Assisting Alternative Fuel Adoption

As industries strive to reduce CO₂ emissions globally, the many facilities belonging to the cement industry have been using various alternative fuels and raw materials in their efforts to reduce CO₂ emissions.

Co-processing in cement manufacturing refers to the use of alternative fuels in both combustion and production processes. In terms of combustion, this means substituting primary fuels, such as coal, petroleum, and gas, with waste. This typically consists of combustible municipal waste or refuse-derived fuels, biomass, and non-hazardous industrial and commercial waste.

The second element of co-processing involves substituting part of the natural raw materials used in the production process (e.g. limestone) with ash residue from the combustion process.

Co-processing fuel

These materials are often from varied suppliers and different sources, where the real advantage of using alternative fuels lies in the lower CO2 emissions. The fuel feeds provide ash containing additional iron (Fe), calcium (Ca), silicon (Si), and aluminium (Al), which reduces the amount of raw limestone or secondary raw materials such as fly ash, slag, and pozzolans needed to produce clinker. One drawback may be the presence of toxic elements in these feeds.

In cement production, it is critical to identify and analyse solid waste as it arrives for sorting, shredding, and homogenisation before it enters the kiln to help ensure the waste is free of heavy metals and toxic substances. One tool that plays an important role in this process is the handheld X-ray fluorescence (XRF) analyser. To understand why handheld XRF is an essential testing tool for co-processing solid wastes in cement kilns, it is important to know how it fits into the overall process.

The technology for co-processing solid wastes in cement kilns was developed in the 1970s. Since the 20th Century, some countries have combined the concept of waste treatment with the circular economy and sustainable development.

By using cement kilns to treat solid waste, they can eliminate the operational costs of using solid waste treatment facilities and enable the use of alternative fuels and raw materials for cement production, achieving both environmental and economic benefits.

The core of co-processing solid wastes in a cement kiln lies in full utilisation of combustible components and ash materials in solid wastes or garbage during cement production. Combined with the production characteristics of a cement kiln, adopting the appropriate technical solution can help reduce garbage, eliminating its impact on the environment while turning it into a resource or energy source.

Regulators have set limitations on the content of heavy metal and other pollution elements in solid waste before it enters the kiln. Some important regulations include the environmental protection technical specification for co-processing of solid wastes in cement kiln (HJ 662-2013) and the technical specification for co-processing of solid wastes in cement kilns (GB 30760-2014).

To meet regulations and manage the co-processing of solid wastes, many cement manufacturers use handheld XRF analysers, such as the Vanta™ series, during the pre-treatment process. Manufacturers use this tool to test for both hazardous elements and toxic substances before solid waste enters the kiln.

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Read the article online at: https://www.worldcement.com/special-reports/19102022/assisting-alternative-fuel-adoption/