Batch unit

The intrinsic rejection and maximum obtainable water flux of different membranes can be easily evaluated in a stirred batch system. A typical batch unit (42) is shown in Figure 5. A continuous system is needed for full-scale system design and to determine the effects of hydrodynamic variables and fouling in different module configurations. A typical laboratory/pilot-scale continuous unit using computer control and on-line data acquisition is shown in Figure 6. 

A tray and compartment dryer is a batch unit that uses a stationary tray or compartment to dry the waste, generaUy before transport for disposal or further treatment. Some units can be mounted on removable tmcks. 

Process Unit or Batch Unit A process unit is a collection of processing equipment that can, at least at certain times, be operated in a manner completely independent from the remainder of the plant. A process unit normally provides a specific function in the production of a batch of product . For example, a process unit might be a reactor complete with all associated equipment (jacket, recirculation pump, reflux condenser, and so on). However, each feed preparation tank is usually a separate process unit. With this separation, preparation of the feed for the next batch can be started as soon as the feed tank is emptied for the current batch. 

If the batch units are capable of continuous subdivision, we proceed as follows. We substitute the given values of the cumulative-average cost Y and cumulative production X for the first batch into Eq. (9-63) to give, by taking logarithms of each side,... 

Many larger installations also feature a batch stiU. Material to be separated may be high in solids content, or it might contain tars or resins that would plug or foul a continuous unit. Use of a batch unit can keep solids separated and permit convenient removal at the termination of the process. 

Continuous filters are most attractive when the process apphcation is a steady-state continuous one, but the rate at which cake Forms and the magnitude of production rate are sometimes overriding factors. A rotaiy vacuum filter, for example, is a dubious choice if a 3-mm (0.12-in) cake will not form under normal vacuum in less than 5 min and if less than 1.4 mVh (50 ftVh) of wet cake is produced. Upper producdion-rate limits to the practicality of batch units are harder to... 

Sometimes a system of mixing and dispersing is composed of one or more batch units providing a feed to a continuous intensive dispersion unit. Another possibihty would be a batch mixer and surge bin which provide a continuous feed to a final dispersion unit. Various combinations of this type with adequate samphng at the proper points may be used when continuous flow would be beneficial provided that certain features could be overcome. 

This control activity includes process control and unit management. Process control includes those loops and devices that perform sequential control, regulatory control, and discrete control. Unit management is responsible for coordinating the activities associated with the batch units (e.g., allocating resources within the unit, ensuring that batch sequences proceed in the proper order, etc.). 

Dilution, separation, and neutralization can take place in the same reactor or several batch units may be used for the consecutive steps (see also Sec. XX.X). Sulfuric acid sulfonation in a continuous loop reactor system is feasible when an H2S04/AB ratio of at least 1.80 is applied. In this case, as well as when 20% oleum is used, reasonably short reaction times are sufficient to complete the reaction. With increasing H2S04/AB ratio, the amount of dark 80% sulfuric acid (spent acid) will increase proportionally. 

The batch plant shown in Fig. 7.4-6 is to be optimized. The required production capacity is 11070 m per year. The cost coefficients (see Eqn. 7.3-4) are given in Table 7.4-7. The fixed processing times in the batch units, /i. r, are given in Table 7.4-8 together with initial values of processing times in the semi-continuous units, 04-( and those found by optimization. The total batch times, volumes, and costs are also given in this table. 

The minimal cost of equipment was used as the criterion in the design of the plant, which was to be operated in a non-overlapping mode. For a plant consisting of MB true batch units (MS = 3) and MS semi-continuous units (MS = 5) which are grouped in MST semi-continuous trains (MST = 3), the cycle time is given by Eqn. (7.4-10). Combining this expression with Eqn. (7.4-22) and rearranging yields ... 

When a plant is designed, aunit may be designed with excess capacity to facilitate a future expansion. For instance, consider a batch process that has a continuous purification step, such as distillation or extraction. If it is planned to expand this plant a few years after it starts up, it might be wise to put the extra capacity in the continuous unit and to plan a layout that will easily allow the addition of other batch units. 

Continuous ion-exchange units are also available in which ion exchange and resin regeneration both occur constantly. In this case both the resin bed and the fluid being purified are in motion. Continuous units are usually more economical than batch units when the rate of ion removal exceeds 1 lb/min (0.5 kg/min).39... 

The composition of the dispersion agents, which are produced in dedicated reactors, is the same for all recipes. The batch sizes may be one or two polymerization batch units for Dl and one, two, three or four polymerization batch units for D2. The processing times are ten hours for Dl and two hours for D2, and they do not depend on the batch sizes. The dispersion agents in their final states are unstable in the reactors and stable for limited periods of time in the storage... 

Recommendation (Blue Grass) GA-2. The technology provider should consider that the ERH and PRH units for a full-scale GATS process at Blue Grass be batch units similar in design to those tested. 

Phenomena, methods of operation, etc. have been studied extensively for the use of crystallization in separation processes. Although much remains to be learned about such processes, relatively little attention has been given to the other functions and the purpose of this work was to examine the role of various process variables in determining the purity of crystals recovered from a batch crystallizer. The system studied experimentally was a model system of amino acids, and the key variables were the composition of the liquor from which a key amino acid was crystallized, the rate at which supersaturation was generated by addition of an acid solution to reduce solubility, and the degree of mixing within the batch unit. 

The development of adsorption as a method of fractionation has been analogous to the development of distillation. In both cases the operation was originally carried out in a simple batch unit. After many years, rectification was added and close fractionation became possible. In the case of distillation this was done by adding a packed or bubble plate column to the still kettle. In the case of adsorption it involved the use of an adsorbent-packed column to obtain chromatographic separation, which gave a rectification effect. 

Electronic Components o Ne0H-FeS04 copreclpl tat Ion, settling t filter press batch unit for complexed metals. F 12, 21 Industry Survey, Site Visit... 

Galvanizing o llme-Fe2S precipitation P 32 Paper X Batch Unit... 

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