Horizontal vessel calculation

Once the menu Horizontal executes, the following form (Figure 1.22) will appear. This form is designed for horizontal vessel calculations. 

The general format of the Vertical vessel calculation is presented in Figure 1.24. General data entry and calculation principles are as discussed for the horizontal vessel calculation. However, the following points should be considered ... 

Example of Horizontal Vessel Rupture Calculation Method. 128... 

THREE PHASE HORIZONTAL VESSEL ANALYSIS CALCULATIONS Gas - Oil - Water Separation... 

The Vessize program next proceeds to calculate the required horizontal vessel lengths for gas bubble or foam separation from the oil phase. Water separation from the oil phase is also calculated in the following discussion... 

As the oil flows within its designated cross-section area through the horizontal vessel, free water droplets form and begin to drop at a terminal velocity rate. The Vessize program calculates this terminal velocity VTWO. As discussed previously in the oil dehydration section, the Stokes law settling equation is used for the water droplet fall rate VTWO. 

CALCULATE THE TOTAL CROSS-SECTIONAL AREA OF HORIZONTAL VESSEL, ft 2. 

THIS PROGRAM CALCULATES THE SEGMENTAL AREA OF A CIRLCE COUPLED WITH A MODIFIED DOOLITTLE FORMULA FOR DISHED HEADS TO CALCULATE PARTIAL VOLUMES OF HORIZONTAL VESSELS. 

To illustrate the preliminary design formulae and the time saved by using the standard form sheets, an example is worked out on the Vessel Calculation Form. Following the example, the derivation of the formulas is given. The forms may be used for horizontal vessels if the beam bending stress is used instead of wind stress and for riveted vessels if proper efficiencies are used for the joints. 

In spite of different procedures and design tools, we sometimes come across some typical design requirements that are not covered by any known procedure. Some imderstanding of basic mathematics and fundamental process engineering can solve a large number of problems without much difficulty. For example, a volume calculation of a horizontal vessel requires simple integration, volume calculation of an inclined vessel using Simpson s rule, etc. 

Vessel Siting The area needed for vapor disengaging is calculated by the equations given earlier in the section on horizontal blowdown drums. 

Thus, the calculated blast parameters at the large storage vessel are as follows a side-on peak overpressure of 63 kPa and a horizontal impulse of 233 Pa.s. 

The wetted area of the tank or storage vessel shall be calculated as follows For spheres and spheroids, the wetted area is equal to 55 percent of the total surface area or the surface area to a height of 30 feet (9.14 meters), whichever is greater. For horizontal tanks, the wetted area is equal to 75 percent of the total surface area For vertical tanks, the wetted area is equal to the total surface area of the shell within a maximum height of 30 feet (9,14 meters) above grade. 

The vessel is determined to be an uninsulated, horizontal, grade-level, cylindrical pressure vessel with a gas volume of 706 ft3 (20 m3). The vessel has a MAWP of 1,480 psig (102 bar) at 650°F (343°C) and a Minimum Design Metal Temperature (MDMT) of 40°F (4°C) since it is constructed of unnormalized steel material. Due to process conditions immediately prior to pressuring the vessel to 1,000 psig (69 bar), the vessel s metal temperature is approximately 30°F (-1°C). When the vessel is pressurized to 1,000 psig, it fails catastrophically. The distances to overpressure endpoints (1, 3, and 5 psig) are calculated as follows ... 

The recommended method is from Guidelines for Pressure Relief and Effluent Handling Systems (AIChE-CCPS, 1998). It is an improvement over the method presented in the 7th edition of this Handbook. The procedure involves calculating a terminal velocity for a selected droplet size, then providing enough residence time in the vapor space to allow the droplets to fall from the top of the vessel to the level of liquid collected. Also, the vapor velocity in the separator must not exceed the value above which liquid may Be entrained from the liquid surface in the separator. The tank is treated as a simple horizontal cylinder, neglecting the volume of liquid in the heads. 

Rotational fluid velocities are calculated since horizontal (rotational) flow prevails in the hydrodynamic regime within the dissolution vessels. Thus, the overall hydrodynamics and hence dissolution is dominated by the substantially higher rotational (tangential) fluid velocities. 

Calculation methods are given here for cases (a) to (c). In section A3.4 below, references are given to a calculation method for case (d). The level swell calculation methods presented here use the drift flux correlations developed by DIERS[11. The DIERS correlations apply to a vertical cylindrical vessel, which is most often the case for chemical reactors. Modifications for horizontal cylindrical vessels are given by Sheppard[2,3]. 

To account for the extra weight due to nozzles, manholes, and skirts or saddles, increase the weight calculated for the smooth vessel including top and bottom by 1.5% for vessels to be installed in a horizontal position and by 20% for vessels to be installed in a vertical position. 

In a recent work, Aiba (A2) studied the flow currents in water, in a mixing vessel 14 in. in diameter, using an axially-mounted two-bladed flat paddle 4.7 in. in diameter. Measurements were made both without baffles and with four baffles %2 tank diameter wide. A sphere about 6 mm. in diameter was suspended by a flexible wire, and its displacement from the equilibrium (no-flow) position was measured. To get the horizontal displacement, cobalt-60 was embedded in the sphere, and a Geiger-Mueller counter approximately 10 mm. in diameter was immersed in the tank 2-5 cm. from the sphere. The vertical movement of the sphere was measured with a cathetometer, and its angular position observed by eye. From the known components of displacement and the assumed drag coefficient of the sphere, values of the radial, tangential, and vertical components of the flow around the sphere were calculated. 

According to Stein and Schmidt a few adaptations make it possible to use correlations for horizontal tube coils to estimate heat transfer in a vessel with a halfpipe jacket. Necessary adaptations include using the thermic diameter dth = Tt/2)di instead of the tube inner diameter d to calculate the Reynolds and Nusselt numbers, and replacing the bending ratio (dhjDb) with the ratio of d-J2 T + 26 ) " ... 

Cylindrical vessels and horizontal tanks are used for the storage of fluids in the chemical process industries. Various level instruments are employed to determine the liquid level in process vessels. The exact liquid volume can be obtained either by calibration of the vessels or by tedious calculations. Partial volumes for horizontal, cylinders with flat, dished, elliptical, and hemispherical ends, and for vertical cylinders are employed for storing process fluids. 

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