Pressure system data

Use of Psychrometric Charts at Pressures Other Than Atmospheric The psychrometric charts shown as Figs. 12-1 through 12-4 and the data of Table 12-1 are based on a system pressure of 1 atm (29.92 inHg). For other system pressures, these data must be corrected for the effect of pressure. Additive corrections to be apphed to the atmospheric values of absolute humidity and enthalpy are given in Table 12-2. 

For mixtures containing more than two species, an additional degree of freedom is available for each additional component. Thus, for a four-component system, the equihbrium vapor and liquid compositions are only fixed if the pressure, temperature, and mole fractious of two components are set. Representation of multicomponent vapor-hquid equihbrium data in tabular or graphical form of the type shown earlier for biuaiy systems is either difficult or impossible. Instead, such data, as well as biuaiy-system data, are commonly represented in terms of ivapor-liquid equilibrium ratios), which are defined by... 

Determine the vent size for a vapor pressure system using the following data and physical properties. 

Nevertheless, in many cases, mean wind velocities can be assumed. In ventilation-system reliability studies, e.g., where minimum ventilation rates are to be determined, a calm situation with little wind must be assumed anyhow, and the need for accurate wind pressure coefficient data is not so obvious. 

Pressure loss in a piping system (not including the tanks, heat exchangers, distillation columns, etc.) is usually expressed in units oi feet of flowing fluid, or the equivalent converted to pounds per square inch. Some published pressure loss data is expressed as per 100 equivalent feet of the size pipe being used or estimated. 

Figure 9-50. HETP and pressure drop data for a typical distillation system. Packing equivalent to X-200 (8 strands), stainless steel. System methylcyclohexane and toluene. Reflux Ratio 100%. Column Diameter 18 inches. Packed Height 5 feet. Used by permission ACS Industries, Inc., Separation Technology Division, Bull. B-129 (1992).

Total Pressure Loss. Using Table 4-110 and Equations 4-150 and 4-151, the pressure loss across the turbine motor can be determined for the various circulation flowrates and the mud weight of 16.2 Ib/gal. These data together with the above bit pressure loss data are presented in Table 4-113. Also presented in Table 4-113 are the component pressure losses of the system for the various circulation flowrates considered. The total pressure loss tabulated in the lower row represents the surface standpipe pressure when operating at the various circulation flowrates. 

For gas-liquid solutions which are only moderately dilute, the equation of Krichevsky and Ilinskaya provides a significant improvement over the equation of Krichevsky and Kasarnovsky. It has been used for the reduction of high-pressure equilibrium data by various investigators, notably by Orentlicher (03), and in slightly modified form by Conolly (C6). For any binary system, its three parameters depend only on temperature. The parameter H (Henry s constant) is by far the most important, and in data reduction, care must be taken to obtain H as accurately as possible, even at the expense of lower accuracy for the remaining parameters. While H must be positive, A and vf may be positive or negative A is called the self-interaction parameter because it takes into account the deviations from infinite-dilution behavior that are caused by the interaction between solute molecules in the solvent matrix. 

Leu and Robinson (1992) reported data for this binary system. The data were obtained at temperatures of 0.0, 50.0, 100.0, 125.0, 133.0 and 150.0 °C. At each temperature the vapor and liquid phase mole fractions of isobutane were measured at different pressures. The data at 133.0 and 150.0 are given in Tables 14.9 and 14.10 respectively. The reader should test if the Peng-Robinson and the Trebble-Bishnoi equations of state are capable of describing the observed phase behaviour. First, each isothermal data set should be examined separately. 

Figure 7.5 Variation of equilibrium oxygen partial pressure (a) equilibrium between a metal, Ag, and its oxide, Ag20, generates a fixed partial pressure of oxygen irrespective of the amount of each compound present at a constant temperature (b) the partial pressure increases with temperature (c) a series of oxides will give a succession of constant partial pressures at a fixed temperature and (d) the Mn-O system. [Data from T. B. Reed, Free Energy of Formation of Binary Compounds An Atlas of Charts for High-Temperature Chemical Calculations, M.I.T. Press, Cambridge, MA, 1971.]...

The average dT/dt is typically an arithmetic average between the value at set pressure and the value at peak allowed pressure. The properties Cp, hfg, i, either can be evaluated at the set conditions or can be taken as the average values between the set condition and the peak allowed pressure condition. Alternatively, the term h/g/t)/g in Eq. (23-95) can be replaced by T(dP/dT)tat via the Clapeyron relation. This holds reasonably well for a multicomponent system of near constant volatility. Such an application permits direct use of the experimental pressure-temperature data obtained from a closed-system runaway VSP2 test. This form of Eq. (23-95) has been used to demonstrate the advantageous reduction in both vent rate and vent area with allowable overpressure (Leung, 1986a). 

As a means of verifying the model parameters of Table II, the osmotic coefficient was calculated from isopiestic vapor pressure measurement data (17) for the KCl-KBr-H20 system at 25°C (Table III). 

This method is based on the principle of capillary equilibrium, providing a nondestructive technique in which the total porosity and capillary pressure-saturation data are measured [198,199]. The idea is that when two partially saturated porous materials are in contact, the system moves toward an equilibrium state in which the capillary pressure of a liquid in one of fhe samples is the same for fhe ofher material. 

A portable electronic data acquisition system was transported to the plant site and connected to the extruder panel. All available instrument outputs from the panel were connected in parallel with the acquisition system. Data collected included barrel zone temperatures, screw speed, motor current, pressure at the entry to the pump, transfer line temperature, and gear pump temperature. Process data were collected at a frequency of once every five seconds. 

Sinor, J.E. and Weber, J.H. Vapor liquid equilibria at atmospheric pressure. Systems containing ethyl alcohol, n-hexane, benzene, and methylcyclopentane, J. Chem. Eng. Data, 5(3) 243-247, 1960. 

The majority of commercial developments which relate to the automation of GC and HPLC pay little attention to sample preparation. There are few examples where pretreatment is not required. A fully automated system was developed by Stockwell and Sawyer [23] for the determination of the ethanol content of tinctures and essences to estimate the tax payable on them. An instrument was designed and patented which coupled the sample pre-treatment modules, based on conventional AutoAnalyzer modules, to a GC incorporating data-processing facihties. A unique sample-injection interface is used to transfer samples from the manifold onto the GC column. The pretreated samples are directed to the interface vessel hy a simple hi directional valve. An ahquot (of the order of 1 ml) can then he injected on to the GC column through the capillary tube using a time-over pressure system. 

Analysis of the pressure versus temperature data for the tests (see Annex- 2) indicated that case (iii) generated permanent gas but that the other cases were vapour pressure systems. For a vapour pressure system, it is the rate of temperature rise at the relief pressure which, determines the relief system size. The relief pressure of 3 bara corresponds to a temperature of approximately TOO °C for cases (i), (ii) and (v)r and to approximately 80°C for case (iv). It can be seen from Table 3.1 that case (ii) gives the highest rate of temperature rise at that.temperature and is therefore the worst of the vapour pressure systems. 

A reactor has a volume of 2 m3. The worst case runaway reaction has been identified and the data from a suitable adiabatic, low thermal inertia test, with a thermal inertia ( ) of 1.05, is given in Figure 6.4. Under these conditions, the reactor would contain 793 kg of reactants. The reacting system is a vapour pressure system. It is desired to relieve the runaway via a safety valve, if possible, with a set pressure of 0.91 barg (relief pressure of 1.0 barg = 2.0 bara). Evaluate the required relief size for an overpressure of 30% of the absolute relief pressure, which gives a maximum pressure of 2.6 bara = 1.6 barg. 

Most of the data in equations (8.1) and (8.2) are obtained as for vapour pressure systems (see section 6.3). The required relief flow area, A, can be obtained from the required relief rate, W, using equation (5.1) ... 

In a closed test, the pressure measured is that due to the reacting system within the test cell. The pressure versus time and temperature versus time data can be used to obtain pressure versus temperature. The pressure can be corrected for the partial pressure of any pad gas to give the vapour pressure (see A2.7.1). This can be plotted on a Cox chart or Antoine plot (log pressure versus -1/ (temperature)). If the data fall on a straight line, the system is a pure vapour pressure system. If they do... 

A2.4 RELIEF SYSTEM SIZING DATA FOR VAPOUR PRESSURE SYSTEMS A2.4.1 General... 

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