Efforts are on but miles to go
While industries of all kinds are exploring ways to reduce their carbon footprints, the cement industry is no exception. Cement is the most widely used man-made material in existence - it forms concrete when mixed with water, and is used in the construction of everything from buildings to bridges to roads and sidewalks and all kinds of other infrastructure.
The biggest problem for cement industry is its manufacturing process, because it releases large amounts of carbon dioxide. The industry's huge carbon footprint stems from its high fuel requirements, which are mostly satisfied by fossil fuels. But more than half of its emissions-and perhaps as much as two-thirds, by some estimates-actually come from the chemical production process itself, which releases large amounts of carbon dioxide as a byproduct.
The carbon capture technology, though much talked about is yet to take off in real terms. There are many challenges, the cement industry is a highly conservative sector, Sant, one of the UK-based scientist noted - and not without reason. The construction of essential infrastructure, like buildings and bridges, carries a great deal of concern about safety and high anxiety toward the introduction of newer, less-proven materials. "Because we've used this material for as long as we have, there's a lot of user confidence associated with it," Sant said. This may have made the industry more resistant than others to innovation.
CDP's (a U.K.-based organisation) where Sant is associated with advocates for transparency about corporations' environmental footprints. In one of the reports it evaluated 13 of the world's largest publicly listed cement companies on their readiness for a low-carbon transition. It suggests that the companies' emissions have been falling by about 1 per cent annually, on average. But it notes that this is hardly enough to keep pace with trajectories consistent with a 2 degree Celsius climate goal. The report also points out that investment in research and development, as a proportion of sales, is low compared with other industries. This has been the global scene in the cement manufacturing sector.
As pointed out in the discussion by Vivek Patni, Director, Wonder Cement on climate change, these groups (Climate change activists) will ask for reduction of CO2 and NOx (both are greenhouses gases). With the new development in technologies and research in progress, CO2 capturing will be possible. With changes in cement manufacturing process, NOx reduction is also very much possible. As he says but it will take some time, he further stresses that "However, the new technology of CO2 capturing and NOx reduction becoming technically and commercially viable may take some time but it will be possible to minimise the impact on climate change by technology adoption. The real challenges on capacity addition/size of plant are from the land owners in the context of cement industry, with the new regulations of land acquisition."
The overall changes of new regulations have been accepted by the industry. The industry has become more clean and green in the last two decade. It is continuously working on reduction of greenhouse gases. It may take a little longer than the schedule considering the COVID-19 pandemic. The enforcement of new regulation will force industry to adopt to new technologies, increase production of blended cements, more installations of WHRS, move towards alternate fuels and use of marginal quality of lime stone. The industry will have to invest money on all these new initiatives but in the long run it will bring down the operating cost and improve efficiency.
The new regulations of SPM of 30 mg/nm3 is very well adopted by industry. This limit depends upon the age and location of the plant. The Indian cement industry is working on controlling NOx as prescribed by regulating authorities. Achieving the latest requirement on NOx has been a challenge for industry. It is in the process of installing SCNR and also re-designing the process to minimise NOx generations. ESP is being replaced with bag filters. The limit of Sulphur dioxide emitted from a cement plant was increased from 100 mg/Nm3 to 100 to 1,000mg/nm3. This limit depends on Sulphur content in limestone, a raw material for making cement.
The limit for nitrogen oxide was relaxed from 600 to 800 mg/nm3 to 600-1,000 mg/nm3. This should come as a surprise because China, which is the largest producer of cement, has set the limit for the former to 200 mg/nm3 and for the latter to 400-800 mg/Nm3. Countries like South Africa, Australia, Germany and many other European countries have stipulated the emission limits for Sulphur dioxide as low as 50 mg/nm3. Similarly, countries like Colombia, Germany and other European countries have Nitrogen oxides emission limit as low as are 200 mg/nm3. Besides, many countries have stipulated limits for mercury, which India is yet to do.
According to the observations made by the Centre for Science & Environment, the revised norms are lenient as compared to the August 2014 norms for normal cement plants and the July 2015 draft norms for co-processing cement plants. While normal cement plants just make cement, co-processing cement plants also burn wastes, generating toxic pollutants such as hydrogen fluoride, hydrogen chloride, total organic carbon, dioxins and furans and heavy metals and their compounds, which require monitoring. Although the ministry specified separate norms for these plants, the limits for particulate matter, Sulphur dioxide and nitrogen oxide are the same as the normal cement plants.
However it is appreciable that world's second largest producer by quantum is finally making moves to combat climate change.
The other topic though not directly of emission but we would like to touch up on which is indirectly connected with it. In this issue itself we are carrying coverage on construction and demolition waste. We are of the opinion that this has been a neglected subject by the regulators and seek immediate attention. It could have been well incorporated in the smart city initiative. We are all aware how the shortage of natural sand is badly hitting the construction sector. A well thought out tackling of construction and demolition waste can offer some relief. We would urge all the readers to download the detailed report here: https://www.cseindia.org/another-brick-off-the-wall-10325.
- VIKAS DAMLE