Batch Versus Continuous Operation

Back-mix reactor design, 721, 728 Baffles in heat exchangers, 595, 610-612 pressure drop over, 599-602, 605-606 Bailee s liahihty, 263 Balance sheet, 140-142 Barometric-leg pumps, 523 Batch operation versus continuous, 35-36 Batch-reactor design, 721-727 Battery-limit additions, definition of, 167 Berl saddles, 688-690 cost of 710... 

Oil and gas operations today are almost universally constitute a continuous run operation versus a batch process. Once fluids and gases are found and developed they are transported from one process to another without delay or interruption. This provides improved economics, but also increases the fuel inventories and thereby inherent risk in the operation. 

Given that extruders of various designs, types and geometries are available in the marketplace, let us examine some aspects that drive selection of the appropriate extruder for a product. The key factors relevant in selecting the extruders are formulation factors (selection of excipients, thermal stability, plasticity, aqueous solubility, and moisture holding capacity) and equipment factors (batch versus continuous operation and scalability of the extruder). 

CA 40, 206 (1946) (Continuous production and stabilization of NC, NS, DEGDN, PETN Nitrosugar) 21a)E.Berl, ChemMetEngrg 52, 202, 204 206(Way 1945) (The problem of batch versus continuous operation in the explosives industry is primarily concerned with improvements in safety of operations) 2lb)AA.Swanson et al, PB Rept... 

Batch versus Continuous Process in Unit Operations and Equipment... 

A second stream can also be used in RBatch by attaching it to the blue arrow on the side of the reactor called Continuous Feed (optional) (see Fig. 4.21). As the name implies, this stream is used if fed-batch operation is desired. This stream is a real flowing stream, whose flow-versus-time profile can be specified, as we will illustrate later. 

Valuable information on material and energy balances can be obtained, and process conditions can be examined to supply data on temperature and pressure variation, yields, rates, grades of raw materials and products, batch versus continuous operation, material of construction, operating characteristics, and other pertinent design variables. 

Mode of operation (fed)-batch versus continuous Parameters for decision kinetics, stability and form of the biocatalyst desired substrate conversion, product concentration (solubility) need of process control, inhibitory/toxic effect of substrate or product. Examples for fed-batch bioprocesses acrylamide process (Nitto Chemicals), L-carnitine process (Lonza). Examples for continuous operation.- production of L-tert. leucine and other amino acids (Degussa). 

Another consideration for the scale of a process is batch versus continuous. Batch processes limit production to the size and number of batches that can be produced in a given amount of time. Continuous production allows for uninterrupted operation, with the production rate controlled by the throughput of the equipment. The atomization and coextrusion technologies are the most common continuous encapsulation processes. Spray-coating processes are available as both batch and continuous. The emulsion-based processes are limited to batch processing, which is the basis for their increased operating costs over most of the physical processes. 

Della Porta, G., Campardelli, R., Falco, N., and Reverchon, E. PLGA microdevices for retinoids sustained release produced by supercritical emulsion extraction Continuous versus batch operation layouts. Journal of Pharmaceutical Sciences 100 (2011) 4357-4367. 

The first step in the economic design hierarchy of Douglas is the choice of batch versus continuous operation. With a production rate of 365,000 tons of chlorine per year, this... 

The extent to which any of these transformations occurs is linked to the final product being made, the type of mixer, it s mode of operation (e.g., batch versus continuous) and it s operating conditions (including mixing time). 

Continuous Process Operation versus Batch-Type Process.409... 

In the manufacture of a chemical product that is actually a chemical, batch operations are often employed. This is because specialty chemical products are usually produced in small batches. In the Douglas hierarchy discussed in Chapter 2, the first decision to be made in designing a chemical process is batch versus continuous. For production of a commodity chemical in the quantities reflected in the exartples on the CD-ROM accompanying this book, the choice will always be a continuous process. Similarly, for production of a specialty chemical, the choice will almost always be a batch process. 

Continuous mixing is the preferred option for processes where throughput is high, space is a constraint, storage of intermediates must be avoided, or the material has a tendency to segregate. A continuous mixer can be a low-cost and rehable option if the operating variables are appropriately controlled. Selection of batch versus continuous mixing has been discussed in Section 15-9. 

Many mixers can be operated in either batch or continuous mode. It is advised that the selection of batch versus continuous operation be made before any tests are conducted. The mixing tests should be conducted in appropriate mode. For instance, performance of a paddle mixer in continuous mode of operation cannot be reliably estimated from batch experiments. 

Figure 17.9. Dialyzed Chemostat Estimated values of specific MAb production rate versus time during the initial batch start-up and subsequent dialyzed continuous operation with a dialysis flow rate of 5 IJd.

Figure 4.29 shows the Operating Times page tab. The Batch feed time bullet is clicked and specified to be 1 h. This means that the 50 kmol/h specified for the FE feedstream is on an hourly basis. To help clarify this none-too-intuitive aspect of the feedstream, if a value of 2 h is specified for the Batch feed time, the flowrate of the FE stream will be set at 50 kmol/2 h. Several other straightforward parameters are also set on this page tab. Figure 4.30 shows the Continuous Feeds page tab, on which a fiow-versus-time profile can be specified. 

Even in this specific area, there are still a number of possible methods for classifying crystallizers. Operating classifications such as continuous versus batch and agitated versus unagitated are obvious but much too general. 

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