While the Industrial Revolution brought about significant advancements in industry, technology and economic growth, it also had a number of negative impacts on society and the environment. These adverse environmental effects on human health initiated many studies and efforts to minimize industrial pollution through technological advancements in different sectors. Below we are focusing on efforts regarding decarbonizing cement industry and its environmental benefits.
Use of Fossil Fuels and Impacts of Industrial Revolution
The Industrial developments in Europe in the 18th and 19th century was an era of technological advancements, global economic growth and increased urbanization and thus referred to as an industrial revolution which changed the world. But on the other side, its negative impacts, most specifically in terms of environmental safety and climate change have brought about many problems which humanity is facing right now.
The use of fossil fuels and greenhouse gas emissions became the dominant drivers of global warming. As we face the consequences of climate change today, the legacy of the Industrial Revolution serves as a stark reminder of the environmental costs of rapid industrialization and the ongoing need for sustainable practices and energy systems.
What does it mean by “Decarbonizing the Industrial Sector”
In last 10 years, due to increasing concerns over environmental safety, reliance of heavy industries like cement, steel and chemicals on fossil fuels is decreasing and these industries and their systems are being integrated towards renewable energy to reduce industrial carbon emissions.
Most particularly, efforts regarding decarbonizing cement production have made positive changes in the last decade. This sector accounts for around 8-10% of global CO₂ emissions, primarily due to the chemical process of producing clinker and due to burning of fossil fuels for producing heat for its operations.
This is positive change that cement industry is transforming globally to consume renewable energy and waste heat recovery systems for their production, resulting in decline on reliance of fossil fuels. This will reduce greenhouse gas emissions and overall carbon impact on environment.
How Cement Production Affects Environment
Cement is a key ingredient in concrete and Concrete is the second-most-used substance in the world after water and is the most widely used building material. Its consumption worldwide, is twice that of steel, wood, plastics, and aluminum combined. Secondly, it is incredibly dirty to produce while it only constitutes 10-15% of concrete’s mass in a typical mix and up to 90% of its greenhouse gas (GHG) emissions.
The primary source of CO₂ emissions in cement production is the chemical reaction called calcination where limestone (calcium carbonate, CaCO₃) is heated to high temperatures (around 1,450°C) in a kiln (a machine where limestone is burnt), breaking down into calcium oxide, CaO and releasing CO₂. This is a chemical reaction where clinker is found as a product and CO₂ emitted as a byproduct. This process alone accounts for approximately 65% of CO₂ emissions during cement production.
Image: Cement Kiln
Additionally, most plants use fossil fuels such as coal, natural gas, or oil to heat the kilns and burning of these fuels releases large quantities of CO₂, as well as other pollutants like sulfur dioxide (SO₂) and nitrogen oxides (NOₓ).
So, particularly in cement production, the carbon dioxide emissions come from these two primary sources. Due to increased concerns over such an adverse effect, scientists and researchers started thinking on decarbonizing cement production.
For study of complete process of cement manufacturing (ordinary Portland cement OPC), please read our blog.
United States Programs for Decarbonizing Cement Production
In recent steps towards decarbonizing U.S. heavy industrial sector, the United States Department of Energy is initiating decarbonization technologies by investing $6.3 billion in 33 projects across eight industries. This is by far the largest government investment to substantially reduce greenhouse gas (GHG) emissions from industry, the third highest emitting sector in the US.
Currently, the U.S. has 91 operating cement plants that are responsible for 68 million metric tons (Mt) of direct CO2 emissions. The impact can be controlled by incorporating following most advanced techniques for decarbonizing cement production adopted in last 10 years.
Using Blended Cement: To cut U.S. cement and concrete emissions, the most suitable and economical way is to make cements with less clinker. This can be done by introducing supplementary cementitious materials like fly ash, silica fumes, slag and natural Pozzolanic substances to make blended cements.
Using Novel Cements: Another option is to develop new methods and products that avoid emissions from clinker production entirely by using different raw materials containing lesser or no carbon. Recently, Sublime Systems from Somerville, Massachusetts is using an electrochemical process in electricity-powered electrolyzers to turn carbon-free rocks into an alternative cement having strength equal to OPC.
Carbon Capture storage and utilization: Carbon capture storage methods are being used in different industries, most particularly in cement industry, which are used to stop CO2 emitted during conventional production from entering the atmosphere. The CO2 captured is stored underground or utilized in other industries (such as for producing synthetic fuels or chemical industries).
Carbon Minerlization: This is a technology where captured CO2 is injected into the concrete during mixing. The CO₂ reacts with calcium ions in the mix to form calcium carbonate (CaCO₃), a mineral. This process not only improves the strength of the concrete but also sequestering the CO₂, prevents it from entering the atmosphere.
Replacing fossil fuels: Replacing Fossil fuels in production process with biomass or biofuels can significantly reduce carbon emissions.
Waste Heat Recovery system: Cement manufacturing is highly energy-intensive, and a significant amount of heat is lost through exhaust gases, cooling systems, and other processes. Waste heat recovery systems allows cement plants to capture heat generated from hot exhaust gases and use that energy to drive a thermoelectric generator to generate electricity.
Image: Standard Waste Heat Recovery System of a Cement Plant
Shifting to renewable energy sources: Cement production is energy-intensive and shifting to renewable energy sources like solar, wind, and hydropower can reduce the reliance on fossil fuels. Many plants in United States as we all as in many other countries are shifting to these renewable sources to minimize carbon emissions.
Electrification of kilns: The advanced integration of rotary kilns heated mostly by coal and gas, to electric or hybrid kilns (partially powered by electricity) reduces carbon dioxide emissions.
Image: Cement Electric Kiln
Environmental Benefits of Decarbonizing Cement Industry
Through the use of alternative fuels, carbon capture technologies, and energy-efficient practices, the industry can contribute significantly to global efforts to limit global warming.
Traditional cement production using coal or oil as fuel can release toxic pollutants such as heavy metals (e.g., mercury and lead). Decarbonizing cement production by switching to alternative fuels and improved emission controls can reduce the release of these harmful substances into the environment.
Decarbonizing the cement industry by adopting alternative fuels and renewable energy sources can reduce its dependence on fossil fuels.
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