Synthetic phenolic antioxidants to biodiesel: path toward NOx reduction of an unmodified indirect injection diesel engine


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Fattah I. M. R. , Hassan M. H. , Kalam M. A. , Atabani A. I. , Abedin M. J.

JOURNAL OF CLEANER PRODUCTION, vol.79, pp.82-90, 2014 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 79
  • Publication Date: 2014
  • Doi Number: 10.1016/j.jclepro.2014.05.071
  • Title of Journal : JOURNAL OF CLEANER PRODUCTION
  • Page Numbers: pp.82-90
  • Keywords: Antioxidant, Biodiesel, Coconut biodiesel, Performance, Emission, NOx reduction, EMISSION CHARACTERISTICS, COMBUSTION CHARACTERISTICS, EXHAUST EMISSIONS, PERFORMANCE, BLENDS, OIL, FUELS, SEPARATION, IMPACTS

Abstract

Biodiesel is a green alternative fuel produced from renewable resources. The major disadvantage of biodiesel is the substantial increase in NOx emission. This study examined the effects of antioxidant-treated coconut biodiesel on the performance and exhaust emission characteristics of an indirect injection diesel engine. Coconut biodiesel was produced by transesterification using potassium hydroxide as a catalyst. Two low-cost synthetic antioxidants, 2(3)-tert-butyl-4-methoxyphenol (BHA) and 2,6-di-tert-butyl-4-methylphenol (BHT), were added at 2000 ppm to 20% coconut methyl ester in diesel (CB20). Tests were conducted on a 55 kW 2.5 L four-cylinder diesel engine at a constant load varying speed. Results showed that the antioxidants significantly reduced NOx emission with a slight effect on brake thermal efficiency. The addition of BHA and BHT to CB20 reduced the average NOx emission by 7.78% and 3.84%, and the average brake specific fuel consumption by 1.77% and 1.46%, respectively. The antioxidant addition increased CO, HC, and smoke opacity, but the extent of increase was still below the diesel level. Thus, the addition of antioxidants presents a promising option for NOx reduction.

Biodiesel is a green alternative fuel produced froth renewable resources. The major disadvantage of biodiesel is the substantial increase in NO, emission. This study examined the effects of antioxidant-treated coconut biodiesel on the performance and exhaust emission characteristics of an indirect injection diesel engine. Coconut biodiesel was produced by transesterification using potassium hydroxide as a catalyst. Two low-cost synthetic antioxidants, 2(3)-tert-butyl-4-methoxyphenol (BHA) and 2,6-di-tert-buty1-4-methylphenol (BHT), were added at 2000 ppm to 20% coconut methyl ester in diesel (CB20). Tests were conducted on a 55 kW 2.5 L four-cylinder diesel engine at a constant load varying speed. Results showed that the antioxidants significantly reduced NOx emission with a slight effect on brake thermal efficiency. The addition of BHA and BHT to CB20 reduced the average NOx emission by 7.78% and 3.84%, and the average brake specific fuel consumption by 1.77% and 1.46%, respectively. The antioxidant addition increased CO, HC, and smoke opacity, but the extent of increase was still below the diesel level. Thus, the addition of antioxidants presents a promising option for NOx reduction. (C) 2014 Elsevier Ltd. All rights reserved.