Beypiliç Chicken Slaughterhouse in Bolu, TURKEY. These animal fats are transformed into liquid form by a rendering process. The corn oil and chicken fat were liquid at room temperature while the fleshing oil was in solid state at room temperature.
The initial target for the pretreatment is to reduce the FFA level of feedstocks to less than 1%. Because the acid values of the animal fats used in this study were greater than 2 mg KOH g 1, it was needed to perform a pretreatment to the feedstocks. Due to low acid value of corn oil, it was directly subjected to transesterification via base catalyst. Some measured properties of the oils are shown in Table 1. The fatty acid compositions of the oils and methyl esters are given in Table 2, which are important for the determination of the mass balance in the process. According to fatty acid compositions of the feedstocks, the total saturated fatty acid compositions of corn oil, chicken fat and fleshing oil are about 14%, 27% and 42%, respectively. On the other hand, saturated fatty acid rates in the produced methyl esters remained almost the same when compared with the respective feedstocks.
2.1. Pretreatment and transesterification process in the pilot plant
The optimum reaction parameters of small-scale transesterification of feedstocks were used in a pilot scale biodiesel production from animal fats (Alptekin and Canakci, 2010, 2011; Alptekin et al., 2012). In addition, corn oil was used in pilot scale biodiesel production to compare the fuel properties of vegetable oil and animal fats methyl esters. The biodiesel pilot plant was assembled at the Alternative Fuels Research and Development Center in Kocaeli University.
Biodiesels were produced in the pilot plant with the capacity of about 100 kg per day. The schematic of the biodiesel pilot plant is shown in Fig.
1. The feedstock tank (200 l) has electrical heaters to prevent solidification of feedstock especially for fleshing oil. All the feedstocks were filtered with 60-micron fuel filter before transferring to feedstock tank.
Sulfuric acid and methanol were used for the pretreatment of the fleshing oil and chicken fat. Certain amounts of the feedstock were transferred to main reaction (120 l) tank for pretreatment reactions. The feedstock was dried under vacuum to remove any potential water. The required amount of alcohol was transferred from the alcohol tank (200 l) to methoxide tank (120 l). The acid catalyst was added to the tank manually. Methanol and catalyst were mixed in the tank named as methoxide tank. The reactant amounts differ from each other due to different FFA levels of the feedstocks and those will be mentioned in the next sections. The alcohol and catalyst mixture were stirred about 20 min in the methoxide tank and then it was transferred to the reaction tank when the temperature of the feedstock in the reaction tank