Molten operating conditions

Oxidation Step. A review of mechanistic studies of partial oxidation of propylene has appeared (58). The oxidation process flow sheet (Fig. 2) shows equipment and typical operating conditions. The reactors are of the fixed-bed shell-and-tube type (about 3—5 mlong and 2.5 cm in diameter) with a molten salt coolant on the shell side. The tubes are packed with catalyst, a small amount of inert material at the top serving as a preheater section for the feed gases. Vaporized propylene is mixed with steam and ak and fed to the first-stage reactor. The feed composition is typically 5—7% propylene, 10—30%... 

As demonstrated by the recent works on corrosion, it is worthwhile to have at our disposal (or to acquire) a perfect knowledge of the whole environmental conditions i.e. of the considered molten salt chemistry and its dependence on the nature of the cover gas. This allows us to predict, from a thermodynamic point of view, the operating conditions leading to reduced corrosion effects, the consistency of which is being further experimentally tested. 

Copper chloride is universally applied as catalyst. - Known as the modified Deacon catalyst, CuCl2 is supported on alumina and contains KC1. Under operating conditions a CUCI2-CU2CI2-KCI ternary mixture, possibly in the molten state, is... 

Wetzel (75) atomized both molten wax and a molten alloy in a Venturi nozzle and established empirical equations for expressing the magnitudes of the effects of operating conditions on the particle-size distribution of the spray. An advantage of molten alloy is that a permanent record of the spray is obtained and large numbers of particles may be sized by physical methods. 

Vanadium pentoxide, V205, is used as a catalyst in the oxidation of sulfur dioxide. The mechanism involves oxidation-reduction of V205 that exists on the support at operating conditions in the molten state. The mechanism of reaction is ... 

The mixed gas, composed of hydrogen chloride and hydrocarbons, which are separated in the molten polymer vessel, goes into dehydrogen chloride gas incinerator and the hydrocarbons are burnt ont at 1300°C. The incinerator and the operating conditions are designed and operated to prevent the generation of dioxin. The hydrocarbon-free exhanst gas from the incinerator is quenched and absorbed into water in the HCl absorber to give 20 wt% hydrochloric acid. 

Yoshioka, S. Urushibata, H. Superiority of Li2C03/Na2C03 electrolyte in molten carbonate fuel cells. I. Influence of operation conditions on polarization behavior. Denki Kagaku 1996, 64 (8), 909-914. 

The five main steps identified by ANL in the hybrid Cu-Cl Cycle are shown in Table 1 with details pertaining to the operating conditions. Basically, the cycle is mainly a closed one, as shown pictorially in Figure 1, except for feed water, heat and electricity requirements. In Step 1, solid Cu is reacted with HCl gas to produce H2 gas and Cu-Cl in a molten state. Step 2 uses the Cu-Cl from Steps 1 and 5 to produce the Cu required for Step 1 through an electrochemical process. The reaction between solid CUCI2 and steam (Step 4) produces the HCl gas required in Step 1. In Step 5, the CuO" CuCl complex formed in Step 4 is decomposed to produce O2 gas as output and CuCl for Step 1. Hence, all chemicals are recycled with only H2 and O2 as products from the process. 

Example 2.5 Wafers for integrated circuits are made of pure silicon that is produced by reacting raw silicon with HCl to form silicon trichloride, SiHCls. The silicon trichloride is reduced later with hydrogen to provide pure silicon. At the reactor operating conditions, silicon tetrachloride, SiCl4, is also formed. Molten raw silicon is fed into a flow reactor at a rate of 80 Ibmol/h, and gaseous HCl is fed in proportion of 4 mol HCl per mole silicon. The reactor operates at 1250°C and the following reactions take place ... 

The presence of sodium and vanadium complexes in the fuel oil ash can, under certain plant operating conditions, result in considerable harm to the equipment. Spalling and fluxing of refractory linings is associated with the presence of sodium in the fuel. Above a certain threshold temperature, which will vary from fuel to fuel, the oil ash will adhere to boiler superheater tubes and gas turbine blades, thus reducing the thermal efficiency of the plant. At higher temperatures, molten complexes of vanadium, sodium, and sulfur are produced that will corrode all currently available metals used in the construction of these parts of the plant. TTie presence of trace amounts (ASTM D-1318) of vanadium (ASTM D-1548, IP 285, IP 286) in fuel oil used in glass manufacture can affect the indicator of the finished product. 

In normal operation, the butane feed is practically not oxidized, but is burned with the residual gases to produce steam. The operating conditions are closely similar to those used for the oxidation of benzene. BASF (Badische Amlin und Soda Fabrik) uses a fixed bed multi-tube reactor cooled by external molten salt circulation, operating between 360 and 440°C, also producing high-pressure steam. The maleic anhydride selectivity in relation to oxidizable butenes is about 50 molar per cent. 

Based on this engineering study we concluded that further laboratory studies should be made more fully to define the primary reactor catalyst loadings required to approach equilibrium conversion of sulfur dioxide to sulfur vapor over the range of pilot plant operating conditions. The reactor used in this additional study duplicated as nearly as possible the geometry of the proposed pilot plant reactor. The laboratory reactor was fabricated of type 304 stainless steel pipe. An electrically heated molten lead bath maintained the desired operating temperature. 

The oxidation of SOi to sulfuric acid, SOt + H2O + 0.5 O2 H2SO4, is catalyzed by potassium vanadium(V) oxide compounds. A typical catalyst preparation sequence involves impregnation of a silica support with a solution containing potassium vanadate (K/V = 3), followed by drying and subsequent calcination at 500°C in air. Under typical operating conditions in SO2/O2/SO3 atmospheres at 400-500°C, the catalytically active species is molten and forms a thin liquid film on the silica. support. As such the. system functions like a bulk oxide catalyst under operating conditions, and the silica mostly serves as a mechanical support medium. 

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