Base cases

25molm s at the outlet (Fig. 6.5a). The calculated reaction rate is lower but of the same order as the results found by Lehnert et al. (2000), as the simulation temperature in their study (1123 K) was higher than in the present study. The increase in DIR reaction rate is mainly caused by an increase in the SOFC temperature along the flow channel (Fig. 6.6), which will be 

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Take an example of estimating gross rock volume, based on seismic data and the results of two wells in a structure (Fig. 7.2). The following cross-section has been generated, and a base case GRV has been calculated. 

The econom/c mode/for evaluation of investment (or divestment) opportunities is normally constructed on a computer, using the techniques to be introduced in this section. The uncertainties in the input data and assumptions are handled by establishing a base case (often using the best guess values of the variables) and then performing sensitivities on a limited number of key variables. 

The uncertainty may be addressed by constructing a base case which represents the most probable outcome, and then performing sensitivities around this case to determine which of the inputs the project is most vulnerable to. The most influential parameters may then be studied more carefully. Typical sensitivities are considered in Section 13.7, Sensitivity Analysis . 

For any one case, say the base case, the project cashflow is constructed by calculating on an annual basis the revenue items (the payments received by the project) and then subtracting the expenditure items (the payments made by the project capex, opex and host government take). For each year the balance is the annual cash surplus (or cash deficit). Flence, on an annual basis... 

As discussed in Section 13.2, the technical, fiscal and economic data gathered to construct a project cashflow carry uncertainty. An economic base case is constructed using, for example, the most likely values of production profile and the 50/50 cost estimates, along with the best estimate of future oil prices and the anticipated production agreement and fiscal system. 

In order to test the economic performance of the project to variations in the base case estimates for the input data, sensitivity analysis is performed. This shows how robust the project is to variations in one or more parameters, and also highlights which of the inputs the project economics is more sensitive to. These inputs can then be addressed more specifically. For example if the project economics is highly sensitive to a delay in first production, then the scheduling should be more critically reviewed. 

It is useful to truncate the lines at the extreme values which are considered likely to occur, e.g. oil price may be considered to vary between -40% and +20% of the base case consumption. This presentation adds further value to the plot. 

We shall use these data and the accompanying information of Table 9-5 as the base case and calculate for straight-line depreciation the net present value (NPV) with a 10 percent discount factor and the discoiinted-cash-flow rate of return (DCFRR) for the project with the following situations. 

With a cost of capital of 10 percent the various cash flows can be discounted and summed. Thus for the base cases Z Af = 2,815,600, Z Ajp/d = 754,716, Z Aofd = 614,457, and Z C c/d = 61,446. With corporate taxes payable at 50 percent the aftertax cash flows of the first three items are (1 — 0.50) of the sums calculated above. The discounted working capital and the fixed-capital outlay are not subject to tax. These most probable values are listed and summed in Table 9-11 and, after adjustment for tax, give the modal value of the (NPV) as 276,224. 

The Smith-Brinkley Method uses two sets of separation factors for the top and bottom parts of the column, in contrast to a single relative volatility for the Underwood Method. The Underwood Method requires knowing the distillate and bottoms compositions to determine the required reflux. The Smith-Brinkley Method starts with the column parameters and calculates the product compositions. This is a great advantage in building a model for hand or small computer calculations. Starting with a base case, the Smith-Brinkley Method can be used to calculate the effect of parameter changes on the product compositions. 

The Smith-Brinkley Method can therefore be used to generate a hand base case beginning with either a heat and material balanced plant case, a rigorous computer solution of a plant case, or computer solution of a design case. Once the hand base case is established, alternate cases can be done by hand (or small computer having limited core) using the Smith-Brinkley Method. 

Problem Stripper computer simulation for a base case did not match test data. Proper simulation was needed for revamp design checking. 

The linear program can be designed to deliver a wealth of base case information, such as ... 

Insight into the economics of limited excursions from the optimized base case... 

After the base case is digested and accepted by the designer as valid, various modification cases can be obtained. Because the base case and each modification case is presented in its best light (at the optimum plant operation for that case), bias between cases is eliminated. Therefore, the designer can compare cases on the same basis. 

Although we did not discuss this, you should be able to readily identify commercial adsorbents that can compete with activated carbon in water treatment applications. What are they, what are their properties, and how do unit costs compare In performing the cost analysis, take into consideration the volumes of adsorbents needed to achieve comparable degrees of water treatment. To do this, you should develop a base case scenario. 

Bcise Update - overwrites all base case (original) data with the alternate (curr ase for the... 

Edit Accident Sequence Logic 2 Edit Base Case System Failure Probabilities... 

The initial aim of the procedure is to generate a reasonable base case design that can be used for preliminary economic evaluation of the process. This can subsequently be optimized and/or compared with any process alternatives that are identified. The complete process is always considered at each decision level, but additional fine detail is added to the structure of the flowsheet at any stage. Established heuristics and equipment selection procedures are used together with new process synthesis insights to guide each flowsheet decision. 

To evaluate the economics of this process, a cost model has been developed to estimate the separation costs for a specific racemate [68, 69]. For this purpose, the sensitivity of the separation costs for several key process parameters have been established as compared to a base-case separation in which a purity of 99 % is required at an enantioselectivity of 1.15. The maximum solubility of the drug is set... 

Figure 14.7 shows how pH changes when fifty milliliters of one molar NH3 is titrated with one molar HO. In many ways, this curve is the inverse of that shown in Figure 14.6 for the weak add-strong base case. In particular—... 

Kw0 is taken as the base case Kw. Kwa is the observed Kw for each size. 

Table II summarizes the yields obtained from the CONGAS computer output variable study of the gas phase polymerization of propylene. The reactor is assumed to be a perfect backmix type. The base case for this comparison corresponds to the most active BASF TiC 3 operated at almost the same conditions used by Wisseroth, 80 C and 400 psig. Agitation speed is assumed to have no effect on yield provided there is sufficient mixing. The variable study is divided into two parts for discussion catalyst parameters and reactor conditions. The catalyst is characterized by kg , X, and d7. Percent solubles is not considered because there is presently so little kinetic data to describe this. The reactor conditions chosen for study are those that have some significant effect on the kinetics temperature, pressure, and gas composition.

Mean Residence Time,T,hr. Base Case Yields Rate Constant 0.0524 cm/sec Lifetime, X=18.3 hr. Size dy= 0.0005 cm (+ks =0.01384) Temp., T=71°C Pressure P=261.8 psig Composition C3H0,Inerts. 76,. 24... 

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