Overflow Oxidation process

In the first step cumene is oxidized to cumene hydroperoxide with atmospheric air or air enriched with oxygen ia one or a series of oxidizers. The temperature is generally between 80 and 130°C and pressure and promoters, such as sodium hydroxide, may be used (17). A typical process iavolves the use of three or four oxidation reactors ia series. Feed to the first reactor is fresh cumene and cumene recycled from the concentrator and other reactors. Each reactor is partitioned. At the bottom there may be a layer of fresh 2—3% sodium hydroxide if a promoter (stabilizer) is used. Cumene enters the side of the reactor, overflows the partition to the other side, and then goes on to the next reactor. The air (oxygen) is bubbled ia at the bottom and leaves at the top of each reactor. 

Sulfur Dioxide Reductant. The Mathieson process uses sulfur dioxide, sodium chlorate, and sulfuric acid to produce chlorine dioxide gas with a much lower chlorine content. The sulfur dioxide gas reductant is oxidized to make sulfuric acid, reducing the overall acid requirement of the process. Air is used to dilute the chlorine dioxide produced by this process. The exit gases flow through a scmbber to which chlorate is added in order to remove any unreacted sulfur dioxide. Spent Hquor, containing some unreacted chlorate, sulfuric acid, and sodium sulfate, continuously overflows from this process. 

To maximize the current limit that could be shunted by redox additives so that the occurrence of such irreversible processes due to overflowing current could be more efficiently suppressed, the redox additive apparently should be present in the electrolyte at high concentrations, and both its oxidized and reduced forms should be very mobile species. Where the criteria for selecting potential redox additives are concerned, these requirements can be translated into higher solubility in nonaqueous media and lower molecular weight. In addition to solubility and diffusion coefficients, the following requirements should also be met by the potential redox additives (1) the formal potential of the redox couple [R]/[0] should be lower than the onset potential for major decom-... 

A recent processing development has been the continuous oxidizer, shown in Figure 3 (91). The charge is fed to the bottom of the column, where air is also introduced. At the top of the column the liquid overflows into a buffer tank. From this the oxidized asphalt is drawn off by means of a pump, provision being made for recirculation. 

Industrially, a continuously operating overflow tank is generally used. About twice the stoichiometric quantity of water is added to the calcium oxide in a premixer and the mixture transported to the reaction tank, in which the heat from the exothermic reaction heats up the reaction mixture to 100° C. The evaporating excess water entrains the very small lime hydrate particles and carries them upwards, where they are separated by an overflow from the coarse particles. The hydration process is then completed. The calcium hydroxide obtained contains less than 1 % water. 

Increased moistening of the feed mixture was found to increase the particle size of the overflow calcine as long as the moisture content of the feed was lower than 11 % H2O. The larger partieles drop to the bed and the oxidation reactions increase both the bed temperature and furnace heat production. Simultaneously, the furnace control system decreases the feed rate in order to keep the bed temperature constant. Figure 15. The feed rate may be increased with more effective cooling of the furnace if the sulfide level is not too high. The process gas temperature in the top of the furnace deereases because fewer fine particles bum above the bed, while simultaneously dust carry-over decreases, Figures 16. 

N Reactor fuel elements were discharged to the spent fuel basin via a large tunnel-like canal located at the outlet face of the N Reactor. During this transfer process, a large quantity of reactor primary-cooling-circuit water, containing considerable amounts of suspended and soluble metals and metal oxides was added to the spent fuel storage basin. Excess basin water was routed to the 116-N-l and/or 116-N-3 cribs via the basin overflow weirs and a... 

The process is carried out in a simple, vertical bubble contactor as shown in Figure 16-7. The contactor is equipped with inlet and outlet gas nozzles,. slurry feed and overflow nozzles, a drain, a manway, a mist eliminator, and a gas distributor. Gas bubbles rise from the distributor and provide the agitation to keep the zinc oxide particles in suspension. 

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