First Trial

Throughout this trial, vapor and liquid loads and physical properties are taken from Table 6.10. Tray layout parameters are taken from Table 6.11. 

Hooding check. It was recommended (5,30,82) to design a column m 80 to 85 percent of flood. This safety margin allows for inaccuracies la data and correlations. In addition, a drop in efficiency often occurs ju before the flood point, and this practice avoids the problem region. Tha flooding check is performed using the Kister and Haas correlataas (Sec. 6.2.6). 

Downcomer check. Use the Koch correlation (Sec. 6.2.9), which is the more conservative correlation for downcomer design according to Lockett s analysis (12). 

Summary, According to the above criteria, the tower appears oversized. The next trial should be performed with a smaller tower diameter, say 6 ft. 

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TABLE 13-12 Stage Compositions from the First Trial of Example 3... 

Integration is by successive approximation, using essentially Eulers method. For the first trial. 

For first trial on tubeside assume equal heat is transferred in each pass w ith constant fluid heat capacity. 

For a first trial at sizing or for estimates, the Equation 3.13 can be differentiated and solved for P , with the result,... 

If Equation 3.12 is borrowed from the reciprocating compressor chapter and used for an uncooled section, the pressure ratio per section may be calculated assuming an approximate equal-work division. For the first trial, assume the limit of temperature may be achieved in two sections. 

As a first trial, an inside pipe diameter is assumed based on 60 percent of the sonic velocity corresponding to the pressure and temperature at the base of the stack, i.e., at 2 psig and temperature =T (upstream temperature since isothermality is assumed). 

For final calculation use from Figures 7-23 or 7-24 and substitute in the above equation. Determine the needed Reynolds number, Re, using the next size larger orifice. Area is determined from that made in the first trial calculation [33]. 

Use same fouling factors as for first trial. Overall coefficient. 

From standard tubesheet layout or Table 10-9, select a 10-in. I.D. shell with 30 tubes, 2 passes, for first trial. 

For the first trial, assume 39% vaporization per pass. From Figures 10-114and 10-116 and for i i = 0.49,... 

For the first trial, assume 15% vaporization per pass. This gives a circulation rate of 91,300 Ib/hr or 25.4 Ib/sec. For this rate, the following apply ... 

During the first trials with synthetic separators around 1940 it had already been observed that some of the desired battery characteristics were affected detrimentally. The cold crank performance decreased and there was a tendency towards increased sulfation and thus shorter battery life. In extended test series, these effects could be traced back to the complete lack of wooden lignin, which had leached from the wooden veneer and interacted with the crystallization process at the negative electrode. By a dedicated addition of lignin sulfonates — so called organic expanders -— to the negative mass, not only were these disadvantages removed, but an improvement in performance was even achieved. 

First trials with CD3 antibodies for therapy of autoimmune diseases (insulin-dependent diabetes mellitus psoriatic arthritis... 

Autocatalysis, although not rare, is not common either. A study of this phenomenon is crucial for the treatment of oscillating reactions, which are presented in Section 8.8. If the data give an indication of autocatalytic behavior, one quick laboratory test is to use the leftover solution from a completed reaction as the solvent for the next. If the replicate is faster than the first trial, autocatalysis is suggested. 

From the vapour pressures it can be seen that the EDC and water will be essentially totally condensed, and that the ethylene remains as vapour. Ethylene will, however, tend to be dissolved in the condensed EDC. As a first trial, assume all the ethylene stays in the gas phase. 

As a first trial, assume that all the water in the inlet stream is condensed, then ... 

As a first trial, all the water vapour was assumed to condense this assumption will now be checked. 

The values of the split-fraction coefficients will depend on the function of the processing unit and the constraints on the stream flow-rates and compositions. Listed below are suggested first trial values, and the basis for selecting the particular value for each component. 

The relative volatility will change as the compositions and (particularly for a vacuum column) the pressure changes up the column. The column pressures cannot be estimated until the number of stages is known so as a first trial the relative volatility will be taken as constant, at the value determined by the bottom pressure. 

It is necessary to estimate the composition of the non-keys so that they can be included in the stage calculations. As a first trial the following values will be assumed ... 

Before a heat balance can be made to estimate Z., and V2, an estimate of y2 and T2 is needed. y2 is dependent on the liquid and vapour flows, so as a first trial assume that... 

It will be necessary to estimate the concentration of the non-key components in the bottom product as a first trial take ... 

To calculate the column diameter an estimate of the net area An is required. As a first trial take the downcomer area as 12 per cent of the total, and assume that the hole-active area is 10 per cent. 

As first trial take downcomer area as 12 per cent of total. Column cross-sectioned area... 

As a first trial take the mean temperature of the crude oil as equal to the inlet temperature, 40°C specific heat capacity at this temperature = 2.01 kJ/kg°C. 

As a first trial take the baffle spacing = Ds/5, say 100 mm. This spacing should give good heat transfer without too high a pressure drop. 

As a first trial, divide the column into five sections (courses), with the thickness increasing by 2 mm per section. Try 10, 12, 14, 16, 18 mm. 

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