Hydrogen feed concentration

These observations reinforce the hypothesis that such phenomena are a direct consequence of capacitances within the solid catalyst phase with a response time of the order of several minutes. In an attempt to better understand this unexpected behavior, another series of unsteady-state experiments was conducted with Catalyst I. A step increase in hydrogen feed concentration showed an overshoot in the instantaneous ethylene concentration followed by a very slow approach to steady-state (see Figure 4). 

Autoclave Results - Solvent Activity Test. The initial microautoclave work was done with tetralin and methylnaphtha-lene, using Indiana V bituminous coal (Table I). Base line data is shown in Figure 4. All three tests, Kinetic, SRT, and Equilibrium, show an increase in coal conversion with an increase in the concentration of tetralin. The Equilibrium Test shows the highest coal conversion of approximately 86 wt% of the MAF coal (based on the solubility in the tetrahydrofuran) at the 50% tetralin concentration. The Kinetic Test shows lower coal conversion. The hydrogen transferred to the coal from the tetralin in the Equilibrium Test at the 50 wt% tetralin feed concentration is approximately 0.5 wt% of the MAF coal. In the Kinetic Test 50 wt% tetralin feed concentration results in a much smaller transfer at the short reaction time of 10 minutes. 

Fig. 14.17 Relative current density for various anode compositions as a function of increasing CO concentrations added to a pure hydrogen feed to the anode / re = 840 mA cm-2, at 0.5 V, for platinum/carbon.

The apparent orientation of insect stylets to the vascular bundles caused by hydrogen ion concentrations was first reported by Fife and Frampton ( ). The leafhoppers fed mainly in the phloem tissue, which had a substantially higher pH than the surrounding plant cells. Other discriminating criteria for phloem-feeding insects have been indicated, including carbohydrate concentration (10) and positive hydrostatic pressure (11). 

Catalytic hydrogenation in supercritical carbou dioxide has been studied. The effects of temperature, pressure, and CO2 concentration on the rate of reaction are important. Hydrogenation rates of the two double bonds of an unsaturated ketone on a commercial alumina-supported palladium catalyst were measured in a continuous gra-dient-less internal-recycle reactor at different temperatures, pressures, and C02-to-feed ratios. The accurate control of the organic, carbon dioxide, and hydrogen feed flow rates and of the temperature and pressure inside the reactor provided reproducible values of the product stream compositions, which were measured on-line after separation of the gaseous components (Bertucco et al., 1997). 

Alkanolamines. Gas sweetening, ie, removal of hydrogen sulfide and carbon dioxide, using alkanolamines was patented in 1930. Several amine solvents are available as of the mid-1990s. The most widely used are monoethanolamine [141-43-5], diethanolamine [111-42-2], diglycolamine [929-06-6], and methyldiethanolamine [105-59-9]. Amine processes are generally applicable when hydrogen sulfide concentration in the feed gas is relatively low (eg,... 

The other commercialized pentane isomerization process is that of the Standard Oil Co. (Indiana) (20). This process differs from the Indiana-Texas butane process in that the aluminum chloride is introduced as a slurry directly to the reactor and that about 0.5% by volume of benzene is added continuously in the feed to suppress side reactions. Temperature, catalyst composition, space velocity, and hydrogen chloride concentration are generally similar to those in the corresponding butane process, but the reactor pressure is about 100 pounds lower. The Pan American Refining Co. operated the Indiana pentane isomerization process commercially during the last nine months of the war and produced about 400 barrels of isopentane per calendar day. 

The experimental results obtained with these reactors are summarized in Table I. Both reaction temperature and the molar ratio of propane to oxygen in the feed were kept constant at 430°C. and 3, respectively, while residence time was varied from 5 to 15 sec. Each experimental run was continued for about 4 hours. The hydrogen peroxide concentration in the liquid product sample was frequently checked by titration during the run. After the constant analytical value was attained, the products were subjected to the analytical procedure described before for obtaining the data given in the table. 

Figure 11.7 Demonstration of coupled transport. In a two-compartment cell, copper flows from the dilute (feed) solution into the concentrated (product) solution, driven by a gradient in hydrogen ion concentration [9], Membrane, microporous Celgard 2400/LIX 64N feed, pH 2.5 product, pH 1.0...

After about 170 min, most of the aniline has been consumed (plot at the bottom of the left column in Fig. 4.41). The hydrogen concentration increases (which increases reactor pressure and reduces the hydrogen feed) and the reaction rate slows (which reduces the heat generation). The reactor temperature drops, cutting the cooling water. The batch is stopped when the conversion of aniline reaches 99.9% at 214 min. 

The mechanism of the catalyst activation by sulfur is not understood. The amount of sulfur compounds necessary to maintain or increase the catalyst activity depends in some cases on the stability of the heavy-metal sulfide component of the catalyst. Thus molybdenum sulfide seems to require a higher hydrogen sulfide concentration than tungsten sulfide. However, some catalysts that do not contain elements that can form sulfides under reaction conditions also showed an increased activity when sulfur compounds were added to the feed. Hydrogen sulfide in many cases decreases the catalyst sensitivity to nitrogen compounds and thus causes an activity increase. Sufficient data for pure compounds are not available to permit segregation of these effects. 

Vertical ammonia synthesizer at 300 atm with five cold shots and an internal exchanger (Fig. 19-22d). The nitrogen and hydrogen feeds are reacted over an Al203-promoted spongy iron catalyst. The concentration of ammonia is also shown in the figure. 

Step 4. Hydrogen feed comes from a header and toluene feed is drawn from a supply tank. The benzene, methane, and diphenyl products go to headers or tanks. Hence we are not constrained to set production either via supply or demand. From the kinetic expressions given previously, we see that only three variables could be potentially dominant for the reactor temperature, pressure, and toluene concentration. Pres-... 

The extraction of cobalt from arsenical concentrates consisting of autooxidation acid leaching under pressure, separation, purification, hydrogen reduction of ammoniacal leach solution, and removal of sulfur and granulation of the metal was described by Mitchell (M37). The final product contained 95.6% cobalt, 3.90% nickel, and 0.03% arsenic compared to the feed concentrate with an assay of 17.5% cobalt, 1% nickel, and 24% arsenic. 

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