نتایج جستجو برای: ch4 purification
تعداد نتایج: 63718 فیلتر نتایج به سال:
[1] Tropical East African Lake Tanganyika hosts the Earth’s largest anoxic freshwater body. The entire water column holds over 23 Tg of the potent greenhouse gas methane (CH4). Methane is formed under sulphate poor conditions via carbon dioxide reduction or fermentation from detritus and relict sediment organic matter. Permanent density stratification supports an accumulation of CH4 below the p...
This study aimed to evaluate the performance of the unified high-rate anaerobic digestion (UHAD) system treating co-substrate of sewage sludge and food waste. A 24-hr operating sequence consisted of four steps including fill, react, settle, and draw. The effects of co-substrate and organic loading rate (OLR) on the performance were investigated to verify the system applicability. In each OLR, t...
Kinetic and isotopic tracer methods led to a simple and unifying mechanistic proposal for reactions of CH4 with CO2 and H2O, for its decomposition on Rh clusters, and for water–gas shift reactions. Kinetic rates for forward reactions were measured by correcting net rates for approach to equilibrium and by eliminating transport artifacts. These rates were proportional to CH4 pressure (5–450 kPa)...
New facility-level methane (CH4) emissions measurements obtained from 114 natural gas gathering facilities and 16 processing plants in 13 U.S. states were combined with facility counts obtained from state and national databases in a Monte Carlo simulation to estimate CH4 emissions from U.S. natural gas gathering and processing operations. Total annual CH4 emissions of 2421 (+245/-237) Gg were e...
In contrast to other oligotrophic water bodies the Gulf of Mexico (GOM) hosts an abundance of hydrocarbon seeps, which likely influences the microbial assemblages it hosts particularly regarding the availability of labile carbon in the aphotic GOM. The aphotic zone receives direct injection of seep methane (CH4), but CH4 from an unknown source has been reported at supersaturated concentrations ...
[1] As natural sources of methane (CH4), peatlands play an important role in the global carbon cycle. Climate models predict that evapotranspiration will increase under a 2 CO2 scenario due to increased temperatures leading to lowered water tables at many northern latitudes. Given that the position of the water table within a peatland can have a large effect on CH4 emissions, climate change may...
The vast wetlands on the Tibetan Plateau are expected to be an important natural source of methane (CH4) to the atmosphere. The magnitude, patterns and environmental controls of CH4 emissions on different timescales, especially during the nongrowing season, remain poorly understood, because of technical limitations and the harsh environments. We conducted the first study on year-round CH4 fluxe...
The growth in global methane (CH4) concentration, which had been ongoing since the industrial revolution, stalled around the year 2000 before resuming globally in 2007. We evaluate the role of the hydroxyl radical (OH), the major CH4 sink, in the recent CH4 growth. We also examine the influence of systematic uncertainties in OH concentrations on CH4 emissions inferred from atmospheric observati...
Methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), and halocarbons are greenhouse gases (GHG) that are able to trap heat in the atmosphere by radiating less heat into the space and increase the effect of solar and thermal radiation on surface and atmospheric temperatures (Knapp et al., 2014). In 2014, total U.S. GHG emissions measured 6,870 million metric tons of CO2 equivalents. Agricul...
Natural variations in the tropospheric CH4 concentration, excluding short bursts from geospheric reservoirs, have been estimated for the past 400 Ma by scaling a wetland CH4 emission estimate for the middle Pliocene (ca. 3.6–2.6 Ma) by the relative rate of coal basin deposition at any given time in the past. Wetland CH4 fluxes were used as inputs into the Cambridge 2-D chemistry-transport model...
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