Laser-driven calorimetry measurements of petroleum and biodiesel fuels

Abstract

Thermochemical characteristics were determined for several National Institute of Standards and Technology standard-reference-material petroleum and biodiesel fuels, using a novel laser-heating calorimetry technique. Measurements focused on the sample thermal behavior, specific heat release rate, and total specific heat release. The experimental apparatus consists of a copper sphere-shaped reactor mounted within a chamber, along with laser-beam-steering optical components, gas-supply manifold, and a computer-controlled data-acquisition system. At the center of the reactor, liquid sample is injected onto a copper pan substrate that rests and is in contact with a fine-wire thermocouple. A second thermocouple is in contact with the inner reactor sphere surface. The reactor is heated from opposing sides by a continuous-wave, near-infrared laser to achieve nearly uniform sample temperature. The change in temperature with time (thermogram) is recorded for both thermocouples, and compared to a baseline thermogram (without liquid in the pan). The thermograms are then processed (using an equation for thermal energy conservation) for the thermochemical information of interest. The results indicated that the energy reaching the pan is dominated by radiative heat transfer processes, while the dominant thermal process for the reactor sphere is the stored (internal) thermal energy within the sphere material. Sufficient laser power is necessary to detect the fuel thermal-related characteristics, and the required power can differ from one fuel to another. With sufficient laser power, one can detect the preferential vaporization of the lighter and heavier fuel fractions. The total specific heat release obtained for the different conventional and biodiesel fuels used in this investigation were similar to the expected values available in the literature.

Influence of diesel vehicles on the biosphere

“…Generally, biogas, bioethanol, and biodiesel fuel are con sidered as biofuel for transport. We considered environmental issues to apply biodiesel fuel for Vs. For instance, many re searchers believe that diesel engines have optimum ratios of size, weight, operational, environmental, power, and econom ic characteristics remaining an energy unit having no alterna tive for quite a long time [13].…”

“…To obtain equal amount of biodiesel energy, raw material crops should occupy three times more land than sugar cane to manufacture ethanol. Moreover, CO 2 emission in the process of raw material cultivation for biodiesel is 4-14 times higher than that one for bioethanol and biomethane [13]. The above mentioned is the significant obstacle preventing biodiesel fuel expansion [13].…”

“…Moreover, CO 2 emission in the process of raw material cultivation for biodiesel is 4-14 times higher than that one for bioethanol and biomethane [13]. The above mentioned is the significant obstacle preventing biodiesel fuel expansion [13]. Sunflower and rapeseed cultivation is much less efficient as for the biofuel amount obtained per hectare.…”