Better Waste Management: Alternative Fuels & Raw Materials
Daily 0.2 million tonnes of waste is generated in India. Waste collection efficiency ranges between 20 and 25 per cent out of municipal waste collected. Of this 94 per cent is dumped in land and 5 per cent composited. Waste will increase between at phenomenal rate. between 2005 and 2025. This can be recycled to generate new products, such as cement and not just a waste incineration.Alexander Koshi is a chemical engineer with 39 years experience in cement industry in India, Saudi Arabia, UAE, Oman, Bahrain, Bangaladesh and Kuwait. He is a major international conference speaker.Cement manufacturing is a large scale industrial process with high energy consumption and a potential for co-processing of high quantities of alternate fuel and raw material (AFR). AFR can be recycled to generate new products, such as cement. It is not just a waste incineration. The co-processing of AFR in the clinker manufacturing process is environmentally-friendly.Evaluation Of AFRCharacteristics:
- Thermal substitution of coal with waste up to 40 per cent in 1 million tonne cement plant will reduce the CO2 emission by 100,000 tonne.
- Saves fossil fuel considering India’s kiln capacity of about 300 million tonnes 5 per cent substitution will save 2.5 million tonnes of coal annually.
- It is the most environment-friendly way to dispose hazardous waste as it recovers energy from waste and leaves no residue.
- Saves money. There is no need to invest in incinerators and landfills to dispose the hazardous waste that India generates. India’s present cement kiln capacity is good enough for the next decade or more.
Advantages of the clinker manufacturing using waste fuelsFirst of all, a utilisation of secondary or waste derived fuels, so called WDF?s in the clinker manufacturing process is a real recycling. It is not just an incineration. Moreover, due to the strict alkalinity of the process practically all inorganic compounds, like heavy metal elements are immobilised in the clinkers minerals without negative influence on the quality of the product as those compounds are diluted below as significant values. In addition these elements are not re-mobilised during the hydration process of the cement and hence no pollution, for example of the ground water is possible, as this is a serious problem of landfills.As proven by intensive investigations, the organical compounds of WDF’s are completely ed down to a methane-like base molecule by an extreme high temperature profile of the thermal system of up to 1550 ?C. This methane-like compound is easy to ignite and to combust.Furthermore, due to the high gas velocities and the related short retention time in the thermal system the window of de novo synthesis of dioxins and furans is very short and no significant reformation of those hazardous compounds takes place. In waste incineration plants, tremendous technical provisions are necessary in order to cover this problem.Liquid Waste Firing Through Burner
- Injection of the liquid waste should be done through the centre of the burner and coal as a primary fuel can be injected through the outer annulus. Higher velocity at the burner tip is required in case of multi fuel firing and hence necessity of an axial blower is envisaged in case the primary air quantum is low.
- Two phase injection nozzle for hazardous liquid waste firing is recommended to achieve sufficient fineness of the droplets
- Atomisation of the primary air is envisaged and hence any kind of compressor along with an air vessel is necessary to assure stable injection of the liquid waste. Air pressure of the compressor should be in the range of 6-8 bar for an atomisation viscosity of 25-40 cSt.
- Opening size of the nozzle diameter is of prime importance for firing of liquid waste due to its solid content (possibility of the nozzle to get plugged). Hence, required opening would be determined after having the detailed analysis of the solid content in the hazardous liquid waste.
- Precautions are to be taken to avoid any damage due to back pressure generating from the system during upset condition of the kiln, if any.
The Indian Waste Management ScenarioIndian population is 1.2 billion in roll and increasing. Daily 0.2 million tonnes of waste is generated around in 28 states and 7 union territories with total 38 million tonnes annually. Waste collection efficiency ranges from 20-25 per cent out of municipal waste collected 94 per cent is dumped in land and 5 per cent composited. Waste will increase between 2000 and 2025 at phenomenal rate. In 2009, about 67 million tonne of hazardous waste was generated.The waste collection will undergo the following changes.
- Organic waste will go up from 40 to 60 per cent.
- Plastic will rise from 4 to 6 per cent
- Metal will escalate from 1 to 4 per cent
- Glass will increase from 2 to 3 per cent
- Paper will climb from 5 to 15 per cent
- Others (ash, sand, grit) will decrease from 47 to 12 per cent
Action To Improve AFR
- India emerging as developed country must consider use of AFR in cement industry to improve quality of life of its growing population.
- The conditions in rotary kilns guarantee that the use of AFR is ecologically safe.
- The hazardous waste, more than 1,80,000 tpa is available. This can be used in cement kiln to produce 38 x 105 GJ of heat energy. This will help to reduce CO2 emission and solve land filling problem. Use of AFR in cement plants is both ecologically and economically justified.
- The barriers to AFR use in India are technological and economical barriers. But the critical issue who pays and globally it is found that the polluter pays. There is complete disconnect between the user and giver. The government has to setup laws and regulations followed by integrated solid waste management hierarchy (ISWM) with a strong legal frame work. Economical incentives have to be provided for RDF production and utilisation such as offering tax free and soft loan for machinery lower taxes for companies, those use RDF. The cement manufactures association with National Council of Building materials and central pollution control board (CPCB) with central and local governments must work in synergy to solve the problem.
Indian cement industry is well known for its energy and natural resource efficiency
Dr Hitesh Sukhwal, Deputy General Manager – Environment, Udaipur Cement Works Limited (UCWL) takes us through the multifaceted efforts that the company has undertaken to keep emissions in check with the use of alternative sources of energy and carbon capture technology.
Tell us about the policies of your organisation for the betterment of the environment.
Caring for people is one of the core values of our JK Lakshmi Cement Limited. We strongly believe that we all together can make a difference. In all our units, we have taken measures to reduce carbon footprint, emissions and minimise the use of natural resources. Climate change and sustainable development are major global concerns. As a responsible corporate, we are committed with and doing consistent effort small or big to preserve and enrich the environment in and around our area of operations.
As far as environmental policies are concerned, we are committed to comply with all applicable laws, standards and regulations of regulatory bodies pertaining to the environment. We are consistently making efforts to integrate the environmental concerns into the mainstream of the operations. We are giving thrust upon natural resource conservation like limestone, gypsum, water and energy. We are utilising different kinds of alternative fuels and raw materials. Awareness among the employees and local people on environmental concerns is an integral part of our company. We are adopting best environmental practices aligned with sustainable development goals.
Udaipur Cement Works Limited is a subsidiary of the JK Lakshmi Cement Limited. Since its inception, the company is committed towards boosting sustainability through adopting the latest art of technology designs, resource efficient equipment and various in-house innovations. We are giving thrust upon renewable and clean energy sources for our cement manufacturing. Solar Power and Waste Heat Recovery based power are our key ingredients for total power mix.
What impact does cement production have on the environment? Elaborate the major areas affected.
The major environmental concern areas during cement production are air emissions through point and nonpoint sources due to plant operation and emissions from mining operation, from material transport, carbon emissions through process, transit, noise pollution, vibration during mining, natural resource depletion, loss of biodiversity and change in landscape.
India is the second largest cement producer in the world. The Indian cement industry is well known for its energy and natural resource efficiency worldwide. The Indian cement industry is a frontrunner for implementing significant technology measures to ensure a greener future.
The cement industry is an energy intensive and significant contributor to climate change. Cement production contributes greenhouse gases directly and indirectly into the atmosphere through calcination and use of fossil fuels in an energy form. The industry believes in a circular economy by utilising alternative fuels for making cement. Cement companies are focusing on major areas of energy efficiency by adoption of technology measures, clinker substitution by alternative raw material for cement making, alternative fuels and green and clean energy resources. These all efforts are being done towards environment protection and sustainable future.
Nowadays, almost all cement units have a dry manufacturing process for cement production, only a few exceptions where wet manufacturing processes are in operation. In the dry manufacturing process, water is used only for the purpose of machinery cooling, which is recirculated in a closed loop, thus, no polluted water is generated during the dry manufacturing process.
We should also accept the fact that modern life is impossible without cement. However, through state-of-the-art technology and innovations, it is possible to mitigate all kinds of pollution without harm to the environment and human beings.
Tell us about the impact blended cement creates on the environment and emission rate.
Our country started cement production in 1914. However, it was introduced in the year 1904 at a small scale, earlier. Initially, the manufacturing of cement was only for Ordinary Portland Cement (OPC). In the 1980s, the production of blended cement was introduced by replacing fly ash and blast furnace slag. The production of blended cement increased in the growth period and crossed the 50 per cent in the year 2004.
The manufacturing of blended cement results in substantial savings in the thermal and electrical energy consumption as well as saving of natural resources. The overall consumption of raw materials, fossil fuel such as coal, efficient burning and state-of-the-art technology in cement plants have resulted in the gradual reduction of emission of carbon dioxide (CO2). Later, the production of blended cement was increased in manifolds.
If we think about the growth of blended cement in the past few decades, we can understand how much quantity of , (fly ash and slag) consumed and saved natural resources like limestone and fossil fuel, which were anyhow disposed of and harmed the environment. This is the reason it is called green cement. Reduction in the clinker to cement ratio has the second highest emission reduction potential i.e., 37 per cent. The low carbon roadmap for cement industries can be achieved from blended cement. Portland Pozzolana Cement (PPC), Portland Slag Cement (PSC) and Composite Cement are already approved by the National Agency BIS.
As far as kilogram CO2 per ton of cement emission concerns, Portland Slag Cement (PSC) has a larger potential, other than PPC, Composite Cement etc. for carbon emission reduction. BIS approved 60 per cent slag and 35 per cent clinker in composition of PSC. Thus, clinker per centage is quite less in PSC composition compared to other blended cement. The manufacturing of blended cement directly reduces thermal and process emissions, which contribute high in overall emissions from the cement industry, and this cannot be addressed through adoption of energy efficiency measures.
In the coming times, the cement industry must relook for other blended cement options to achieve a low carbon emissions road map. In near future, availability of fly ash and slag in terms of quality and quantity will be reduced due to various government schemes for low carbon initiatives viz. enhance renewable energy sources, waste to energy plants etc.
Further, it is required to increase awareness among consumers, like individual home builders or large infrastructure projects, to adopt greener alternatives viz. PPC and PSC for more sustainable
What are the decarbonising efforts taken by your organisation?
India is the world’s second largest cement producer. Rapid growth of big infrastructure, low-cost housing (Pradhan Mantri Awas Yojna), smart cities project and urbanisation will create cement demand in future. Being an energy intensive industry, we are also focusing upon alternative and renewable energy sources for long-term sustainable business growth for cement production.
Presently, our focus is to improve efficiency of zero carbon electricity generation technology such as waste heat recovery power through process optimisation and by adopting technological innovations in WHR power systems. We are also increasing our capacity for WHR based power and solar power in the near future. Right now, we are sourcing about 50 per cent of our power requirement from clean and renewable energy sources i.e., zero carbon electricity generation technology. Usage of alternative fuel during co-processing in the cement manufacturing process is a viable and sustainable option. In our unit, we are utilising alternative raw material and fuel for reducing carbon emissions. We are also looking forward to green logistics for our product transport in nearby areas.
By reducing clinker – cement ratio, increasing production of PPC and PSC cement, utilisation of alternative raw materials like synthetic gypsum/chemical gypsum, Jarosite generated from other process industries, we can reduce carbon emissions from cement manufacturing process. Further, we are looking forward to generating onsite fossil free electricity generation facilities by increasing the capacity of WHR based power and ground mounted solar energy plants.
We can say energy is the prime requirement of the cement industry and renewable energy is one of the major sources, which provides an opportunity to make a clean, safe and infinite source of power which is affordable for the cement industry.
What are the current programmes run by your organisation for re-building the environment and reducing pollution?
We are working in different ways for environmental aspects. As I said, we strongly believe that we all together can make a difference. We focus on every environmental aspect directly / indirectly related to our operation and surroundings.
If we talk about air pollution in operation, every section of the operational unit is well equipped with state-of-the-art technology-based air pollution control equipment (BagHouse and ESP) to mitigate the dust pollution beyond the compliance standard. We use high class standard PTFE glass fibre filter bags in our bag houses. UCWL has installed the DeNOx system (SNCR) for abatement of NOx pollution within norms. The company has installed a 6 MW capacity Waste Heat Recovery based power plant that utilises waste heat of kiln i.e., green and clean energy source. Also, installed a 14.6 MW capacity solar power system in the form of a renewable energy source.
All material transfer points are equipped with a dust extraction system. Material is stored under a covered shed to avoid secondary fugitive dust emission sources. Finished product is stored in silos. Water spraying system are mounted with material handling point. Road vacuum sweeping machine deployed for housekeeping of paved area.
In mining, have deployed wet drill machine for drilling bore holes. Controlled blasting is carried out with optimum charge using Air Decking Technique with wooden spacers and non-electric detonator (NONEL) for control of noise, fly rock, vibration, and dust emission. No secondary blasting is being done. The boulders are broken by hydraulic rock breaker. Moreover, instead of road transport, we installed Overland Belt Conveying system for crushed limestone transport from mine lease area to cement plant. Thus omit an insignificant amount of greenhouse gas emissions due to material transport, which is otherwise emitted from combustion of fossil fuel in the transport system. All point emission sources (stacks) are well equipped with online continuous emission monitoring system (OCEMS) for measuring parameters like PM, SO2 and NOx for 24×7. OCEMS data are interfaced with SPCB and CPCB servers.
The company has done considerable work upon water conservation and certified at 2.76 times water positive. We installed a digital water flow metre for each abstraction point and digital ground water level recorder for measuring ground water level 24×7. All digital metres and level recorders are monitored by an in-house designed IoT based dashboard. Through this live dashboard, we can assess the impact of rainwater harvesting (RWH) and ground water monitoring.
All points of domestic sewage are well connected with Sewage Treatment Plant (STP) and treated water is being utilised in industrial cooling purposes, green belt development and in dust suppression. Effluent Treatment Plant (ETP) installed for mine’s workshop. Treated water is reused in washing activity. The unit maintains Zero Liquid Discharge (ZLD).
Our unit has done extensive plantations of native and pollution tolerant species in industrial premises and mine lease areas. Moreover, we are not confined to our industrial boundary for plantation. We organised seedling distribution camps in our surrounding areas. We involve our stakeholders, too, for our plantation drive. UCWL has also extended its services under Corporate Social Responsibility for betterment of the environment in its surrounding. We conduct awareness programs for employees and stakeholders. We have banned Single Use Plastic (SUP) in our premises. In our industrial township, we have implemented a solid waste management system for our all households, guest house and bachelor hostel. A complete process of segregated waste (dry and wet) door to door collection systems is well established.
Tell us about the efforts taken by your organisation to better the environment in and around the manufacturing unit.
UCWL has invested capital in various environmental management and protection projects like installed DeNOx (SNCR) system, strengthening green belt development in and out of industrial premises, installed high class pollution control equipment, ground-mounted solar power plant etc.
The company has taken up various energy conservation projects like, installed VFD to reduce power consumption, improve efficiency of WHR power generation by installing additional economiser tubes and AI-based process optimisation systems. Further, we are going to increase WHR power generation capacity under our upcoming expansion project. UCWL promotes rainwater harvesting for augmentation of the ground water resource. Various scientifically based WHR structures are installed in plant premises and mine lease areas. About 80 per cent of present water requirement is being fulfilled by harvested rainwater sourced from Mine’s Pit. We are also looking forward towards green transport (CNG/LNG based), which will drastically reduce carbon footprint.
We are proud to say that JK Lakshmi Cement Limited has a strong leadership and vision for developing an eco-conscious and sustainable role model of our cement business. The company was a pioneer among cement industries of India, which had installed the DeNOx (SNCR) system in its cement plant.
NTPC selects Carbon Clean and Green Power for carbon capture facility
Carbon Clean and Green Power International Pvt. Ltd has been chosen by NTPC Energy Technology Research Alliance (NETRA) to establish the carbon capture facility at NTPC Vindhyachal. This facility, which will use a modified tertiary amine to absorb CO2 from the power plant’s flue gas, is intended to capture 20 tonnes of CO2) per day. A catalytic hydrogenation method will eventually be used to mix the CO2 with hydrogen to create 10 tonnes of methanol each day. For NTPC, capturing CO2 from coal-fired power plant flue gas and turning it into methanol is a key area that has the potential to open up new business prospects and revenue streams.
Sustainable Mining for the Future
ICR presents a case for responsible reporting across the mining supply chain.
The importance of mining, in times of sustainability reporting, is rising in stature. The rise of mining output is not waning but growing and the share of construction mineral ore in all of this still remains close to 50% of the entire extractive output.
It is estimated that the global combined extractive output in mining is going to grow to 167gt in 2060, from the 2019 statistics of 92 gt. Out of this 27% is biomass, 15% is fossil fuel, 9% is metal ores and the balance is non-metallic minerals, bulk of which goes to the construction industry. While sustainability considerations would be driving most of the future growth, most notably, metals will be needed for electric storage batteries (eg. for electric cars), which require aluminium, cobalt, iron, lead, lithium, manganese and nickel but also for other relevant technologies, including those used for the production of wind turbines and solar panels; far greater amounts of metals are needed for clean energy production than the traditional energy production from fossil fuels. Thus the growth in metals for sustainability will offset the drop in extraction that would stem from growth in recycling.
An overview of the mining sector
Mining for non-metallic minerals, from where the construction industry sources all its inputs, perhaps falls under the ASM (artisanal and small-scale mining), which has still remained labour intensive and suffers from safety issues all across, the developed world and developing, all have the similar challenges to grapple with. Efforts to increase automation, mechanisation and digitisation also come with the fair share of demands from the local community, which can hardly be neglected. While Large Scale Mining (LSM) is moving towards mechanisation and automation with minimum labour resources, the focus is increasingly shifting towards partnerships on supply chains that connect local procurement partners and the community at large to the external markets.
One of the significant developments has been the shift towards battery-electrification of mobile equipment in the mines to the complete automation of all mining equipment with Net zero targets in focus. There are man-less mines in existence already where underground operations are being orchestrated through battery-electric equipment remotely connected through control systems. The partnerships between mining companies and the mining equipment OEMs is ensuring a smooth transition in this area that will take the use of fossil fuels in mines to a negligible proportion (mostly as consumables) in the near future. This however calls for a skills inventory crossover, that would need larger hand holding with the local government and other institutions as well as the local communities.
Sustainability in mining
The goals of sustainable development in mining would include transparency as a key theme between a large pool of actors that constitute and connect the upstream to the downstream supply chain partners (supplier, trader, smelter refiner, component producer, contract manufacturer, end user, intermediaries, agents and transporters). This would also entail collaboration with governments and across the supply chain to support a circular economy to minimise inputs to waste from the mining process and to increase the reuse, recycling and repurposing of raw materials and products to improve sustainable consumption. The traceability systems also ensure that the level of information that is shared and disclosed along the value chain. They illustrate the chain of custody, which is the sequence of stages and custodians the product is transferred to through the supply chain.
The transparency of reporting across the entire supply chain is at the core of this and this has two parts:
- Minimise resource use and waste (use of water, energy, land and chemicals and minimise production of effluent, waste and chemicals) and also purpose waste rock
- Incorporate life cycle thinking (extend responsible sourcing to all suppliers and collaborate to connect the consumer with sustainable raw materials).
India-centric big picture
India as a country has progressed well in SDG Reporting and Sustainable Development in the mining sector that accounts for 2.5% of the country’s GDP. Many of the key companies of the sector are SOEs. India is abundant in natural mineral resources and the country is one of the world’s main producers of iron ore and bauxite. India is the third largest producer of coal, behind the US and China. In construction related extractive minerals, India is the world’s second largest producer. Section 135 of India’s Companies Act on CSR and Regulation for large public companies to produce Business Responsibility Reports, makes it imperative for Large Mining companies (both metallic and non-metallic extractive ones) to be part of the SDG reporting, that cover diverse range of sustainability areas including GHG gas emissions, energy use, stakeholder engagement and labour and human rights.
In 2011, the Indian Ministry of Corporate Affairs issued the National Voluntary Guidelines on the Social, Environmental and Economic Responsibilities of Business (NVGs). Building on the NVGs, a new guidance entitled the National Guidelines on Responsible Business Conduct (NGRBC) was released in 2018. The new guidance integrates the ‘Respect’ pillar of the United Nations Guiding Principles and the UN Sustainable Development Goals.
Following other countries, India is also on the path of developing sustainability guidelines for the end-to-end supply chains in the mining sector. This will only ensure stakeholder participation for safety and sustainability in all four stages: profiling, reservation, exploration and departure. For future growth in mining, that will entail coal, iron-ore, bauxite and limestone extraction as the top four mining categories, it is an absolute necessity that focus on SDG reporting is carried through beyond the voluntary reporting mandate to encompass the aspirations of the communities and investors who would be the major beneficiaries of such initiatives. Without their blessings, the growth in these sectors would be mired by distrust and lack of transparency, which remains to be one of the dampeners for sustainable growth in mining.