2.2.3 Fuel properties determination
CP, CFPP, and PP are used to characterize the low-temperature flow properties of biodiesel fuels [19]. CP refers to the highest temperature where the cloudy crystals appeared in the sample fuel. PP corresponds to the lowest temperature where the sample fuels lose their fluid ability after cooling at a prescribed rate. CFPP is termed as the lowest temperature where a prescribed volume (20 mL) of sample fuel is no longer passing safely through the wire mesh filter within one minute. The PP, CFPP and CP of sample fuels were measured by using the SYP1022-2 multi-functional low-temperature tester (Shanghai Boli Instrument Co., Ltd., China) in accordance with the standard methods of ASTM D6371, ASTM D2500, and ASTM D97 [29-31], respectively. Additionally, other fuel properties, such as acid value (AV), oxidation stability (OS), flash point (FP), density (ρ) and kinematic viscosity (υ), were determined according to the standard methods that listed in Table 3.
Table 3 The selected standards and physico-chemical properties of BWCO and DDCL.