7.0RESULTTable 7.1: Vapor liquid equilibrium with constant volume of waterVolume of liquid, LTemperature outlet, CRefractive Index

WaterEthanolLiquidVaporLiquidVapor

3.00.189.486.41.337741.34137

3.01.087.584.31.333831.34167

3.02.082.576.81.333711.34239

3.03.078.674.71.333681.34175

Table 7.2: Vapor liquid equilibrium with constant volume of methanolVolume of liquid, LTemperature outlet , T1 CRefractive Index

WaterMethanolLiquidVaporLiquidVapor

0.53.073.867.11.342371.34169

1.03.074.569.51.342351.34165

2.03.075.372.11.341801.34191

3.03.079.774.41.341861.34229

Table 7.3: Mole fraction of water and methanol with constant volume of waterVolume of liquid, mlMole of mixtureMole fraction

WaterMethanolWaterMethanolWaterMethanol

3000100166.66672.4656680.9854220.014578

30001000166.666724.656680.8711260.128874

30002000166.666749.313360.7716760.228324

30003000166.666773.970040.6926070.307393

Table 7.4: Mole fraction of water and methanol with constant volume of methanol Volume of liquid, mlMole of mixtureMole fraction

WaterMethanolWaterMethanolWaterMethanol

500300027.7777873.970040.2730060.726994

1000300055.5555673.970040.4289160.571084

20003000111.111173.970040.6003370.399663

30003000166.666773.970040.6926070.307393

Mole fraction of methanolRI

Figure 7.1: Refractive index curve versus mole fraction of methanol

Table 7.5: Composition of methanol, X and Y of mole fraction Liquid (x)Vapor (y)

Temperature (0C)Temperature (K)Mole Fraction (x)Temperature (0C)Temperature (K)Mole Fraction (y)

89.4362.550.0512986.4359.550.07825

87.5360.350.0707984.3357.450.09784

82.5355.650.1146276.8349.950.21793

78.6351.750.1509874.7347.850.29434

73.8346.950.2915067.1340.250.68956

74.5347.650.3033969.5342.650.53326

75.3348.450.2671672.1345.250.41207

79.7352.850.1468174.4347.550.37092

Figure 7.2: T-x-y diagram of methanol-water mixture

Figure 7.3: x-y equilibrium diagram

8.0SAMPLE CALCULATION To calculate mole fraction of the mixture:Taken that from water and methanol properties:Density of water = 1 g/mlMolecular weight of water = 18 g/molDensity of methanol = 0.79 g/mlMolecular weight of methanol = 32.04 g/ mol

Number of mole = [Volume]i. Moles of Water, data taken from 3000 ml volume of waterNumber of moles = (3000 ml) = 166.6667 mol ii. Moles of Methanol, data taken from Number of moles= (100 ml) = 2.465668 moliii. Mole fraction of Methanol Mole fraction = = = 0.0145789.0DISCUSSIONVapor liquid equilibrium (VLE) data is an important uses for modeling separation processes on numerous stages of design, development and optimization of chemical plant (Kim, 2005). Specifically in oil and gas industry, it is used to develop and design the process for separation of hydrocarbon obtained to produce highly commercial product in our daily uses. In this experiment, the hydrocarbon involved is methanol and mixed with volume of water. This is purposely to study the binary mixture of ideal solution, where, mixture of two volatile liquid exhibit a range of boiling behavior from idea, with a simple continuous change in boiling point with composition, to non-ideal, showing the present of azeotrope and either a maximum or minimum boiling point.

From the result obtain as in Table 7.1, it is can be observed that as the volume of methanol was increased while volume of water is kept constant, the temperature of liquid and vapor are decreasing, whereas the refractive index, undergoes a slightly change in fluctuated pattern. This is because; the boiling point of methanol is lower than water which is 64.70C, Goodwin, (1987), as methanol was added increasingly, volume of mixture inside VLE was also increased, this will concentrated the volume of the mixture until both reach equilibrium. When the volume of mixture concentrated, the more molecules come closer together and eventually reach the critical point, where no difference between the liquid and gas phases (Taylor & Francis, 2009). Thus is will caused the mixture are faster to reach its boiling point which as the volume of methanol increase the lower boiling point of mixture, thus the temperature for vapor and liquid are decreasing.

From table 2, same principle applied, as the methanol is constant and the volume of water increased. The temperature for liquid and vapor are also increased, as the mixture was become diluted until both reach equilibrium. When the mixture diluted, less molecule closely came together, thus slowly to reach its boiling point. Hence, the temperature of liquid and vapor are increased. This is same went to refractive index as in Figure 7.1, RI as stated by Grigull et al, (1985), RI value of a medium is a measure of how much the speed of light is reduced in the medium (n = c/v), c, is speed of light and v, is medium. In this experiment as the temperature of mixture is boiled increasingly to its critical point the more liquid was produced, thus increasing value of v, as referred to the mole fraction of methanol, and decreasing value of n, which is the refractive index and this also applied to vapor.

There are two types of vaporliquid equilibrium diagrams are widely used to represent data for two-component (binary) systems. The first is a (T-x-y) diagram, where, x term represents the liquid composition in mole fraction and y term represents the vapor composition. From Figure 7.2, the lower curve is saturate liquid line, which gives the mole fraction of methanol in liquid phase x, The upper curve is the saturated vapor line, which gives the mole fraction of methanol in vapor phase y. From this figure also, it is can be noticed that the result are slightly deviated from the theoretical t-x-y diagram mixture of water and methanol. This deviation of resulted diagram is maybe caused by the digital display data of temperature from VLE equipment which hardly to achieve stable temperature, so it is difficult to record actual resulted temperature of liquid and vapor after reach equilibrium. Even though, the resulted diagram was deviated it is still showed slightly same pattern as theoretical diagram, as Figure 7.4.

Figure 7.4: Theoretical T-x-y diagram mixture of methanol-water

The second diagram in analysis of binary mixture is a plot of x versus y, where these types of diagrams are generated at a constant pressure. From Figure 7.3, it is showed slightly the same pattern of theoretical x-y diagram, Figure 7.5. The curved line in that Figure 7.3, represent the vapor composition of methanol that is in equilibrium with liquid x, the diagonal of the 45o line represent y = x. The deviation of the curved line from the diagonal line is therefore an indication of how wide the tie lines are, or the amount of separation that will takes place.

Figure 7.5: Theoretical x-y diagram mixture of methanol-waterRECOMMENDATIONFrom this experiment, few recommendations can be made: During recording that data of liquid and vapor temperature, wait until that temperature are stabilize to enhance the accuracy of final recorded data. Ensure that the temperature in a range of 50 C to 60 C before added another volume of methanol to avoid instantaneous vaporization as the methanol are a volatile hydrocarbon. Wear the glove, when handling the methanol throughout the experiment, as it is cool and irritating the skin Take cautious when pouring the methanol into VLE equipment, ensure our head are above the substance while pour it into, use ladder instead. As the methanol are hazardous, flammable, irritated, and volatile Ensure the all the mixture are drained after finish the experiment, to avoid deposited chemical in the equipment, that is, can disrupt the data for the next experiments conducted.

Younghun Kim, (2005). Vapor liquid equilibrium measurement for clean fuel processes. Chemical Engineering Report Series. Espoo 2005, No 48. Goodwin R.D., (1987). Methanol thermodynamic properties from 176 to 673K at pressure to 700 bar. Thermodynamic division, National Engineering Laboratory. Calorado. Taylor & Francis, (2009). Entropy and equilibrium. Chemical and Energy Process Engineer. Foxit Reader. Foxit Corporation, 2005-2010. Grigull et al, (1985). Refractive index of water and its dependence on wavelength and density. [thesis]. Themodynamic. Technical University Munchen. 21-D8000. Federal republic of German