Humboldt Wedag India has been at the forefront of technological developments taking place in the cement industry of Indian subcontinent. ASHOK DEMBLA and BALESH SINGH open up a window for us on various aspects of developments.
The Indian cement industry continues to be second largest producer of this commodity in the world. This sector is expected to continue its fast-paced growth and attain installed capacity of 850 million tonnes (MT) per annum by 2030 and 1,350 MT by 2050. The industry has made tremendous strides in technology assimilation and upgradation.
Single production lines of over 12,000 TPD (tonnes per day) with multi-stream pre-heaters and calciner, thermal energy consumption of 685 Kcal/Kg clinker, or electrical energy consumption of 70 kWh/ton of cement were unimaginable two decades ago when these figures hovered at around 850 Kcal/Kg clinker and 110 KwH ton of Cement respectively.
Some of the important plants supplied by Humboldt Wedag India which are achieving results comparable to best figures in the Industry and sometimes best in the Industry are;
- Rajashree Cement (UTCL) – All four kiln lines, including raw material and cement grinding. The line no 4 is at present operating at 12,000 tpd.
- UTCL Raipur – Kiln No II – Presently operating at 12000 tpd
- UTCL Tadpatri, Kotputli and Aditya Cement (Line II) – Identical Kiln lines, each operating at an average output of 9500-9600 tpd.
- Shree Cement – All kiln lines at Ras, Raipur and one kiln line at Beawar and cement grinding units at Beawar Ras, Khushkhera and Bihar.
- JSW Cement -All cement and Slag Grinding Units at Vijaynagar Nandyal and kiln line at Nandyal.
- KCP Cement – Achieving Electrical Energy Consumption of 45 kWh/t up to Clinkerization and Thermal Energy Consumption of 685 Kcal/Kg Clinker.
Dalmia Cement, Belgaum – Achieving Electrical Energy Consumption of Less than 10 kWh/t for Raw Material Grinding in Roller Press finish grinding KHD has been pioneer in many technologies, to name a few;
I) First 4-stage Preheater Technology – The first plants with 300 tpd capacity and 600 tpd capacity, came in from Humboldt in Andhra Pradesh at the end of the 1960?s.
II)Roller Press Technology – First plants again came from Humboldt in Diamond Cement, Rajashree Cement and Vikram Cement, in the year 1986-87 which have now been upgraded.
III) V Separator Technology – This technology came as a boon for energy-savings and reliability for semi-finish grinding technology in the year 1995.
IV) Alternative Fuels – Extended PYROCLON? and KHD?s Combustion Chamber came as excellent technology to use pet coke, city waste and other waste derived fuels.
V) 5 & 6 Stage Preheater Technology – The first of these type of plants came on line in India e.g. Diamond Cement, Vikram Cement and Rajashree Cement in order to reduce thermal energy consumption.
VI) Latest Generation Grate Coolers – The KHD Grate Cooler got its start at Vikram Cement. Later came the PYROSTEP? Cooler and now PYROFLOOR? cooler. In addition there has been many innovations in Burner Technology, where the original KHD design has become the world standard.
Ref. Pic-2
Energy, Efficiency and Environment
KHD-Humboldt Wedag buzz word for Technology is Energy, Efficiency and Environment.
Energy: The COMFLEX? grinding system consumes less energy compared to other process circuits.. More and more customers began to use this roller press-based system in the finish-grinding mode for Slag, Limestone, and clinker.
Potential in saving with selection of KHD Roller Press circuit than the VRMs:
- 2-3 Kwh/T in Raw Grinding Application as the total department power ranges between 10-12 Kwh/t according to Material hardness.
- 2.0-3.0 Kwh/T in Clinker Grinding.
- 4.0- 5.0 Kwh/T in Slag Grinding in finish mode.
Potential in saving with Selection of KHD Pyro process Technology.
- Lower Specific Heat consumption due to highest collection efficiency of top cyclones, Lower string temperatures due to efficient calciner which contributes about 5-10 Kcal / kgcl savings.
- Majority of KHD Pyro-process circuits are operating in range of 685-695 Kcal/kgcl.
- Specific Power consumption from Mines Crusher to Clinker Silo Feed ranges 48-50 Kwh/t.
-
Efficiency:
- It is proven that KHD COMFLEX? circuits consist of Roller Press gives more efficiency than other Grinding Systems. Under normal operation conditions our STUDDED roller surfaces are maintenance free for more than years Ref.Pic-1,4
- KHD Pre-heaters are proven as efficient pre-heater towards reaction time for de-carbonization and sufficient time for combustion of harder to burn materials like AFR and pet-coke as fuel.
- KHD- Low NOx calciner are known to get more reduction of NOx due to kiln exit gases?s longer retention time in reduction zone.Environment:
- COMFLEX? grinding plants offer a dust-free circuit with no belt conveyers and a very effective de-dusting concept.
- KHD offers the new concept of PYROREDOX? NOx reactor which works under reducing and higher reactivity of NOx reduction in a Loop before entering to calciner which can reduce the NOx below 600 mg/NM3 Ref. Table-1
- Hence no requirement of SNCR or SCR for NOx reduction. Ref. Pic-3
- KHD Pyro jet Burner emerged as most efficient Burner to control Thermal NOx across the Kiln. 200-400 mg/NM3 Ref. Pic-2
Status of Emissions and CEMS – present Status and Challenges
Emissions are released from cement kilns, coming from the physical and chemical reactions of the raw materials and from the combustion of fuels. At present norms exist for dust, TOC, HCl, HF, SOx, NOx Hg, Heavy Metals and Dioxin in India, which are comparable or better as compared to China, Indonesia and Philippines. Ref. Table-2, shows the comparison; Emission Standards at different countries. In India the CEMS system started approximately 5-7 years ago for monitoring particulate emissions and subsequently NOx. Policy guidelines were also formulated and released on 10th May 2016 for emission control by the Ministry of Environment. A brief status as compared to China, Indonesia and Philippines is given in table in next page; As mentioned above the Indian Government (Ministry of environment, forest and climate change) released a new notification on 10th May 2016 for control of emissions released from cement industry.
The Ministry of Environment addressed Emission Limits for old plants as mentioned in table above. Ref. Table1,3Status of Alternate Fuels and Thermal Substitution Rate
KHD Humboldt Wedag has expertise in using alternative fuels either in the calciner or in the kiln. KHD supply award wining Combustion chamber for dry municipal waste and other difficult fuels In fact Humboldt Wedag India supplied Vikram Cement a handling and firing system in order to use of Jaipur City Waste. We also delivered a similar system to Jaypee Cement to use Chandigarh City Waste.Way Forward
With the unlimited growth potential in India, Technological innovations leading to low thermal and electrical energy consumption become the center point of focus. In parallel there is need of environmental friendly technologies for sustainability. Of course everything comes with a price but advancement and success lies in the technological innovations which are effective and cost competitive also. Continual development based on the need from the industry are the foray in which we as cement technology suppliers have to think ahead.
Table-1:
Table-2:
Table-3:
About the authors:
Ashok Dembla, Managing Director, Humboldt Wedag India.
Balesh Singh, Process Head, Humboldt Wedag India.