# Life Cycle Assessment of Different Waste Lubrication Oil Management Options in Serbia
## 3 Methodology
### WLO Treatment Scenarios in Serbia
#### 3.2.1 Incineration in Cement Kilns  
The use of alternative fuels in cement kilns has been present for over 40 years. Depending on legal regulations, environmental standards, and the price of available alternative fuels, the criteria for selecting alternative fuels in the cement industry are almost non-existent. Based on its internal standards, each of the cement producers sets certain criteria for selecting materials as an alternative fuel. These criteria are presented through several standards listed in the papers [32; 33]. Table 5 shows the use of alternative fuels in different countries of the world. Table 6 shows, in percentage terms, the most common types of waste used as alternative fuels in cement plants [34; 35]. As seen in Table 6, the use of oil in the cement industry depends on the manufacturer and the applied cement production technology. The Serbian cement industry consists of three cement plants owned by Lafarge-Holcim, CRH, and TITAN. The Lafarge-Holcim cement plant is the only cement plant in the country that boasts WLO processing technology. Of the other two cement plants, CRH uses Solid Recovered Fuel (SRF), whereas TITAN has not yet embarked on the process of using waste as alternative fuel and persists in using petroleum coke as a primary fuel. The share of alternative fuels used in the CRH and TITAN cement plants ranges up to 30% of the total amount of fuel used (including petroleum coke and coal), with an increasing trend until 2025 [36]. The share of WLO used in the Lafarge-Holcim cement production ranges up to 12% of the total amount of fuel used [31]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Country or Region** & **Substitution [\%]** & **Country or Region** & **Substitution [\%]** \\ \hline Australia (2013) & 7.8 & Germany (2010) & 53.6 \\ Japan (2012) & 15.5 & EU (2012) & 18 \\ Sweden (2011) & 45 & Poland (2010) & 45 \\ Switzerland (2012) & 41 & Spain (2011) & 22.4 \\ Nederlands (2011) & 85 & Belgium (2011) & 60 \\ Canada (2008) & 11.3 & USA (2004) & 8 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Use of alternative fuels in different countries or regions [30]. The available production capacity of the Lafarge-Holcim cement plant approximates to 1,500,000 t/year, or 1,200,000 t/year of linker. According to their public data, the Serbian cement plants use about 50% of their capacity per year. WLO accounts for about 12% of the total amount of fuel used annually in the Lafarge-Holcim cement plant for a cement production of 600,000 t/year. The Lafarge-Holcim cement production claims a 42.88% share of the total cement production in Serbia. Based on the data obtained [37], the consumption of WLO per ton of linker is 95 kg with a WLO net calorific value (NCV) of 35 MJ/kg. Moreover, the clinker ratio in cement production is 80% of the total amount, i.e., 0.8 kg of clinker is needed to obtain one kilogram of Portland cement. For the cement clinker production in Serbia, WLO is consumed in quantities up to 11.4 kg/t of clinker. Based on the data considered [31; 38], the consumption of WLO in the cement plants in Serbia varies depending on the amount of cement produced (assuming that the share of WLO is at a level of 12% of the total amount of fuels burned). The authors used the data shown in Table 4 to calculate the amount of oil burned in the Serbian cement plants (M\({}_{\text{BCKWLO}}\)). These values range from 37 to 69.26% depending on the amount of treated (regenerated) oils. The higher the percentage of burnt oils in cement plants, the less the amount of untreated oils. Table 7 shows the ratios of treated, untreated and burned WLOs in cement plants annually (on average).