Containers vessel

Carbon disulphide should never be used if any alternative solvent is available, as it has a dangerously low flash-point, and its vapours form exceedingly explosive mixtures with air. Ether as a solvent for recrystallisation is much safer than carbon disulphide, but again should be avoided whenever possible, partly on account of the danger of fires, and partly because the filtered solution tends to creep up the walls of the containing vessel and there deposit solid matter by complete evaporation instead of preferential crystallisation. 

The diazomethane-ether solution should be dry. If in doubt, it may be dried with A.R. potassium hydroxide pellets. The anhydrous ethereal solution may be stored in a smooth glass flask or bottle in a refrigerator for a week or so since slow decomposition occurs with hberation of gas, the containing vessel should be protected by a calcium chloride (or cotton wool) guard tube. 

ASME Code Sec. Ill Nuclear Power Plant Components This section of the code includes vessels, storage tanks, and concrete containment vessels as well as other nonvesseJ items. 

Fluidization, or fluidizing, converts a bed of solid particles into an expanded, suspended mass that has many properties of a liquid. This mass has zero angle of repose, seeks its own level, and assumes the shape of the containing vessel. 

Bubble growth will be hmited by the containing vessel and the bubble hydrodynamic stability. Bubbles in group-B systems can grow to several meters in diameter. Bubbles in group-A materials with high fines may reach a maximum stable bubble size of only several cm. 

A simplified process flow sheet showing containment vessels, major piping, and quantity of chemicals... 

Pressure Relief Devices The most common method of overpressure protection is through the use of safety rehef valves and/or rupture disks which discharge into a containment vessel, a disposal system, or directly to the atmosphere (Fig. 26-13). Table 26-8 summarizes some of the device characteristics and the advantages. 

Multireactor Knockout Drum/Catch Tank This interesting system, depic ted in Fig. 26-22, is sometimes used as the containment vessel for a series of closely spaced reac tors (Speechly et al., Trinci-ples of Total Containment System Design, presented at I. Chem. E Noith West Branch Meeting, 1979). By locating the drum as shown in Fig. 26-22, minimum-length vent lines can be routed direc tly to the vessel without any bends. 

FIG. 26-22 Multireactor knockout (K-O) drum/catch tank a) plan view of reactors connected to horizontal containment vessel (h) back-to-back bursting disc assembly (c) elevation of self-supporting vessel (d) elevation of horizontal vessel on roof of building (e) elevation of horizontal vessel on side of building. 

Reactive System Screening Tool (RSST) The RSST is a calorimeter that quickly and safely determines reactive chemical hazards. It approaches the ease of use of the DSC with the accuracy of the VSP. The apparatus measures sample temperature and pressure within a sample containment vessel. Tne RSST determines the potential for runaway reactions and measures the rate of temperature and pressure rise (for gassy reactions) to allow determinations of the energy and gas release rates. This information can be combined with simplified methods to assess reac tor safety system relief vent reqiiire-ments. It is especially useful when there is a need to screen a large number of different chemicals and processes. 

This will also give conservative results. For heat input from fire to liquid containing vessels see Determination of Rates of Discharge. ... 

The heat input from fire is discussed in API RP 520 (Reference 4). One form of their equation for liquid containing vessels is... 

When the bubble diameter approaches the diameter of the containing vessel, slug flow is said to exist. In such cases, the bubble rise velocity is given by... 

Determining Vapor Loads from Liquid-Containing Vessels Exposed to Fire... 

A runaway reaction occurs when an exothermic system becomes uncontrollable. The reaction leads to a rapid increase in the temperature and pressure, which if not relieved can rupture the containing vessel. A runaway reaction occurs because the rate of reaction, and therefore the rate of heat generation, increases exponentially with temperature. In contrast, the rate of cooling increases only linearly with temperature. Once the rate of heat generation exceeds available cooling, the rate of temperature increase becomes progressively faster. Runaway reactions nearly always result in two-phase flow reliefs. In reactor venting, reactions essentially fall into three classifications ... 

Conservation Vent Valve A device designed to maintain pressure within preset limits in a liquid-containing vessel for the purpose of emissions reduction. It also provides protection against excessive pressure or vacuum. 

The pressure at which the valve is expected to open (set pressure) is usually selected as high as possible consistent with the effect of possible high pressure on die process as well as the containing vessel. Some reactions have a rapid increase in temperature when pressure increases, and this may fix the maximum allowable process pressure. In other situations the pressure rise above operating must be kept to some differential, and the safety valve must relieve at the peak value. A set pressure at the maximum value (whether maximum allowable working pressure of vessel, or other, but insuring protection to the weakest part of the system) requires the smallest valve. Consult manufacturers for set pressure compensation (valve related) for temperatures >200°F. 

Due to gas expansion from external fire, the API code [10] provides for calculation of the pressure relief valve orifice area for a gas containing vessel exposed to external fire on die unwetted surface ... 

Drilling barges, commonly employed in inland waters and marshes, can be used where water depths do not exceed about 25 ft. These self-contained vessels provide the least expensive drilling vessel, but have limited applicability because of water depth limitations. 

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