Fuel Communications最新文献

This work presents an experimental study on the thermal conductivity, viscosity, flash point and fire point of kernel palm oil methyl esters (KPOME) in the presence of conductive magnetic nanoparticles (FeO₃). The mass concentration of FeO₃ ranges from 0,10 wt% to 0,20 wt %. The parameters were determined from standard methods. ASTM D7896 for thermal conductivity (λ); ISO 3104 for kinematic viscosity (η), and ASTM D92 for flash point and fire point. The experimental results obtained show that the concentration with the best thermal conductivity between 40°C and 65°C is the 0,20 wt% representing sample 3 (E3). There is an improvement of 20,5% compared to the value of the base esters. On the other hand, between 80°C and 90°C, sample E1 of the concentration that constitutes the basic esters (KPOME) presents better results. A decrease of 49.5% compared to the value of the thermal conductivity of the KPOME is noted. The kinematic viscosity decreased with increasing temperature for all samples. Moreover, in the presence of iron oxide 3, this viscosity improves. The most significant improvement is obtained at 100°C with the 0,15 wt% concentration and the least significant is at 40°C for the 0,20 wt% concentration. The tests of flash point allow us to observe that there is a deterioration of this parameter in the presence of FeO₃ nanoparticles in the base bio-insulator (KPOME). The most significant deterioration comes from the sample with a concentration of 0,10 wt%. This means a variation from 155°C to 140,85°C; which gives a deterioration rate of 9,15%. However, the addition of iron nanoparticles rather improves the flash point compared to the base esters. The most important percentage improvement is that of the 0,10 wt% concentration which varies from 160°C to 165,97°C. This represents an improvement of 3,75%.

In this paper, a systematic method for determination of total sulfur in coal by ultraviolet fluorescence is established based on a self-developed large capacity combustion framework (LCCF). The simple oxidation-combustion mode is upgraded to the pyrolysis-oxidation-combustion mode with the help of LCCF. Thus, components to be analyzed is pyrolyzed slowly and the whole decomposition process of sample is prolonged, which could improve the consistence of test results. The sampling size to be sent into LCCF is significantly increased, and the representativeness of samples is secured, which promotes the improvement of accuracy of testing results. Detection limits are augmented without additional hardware or software improvements by this way. The test systems equipped with conventional combustion tube (CCT) and self-developed LCCF are established differently to test standard coal samples (SCS) and ordinary coal samples (OCS) with different total sulfur range. Accuracy and precision of the two test systems are tested and the optimal injection quantity of the system with LCCF is determined. The results show that LCCF could support the injection quantity of 1000mg and ensure stable and complete combustion of sample, which is far more than that of CCT. The accuracy and precision of the test results are better than the requirements of the existing conventional analysis standards, which shows the excellent structure of LCCF and good performance. The new analysis system can further expand the application of ultraviolet fluorescence method in field of coal and others.

Ammonia is considered a potential carbon-free alternative to fossil fuels. However, its unfavorable combustion characteristics and propensity to form fuel NO${}_x$ pose a challenge for its use as fuel for internal combustion engines. The high-pressure dual fuel (HPDF) direct-injection of ammonia could offer the potential to reduce ammonia slip and decrease NO${}_x$ formation. The feasibility of this combustion process has not yet been shown experimentally in literature. This work examines the ignition and combustion characteristics of diesel piloted liquid ammonia sprays under engine-relevant conditions in a rapid-compression-expansion-machine (RCEM). By examining heat release rates (HRRs) under a variety of spatial and temporal spray interaction configurations, charge conditions as well as different diesel pilot amounts and injection durations, the fundamental prerequisites for successful combustion of liquid ammonia sprays are revealed. Strong interaction of the two fuels is found necessary to properly ignite ammonia. Misfiring due to deterioration of the pilot mixture formation can be avoided by injecting diesel first. A strong correlation between main ignition delay and burnout rate suggests a significant influence of wall quenching effects. An investigation of less reactive charge conditions suggests poor suitability of the combustion process for low-load engine operation. While reliable ammonia ignition was achieved for diesel pilot amounts as small as 3.2% of the total injected LHV, ignition is increasingly delayed for smaller pilot amounts. For an operating point, which showed favorable ignition behavior and high conversion rates, pilot fuel amount and injection duration are found to have a major influence on the combustion process.

Ammonia has long been considered as a candidate vector for power generation, and has specifically gained significant interest recently. Though it is not free of drawbacks, ammonia has been identified as a promising potential alternative fuel for future power generation. Current studies and a growing body of works in this direction drive us closer to a viable solution of ammonia as an important transition into a cleaner future of the energy sector. In this perspective, we explore the use of ammonia as a fuel in combustion applications (with and without additives) and in fuel cells. The objective of this work is to show the prospects and challenges of ammonia as a fuel, and suggest significant topics that could benefit from additional studies.

This paper is a review of renewable energy potentials and energy usage statistics in Ghana. Principally, it covers Ghana's energy consumption from 2000 to 2020. The findings show that Ghana uses both renewable (10%) and non-renewable (90%) forms of energy, but biomass (46.667%) and oil (40.52%) are the commonly used energy resource. This is followed by natural gas (10%), hydroelectric power (7%), and solar energy (0%). The energy consumption by sector from 2000 to 2020 totaled up to 130632ktoe. Residents featured 62,736ktoe (48%) as well as industries, service, agriculture, and transport with each recording 18254ktoe, 5033ktoe, 1957ktoe, and 42652ktoe respectively. The review revealed that the energy demand of the country (Ghana) has shot up and therefore, there is the need for more sustainable energy alternatives to be employed in the energy processes of the country to offset the impacts of future energy crises.

In conventional gas turbine combustors, the combustion chamber linings are perforated and used for cooling. To cool the liner evenly, bias flows are introduced into the combustor at rates that depend on the operating condition. It has been found that airflow through the liner not only provides cooling but also improves sound absorption and acoustic instability. This experiment reports a unique comprehensive investigation of the influences of single and double-layer cylindrical full-scale gas turbine combustor liner sound absorption properties based on the no flow and non zero bias flows. In particular it is shown that combustor liner porosity (determined by orifice diameter and axial pitch distance) has an important influence on non-zero bias flow in that it increases the peak absorption or dissipation compared with that which occurs in the absence of flow. It is shown that the main influence of bias flow is to increase absorption compared with no flow above 600 Hz and to decrease the transmission loss measured in the absence of flow below 600 Hz but to increase it above 600 Hz. Internal resonance in the combustion liner test section influences both absorption and transmission loss spectra near 600 Hz. To create higher damping, and decrease in acoustic instability during the combustion process, gas turbine combustors require mapping between the inner and outer liner perforation to increase efficiency and lower the hydrocarbon emission. The calculated pressure ratio versus mass flow and combined discharge coefficient effect explain the non-linear distribution of the absorptive and dissipative energy measured at the gas turbine combustor.

Of all the types of renewable energy, Renewable Natural Gas (RNG) market has been more supported and developed in Canada due to the lower project cost and the existing NG pipeline infrastructure. RNG is defined as a methane-rich gas obtained through combining Anaerobic Digestion (AD) of underutilized renewable sources (organic waste streams) and upgrading technologies. Membrane separation technology is considered one of Canada's most popular upgrading technologies due to the country-old knowledge regarding gas permeation membranes widely used in the NG industry. Membrane systems are used to recover methane from biogas to a level that meets current natural gas pipeline specifications set out by gas utility companies or meets natural gas vehicle fuel standards set out by engine manufacturers. Here we review standards for gas injection into existing Canadian pipelines, commercial biogas upgrading systems in Canada, and Current biogas upgrading to RNG projects in Canada. We focus more on membrane technology and discuss the possible driving force, module, and configuration alternatives. Finally, this review comprehensively examines membrane types and advances in composite type membranes.

Although recent studies have shown the possibility of running ‘standard’ spark-ignition engines with pure ammonia, the operating range remains limited mainly due to the unfavorable characteristics of ammonia for premixed combustion and often requires the addition of a complementary fuel such as H₂ to extend it. As the best way to add H₂ is to crack ammonia directly on-board, this paper focuses on the impact of the upstream cracking level of ammonia on the performance and emissions of a single cylinder spark ignition engine. Experiments were performed over several equivalence ratios, dissociation rates and load conditions. It is confirmed that only a slight rate of ammonia dissociation (10%) upstream of the combustion considerably enhances the engine's operating range thanks to a better combustion stability. In terms of pollutant emissions, the partial dissociation of ammonia, especially for slightly lean mixtures induces a very clear trade-off between high NO_x and high unburned ammonia level for high and low ammonia dissociation rates, respectively. Therefore, cracking NH₃ does not only improve the operating range of ammonia-fueled spark ignition engines but can also help to reduce NH₃. However, to reach the same engine output work, higher ammonia fuel consumption will be necessary since the global system efficiency is lower using fuel dissociation. In addition, the global warming effect is increased with dissociation level since a higher level of N₂O is generated by the hydrogen contribution.