Auxiliary equipment continued

If the program continues and additional reductions are desired, more expensive and more complex projects begin to emerge (Phase II). These are often associated with equipment modifications, process modifications and process control and may include the addition or adaptation of auxiliary equipment for simple source treatment, possibly for recycle. This phase usually has little immediate ROI, and more inclusive approaches to assessing the economics of the operation (estimating costs for waste handling, long-term liability, risk) are needed to justify the continued pollution-prevention operation. 

With respect to the re-deposition of a coating on the first wall, the obvious advantage is the compatibility with Tokamak operation since it requires a minimum of auxiliary equipment and modification, particularly if a continuous, high frequency discharge is used. The power requirements for such an approach appear to be acceptable134. An rf heating system, if incorporated into the reactor design (e. g. 

A cell for continuous flow operation must be designed with a high electrode surface-electrolyte volume ratio, provided with a feeding system, and, last but not least, connected with suitable auxiliary equipment for continuous removal of the product s) of electrolysis and reestablishment of the electrolyte composition. The continuous workup procedure during electrolysis is somewhat inconvenient in the laboratory, and consequently small continuous flow cells have mostly been operated with recycling to a reservoir before scaling up. Large cells and their industrial applications are discussed in Chapter 31. 

AUXILIARY EQUIPMENT. The dispersed phase in an extraction tower is allowed to coalesce at some point into a continuous layer from which one product stream is withdrawn. The interface between this layer and the predominant continuous phase is set in an open section at the top or bottom of a packed tower in a sieve-plate tower it is set in an open section near the top of the tower when the light phase is dispersed. If the heavy phase is dispersed, the interface is kept near the bottom of the tower. The interface level may be automatically controlled by a vented overflow leg for the heavy phase, as in a continuous gravity decanter. In large columns the interface is often held at the desired point by a level controller actuating a valve in the heavy-liquid discharge line. 

Some industrial chemical processes involve no chemical reactions but only operations for separating chemicals and phases together with auxiliary equipment. A typical process is shown in Fig. 1.3, where wet natural gas is continuously separated into light paraffin hydrocarbons by a train of separators including an absorber, a reboiied absorber, and five distillation columns. Although not shown, additional separation operations may be required to dehydrate and sweeten the gas. Also, it is possible to remove nitrogen and helium, if desired. 

The required operating capacity of a proposed facility is too small to permit continuous operation at a practical rate. Pumps, boilers, piping, instrumentation, and other auxiliary equipment generally have a minimum industrial operating capacity. 

The evaluation of photocatalytic reactor performance is closely related to the continuous evaluation and reassessment of lamp operation since lamps experience decay with time of utilization. It is recommended that lamps be calibrated and re-recalibrated frequently to estimate their decay. In addition, it is advised to use some auxiliary equipment in perfonning this task (a) a UVX digital radiometer, (b) a 4D Controls Ltd spectrora-diometer, (c) the Lamp Testing Unit (LTU) developed by Serrano and de Lasa (1997), and (d) a set of tubulai collimators for radiation ti ansmission measurements. 

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