Likewise, we can use regression analysis in excel to obtain the desired results. In addition, we can also see the regression equation in the chart area.Ĭlearly, we can infer from the chart that the weekly savings and income have a linear relationship. In this case, the above chart is an example of linear regression analysis in Excel with a least square regression line. So, if we plot a chart for regression analysis in Excel, we will get the result as shown in the image below: Now, we need to estimate the dependent variable based on the independent variable. Here, the Savings in $ is the dependent, response, or outcome variable, whereas the Income in $ is the independent, explanatory, or predictor variable.
In addition, regression analysis is quite useful in finance.įor example, consider the table below showing income and savings in columns A and B. Thus, we can numerically assess how the fluctuations in the independent variables affect the dependent variable. In simple terms, it evaluates the relationship between one dependent variable with one or more independent variables.Īlso, it helps determine the strength of the estimated relationship and defines the future relationship between the variables. Here the VLE curve crosses the 45° line indicating the mixture is an azeotrope and cannot be further separated by simple distillation alone.Regression Analysis in Excel is a group of statistical methods. Azeotropes have a composition at which both components have the same boiling point and therefore contacting the vapor and liquid phases will not cause phase changes of either component.įor example when setting up a VLE Curve for propanol and water we can see that something strange is happening at around x = 0.65. Some mixtures form an azeotrope or constant boiling mixture. Difficult separations require taller columns with more trays.įind out more in our article about relative volatility and activity coefficients. Separating two very similar components, for example ethane (C 2H 6) and ethylene (C 2H 4) is difficult. Separating two very different components, for example ethane (C 2H 6) and decane (C 10H 22) is easy. The difficulty of a separation is determined by the similarity of the two components. This results in rapid increase in the number of trays for ever smaller increases in purity. increasing the light fraction in the top product or decreasing the light fraction in the bottom product) drives us further and further into the narrow parts of the gap between VLE curve and the 45° line.
Note that this increase in efficiency doesn’t come for free, as in practice you will need a wider column to handle all of this liquid, as well as a larger reboiler to make enough vapour to send back through the liquid. With a higher reflux rate, the number of trays required decreases. Reflux rate has a significant impact on the performance of a distillation column. Step 2: Add 45 Degree lineĭraw a 45° line tuning from the origin to the top right corner, (0,0) to (1,1).Įffect of Varying the Parameters Reflux Rate On the y-axis is the mole fraction of the lighter component in the vapor phase. On the x-axis is mole fraction of the lighter component in the liquid phase. Target product quality (composition) of the top and bottom products.Dew point, boiling point and actual temperature of the feed (If the feed is sub-cooled or super-heated).Vapour-liquid equilibrium data for the feed components.In this section we describe the McCabe-Thiele method step by step, however prior to starting several pieces of information are required: In practice fluids do not reach equilibrium on each tray, and so the "tray efficiency" is used to determine the number of actual trays required to make a given separation. Trays calculated using the McCabe-Thiele method are called "theoretical trays". Other thermodynamics effects are negligible, e.g.The heat of vaporization of the two components are equal (When one mole of the heavier component is vaporised, one mole of the lighter component is condensed).The McCabe-Thiele method is a very simplistic model of distillation and subject to the following assumptions:
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