Co-processing of waste in cement kilns can become an arm of Swachh Bharat
Co-processing of waste in cement kilns can become an arm of Swachh Bharat

Co-processing of waste in cement kilns can become an arm of Swachh Bharat

To incorporate co-processing of waste in cement kilns in the 'Swachh Bharat' initiative,
KN Rao, Director, (Energy & Environment), ACC Ltd
wants support from the society and munici­palities. He thinks that once regular supply of waste material is ensured, cement industry will definitely invest further to utilise this.
What are your observations on fuel mix optimisation currently being practiced by the industry and by your own plants? Considering there is any restriction put on use of pet coke, where are we headed?
With the introduction of PAT targets for cement sector, most of the cement plants are trying to increase alternative fuels like biomass, industrial waste (hazardous and non-hazardous) in cement kilns. Subsequently, the government for the first time introduced emission norms for SOX and NOX for cement kilns, which need to be complied by August 2018.
In mid 2017, based on the NGT directive, restrictions were imposed on usage of pet coke in various industries. However, the cement kilns were permitted to use pet coke by MoEF and various State Pollution Control Boards. Some states permitted the use of pet coke in the fluidised bed boilers. With many changes mentioned above happened during the last one year, the pet coke usage has come down substantially in CPPs and cement kilns. The biomass availability for cement kilns also reduced as majority of biomass is currently being used by biomass-based captive power plants.
Cement plants desire to use low ash fuels like pet coke instead of high ash coal to produce high quality clinker with slightly lower grade of limestone, which is prevalent in India. The high grade clinker helps in absorbing more fly ash and slag in cement. This will help us to reduce the carbon footprint of the cement production and also mineral gypsum required for cement production.
In the long term, we expect increased use of pet coke and other alternative fuels like RDF, industrial waste (hazardous and non-hazardous) and biomass. Even in the last five years, Indian cement industry had progressed from 0.6 per cent to 4 per cent TSR (thermal substitution rate). The industry had a roadmap to increase TSR to 25 per cent by 2050. TSR do not include pet coke, which is considered as a fossil fuel like coal.
Since there is a restriction of pet coke usage in other industries, we expect pet coke prices to come down in the longer term.
What kind of savings one can expect after second level of PAT audit?
In PAT 2 cycle, we expect that many designated consumers (DCs) will find it difficult to meet the reduction targets given to them. Most of the low cost and quick payback project got implemented in the PAT-1 cycle and the industry DCs have to implement high capex and long payback projects. Due to lack of growth in various sectors and low profitability and compliance, capex required for meeting the new emission norms for various industries for installation of Pollution control system, these high capex projects are not implemented by DCs.
Most of the DCs are going to use the surplus Escerts of PAT-1 cycle to meet the PAT-2 cycle reduction obligations. Even the discount price of Escerts is not attractive to justify high capex projects.
What incremental changes could be done for benchmarking power consumption, fuel consumption? How are you placed on both these parameters?
The cement manufacturing technology has not changed for last couple of decades. Whatever has happened is small incremental changes, which is planning to give a reduction of 5-10 per cent in the electrical energy and 3-5 per cent in thermal energy. Since most of the Indian installed capacity built with modern technology, the opportunities for improvement are minimal.
Currently, as per WBCSD-CSI roadmap data, Indian cement industry stands number one in energy efficiency. The only major levers available are reducing the clinker factor, increasing the alternative fuels and raw materials, installation of waste heat recovery and use of renewable energy for operating the cement plant. For old plants, which commissioned before 1980, there are many opportunities like increase in the number of stages of pre-heater, cooler upgradation, waste heat recovery, grinding technology upgradation, process automation upgradation, installation of variable speed drive and energy efficient fans, compressors, motors, lighting, air conditioning system, etc. However, at the current Escerts prices, large capex projects will be difficult to justify as payback periods will be long. The only area where India can progress on energy efficiency is only through new products like composite cement where we can reduce the clinker factor.
Is WHRS a fashion statement in cement plants? Please comment.
WHRS offers an environment-friendly option of generating power at the cement plant, thereby reducing the dependency on fossil fuel. Though WHRS provides a greener solution, this has several hurdles. Technology such as steam Rankine cycle becomes economical only with sufficient waste gas is available at reasonably higher temperatures. Other technologies such as Organic Rankine Cycle found to be expensive and Kalina cycle technology has two working installations. Both these technologies have a higher capex cost per MW compared to Rankine cycle.
The capex cost for WHRS has not come down in the last few years whereas renewable energy projects (wind and solar) cost have substantially come down with many incentives applicable for renewable energy making WHRS projects less attractive. WHRS projects will not be viable if the plant is running at lower capacity utilisation. Most of the Indian cement kilns are operating between 50 to 80 per cent capacity utilisation due to lack of cement demand growth which is making WHRS less attractive.
If WHRS has been given the deemed renewable energy status, the cement plant can install WHRS to fulfill the RPO obligation. If the cement plant already has a CPP and if the power generated by WHRS is surplus, the State of Electricity Board should agree to import the surplus power at the same price what State Grid charges. If this gets implemented, WHRS in every cement plant will be a reality.
How do you rate the progress in AFR and use of bio fuels? Do you think investments in AFR are adequate to reach the targeted numbers?
Cement industry has advocated for long for utilisation of AFR and biomass in cement kilns through co processing. It is heartening to note that, the Government has understood the positives of AFR and the regulatory processes have become supportive to certain extent. There have been good progress so far in waste utilisation and ACC has installed pre-processing facilities in Wadi, Kymore and Madukkarai and carrying out co-processing in most of the plants. Out of our three pre-processing platforms, our Wadi pre-processing platform is receiving good amount of industrial and municipal waste and we are in the process of expanding its capacity. Currently, ACC is operating with TSR of 3.8 per cent, which we are planning steep growth.
Co-processing of waste in cement kilns can become an extended arm of Swatch Bharat initiative if support is extended from society and municipalities. Once regular supply of waste material is ensured, cement industry will definitely invest further to utilise this. Some of the cement plants in Europe run fully on waste derived fuels. So there exists huge potential.
In 2016 only, the Government of India has recognised co-processing as one of the waste management solution under Hazardous and Other Wastes Management Rules for the purpose of energy or resource recovery or both. After this regulatory change, more and more cement kilns have started using AFR and also investment will be keep coming in phased manner. If the municipalities enforce segregation and processing of waste to make cement grade "RDF", then there will be
large availability of AF for consumption in cement kilns.
What should be the ideal payback period for energy efficiency improvement programmes undertaken by a typical plant?
Ideal payback period for energy efficiency improvement programs are typically less than two years. Above two years it becomes difficult to justify its business case under current market dynamics.
Capacity utilisation of the cement Industry is very low at present; moreover they need to invest huge capex to meet new pollution control norms for Kilns as well as for captive power plants.
After PAT 1 cycle, the potential projects for intensity reduction need considerable capex and most of the plants may not be in a position to invest in this front. Implementing energy saving projects through ESCO companies has not progressed in private sector. ESCO companies in China are implementing approximately of $2 billion of energy saving projects annually whereas in India it is almost insignificant.
What has been the progress on use of alternate energy in cement plants?
Till now, approximately 250 MW of WHRS has got implemented in Indian cement sector. Similarly, more than 200 MW wind and solar projects are implemented till now. Many cement plants are buying renewable bilaterally from third party to meet the RPO obligation for wind and solar. Some of the cement plants are buying solar and non solar RECs from the energy exchange to meet their RPO obligation.
Cement plants have surplus mine and plant land and also have large amount of covered roof space to produce solar PV power of 4-5 MW in each plant.
Approximately 500-750 MW solar PV power generation potential is available in the Indian Cement Industries within the plant boundary. If PAT regulations are modified and benefits are given captive generation status for the installations of RE installed outside the plant boundary and importing into the plant for self consumption.
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