florida institute of technologymy.fit.edu/~akurdi2012/process lab 2/drying/drying report.pdf · in...

Florida Institute of Technology College of Engineering

Department of Chemical Engineering

CHE – 4115

ChE Process Laboratory II

Short Report # 1

Experiment # 1

Drying Experiment

Performed by: Abdullah Kurdi

For: Dr. Maria Pozo de Fernandez

Experiment performed on: February 9, 2016

Date: February 23, 2016

Team D Grade:

Partners: H. Baatiyyah

N. Almakhmari

K. Almansoori

F. Alkhaldi

1

I. Introduction

In the Materials Laboratory, an experiment dealing with catalysis was conducted

using dry air to prevent corrosion that is caused by the moisture in the inlet air stream. A

column of Indicating Drierite was used to dry the inlet air stream. The concern in this

experiment was that the amount of Indicating Drierite could be insufficient. This drying

experiment was then conducted to investigate how much water can be absorbed to the

Indicating Drierite and what time and temperature removes water successfully from the

Indicating Drierite such that it can be used again.

II. Materials and Instrumentation

1. 10 grams of Indicating Drierite.

2. 20 ml of DI Water.

3. Drying oven

4. Metal dish

5. Dish Holder

6. Weight Scale

7. Oven Gloves

8. Scapula

9. Stopwatch

Figure 1: Diagram of the Apparatus

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III. Procedure

1) Prepare 10 g of Indicating Drierite in the metal dish, and find the total weigh it.

2) Add 4 ml of DI water to the sample and weigh it.

3) Preheat the drying oven to 275 oC.

4) When the desired temperature is reached, place the metal dish inside the oven and

start the stopwatch.

5) After each minute, record the temperature and then bring the metal dish outside

the oven and weigh it and then return it back into the oven.

6) Continue to measure the weight, time, and temperature until the weight of the

sample reaches its original weight, or less.

7) Repeat the procedure for 250 oC, 225

oC, 200

oC, 175

oC.

3

IV. Experimental Results

Trial #1

Starting Temperature is 275 oC

Waiting Time is 60 sec

Drierite Weight is 10 g

Water Volume is 4 ml

Total Weight is 13.91 g

Table 1: Time, Wight, and Temperature for the trial starting temperature of 275 oC

Time (sec) Total Weight (g) Temperature (oC)

0 13.91 275

60 13.12 266

120 12.16 256

180 11.53 255

240 11.08 251

300 10.73 248

360 10.48 242

420 10.3 238

480 10.13 236

540 10.05 233

600 9.96 231

4

Trial #2



Drierite Weight is 9.94 g





0 13.73 251

60 13.06 245

120 13.02 237

180 11.34 232

240 10.88 227

300 10.51 221

360 10.15 219

420 10.08 215

480 9.96 210

540 9.89 205

5

Trial #3








0 13.49 226

60 13.03 222

120 12.18 218

180 11.50 215

240 11.02 213

300 10.65 209

360 10.34 208

420 10.12 207

480 10.00 206

540 9.89 204

6

Trial #4








0 13.81 202

60 13.14 198

120 12.31 196

180 11.58 194

240 11.14 192

300 10.73 193

360 10.41 194

420 10.18 195

480 10.01 196

540 9.89 197

7

Trial #5








0 13.99 174

60 13.7 173

120 13.16 173

180 12.51 174

240 11.86 174

300 11.24 174

360 10.8 173

420 10.49 174

480 10.24 174

540 10.04 173

600 9.95 173

660 9.84 173

Table 6: Average Temperature, Final Time, and Heat Transferred for each temperature Trail

Temperature Trail (oC) Average Temperature (

oC) Final Time (sec) Heat Transferred (KJ)

275 248.3 600 11.46

250 226.2 540 11.29

225 212.8 540 11.18

200 195.7 540 11.05

175 173.5 600 10.87

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Table 7: Amount of Water Adsorbed and Desorbed from the Sample for each Temperature Trial

Average Temperature (oC) Water Absorbed (g) Water Desorbed (g)

248.3 3.91 3.95

226.2 3.79 3.84

212.8 3.57 3.60

195.7 3.90 3.92

173.5 4.09 4.15

Total 19.26 19.46

Figure 2: Mass versus Time for each temperature trail

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Figure 3: Change in mass versus Time for each temperature trail

Figure 4: Time of final mass versus Average Temperature of each temperature trail

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Figure 5: Time and Heat Transferred vs. Temperature

V. Discussion

Indicating Drierite is a compound that is used as an indicator of dryness. It

consists of calcium sulfate that is saturated with cobalt chloride; it has a blue color when

it is dry and turns into pink when exposed to moisture (1)

.

From the data collected, it can be noticed that the mass of the sample decreases as

it spends more time in the drying oven. Figure 2, shows the mass of the sample with

respect to time for each temperature trial; the graph decreases with time due to the

evaporation of water, which behaves as expected theoretically. The change in mass with

respect to time was plotted in Figure 3 to analyze the rate of water removal. It can be seen

from Figure 3 that the rate of removal increases at the beginning and then steadily

decreases with time. It can also be noticed that the data is somewhat scattered and the

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plot is not very smooth. The time to reach the final mass for each trial was plotted versus

the average temperature of the trial in Figure 4. It can be noticed that there is no trend in

the points unlike the expected prediction. The graph should ideally have some linearity

that decreases with time.

Table 6 shows the heat transferred to evaporate the water of the sample at each

temperature. It can be noticed that the amount of heat transferred decreases with

decreasing temperature. The optimum time and temperature for drying the Indicating

Drierite with respect to the total energy used can be obtained from Figure 5. The

intersection of the two curves gives the best time and temperature to dry the Indicating

Drierite; that temperature and time corresponds to 191 oC and 9.2 mins.

Table 7 showcases the amount of water absorbed and desorbed in each

temperature trial; it can be noticed that the amount desorbed from the sample exceeds the

amount absorbed by the sample, which means that the sample contains some initial

moisture from the air.

There are many errors in this experiment that should be taken into account. The

temperature in the drying oven was unstable, and that is due to systematic error in the

system of the oven. The jar containing the Indicating Drierite was not sealed, which led

to moisture coming into the jar and become absorbed by the Indicating Drierite. The

opening of the oven (widely vs. narrowly) affected the temperature of the oven to drop or

stay maintained. When adding the water to the hot sample dish, some of the water

evaporates off immediately. The weighting scale used has some systematic error in it.

The weigh balance was situated on the other side of the oven which caused the hot metal

12

dish to become a possible hazard, and loss of heat due to the metal dish being exposed to

air for a period of time.

Another method that can be used to conduct the experiment is called the

thermogravimetric analysis. It is a technique that measures the weight changes in a

material as a function of time and/or temperature under controlled atmosphere. This

instrument is a better method of obtaining the desired from this experiment with high

accuracy, and a better chance of avoiding the experimental errors mentioned earlier. One

possible drawback of this technique is that the sample size is limited.

VI. Conclusion

In conclusion, the results obtained from the experiment are not ideal due to the

errors mentioned earlier. Ideally the wet Indicating Drierite decreases in weight as time

increases, and while the temperature decreases the rate of change in mass with respect to

time decreases. The optimum temperature and time was found to be 191 oC and 9.2 mins.

VII. Recommendations

In recommendation to improve the outcome of this experiment, the weight

balance should be brought closer to the oven to avoid any loss in heat and avoid the hot

metal dish from becoming a hazard. The door of the oven should not be open more than

the diameter of the metal dish to minimize the drop in temperature in the oven. The

container of the Indicating Drierite should be sealed to avoid any moisture getting into

the sample and affecting the measurements.

VIII. Reference

1) "Drierite - Indicating DRIERITE." Drierite - Indicating DRIERITE. Web.

2) Dr. Pozo de Fernandez, CHE 4115, Canvas.fit.edu, Drying Experiment

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IX. Appendix A: Sample Calculations

Change in Mass = Initial mass – Final mass = 13.91 – 13.12 = 0.79 g

Average = ∑ 𝑥𝑖

𝑁0

𝑁=

275+266+256+255+251+248+242+238+236+233+231

10= 248.3 oC

Using steam tables:

o Base case: P = 1 atm, T = 25 oC, h1 = 104.89 KJ/Kg

o Case 1: P = 1 atm, Tavg = 248.3 oC → SHV

T h

200 2875.3

248.3 h2

250 2974.3

Interpolating for the value of h2, h2 = 2970.93 KJ/Kg

Heat Transferred (q) = ℎ2 − ℎ1 = 2970.93 − 104.89 = 2866.04 𝐾𝐽

𝐾𝑔

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X. Appendix B: Experimental Data

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