Calculation Example

Table 4.23 Example calculation of the hydrate formation temperature for a natural gas at 80 bar abs. Result = 29.1 "C. ...

If the dependence on temperature as well as on composition is known for a solution, enthalpies and entropies of adsorption may be calculated from the appropriate thermodynamic relationships [82]. Neam and Spaull [147] have, for example, calculated the enthalpies of surface adsorption for a series of straight-chain alcohols. They find an increment in enthalpy of about 1.96 kJ/mol per CH2 group. 

The BIOh- force field option in HyperChem has no hydrogen bonding term. This is consistent with evolution and common use of the CHARMM force field (even the 1983 paper did not use a hydrogen bonding term in its example calculations and mentioned that the functional form used then was unsatisfactory and under review). 

The drop in pressure when a stream of gas or liquid flows over a surface can be estimated from the given approximate formula if viscosity effects are ignored. The example calculation reveals that, with the sorts of gas flows common in a concentric-tube nebulizer, the liquid (the sample solution) at the end of the innermost tube is subjected to a partial vacuum of about 0.3 atm. This vacuum causes the liquid to lift out of the capillary, where it meets the flowing gas stream and is broken into an aerosol. For cross-flow nebulizers, the vacuum created depends critically on the alignment of the gas and liquid flows but, as a maximum, it can be estimated from the given formula. 

UNIFAC andASOG Development. Pertinent equations of the UNIQUAC functional-group activity coefficient (UNIFAC) model for prediction of activity coefficients including example calculations are available (162). Much of the background of UNIFAC involves another QSAR technique, the analytical solution of groups (ASOG) method (163). 

Table 9-15 shows that the total amount of tax actually paid over the 5-year period was 988,320. This becomes 5.34,272 in uninflated-money terms when the tax for each year is corrected to its purchasing power in Year 0, using / factors for the 20 percent inflation rate employed for the example. Calculations for other rates of inflation can also be made, and the results plotted as in Fig. 9-.30. 

Example - calculation of reliability using different loading cases... 

For sampling a relatively small number of sources, a simplified calculation form may be used. Such forms enable the office personnel to perform the arithmetic necessary to arrive at the answers, freeing the technical staff for proposals, tests, and reports. Many of the manufacturers of source-testing equipment include example calculation forms as part of their operating manuals. Some standard sampling methods include calculation forms as a part of the method (8). Many control agencies have developed standard forms for their own use and will supply copies on request. 

Example. Calculate the hydrate temperature for the following conditions ... 

Example. Calculate the change in Gibbs free energy for the reaction of methanol and oxygen to produce formaldehyde and water at reaction temperatures of 600, 700, 800, 900, and 1,000°K ... 

Example Calculate the dry flare header size, which is connected to the above knock-out drum. Previously noted conditions remain the same. Additional data are ... 

Example 3.10 If a moment of Af, = 100 Nm/m is applied to the unidirectional composite described in the previous Example, calculate the curvatures which will occur. Determine also the stress and strain distributions in the global and local (1-2) directions. 

It is concluded that such simple gas turbines with WHRs have good energy utilisation at Acg I with respectable FESR. The introduction of a WHB will move the operable area to higher values of A, usually with comparable EUFs but lower FESRs, as has been illustrated in the examples calculated in Section 9.2. 

In these cases, the product is reslurried with pure liquor or fresh solvent if the solubility is not too high, and refiltered. In order to meet the required product impurity level, several such washings may take place in series. See Coulson and Richardson (1991) and Mullin (2001) for design guides and examples calculations. It is noted that impurities retained within liquid occlusions are particularly difficult to remove without first crushing the crystals. 

Typical example calculations are given in Randolph and Larson (1988) and Larson and Garside (1973). 

Table 4-1 is an example calculation of the temperature below which hydrates will form at the 4,000 psia flowing temperature for the example gas composition of Table 1-1. From this calculation, hydrates will form at temperatures below 74°F.

This section first presents literature review on pressure vessel bursts and BLEVEs. Evaluation of energy from BLEVE explosions and pressure vessel bursts is emphasized because this value is the most important parameter in determining blast strength. Next, practical methods for estimating blast strength and duration are presented, followed by a discussion of the accuracy of each method. Example calculations are given in Chapter 9. 

The head losses calculated using K coefficients by these figures can be added directly to the total friction head loss for the straight pipe portions of a system. When equivalent lengths are determined, they must be added to the straight pipe before determining the total head loss, as shown in the example calculations for a water system. 

---