Gaseous Contaminant Emissions as Affected by Burning Scrap Tires in Cement Manufacturing

Abstract

We studied the environmental impact (gaseous emissions) of using scrap tires as a fuel substitute at a cement plant that produces one million tons of cement per year. Using a combination of tires and coal as opposed to only coal caused variations in the pollutant emission rate. The study recorded a 37% increase in the rate of emission for CO, a 24% increase for SO2, an 11% decrease for NOx, and a 48% increase for HCl when tires were included. The rate of emission for metals increased 61% for Fe, 33% for Al, 487% for Zn, 127% for Pb, 339% for Cr, 100% for Mn, and 74% for Cu, and decreased 22% for Hg. On the other hand, the emission rate of organic compounds dropped by 14% for polycyclic aromatic hydrocarbons, 8% in naphthalene, 37% in chlorobenzene, and 45% in dioxins and furans. We used a Gaussian model of atmospheric dispersion to calculate the average pollutant concentration (1-h, 24-h, and annual concentrations) in the ambient air at ground level with the help of the ISC-ST2 software program developed by the USEPA. When tires were used, we observed (i) a 12 to 24% increase in particulate matter, this range considering the concentration variation depending on the average used (1-h, 24-h, and annual basis), 31 to 52% in CO, 22 to 34% in SO2, 39 to 52% in HCl, 12 to 27% in Fe, -3 to 8% in Al, 30 to 37% in Zn, and 270 to 885% in Pb; (ii) a decrease of 8 to 13% in NOx, 9 to 13% in polycyclic aromatic hydrocarbons, 6 to 7% in naphthalene, 32 to 39% in chlorobenzene, and 32 to 45% in dioxins and furans. The results obtained showed that the maximum ground-level concentrations were well within the environmental standards (for operation with only coal as well as for operation with a combination of coal and tires).

Organic and inorganic pollutants from cement kiln stack feeding alternative fuels

“…Other authors [18] reported a 37% increase in the rate of emission of CO when using a combination between tyres and coal, a 24% increase in SO 2 and a 11% decrease for NO x . Nevertheless, the authors indicate a decrease of the rate of emission of organic compounds that is 45% for dioxins and furans.…”

Determination of heavy metals in surface soils around the brick kilns in an arid region, Iran

“…Some of the researchers found that pollutant emissions vary according to type of kiln; fuel used and kiln operating conditions and local meteorological conditions (Rajarathnam et al, 2014). For example emissions for some pollutants were found to be higher when coal was used as the main kiln fuel rather than petroleum coke (Zemba et al, 2011), or Carrasco et al (2002 found increased metals emissions when co-firing scrap tires, but decreased PCDD/Fs emissions. If we even assume that this hypothesis is true for our study, but we have no comparative data to examine the incremental effects (if any) of fuel used.…”

Monitoring air pollution close to a cement plant and in a multi-source industrial area through tree-ring analysis

“…In addition to the potentially harmful combustibles mentioned above, spent tires have been also used as fuel in the cement plant (as reported in Caldiroli 2015). According to Carrasco et al (2002), the use of spent tires in cement manufacturing cause an increase of emissions of S (SO 2 , + 24%) and heavy metals such as Zn (+ 487%) and Mn (+ 100%). In Cs, Mg, Mn and Zn, a maximum peak of level was found in 2013-2014, followed by a slight reduction in 2015-2016.…”