Investigating the Use of Recycled Pork Fat-Based Biodiesel in Aviation Turbo Engines

This paper presents an analysis of the possibility of using recycled pork fat-based biodiesel as fuel for aviation turbo-engines. The analysis consists of the assessment of four blends of Jet A kerosene with 10%, 30%, 50%, and 100% biodiesel and pure Jet A that was used as reference in the study. The first part of the paper presents the physical-chemical properties of the blends: density, viscosity, flash point, freezing point, and calorific power. Through Fourier transform infrared spectroscopy (FTIR) analysis, a benchmark was performed on the mixtures of Jet A with 10%, 20%, 30%, 50%, and 100% biodiesel compared with Jet A. The second part of the paper presents the test results of these blends used for fuelling a Jet Cat P80 turbo engine at the Turbo Engines Laboratory of the Aerospace Engineering Faculty of Polyethnic University of Bucharest. These functional tests were performed using different operating regimes as follows: idle, cruise, intermediate, and maximum. For each regime, a testing period of around 1 min was selected and the engine parameters were monitored during the test execution. The burning efficiency was calculated for the maximum regime for all mixtures. To evaluate the functioning stability of the turbo engine using biodiesel, two accelerometers were mounted on the engine support that recorded the radial and axial vibrations. Moreover, to assess the burning stability and to identify other acoustic spectral components when biodiesel is used, two microphones were placed near the jet region. A comparative analysis between blends was made by taking the Jet A fuel as reference.

Synergistic Interactions During Cocombustion of Lignite, Biomass, and Their Chars

Woody biomasses such as ash tree (AT), hybrid poplar (HP), and rhododendron (RD) were subjected to torrefaction and carbonization at temperatures of 200 °C and 400 °C. Likewise, several lignite samples were carbonized at 750 °C. Various binary fuel blends such as raw lignite/raw biomass, raw lignite/biochar, lignitic char/raw biomass, and lignitic char/biochar were prepared where the fraction of biomass or biochar was 10 wt% in the blends. The cocombustion characteristics of these blends were investigated through a thermal analysis method from the synergetic point of view considering the fuel properties and the combustion performance. Some parameters relevant to the combustion reactivity such as ignition point, maximum rate, peak temperature, and burnout temperature were commented to figure out whether synergistic interaction or additive behavior governs the combustion characteristics of the blends. Also, the combustion performance indices such as ignition index (Ci), burnout index (Cb), comprehensive combustibility index (S), and the burning stability index (DW) were estimated. It was concluded that the combinations of the additive behavior and the synergistic interactions governs the cocombustion process, and the kind of the fuels and their thermal history determine the reactivity and the interactions during cocombustion.

Effects of Pretreatment Outside of Torrefaction Range on Combustion Characteristics of Chars From Lignocellulosic Biomass

Lignocellulosic woody biomasses such as rhododendron (RD), ash tree (AT), and hybrid poplar (HP) were heated under N2 at 200 °C and 400 °C, which are regarded as outside the range of efficient torrefaction temperatures. Also, several Turkish brown coals were carbonized at 750 °C for comparison. The obtained biochars/chars were characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and thermal analysis. Combustion reactivity of the raw samples and the chars was estimated using the burning profiles. Burning kinetics was established by the Borchardt and Daniels (B&D) kinetic analysis method that was based on the evaluation of the differential scanning calorimetry (DSC) data. Ignition index (Ci), burnout index (Cb), comprehensive combustibility index (S), and burning stability index (DW) were considered to evaluate the combustion performance. It was concluded that although treatment at 200 °C did not lead to considerable changes on the biomass structure, the combustion performance of the treated biomass became highly improved in comparison with the raw biomass. However, treatment at 400 °C led to serious variations in the biomass structure mainly due to reduction in O content and volatiles so that the fuel properties and the burning characteristics were affected, and the combustion performance was negatively influenced.

Burning Characteristics and the Fuel Properties of the Dry-Carbonization Chars of Sewage Sludge

As an alternative treatment to hydrothermal carbonization, sewage sludge (SS) was subjected to dry carbonization at temperatures of 200–700 °C to produce pyrochar. The fuel properties of the obtained chars were characterized, and their combustibility was checked by thermal analysis method. The combustibility of the chars was evaluated considering the criteria such as the ignition index (Ci), burnout index (Cb), comprehensive combustibility index (S), and the burning stability index (DW). Although even low temperature treatments such as 200 °C and 300 °C did not improve the calorific value, some improvements took place in the combustion characteristics upon treatment.