Batch operation filling

Figure 7. Effect of methane conversion on C2 selectivity for some of the best state-of-the-art OCM catalysts (A, based on ref 4), the simulated chromatographic reactor of Aris and coworkers (A, ref. 10) and the present work. ( ) Ag electrocatalyst, single pass (O) Ag electrocatalyst with recycle and trapping (0) Sr/LagOg catalyst, single pass ( ) Sr/La20g catalyst with recycle and trapping. Open symbols, batch operation filled symbols, continuous-flow steady-state operation.

These devices are replacing the older tank and spiral-conveyor devices. Better provisions for speed and ease of fill and discharge (without powered rotation) minimize downtime to make this batch-operated device attractive. Heat-transfer coefficients ranging from 28 to 200 W/(m °C) [5 to 35 Btu/(h fF °F)] are obtained. However, if caking on the heat-transfer walls is serious, then values may drop to 5.5 or 11 W/(m °C) [1 or 2 Btu/(h fH °F)], constituting a misapplication. The double cone is available in a fairly wide range of sizes and construction materials. The users are the fine-chemical, pharmaceutical, and biological-preparation industries. 

Often pilot plant or research data for developing a process are obtained on a batch operation. Later, a continuous process will usually prove that smaller equipment can be used and that the operation. vill be more economical. Normally batch mixing requires 10%-25% more power than continuous [29] for stable conditions how ev-er, the reaction time for continuous flow is always longer than the reaction time for batch flow, but the practical result may show batch time cycle is increased by filling,... 

Batch Reactor. Let the batch reactor be filled with a macrofluid containing reactant A. Since each aggregate or packet of macrofluid acts as its own little batch reactor, conversion is the same in all aggregates and is in fact identical to what would be obtained with a microfluid. Thus for batch operations the degree of segregation does not affect conversion or product distribution. 

In semi-batch operation, the SCISR is first filled with a solution of sodium silicate with certain concentration, and then a sulfuric acid solution of a given concentration is dripped at a certain rate into the reactor to react with the sodium silicate at a controlled temperature. The reaction continues for a certain interval of time after the dripping has finished. Stirring is then stopped for ageing of the precipitate for a term, and then the precipitate is sampled and the sample is measured with a laser particle-measuring instrument of FAM type to obtain the sizes and size distribution of the particles in the wet product. 

The reactor is characterized by no addition of reactant or removal of product during the reaction. Any reaction being carried out with this constraint, regardless of any other reactor characteristic, is considered batch. The assumptions for batch operation are (1) the contents of the tank are well mixed, (2) reaction does not occur to any appreciable degree until filling and startup procedures are complete, and (3) the reaction stops when quenched or emptied. The reactor can be operated with either a homogeneous or heterogeneous reaction mixture for almost any type of reaction. 

The low volumetric productivities that characterize batch cultivation processes are a disadvantage for the use of this operation mode for production. However, a variant known as repeated batches is an interesting alternative. It consists of initially carrying out a batch cultivation for the time needed to attain the desired product concentration. At that moment, just a part of the bioreactor contents is harvested. The remaining cell suspension inside the bioreactor is then used as inoculum for a new batch, by filling the vessel with fresh medium. This procedure can be repeated several times, until a decrease in cell growth or product formation is observed. The use of repeated batches allows a decrease of the time the bioreactor is non-productive. This eliminates the time periods that would be necessary for cleaning and sterilization between each batch. 

High labor and handling costs as well as the start-up and shutdown times required to fill and empty the reactor are important drawbacks in a batch operation. Continuous flow systems are nearly always more cost-effective than batch reactors, especially when large volumes are to be treated, i.e., the main application of this reactor configuration is wastewater treatment. The removal of phenolic compounds from waters has been performed using SBP and HRP in continuous stirred tank reactor (CSTR) [49, 75, 76, 81, 83, 84],... 

Fig. 33 Effect of monomer concentration Mpi fed to the first tubular seeding reactor with back mixing on the number of polymer particles produced (Sq (NaLS)=6.25 g/dm -water, Iq (KPS)=1.25 g/dm -water, Mpi (St)=variable 50 °C. Experimental data empty circles, particle number observed at t=40 min in a batch reactor filled circles, steady-state particle number observed in the first tubular seeding reactor operated with mean residence time r=40 min)...

The total cycle time in any batch operation is considerably longer than the reaction time, as one must account for the time necessary to fill (t ) and empty (f,) the reactor together with the time necessaty to clean the reactor between batches, In some cases the reaction time calculated from Equation (4-5) may be only a small fraction of the total cycle time, t,. 

In industry, the LFCB is used to conduct small batch sterile filling operations, in the general manipulation and isolation of non-hazardous materials, and in quality assurance/quality control (QA/QC) sterility testing. 

In industry, the BSC is used to conduct small batch sterile-fill operations, manipulation (weighing and pouring), isolation of hazardous materials, and in QA/QC testing applications. All classes of BSC are encountered in pharmaceutical manufacturing operations for a wide variety of processing applications. 

Table 1 shows that the maximum ethanol concentration in this test was 67.7 g/1, in the outlet of the third reactor, for a flow rate of 8.1 ml/h. In this condition, the TRS and glucose concentrations were 3.3 and 0.8 g/1, respectively. The system is stable for all flow rates. The lowest flow rate, 8.1 ml/h, was more difficult to control, which was what led to some more pronounced oscillation of the variable values in this condition. It was expected in the continuous run that similar results than the ones obtained in the batch run will be achieved. As in batch operation, the cycle time is considerably longer than the reaction time, if the continuous process had reached a similar performance than the one obtained with the batch run in the continuous operation, we could save cycle time (times to clean, to fill ant to empty the reactor). Therefore, from the industrial point of view, the continuous process would lead to higher productivities. 

A 20 semi-batch reactor is imtlaliy charged with solvent and initiator to half its total volume. A pure monomer feed is wly added at flowrate Q/o = 1 m /min to. fill, the reactor in semi-batch operation to control the heat release. 

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