Reactor oxygen treatment

The purpose of this paper is to examine how exposure of a "reactor equilibrated" catalyst to different gas phase oxygen treatments influences the selectivity and rate of n-... 

Nickel Reactor. The nickel reactor exhibited a peculiar initial activity profile after the walls had been treated with oxygen. The same peculiar profile was always obtained regardless of the oxygen treatment temperature or duration. Figure 7 shows that the activity of walls dropped steadily in the first 15 minutes of the run, then suddenly the wall activity increased sharply over the next 25 minutes as indicated by the sharp increases in hydrogen and methane yields. Propylene conversion also increased by 30% during that 25 minute period. A sharp decrease in activity then followed and a steady state activity level was finally reached after 90 minutes of run. 

Reactor surfaces which are treated with oxygen produced strong surface effects. However, the level of activity of the oxidized surface as compared to that of the untreated surface depends largely on the type of metal or alloy. The initial activity of 304 stainless steel, incoloy, and inconel increased after oxygen-treatment of the surface. 

The Strong surface effects observed after oxygen treatment of the reactors are probably caused by oxygen adsorption and/or reaction of the oxygen with the reactor walls to form complex metal oxides. Transformations in the structure of these oxides can occur due to change in temperature, exposure to a reducing atmosphere, or attack by another chemical such as hydrogen sulfide. 

After each hydrogen sulfide treatment of the stainless steel reactor, oxygen was passed through the reactor and Initially most of the oxygen was adsorbed on the reactor surface. For example, the Inlet flow rate of oxygen was adjusted to 13 cc/mln. after the second hydrogen sulfide treatment Initially the outlet flow was almost zero for about 50 minutes. Subsequently, the exit flow Increased In amount during the next three hours, and the... 

The Fischer-Tropsch reaction is essentially that of Eq. XVIII-54 and is of great importance partly by itself and also as part of a coupled set of processes whereby steam or oxygen plus coal or coke is transformed into methane, olefins, alcohols, and gasolines. The first step is to produce a mixture of CO and H2 (called water-gas or synthesis gas ) by the high-temperature treatment of coal or coke with steam. The water-gas shift reaction CO + H2O = CO2 + H2 is then used to adjust the CO/H2 ratio for the feed to the Fischer-Tropsch or synthesis reactor. This last process was disclosed in 1913 and was extensively developed around 1925 by Fischer and Tropsch [268]. 

Although acetic acid and water are not beheved to form an azeotrope, acetic acid is hard to separate from aqueous mixtures. Because a number of common hydrocarbons such as heptane or isooctane form azeotropes with formic acid, one of these hydrocarbons can be added to the reactor oxidate permitting separation of formic acid. Water is decanted in a separator from the condensate. Much greater quantities of formic acid are produced from naphtha than from butane, hence formic acid recovery is more extensive in such plants. Through judicious recycling of the less desirable oxygenates, nearly all major impurities can be oxidized to acetic acid. Final acetic acid purification follows much the same treatments as are used in acetaldehyde oxidation. Acid quahty equivalent to the best analytical grade can be produced in tank car quantities without difficulties. 

Oxygen is used in these microbiolreactions to degrade substrates, in this case organic wastes, to produce energy required for ceU synthesis and for respiration. A minimum residual of 0.5 to 2.0 mg/L DO is usually maintained in the reactors to prevent oxygen depletion in the treatment systems. 

AVT Barg BD BDHR BF BOF BOOM BOP BS W BSI BTA Btu/lb BW BWR BX CA CANDUR CDI CFH CFR CHA CHF CHZ Cl CIP CMC CMC CMC COC All-Volatile treatment bar (pressure), gravity blowdown blowdown and heat recovery system blast furnace basic oxygen furnace boiler build, own, operate, maintain balance of plant basic sediment and water British Standards Institution benzotriazole British thermal unit(s) per pound boiler water boiling water reactor base-exchange water softener cellulose acetate Canadian deuterium reactor continuous deionization critical heat flux Code of Federal Regulations cyclohexylamine critical heat-flux carbohydrazide cast iron boiler clean-in-place carboxymethylcellulose (sodium) carboxy-methylcellulose critical miscelle concentration cycle of concentration... 

The used raw materials were TiCU, oxygen, Ar and NaOH. The reaction apparatus consisted of gas purifiers, reactant preheaters, reactor, water cooler, separator and an off-gas treatment unit. The reactor was a 27 mm in ID. (32 mm in O.D.), 1430 mm in length quartz tube that was heated by a horizontal electrical furnace. A quartz rod and a ceramic rod, 6 mm... 

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