Magnesium/air combustion at pilot scale and subsequent PM and NO x emissions

Abstract

Fossil fuel scarcity, global warming and non-constant energy production through renewable energies (wind turbines and photovoltaic cells for example), lead to investigate innovative energy sources and new ways for energy storage. In the present study, magnesium powder has been considered as a new possible energy source. In order to analyze more deeply the magnesium combustion and the generated by-products, short time stable magnesium/air flames have been realized in a combustion chamber using an oxyacetylene flame for ignition. Sieved magnesium samples with two fractions were combusted: 20-50 µm and 50-70 µm. The power delivered by the Mg/air flame was estimated in the range 3-5 kW. The gaseous emissions (O2, CO2 from oxy-acetylene combustion, NO and NO2) were analyzed with on-line analyzers and the particulate emissions were analyzed with an Electrical Low Pressure Impactor (ELPI).The mass concentration of emitted particles whose size is smaller than 10 µm was proved to be very high (up to 35 g/Nm3) and the emitted particles were mainly bigger than 1 µm (84 to 97 wt%). NOx emissions were higher for the 20-50 µm Mg fraction (NO average of 4300 ±200 mg/Nm 3 ) than for the 50-70 µm Mg fraction (NO average of 1100 ±140 mg/Nm 3 ).

Pulverized Sponge Iron, a Zero-Carbon and Clean Substitute for Fossil Coal in Energy Applications

“…This observation suggests that implementing a retrofit metal fuel cycle might also alleviate adverse environmental effects typically attributed to NO x and SO 2 emissions, such as acid rain, atmospheric particulate matter, and the reduced concentration of tropospheric ozone . Furthermore, the emission of NO x from PSI combustion was much lower compared to the NO x emission of 125 ± 16 mg/MJ recalculated by us from the reported value of 1100 ± 140 mg/Nm 3 (O 2 percentage in flue gas of ∼9%) for magnesium combustion in air, indicating that PSI is also a superior fuel with respect to NO x emissions.…”

“…Benefits of metal powders as energy carriers over liquid H 2 can include secure handling and less stringent safety requirements. 6 Among possible metal fuel candidates (e.g., aluminum, 9 magnesium, 10 and lithium 11 ), iron has been suggested as the optimal carrier because it is thought to combust in a solid state without forming any metal vapor, gaseous oxides, or nanoparticles; 6 hence, the resulting combustion products are easily separable, and a micrometer-sized oxide fraction can be recovered from the product stream. Another significant benefit of using iron as an energy carrier is that reduction technology is already commercially available; for example, the DR process that converts iron ore in the form of fines, pellets, or sinter into sponge iron at a temperature well below the melting point of the iron itself 12 held a share of 73 Mt of global iron production in 2016.…”

Discharge Behavior of Water-Activated Magnesium Battery

“…Finally, we consider that the recent attention of WAMB comes from aspects other than poweroriented issues, that is, the convenience and safe handling, or expectations of Mg as an energy carrier for a sustainable society [38]. Apart from LED lamps, water sensors from diapers [39] to underground pipelines [40], biodegradable batteries for medical implants or home appliances [41,42] can be expected as new applications of WAMB.…”

Metal fuel production through the solar carbothermal reduction of magnesia: effect of the reducing agent

“…7 They published several studies investigating the combustion of metal fuels in a burner under a stable flame, the improvement of the burning time and the collection of metal oxide to regenerate them. 8,9 An innovative power generation system where 50-70 μm magnesium particles are combusted in a swirledstabilized metal-air burner has been developed in a collaborative work between STELLANTIS and LGRE-UHA 10 and 98% of the produced submicron magnesia particles are trapped and collected. 11 This system proved to have an optimal heat-to-mechanical conversion efficiency where 80% of the power generated from combustion is recovered in the power generation system.…”