Total containment, chemical plant design

Often this low reactive content can lead to designing for total containment i.e., no relief system is required by which further emission reductions are achieved. Moreover, the diffusive emissions (smell) can be reduced by reducing the number of flanges and valves. Because the size of the plant will also be reduced, it is likely that the social status of a chemical plant can be raised by the introduction of process intensification. 

Plant name Type PWR Designer Op. date Thermal power (MWth) (core/total) Containment type Free volume (min/max) Sprays (borated water +-2500 ppm, except for Tihange 1 2700ppm) Qualified containment cooling (Doel) Containment sump chemical additives... 

As a rule, the reactor is followed by several separation steps. The required number of separations is equal to the number of components to be separated minus one. This is the reason that a chemical plant contains as a rule many more separators than reactors. This is also reflected in the total cost of the equipment. Since the reaction conditions generally influence the composition of the reactor product and consequently determine the train of separations that follows, the reactor should not be designed without considering the consequences for the separations. Various aspects of Uiis problem will be indicated briefly below. 

One of the most important factors that determines the column configuration is the formulation (or goals) of the separation task with respect to the total flow sheet. Although a mixture may consist of C components, it does not mean that all C products are necessary. The components contained in streams recycled into the process (e.g., unreacted reactants recycled to the reactor) usually do not have to be separated from each other. Also separation of streams that are later mixed (blended) should be avoided, if possible. The separation system needs to be optimized together with the entire plant, either simultaneously or in a hierarchical approach, as described by Douglas (The Conceptual Design of Chemical Processes, McGraw-ffill, New York, 1988). 

Recently, Contos et al. (50) and McCandless and Contos (51) have made a comprehensive assessment of the economics of the major chemical coal cleaning processes. Since pilot plant data were not available for most processes, the costs were based on preliminary conceptual designs. Taking bituminous coal from the Pittsburgh seam as a representative coal (which contained 1.93 wt% total sulfur, about 66% of which was pyritic sulfur), capital and operating costs for a feed rate of 7,200 metric ton/day plant were evaluated based on the first quarter of 1977 prices. A brief summary of their study is shown in Table 2. 

This manual is intended for the practising chemist who has to do a job in analysing plant material. Therefore, the present manual only contains ready-to-hand procedures without any comment. The procedures described are only for inorganic components, which frequently occur in the plant. Most procedures are designed to give a total content value of the element under consideration, regardless of the chemical structure in which it occurs in the plant. 

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