Comparative profile of pollutants generated by a stationary engine fueled with diesel, biodiesel, and ethanol

Fossil fuel emissions derived from crude oil have a significant impact on the environment, climate change, air pollution, and others. Under these circumstances, there is a great interest in alternative energy resources, especially those that are able to reduce the emission of atmospheric pollutants. The aim of this study is to evaluate the burning emissions of the following binary mixture and biofuels: commercial diesel (diesel with 5% of biodiesel, B5), pure soy biodiesel (B100), additivated biodiesel (B100 adt) stored at 40 °C for 1, 2, and 3 weeks, and additivated ethanol (Ethanol adt). The burning emissions were evaluated by the levels of benzene, toluene, ethylbenzene, and xylenes (BTEX) and total particulate matter (TPM). The quality of the biofuels was given by oxidative stability during storage. The combustion products were originated from a diesel cycle stationary engine, operating in 1800 rpm and 0% load. For a greater reliability in the results, some figures of merit were evaluated for the determination of BTEX by gas chromatography and flame ionization detection (GC-FID) and the particulate matter was determined by gravimetric analysis. Results show that operating time of the engine influences combustion efficiency. During the initial 15 min, cold engine start, there was increasing in BTEX and TPM emissions, when comparing B100 and B5. Regarding to the storage period of 1-2 weeks, B100, B100 adt, and B5 showed reduction of approximately 36%, 16%, and 4% for TPM, respectively. Evaluating each component of BTEX, the benzene emissions were greater for biofuels, which is in agreement with previous studies. As observed for TPM, the storage time of 1-2 weeks was beneficial for the mitigation of aromatic emissions. A reduction about 60% percent was measured for benzene and ethylbenzene. However, these emissions can also be influenced by the engine operating conditions (load and speed), engine type, and characteristics of biofuels. Additivated ethanol also presented low emissions for these pollutants as well as the lowest percentage of emissions of TPM. It is noteworthy that Ethanol adt present the lowest percentage of benzene emission.