#HOW TO USE DEPRIESTER CHART TO FIND TEMPERATURE MANUAL#
In table 7, the result generated by the program is same as that of the manual in the obtained dew point temperature, but differs in the other obtained variables. Design the program algorithm, convert to MATLAB statements State the problem statement of the design N Σ i=1 = R min + 1 (7)įor the column’s variables obtained, the following steps were followed: Ө will lie between α LK and α HK, that is α LK˃Ө ˃ α HK ī) Obtain the minimum reflux ratio using equation (7) below: Design the minimum reflux ratio at condition of minimum reflux, using the two Underwood’s model equations:Ī) Obtain the reflux factor using equation below: Test for α av accuracy in estimation using Douglas’s inequality below: Obtain the relative volatilities of the components at the dew-point and bubble-point temperatures and determine the average: Calculate the bubble-point temperature, solving iteratively: The K-values were obtained from the vapour-liquid equilibrium data for hydrocarbons (Depriester chart) in. The temperature is obtained by solving the above equation iteratively. Determine the required design specifications For multi-component distillations with non-adjacent key components, the Underwood equations are difficult to solve, as multiple reflux factors exist but only one of the factor is required. For multi-component distillations with only two adjacent distributing components, the Underwood equations can still be solved as binary component calculations and accurate results can be achieved. The value of the thermal condition of the feed q, according to depends on the nature of the feed as follows:įor a binary distillation, the Underwood equations can be easily solved using the two steps listed above, since the two components in the mixture are already taken as the light and heavy key components and there is only one factor lying between the volatilities of such components. The Underwood method first solves an equation which relates to feed composition x f, thermal condition of the feed q, and relative volatility α in order to determine a factor Ө, which lies numerically between the relative volatilities of the two key components. Constant relative volatility throughout the whole column. Constant vapour and liquid molar overflow in the rectifying section and in the stripping section of a column. The Underwood method makes the following assumptions : In this section, only some important features of the Underwood method are addressed. Under the minimum reflux condition, Underwood developed sets of equations to calculate the minimum vapour flow rate. It assumes a constant relative volatility for each component throughout the column. It is impractical for useful operation, but they are valuable guidelines within which the practical distillation must be designed. It gives fast convergence of design solutions. The Underwood’s model serves as a good initializing design model for determining the minimum reflux for more complex distillation columns. Matlab is a fourth generation computer programming tool with highly interactive features making it user-friendly to its human users and other computer programming languages such as Java ®, FORTRAN, C/C++ and giving faster solutions to iterative and design problems. It integrates modern computation, visualization, and programming environment: it has sophisticated data structures, contains built-in editing and debugging tools, and supports object-oriented programming making it an excellent tool for teaching and research. Matlab is a high performance language for technical computing. This work will help to show proof that developing a good computer design skill is very efficient, time-saving and is now an essential 21st-generation skill to acquire to fully specialize as a process design expert, as compared to depending on the cumbersome manual design approach as still practiced in many Nigerian universities. Many chemical engineers do not want to specialize in designing columns because of how hectic, boring and time wasting their calculations can be. To analyze the results obtained from the manual and computer shortcut design methods. To obtain a computer based design and optimization of the Underwood’s shortcut model. To obtain initial reflux ratio manual design estimate for a plate distillation column, using Underwood’s shortcut model. Minimum reflux is an extreme operating condition for a distillation column, and can be approximated by Underwood’s method to obtain the minimum and optimum reflux ratio of the column for its optimization.