CALCULATIONS
At Pressure = 1.5 cm of water
Weight of dry solid, S = 100 gm
Amount of initial moisture = 15 ml
Weight of solid, W= solid + water
Moisture content present in solid,
We have the experimental data as :
Time ,t
(sec)

Wt. of solid(solid + water ) W
(gm)

Moisture content present in solid X
(gm water/gm of dry soild)

0 
115

0.15

3 
112

0.12

6 
109

0.09

9 
107

0.07

12 
105

0.05

15 
103

0.03

18 
101

0.01

21 
100

0

Now we plot a X vs t plot as shown
.
From this plot we calculate the slope = dx/dt.
Now we have the drying rate as
For a constant area we hve the drying rate equation as :
Thus we have the table as :
Time,t
(sec)

Wt. of solid
(solid + water ) W
(gm)

Moisture content present in solid X
(gm water/gm of dry soild)

Slope
= dx/dt

N(Area const)
gm/sec

0 
115

0.15

0.0102

1.02

3 
112

0.12

0.009324

0.9324

6 
109

0.09

0.008448

0.8448

9 
107

0.07

0.007572

0.7572

12 
105

0.05

0.006696

0.6696

15 
103

0.03

0.00582

0.582

18 
101

0.01

0.004944

0.4944

Finally we plot a graph between X vs N as shown :
The same steps are repeated for other runs at different operating conditions.
COST CALCULATIONS:
Total time of drying = 21 min
Therefore No. of batches processed in a day = 24*60/21 = 68.57
Amount dried in one batch = 100 Kg
Therefore total weight = (100*68.57)Kg
Let us consider an orificemeter with the following diameters:
Diameter of the pipe , d_{1} = 0.039 m
Diameter of the orifice hole , d_{2} = 0.052 m
Coeffecient of discharge , C_{d} = 0.6
Therefore the areas are :
Area of the pipe , A_{1} =( 3.14*(0.039)^{2})/4 = 0.00119 m^{2}
Area of the orifice hole , A_{2} = ( 3.14*(0.052)^{2})/4 = 0.00212 m^{2 }
Now we have the volumetric flow rate as :
Where H is
= 1.5*((1000/1.2)1)/100 m
=12.485 m
Therefore the volumetric flow rate = 0.013554 m^3/s
The mass flow rate G :
G = Q * Density of air
= 0.013554 * 1.2
= 0.016265 Kg/sec
We have the specific heat of air C_{p}= 1.005 kJ/kgK
Temperature at which drying takes place = 340 K
Therfore amount of heat removed Q_{1}
=0.016265 *1.005 * (340298)
= 0.683472 KW
= 3515.001 KWH(taking effeciency as 0.7)
Let us assume thre industrial rate to be Rs 10 per unit
Therfore cost = 35150.01Rs
Cost per unit weight = 5.12Rs/Kg.