Secondary reactor

The desired form in homopolymers is the isotactic arrangement (at least 93% is required to give the desired properties). Copolymers have a random arrangement. In block copolymers a secondary reactor is used where active polymer chains can further polymerize to produce segments that use ethylene monomer. 

In addition to secondarv resistance control, other devices such as reactors and thyristors (solid-state controllable rectifiers) are used to control wound-rotor motors. Fixed secondary reactors combined with resistors can provide veiy constant accelerating torque with a minimum number of accelerating steps. The change in slip frequency with speed continually changes the effective reac tance and hence the value of resistance associated with the reactor. The secondaiy reactors, resistors, and contacts can be varied in design to provide the proper accelerating speed-torque curve for the protection of belt conveyors and similar loads. 

Naphtha transfer line Recycle gas transfer line Reheat outlet Primary reactor Secondary reactor Pressure, lb./sq. inch gage Feed rate, bbl./day Space velocity, vol./hour/vol. 

The typical process for producing a 42% high-fructose syrup is shown in Figure 21.8.32 A starch solution at about 35% solids and a pH of about 6.5 is drawn into a steam jet at 180°F (82°C) in the presence of a calcium-stabilized, thermostable alpha-amylase. The slurry is maintained at this temperature through a series of loops for 3-5 minutes and then cooled to 95°C (200°F) in a secondary reactor, where further alpha-amylase additions occur. A holding time of up to 120 minutes in the secondary reactor produces a solution of approximately 12 DE. The pH is adjusted to about 4.3... 

Using the data in Problem 9.29, calculate the effluent BOD5 from the secondary reactor if the influent BOD5 is 150 mg/L. 

Three very different types of catalyst are being used in the secondary reactor for upgrading the gas from the gasifier exit ... 

Equilibrium H2 and CO compositions can also be derived thermodynamically. Depending on the ultimate application for the gas product, H2/CO ratio can be further tailored by integrating with secondary reactor stage (e.g., WGS) or by optimizing catalysts or operating conditions. 

The alternative process uses air instead of oxygen. The operation of this system is totally different since now a large amount of inert nitrogen would end up in the recycle. Therefore a large amount of the gas is vented, which simultaneously circumvents the removal of carbon dioxide. The conversion per pass, however, must be much higher, and the amount of ethene in the off-gas is still too high for direct venting into the atmosphere and hence a secondary reactor is needed. 

The original vapor phase design accomplished the alkylation and transalkylation reactions in a single reactor. Subsequent designs performed the transalkylation reactions in a vapor phase, secondary reactor that was separate from the alkylation reactor. Fig. 3 shows a flow diagram for the latest publicly disclosed version of the process, sometimes referred to as the third-generation EB process. The alkylation and... 

The high activity of a ruthenium-promoted iridium catalyst has improved productivity in plants that previously used rhodium catalysts [123], For example, a 75% increase in throughput was achieved at the Samsung-BP plant in Ulsan, South Korea. Another benefit of the iridium catalyst is higher selectivity, with smaller amounts of both gaseous and liquid by-products. The WGS reaction does occur, but at a lower rate than for rhodium, resulting in reduced formation of C02 and CH4. Since the process is less sensitive to CO partial pressure, the reactor can operate with a lower rate of bleed of recycle gas which, in combination with the secondary reactor, results in an increase in CO conversion from 85% (Rh) to >94% (Ir). Selectivity to acetic acid is >99% based on methanol with reduced propionic acid by-product formation relative to the process with the rhodium catalyst. This, along with the lower water... 

This can be carried out in several (4) agitated reactors in series or in a column with several injection levels. In the former case, hydroxylamine sulfate reacts with an approximately equal-weight mixture of cyclohexanone and oxime in the primary reactor. The sulfuric acid is then neutralized by ammonia. The liquid oxime rises above the solution of ammonium sulfate and hydroxylamine sulfate. In the secondary reactor, this solution reacts with the fresh cyclohexanone feed. This is followed by a second neutralization by ammonia, in order to obtain the initial effluent (50 50) of cyclohexanone and oxime fed to the primary reactor. 

From the data of Tables II and III, it may be calculated that equilibrium conversion of hydrogen sulfide and sulfur dioxide to sulfur vapor in the secondary reactor is 78.0%. Cooling this gas stream to 140 °C (413 K) will lead to a liquid sulfur recovery of 76.1% of the secondary reactor output. Overall recovery in the two stages, then, may be calculated to be 94.9%. 

Ethylbenzene is used mainly for the manufacture of styrene. Among impurities, diethylbenzene is very important, because dehydrogenation to divynilbenzene, which is harmful in polymerisation. It is worth to keep in mind that the formation of troublesome impurities should be prevented by the design of the reaction system. In this respect the catalyst plays a determinant role. Zeolite-type catalysts should give less polyalkylbenzene. The use of an excess of reactant can help to shift the product distribution to higher yield in ethylbenzene. Another possibility is to use a separate reactor for transalkylation. The trade-off between of a larger recycle of benzene and the use of a secondary reactor is a matter of optimisation. 

In many practical cases, a two stage operation is attractive, where the majority of metal-ion is removed from solution (as metal) in a primary reactor, leaving the secondary reactor to polish the residual solution. Two variants of this approach are shown in figure 6. It is also possible for one of the stages (particularly the polishing one) to be non electrochemical i.e. chemical or physical techniques for metal-ion separation may be used in concert with an electrochemical one[4, 18, 19,]. 

General improvements of oxidation reactors (e.g., for terephthalic acid) include optimized feed points for gas and liquid, internals such as spargers, mixers, draft tubes, or trays, or an optimized setup with a secondary reactor [50, 51]. 

It is sometimes convenient to use a secondary reactor instead of a recycle to the first primary) reactor. In such a case, while the input ratio (this... 

The choice between recycle to a single (primary) reactor and a secondary reactor is often dictated by cost considerations. 

In another study, an apparams consisting of a primary pyrolyzer (Pyroprobe 1000) combined with a secondary reactor was used to study the thermal decomposition of three different chemical sewage sludges. The pyrolysis gases were swept directly into a gas chromatograph for analysis. Yields of 12 pyrolysis products were determined (methane, ethylene, ethane, propylene, propane, methanol, acetic acid, acetaldehyde, C4-hydrocarbons, CO, CO2, and water). The temperatures could be adjusted in the two-stage process such that nearly all of the organic material was converted to CO, CO2, and water at temperatures that retained the heavy metals (except for Cd and Hg) in the final residue. 

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