Biodiesel methanol content
In 2008, Paraschivescu proposed a headspace solid phase microextraction (solid-phasemicroextraction, SPME), using two polydimethylsiloxane SPME fiber sampling, and then combined with the sample analysis by GC-FID. It is said that the method has good repeatability and recovery, and can be used to detect the content of methanol is extremely low standard method can not be analyzed.
This method uses 2- propanol as internal standard, the double column backblowing (a SE-54 capillary column, 2m * 0.32mm diameter for pretreatment, the other one is 25m * 0.20mm diameter OV-1 polar capillary column for analysis) method, divided into the analysis column to prevent restructuring. The instrument has the function of electronic flow control (EPC), which can realize the reverse blowing through the change of the pressure of the column.
However, in addition to the EN14214 standard in the flash point has been limited, but also specifically the quality of methanol should not be higher than 0.2%. In addition to using near infrared spectroscopy, size exclusion chromatography (i.e. GPC gel permeation chromatography) method can be used for the quantitative analysis of biodiesel in methanol, Li Changxiu proposed a GC-FID method, to determine the quantity of methanol in biodiesel.
Determination of methanol in biodieselIn the transesterification reaction, the reaction of methanol is very large. The biodiesel obtained from the reaction is treated by water washing and distillation, but there is still a small amount of free methanol in the final product. The methanol in biodiesel can cause metal corrosion, mainly aluminum corrosion. ASTMD6751 indirectly limits the methanol content by setting the lower limit of flash point.
