Conversion single pass

Single-pass conversions of acetone cyanohydrin are 90—95% depending on the residence times and temperatures in the generator and hold tank. Overall yields of product from acetone and hydrogen cyanide can be >97%. There are no significant by-products of the reaction other than the sodium salts produced by neutralization of the catalyst. 

Figure 2a Maximum single pass conversion and initial rate in the absence of TCE for each compound vs. dark adsorption. (+ conversion, o, rates filled circles indicate compoimds for which conversion is less than 95%).

RO systems today accomplish the conversion either with a single or a double pass. From the Information provided to me by permeator and system manufacturers, and from discussions with individuals active in the Industry, it appears that about 60% of seawater systems use single pass conversion. One must add here that there are also differences in the configuration of RO membranes within the permeators. While there are others, the spiral wound and the hollow fiber designs truly command the market place today. Again, estimating, it appears that the hollow fiber design also has about 60% of the market. 

The fixed bed system, which offers the same advantage of low raw material cost, also is licensed widely despite the possible disadvantages of reactor corrosion problems, low single-pass conversion, and poor tem-... 

The reasons to perform electrochemistry, in particular, electrosynthesis, in a microfluidic system are the following (Rode et al., 2009) (1) reduction of ohmic resistance in the electrochemical cell, by decreasing the distance between anode and cathode, (2) enhancement of mass transport by increase of electrode surface to cell volume ratio, also realized by small interelectrode gaps, (3) performing flow chemistry to establish single-pass conversion, and (4) coupling of cathode and anode processes, permitting simultaneous formation of products at both electrodes. The latter... 

At low inlet conversions, the single-pass conversions are so high that not all of the water produced in one pass can be stripped. Therefore, at the initial stages of... 

To study the influence of the acid concentration, an experiment with an initial hexanoic acid concentration of 20 mol% and 11 mol% initial octanol concentration was carried out. As expected, very high octanol selectivity and octanol conversion are achieved (Fig. 8.32). However, taking the 1.8-fold higher acid concentration into account, enhancement of the single-pass conversions is lower than expected. As the... 

The results in Figure 3.3 are quite intuitive for the selected reactor size, the conversion in the reactor is low at low values of the reaction rate constant k. The reactor effluent will therefore contain a significant amount of reactant A, which must be separated and recycled, and in this case the flow rate of the material recycle stream is very high compared with the flow rate of the feed stream (Case II). Conversely, at high single-pass conversions, the required recycle flow rate drops sharply (Case I). 

Evidently, changes in the reactor size impact on the above findings allowing an increase in the reactor holdup leads to an increase in the single-pass conversion and reduces the flow rate of the material recycle stream. While plant configurations with low reactor capacity are preferred in processes featuring multiple reactions with valuable intermediate products (Luyben 1993b), the optimal sizes... 

Assumption 5.3. The process conditions and constraints (e.g., low single-pass conversion) are such that, at steady state, the flow rate of the material recycle stream, FrjS, must be kept significantly larger than the process throughput Fo>s. This is reflected in a large recycle number Rc ... 

In what follows, we consider the process of Figure 5.3, consisting of a gas-phase reactor and a condenser that are part of a recycle loop. This process is similar to the one discussed in Chapter 4 in that the feed stream contains the reactant A (of mole fraction j/a,o) as well as a small quantity yi o of an inert, volatile impurity I. However, in the present case, the slow first-order reaction A —> B results in a low single-pass conversion for the given equipment size. Consequently, the reaction mass contains an appreciable quantity of unreacted reactant A and... 

C. Benzene (C6H6) is converted to cyclohexane (C6H12) by direct reaction with H2. The fresh feed to the process is 260 L/min of C6H6 plus 950 L/min of H2 at 100°C and 150 kPa. The single pass conversion of H2 in the reactor is 48% while the overall conversion of H2 in the process is 75%. The recycle stream contains 80% H2 and the remainder benzene (no cyclohexane). 

The platinum-graphite packed-bed electrode and the iodide-mediated electrode provided currents in the region of lOOmA/cm. The single-pass conversion of SO2 to H2SO4 was about 20% using platinum deposited on graphite as the electrode. 

TEST What are the overall and single-pass conversions for the process shown in Figure 4.5-1 on... 

The process is to be designed for a 95% overall conversion of propane. The reaction products are separated into two streams the first, which contains H2, C3H6, and 0.555% of the propane that leaves the reactor, is taken off as product the second stream, which contains the balance of the unreacted propane and 5% of the propylene in the first stream, is recycled to the reactor. Calculate the composition of the product, the ratio (moles recycled)/(mole fresh feed), and the single-pass conversion. 

What is the overall conversion of A for this process What is the single-pass conversion ... 

The feed to the reactor (not the fresh feed to the process) contains 28.0 mole% CO2, 70.0 mole% H2, and 2.00 moIe% inerts. The single-pass conversion of hydrogen is 60.0%. Calculate the molar flow rates and molar compositions of the fresh feed, the total feed to the reactor, the recycle stream, and the purge stream for a methanol production rate of 155 kmol CH OH/h. 

Reactor. 4 unknowns ( 1, 21 3i 4) + 1 reaction - 4 independent balances (CO2, H2. CH3OH, H2 O) -1 single-pass conversion => 0 degrees of freedom. We will therefore be able to determine i, 2, 3, and rt4 and proceed from there. 

A single-pass conversion of 60.0% is achieved in the reactor. The methanol in the reactor product is separated from the formaldehyde and hydrogen in a multiple-unit process. The production rate of... 

The feed to the reactor (not the fresh feed to the process) contains 3 moles of ethylene per mole of oxygen. The single-pass conversion of ethylene is 20%, and for every 100 moles of ethylene consumed in the reactor, 90 moles of ethylene oxide emerges in the reactor products. A multiple-unit process is used to separate the products ethylene and oxygen are recycled to the reactor, ethylene oxide is sold as a product, and carbon dioxide and water are discarded. 

Methanol is produced by reacting carbon monoxide and hydrogen at 644 K over a Zn0-Cr203 catal t. A mixture of CO and H2 in a ratio 2 mol H2/moI CO is compressed and fed to the catalyst bed at 644 K and 34.5 MPa absolute. A single-pass conversion of 25% is obtained. The space velocity, or ratio of the volumetric flow rate of the feed gas to the volume of the catalyst bed, is (25,000 m /h)/(l m catalyst bed). The product gases are passed through a condenser, in which the methanol is liquefied. 

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