CPB 20104 Mass Transfer 2 UniKL MICET Experiment 3: Plate and Frame Filter Press full lab report

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1.0 OBJECTIVES The objectives of this experiment are to study the operation of filter press for filtration of calcium carbonate slurry and to determine filter medium resistance and specific cake resistance from the filtration data obtained from the experiment. 2.0 SUMMARY / ABSTRACT The objective for this experiment is to study the operation of plate and frame filter press and determine the filter medium resistance and specific cake resistance from the filtration data obtained. Filter press is a separation process to separate liquid and solid mixture, or in this experiment, slurry liquid. To get a slurry liquid, calcium carbonate weight 3kg were mixed with water, and stirred till it gets slurry. The mixture was then poured into a reactor to be stirred for a few min before experiment starts. Once the machine starts, the time was recorded for every 5L of filtrate produced. The filtrate is thrown away but filtrate of 5L, 50L and 100 L were kept to determine its viscosities and densities using viscometer. Next, the cake produced at each frame and filter press were collected and weigh before dried for one whole day. The cake need to be weigh the next day, after it is fully dried. The viscocity and density for each volume are 0.80 Pa.s for 5L,1.12 Pa.s for 50L, and 1.21 Pa.s. For the density 1.0067 g/cm3 for 5L,1.0146 g/cm3 for 50L, and for 100L is 1.012 g/cm3respectively. This means that the fedd were properly stirred before it enters the frame and filter press. The value for filter medium resistance and cake resistance are 0.3764 x 106 for 5L,0.2583 x 106 for 50 L, 0.2411 x 106 for 100L.For cake resistance 0.731 x 106 for 5L,3.118 x 106 for 50L, and 2.93 x 106 respectively.

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3.0 RESULT / DATA

Table 1 Weight position of calcium carbonate in 3 % slurry Weight wet cake

Tray 1 :100 g Tray 2 :180 g Tray 3 : 290 g

Weight dry cake

Tray 1 :70 g Tray 2 :130 g Tray 3 : 240 g

Weight ratio wet cake to dry cake

Tray 1 :1.43

(ms/mc)

Tray 2 :1.38 Tray 3 :1.21

Viscosity of filtrate (μ)

Tray 1 :0.80 Pa.s Tray 2 :1.12 Pa.s Tray 3 :1.20 Pa.s

Density of filtrate (ρ)

Tray 1 :1.0067 g/cm3 Tray 2 :1.0146 g/cm3 Tray 3 :1.012 g/cm3

Density calcium carbonate (ρ)

2.93 g/cm3

Total active filter area

47 cm x 470 cm

Pressure drop

10psi

Total filtration time

1047 seconds

Total volume filtrate

100L

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FILTARE VOLUME,V(L)

TIME, (s)

TIME/VOLUME, (s/V)

0

0

0

5

0.49

0.098

10

88.8

8.88

15

144

9.6

20

201.6

10.08

25

255.6

10.224

30

309.6

10.32

35

366

10.46

40

421.8

10.55

45

452.4

10.05

50

510

10.2

55

562.8

10.23

60

624

10.4

65

679.2

10.45

70

734.4

10.49

75

796.2

10.62

80

853.8

10.67

85

909

10.69

90

964.8

10.72

95

995.4

10.48

100

1047

10.47

Table 2

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Figure 1 (t/V) versus filtrate volume (V)

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From graph Y = 0.0588x +6.3761 Formula for medium resistance (Rm) Rm = A(ΔP) q0(μ) For tray 1 Rm = (0.658m2)(68947Pa) (6.3761)(0.8Pa.s) = 0.3764 x 106 For tray 2 Rm = (0.658m2)(68947Pa) (6.3761)(1.12Pa.s) = 0.2583 x 106 For tray 3 Rm = (0.658m2)(68947Pa) (6.3761)(1.20Pa.s) = 0.2411 x 106 Table 3 Medium resistance (Rm ) of each tray Tray 1 Medium resistance (Rm)

0.3764 x 106

Tray 2 0.2583 x 106

Tray 3 0.2411 x 106

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Formula for cake resistance (α) α = KC(A2)(ΔP) μ(c) For tray 1 α = (0.1176)(0.0658m2)(68947Pa) (0.80)(6 x 10-3) = 0.731 x 106 For tray 2 α = (0.1176)(0.0658m2)(68947Pa) (1.12)(1 x 10-3) = 3.118 x 106 For tray 3 α = (0.1176)(0.0658m2)(68947Pa) (1.20)(1 x 10-3) = 2.93 x 106 Table 4 Cake resistance (α ) of each tray

Cake resistance (α)

Tray 1

Tray 2

Tray 3

0.731 x 106

3.118 x 106

2.93 x 106

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4.0 DISCUSSION According to McCabe et al., filter press is a discontinuous pressure filter contains a set of plates designed to provide a series of chambers or compartments in which solids may collect. The filter presses operate under pressure using the process of cake filtration. This experiment has been conducted using this equipment and preparations are made in order to conduct the experiment. The main objective is to determine the operational of the filtration of calcium carbonate slurry. The weight of fraction calcium carbonate in slurry is about 3 wt%. This involves sending slurry through the press, which is equipped with filter cloths. The cloths pick up the particles in the slurry and allow the solvent (water) to pass through. As more slurry moves through the press, the cake builds up and assists the filtration process (Ng Peng Sang, 2009). The filtrate samples were taken at differences volume and time recorded (5 liters, 50 liters and 100 liters). Then, the sample had undergone the viscosity and density tests which is resulted as in Table 1 and Table 2. From the result, the average viscosities (μ) of the filtrates are about 1.04 Pa.s and the density (ρ) is averagely 1.0111 g/cm3. The result shown that the filtrate liquids are contains no or too little of the solids amount, which is remain at the filter media as filtered cake because the calcium carbonate is suspended solid in the mixture. Table 1 shows the values of the different density and viscosity of the different volume which are V=5L, V=50L and V=100L. The relation of the density and viscosity of the filtrate is proportional. For the first 5L, the value was the highest because of the cake and filter medium resistance was at in initial stage, which is the lowest. This is also caused by the pressure is at its highest since there was still less resistance in during the first 5L. Then, at V=50L the value of density and viscosity decreases compared to value of the first 5L. This is because the cake resistance was starting to build up and less particle can get through as the filter filtrate more calcium carbonate compared to the first 5L. At the final volume, V=100L, the viscosity had remained constant because of the cake resistance had remained constant. The density still decrease, this may not be correct as it is also have to remain constant as density V=50L. This may be caused by experimental error where air is trapped inside the density meter which cause density

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value is less than it is supposed to be. The weight of cake both dry cake and wet cake was different for every tray. The Tray 1 has the lowest weight wet cake which is 100g but Tray 1 should be the highest weight wet cake because it is the first tray that was in contact with the filtrate. The cake has to build up at Tray 1 that causes it to have the highest weight. The third tray has higher weight which is 290g compare to Tray 2 which is 180g because of Tray 3 has smaller holes for its filter than Tray2. The different of weight of wet cake and dry cake is because of the weight of moisture (water) content in wet cake. With some filter cakes, the specific resistance varies with the pressure drop across. This is because the cake becomes denser under the higher pressure and so provides fewer and smaller passages for flow due to compressibility of the cake. The pressure drop of this experiment was constant at 10 psi. Filter cake build up on the upstream side of the cloth which is the side away from the plate. In the early stages of the filtration cycle, the pressure drop across the cloth is small and filtrations proceeds at more or less a constant rate. As the cake increase, the process becomes more constant-pressure. Calcium carbonate is directly affected by the pressure drop because of the size of its particle. A plot of Time/Volume of filtrate (in s/L) versus Volume of filtrate (in L) should give a straight line with a slope of Kc/2, which will allow the calculation of the specific cake resistance, α. Also, the intercept will be 1/q0, which will allow the calculation of filter medium resistance, Rm. As refer to the Figure 1 the t/V increase at initial 5L and constant until 100L over the volume of filtrate fluid, which give the slope of constant in equation for half of constant rate filtration value (Kc/2) is 0.0588 s/litre2 and intercept of one over volumetric flow rate at start of filtration (1/q0) at 6.3761 s/litre. This phenomenon occurred because of the slurry concentration is too thin which calcium carbonate weight fraction in slurry about 3 wt% that given rapid filtration time of the slurry through the filter medium. As in the Table 1, since the viscosity of the filtrate for Tray 1, Tray 2 and Tray 3 are 0.8 Pa.s, 1.12 Pa.s and 1.20 Pa.s, respectively. The calculation of filter medium resistance, Rm for Tray 1, Tray 2 and Tray 3 are 0.3764 x 106, 0.2583 x 106 and 0.2411 x 106, respectively as in Table 3 and the calculation of the specific cake resistance, α for Tray 1, Tray 2 and Tray 3 are 0.731 x 106, 3.118 x 106 and 2.93 x 106, respectively as in

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Table 4. From the graph, at t=0.49 second, the t/V is 0.098 s/L at the first 5L but it should be the highest because there were less cake resistance during the first 5 liters as the cake resistance had just started to build up. A filter cake is formed by the substances that are retained on a filter. The filter cake grows in the course of filtration, becomes thicker as particulate matter is being retained. With increasing layer thickness the flow resistance of the filter cake increases. From V=5L until V=50L the resistance of the filter cake resistance was starting to increase, that causes the graph to descend. As time volume increase, the filter cake resistance is increasing until the cake was fully stuffed at the trays. From V=70L to V=100L the graph become linear, this proof that the cake resistance is at its maximum and cannot build up anymore. The filter medium resistance changed only when the pressure drop changed. Cake resistance is based on the volume of filtrate stuck in the filter.

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5.0 CONCLUSIONS & RECOMMENDATIONS Filter press is a discontinuous pressure filter contains a set of plates designed to provide a series of chambers or compartments in which solids may collect. The filter presses operate under pressure using the process of cake filtration. The filtrate samples were taken at differences volume and time recorded (5 litres, 50 litres and 100 litres). Then, the sample had undergone the viscosity and density tests. The result shown that the filtrate liquids are contains no or too little of the solids amount, which is remain at the filter media as filtered cake because the calcium carbonate is suspended solid in the mixture. The relation of the density and viscosity of the filtrate is proportional. For the first 5L, the value was the highest because of the cake and filter medium resistance was at in initial stage, which is the lowest. This is also caused by the pressure is at its highest since there was still less resistance in during the first 5L. Then, at V=50L the value of density and viscosity decreases compared to value of the first 5L. This is because the cake resistance was starting to build up and less particle can get through as the filter filtrate more calcium carbonate compared to the first 5L. At the final volume, V=100L, the viscosity had remained constant because of the cake resistance had remained constant. The density still decrease, this may not be correct as it is also have to remain constant as density V=50L. This may be caused by experimental error where air is trapped inside the density meter which cause density value is less than it is supposed to be. The problem occurred throughout the experiment is the filter that was used was old, so the filtration process can’t be done correctly. Besides that, the surface of the plate shifters is too rough to move. These are the solution for the problems. The equipment delivered and placed in storage shall be stored with protection from the weather, excessive humidity and temperature variations, dirt, dust or other contaminants as required by the manufacturer. An adequate means of lubrication shall be provided for moving parts subject to wear. Except as otherwise specified, lubrication shall be by grease or oil to move the plates, allowing the rapid discharge of the solids stuck in between them.

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6.0 REFERENCES 1. Transport Processes & Separation Process Principles, Christie John Geankoplis, Pearson Education Limited (Fourth Edition), 2014. 2. Plate and Frame Filter Press, Ranesh Kumar, Handbook of Nonwoven Filter Media, 1992. 3. https://en.wikipedia.org/wiki/Filter_press

7.0 APPENDICES From graph Y = 0.0588x +6.3761 Formula for medium resistance (Rm) Rm = A(ΔP) q0(μ)

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For tray 1 Rm = (0.658m2)(68947Pa) (6.3761)(0.8Pa.s) = 0.3764 x 106 For tray 2 Rm = (0.658m2)(68947Pa) (6.3761)(1.12Pa.s) = 0.2583 x 106 For tray 3 Rm = (0.658m2)(68947Pa) (6.3761)(1.20Pa.s) = 0.2411 x 106 Table 3 Medium resistance (Rm ) of each tray Tray 1 Medium resistance (Rm)

0.3764 x 106

Tray 2 0.2583 x 106

Tray 3 0.2411 x 106

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Formula for cake resistance (α) α = KC(A2)(ΔP) μ(c) For tray 1 α = (0.1176)(0.0658m2)(68947Pa) (0.80)(6 x 10-3) = 0.731 x 106 For tray 2 α = (0.1176)(0.0658m2)(68947Pa) (1.12)(1 x 10-3) = 3.118 x 106 For tray 3 α = (0.1176)(0.0658m2)(68947Pa) (1.20)(1 x 10-3) = 2.93 x 106 Table 4 Cake resistance (α ) of each tray

Cake resistance (α)

Tray 1

Tray 2

Tray 3

0.731 x 106

3.118 x 106

2.93 x 106