Cement Manufacturers Association (CMA)

23 average AFR usage (TSR) in the cement industry is far lower, nearly 4-5%. The selection criteria for alternative fuels are contingent upon the specific requirements of each cement production, considering factors such as process impact, product quality, and emissions. AFs are often either ingrade segregated wastes from industrial production or a combination of diverse wastes, most originating from municipal trash collection. Ingrade industrial wastes provide the benefit of pure ingredient homogeneity, but their availability must be close to the cement plant to avoid being consumed by logistical costs. Sources for municipal waste are often widespread so that this type of waste is usually better available for most cement plants. The disadvantage of municipal waste is that its consistency in its composition cannot be guaranteed, given the heterogeneity of its composition and its usually open-air storage. There is a need for controlling the chemical composition of the AF which is to be produced from municipal waste by pre-processing to meet regulatory requirements for environmental protection. The cement producer shall evaluate the following properties before using particular alternative fuels. • Pre-processing & proportioning properties, • Methods for segregation, • The emissions released, • Alternative fuels must be economically viable and readily available • Physical properties (scrap size, density, homogeneity, Moisture content) • Physical state of the fuel (solid, liquid, gaseous), • Content of circulating elements (Na, K, Cl, S), • Toxicity (organic compounds, heavy metals), • Composition and content of ash and content of volatiles, Calorific value • PCB content cadmium (Cd), thallium (Tl) and mercury (Hg), • The cement quality and its compatibility with the environment must not decrease. Industrial and municipal waste is available in all the countries. As a basic guideline, waste having an LHV greater than 10 MJ/kg fuel can be regarded as an alternative fuel. The table below shows the typical LHV for alternative fuels: Table 1: LHV and moisture of alternative fuels Description LHV(MJ/Kg) Moisture (%) Comments Waste oil, refinery waste 30 to 40 High grade Waste tires incl. steel and inerts 28 to 32 Mixed plastic waste material 20 to 28 10 RDF (from domestic source) 17 to 21 10 Medium grade Dried wood, bark 15 to 17 10 Grain straw 12 to 14 20 Low grade Rice straw 11 to 12 20 Dried sewage sludge 10 to 12 10 The list of available alternative fuels is mentioned below: • Gaseous sources include coke ovens, refineries, pyrolysis, and landfills. • Liquids include low chlorine spent solvents, lubricating oils, vegetable oils, fats, distillation residues, hydraulic oils, and insulating oils. • Solids that have been pulverized, granulated, or coarsely crushed, such as waste wood, sawdust, wood shavings, dry sewage sludge, used tires, and food residues. • Coarse crushed solids include plastic debris, discarded wood strips, and re-agglomerated organic matter. • Lumpy solids include scrap tires, plastic bales, bags, and drums. • Refuse-derived fuel with specific dimensions. Different alternative fuel needs different handling, preparation and dosing and has different impact on the process & quality.