Plant catalyst reduction

An example of immersion stabilization is nickel catalysts for the hydrogenation of edible oils. ° The nickel catalyst is a powder that is used in batch slurry reactors. Since nickel is pyrophoric, the material must be stabilized for shipment to end user plants. After reduction in a fluid bed furnace, the catalyst is dropped under a N2 atmosphere into melted, fully hydrogenated edible oil. The thick slurry is then pastillated into droplets and solidified at room temperature. The result is small droplet-shaped solids of reduced nickel catalyst embedded in hardened edible oil. When used at the edible oil facility, the fully hydrogenated oil readily... 

As can be seen, the higher the feed pressure the lower the VI, owing to the positive effect that it has on CO conversion in an MR. MR reaction volume is three quarters of that of TR at 600 kPa and goes down to one quarter at 1500 kPa, when an equimolecular mixture is fed and a final conversion of 80% is considered. VI further decreases when a stream coming out from a reformer is fed (50% H2, 10% CO2, 20% CO, 20% H2O) into the Pd-Ag MR, owing to the low value of the equilibrium conversion (35%) (Figure 12.10). As a consequence, the amount of catalyst necessary to reach a suitable conversion is drastically reduced with clear gain also in terms of plant size reduction. 

Figure 5—9 illustrates one method to mitigate this problem. Baskets, partially filled with catalyst support balls, are inserted in the Claus plant catalyst bed. The depths of the baskets are sufficient to double the exposed surface area at the lop of the bed. While the effect on the initial reactor pressure drop is small, during the course of a one-year run, the average reduction in pressure drop was estimated to be 30%. The baskets shown in Figure 5-9 were only installed in the first reactor, as encrustation at the top of the second and third reactors is less of a problem. 

Reduction process is a key step to obtain the active phase of fused iron catalyst. Reduction process directly relates to the apphcation and the economic benefit of plant in the next few years or even longer than a decade, and that is why some plants work well while the other are not so ideal although with the same catalyst. 

It is known from Table 9.25 that for the plant whose service time of the catalyst is 7.5 years, although the catalyst should be replaced once (but the replacement can be arranged during temporary stoppages at the plant, which does not occupy the production time), the cost of catalyst increases by one time, and part output will be lost during the catalyst reduction. However, in the view of running period of 15 years, potential profit increment of the enterprise with the service time of... 

The industrial catalyst is prepared by fusion. The catalyst may be supplied in the unreduced state after crushing and screening to the desired particle size or the catalyst may be reduced and subsequently stabilized by controlled oxidation in the catalyst factory. Although the reduced catalyst is pyrophoric, the prereduced catalyst can be safely handled. In the ammonia synthesis plant the catalyst is activated by reduction with a mixture of hydrogen and nitrogen as the final step in the start-up procedure for the plant. The reduction of the prereduced catalyst is faster and simpler than the start-up of the unreduced catalyst. 

It may therefore be necessary to replace catalysts mar r times during the life of plant equipment. Stabihty despite the presence of poisons becomes an important feature of the selection procedure to avoid unscheduled plant closures. Proper catalyst reduction may also be a critical step prior to operation to ensure optimmn performance in the shortest possible time. This is not always easy and efforts have therefore been made to use prereduced catalysts and even to regenerate spent catalysts externally to restore as much of the original activity as possible. It should never be assumed that catalyst operation is straightforward. It... 

C. It occurs in natural gas. May prepared by reduction of ethene or ethyne by hydrogen under pressure in the presence of a nickel catalyst, or by the electrolysis of a solution of potassium elhanoate. It has the general properties of the paraffins. Used in low-temperature refrigeration plant. 

The semiregenerative procedure for catalyst regeneration varies slightly between catalyst vendors however, it typically follows these general steps plant shutdown, carbon bum, oxidation and chlorination, nitrogen purge, reduction, and plant start-up. During the plant shutdown, Hquid hydrocarbons... 

Design considerations and costs of the catalyst, hardware, and a fume control system are direcdy proportional to the oven exhaust volume. The size of the catalyst bed often ranges from 1.0 m at 0°C and 101 kPa per 1000 m /min of exhaust, to 2 m for 1000 m /min of exhaust. Catalyst performance at a number of can plant installations has been enhanced by proper maintenance. Annual analytical measurements show reduction of solvent hydrocarbons to be in excess of 90% for 3—6 years, the equivalent of 12,000 to 30,000 operating hours. When propane was the only available fuel, the catalyst cost was recovered by fuel savings (vs thermal incineration prior to the catalyst retrofit) in two to three months. In numerous cases the fuel savings paid for the catalyst in 6 to 12 months. 

The ionic liquid process has a number of advantages over traditional cationic polymerization processes such as the Cosden process, which employs a liquid-phase aluminium(III) chloride catalyst to polymerize butene feedstocks [30]. The separation and removal of the product from the ionic liquid phase as the reaction proceeds allows the polymer to be obtained simply and in a highly pure state. Indeed, the polymer contains so little of the ionic liquid that an aqueous wash step can be dispensed with. This separation also means that further reaction (e.g., isomerization) of the polymer s unsaturated ot-terminus is minimized. In addition to the ease of isolation of the desired product, the ionic liquid is not destroyed by any aqueous washing procedure and so can be reused in subsequent polymerization reactions, resulting in a reduction of operating costs. The ionic liquid technology does not require massive capital investment and is reported to be easily retrofitted to existing Cosden process plants. 

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