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The cement and lime industries are major contributors to the anthropogenic CO 2 emissions to the atmosphere. By combining the CO 2 -releasing calcination of CaCO 3 with the CO 2 -consuming dry-reforming of CH 4 , and by further combining these endothermic reactions with the exothermic partial oxidation of CH 4 , a single thermo-neutral process can be...
Nickel on zirconium-modified silica was prepared and tested as a catalyst for reforming methane with CO 2 and O 2 in a fluidized-bed reactor. A conversion of CH 4 near thermodynamic equilibrium and low H 2 /CO ratio (1<H 2 /CO<2) were obtained without catalyst deactivation during 10h, in a most energy efficient and safe manner. A weight loading of 5wt%...
Flue gases from coal, gas, or oil-fired power stations, as well as from several heavy industries, such as the production of iron, lime and cement, are major anthropogenic sources of global CO 2 emissions. The newly proposed process for syngas production based on the tri-reforming of such flue gases with natural gas could be an important route for CO 2 emission avoidance. In addition,...
Biogas composition and variation in three different biogas production plants were studied to provide information pertaining to its potential use as biofuel. Methane, carbon dioxide, oxygen, nitrogen, volatile organic compounds (VOCs) and sulphur compounds were measured in samples of biogases from a landfill, sewage treatment plant sludge digester and farm biogas plant. Methane content ranged from...
The production of aluminum by the electrolytic Hall–Héroult process suffers from high energy requirements, the release of perfluorocarbons, and vast greenhouse gas emissions. The alternative carbothermic reduction of alumina, while significantly less energy-intensive, is complicated by the formation of aluminum carbide and oxycarbides. In the present work, the formation of Al, as well as Al 2...
A newly developed microwave plasma system for fuel reforming was tested for three different hydrocarbon fuels. The microwave plasma system was powered by a low cost commercial magnetron and power supply. The microwave power was delivered to the nozzle from the magnetron via a coaxial cable, which offers tremendous flexibility for system design and applications. A non-premixed configuration was achieved...
The characteristics of controlled auto-ignition (CAI) were investigated with a methane–air mixture and simulated residual gas, that represents internal exhaust gas recirculation (IEGR). Supply systems were additionally installed on the conventional rapid compression machine (RCM), and this modified machine—a rapid intake compression and expansion machine (RICEM)—was able to simulate an intake stroke...
The rise in oil price triggered the exploration and enhancement of various renewable energy sources. Producing biogas from organic waste is not only providing a clean sustainable indigenous fuel to the number of on-farm digesters in Europe, but also reducing the ecological and environmental deterioration. The lignocellulosic substrates are not completely biodegraded in anaerobic digesters operating...
An experimental setup was established to measure the flammability limits of flammable gases at low temperatures. The flammability limits of methane/nitrogen mixtures in air were measured at atmospheric pressure and wide temperature range from 150 to 300 K. The estimated uncertainty of the experimental values was 0.2 vol%. The results reveal that as initial temperature decreases, the upper flammability...
Three groups of hydrate-bearing sediment samples with/without underlying gas were prepared using a three-dimensional middle-size reactor to investigate the favorable conditions for methane recovery from hydrate reservoir with gaseous CO 2 . The experimental results indicated that hydrate reservoir with underlying free gas, high saturation of free gas and low saturation of water is appropriate...
Ammonia is an important input into agriculture and is used widely as base chemical for the chemical industry. It has recently been proposed as a sustainable transportation fuel and convenient one-way hydrogen carrier. Employing typical meteorological data for Palmdale, CA, solar energy is considered here as an inexpensive and renewable energy alternative in the synthesis of NH 3 at ambient...
This paper presents the results of an experimental methane fermentation study on untreated, NaOH and hydrothermal pretreated substrates of wheat straw. Experiments were conducted at 37 °C (mesophilic temperature). Substrates concentration were maintained at 4.45% VS (44.5 g VS/L). Untreated wheat straw substrate had resulted into specific methane and biogas production yields of 78.4 L/kg VS a...
The world energy demand is foreseen to increase due to the improvements of the living standard in the developing countries and to the development of the global economy. The increase in sustainability of the energy supply must be considered as a must to avoid spoiling the natural resources, whose availability will be crucial for next generations. The CO 2 -free utilization of available energy...
The effects of the geometry of gliding-arc reactor – such as distance between the electrodes, outlet diameter, and inlet position – on the reactor characteristics (methane conversion, hydrogen yield, and energy efficiency) have not been fully investigated. In this paper, AC gliding-arc reactors including the vortex flow configuration are designed to produce hydrogen from the methane by partial oxidation...
In the present study the occurrence of volatile organic silicon compounds in biogas produced from grass silage, grass and maize in laboratory batch assays was analyzed and methane potentials were determined. Inoculum from a mesophilic farm digester was used, and its effects were subtracted. Methane yields from grass silage, grass and maize were 0.38, 0.42 and 0.34 m 3 CH 4 /kg – volatile...
A non-thermal plasma reforming unit operating at atmospheric pressure has been developed for converting methane to COx-free hydrogen. Argon was used to provide additional electrons and photons for higher reaction rates. A series of experiments was performed for positive corona discharge at a fixed inter-electrode distance (15 mm) to study the effects of discharge power (range of 14–20 W) and residence...
Semi-natural grasslands are characterized by high biodiversity and can be maintained only with continuous management. In current situation, without sufficient demand for these biomass as cattle fodder, this source can be used for bioenergy production. In Estonia the largest average annual dry biomass yield per area was achieved in alluvial meadows (5.5 t ha −1 ) and the lowest in wooded meadows...
Raw biogas is a valuable renewable energy but usually requires upgrading. The mixed LED (light-emitting diode) light wavelengths achieved much better microalgae growth than that of the monochromatic. The best LED light wavelength mix ratio for both biogas upgrading and biogas slurry nutrient removal was the red:blue ratio of 5:5. Lower influent CH 4 (methane) concentration achieved higher...
The detailed axial temperature variations of the porous media burner during startup and switch-off processes were experimentally measured and analyzed for the premixed methane air combustion. A tubular burner filled by alumina pellets with diameters of 10 mm and 4.3 mm, respectively, was used as the porous media burner to study the effect of the burner inlet gas flow rate, equivalence ratio, and diameter...
Identifying renewable energy alternatives in transport is particularly complicated, since the end-user can vary from a single-person car to a cargo ship. The aim of this paper is to aid this process by comparing 7 different methods for producing transport fuels in terms of the resources required, the conversion processes used, the fuel obtained, and the transport demand met. The results indicate that...
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