Static equipment

DNV 2002. DNV-RP-GlOl Recommended practice. Risk based inspection of offshore topsides static equipment Det Norske Veritas. 

Since the measurement of temperature and pressure is more accurate than concentration measurements. Van Ness recommended the measurement of Px-data at isothermal conditions. Indeed, today mainly isothermal Px-data are measured. In the cell of the static equipments the precise liquid composition is usually achieved by injection of the degassed liquids with the help of precise piston pumps. The change of the feed composition by evaporation can easily be taken into account, when the volume of the cell and the pressure is knowa Depending on the vapor volume the change of the feed composition is smaller than 0.1 mol% at moderate pressures. By this method a much more precise determination of the liquid composition is achieved than by analytical measurements. The measurement of the pressure and the temjrerature can be realized very precisely. 

The designs of static equipment for sampling described further can be grouped into three types according to how temperature and pressure in the reaction volume and in the sampler (or in the equilibrium mixture and the sample) are... 

Separators are the most important static equipment used in chemical industries. These are principally used to separate vapor from liquid phase the liquid phase can be a single continuous phase or a mixture of two immiscible phases. Both horizontal and vertical separators are extensively used in industries, and some typical applications include the following ... 

Damping reduces the transmissibihty at the natural frequency, but increases the transmissibihty at higher frequencies. The natural frequency of isolators made from most materials also can be expressed as a function of the static deflection of the isolator due to the load imposed by the supported equipment that is, / = 5/v where 5 is the static deflection of the isolator, cm (5). 

Products. Vibration isolators typically are selected to have a static deflection, under load, that yields a natural frequency no more than one-third the lowest driving frequency that must be isolated (see Eig. 7). The supporting stmcture must have sufficient stiffness so it does not deflect under the load of the supported equipment by more than one-tenth the deflection of the isolator itself (6). In addition to static deflection requirements, vibration isolators are selected for a particular appHcation according to their abiHty to carry an imposed load, and to withstand the environment in which they are used (extreme temperatures, chemical exposure, etc). 

Safety considerations for magnetic resonance (mr) experiments have received Htde attention except for the problems associated with the use of electronic devices such as pacemakers in the magnetic field. However, in a 1990 study of reproductive health involving more than 1900 women working in clinical mr facihties in the United States no substantial differences were reported between the group of women directly involved with mr equipment (280 individuals) and other working women (894 individuals) (10). Conclusions are restricted to exposure to the static external field. 

This ranking implies that human errors are more likely to occur than active equipment failures (functioning equipment, such as a mnning pump) and that active equipment failures are more likely to occur than passive equipment failures (static, nonfunctioning equipment, such as a storage tank). 

Cavitation Loosely regarded as related to water hammer and hydrauhc transients because it may cause similar vibration and equipment damage, cavitation is the phenomenon of collapse of vapor bubbles in flowing liquid. These bubbles may be formed anywhere the local liquid pressure drops below the vapor pressure, or they may be injected into the hquid, as when steam is sparged into water. Local low-pressure zones may be produced by local velocity increases (in accordance with the Bernouhi equation see the preceding Conservation Equations subsection) as in eddies or vortices, or near bound-aiy contours by rapid vibration of a boundaiy by separation of liquid during water hammer or by an overaU reduction in static pressure, as due to pressure drop in the suction line of a pump. 

Equation (11-48) is applicable to burdens in the solid, liquid, or gaseous phase, either static or in laminar motion it is apphcable to solidification equipment and to divided-solids equipment such as metal belts, moving trays, stationaiy vertical tubes, and stationaiy-shell fluidizers. 

Conveyor-Belt Devices The metal-belt type (Fig. 11. 55) is the only device in this classification of material-haudhug equipment that has had serious effort expended on it to adapt it to indirecl heat-transfer seiwice with divided solids. It features a lightweight construction of a large area with a thin metal wall. ludirect-coohiig applications have been made with poor thermal performance, as could be expected with a static layer. Auxihaiy plowlike mixing devices, which are considered an absolute necessity to secure any worthwhile results for this seiwice, restrict applications. 

Belt Presses Belt presses were fiiUy described in the section on filtration. The description here is intended to cover only the parts and designs that apply expression pressure by a mechanism in adchtion to the normal compression obtained from tensioning the belts and pulling them over rollers of smaller and smaller diameters. The tension on the belt produces a squeezing pressure on the filter cake proportional to the diameter of the rollers. Normally, that static pressure is calculated as P = 2T/D, where P is the pressure (psi), T is the tension on the belts (Ib/hnear in), and D is the roller diameter. This calculation results in values about one-half as great as the measured values because it ignores pressure created by drive torque and some other forces [Laros, Advances in Filtration and Separation Technology, 7 (System Approach to Separation and Filtration Process Equipment), pp. 505-510 (1993)]. 

Toluene is a notoriously poor electrical conductor even in grounded equipment it has caused several fires and explosions from static electricity. Near normal room temperature it has a concentration that is one of the easiest to ignite and, as previously discussed, that generates maximum explosion effects when ignited (Bodurtha, 1980, p. 39). Methyl alcohol has similar characteristics, but it is less prone to ignition by static electricity because it is a good conductor. Acetone is also a good conductor, but it has an equihbrium vapor pressure near normal room temperature, well above UFL. Thus, acetone is not flammable in these circumstances. 

Bv this method, in general, the expecl ed inherent maximum explosion overpressure of the order P = 7 to 10 bar will be reduced to a value of Pred.max < 2 bai. In this case, the static activation overpressure of the venting device is < 0.1 bar. The resulting P,ed,max i i y not exceed the design pressure of the equipment. The explosion as such is not prevented only the dangerous consequences are limited. However, subsequent fires must be expecl ed. 

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