Methane injection

Methane injection. Methane was chosen as a tracer, because... 

S. W. Reeve, W. A. Weimer, and D. S. Dandy, Diamond growth using remote methane injection in a direct current arc jet chemical vapor deposition reactor, Appl Phys. Lett., 63(18) 2487-2489 (1993)... 

The fact that methane injected into the PEDU decomposes to a certain extent suggests that methane formed directly from coal could also decompose. Thus the methane yield predicted by Equation 3 would have to be modified as in Equation 5. This gives the following equation for methane yield ... 

Methane injection into a nitrogen plasma jet leads to the following reaction ... 

Interestingly, an effective cooling method would be an endothermic reaction inside or on the outer surface of the blades. Unpublished work in the mid-1990s by scientists working in Israel has shown that this could become an acceptable technique - tests with methane over a nickel catalyst suggested that blades could be cooled by up to 300°K more than using conventional techniques. In this case the experiments were carried out with the catalyst on the outside of the blade, with methane injected into the boundary layer. The idea to use the endotherm to generate a useful product, however, was not considered, and for practical reasons it would be most convenient to have such a reaction inside the blade. 

Design point as well as off-design operation of the /x-fan can be modeled in a similar way to the compressor (see Sect. 5.3.3). The efficiency benefits of using a p-fan are relatively small. A better solution is to apply methane injection before the /x-fan, which decreases the demand for electricity by about 9%. It delivers almost the same total efficiency of the SOFC-M. If the p-fan has higher adiabatic efficiency, marginally higher total efficiency can be achieved— the... 

The most common solvent employed is carbon dioxide gas, which can be injected between water spacers, a process known as WaterAlternating Gas (WAG). In most commercial schemes the gas is recovered and reinjected, sometimes with produced reservoir gas, after heavy hydrocarbons have been removed. Other solvents include nitrogen and methane. 

Still under vacuum but at higher pressure (typically KT mbar), the initially formed ions collide with neutral molecules to give dilferent kinds of ions before they are injected into the analyzer. As an example, at low pressure, methane gas (CH4) is ionized to give molecular ions (CH4 ) but, at higher pressures, these ions collide with other CH4 molecules to give carbonium ions (CH5+). 

Another hydrogenation process utilizes internally generated hydrogen for hydroconversion in a single-stage, noncatalytic, fluidized-bed reactor (41). Biomass is converted in the reactor, which is operated at about 2.1 kPa, 800°C, and residence times of a few minutes with steam-oxygen injection. About 95% carbon conversion is anticipated to produce a medium heat value (MHV) gas which is subjected to the shift reaction, scmbbing, and methanation to form SNG. The cold gas thermal efficiencies are estimated to be about 60%. 

A typical oxidation is conducted at 700°C (113). Methyl radicals generated on the surface are effectively injected into the vapor space before further reaction occurs (114). Under these conditions, methyl radicals are not very reactive with oxygen and tend to dimerize. Ethane and its oxidation product ethylene can be produced in good efficiencies but maximum yield is limited to ca 20%. This limitation is imposed by the susceptibiUty of the intermediates to further oxidation (see Figs. 2 and 3). A conservative estimate of the lower limit of the oxidation rate constant ratio for ethane and ethylene with respect to methane is one, and the ratio for methanol may be at least 20 (115). 

Flame or Partial Combustion Processes. In the combustion or flame processes, the necessary energy is imparted to the feedstock by the partial combustion of the hydrocarbon feed (one-stage process), or by the combustion of residual gas, or any other suitable fuel, and subsequent injection of the cracking stock into the hot combustion gases (two-stage process). A detailed discussion of the kinetics for the pyrolysis of methane for the production of acetylene by partial oxidation, and some conclusions as to reaction mechanism have been given (12). 

The materials of constmction of the radiant coil are highly heat-resistant steel alloys, such as Sicromal containing 25% Cr, 20% Ni, and 2% Si. Triethyi phosphate [78-40-0] catalyst is injected into the acetic acid vapor. Ammonia [7664-41-7] is added to the gas mixture leaving the furnace to neutralize the catalyst and thus prevent ketene and water from recombining. The cmde ketene obtained from this process contains water, acetic acid, acetic anhydride, and 7 vol % other gases (mainly carbon monoxide [630-08-0][124-38-9] ethylene /74-< 3 -/7, and methane /74-< 2-<7/). The gas mixture is chilled to less than 100°C to remove water, unconverted acetic acid, and the acetic anhydride formed as a Hquid phase (52,53). 

High temperature steam cools and eventually condenses as it propagates through the oil reservoir. To maintain foam strength as the steam cools, a noncondensible gas, usually nitrogen or methane, is often added to the injectant composition (196). Methods of calculating the optimum amount of noncondensible gas to use are available (197). 

In one study, a coarse-grained sand aquifer was injected with methane and oxygen to stimulate the production of methane monooxygenase (MMO) enzyme which is capable of degrading TCE (18). TCE, added at 60—100 )-lg/L, was degraded by 20—30%. Injected concentrations of methane and oxygen were approximately 20 mg/L and 32 mg/L, respectively. 

C. Oxygen and steam are also injected above the bed to increase carbon conversion and reduce yields of methane and other hydrocarbons. The freeboard 2one above the bed operates as much as 150 to 230°C above the bed temperatures (24). 

The ROD is similar to a cold feed stabilizing tower for the rich oil. Heat is added at the bottom to drive off almost all the methane (and most likely ethane) from the bottoms product by exchanging heat with the hot lean oil coming from the still. A reflux is provided by a small stream of cold lean oil injected at the top of the ROD. Gas off the tower overhead is used as plant fuel and/or is compressed. The amount of intermediate components flashed with this gas can be controlled by adjusting the cold loan oil retlux rate. 

The gas is routed through heat exchangers where it is cooled by the residue gas, and condensed liquids are recovered in a cold separator at appro.ximately -90°F. These liquids are injected into the de-methanizer at a level where the temperature is approximately -90°F. The gas is (hen expanded (its pressure is decreased from inlet pressure to 22.3 psig) through an expansion valve or a turboexpander. The turboexpander Lises the energy removed from the gas due to the pressure drop to drive a compressor, which helps recompress the gas to sales pressure. The cold gas f-)50°F) then enters the de-methanizer column at a pressure and temperature condition where most of the ethanes-plus Lire in the liquid state. 

Under these conditions the issuing gases contain some 9% of unreacted methane sufficient air is injected via a compressor to give a final composition of 1 3 N2 H2 and the air bums in the hydrogen thereby heating the gas to 1100°C in the secondary reformer ... 

B. Direct Injection of Steam, Air, Methane, Cooling Water, etc. Supply line pressure plus 5 psi to 15 psi. 

This system produces a steady laminar flow with a flat velocity profile at the burner exit for mean flow velocities up to 5m/s. Velocity fluctuations at the burner outlet are reduced to low levels as v /v< 0.01 on the central axis for free jet injection conditions. The burner is fed with a mixture of methane and air. Experiments-described in what follows are carried out at fixed equivalence ratios. Flow perturbations are produced by the loudspeaker driven by an amplifier, which is fed by a sinusoidal signal s)mthesizer. Velocity perturbations measured by laser doppler velocimetry (LDV) on the burner symmetry axis above the nozzle exit plane are also purely sinusoidal and their spectral... 

To test the validity of this hypothesis, a 30% solution of hydrogen peroxide, a good source of hydroxyl radicals, was injected into the reactor during photockalytic methane... 

After peroxide injection, conversion of methane increases fix)m -4% to -10%, methanol production increases 17 fold, and carbon dioxide increases 5 fold, along with modest increases in hydrogen and carbon monoxide. Introduction of hydroxyl radicals to the reactor leads to a greater fi action of product going to methanol as evidenced by methane conversion increasing 2.5 times, whereas methanol production increases 17 times. The increase in carbon dioxide is fiom "deep" oxidation of... 

To improve the evaluation of a water and gas pilot, tracers were injected in the gas phase at the beginning of the first two-gas injection periods. Per-fluoromethylcyclopentane and perfluoromethylcyclohexane were used. In laboratory studies, these compounds were shown to have a higher partitioning to the oil phase than did tritiated methane. This caused a minor retention of the tracer [518,1119],... 

In the above-mentioned method by Hodgeson el acifluorfen was determined by GC/ECD after the extraction with a 47-mm PS-DVB disk and derivatization with diazomethane. The conditions for GC/ECD were as follows column, DB-5 fused silica (30 m X 0.32-mm i.d., 0.25-p.m film thickness) He carrier gas velocity, 25 cm s (210°C), detector makeup gas, methane-argon (5 95), 30mLmin column temperature, 50 °C (5 min), 10°Cmin to 210 °C (5 min) and to 230 °C (10 min) injection port and detector temperature, 220 and 300 °C, respectively injection method, splitless mode. The recovery of acifluorfen from purified water, dechlorinated tap water and high humic content surface water fortified at 0.5-2.0 ug was 59-150% and the LOD was 25 ngL Acifluorfen after derivatization with various chlorofor-mates was also determined by GC/MS using an SE-54 column (25 m x 0.20-mm i.d., 0.32- um Aim thickness), and the average recovery of acifluorfen fortified between 0.05 and 0.2 ugL was 78%. ... 

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