How Alternate Fuel Paves the Way to Sustainable Cement Production

Unless you’re way off the beaten track, you are within a couple of yards of some amount of cement. It’s one of the most widely used building materials globally. Without it we wouldn’t have the interstate, the Golden Gate Bridge, the Empire State Building, or Hoover Dam. Apart from these landmarks, cement also supports rural development through water management systems and essential facilities like hospitals. To put it succinctly, cement is indispensable.

Because of cement’s many uses, global production stands at a whopping 4.1 billion tons annually. Given its scale, cement production is an economic necessity and a major contributor to global CO₂ emissions. With all that taken into account, exploring ways to make this process more sustainable is hugely important.

Traditional Cement Production

Cement production typically involves at least five major stages:

1. Mining raw materials (like limestone and clay)
2. Grinding these into a fine powder
3. Heating them in a kiln to form clinker (an intermediate product)
4. Cooling and mixing clinker with gypsum
5. Grinding this into the fine powder known as cement

It’s easy to imagine why cement production is so energy-intensive. Kiln heating alone requires extremely high temperatures (up to 1,450°C). This scorching hot temperature is traditionally achieved by burning low-quality fossil fuels like coal or petroleum coke.

These dirty burning fuels make cement production expensive and environmentally damaging. Fossil fuel combustion releases significant amounts of CO₂, a major greenhouse gas. In fact, the cement industry accounts for approximately 8% of global carbon emissions. So how can the industry shift towards a new method of production?

Alternative Fuels

One promising approach is replacing fossil fuels with alternative ones made from recycled materials. This could reduce the industry’s carbon footprint while providing a solution for waste management. While there are many alternative fuels, two that are suitable for cement production are:

1. Biomass Residues: Organic waste materials such as agricultural residues, wood chips, and sawdust can be burned as fuel. These sources come from the waste of other construction projects and generally release less CO₂ than traditional fossil fuels.
2. Waste-derived Fuels: Used tires, industrial waste, plastic, and even municipal solid waste (MSW) can be converted into fuel for cement kilns. Tires are an especially hot burning waste product and cause problems in landfills. By repurposing them to make cement, the industry reduces its reliance on fossil fuels and diverts waste from landfills.

While it sounds like cheating to use garbage rather than extracted fuel to get the same job done, it may be a key intermediate step as the industry transitions to more renewable sources of energy. A lack of efficient ways to process things like tires and wood scraps into small fuel pellets has been a roadblock to using alternative fuels in the past. But with improvements in industrial waste shredders, all of that is changing.

Equipment Required for Producing Alternative Fuels

To convert waste materials into usable fuel for cement production, you need machines that can process various, non-uniform waste with the same ease that we eat Cheerios. Here are some examples:

1. Industrial Shredders: Shredders play a vital role in processing waste materials like tires, plastics, and MSW. They reduce these materials into smaller, manageable pieces that can be further processed. High-capacity shredders can handle various materials.
2. Drying Systems: Moisture content makes combustion less efficient. Drying systems, such as rotary dryers, reduce moisture levels in organic waste and other recyclable materials. This ensures the alternative fuel burns efficiently and produces consistent heat for the cement kiln.
3. Pelletizers: A uniform fuel burns more consistently than random-sized pieces. Pelletizers compress and bind shredded materials into dense pellets of the same size, for things like tires, granulators and filters achieve the same purpose.
4. Conveyors and Feed Systems: A reliable conveyance system is essential to integrate alternative fuels into the cement production line. These systems transport the processed fuels from storage areas to the kilns, ensuring a continuous and controlled feed.
5. Kiln Modification Equipment: Traditional cement kilns are designed for fossil fuels, so modifications are sometimes, but not always, necessary when switching to alternative fuels. Equipment such as multi-fuel burners and feeding systems are often installed to allow kilns to handle the diverse characteristics of different alternative fuels effectively.

Why Alternative Fuels Are Better than Fossil Fuels

Switching to alternative fuels from recycled materials offers several advantages over traditional fossil fuels:

1. Reduced Carbon Emissions: Using alternate fuels means less carbon dioxide is released from traditional fossil fuels.
2. Cost Efficiency: With price fluctuations and regulations tightening, the cost of traditional energy sources can be cheap one quarter and expensive the next. In contrast, alternative fuels are trending cheaper and cheaper.
3. Waste Management: By using materials like tires, plastics, and industrial waste, cement plants help manage waste that would otherwise end up in landfills or pollute the environment.

Investing in the right equipment, such as shredders, granulators and dryers can place you in the center of the decarbonization of cement production. By prioritizing these sustainable practices, the cement industry can continue to build the infrastructure we need without compromising the environment.