, etc
First to introduce alternative raw material in cement industry
Co-processing of waste and biomass in cement kilns to reduce the CO2 emission
Introduction of high efficiency burners, seals, expert control system and variable speed drives, etc
Conversion of low efficiency (stoker fired boilers) to high efficiency (FBC) boilers
Introduction of CFBC technology for CPP
Extensive use of biomass in CPP
Use of wind energy for cement manufacturing (9 MW), and
Efficient lighting and solar energy usage for water heating and operating small water pumps.
What are the challenges faced while adhering to pollution control norms, especially stack emissions and dust hazard. How have you tackled them?
By its very nature cement manufacturing process is based on size reduction where huge rocks of mined material are crushed to fine powder and then converted to cement. Thus the manufacturing process calls for handling of large amounts of dust mostly in dry form at various stages of manufacturing. ACC with its long experience spanning more than 7 decades, had implemented various measures on continuous basis and will continue to address the issue by deploying the latest available technologies and taking all possible measures.
With all these efforts ACC´s stack emissions have reduced considerably to the current levels of <50mg/Nm3. All our latest air pollution control systems are operating at <20mg/Nm3. ACC has also installed various continuous emission monitoring systems like opacity monitors, CAAQMS, CEMs, etc., for continuous tracking of these emissions and to trigger immediate corrective actions where required. These initiatives have led to reduction of specific kiln dust emissions by as much as 18 per cent. Demonstrating greater transparency, we have started online reporting of kiln stack dust emission from various plants to the pollution control boards.
Please tell us about your efforts in water conservation/water harvesting, etc.
Water stewardship is embodied as a critical part in our sustainable development approach. We strive to maintain zero process waste water discharge, and always look out for better ways to manage our water resources efficiently by way of recycling and rainwater harvesting in mine pits. While some of our plants have become near self-reliant with respect to their water requirements for industrial and domestic consumption by utilisation of harvested rain water, we have devised plans to address water-related risks and are taking measured steps to reduce current dependency on other sources of water. Some of our water conservation and management initiatives include water treatment, recycling and reuse of water. We have systems in place for treating water rejects from plant operations. The treated water is recycled back to the system helping to reduce fresh water requirement. Sewage treatment plants treat sewage generated in the residential townships. The treated sewage water is used for green belt development, while worked out mined pits are used to harvest rain water, which is subsequently consumed by the plant and nearby communities.
The ACC Jamul Cement Works Water Project is one of the examples of ACC´s ongoing projects to utilise water resources in a sustainable manner. ACC Jamul Cement Works in Chhattisgarh has always been conscious of water conservation and harvesting. Since decades, the plant has been harvesting large quantities of rain water in two mined out pits. Here on an average 12-15 lakh m3 of rainwater is collected in each pit every year. Numerous water saving projects were taken up in different areas of the 0plant and colony at Jamul, which resulted in substantial amount of water saving. The achievement of the last year, however, is not an end or a destination but it´s a journey, striving for new objectives and targets.
ACC was able to reduce overall specific CO2 emissions to 528 kg CO2 / tonne of cement through various initiatives in the entire business operations.