Distillation is the most widely used separation process in the chemical industries. The separation of mixtures by distillation depends on the relative volatilities between the components. The greater the relative volatilities, the easier the separation.
DME can be used as an alternative raw material when it is converted to gasoline. The DME is converted to gasoline range hydrocarbons over a zeolite catalyst. In the gasoline production reaction, some reactions cause unwanted components which may be regarded as impurities. These include carbon monoxide, carbon dioxide and light olefins.
Gasoline with less impurities is regarded as of greater quality and sells at a higher price. A distillation column can be used to separate the desired hydrocarbons …show more content…
The desired fraction of the heavy key and light key in the bottoms and distillate respectively is at least 99%. The relative volatility of the components is calculated at the initial temperature using Equation 2. lnα_(LK-HK)= (P_LK^*)/(P_HK^* ) (2)
The vapour pressure values were obtained from Aspen and can be found in Appendix A. The relative volatility is 4.06 and found is Nmin is 6.56.
To calculate the minimum feed stage Equation 3 is used. N_(F,min)=(l n([x_LK/x_Hk ]_dist/[z_LK/z_Hk ]))/(lnα_(LK-HK) ) (3)
This yields NF,min = 2.26
Underwood equations
The underwood equations estimate the minimum reflux ratio of the distillation column. The following steps are followed in estimating the minimum reflux
DME can be used as an alternative raw material when it is converted to gasoline. The DME is converted to gasoline range hydrocarbons over a zeolite catalyst. In the gasoline production reaction, some reactions cause unwanted components which may be regarded as impurities. These include carbon monoxide, carbon dioxide and light olefins.
Gasoline with less impurities is regarded as of greater quality and sells at a higher price. A distillation column can be used to separate the desired hydrocarbons …show more content…
The desired fraction of the heavy key and light key in the bottoms and distillate respectively is at least 99%. The relative volatility of the components is calculated at the initial temperature using Equation 2. lnα_(LK-HK)= (P_LK^*)/(P_HK^* ) (2)
The vapour pressure values were obtained from Aspen and can be found in Appendix A. The relative volatility is 4.06 and found is Nmin is 6.56.
To calculate the minimum feed stage Equation 3 is used. N_(F,min)=(l n([x_LK/x_Hk ]_dist/[z_LK/z_Hk ]))/(lnα_(LK-HK) ) (3)
This yields NF,min = 2.26
Underwood equations
The underwood equations estimate the minimum reflux ratio of the distillation column. The following steps are followed in estimating the minimum reflux