The use of waste limestone from paint shops for flue-gas desulfurization

Recently, there has been growing pressure for the secondary use of otherwise waste materials. The thermal and energy recovery of these materials, for example in existing heating plants, is also increasingly being discussed. An example of where it is worthwhile to look for such raw materials is in industrial zones around heating plants. This paper deals with the use of waste limestone from the paint shop of an automotive factory for desulfurization by the dry additive method in the adjacent combined heat and power plant. It provides a detailed laboratory description of the reference and contaminated materials, a field test on a boiler of an industrial partner, and the formulation of conclusions. The laboratory analysis described the difference based on organic content in waste limestone, especially 7.02% wg of combustible (ref. 0% wg), higher content of H (0.36 vs 0% wg) and C (9.13 vs 9.41% wg) and thermal decomposition of organic matter between 300-550 degrees C. There is also an indication of an additional content of Ti (0.48% g) and Ba (0.46% g). The test in commercial heating plant boilers shows similar waste and reference limestone consumption (2.67 against 2.76 kg<middle dot>kgSO2-1) in desulfurization technology with the same level of efficiency. This utilization generates 30.6% of economic savings.