Pablo Sánchez Álvarez

Using hydrogen in compression-ignition internal combustion engines can reduce pollutant emissions and improve performance by enabling faster and more complete combustion. However, it is essential to determine the optimal injection timing and duration for both hydrogen and conventional fuels. These factors are critical in engine modeling analysis. This study aimed to analyze pollutant emissions, combustion, and engine performance with oxyhydrogen fumigation applied to an instrumented Ricardo E6 engine running on diesel fuel. This analysis, necessary for developing a new predictive combustion model, was calibrated with experimental data in the Gamma Technologies Suite (GTS) simulator. The results show four main effects when increasing the oxyhydrogen flow rate from 0 to 2.8 L per minute (LPM), at an indicated mean effective pressure (IMEP) of 5.3 bar and a speed of 1500 RPM: (I) NO_x levels increased by up to 6%, (II) CO₂ levels decreased by 8%, (III) combustion durations remained relatively stable, and (IV) brake specific fuel consumption decreased by 8%. Overall, adding hydrogen to the intake flow of the compression-ignition engine reduced CO₂ emissions and enhanced indicated thermal efficiency.

Pollutant emissions into the atmosphere derived from port activities can be transported to surrounding regions and cities depending on wind speed and direction, having an impact on air quality. In this research, emissions of atmospheric pollutants (NOx, CO, NMHCs, CO₂, SO₂, TSP, PM_2.5 and PM₁₀) were estimated for: tanks, container, roll-on/roll-off (RO-RO), bulk carriers and general cargo ships, using emission factors in the hoteling and maneuvering stage in the port area of Veracruz, Mexico, during 2019 and 2020 despite the suspension period of activities due to the SARS-CoV-2/COVID-19 pandemic. Among the total estimated emissions, CO₂ presented the highest values for 2019 (31,177 kg/year) and 2020 (29,003 kg/year), whereas CH₄ presented the lowest values with 0.294 kg/year for 2019 and 0.273 kg/year for 2020. The highest estimated emissions for CO₂, NOx and SO₂ occurred in the maneuvering stage in 2019 for bulk carriers, tanks and container ships. Likewise, the highest estimated emissions were during the hoteling stage of the container ships in 2020. This study will provide an updated ship emissions inventory for the Gulf of Mexico region where the Port of Veracruz is located. In addition, SO₂ and PM_2.5 measurements were performed from October 2019 to December 2020. PM_2.5 concentrations exceeded the Mexican Ambient Air Quality Standard (MAAQS) value of 45 µg m⁻³ for the 24-h average concentration several times, on the opposite, SO₂ exhibited concentrations up to 20 times lower than the 24-h MAAQS value of 40 ppb. Results showed that pollutant emissions in the port of Veracruz exhibited a seasonal variability, modifying their dispersion and the possible effects. Our main conclusion is that current port area is the major source of pollutant emissions (SO₂ and PM_2.5) throughout the year, whereas the expansion area of the port of Veracruz does not represent still a significant rise of pollutant emissions, but it is expected that the growth of port activity will directly increase the concentrations of pollutants emitted.

The early fault detection and reliable operation of lithium-ion batteries are two of the main challenges the technology faces. Here, we report a new methodology for early failure detection in lithium-ion batteries. This new methodology is based on wavelet spectral analysis to detect overcharge failure in batteries that is performed for voltage data obtained in cycling tests, subjected to a standard charge/discharge protocol. The main frequencies of the voltage temporal signal, the harmonic components in the regular cycling test, and a low frequency pattern were identified. For the first time, battery failure can be anticipated by wavelet spectral analysis. These results could be the key to the new early detection of battery failures in order to reduce out-of-control explosions and fire risks.

One of the basic needs for a country’s economic development is to cover the major fuel demand, and both energy consumption and environmental impacts resulting from the production of such fuels need to be fast and reliable. The purpose of this paper is to contribute to an estimate of energy consumption and atmospheric emissions of some of the pollutant species reported by Pemex Refinacion under different projections. The predictive estimate model was applied considering four different gasoline demand scenarios, as well as different refining technology options to satisfy fuel consumption needs, based on production yields: four different types of refineries, three types of crude oils and eight different processes. Emission estimates were determined applying emission factors, both for the type of fossil fuel energy source used in the direct heating processes for vapor generation, as well by using electric energy. Results show that the equivalent energy consumption relative to the total processes crude is greater in complex refineries (full conversion); however, a greater conversion efficiency allows a smaller volume of crude consumption needed to satisfy the fuel demand with lower emissions relative to other types of technologies. Mexico’s possible refineries need to adapt themselves to different operation scenarios, such as changes in the crude’s yield, the quality of the product, variations in the prices of the crude and of the refined products. Therefore, is important to develop and apply perspectives than maximize productivity and minimize energy consumption, reducing air emissions, in constant change scenarios. Finally, the problem would then be evaluating which would be more convenient to obtain a greater socio-economic benefit: reduce emissions to the atmosphere or to lower operation costs of the refinery.

Ingeniería Investigación y Tecnología es una publicación trimestral, arbitrada, de investigación científica y tecnológica editada e impresa por la Facultad de Ingeniería de la UNAM. Su propósito es difundir información y conocimientos originales e inéditos relacionados con la ingeniería. Es un espacio para profesores, investigadores, profesionales y estudiantes de todo el mundo.