Gases, Volume 1, Issue 2 (June 2021) – 5 articles

Ground-level ozone is a secondary air pollutant that is formed by chemical reactions between precursors, including nitrogen oxides (NO_x) and hydrocarbon (HC). Highway traffic, which can be controlled by traffic operational strategies, is one of the main sources of atmospheric NO_x and HC. Managed-lane pricing is one of the popularly used freeway traffic management approaches, while its impacts on ground-level ozone-related vehicle emissions is, however, still unclear. This motivated the purpose of this research. A case study in Houston, USA indicates that, vehicles on managed lanes had fewer hard accelerations/decelerations and higher average speed, which resulted in higher per-vehicle emissions in grams/hour, while the total emissions of a vehicle were roughly comparable to what they would be on a general-purpose lane. Total daily NO_x and HC emissions per managed lane were 31.9%–42.6% of those per general-purpose lane. The weight ratios between HC and NO_x show that, the ground-level ozone formation of this area is hydrocarbon-limited. Full article

The standard nonlinear Schrödinger Equation (NLSE) is one of the elegant equations to find detailed information about the modulational instability criteria of dust-ion-acoustic (DIA) waves and associated DIA rogue waves (DIARWs) in a three-component dusty plasma medium with inertialess super-thermal kappa distributed electrons, and inertial warm positive ions and negative dust grains. It can be seen that the plasma system supports both fast and slow DIA modes under consideration of inertial warm ions along with inertial negatively charged dust grains. It is also found that the modulationally stable parametric regime decreases with $\kappa$. The numerical analysis has also shown that the amplitude of the first and second-order DIARWs decreases with ion temperature. These results are to be considered the cornerstone for explaining the real puzzles in space and laboratory dusty plasmas. Full article

Clean, more responsible energy production in gas turbine power plants is a challenge. Interestingly, various alternative sources could be found in agricultural locations with great potential of being transformed from agricultural waste to energy. Corn cob gasification gas could be successfully implemented in gas turbines through co-firing with natural gas. Concurrently, agricultural biogas could also be employed for such a purpose. The technology could be implemented in locations such as Vojvodina, Serbia, which is an agricultural region with great potential for producing biogas from agricultural waste. Therefore, this paper approaches the practical implementation of gas produced by adiabatic corn digestion with CO₂ recirculation. Five different cases were assessed. The results are compared to previous analyses that used co-firing of the corn cob gasification gas in representative gas turbine systems. Impacts of the fuel composition on the characteristics of combustion were analyzed using CHEMKIN PRO with GRI–Mech 3.0. Impacts of fuel quality on the power plant performance were analyzed through calculations with a numerical model based on a Brayton cycle of 3.9 MW power output. The application shows acceptable values during co-firing with natural gas without modification of the overall system, with better outlet parameters compared to pure corn gasification gas. Full article

Time mismatch between renewable energy production and consumption, grid congestion issues, and consequent production curtailment lead to the need for energy storage systems to allow for a greater renewable energy sources share in future energy scenarios. A power-to-liquefied synthetic natural gas system can be used to convert renewable energy surplus into fuel for heavy duty vehicles, coupling the electric and transportation sectors. The investigated system originates from power-to-gas technology, based on water electrolysis and CO₂ methanation to produce a methane rich mixture containing H₂, coupled with a low temperature gas upgrading section to meet the liquefied natural gas requirements. The process uses direct air CO₂ capture to feed the methanation section; mol sieve dehydration and cryogenic distillation are implemented to produce a liquefied natural gas quality mixture. The utilization of this fuel in heavy duty vehicles can reduce greenhouse gases emissions if compared with diesel and natural gas, supporting the growth of renewable fuel consumption in an existing market. Here, the application of power-to-liquefied synthetic natural gas systems is investigated at a national level for Italy by 2040, assessing the number of plants to be installed in order to convert the curtailed energy, synthetic fuel production, and consequent avoided greenhouse gases emissions through well-to-wheel analysis. Finally, plant investment cost is preliminarily investigated. Full article

Natural gas plays an important role in energy supply, and its fields of application are diverse. However, the world’s largest growth potential among fossil fuels is attributed to liquefied natural gas (LNG). In the last few years, the U.S. rapidly increased LNG exports, and it is expected that they will further increase the liquefaction capacities. The cost of the LNG value chain is composed of the natural gas price in the country of origin, and the LNG process costs for liquefaction, transportation, storage, and regasification. Thus, the Henry Hub (HH) price in the U.S. is important for U.S. LNG exports to Western Europe. In this paper, gas flows in Western Europe at the beginning of the 2030s are analyzed if the price at HH is higher or lower than expected. Furthermore, the effect of the HH price on monthly U.S. LNG exports are studied. For the calculations, the global gas market model WEGA is used. The results reveal that the price at HH has a significant effect on annual gas flows in Western Europe and also on U.S. LNG exports during the summer. Furthermore, it is shown that pipeline gas in Western Europe will absorb fluctuations of U.S. LNG exports between the presented scenarios. Full article