The effect of cetane improver on polyclic aromatic hydrocarbons in diesel exhaust

Abstract

The effect of cetane improver on quality and quantity of polycyclic aromatic hydrocarbons in diesel exhaust was studied by operating a diesel engine coupled with a dynamometer for laboratory test at different loads and speeds. PAHs in particulate phase and semivolatile phase from diesel exhaust were collected by glass fiber filter and polyurethane foam, respectively. Them they were extracted by soxhlet extraction and analysed by gas chromatography-mass spectrometry. PAHs found in diesel exhaust were naphthalene, methylnaphthalene, dimethylnaphthalene, acenaphthene, phenanthrene, methylphenanthrene, fluoranthene and pyrene. Addition of cetane improvers, 2-ethylhexyl nitrate and di-ti-butyl peroxide could reduce PAHs in diesel exhaust. For the engine load test, it was found that the amount of PAHs in diesel exhaust was lowest at 50% load and highest at 80% load, For the engine speed test, it was found that amount of PAHs in diesel exhaust at the engine speed of 2500 rpm was slightly higher than the engine speed of 1500 and 3500 rpm. The study has shown that supervising powers of the Minister of University Affairs over state and private universities vary in accordance with the subject matter and nature of institution under control. In many cases, there are discrepancies between the above mentioned Act and practices under the other Acts, which leads to confusion. More over, the research has pointed out that in regulating and supervising higher education in Thailand, there are many overlapping authorities i.e. Minister of University Affairs, Minister of Education and various professional associations. The study has recommended the amendment of various Acts in Line with the Act on Administration of Ministry of University Affairs, B.E. 2520 as amended in B.E. 2537.