Overall operational yield

Material yield (which is more precisely called the overall operational yield ) is the maxiisum molar amount of desired product obtained from 1 mole of reactant, taking the reaction stoichioii ry into account ... 

Process development on fluidized-bed pyrolysis was also carried out by the ConsoHdation Coal Co., culminating in operation of a 32 t/d pilot plant (35). The CONSOL pyrolysis process incorporated a novel stirred carbonizer as the pyrolysis reactor, which made operation of the system feasible even using strongly agglomerating eastern U.S. biturninous coals. This allowed the process to bypass the normal pre-oxidation step that is often used with caking coals, and resulted in a nearly 50% increase in tar yield. Use of a sweep gas to rapidly remove volatiles from the pyrolysis reactor gave overall tar yields of nearly 25% for a coal that had Eischer assay tar yields of only 15%. 

Treatment of pulp with pectolytic enzymes has two additional benefits. Free-run juice is released more readily from the pulp and overall juice yield is increased. Studies with heated Concord pulp containing cellulose fibers have shown that from 1000-gram portions of pulp, free-run juice obtained 5 min after placing the pulp on an 8-mesh screen was increased from 337 ml for controls with no enzyme to an average of 387 ml for lots containing pectolytic enzymes (at a concentration equivalent to that used in commercial operations). This represented an increase of 15% in free-run juice. Total yield, combining both free-run and hand-pressed juice, increased by 3%. (Equivalent yield on a commercial basis would have been 193.6 gal/ton.)... 

Fig. 1.7. A process for styrene from ethylbenzene using IS moles steam 1 mole ethylbenzene. Operating pressure 1 bar. Conversion per pass 0.40. Overall relative yield 0.90...

The overall purification yield of recombinant enzyme is affected by the scale-up and may vary from plant to plant. The profitability at lower yields and at a constant selling price was also determined. A 10% reduction in yield resulted in a 12.9% decrease in the ROI. Conversely, the effect of increasing the plant capacity between 4545 (base case) and 45,450 kg of corn per batch on rGUS production, capital investment, UPC and ROI was estimated. A five-fold increase in capacity resulted in a reduction of 30% in the UPC, and an increase in the ROI from 52 to 91%. Further increase in the capacity did not have a significant effect on the UPC and ROI. With a five-fold increase in the capacity the total capital investment increased by a factor of 3.3, labor, administrative, and overhead expenses doubled, and the rest of the operating costs increased proportionally with the capacity. 

The typical operating conditions of xylene and EB isomerization processes are shown in Table 9.3. These conditions minimize the above side reactions. Pressure, temperature and H2/HC ratio are key parameters that define the partial pressure of C8 naphthenes intermediates for EB isomerization. Naphthene cracking and disproportionation/transalkylation are responsible for the C8 aromatics net losses that affect the overall pX yield. The C8 recycled stream from the isomerization unit to the separation unit is three times higher than the fresh feed stream (since there cannot be more than 24% of pX in the C8 aromatic cut after isomerization). This means that each percent of loss in the isomerization unit will decrease the pX yield by 3%. For example, when standard mordenite-based catalysts lead to 4% of net losses, the overall pX yield is roughly 88%. 

The overall xylene yield of the operation is estimated at over 98 per cent with an approach to the equilibrium content for p-xyleoe of 95 to 98 per cent... 

Marin et al. (250) attempted to model a reactor similar to that used by Alonso and co workers. Their simulations were compared with simulations representing a fixed-bed reactor operated under similar conditions. They concluded that the membrane reactor (with the external fluidized bed) was a viable technology for n-butane oxidation, but that it offered only a modest increase in MA yields relative to those realized in a fixed-bed reactor. Nonetheless, the safer operating conditions which keep the O2 and hydrocarbon flows separate, particularly with the oxidation of butane to MA, are desirable. Presently, MA yields are chiefly governed by the explosive limits of butane in air (i.e., 1.8%). Increasing the butane concentration with an optimized membrane reactor may increase overall MA yields. 

The optimisation of the bio-oil was aimed at adjusting the operating conditions of the fast pyrolysis process to maximize the concentration of these reactive groups in the bio-oil, while maintaining a high overall oil yield. Figure 1 shows the main part of the small-scale production facility for small amounts of the oil. It consists of the biomass feeder, the reactor and a bio-oil collection system. Before each experiment, a batch of sand was preheated inside an electrical furnace to about bOO°C, where after it is mixed with cold sawdust in the bottom of the cone. The produced vapours could be immediately removed from the hot reactor, and collected in several water-cooled vessels. 

Rh was loaded by impregnation. Addition of a small amount of 02 in the autothermal reforming reaction increases the overall H2 yield, decreases the operating temperature, and reduces the coke and CH4 formation. Detailed studies on the effect of H20/Et0H and 02/Et0H on the catalytic performance were evaluated. 

Recent advances in fixed-bed-based MAN processes include the development of reactors that can operate in the fiammable regime and of the total butane recycle processes that can give overall process yields between 65% and 75%. The ability to safely use butane feed compositions that are above the lower flammability limit of approximately 1.8% in air can translate into increased production rate of MAN, which has obvious advantages from a process economics perspective. 

It is generally accepted that the translation of solution-phase reactions to solid-phase procedures for the production of compound libraries is usually time-consuming and not always successful. The most robust solid-phase synthesis instrumentation has operational temperature and solvent compatibility limitations that impinge on the direct translation of solution-phase chemistries to the solid phase. These instrument restrictions necessitate a considerable investment in experimentation to rcdclinc the solution-phase reaction protocol for the solid phase. In spite of this apparent obstacle, a substantial number of reactions for solid-phase library production has been pubhshed. Many of these reachons cannot be exploited because the overall product yields are too low (which could lead to ambiguity in the interpretahon of the eventual assay results). Also, some reachons have a restricted range of potential monomers that lead to a hmited diversity of the compounds in the resulting library. 

The presence of cyanohydrin, which is liable to decompose into HCN and carbonylated compounds, and to lower the purity of the final product, makes it necessary to operate in the presence of a stabilizer (oxalic add), in addition to a polymerization inhibitor added at various stages of the treatment scheme for ammoxidation effluents. Acrylonitrile to specifications is obtained in a side stream. Residual hydrogen cyanide is separated at the top and recycled to the previous column. The polymers withdrawn at the bottom are stripped to recover the acrylonitrile they contam and thus to improve the overall conversion yield. 

Extraction in aqueous two-phase systems is said to be an operation that is easy to scale up (33). This is also true for affinity partitioning and is clearly illustrated by the process for purification of formate dehydrogenase (34, 35). In this study, small scale experiments gave an overall enzyme yield of 74%. When scaled up by a factor of 40 000, the yield was 70%, thus demonstrating the feasibility of evaluating the performance of extraction process on a small scale. 

The relative importance of each operator in the crystal structure can be determined by summing all the E JYs for molecules generated by that operator, yielding the overall percentage of the packing energy due to it. 

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