Estimates, ballpark

For film coefficients many situations exist. Table 1 and Figure 1 give ballpark estimates of film resistance at reasonable design velocities. 

For liquid boiling the designer is limited by a maximum flux q/A. This handbook cannot treat this subject in detail. For most applications assuming a limiting flux of 10,000 will give a ballpark estimate. 

The actual reflux ratio that one pieks should be optimized from economics data. For a ballpark estimate use... 

This subsection will help you select the type of packing to use for your studies and gives typical HETP and HTU values for ballpark estimates when time is short. 

If Plant 5 in Table 9-5 is ignored, the cost estimates of Example 9-3 and those for the three other plants of Table 9-5 built in the late 1960s are within 17% of the average 16,400,000. This is very good for this type of estimate, since this method does not take into account any differences in the scope. It assumes everything is similar, which is obviously false. This is why this method cannot be expected to provide anything better than a ballpark estimate. 

PROBLEM 1.16 Calculate answers to the following problems, and check your solutions by making ballpark estimates. 

You can calculate this value without a calculator because it equals (16 X 10 2)/(8 X 10 5). The ballpark estimate of Qc agrees with the more exact value of Qc = 2.37 X 103. 

The ballpark estimates of Kf and K agree with the experimental values. 

The following unit costs provide ballpark estimates for civil work frequently encountered in chemical plant projects. Some have been obtained from contractors, others from published cost data, and the rest reflect the author s actual past experience. 

The following units can be used to develop ballpark estimates for the different components of fire protection systems. They include excavation and backfill. When used to estimate grassroots plants, the estimated total should be checked ... 

This shortcut technique is suggested for ballpark estimates of the piping account for liquid flow plants. It must be used together with Section 19.4 and confirmed with the factors in Table 10.1. 

Lacking the velocity profile we can only make a ballpark estimate of the COVr of the mixer. We can use the approach in Paul (2004, p. 440) and use the maximum cross channel ATs/Tavg as a measure of the COV thus, from Figure 10.35... 

Order of magnitude estimates ( ballpark estimate, guesstimate, Class 5 estimate ), accuracy typically +30-50%, usually based on the costs of similar processes and requiring essentially no design information. These are used in initial feasibility studies and for screening purposes. 

Values of the parameters a and n for some fuels and commodity chemical processes are given in Table 6.2. The costs in the Hydrocarbon Processing supplements are supplied by the technology vendors and are suitable for ballpark estimates only. 

Tables I-IV provide ballpark estimates of the temperature Tg (based pyrometry data) reached by the gaseous volatile pyrolysis products, and the residence time tg of the volatile products at temperature Tg. A comparison of the Odeillo data with earlier Princeton research (1-3) using similar gas phase conditions (but much lower solid1s heating rates) is given in Tables I-IV. Since the Odeillo reactor did not provide for good control of the gas phase conditions, the relative agreement of the two sets of results given in Tables I-IV is as good as could be expected.

The ideal sampling and analytical procedures provide accurate assessment of both the quantity and nature of the material present at a given time point, and the sensitivity of the method must be capable of producing data of practical significance. Preliminary prediction from existing data or physicochemical modelling can give ballpark estimates of the likely... 

The following contains some interesting ballpark estimates which necessarily arise when discussing the world energy situation, in particular in connection with a future large-scale hydrogen energy economy ... 

Other semi-theoretical approaches to the problem of predicting reaction activation energies exist (22-24). For our purposes, however, it is sufficient to recognize that ballpark estimates are the best one can expect. Such estimates are often adequate for purposes of differentiating between alternative mechanisms on the basis of a comparison of predicted and actual activation energies. 

Check Because the mass we began with is less than a mole, there should he fewer than 6.02 X 10 molecules in the sample, which means the magnitude of our answer is reasonable. We can make a ballpark estimate of the answen 5/200 = 2.5 X 10 mol 2.5 X 10 X 6 X 10 = 15 X 10 = 1.5 X 10 molecules. The units (molecules) and significant figures (three) are appropriate. 

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