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PLATE AND FRAME FILTER PRESS

1.0 OBJECTIVES

From this experiment, the objectives is to study the operation of filter press for

filtration by using calcium carbonate slurry. By the data obtained from this experiment, it can

be determined the filter medium resistancce and specific cake resistance from the filtration.

2.0 SUMMARY

In this experiment, the operation of filter press for filtration of calcium carbonate

slurry was determined. On the other hand, the filter medium resistance and specific cake

resistance from filtration data was obtained by the end of the experiment. The experiment was

achieved by following the manual instructions whereas the 5% of mixture between calcium

carbonate and water which become the slurry. On the other hand, the pressure drop used to

get the volume of filtrate is 30 psi. The sample of filtrate was taken at the different time

intervals. The results for weight and dry cake was collected for different tray and the

different of total of the weight is to be 0.8 kg. The time taken for the slurry to finished up

inside the slurry tank was taken. The results shows that the time taken for 100 L of slurry to

finished is 22.46 minutes. Based on the tabulated result, the data for viscosity and density for

three trays of average differences filtrate collected at 20, 50 and 100 L. The differences in

viscosity and density of the different samples was affected by resistance in the tray.

Futhermore, the graph time per volume (s/L) vs filtrate volume has been plotted in order to

analysed the t/V with the filtrate volume and obtaining the straight line of graph. Moreover,

the average of resistance of filter medium resistance is 9.72x10^12 cm2/s while the average

resistance for filter cake resistance is 2.93x10^11 cm4/kg. In a nutshell, the efficiency of the

filtration process is determined by the filter medium resistance and also specific cake

resistance in filter press unit.

MASS TRANSFER 2 Page 1


3.0 RESULTS

1. Weight fraction of calcium carbonate in slurry: 5.00 %

A. Weight of wet cake

Table 1.0 Weight of wet cake

Tray 1 : 4360 g

Tray 2 : 290 g

Tray 3 : 200 g

Total : 4850 g

B. Weight of dry cake

Table 1.1 The weight of dry cake

Tray 1 : 3910 g

Tray 2 : 120 g

Tray 3 : 50 g

Total : 4080 g

i. Weight ratio of wet cake to dry cake (mF/mC): 1.189 g

ii. Density of calcium carbonate: 2.93 g/cm3

iii. Total active filter area: 47 cm x 470 cm = 22090 cm2

iv. Pressure drop (CP): 30 psi

v. Total filtration time: 1347.6 s

vi. Total volume of filtrate: 100 litre



Filtrate volume, V(litre, L)

Time, t(s)

t/V(s/L)

0 0 -

5 59 11.8

10 241.8 24.18

15 301.8 20.12

20 361.2 18.06

25 422.4 16.90

30 481.8 16.06

35 546.6 15.62

40 608.4 15.21

45 670.2 14.89

50 731.4 14.63

55 793.8 14.43

60 853.8 14.23

65 915.6 14.09

70 975 13.93

75 1036.2 13.82

80 1099.2 13.74

85 1161.6 13.67

90 1224 13.60

95 1286.4 13.54

100 1347.6 13.48

Table 1.2: Filtrate volume and Time Data



Figure 1.0: Graph of t/V versus V

Table 1.3: Viscosity and Density of Filtrate at 5L, 40L and & 75L

Volume 20 L 50 L 100 L

Viscosity, µ (Pa.s) 0.001 0.0008 0.0008

Density, ρ (g/cm3) 0.9972 0.9971 0.9971

Table 1.4: Filter medium resistance for three trays and average resistance

Rm1(20 L) Rm2 (50 L) Rm3(100 L) Average Rm

8.36 x10^12 cm2/s 1.04x10^13 cm2/s 1.04x10^13 cm2/s 9.72x10^12 cm2/s

Table 1.5: Filter cake resistance for three trays and average resistance

α1 (20 L) α2 (50 L) α3 (100 L) Average α

7.04 x 10^11 cm4/kg 8.80x10^10cm4/kg 8.80x10^10 cm4/kg 2.93x10^11 cm4/kg


t/V versus V


4.0 DISCUSSION

In this experiment, the operation of filter press for filtration of calcium carbonate

slurry and filter medium resistance and specific cake resistance from filtration was obtained.

Basically, filtration is the removal of solid particles from a fluid by passing the fluid thrugh a

filtering medium on which the solid are deposited. Theoritically, filter press is a separation

process whereby employed by solid and liquid separation or known as slurry using the

principle of pressure drive. The pressure drive provided by a slurry pump. Filter press is a

fixed volume and batch operation. In this experiment, a liquid–solid filtration is carried out

which is often called “cake–filtration”.

The experiment was start up by dissolving 5 kg of calcium carbonate into a 100 litres

of water in the slurry tank. The mix of water and calcium carbonate known as slurry. The

slurry was let to be stirred in the tank for several minutes. After that, the filtration process was

done by starting up the pump and the slurry flowing through the filtering medium. The result

was collected and tabulated by taking its time for every 5 L for the filtration yield to

discharged from the filter press machine. The process continously ran until the slurry in the

tank is finished.

Based on table 1.2, the result obtained show that the the t/V is highest at the 10 L

which is at the 24.18 s/L. As the time increases, the t/v was decreasing over time. Basically,

the filter cakes are accumulated in each of the hollow frame. As the filter medium becoming

thicker due to the slurry stucked by, the resistance was also increased. Hence, the increasing

resistance will affecting the t/V to become highest. On the other hand, the plotted graph shows

that the t/V decreasing over time since as time volume increasing, the filter cake resistance is

increasing since the the calcium carbonate in the slurry are retained on the surface of the

medium where they build up, forming an increasing thicker cake. However, the fluctuation of

the graph at 5 L to 10 L is due to the mechanical problem. The pump was suddenly stop after

5 L reading hence the time taken for the next 10 L was increasing since the pressure drive of

slurry to the filter medium is zero.



For the cake filtration, the effeciency of the filtering medium was being obtained and

analysed. Based on the result, it can be seen that the highest weight of wet cake is at the first

tray of the filter medium. The weight obtained is 4.36 kg while for the second and third tray is

0.29 kg and 0.20 kg respectively. This result shows that the effeciency of filtration is

decreasing as passing the tray. On the other hand, Table 1.3 shows a results of the viscosity

and density of filtrate at 20, 50 and 100 L. The result obtained shows that the the highest

viscosity and density is at the first 20 L. This is due to the filter cake build up at the tray

affecting the viscosity and density. Theoritically, viscosity is measure of how the fluid flows

or the ‘thickness’ of the fluid while density is a degree of compactness of the substances. As

the slurry passing by the filter more cake resistance were build up at the tray and become

resistance hence make just a fewer particle succeed to tresspassing the filter. This situation

make the viscosity and density at 50 L and 100 L are decreasing.

Table 1.4 shows the filter medium resistance for three trays and average resistance

while table 1.5 shows the filter cake resistance for three trays and average resistance. The

higher resistance shows at the 20 L which is 8.36 x10^12 cm2/s compared to the 100 L which is

9.72x10^12 cm2/s. On the other hand, the filter cake resistance shows that the higher number is

at 20 L which is 7.04 x 10^11 cm4/kg. In addition, the amount of the filtrate should be same as

the feed. Basically, the filtrate which is in the dry cake should be same as the feed which is 5

kg of calcium carbonate. Based on result, the dry cake obtained is 4.08 kg from 4.85 kg of wet

cake after the drying process. This is due to the filtration of the calcium carbonate was not

100% fully achieved. Futhermore, a straight line which connecting all of the points will

determined the 100% effeciency of the filtration process. Some of the erros might be due to

the error during running the experiment such as the failure of the pump and also the deposit

and blocking of the calcium carbonate in the experiment.



5.0 CONCLUSION

Based on the experiment, it can be concluded that the filter press instrument filtering a

solid particles from a fluid by using a filtering medium on which solid are deposited. As the

more deposited cake on the filtering medium, the higher the resistance was. Futhermore, the

average filter medium resistance and specific cake resistance had been determined by

referring to the graph. On the other hand, the weight of wet and dry cake has been determined

where it shows the percentage of the filtration process. Moreover, the pressure drop, filter

medium and also the size of particles affecting the average filter medium resistance and

specific cake resistance.

The recommendation for the experiment in order to get the accurate result is by

monitoring the pump so it would not be stop a certain time thus affecting the time taken for

each volume. Other than that, the mixture of the calcium carbonate and water or sluury should

be mixed well before going through the filtration process. Futhermore, as the reading of

viscosity are too slightly different, hece the test by using viscosity meter should use the

medium spindle and the speed should be less than 50 mm/s in order to get the accurate

reading. As a conclusion, the objectives of this experiment in order to study on how filtration

works on the operation of filter press for filtration calcium carbonate slurry and its filter

medium resistance and specific cake resistance was succesfully achieved.



6.0 APPENDIX

APPENDIX

Graph and Calculation

1. Plot the data relating versus V to obtain a straight line graph.

2. The slope of each line is in seconds per litre and from the intercept of the line.

Linear equation

t/V = (Kc / 2)V + 1/qo

y = - 0.0569 + 18.287

-Find Kc

Because m = , so unit for =



x , Kc = 28450

Find qo

= y-intercept

qo = 0.0547 x

qo = 5.468 x

3. Find the value of filter medium resistance (Rm) and cake resistance (α) from the equation:

Table 7: Viscosity of filtrate (μ)

At V= 20 L : 0.001 Pa.s

At V= 50 L : 0.0008 Pa.s

At V= 100 L: 0.0008 Pa.s

Pressure drop = 30 psi × [(1.01325 × 105Pa) / 14.696psi] = 206841.998 Pa

=

A = 22090 cm2 = 2.209 m 2



=

= 8.36× 10 12 m -1

Table 5: Calculated filter medium resistance for three trays.

Rm1(20 L) Rm2 (50 L) Rm3(100 L)8.36 x10^12 cm2/s 1.04x10^13 cm2/s 1.04x10^13 cm2/s

Rm = Rm1 + Rm2 + Rm3

= 9.72x10^12 cm2/s

4. Finding the value of cake resistance ( ) using value (µ) from table 7:

=

c =

=

= x

= 40.8



=

=

= 7.04 × 10 11 m/kg

Table 6: Calculated filter cake resistance for three trays.

α1 (20L) α2 (50L) α3 (100L)

7.04 x 10^11 cm4/kg 8.80x10^10cm4/kg 8.80x10^10 cm4/kg

=

= 2.93x10^ 11 cm 4 /k



7.0 REFERENCES

1. Plate and Frame Filter Press Construction and Working Theory

Retrieved from: http://www.leofilterpress.com/filter_press/?555.html

2. Trebal, R. E. (1980). Chemical Engineering Series: Mass Transfer Operation. 3rd

Edition International Editions in Related Fields: Mcgraw-Hill.

3. Filter Press Operation

Retrieved from: http://www.industry

animated.org/teachers%20notes/filter_press_pdf.pdf


http://www.leofilterpress.com/filter_press/?555.html

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